3d Metal-plastic Printer For Fabrication Of Antennas On Custom And

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University of Manitoba Department of Electrical & Computer Engineering ECE 4600 Group Design Project Final Project Report 3D Metal-Plastic Printer for Fabrication of Antennas on Custom and Flexible Surfaces by Group 10 Gabriela Teles Kadeem Coleman Jongmin Kim Tyler Duke Yuhao Zhao Academic Supervisor(s) Dr. Cyrus Shafai and Dr. Lot Shafai Industry Supervisors Harris Liontas – Novra Technologies Date of Submission March 4, 2015 Copyright © 2015 Gabriela Teles, Tyler Duke, Kadeem Coleman, Yuhao Zhao, Jongmin Kim, 3D Metal-Plastic Printer Abstract 3D printing is becoming increasingly popular as a manufacturing process due to the ability to manufacture products on demand and anywhere in the world. Users are able to print objects of any geometry and of various types of materials not only in their own home, but in remote areas where these objects are not easily accessible. The main objective of our project is to design a printer with the ability to manufacture microstrip antennas quickly and on demand while still being cost efficient. In industry, traditional methods of antenna manufacturing require very expensive machinery and service technicians even for the simplest of antenna designs. Our goal is to eliminate the need for an expensive milling machine, as well as create a manufacturing technique that can be executed by users with minimal training and fewer safety precautions. Our project investigates the feasibility of integrating an inkjet system to an existing open-source plastic 3D printer design. i 3D Metal-Plastic Printer CONTRIBUTIONS Research Printable Materials Research Printer Parts Research Antenna Designs Gather Material List and Pricing Ordering of Printer Parts Ordering of Printable Materials Printer Design Antenna Design and CAD Drawing 3D Printer Build Inkjet Interfacing Inkjet System Prototype Construction Printer Calibration Antenna Build Antenna Testing Cost Analysis Legend: • Lead task • • • • Contributed ii Jongmin Kim Yuhao Zhao • • • • • • • Kadeem Coleman Tyler Duke Gabriela Teles Contributions • • • • • 3D Metal-Plastic Printer ACKNOWLEDGEMENTS Acknowledgements We would like to acknowledge the people without whom this project would not have been possible. First we would like to thank our advisors Dr. Cyrus Shafai and Dr. Lot Shafai for their valuable guidance over the course of this project. We would also like to thank Daniel Card, Aiden Topping, and Dr. Behzad Kordi for sharing their experiences and providing us with valuable project management techniques that helped make this project a success. We also would like to thank Zoran Trajkoski and Jeremy Enns for allowing us the use of their 3D printers and materials to manufacture parts for us. As well, we would like to thank the Department of Electrical and Computer Engineering for funding, allowing us to use their lab space, and especially to Sinisa Janjic and Glenn Kolansky for assisting us with ordering and acquiring all our parts and equipment. Finally we would like to thank all of our friends and family who have supported and encouraged us throughout this project and our academic careers. iii 3D Metal-Plastic Printer TABLE OF CONTENTS Table of Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Printing Essentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2.1 3D Printing Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2.2 Inkjet Printing Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Project Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.4 Report Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 3D Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1 Printer Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2 Plastic Printer Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.1 RAMPS Shield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2.2 Arduino . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.2.3 Printer Extruder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 iv 3D Metal-Plastic Printer 2.3 Printer Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.4 3D Printer Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3 Inkjet System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.1 Inkjet System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.2 Inkjet Cartridge and Carrier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3.3 Inkjet Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.3.1 Power Reduction Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.3.2 Pin Reduction Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.3.3 Cartridge Safety Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 4 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4.1 4.2 3D Plastic Printer Software Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4.1.1 Marlin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4.1.2 Repetier Host . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Inkjet System Software Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 5 Antenna Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 5.1 Chapter Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 5.2 Design Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 5.3 Preliminary Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5.4 HFSS Simulation Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 5.5 5.4.1 Design with Infinite Ground Plane . . . . . . . . . . . . . . . . . . . . . . . . 45 5.4.2 Design with Finite Ground Plane . . . . . . . . . . . . . . . . . . . . . . . . . 50 5.4.3 Design with Material Properties . . . . . . . . . . . . . . . . . . . . . . . . . 52 HFSS Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.5.1 Copper Patch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.5.2 Silver Ink Patch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 v TABLE OF CONTENTS 3D Metal-Plastic Printer 5.5.3 5.6 5.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Material Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5.6.1 Substrate Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.6.2 Conductive Ink Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Antenna Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 6 Cost Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 6.1 Industry Antenna Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 6.2 3D Printer Antenna Manufacturing Comparison . . . . . . . . . . . . . . . . . . . . . 69 7 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 7.1 Antenna Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 7.1.1 Ring Resonator Technique for Dielectric Measurement . . . . . . . . . . . . . 71 7.1.2 Silver Ink Curing Method and Curing Time Measurement . . . . . . . . . . . 71 8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Appendix A Budget . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Appendix B Marlin Software Configuration . . . . . . . . . . . . . . . . . . . . . . . . 78 Appendix C Arduino Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Appendix D HFSS Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Appendix E Curriculum Vitae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 vi 3D Metal-Plastic Printer LIST OF FIGURES List of Figures 1.1 Basic Printer Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 3D Metal-Plastic Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 3D Plastic Printer Basic Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Prusa Mendel Plastic Printer Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3 Printer Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.4 RAMPS 1.4 board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.5 A4988 Stepper Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.6 Arduino Mega 2560 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.7 Mounted Plastic Extruder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.8 Poor Print Adhesion of ABS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.9 Calibration prints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.1 (a) HPCB335W Cartridge (b) HPC6602A Cartridge . . . . . . . . . . . . . . . . . . 21 3.2 Inkjet System Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.3 Inkjet Cartridge and Sponge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.4 Schematic of Power Reduction Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.5 Schematic of Pulse Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.6 Results from Test Part 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.7 Results from Test Part 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.8 Logic Analyzer Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3.9 Inkjet Cartridge Nozzle Spray Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 vii LIST OF FIGURES 3D Metal-Plastic Printer 3.10 Schematic of Carrier Safety Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.1 3D View of a Microstrip Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 5.2 (a) 1mm Thick Substrate (b) 2mm Thick Substrate . . . . . . . . . . . . . . . . . . . 39 5.3 Top View of Microstrip Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 5.4 Ideal Radiation Pattern for PLA Substrate . . . . . . . . . . . . . . . . . . . . . . . 43 5.5 Ideal Radiation Pattern for ABS Substrate . . . . . . . . . . . . . . . . . . . . . . . 44 5.6 Antenna S11 Plot with MATLAB Dimension . . . . . . . . . . . . . . . . . . . . . . 45 5.7 Antenna Smith Chart Plot with MATLAB Dimension . . . . . . . . . . . . . . . . . 46 5.8 S11 Plot Using Patch Length Sweep . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 5.9 Input Impedance Plot Using Feeding Point Sweep . . . . . . . . . . . . . . . . . . . . 48 5.10 Radiation Pattern After Optimization with Infinite Ground Plane . . . . . . . . . . 49 5.11 Antenna Gain After Optimization with Infinite Ground Plane . . . . . . . . . . . . . 50 5.12 Radiation Pattern After Optimization with Finite Ground Plane . . . . . . . . . . . 51 5.13 Antenna Gain After Optimization with Finite Ground Plane . . . . . . . . . . . . . 52 5.14 Radiation Pattern After Optimization with Material Properties . . . . . . . . . . . . 53 5.15 Antenna Gain After Optimization with Material Properties . . . . . . . . . . . . . . 54 5.16 Antenna Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5.17 Ring Resonator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.18 Insertion Loss of Ring Resonator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 5.19 Insertion Loss of Ring Resonator with Unknown Substrate . . . . . . . . . . . . . . . 61 5.20 Halogen Lamo Curing Method Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 5.21 Deformed ABS Substrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 5.22 Constructed Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.23 S11 Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 D.1 PLA Substrate and Copper Patch Resonant Frequency . . . . . . . . . . . . . . . . . 88 D.2 PLA Substrate and Copper Patch Smith Chart . . . . . . . . . . . . . . . . . . . . . 89 viii LIST OF FIGURES 3D Metal-Plastic Printer D.3 PLA Substrate and Copper Patch Radiation Pattern . . . . . . . . . . . . . . . . . . 90 D.4 PLA Substrate and Copper Patch Gain Pattern . . . . . . . . . . . . . . . . . . . . . 91 D.5 ABS Substrate and Copper Patch Resonant Frequency . . . . . . . . . . . . . . . . . 92 D.6 ABS Substrate and Copper Patch Smith Chart . . . . . . . . . . . . . . . . . . . . . 93 D.7 ABS Substrate and Copper Patch Radiation Pattern . . . . . . . . . . . . . . . . . . 94 D.8 ABS Substrate and Copper Patch Gain Pattern . . . . . . . . . . . . . . . . . . . . . 95 D.9 PLA Substrate and Silver Patch Resonant Frequency . . . . . . . . . . . . . . . . . . 96 D.10 PLA Substrate and Silver Patch Smith Chart . . . . . . . . . . . . . . . . . . . . . . 97 D.11 PLA Substrate and Silver Patch Radiation Pattern . . . . . . . . . . . . . . . . . . . 98 D.12 PLA Substrate and Silver Patch Gain Pattern . . . . . . . . . . . . . . . . . . . . . . 99 D.13 ABS Substrate and Silver Patch Resonant Frequency . . . . . . . . . . . . . . . . . . 100 D.14 ABS Substrate and Silver Patch Smith Chart . . . . . . . . . . . . . . . . . . . . . . 101 D.15 ABS Substrate and Silver Patch Radiation Pattern . . . . . . . . . . . . . . . . . . . 102 D.16 ABS Substrate and Silver Patch Gain Pattern . . . . . . . . . . . . . . . . . . . . . . 103 ix 3D Metal-Plastic Printer LIST OF TABLES List of Tables 2.I Printer Specfications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5.I Substrate Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.II Conductor Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.III Other Antenna Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.IV Preliminary Antenna Design Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 5.V Summary of Design Step 1 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5.VI Summary of Design After Optimization with Infinite Ground Plane . . . . . . . . . . 51 5.VIIMaterial Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 5.VIIISummary of Material Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 5.IX Patch Sizes and Feeding Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5.X Dielectric Properties of ABS and PLA [1] [2] . . . . . . . . . . . . . . . . . . . . . . 57 5.XI Insertion Loss, Resonant Frequency, and 3dB Bandwidth . . . . . . . . . . . . . . . . 61 5.XIISilver Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 6.I Budget Divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 A.I Project Budget . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 x 3D Metal-Plastic Printer NOMENCLATURE Nomenclature Symbol Description HFSS High Frequency Structural Simulator. PLA Polylactic Acid. ABS Acrylonitrile Butadiene Syrene. PEC Perfect Electric Conductor. RAMPS dpi Reprap RepRap Arduino Mega Pololu Shield. Dots per Inch. Open source community driven 3D printer project. xi 3D Metal-Plastic Printer Chapter 1 Introduction 1.1 Motivation 3D printers are growing in popularity due to their vast applications. With the use of a 3D printer, almost any object can be manufactured simply and efficiently. 3D printers can be used to manufacture tools and equipment in remote areas such as the International Space Station [3]. For the purposes of our project, the design of our printer incorporates more than one type of extruder in order to print with two di↵erent materials and what is unique about this is that the printer can manufacture conductive circuits using the two materials. The intended result was to print microstrip antennas using silver nano-particle ink and plastic to create antennas for teaching and research purposes. In traditional methods of antenna manufacturing, issues arise during low volume production. The machinery and labor required to manufacture antennas are very expensive and the machines require an extensive amount of set up time. With traditional methods it is more economical to manufacture antennas in bulk, as opposed to a single unit. Furthermore, traditional methods require the use of very strong acids and handling of these materials requires very high safety standards. With our design not only do we eliminate the use of very hazardous materials, but we allow the manufacture of a single unit with significantly lower cost. 1 3D Metal-Plastic Printer 1.2 1.2 Printing Essentials Printing Essentials To present a clearer picture of this project it will be useful for the reader to understand some of the basic concepts involved in the areas of 3D printing and inkjet printing which will be outlined in the following subsections. 1.2.1 3D Printing Concepts There are several methods available for both commercial and private 3D printing varying primarily in complexity, accuracy and cost [4]. Commercial systems while providing much higher accuracy than consumer models are vastly more expensive and since this is the case this report will focus on the consumer centric method for 3D printing. For the purposes of this report, the term 3D printing will refer to a process known as thermoplastic extrusion. Thermoplastic extrusion involves a hotend, or heated nozzle, that melts a thin plastic filament in order to deposit plastic in 2D layers on a print surface. In order to form this melted plastic into various shapes and patterns the hotend and print platform are equipped with stepper motors that enable it to move in the X, Y and Z axes. A simplified diagram can be seen below in Figure 1.1. 2 3D Metal-Plastic Printer Extruder Motor 1.2 Printing Essentials Plastic Filament Z-axis Motor Z-axis Motor Printer Control Board X-axis Motor Computer Connected through USB Print Surface Power Y-axis Motor Fig. 1.1: Basic Printer Diagram 1.2.2 Inkjet Printing Concepts Inkjet printing is one of the most common ways of copying a digital image from a media device such as a computer, tablet, phone or SD card. Inkjet technologies have been mainly developed by the leaders in this field: Epson, Hewlett Packard (HP), and Canon. There are two primary types of inkjet printing, those being piezoelectric and thermal print-heads due to their fast depositing time and functionality at small scales. A piezoelectric print-head is analogous to a gun that generates an acoustic wave which separates the ink into charged droplets and then is passed through an electric field that directs the ink onto the printing surface [5]. A thermal print-head contains a series of tiny chambers that fill with ink which are then heated by a resistor causing a bubble to form and propel the ink on to the printing surface [5]. For the purpose of this project an HP thermal inkjet 3 3D Metal-Plastic Printer 1.3 Project Scope cartridge is used as the inkjet system print head. The system will be outlined in detail in Chapter 3 of this report. 1.3 Project Scope The purpose of this project was to design and construct a 3D printer that is capable of printing with two types of material, silver nano-particle ink and plastic, in order to manufacture microstrip antennas. Our design is as shown in Figure 1.2. Fig. 1.2: 3D Metal-Plastic Printer The design shown in this figure shows the basic structure of our printer taken from an opensource design. Our design modifies an existing open-source 3D printer design which consists of only 4 3D Metal-Plastic Printer 1.4 Report Outline one extruder that prints using plastic. For this project, we are included a second extruder to print our antenna conductor. This extruder is an HP inkjet cartridge that can be filled with silver ink. Our design includes a cartridge carrier of our own design, as well as modifications to the existing software in order to print with both extruders. In order to test our design a microstrip antenna design was simulated in HFSS software. With this simulation the properties of a chosen microstrip antenna design were measured. The goal was then to print the same design using our modified 3D printer and test for the same properties as measured in the simulation. This allowed us to test the precision and accuracy of our printer, as well as the potential limitations the printer would have with regards to this type of manufacturing. 1.4 Report Outline For the remainder of this report the steps taken in order to complete our printer will be outlined in the first chapter. As well, the process through which the antenna design was developed, built and tested will be detailed. Each section will discuss design decisions, hardware choices and software choices. As well, any challenges that were encountered throughout the project will be described including how they were overcome. 5 3D Metal-Plastic Printer Chapter 2 3D Plastic Printer 2.1 Printer Structure For the basic design of our printer hardware we chose to use an open source design called Prusa Mendel and modified it to include the inkjet cartridge [6]. This design was chosen to minimize the amount of time required to build and configure the main printer, due to the time constraints imposed by the project cycle. The systems structure is composed primarily of both smooth and threaded steel rods which are assembled with the use of printed plastic components supplied by the University of Manitoba’s ECE technical sta↵. The primary structure can be seen in Figure 2.1. These parts are arrayed in order to form the structure required for the Cartesian coordinate system that the printer uses. Figure 2.2 shows the various printed parts required for the construction of the printer. These components are freely available online and can be used by anyone with an existing 3D printer to fabricate parts for an additional printer[7]. 6 3D Metal-Plastic Printer 2.1 Printer Structure Fig. 2.1: 3D Plastic Printer Basic Structure As shown in Figure 2.1 the steel rods and plastic components created a triangular structure that houses the parts necessary to achieve a Cartesian coordinate space. A heated platform is located on two steel bars mounted in parallel with the Y-axis. The Y-axis also houses one stepper motor required to move the platform, connected to the platform via a GT2 timing belt and a system of pulleys and gears. Figure 2.3 shows the platform on its pulley system. 7 3D Metal-Plastic Printer 2.1 Printer Structure ! Fig. 2.2: Prusa Mendel Plastic Printer Parts Located above the platform is the X-axis. The X-axis houses the main extruder platform and despite the name actually moves in the X and Z directions and is moved via three stepper motors connected via two di↵erent apparatuses. The X direction is controlled by a single stepper motor located at one end of the axis, and is connected in much the same way as the Y-axis, that being a GT2 timing belt with a series of gears and pulleys. There are two stepper motors responsible for controlling the printer’s movement in the Z direction. The two Z direction motors are mounted at the very top of the printer, at either end of the X-axis, and are connected to that axis via two couplers, two threaded rods and a series of nuts threaded onto the rods, by turning the rods the nuts travel up the axis taking the X-axis along with them. Figure 2.7 shows the extruder mounted on its X and Z axes. The printer’s motion is kept precise along the various axes by the use of linear bearings, which travel along smooth steel rods located in all three axes. Linear bearings allow the 8 3D Metal-Plastic Printer 2.2 Plastic Printer Hardware movement of the extruder to go in the x direction with precision. Fig. 2.3: Printer Platform 2.2 Plastic Printer Hardware The printer is centrally controlled by a RAMPS 1.4 shield, which is mounted on an Arduino Mega 2560, and houses four A4988 stepper drivers and various temperature control devices including thermistors and heating elements. All of these major hardware components were purchased as a package for a basic 3D plastic printer design. In order to print with ink we also have included in our hardware an HP inkjet cartridge, and various interface electronics for the HP cartridge. 9 3D Metal-Plastic Printer 2.2.1 2.2 Plastic Printer Hardware RAMPS Shield The RAMPS 1.4 controller board interfaces with the Arduino Mega 2560 in order to control the system. This controller board is ideal for our purposes due to its low cost, and open source design. The RAMPS 1.4 board also has additional I/O ports allowing for the potential addition of added features. The additional I/O ports were first considered for use by the HP inkjet cartridge however it was later discovered that the inkjet cartridge could be operated utilizing the available stepper driver slot intended for a second plastic extruder. The RAMPS board can be seen in Figure 2.4 while a sample of the A4988 stepper drivers can be seen in Figure 2.5. Fig. 2.4: RAMPS 1.4 board 10 3D Metal-Plastic Printer 2.2 Plastic Printer Hardware Fig. 2.5: A4988 Stepper Driver 11 3D Metal-Plastic Printer 2.2.2 2.2 Plastic Printer Hardware Arduino The Arduino Mega 2560 is an open source development board that features a 16 MHz processor and 54 I/O ports. It is a relatively low cost item and widely supported for use with open source 3D printers making it ideal for our purposes. Additionally the Arduino developer environment operates a modified version of the C programming language meaning that low level manipulation of the hardware is possible along with high level computational functions supporting trajectory planning and machine orientation. Figure 2.6 shows the Arduino Mega 2560. Fig. 2.6: Arduino Mega 2560 12 3D Metal-Plastic Printer 2.2.3 2.2 Plastic Printer Hardware Printer Extruder The printer uses a nozzle system that consists of the extruder provided in our hardware package that will extrude the plastic filament, and an HP printer cartridge to extrude silver nano-particle ink. Our extruder is of a Bowden design over a typical direct drive system, that means that the mechanism that forces plastic to the hotend has been moved o↵ the X axis. A typical 3D printer uses a motor mounted directly on the X-axis, the Bowden design, by removing the stepper motor from the X-axis, reduces the weight of the X-axis allowing for increased movement speed, increased durability and reliability. The hotend that we have utilized to dispense plastic is a J-Head Mark IV-B with a 0.4 mm nozzle as shown in Figure2.7 . The J-Head was selected due to its favourable characteristics for printing PLA and ABS plastic.Heat travel up the barrel of the hotend is a significant issue for 3D printing, leading to jams that can cause failed prints and damage to the printer itself. The J-Head nozzle solves this issue by having a series of ventilated slots along the barrel preventing the majority of the heat from traveling up the barrel itself. Additionally we have selected a 0.4 mm nozzle for printing because it provides a reasonable compromise between printing resolution and printing speed. The relationship for nozzle size to print characteristics is such that greater nozzle diameter equals higher speed but lower resolution prints and visa versa. From prior experience it has been noted that 0.3 mm nozzles o↵er finer resolution however based on anecdotal evidence they take on average 10-20% longer to print than a 0.4 mm nozzle. 13 3D Metal-Plastic Printer 2.3 Printer Specifications Fig. 2.7: Mounted Plastic Extruder 2.3 Printer Specifications Over the course of the project the project specifications had to be modified due to constraints that were unknown at the outset of the project. The changes to the project stem primarily from the change in printing material which all of the other changes make possible. The printing material was changed from PLA to ABS, meaning the desired printing temperature increased from a previous 190 degree maximum to 220-240 degrees. The switch was made due to the baking process required to cure the silver ink. At the temperatures required to cure the silver ink (150 degrees C), PLA softens and visibly deforms, introducing unintended alterations into our intended antenna design. To avoid this issue the switch to ABS was made, which is a higher temperature plastic, with a melting point around 220 degrees C. ABS introduced a set of circumstances that required a slight expansion of the project, including the introduction of a heated printing platform. The heated platform is required due to the behaviour of ABS when heat is applied, that being that ABS shrinks slightly upon cooling, leading to poor print adhesion to the printing platform. The e↵ect 14 3D Metal-Plastic Printer 2.3 Printer Specifications of this can be seen in Figure 2.8. Fig. 2.8: Poor Print Adhesion of ABS The heated bed helps to alleviate the adhesion issue by maintaining a temperature of approximately 80 degrees C preventing the ABS from contracting too much. This introduction however had the e↵ect of increasing the overall power draw of the system, and increases a somewhat lengthy initial warm up period since we use the lower end of the platforms supply spectrum at 12 V. This initial warm up period could be significantly shortened by the introduction of a higher voltage power supply as the heated platform supports 12 - 24 V inputs. The heated bed also required the addition of a second temperature probe to monitor the temperature of the bed for software PID control. 15 3D Metal-Plastic Printer 2.3 Printer Specifications Table 2.1 summarizes the specifications of the 3D printer. Table 2.I: Printer Specfications Feature Print Speed XY Speed Print Temperature Cure Temperature Plastic Height Maximum Print Volume Ink Line Width Value/Range 20-50mm/s 80mm/s 185-190 C 120-150 C < 0.3mm 200x200x200mm < 75um 16 Actual Value/Range 30mm/s 50mm/s 230 °C Unknown 0.4mm 200x110x120mm Unkown 3D Metal-Plastic Printer 2.4 2.4 3D Printer Calibration 3D Printer Calibration Calibration of a 3D printer is primarily a process of educated trial and error beginning with a starting estimate and performing a multitude of test prints in order to verify the correct function of the printer. The initial setup for the printer involved calibrating the particular motor drivers for each of the axes, this involves setting a base estimate for the steps/mm calculation that Marlin uses to dictate motor motion, and adjusting the potentiometers on the various stepper drivers to calibrate the current flow to each stepper motor. To calibrate our particular printer we utilized a series of test cubes, that being 20x20x20 mm cubes. In order to determine if the printer was operating correctly the size of the printed cubes could be measured and compared to the model the print was based o↵ of. Initial print sizes did not di↵er significantly from those projected by software, though as can be seen in they are approximately 0.3 mm smaller than anticipated in X and Y and significantly shorter than anticipated in the Z axis at approximately 8 mm. The progression of the calibration prints can be seen in Figure 2.9. In order to correct for these variations the step/mm settings need to be adjusted for each incorrect axis, increased to increase the size and decreased to decease the size. Calibration of the X and Y axes were printing within 0.2 mm of correct after approximately seven test iterations, whereas the Z axis continued to cause issues well into the month of February. The Z axis as described above was significantly shorter than its intended length of 20 mm. To correct for this the steps per mm in the Z axis were increased roughly 60% and test prints were once again conducted. Upon the next series of test prints it was determined that the printer was actually moving too much in the Z axis between layers causing a lack of sufficient layer adhesion leading to prints that would essentially crumble. Decreasing the the steps per mm setting again lead to the printer printing within approximately 0.1 mm and given that layer adhesion was sufficient to form a solid object, this was deemed a success. Upon the switch to ABS, as discussed in section 2.3, calibration of the heated print area was required. An initial setting of 80 C was chosen based o↵ of recommendations from the reprap.org site. This setting was suitable for a time however, in a pursuit of prints that maintained better surface adhesion the temperature 17 3D Metal-Plastic Printer 2.4 3D Printer Calibration Fig. 2.9: Calibration prints was increased to 110 C. The setting of 110 C proved functional for a short period however heat transfer from the heated platform to its aluminum undercarriage softened the PLA fasteners for the GT2 timing belt that allows the access to move, causing the belt to slip rendering the printer inoperable. Following the melting issue, the temperature was decreased back to 85 C, which has as of time of writing resulted in significantly better print adhesion to the heated print bed. In the pursuit of print adhesion to the heated bed, several concepts were tried. As the result shown in Figure 2.8 shows the results of a combination of low printing temperature and a purely glass print surface. To increase print adhesion painters tape was applied to the print surface, increasing its roughness and thereby increasing the surface area for the extruded plastic to stick to. Painters tape improved the situation significantly however not to an ideal point as slight lifting was still observed frequently on prints. To further decrease print lifting hair spray was applied to both a bare glass surface, and the surface covered with painters tape. The bare surface with hair spray proved to be insufficient to maintain print adhesion however painters tape with hair spray provides a very stable 18 3D Metal-Plastic Printer 2.4 3D Printer Calibration adhesion, with lifts happening very infrequently. The hotend temperature was changed over the course of the project from 190 C for PLA to an initial setting of 220 C for ABS. The temperature setting for PLA was sufficient for that material, however the ABS setting proved to be somewhat low. At the 220 C temperature the ABS plastic cooled too quickly exiting the nozzle not allowing the layers of the print to fuse together correctly leading to prints that could simply be pulled apart. Increasing the temperature to 230 C solved the layer adhesion issue for ABS and is the setting the printer operates at, at the time of writing. 19 3D Metal-Plastic Printer Chapter 3 Inkjet System 3.1 Inkjet System Overview The inkjet system of the 3D printer is what is used to print the silver nano-particle ink. The ink serves as the conductive material of the patch antenna which was used to test the printer’s functionality and will be discussed in Chapter 5. The preliminary requirements for the inkjet system were a recyclable cartridge, a carriage to hold the cartridge with easy access to the control pins, and a means of controlling the ink deposition with limited amount of pins available on the Arduino. Initial research led to the testing of an o↵-the-shelf HP ink cartridge used in everyday inkjet printers. With HP cartridges we are able to empty and refill the cartridge with our silver nano-particle ink and reuse it as many times as required. Using a donated HP CB335W cartridge as a reference point we were able to determine that it is a reusable cartridge, it has 31 control pins and can print with a resolution up to 1200 DPI [8]. Figure 3.1 (a) shows the complexity of the HP CB335W cartridge. There was not sufficient information available regarding the pins used to control the nozzles of the cartridge as this information is not released to the public. To work with the donated cartridge a printer would have to be purchased corresponding to this cartridge. A logic analyzer would then have to be used to determine the voltage requirements and to establish which pins correspond to said requirements to be able to control the cartridge. This approach would also require the design and construction of a carrier for the cartridge that could be mounted to our 3D 20 3D Metal-Plastic Printer 3.1 Inkjet System Overview printer design. Due to time constraints, costs for the new printer and limited information found in research it was determined that this was not a viable option for our design. Fig. 3.1: (a) HPCB335W Cartridge (b) HPC6602A Cartridge Upon further research a Do-It-Yourself (DIY) inkjet printer project was discovered online that used a HP cartridge in its inkjet system. This DIY project referenced a cartridge (HP C6602A) which also came with a carriage assembly (HP Q2347A) that would require modifications to the open source circuitry and software in order to mount it to the existing printer structure. From the research we were also able to determine the requirements needed to control the cartridge. This cartridge and carrier combination has readily available specifications that eliminated extensive and time consuming research and testing that would have been required if we had gone with the first option as previously described [9]. Figure 3.2 shows a picture of the complete ink jet system which has the components outlined 21 3D Metal-Plastic Printer 3.1 Inkjet System Overview and labeled. The following sections of this chapter will detail the components, as well as the results of the inkjet system. The system consists of the cartridge and carrier outlined in red, and the circuitry used to drive the cartridge which is further composed of a power reduction circuit outlined in blue, pin reduction circuit outlined in purple, and safety circuit outlined in green. Fig. 3.2: Inkjet System Circuitry 22 3D Metal-Plastic Printer 3.2 3.2 Inkjet Cartridge and Carrier Inkjet Cartridge and Carrier As previously stated an HP C6602A cartridge is used as the inkjet cartridge for the inkjet system and was to be filled with silver nano-particle ink. This cartridge was chosen because there are known specifications detailing the requirements for driving it and there is also a standalone carriage assembly (HP Q2347A) available for purchase. This cartridge was available to us for a reasonable price and within a reasonable amount of shipping time, easing the time restriction related to the rest of the project. The HP C6602A cartridge requires 17-24 V to power it and it has 12 pins used to control 12 thermal nozzles which allows printing with a resolution of 96 dpi. The cartridge also requires 5 µs pulses to eject ink from a nozzle with a delay of 800 µs between the firing of a single nozzle. These delays are due to the process used in thermal inkjet printing. A thermal inkjet cartridge nozzle bank contains a series of tiny chambers that fill with ink. Under the layer of ink is a layer of metal which acts as a resistor. A large current is applied to the metal layer which vaporizes the ink layer and causes a bubble to form. The pressure from the bubble then propels the ink droplet onto to the surface being printed on. The delay allows for enough time to pass for the chambers to fill with ink [5]. In almost all printers the carriage system is part of the printer and cannot be easily removed. For the purpose of this project a carriage is needed to hold the cartridge and as a means of connecting the pins of the cartridge to the circuitry used to drive it. The carriage also has to be small enough to fit alongside the plastic extruder without interfering with its plastic printing capabilities. The HP Q2347A carriage is a standalone assembly which allows easy connection of the cartridge pins to the circuitry and it is small enough to fit alongside a plastic extruder. To recycle an HP cartridge, the process involves opening the top of the cartridge for access to the sponge which retains the ink. Once the sponge is removed from the cartridge container it should be washed to remove any remaining ink. The plastic cartridge container should also be washed thoroughly to remove any leftover ink and residue. Washing and removing any leftover ink 23 3D Metal-Plastic Printer 3.3 Inkjet Circuitry will reduce the possibility of contamination. Figure 3.3 shows the cartridge with its lid removed and the sponge after it has been washed. The ink is inserted into the plastic cartridge using a small pipet as shown in Figure 3.3. Fig. 3.3: Inkjet Cartridge and Sponge 3.3 Inkjet Circuitry The circuitry of the inkjet system is based o↵ of DIY printer project [9]. Minor modifications were made in order to incorporate this into our design. The following sections detail the circuitry used to drive the inkjet system and the tests performed to ensure that all of the components were 24 3D Metal-Plastic Printer 3.3 Inkjet Circuitry functioning as required. The inkjet system is composed of a power reduction circuit, pin reduction circuit and a cartridge safety circuit. 3.3.1 Power Reduction Circuit The HP C6602 cartridge requires 20 V to power it which is incompatible with the 12 V ATX power supply used to power the Arduino and motors. There were two options available for powering the cartridge, amplify the 12 V ATX voltage or reduce the voltage of a 32 V power supply that was available to us. The decision was made to reduce the voltage of the spare power supply so that the inkjet system could be kept separate from the 3D printer system for testing purposes. Design of the power reduction circuit is based o↵ of a circuit provided in the LM317T datasheet [?]. The LM317T is a three terminal adjustable voltage regulator that can reduce the 32 V output of the power supply to the 20 V required to power the HP C6602 cartridge. Multisim was used to run a simulation to determine the resistance needed to limit the voltage as well as ensure that the circuit would work as described in the datasheet. Figure 3.4 below shows the LM317T circuit used in simulation and the results shown on a multi-meter tool in the software. Fig. 3.4: Schematic of Power Reduction Circuit 25 3D Metal-Plastic Printer 3.3 Inkjet Circuitry The simulation showed that a resistance of approximately 4 k⌦ was needed and that the circuit would limit the voltage to approximately 20 V as shown on the multimeter. Construction of the power reduction circuit successfully reduced and limited the voltage of the 32 V power supply to approximately 20 V. A potentiometer was used as the resistor so that the resistance could be varied as needed. 3.3.2 Pin Reduction Circuit The Arduino controls all of the components of the 3D printer and as such there are a limited amount of pins available for control of the inkjet system. After construction of the plastic 3D printer a total of 16 pins remained for use. The HP C6602 cartridge prints using 12 thermal nozzles that correspond to 12 control pins. The cartridge also requires one pin to send the pulse to deposit the ink. The addition of a safety circuit which will be described in the next section required an additional pin, bringing the total pins needed for the inkjet system to 14, leaving only 2 pins remaining. In order to reduce the amount of pins needed to control the inkjet system a 74HC4067 16-channel analog demultiplexer was implemented to allow control of the nozzles of the HP C6602 cartridge using the least amount of pins as possible. The pin reduction leaves more pins available on the Arduino should future iterations of the project expand in scope. Since the cartridge operates at a higher voltage then the rated voltage of 11 V for the demultiplexer, the HP Q7461A carrier is fed through a ULN2803A high voltage darlington driver [10]. The darlington driver is composed of eight NPN darlington pairs which allow high voltage components to be connected to low voltage components without causing damage to the sensitive devices. This circuit was simulated in Mutisim but the software was limited in that it did not have a darlington array model. The circuit had to be simulated using the internal components of the darlington array provided by the ULN2803A datasheet [11]. The Figure 3.5 below shows the circuit used in the simulation. A pulse wave generator is used to simulate the Arduino signal as the input and a 20 V signal is used to simulate the output of the power reduction circuit which is required 26 3D Metal-Plastic Printer 3.3 Inkjet Circuitry to power the cartridge as previously described. The red signal in Figure 3.6 is the input signal. The pulse generator pulses low for 5 µs and high for 800 µs since the Darlington Array uses NPN transistors and has to be pulled low in order to turn on. The blue signal in Figure 3.6 is the output signal and shows that when the voltage is pulled low there is a 20 V pulse which would be used to fire a nozzle and deposit ink. There was concern with the output pulse duration as shown in Figure 3.6 as it only remains high for half of what is required, approximately 2.5 µs. It was then determined from the data sheet of the 1N4001G that the diode used is slow and has a recovery time of 2 µs [12]. Using the actual device, the ULN2803A has a rise time of 120 ns which is much less time than in the simulation [11]. Fig. 3.5: Schematic of Pulse Circuit The testing for this circuitry was done in two parts. For the first part code was written to send a single pulse (5 µs on and 800 µs o↵) from the Arduino as input, and the result was recorded 27 3D Metal-Plastic Printer 3.3 Inkjet Circuitry Fig. 3.6: Results from Test Part 1 at the output. Figure 3.7 below shows the results of this test using an oscilloscope. The test was successful with the input signal in yellow pulled low and the output signal in light blue at 20 V. The delay in the tested circuit was only 0.320 µs which is a significant decrease from the simulated value of 2 µs. This is due to the faster operation of the Darlington array as opposed to the diodes that were used in the simulation. For the second part of testing code was written to control the output of the demultiplexer using 4 pins from the Arduino. Figure 3.8 below shows that the code was able to successfully count in binary from 0-11 which chooses the corresponding output pins of the demultiplexer.The code allowed us to control which and how many nozzles are being used to deposit ink. Connection of the cartridge to the inkjet circuitry system resulted in successfully depositing ink onto a piece of paper using all 12 nozzles. Figure 3.9 shows a test that was performed to 28 3D Metal-Plastic Printer 3.3 Inkjet Circuitry Fig. 3.7: Results from Test Part 2 determine line widths based on the amount of nozzles being used. The cartridge was held roughly 1.2 cm away from the paper to create the lines shown in Figure 3.9. Figure 3.9(c) shows 12 nozzles spraying a line width of approximately 4 mm. Figure 3.9(b) shows 8 nozzles spraying a line width of approximately 2.5 mm. Figure 3.9(a) shows 4 nozzles spraying a line width of approximately 0.5 mm. 29 3D Metal-Plastic Printer 3.3 Inkjet Circuitry Fig. 3.8: Logic Analyzer Results Fig. 3.9: Inkjet Cartridge Nozzle Spray Test 30 3D Metal-Plastic Printer 3.3.3 3.3 Inkjet Circuitry Cartridge Safety Circuit Issues pertaining to the protection of the cartridge included long standby times and random misfires from the Arduino. The standby times occur when the cartridge is supplied with power but not in use. The random misfires cause misfiring of the inkjet nozzles and burn them out [13]. The options for resolving these issues were a relay, switch or transistor circuit. Through further research a means of cutting power to the cartridge safely using the Arduino was determined. A 4N35 optocoupler was selected due to its ability to handle 20 V from the power reduction circuit and only required one pin to control it from the Arduino [14]. In the design we included an LED to provide indication of when the switch is on or o↵. Figure 3.10 shows the safety circuit diagram. Fig. 3.10: Schematic of Carrier Safety Circuit 31 3D Metal-Plastic Printer 3.3 Inkjet Circuitry The optocoupler circuit was successfully tested and it is able to turn the voltage supplied to the cartridge on and o↵ as necessary. The inkjet system was tested separately from the 3D plastic printer design requiring a physical switch to be incorporated into the circuit as proof of concept. This is shown in Figure 3.2. 32 3D Metal-Plastic Printer Chapter 4 Software 4.1 3D Plastic Printer Software Overview There are two pieces of software that are essential for the correct operation of this project, those being Marlin and Repetier Host. Marlin is an open source firmware developed in the Arduino IDE and intended for Reprap 3D printers, while Repetier Host is the front end user interface required to drive the printer. Both pieces of software are extensively supported by the RepRap community and therefore the discussion following below will be a brief overview as opposed to a step by step guide. 4.1.1 Marlin As mentioned above Marlin is 3D printer firmware. Marlin features a multitude of useful features for this project’s purposes including a variety of printer fail safes, configuration options, and extra features for printer expansion. It is through the Marlin configuration files that the printer can be calibrated as explained in Section 2.4. The current configuration settings (as of time of writing) can be found in Appendix B. 33 3D Metal-Plastic Printer 4.1.2 4.2 Inkjet System Software Overview Repetier Host Repetier Host is ideally where the user of the 3D printer will spend the majority of the time working with the printer. Repetier Host controls all the serial communication with the Arduino and uses an integrated software called Slicer to transform imported 3D models into printable gcode commands. Given that the Arduino’s memory is generally not large enough to accommodate all the commands for a single print, Repetier Host bu↵ers commands for the Arduino and as such must be left open during printing. The requirement to have the printer tethered to a PC can be waived by adding an SD card slot to the printer, which is supported by Marlin, however this was beyond the scope of this project. Slicer is the section of the software where configuration of printing speeds, layer heights and the like take place at a higher level than the Marlin configuration. The configuration in Slicer is more suited to adjustments between prints as opposed to the full system changes implemented by the Marlin code. 4.2 Inkjet System Software Overview A 5 µs pulse is required to fire the nozzles of the cartridge with an 800 µs pulse between the firing of a single nozzle. Code was developed in the Arduino IDE to allow access to the ports used to trigger the nozzles. The Arduino software library includes commands for writing to the ports of the Arduino, however given the pulse width requirements this was found to be too slow and direct port manipulation was required. The software that was developed can be found in Appendix C. 34 3D Metal-Plastic Printer Chapter 5 Antenna Design 5.1 Chapter Overview Microstrip antennas, also known as patch antennas, are commonly used in wireless electronics such as smart phones, laptops and Global-Positioning Systems. They are low-profile, conformable to planar and nonplanar surfaces and easy to manufacture using printed circuit technology [15]. Due to the fact that microstrip antennas can be manufactured relatively easily, they can be integrated with other electronic circuits on the same printed circuit board to reduce the cost and space required. Microstrip antennas have some disadvantages such as low efficiency and narrow bandwidth yet they are still a popular choice in many applications. A microstrip antenna has three main parts that include a metal patch, a dielectric substrate and a ground plane as shown in Figure 5.1. To determine the printer fabrication quality, a rectangular microstrip antenna was designed in HFSS for the 3D printer to fabricate. Our microstrip antenna is designed to be a simple rectangular microstrip antenna and operates at a frequency of 3 GHz with a coaxial feed. 35 3D Metal-Plastic Printer 5.1 Chapter Overview Fig. 5.1: 3D View of a Microstrip Antenna The goal of the antenna design was to obtain the antenna dimensions and estimate its performance based on the specified design parameters. Antenna dimensions are required as input values for the 3D printer to fabricate the antenna and they include substrate length, substrate width, substrate height, patch length and patch width. Antenna performance is determined by the radiation pattern, return loss (S11) and maximum gain. This chapter is further divided into four sub-sections covering the design and testing of the antenna and will outline and detail the design decisions and results. 36 3D Metal-Plastic Printer 5.2 5.2 Design Parameters Design Parameters In order to design an antenna there a variety of design considerations including, permittivity of the substrate, loss tangent of the substrate, conductivity of the conductor, antenna operating frequency, reference impedance, patch shape, polarization and substrate thickness. The permittivity of the substrate, loss tangent of the substrate and conductivity of the conductor however, are fixed based on the material used. The types of material available for use in this project included two thermal plastics, PLA and ABS as the antenna substrate, and silver ink is used as the conductive material. These materials and their properties will be discussed in detail in section 5.6. The reference impedance of the antenna was fixed at 50 ⌦ as this is the most common resistance used in industry. It is however important to note that the parameters chosen for this design are flexible and can be changed for any specific application. The antenna operating frequency was determined based on three factors. These factors were maximum printable size of the 3D printer, accuracy of the 3D printer and the limited capabilities of the antenna measurement system. The microstrip antenna was chosen to operate at a frequency of 3 GHz. At 3 GHz, the antenna size is well below the maximum printable size of the 3D printer but also big enough such that our 3D printer accuracy is not challenged. This frequency was also chosen because it is easier for the near-field antenna measurement system available in the antenna lab of the Electrical and Computer Engineering Department at the University of Manitoba to measure the 3D printed antenna. Rectangular waveguides are manufactured for a specific frequency band according to international standards and this waveguide operates between 2.6 and 3.95 GHz therefore in order to test our design using this facility, we required a frequency within this range. The near-field antenna measurement system uses a rectangular open-ended waveguide as part of the probe. The patch shape and polarization of the antenna was hampered by our lack of knowledge and experience using HFSS to design antennas. Therefore to compensate for these deficiencies in knowledge we chose a simple and well known rectangular patch antenna design which is linearly 37 3D Metal-Plastic Printer 5.2 Design Parameters polarized. The substrate thickness was chosen based o↵ of antenna theories and the 3D printer accuracy. Research suggested the substrate thickness should be 0.3% to 5% of the free space wavelength, where the free space wavelength is the reciprocal of antenna operating frequency [15]. If the substrate is chosen to be too thin, the fringing electric field cannot be well established. If the substrate is chosen to be too thick the cross-polarized radiation would be significant reducing antenna function. Also, microstrip antennas are often fabricated using a printed circuit board with standard thicknesses. For example, RT/duroid 5880 has a list of standard thicknesses such as 0.127 mm, 0.254 mm and 0.381mm [16]. Purchasing a printed circuit board with non-standard thicknesses often means a higher cost as well as a longer fabrication time. However, the substrate thickness much more flexible for microstrip antennas built using a 3D printer. At 3 GHz, the free space wavelength is 10 cm as shown in Equation 5.1. = c 3 ⇥ 108 = = 0.1m = 10cm f 3 ⇥ 109 (5.1) Therefore the substrate can range from 0.3 mm to 5 mm thick. Because the 3D printer extruder has a resolution of 0.4 mm, we found that any substrate with thickness below 2 mm resulted in a substrate too flexible and with too many air gaps to be e↵ectively used as an antenna substrate. Figure 5.2 shows a 1 mm and a 2 mm thick substrate. 38 3D Metal-Plastic Printer 5.2 Design Parameters Fig. 5.2: (a) 1mm Thick Substrate (b) 2mm Thick Substrate As shown, the 1 mm substrate possess many air gaps. Air gaps in the substrate are undesirable as they reduce the uniformity of the substrate and adds uncertainty to the high frequency behavior of the substrate. In our case, it was decided that the substrate printed by our 3D printer should be at least 2 mm thick for any antenna substrate to be considered solid and free of obvious air gaps. The antenna design parameters are summarized in Tables 5.I, 5.II and 5.III . 39 3D Metal-Plastic Printer 5.2 Design Parameters Table 5.I: Substrate Specifications Dielectric Constant (✏r ) Loss Tangent (tan ) PLA 3.1 0.009 Substrate Material ABS 3.3-3 0.011 Table 5.II: Conductor Specifications Conductivity ( ) (S/m) Conductor Material Silver Ink 1.26 x 107 Table 5.III: Other Antenna Specifications Operating Frequency (f ) Reference Impedance (Zin) Patch Shape Polarization Substrate Thickness (h) 40 3 GHz 50 Ohms Rectangular Linear 2 mm 3D Metal-Plastic Printer 5.3 5.3 Preliminary Design Preliminary Design The preliminary design of the antenna is based on the five empirical formulas shown in equations 5.2 to 5.6 [15]. co W = xp = ( ) ⇥ f "ref f = L= r 2 "r + 1 (5.2) "r + 1 "r 1 12h + ⇥ (1 + ) 2 2 W 0.412h("ref f + 3) ⇥ "ref f 0.258 L= co p 2 ⇥ f ⇥ "ref f zf eed = 90 ⇥ "2r "r 1 ⇥ 1 2 W h + 0.264 W h + 0.8 2⇥ L L2 ⇡zo ⇥ cos2 ⇥ W2 L (5.3) (5.4) (5.5) (5.6) The empirical formulas produce design results based on ideal conditions including lossless dielectric material, lossless conductive material, and an infinitely large ground plane. The input design parameters are therefore reduced to four values; the dielectric constant ("r ), resonant frequency (f), substrate thickness (h) and input/reference impedance (Zin ). The output values are patch width (W), patch length (L) and feeding point (zf eed ). The feeding point is defined as the length measured from edge of the patch to the feeding point. Figure 5.1 and 5.3 model the dimensions of the antenna. Using the empirical formulas dimensions of the patch were obtained, as well as the feeding point and the ideal radiation pattern. To produce the radiation pattern, a MATLAB program was used to produce the radiation pattern based on the input parameters. The calculated patch length, 41 3D Metal-Plastic Printer 5.3 Preliminary Design Fig. 5.3: Top View of Microstrip Antenna patch width and feeding points are shown in Table 5.IV. This table of values served as the starting point for the antenna design using HFSS in section 5.4. Normalized radiation patterns are shown in Figure 5.4 and 5.5. Generally the radiation pattern of an antenna is a 3D view of the electric field magnitude around the antenna in the far field. However, generating a 3D radiation pattern is very challenging and costly in practice. Therefore the radiation pattern of an antenna is often expressed by two orthogonal 2D radiation patterns, namely the E-plane radiation pattern and the H-plane radiation pattern. The E-plane is the plane which contains both the direction of radiation and the direction of the electric field and the H-plane is the plane which contains both direction of radiation and direction of the magnetic field [15]. Notice there are nearly no di↵erences in patch size and the normalized radiation pattern between PLA and ABS because the dielectric constants of both materials are very similar. 42 3D Metal-Plastic Printer 5.3 Preliminary Design Table 5.IV: Preliminary Antenna Design Results Material PLA PLA Dielectric Constant 3.1 3.3 Patch Length 2.7631 2.6799 Patch Width 3.4922 3.4100 Fig. 5.4: Ideal Radiation Pattern for PLA Substrate 43 Feeding Point 0.9903 0.9658 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure Fig. 5.5: Ideal Radiation Pattern for ABS Substrate 5.4 HFSS Simulation Procedure Antenna design can be optimized further by using HFSS. HFSS is a commercial simulation software that uses a finite element method to solve Maxwell’s equations on a given structure. This software allows for the design of high frequency electronic components such as microstrip antennas [17]. The design procedure is divided into three steps and each step will be discussed in the following sub-sections. Using a step by step design process in HFSS allowed for the isolation of the e↵ect of each antenna parameter change and the overall e↵ect on antenna performance. In the following section the discussion of the design procedure will be based on the use of PLA as dielectric material as it performs largely the same as ABS, and copper will be the conductor discussed. 44 3D Metal-Plastic Printer 5.4.1 5.4 HFSS Simulation Procedure Design with Infinite Ground Plane The antenna design began with an infinite ground plane, ideal conductor and dielectric in order to focus on the e↵ect of antenna dimensions on antenna performance. As stated in section 5.3, the patch dimensions and feeding point are shown in Table 5.IV and will served as the starting point. Ideal conductors are perfect electric conductor (PEC) that have infinite conductivity, and ideal dielectrics are dielectric materials with zero dielectric loss (tan = 0). The results from Table 5.IV were entered into HFSS and the resultant plots are shown in Figures 5.6 and 5.7. The S11 plot in Figure 5.6 shows that the antenna resonant frequency had shifted to 2.88 GHz and the Smith chart in Figure 5.7 shows that the normalized antenna input impedance is not matched to the reference impedance (1 + j0). This indicates that the empirical formulas are not especially regarding the feeding point calculation. Fig. 5.6: Antenna S11 Plot with MATLAB Dimension 45 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure Fig. 5.7: Antenna Smith Chart Plot with MATLAB Dimension We can improve the design by using the optimization tool available in HFSS. The resonant frequency is known and is mainly related to the patch length (L). The input impedance of the antenna is primarily related to the position of the feeding point (zf eed ). The optimization tool allows us to run a patch length sweep and feeding point sweep with a finite step size. Figure 5.8 and 5.9 show the S11 and Smith chart for each sweep plotted on the same graph. From Figure 5.8, we can see that one of the S11 plots lands on the 3 GHz frequency which is indicated by the marker, m1. Therefore the corresponding patch length (L) will be the ideal patch length. From Figure 5.9, we can see one of the input impedance plots which shows that the antenna input impedance is closely matched to the reference impedance at 3 GHz which is indicated by the marker m1. Table 46 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure 5.V summarizes the pre and post optimization design results. Fig. 5.8: S11 Plot Using Patch Length Sweep 47 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure Fig. 5.9: Input Impedance Plot Using Feeding Point Sweep The radiation pattern and antenna gain are based on optimized patch dimensions and feeding point and are shown in Figure 5.10 and Figure 5.11 respectively. The radiation pattern includes co-polarization pattern (E ) and cross-polarization pattern (E⇥). The co-polarization pattern represents the intended radiation pattern in the far field and the cross-polarization pattern represents the unintended radiation pattern in far field. The intended radiation pattern results from the antenna patch and radiates in the direction orthogonal to the patch surface. The unintended radiation comes from various sources, but the main source for this microstrip antenna is the coaxial feeding pin which can be modeled as a very small monopole antenna. The co-polarization pattern in Figure 5.10 resembles the radiation pattern obtained using the empirical formulas and is shown in Figure 5.4. The cross-polarization pattern shown in Figure 5.10 has a low magnitude (approximately -32 dB) which is typical in the direction of radiation. The maximum antenna gain is shown in Figure 48 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure Table 5.V: Summary of Design Step 1 Results Frequency Normalized Input Impedance Patch Length (L) Patch Width (W) Feeding Point (zf eed ) Pre-Optimization 2.88 GHz 0.1095 + j0.5069 2.7631cm 3.4922cm 0.9903cm Post Optimization 3.005 GHz 1.067 - j0.011 2.64cm 3.4922cm 0.85cm 5.11 and was measured to be is 6.6482 dB which falls in the typical range for the gain of microstrip antenna. The typical range for the gain of microstrip antenna is between 5.4 dB and 8.1 dB [18]. Fig. 5.10: Radiation Pattern After Optimization with Infinite Ground Plane 49 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure Fig. 5.11: Antenna Gain After Optimization with Infinite Ground Plane 5.4.2 Design with Finite Ground Plane This section takes the optimized antenna design discussed in the previous section and modifies the ground plane to assume a finite size. In practice, the ground plane of a microstrip antenna cannot be infinitely large. As a general rule, the size of the ground plane should be kept between 70% - 100% of the antennas e↵ective wavelength for the best antenna gain unless there are other considerations. However, we decided to have a ground plane with a size of 70% of the free-space wavelength because the dielectric constant of the substrate material we used is not entirely accurate or well defined. The reasons will be discussed in section 5.6.1 in detail. Recall from Equation 5.1, the free space wavelength at 3 GHz is 10 cm. Therefore the ground plane should be a square with a size of 7 cm2 . The substrate size of a microstrip antenna is often the same as the size of the ground plane, therefore the substrate is also 7 cm2 . Conductors and dielectrics in this design step were assumed to be ideal. With a finite size ground plane, the HFSS simulation shows almost no shift in the resonance frequency but the reactive part of the input impedance possesses increases 50 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure significantly. The optimization process is carried in similar manner as described in design step one and a summary of pre and post optimized design values are shown in Table 5.VI. Table 5.VI: Summary of Design After Optimization with Infinite Ground Plane Frequency Normalized Input Impedance Patch Length (L) Patch Width (W) Feeding Point (zf eed ) Pre Optimization 3.025 GHz 0.9818 + j0.4082 2.64cm 3.4922cm 0.85cm Post Optimization 3.025 GHz 1.036 - j0.0506 2.68cm 3.4922cm 0.82cm The post optimization radiation pattern and antenna gain are shown in Figure 5.12 and Figure5.13 respectively. As the figures show, the reduced ground plane causes back radiation lobes to appear in the radiation pattern. However the radiation pattern above the 90 line is similar to the obtained under the condition of an infinitely large ground plane. Fig. 5.12: Radiation Pattern After Optimization with Finite Ground Plane 51 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure Fig. 5.13: Antenna Gain After Optimization with Finite Ground Plane 5.4.3 Design with Material Properties The final design step included the electrical properties of the materials used for building the microstrip antenna in order to more realistically simulate the antenna. Table 5.VII shown below contains the required material properties for this simulation. The HFSS simulation and optimization was again carried out in a similar manner as in the first two simulations. A summary of pre and post optimized design values are shown in Table 5.X. The radiation pattern is relatively unchanged compared to that of the simulation with the finite ground plane. The maximum gain was found to be 6.8068 dB which falls in the range of a typical microstrip antenna. In practice the typical gain of microstrip antenna is between 6 dB to 7 dB. The radiation patterns are shown in Figures 5.14 and 5.15. 52 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure Table 5.VII: Material Properties PLA PLA Copper ✏r = 3.1 tan = 0.009 5.8 x 107 S/m at 20 C Fig. 5.14: Radiation Pattern After Optimization with Material Properties 53 3D Metal-Plastic Printer 5.4 HFSS Simulation Procedure Fig. 5.15: Antenna Gain After Optimization with Material Properties Table 5.VIII: Summary of Material Properties Frequency Normalized Input Impedance Patch Length (L) Patch Width (W) Feeding Point (zf eed ) Pre Optimization 2.984 GHz 1.0355 + j0.0825 2.68cm 3.4922cm 0.82cm 54 Post Optimization 3.0251 GHz 1.0569 - j0.0627 2.65cm 3.4922cm 0.8cm 3D Metal-Plastic Printer 5.5 5.5 HFSS Simulation Results HFSS Simulation Results Having covered in detail the simulation considerations in the above sections, the results will now be briefly discussed for both the copper and silver ink patches. 5.5.1 Copper Patch There are two di↵erent simulations for the copper patch, one using PLA and the other ABS. The patch sizes and feeding points are described in Table 5.IX. For figures showing the resonant frequency, Smith chart, radiation patterns and gain patterns please consult Appendix D. Table 5.IX: Patch Sizes and Feeding Points Substrate PLA ABS 5.5.2 Width 3.4922cm 3.4100cm Length 2.65cm 2.58cm Feeding Point 0.80cm 0.77cm Silver Ink Patch Similarly, the result based on PLA and ABS substrates with a silver ink patch, including patch size and feeding point are shown in Table 5.IX. For figures showing the resonant frequency, Smith chart, radiation patterns and gain patterns please consult Appendix D. 5.5.3 Conclusion In conclusion, we obtained similar widths, lengths and feeding points for the copper patch and the silver ink patch from the result shown. However, the resonant frequency with copper patch is 0.01 GHz greater than the resonant frequency of the silver patch. The variations in radiation pattern and maximum gain are slight as the relative permittivity of both PLA and ABS are very similar. 55 3D Metal-Plastic Printer 5.6 5.6 Material Characteristics Material Characteristics To properly design a microstrip antenna, the electrical properties of the materials that will be used must be studied. Materials for this project include PLA and ABS thermal plastics that are used as the dielectric substrate, and conductive silver ink that is used as the conductive patch. For PLA and ABS thermal plastics, we are interested in knowing the relative permittivity and loss tangent. For the conductive silver ink the point of interest is the electrical conductivity. The reason the relative permittivity of the dielectric substrate must be known is because it is closely related to the patch size and feeding point location as shown in equations 5.1 to 5.6 back in section 5.3. The patch size is related to the actual resonant frequency and the feeding point determines the amount of power that is radiated to the antenna. The reason the conductivity of the patch and loss tangent of the dielectric substrate must be known is because both conductivity and loss tangent are modeled as antenna lumped input resistance from the circuit point of view. This is illustrated in Figure 5.16. These values are essential for antenna impedance matching. Fig. 5.16: Antenna Model 56 3D Metal-Plastic Printer 5.6 Material Characteristics This section is divided into two sub-sections, substrate properties, and conductive ink properties. Each will discuss the various properties of the antenna materials used in this project. 5.6.1 Substrate Properties This section describes the dielectric properties of the two thermal plastics, PLA and ABS, which are used to build the substrates of the microstrip antennas. The dielectric properties of both PLA and ABS that are of interest are the relative permittivity ("r ), also known as dielectric constant, and the loss tangent (tan ). Our research studies have shown that PLA has a relative permittivity of 3.1 and loss tangent of 0.009. ABS has a relative permittivity of 3.3 and loss tangent of 0.011[1] [2].The relative permittivity and loss tangent values are summarized in Table 5.X. As previously stated, the relative permittivity and loss tangent are functions of frequency, and the values normally increase as frequency increases. The researched dielectric properties do not represent the dielectric properties we desired since they are defined at either unknown frequencies or at frequencies much lower than 3 GHz. Table 5.X: Dielectric Properties of ABS and PLA [1] [2] Relative Permittivity ("r ) Loss Tangent (tan ) PLA 3.1 at unknown frequency 0.009 at 100kHz ABS 3.3 at 1GHz 0.011 at 1MHz A dielectric measurement technique known as the ring resonator technique can be used to determine the relative permittivity and loss tangent of dielectric materials at GHz frequency ranges. This technique requires physical components, a dielectric substrate with an unknown dielectric constant and a ring resonator that is fabricated on RT/Duroid 6006 laminate ("r = 6.15) [19]. The dielectric substrate in this project is the thermal plastic substrate printed by the 3D printer. By default the ring resonator possess a fundamental resonant frequency of 2 GHz and a specific 3 dB bandwidth. If the dielectric substrate is placed on top of the ring resonator the resonant frequency 57 3D Metal-Plastic Printer 5.6 Material Characteristics and the 3 dB bandwidth will change because the presence of the dielectric substrate acts as a superstrate for the ring resonator circuit. The whole process can be observed using a Vector Network Analyzer (VNA) and observing insertion loss (L) for both before and after testing the dielectric substrate. Knowing that the unknown relative permittivity of the dielectric substrate is related to the resonant frequency, the dielectric constant of the ring resonator substrate (RT/Duroid 6006), dimensions of the ring resonator and the dielectric substrates, we can calculate the unknown relative permittivity. The unknown loss tangent of the dielectric substrate can be calculated by knowing its own relative permittivity and insertion loss, and the relative permittivity and loss tangent of the ring resonator substrate (RT/Duroid 6006)[20]. The relationships used to calculate the unknown relative permittivity and loss tangent of the dielectric substrate are available as equations 5.1 to 5.6 and the ring resonator dimensions are also provided in literature [20]. By assuming the relative permittivity and loss tangent of the dielectric substrate do not change significantly from 2 GHz to 3 GHz, these values can be used to calculate the relative permittivity and loss tangent at 2 GHz and be applied at 3 GHz. 58 3D Metal-Plastic Printer 5.6 Material Characteristics Fig. 5.17: Ring Resonator So far the ring resonator simulation has been completed and the insertion loss plots have been obtained. During the simulation, the gap size was intentionally changed from 120 µm to 127 µm because the minimum gap size that the machine shop in the ECE Department of University of Manitoba is 127 µm. Figure 5.18 shows the insertion loss and 3 dB bandwidth of the ring resonator without the unknown dielectric substrate placed on top. As shown the change in gap size did not have a major e↵ect on the expected fundamental resonant frequency of the ring resonator, which is 2 GHz. Figure 5.19 shows insertion loss and 3 dB bandwidth of the ring resonator with the unknown dielectric substrate placed on top. As expected, the presence of the unknown substrate causes the resonant frequency and 3 dB bandwidth to change. However, the insertion loss in both cases is very high. This could be due to the impedance mismatch of the ring resonator. Table 5.XI summarizes the resonant frequency, insertion loss and 3 dB bandwidth of the ring resonator with and without the unknown substrate placed on top. 59 3D Metal-Plastic Printer 5.6 Material Characteristics Fig. 5.18: Insertion Loss of Ring Resonator 60 3D Metal-Plastic Printer 5.6 Material Characteristics Fig. 5.19: Insertion Loss of Ring Resonator with Unknown Substrate Table 5.XI: Insertion Loss, Resonant Frequency, and 3dB Bandwidth Resonant Frequency Insertion Loss (S21) 3dB Bandwidth With Unknown Substrate 2.04 GHz -26.1743 23.8 MHz With Unknown Substrate 1.95GHz -27.4778 25.2MHz Due to the time constraints placed on the project, the formulas for calculating the relative permittivity and loss tangent, the ring resonator fabrication, and the testing and measurement have yet to be implemented. This will be discussed in the future work section of the report. 61 3D Metal-Plastic Printer 5.6.2 5.6 Material Characteristics Conductive Ink Properties To build the conductive patch for the microstrip antenna, the 3D printer was to have an inkjet cartridge filled with silver ink implemented as discussed in Chapter 3. However, conductive silver ink does not have the same electrical properties as bulk silver metal. So the electrical properties particularly the electrical conductivity need to be investigated. The silver ink used is NovaCentrix Metalon JS-B25P. According to the datasheet, the silver ink trace will have 3 times to 5 times the bulk silver metal resistivity after being printed and cured [?]. The electrical resistivity is the reciprocal of the electrical conductivity of a metal. The silver ink trace should have 1/3 to 1/5 of the bulk silver metal conductivity. In order to carry out the HFSS simulation for the antenna design, it was assumed that the patch is a metal that has 1/5 the conductivity of bulk silver metal. Table 5.XII summarizes the bulk silver metal and silver ink conductivity. Table 5.XII: Silver Conductivity Conductivity Bulk Silver Metal 6.30 ⇥ 107 Silver Ink 1.26 ⇥ 107 Curing of the silver ink is critical to our 3D printer design. Because the silver ink is composed of silver nanoparticles dissolved in a solution, the printed ink trace will have significantly higher resistance if not cured. From the microscopic point of view, silver nanoparticles do not establish a proper connection unless heated and allow to fuse together. In order to carry out this curing time measurement in parallel with the construction of the 3D printer, a separate previously modified Epson WorkForce 30 inkjet printer to test the silver ink. The modification is simply replacing the existing two black ink cartridges by two refillable cartridges that are filled with silver ink. To continuously use the refillable cartridge without expiration, a YXD268-II chip resetter is used to reset the control pins on the cartridge[21]. The original Epson printer control software is used to print ink traces drawn in Microsoft Word. Because the Epson ink jet printer does not recognize any 62 3D Metal-Plastic Printer 5.6 Material Characteristics medium except paper, the desired print medium was taped to paper. To cure the printed silver ink trace a halogen lamp rated at 500 W and an oven was used. Having two sources of curing helped to confirm measured results. Various media were used including plastic transparencies, masking tape surface, and printing paper to print the silver ink on. In order to lower the resistance of the conductive ink trace, the trace must be printed multiple time in the same location with curing done after each print. For the halogen lamp curing method, we pulsed the halogen lamp in order to prevent overheating the medium. The pulse rate and pulse length depends on how close the ink trace was to the halogen lamp. Figure 5.20 shows the setup of this curing method.We found that ABS substrate can last 1 min when placed 7 cm below the halogen lamp before the substrate starts to deform. PLA substrate placed 7 cm below the halogen lamp last only 20 seconds before the substrate starts to deform. So using the halogen lamp curing method, precise control of the halogen lamp must be established using pulses at a specific frequency and duty cycle in order to prevent the substrate from overheating while curing the ink trace above it. Figure 5.21 shows an example of the ABS substrate with printed silver ink trace deformed because the halogen lamp was pulsed for too long. The substrate was placed 7 cm below the lamp and the halogen lamp was pulsed for 10 s on and 10 s o↵ for 3 min. Fig. 5.20: Halogen Lamo Curing Method Setup 63 3D Metal-Plastic Printer 5.6 Material Characteristics Fig. 5.21: Deformed ABS Substrate For the oven curing method, a research report done by Thomas Neusitzer at University of Manitoba was followed. The report suggested that each layer of the printed ink trace be baked in the oven at 120 C for 10-20 min [21]. It was found that the ABS substrate can sit comfortably in the oven without significant deformation. However due to time constraints of the project and the complexity of switching the plastic material fed to 3D printer, the PLA substrate was not tested in the oven and will be carried over into the future work of the project. To test the curing quality, the dc resistance of the ink trace was measured before and after curing. Unfortunately the only measurements obtained were in the Mega-Ohm range regardless of the curing method, curing time and printing media used. Curing the ink did not improve the resistance of the ink trace. Because of the high resistance possessed by the ink trace, functional antenna patches cannot be printed using this method. The suspected reason is that the silver ink used was improperly stored or contaminated. This problem will have to be addressed in the future work of the project. 64 3D Metal-Plastic Printer 5.7 5.7 Antenna Testing Antenna Testing The eventually fabricated antenna was constructed using the 3D printed ABS substrate, a copper tape patch and an aluminum ground plane as shown in Figure 5.22. The purpose of this antenna is to gain an insight into how the 3D printed plastic substrates perform as part of a microstrip antenna compared to those designed in HFSS. Figure 5.23 shows the S11 plot measured using the VNA in the antenna lab in the ECE department of University of Manitoba. According to figure 5.23, the resonant frequency is 3.3 GHz and has a return loss of -4.47 dB. The frequency shift and the large return loss are primarily caused by inaccurate relative permittivity, inaccurate loss tangent, discrepancies in patch size due to human error, rough substrate surface and non-uniformity of the substrate. As part of the future work, the relative permittivity should be calculated according to the shifted frequency shown in Figure 5.23. Fig. 5.22: Constructed Antenna 65 3D Metal-Plastic Printer 5.7 Antenna Testing Fig. 5.23: S11 Plot 66 3D Metal-Plastic Printer Chapter 6 Cost Analysis 6.1 Industry Antenna Manufacturing As discussed previously in the report, the purpose of the project was to design and build an 3D printer that could manufacture microstrip antennas a↵ordably and easily. With this printer, the intention was that a microstrip antenna could be made with a unique design and made on demand. In traditional antenna manufacturing processes that use milling machines and etching methods, cost is a significant issue when a small number of antennas are being made at once. The machinery used in these manufacturing methods cost anywhere from $50,000 to $100,000. Furthermore, the set up time required by a properly trained technician can encompass up to a full day. Not including material costs, the time and cost to manufacture a single antenna using these methods can cost thousands of dollars. In order to make this an economical method for industry, antennas are made in bulk to make set up and labor costs more reasonable. By manufacturing antennas in bulk the cost per unit decreases to as little as 10 cents per antenna depending on its size and design. Issues arise when small quantities of antennas are required. Ordering from large companies that build the antennas in bulk becomes prohibitively expensive. With this printer the projected cost of a single antenna could be as little as dollars per antenna. This technique can allow for the fabrication of antennas to occur with limited supervision by the user, minimal safety hazards, and minimal costs for equipment and material. 67 3D Metal-Plastic Printer 6.2 6.2 3D Printer Antenna Manufacturing Comparison 3D Printer Antenna Manufacturing Comparison The division of our budget is outlined in Table 6.I below: Table 6.I: Budget Divisions Hardware Software Printing Materials $657.59 $100.00 $422.54 The hardware cost to build the printer was significantly less than the cost of a milling machine used in industrial manufacturing methods. Not only is the hardware cheaper, but the user is able to construct and use the printer with minimal training. This design also eliminates the potential safety hazards when using the acids in traditional manufacturing methods. This design is also more economical as the software required to run the printer is entirely open source. However HFSS software, which costs approximately $100, was required to design and simulate the antenna designs that were printed. This cost was not taken from our funding, as this software was already made available through the University. The printer designed for this project is a modified version of an open source design as discussed in Chapter 2 and as such is a relatively low cost unit. In industrial methods, the materials used for antenna construction is primarily copper which is cheaper than our chosen material of silver ink however our significantly smaller hardware costs still make our design the more economical choice. The plastic filament used only costs approximately $40.00 per 1 kg. This provided more than enough plastic for extensive testing as well as a large number of printed antenna substrates. To conclude, our design eliminates the cost of very expensive machinery as well as the cost of trained technicians in both the machines use and safety precautions. Even with the slightly increased material costs, our design is better suited towards use in applications that require small numbers of manufactured antennas. 68 3D Metal-Plastic Printer Chapter 7 Future Work Future work for a 3D printer is never truly finished as the particulars of printing various structures requires modification of printing parameters to achieve optimal results. This constant state of flux comes from the fact that conditions ideal for printing flat antenna substrates quickly (greater than 100 mm/s travel speed, no filament retraction, print speeds greater than 40 mm/s) are not ideal for printing more complex structures with small infill areas and bridged sections. Given that this is the case modification for printing more complex patterns will require various changes in software and likely some degree of trial and error in order to achieve satisfactory prints. In addition to the constant optimization required for satisfactory results, integration of the inkjet cartridge into the larger system was never achieved in the scope of this project and as such must be pushed to the category of future work. Upon receiving some initial promising results, integration of the inkjet cartridge into the printer was considered. The integration involved providing the inkjet cartridge with pulses from the A4988 stepper drivers, however the required pulse width of 3 - 8 mus could not be achieved as the interrupt timing of the Marlin software restricts the minimum pulse width of the A4988 to approximately 1.3 ms. There are two possible solutions that have been considered, one being a significant rewrite of the Marlin software to accommodate for the shorter pulse duration requirements, and another being a replacement of the inkjet cartridge entirely with a Microdrop system proposed by Dr. Shafai. Microdrop systems heads are specifically 69 3D Metal-Plastic Printer 7.1 Antenna Future Work manufactured for micro dispensing of fluids and would fit the requirements of this project. The Micro drop system was ruled out over the course of this project as its cost was deemed to be too exorbitant [22]. Another issue which must be considered for the future is that of a firmware switch. The Marlin program is a serviceable program for operating a 3D printer with only one extruder however it has limited capabilities regarding multi-extruder systems. Given that the intention is to treat the inkjet cartridge as a second extruder it would be prudent to switch to a more robust multi-extruder software. Research was done into a modification of the Marlin firmware called MarlinX2. MarlinX2 contains many of the same features as the original Marlin code however it adds significant flexibility in terms of specifying and configuring multiple extruders. 7.1 Antenna Future Work Due to the time constraint of this project, some parts of the project are yet to be completed. This section is divided into 2 subsections to discuss the future work needed for improving the project. 7.1.1 Ring Resonator Technique for Dielectric Measurement To determine the relativity permittivity and loss tangent of the 3D printed substrate,the required filling factors needed in the analytical solution for calculating the relative permittivity and loss tangent need to be determined. First it will be required to confirm the accuracy of the analytical solution by using a substrate material with known relative permittivity and loss tangent in HFSS. Once the analytical solution accuracy is confirmed a ring resonator can then be fabricated for physical testing and measurement. 7.1.2 Silver Ink Curing Method and Curing Time Measurement A major problem encountered over the course of the project was that the cured ink trace exhibits very large resistance. A potential reason for the large resistance is that the silver ink used was 70 3D Metal-Plastic Printer 7.1 Antenna Future Work improperly stored or contaminated. New tests be should performed using a new bottle of silver inks for comparison. A detailed study will be needed to determine how to properly pulse the halogen lamp such that it can cure the ink trace in the least amount of time without causing damage on the substrate. 71 3D Metal-Plastic Printer Chapter 8 Conclusions This report has outlined each stage of the design process for the development of a 3D metal-plastic printer for fabrication of microstrip antennas. Expanding on an existing 3D plastic printer design, we have investigated, tested and implemented the various strategies outlined in this report in order to manufacture microstrip antennas. Design choices for the 3D printer and inkjet systems have been outlined and explained in Chapters 2 and 3 and the resultant design was developed on the basis of the decisions and specifications as outlined in this report’s introduction. Throughout testing it was determined that our method of integrating the inkjet system into the existing printer design was not possible given our time frame, and further research will need to be conducted in the future to determine the best possible solution for integration of the systems. Two possible solutions include a significant rewrite of the Marlin software used in this project, or the use of a entirely di↵erent ink deposition system manufactured by Microdrop. Furthermore, Chapter 5 outlined the design process of the microstrip antenna. This process led to the conclusion that our choice in ink and curing processes were unsuitable for antenna manufacturing. Further research will have to be made into solving the issues with the silver ink or using di↵erent conductive material for printing microstrip antenna designs. This project has successfully narrowed the scope for future work in the hopes that future students can successfully integrate an inkjet system with our current design. 72 3D Metal-Plastic Printer REFERENCES References [1] T. Nakatsuka, “Polyactic acid-coated cable,” Cable Technology Research Department Environment and Energy Labratory, Tech. Rep., 2011. [2] F. S. Shinyama K., “Study on the electrical properties of a biodegradable plastic,” in Properties and Applications of Dielectric Materials, vol. 2. IEEE, June 2003. [3] Open for Business: 3-D Printer Creates First Object in Space on International Space Station, NASA, November 2014. [4] How to Choose Your First 3D Printer, Mixshop Inc., 2015. [5] W. Contributors. (2015) Inkjet printing. Wikipedia. [Online]. Available: http://en.wikipedia. org/wiki/Inkjet printing [6] (2015, February) Prusa mendel (iteration 2). RepRap. [7] My Own RepRap Mendel Redesign, Github, 2015. [8] Inside the HP 74(CB335W) Black Inkjet Print Cartridge (Cracked Open), FreedomtoPrint, July 2010. [9] N. C. L. Patrick Hannan, Jared Knutzen and J. Markham, “Diy inkjet printer,” Ph.D. dissertation, University of Washington, December 2011. [10] 74HC4067;74HCT4067 Datasheet, December 2011. [11] ULN2803A Darlington Transistor Arrays, Texas Instruments, 2015. [12] 1N4001G-1N4007G Datasheet, Diodes Incorporated, January 2012. [13] (2012, September) Pwdr building questions. [Online]. Available: https://github.com/Pwdr/ Pwdr-Model-0.1/issues/6 [14] Optocoupler Tutorial, Electronics Tutorials, March 2015. [15] C. A. Balanis, Antenna Theory Analysis and Design, 3rd ed., J. Wiley and Sons, Eds. WileyInterscience, April 2003. 73 3D Metal-Plastic Printer REFERENCES [16] RT/duroid 5870/5880 High Frequency Laminates Datasheet, Rogers Corporation, December 2011. [17] ANYSYS Product Simulation, ANSYS. [18] P. Mojabi, “Paraboloid reflector antennas introduction,” University of Manitoba, Tech. Rep., 2015. [19] RT/duroRT 6006/6010LM High Frequency Laminates Datasheet, Rogers Corporation. [20] Dielectric Characterization of Materials using a Modified Microstrip Ring Resonator Technique, ser. 4, vol. 19, IEEE Transactions On Dielectrics And Electrical Insulation, 2012. [21] T. Neusitzer, “Inkjet printing and printed circuit boards and novacentrix metalon conductive inks,” Ph.D. dissertation, University of Manitoba, August 2013. [22] Microdrop. [Online]. Available: www.microdrop.com 74 3D Metal-Plastic Printer Appendix A Budget The budget for this project is $1217.47 and is outlined in the table on the next page. The Department of Electrical and Computer Engineering has provided us with $657.57 worth of funding. $200.00 dollars of the total budget did not have to be paid from our funding, as they were items already available to us through our supervisor The remaining $341.23 of our budget was funded by our supervisor, Dr. Cyrus Shafai. Please note: *Items that were already provided or were acquired without funds from the budget. **Items funded by supervisor ***Miscellaneous parts such as resistors and capacitors required for circuit hardware. 75 3D Metal-Plastic Printer Table A.I: Project Budget Item Electronics Package M8 Threaded Rod 8mm Smooth Bar Prusa Mendel Hardware Set Linear Bearing PLA Printer Filament (Black) Internal PC Power Supply Bowden Extruder Hardware Refillable Ink Jet Cartridge Cartridge Carrier Wiper Control Antenna Conductor Inkshield PCB Stepper Motor Driver MK8 Drive Gear *Machine Shop Time *PCB *HFSS Software *Misc. Wood Products *HP Desktop Printer **Silver Printer Ink **Halogen Lamp **ABS Filament ** 5mmx8mm Coupling ***Misc. Parts Supplier Sainsmart Mixshop Mixshop Mixshop Mixshop Amazon Amazon Ebay Transact Transact Transact Department NicolasLewis Mixshop Ebay Department Department Department Gabriela Kadeem Department Home Depot Amazon Mixshop Digikey Unit Cost $259.99 $21.00 $19.00 $18.50 $1.80 $32.99 $38.37 $23.13 $15.45 $8.25 $0.34 $0.00 $9.00 $8.19 $10.60 $0.00 $1.00 $50.00 $0.00 $0.00 $250 $10.98 $35.00 $2.58 $27.63 76 Quantity 1 1 1 1 6 1 1 1 1 1 1 1 1 1 1 8 hrs 100 2 TBD 1 1 1 1 2 1 Shipping Cost $0.00 $5.00 $5.00 $5.00 $5.00 $0.00 $0.00 $7.00 $10.35 $10.35 $10.35 $0.00 $3.00 $0.00 $7.72 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $4.55 $16.87 $17.23 Total: Total $259.99 $26.00 $24.00 $23.50 $15.80 $32.99 $38.37 $30.13 $25.80 $18.60 $10.69 $0.00 $12.00 $8.19 $18.32 $0.00 $100.00 $100.00 $0.00 $0.00 $250.00 $10.98 $39.55 $22.03 $44.86 $1217.47 3D Metal-Plastic Printer Appendix B Marlin Software Configuration #ifndef CONFIGURATION_H #define CONFIGURATION_H // This configuration file contains the basic settings. // Advanced settings can be found in Configuration_adv.h // BASIC SETTINGS: select your board type, temperature sensor type, axis scaling, and endstop configuration //=========================================================================== //============================= DELTA Printer =============================== //=========================================================================== // For a Delta printer rplace the configuration files wilth the files in the // example_configurations/delta directory. // // User-specified version info of this build to display in [Pronterface, etc] terminal window during // startup. Implementation of an idea by Prof Braino to inform user that any changes made to this // build by the user have been successfully uploaded into firmware. #define STRING_VERSION_CONFIG_H __DATE__ " " __TIME__ // build date and time #define STRING_CONFIG_H_AUTHOR "(none, default config)" // Who made the changes. // SERIAL_PORT selects which serial port should be used for communication with the host. // This allows the connection of wireless adapters (for instance) to non-default port pins. // Serial port 0 is still used by the Arduino bootloader regardless of this setting. #define SERIAL_PORT 0 // This determines the communication speed of the printer // This determines the communication speed of the printer #define BAUDRATE 250000 // This enables the serial port associated to the Bluetooth interface //#define BTENABLED // Enable BT interface on AT90USB devices //// The following define selects which electronics board you have. Please choose the one that matches your setup // 10 = Gen7 custom (Alfons3 Version) "https://github.com/Alfons3/Generation_7_Electronics" // 11 = Gen7 v1.1, v1.2 = 11 // 12 = Gen7 v1.3 // 13 = Gen7 v1.4 // 2 = Cheaptronic v1.0 // 20 = Sethi 3D_1 // 3 = MEGA/RAMPS up to 1.2 = 3 // 33 = RAMPS 1.3 / 1.4 (Power outputs: Extruder, Fan, Bed) // 34 = RAMPS 1.3 / 1.4 (Power outputs: Extruder0, Extruder1, Bed) // 35 = RAMPS 1.3 / 1.4 (Power outputs: Extruder, Fan, Fan) // 4 = Duemilanove w/ ATMega328P pin assignment // 5 = Gen6 // 51 = Gen6 deluxe // 6 = Sanguinololu < 1.2 // 62 = Sanguinololu 1.2 and above // 63 = Melzi // 64 = STB V1.1 // 65 = Azteeg X1 // 66 = Melzi with ATmega1284 (MaKr3d version) // 67 = Azteeg X3 // 7 = Ultimaker // 71 = Ultimaker (Older electronics. Pre 1.5.4. This is rare) // 77 = 3Drag Controller 77 3D Metal-Plastic Printer // // // // // // // // // // // // // 8 = Teensylu 80 = Rumba 81 = Printrboard (AT90USB1286) 82 = Brainwave (AT90USB646) 83 = SAV Mk-I (AT90USB1286) 9 = Gen3+ 70 = Megatronics 701= Megatronics v2.0 702= Minitronics v1.0 90 = Alpha OMCA board 91 = Final OMCA board 301 = Rambo 21 = Elefu Ra Board (v3) #ifndef MOTHERBOARD #define MOTHERBOARD 33 #endif // Define this to set a custom name for your generic Mendel, // #define CUSTOM_MENDEL_NAME "This Mendel" // Define this to set a unique identifier for this printer, (Used by some programs to differentiate between machines) // You can use an online service to generate a random UUID. (eg http://www.uuidgenerator.net/version4) // #define MACHINE_UUID "00000000-0000-0000-0000-000000000000" // This defines the number of extruders #define EXTRUDERS 1 //// The following define selects which power supply you have. Please choose the one that matches your setup // 1 = ATX // 2 = X-Box 360 203Watts (the blue wire connected to PS_ON and the red wire to VCC) #define POWER_SUPPLY 1 // Define this to have the electronics keep the powersupply off on startup. If you don’t know what this is leave it. // #define PS_DEFAULT_OFF //=========================================================================== //=============================Thermal Settings ============================ //=========================================================================== // //--NORMAL IS 4.7kohm PULLUP!-- 1kohm pullup can be used on hotend sensor, using correct resistor and table // //// Temperature sensor settings: // -2 is thermocouple with MAX6675 (only for sensor 0) // -1 is thermocouple with AD595 // 0 is not used // 1 is 100k thermistor - best choice for EPCOS 100k (4.7k pullup) // 2 is 200k thermistor - ATC Semitec 204GT-2 (4.7k pullup) // 3 is mendel-parts thermistor (4.7k pullup) // 4 is 10k thermistor !! do not use it for a hotend. It gives bad resolution at high temp. !! // 5 is 100K thermistor - ATC Semitec 104GT-2 (Used in ParCan & J-Head) (4.7k pullup) // 6 is 100k EPCOS - Not as accurate as table 1 (created using a fluke thermocouple) (4.7k pullup) // 7 is 100k Honeywell thermistor 135-104LAG-J01 (4.7k pullup) // 71 is 100k Honeywell thermistor 135-104LAF-J01 (4.7k pullup) // 8 is 100k 0603 SMD Vishay NTCS0603E3104FXT (4.7k pullup) // 9 is 100k GE Sensing AL03006-58.2K-97-G1 (4.7k pullup) // 10 is 100k RS thermistor 198-961 (4.7k pullup) // 60 is 100k Maker’s Tool Works Kapton Bed Thermister // // 1k ohm pullup tables - This is not normal, you would have to have changed out your 4.7k for 1k // (but gives greater accuracy and more stable PID) // 51 is 100k thermistor - EPCOS (1k pullup) // 52 is 200k thermistor - ATC Semitec 204GT-2 (1k pullup) // 55 is 100k thermistor - ATC Semitec 104GT-2 (Used in ParCan & J-Head) (1k pullup) #define #define #define #define TEMP_SENSOR_0 1 TEMP_SENSOR_1 0 TEMP_SENSOR_2 0 TEMP_SENSOR_BED 1 // This makes temp sensor 1 a redundant sensor for sensor 0. If the temperatures difference between these sensors is to high the print will be aborted. //#define TEMP_SENSOR_1_AS_REDUNDANT #define MAX_REDUNDANT_TEMP_SENSOR_DIFF 10 // Actual temperature must be close to target for this long before M109 returns success #define TEMP_RESIDENCY_TIME 10 // (seconds) #define TEMP_HYSTERESIS 3 // (degC) range of +/- temperatures considered "close" to the target one #define TEMP_WINDOW 1 // (degC) Window around target to start the residency timer x degC early. // The minimal temperature defines the temperature below which the heater will not be enabled It is used // to check that the wiring to the thermistor is not broken. 78 3D Metal-Plastic Printer // Otherwise this would lead to the heater being powered on all the time. #define HEATER_0_MINTEMP 5 #define HEATER_1_MINTEMP 5 #define HEATER_2_MINTEMP 5 #define BED_MINTEMP 5 // When temperature exceeds max temp, your heater will be switched off. // This feature exists to protect your hotend from overheating accidentally, but *NOT* from thermistor short/failure! // You should use MINTEMP for thermistor short/failure protection. #define HEATER_0_MAXTEMP 240 #define HEATER_1_MAXTEMP 220 #define HEATER_2_MAXTEMP 220 #define BED_MAXTEMP 150 // If your bed has low resistance e.g. .6 ohm and throws the fuse you can duty cycle it to reduce the // average current. The value should be an integer and the heat bed will be turned on for 1 interval of // HEATER_BED_DUTY_CYCLE_DIVIDER intervals. //#define HEATER_BED_DUTY_CYCLE_DIVIDER 4 // PID settings: // Comment the following line to disable PID and enable bang-bang. #define PIDTEMP #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current #define PID_MAX 255 // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current #ifdef PIDTEMP //#define PID_DEBUG // Sends debug data to the serial port. //#define PID_OPENLOOP 1 // Puts PID in open loop. M104/M140 sets the output power from 0 to PID_MAX #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature // is more then PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max. #define PID_INTEGRAL_DRIVE_MAX 255 //limit for the integral term #define K1 0.95 //smoothing factor within the PID #define PID_dT ((16.0 * 8.0)/(F_CPU / 64.0 / 256.0)) //sampling period of the temperature routine // If you are using a preconfigured hotend then you can use one of the value sets by uncommenting it // Ultimaker #define DEFAULT_Kp 22.2 #define DEFAULT_Ki 1.08 #define DEFAULT_Kd 114 // Makergear // #define // #define // #define DEFAULT_Kp 7.0 DEFAULT_Ki 0.1 DEFAULT_Kd 12 // Mendel Parts V9 on 12V // #define DEFAULT_Kp 63.0 // #define DEFAULT_Ki 2.25 // #define DEFAULT_Kd 440 #endif // PIDTEMP // Bed Temperature Control // Select PID or bang-bang with PIDTEMPBED. If bang-bang, BED_LIMIT_SWITCHING will enable hysteresis // // Uncomment this to enable PID on the bed. It uses the same frequency PWM as the extruder. // If your PID_dT above is the default, and correct for your hardware/configuration, that means 7.689Hz, // which is fine for driving a square wave into a resistive load and does not significantly impact you FET heating. // This also works fine on a Fotek SSR-10DA Solid State Relay into a 250W heater. // If your configuration is significantly different than this and you don’t understand the issues involved, you probably // shouldn’t use bed PID until someone else verifies your hardware works. // If this is enabled, find your own PID constants below. //#define PIDTEMPBED // //#define BED_LIMIT_SWITCHING // This sets the max power delivered to the bed, and replaces the HEATER_BED_DUTY_CYCLE_DIVIDER option. // all forms of bed control obey this (PID, bang-bang, bang-bang with hysteresis) // setting this to anything other than 255 enables a form of PWM to the bed just like HEATER_BED_DUTY_CYCLE_DIVIDER did, // so you shouldn’t use it unless you are OK with PWM on your bed. (see the comment on enabling PIDTEMPBED) #define MAX_BED_POWER 255 // limits duty cycle to bed; 255=full current #ifdef PIDTEMPBED //120v 250W silicone heater into 4mm borosilicate (MendelMax 1.5+) //from FOPDT model - kp=.39 Tp=405 Tdead=66, Tc set to 79.2, aggressive factor of .15 (vs .1, 1, 10) #define DEFAULT_bedKp 10.00 #define DEFAULT_bedKi .023 #define DEFAULT_bedKd 305.4 //120v 250W silicone heater into 4mm borosilicate (MendelMax 1.5+) //from pidautotune // #define DEFAULT_bedKp 97.1 // #define DEFAULT_bedKi 1.41 // #define DEFAULT_bedKd 1675.16 79 3D Metal-Plastic Printer // FIND YOUR OWN: "M303 E-1 C8 S90" to run autotune on the bed at 90 degreesC for 8 cycles. #endif // PIDTEMPBED //this prevents dangerous Extruder moves, i.e. if the temperature is under the limit //can be software-disabled for whatever purposes by #define PREVENT_DANGEROUS_EXTRUDE //if PREVENT_DANGEROUS_EXTRUDE is on, you can still disable (uncomment) very long bits of extrusion separately. #define PREVENT_LENGTHY_EXTRUDE #define EXTRUDE_MINTEMP 170 #define EXTRUDE_MAXLENGTH (X_MAX_LENGTH+Y_MAX_LENGTH) //prevent extrusion of very large distances. //=========================================================================== //=============================Mechanical Settings=========================== //=========================================================================== // Uncomment the following line to enable CoreXY kinematics // #define COREXY // coarse Endstop Settings #define ENDSTOPPULLUPS // Comment this out (using // at the start of the line) to disable the endstop pullup resistors #ifndef ENDSTOPPULLUPS // fine Enstop settings: Individual Pullups. will be ignored if ENDSTOPPULLUPS is defined // #define ENDSTOPPULLUP_XMAX // #define ENDSTOPPULLUP_YMAX // #define ENDSTOPPULLUP_ZMAX // #define ENDSTOPPULLUP_XMIN // #define ENDSTOPPULLUP_YMIN // #define ENDSTOPPULLUP_ZMIN #endif #ifdef ENDSTOPPULLUPS #define ENDSTOPPULLUP_XMAX #define ENDSTOPPULLUP_YMAX #define ENDSTOPPULLUP_ZMAX #define ENDSTOPPULLUP_XMIN #define ENDSTOPPULLUP_YMIN #define ENDSTOPPULLUP_ZMIN #endif // The pullups are needed if you directly connect const bool X_MIN_ENDSTOP_INVERTING = true; // set const bool Y_MIN_ENDSTOP_INVERTING = true; // set const bool Z_MIN_ENDSTOP_INVERTING = true; // set const bool X_MAX_ENDSTOP_INVERTING = true; // set const bool Y_MAX_ENDSTOP_INVERTING = true; // set const bool Z_MAX_ENDSTOP_INVERTING = true; // set //#define DISABLE_MAX_ENDSTOPS //#define DISABLE_MIN_ENDSTOPS a mechanical endswitch between to true to invert the logic of to true to invert the logic of to true to invert the logic of to true to invert the logic of to true to invert the logic of to true to invert the logic of the the the the the the the signal and ground pins. endstop. endstop. endstop. endstop. endstop. endstop. // Disable max endstops for compatibility with endstop checking routine #if defined(COREXY) && !defined(DISABLE_MAX_ENDSTOPS) #define DISABLE_MAX_ENDSTOPS #endif // For Inverting Stepper Enable Pins (Active Low) use 0, Non Inverting (Active High) use 1 #define X_ENABLE_ON 0 #define Y_ENABLE_ON 0 #define Z_ENABLE_ON 0 #define E_ENABLE_ON 0 // For all extruders // Disables axis when it’s not being used. #define DISABLE_X false #define DISABLE_Y false #define DISABLE_Z false #define DISABLE_E false // For all extruders #define #define #define #define #define #define INVERT_X_DIR true INVERT_Y_DIR false INVERT_Z_DIR true INVERT_E0_DIR true INVERT_E1_DIR false INVERT_E2_DIR false // for Mendel set to false, for Orca set to true // for Mendel set to true, for Orca set to false // for Mendel set to false, for Orca set to true // for direct drive extruder v9 set to true, for geared extruder set to false // for direct drive extruder v9 set to true, for geared extruder set to false // for direct drive extruder v9 set to true, for geared extruder set to false // ENDSTOP SETTINGS: // Sets direction of endstops when homing; 1=MAX, -1=MIN #define X_HOME_DIR -1 #define Y_HOME_DIR -1 80 3D Metal-Plastic Printer #define Z_HOME_DIR -1 #define min_software_endstops true // If true, axis won’t move to coordinates less than HOME_POS. #define max_software_endstops true // If true, axis won’t move to coordinates greater than the defined lengths below. // Travel limits after homing #define X_MAX_POS 240 #define X_MIN_POS 0 #define Y_MAX_POS 205 #define Y_MIN_POS 0 #define Z_MAX_POS 200 #define Z_MIN_POS 0 #define X_MAX_LENGTH (X_MAX_POS #define Y_MAX_LENGTH (Y_MAX_POS #define Z_MAX_LENGTH (Z_MAX_POS //============================= - X_MIN_POS) - Y_MIN_POS) - Z_MIN_POS) Bed Auto Leveling =========================== //#define ENABLE_AUTO_BED_LEVELING // Delete the comment to enable (remove // at the start of the line) #ifdef ENABLE_AUTO_BED_LEVELING // these are the positions on the bed to do the probing #define LEFT_PROBE_BED_POSITION 15 #define RIGHT_PROBE_BED_POSITION 170 #define BACK_PROBE_BED_POSITION 180 #define FRONT_PROBE_BED_POSITION 20 // these are the offsets to the prob #define X_PROBE_OFFSET_FROM_EXTRUDER #define Y_PROBE_OFFSET_FROM_EXTRUDER #define Z_PROBE_OFFSET_FROM_EXTRUDER #define Z_RAISE_BEFORE_HOMING 4 #define XY_TRAVEL_SPEED 8000 #define Z_RAISE_BEFORE_PROBING 15 #define Z_RAISE_BETWEEN_PROBINGS 5 relative to the extruder tip (Hotend - Probe) -25 -29 -12.35 // (in mm) Raise Z before homing (G28) for Probe Clearance. // Be sure you have this distance over your Z_MAX_POS in case // X and Y axis travel speed between probes, in mm/min //How much the extruder will be raised before traveling to the first probing point. //How much the extruder will be raised when traveling from between next probing points //If defined, the Probe servo will be turned on only during movement and then turned off to avoid jerk //The value is the delay to turn the servo off after powered on - depends on the servo speed; 300ms is good value, but you can try lower it. // You MUST HAVE the SERVO_ENDSTOPS defined to use here a value higher than zero otherwise your code will not compile. // #define PROBE_SERVO_DEACTIVATION_DELAY 300 //If you have enabled the Bed Auto Levelling and are using the same Z Probe for Z Homing, //it is highly recommended you let this Z_SAFE_HOMING enabled!!! #define Z_SAFE_HOMING // // // // // // This feature is meant to avoid Z homing with probe outside the bed area. When defined, it will: - Allow Z homing only after X and Y homing AND stepper drivers still enabled - If stepper drivers timeout, it will need X and Y homing again before Z homing - Position the probe in a defined XY point before Z Homing when homing all axis (G28) - Block Z homing only when the probe is outside bed area. #ifdef Z_SAFE_HOMING #define Z_SAFE_HOMING_X_POINT (X_MAX_LENGTH/2) #define Z_SAFE_HOMING_Y_POINT (Y_MAX_LENGTH/2) // X point for Z homing when homing all axis (G28) // Y point for Z homing when homing all axis (G28) #endif // with accurate bed leveling, the bed is sampled in a ACCURATE_BED_LEVELING_POINTSxACCURATE_BED_LEVELING_POINTS grid and least squares solution is calculated // Note: this feature occupies 10’206 byte #define ACCURATE_BED_LEVELING #ifdef ACCURATE_BED_LEVELING // I wouldn’t see a reason to go above 3 (=9 probing points on the bed) #define ACCURATE_BED_LEVELING_POINTS 2 #endif #endif // The position of the homing switches //#define MANUAL_HOME_POSITIONS // If defined, MANUAL_*_HOME_POS below will be used //#define BED_CENTER_AT_0_0 // If defined, the center of the bed is at (X=0, Y=0) 81 3D Metal-Plastic Printer //Manual homing switch locations: // For deltabots this means top and center of the cartesian print volume. #define MANUAL_X_HOME_POS 0 #define MANUAL_Y_HOME_POS 0 #define MANUAL_Z_HOME_POS 0 //#define MANUAL_Z_HOME_POS 402 // For delta: Distance between nozzle and print surface after homing. //// MOVEMENT SETTINGS #define NUM_AXIS 4 // The axis order in all axis related arrays is X, Y, Z, E #define HOMING_FEEDRATE {50*60, 50*60, 4*60, 0} // set the homing speeds (mm/min) // default settings #define DEFAULT_AXIS_STEPS_PER_UNIT #define DEFAULT_MAX_FEEDRATE #define DEFAULT_MAX_ACCELERATION {95,95,1030.0*8/3,132*1.1} // default steps per unit for Ultimaker {200, 200, 3, 25} // (mm/sec) {9000,9000,100,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for o #define DEFAULT_ACCELERATION #define DEFAULT_RETRACT_ACCELERATION 2000 3000 // // // // // // X, Y, Z and E max acceleration in mm/s^2 for printing moves // X, Y, Z and E max acceleration in mm/s^2 for retracts Offset of the extruders (uncomment if using more than one and relying on firmware to position when changing). The offset has to be X=0, Y=0 for the extruder 0 hotend (default extruder). For the other hotends it is their distance from the extruder 0 hotend. #define EXTRUDER_OFFSET_X {0.0, 20.00} // (in mm) for each extruder, offset of the hotend on the X axis #define EXTRUDER_OFFSET_Y {0.0, 5.00} // (in mm) for each extruder, offset of the hotend on the Y axis // The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously) #define DEFAULT_XYJERK 15.0 // (mm/sec) #define DEFAULT_ZJERK 0.4 // (mm/sec) #define DEFAULT_EJERK 5.0 // (mm/sec) //=========================================================================== //=============================Additional Features=========================== //=========================================================================== // EEPROM // the microcontroller can store settings in the EEPROM, e.g. max velocity... // M500 - stores paramters in EEPROM // M501 - reads parameters from EEPROM (if you need reset them after you changed them temporarily). // M502 - reverts to the default "factory settings". You still need to store them in EEPROM afterwards if you want to. //define this to enable eeprom support //#define EEPROM_SETTINGS //to disable EEPROM Serial responses and decrease program space by ~1700 byte: comment this out: // please keep turned on if you can. //#define EEPROM_CHITCHAT // Preheat Constants #define PLA_PREHEAT_HOTEND_TEMP 180 #define PLA_PREHEAT_HPB_TEMP 70 #define PLA_PREHEAT_FAN_SPEED 255 // Insert Value between 0 and 255 #define ABS_PREHEAT_HOTEND_TEMP 240 #define ABS_PREHEAT_HPB_TEMP 100 #define ABS_PREHEAT_FAN_SPEED 255 // Insert Value between 0 and 255 //LCD and //#define //#define //#define //#define //#define //#define //#define //#define SD support ULTRA_LCD //general lcd support, also 16x2 DOGLCD // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family) SDSUPPORT // Enable SD Card Support in Hardware Console SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you’re getting volume init error) ENCODER_PULSES_PER_STEP 1 // Increase if you have a high resolution encoder ENCODER_STEPS_PER_MENU_ITEM 5 // Set according to ENCODER_PULSES_PER_STEP or your liking ULTIMAKERCONTROLLER //as available from the ultimaker online store. ULTIPANEL //the ultipanel as on thingiverse // The MaKr3d Makr-Panel with graphic controller and SD support // http://reprap.org/wiki/MaKr3d_MaKrPanel //#define MAKRPANEL // The RepRapDiscount Smart Controller (white PCB) // http://reprap.org/wiki/RepRapDiscount_Smart_Controller //#define REPRAP_DISCOUNT_SMART_CONTROLLER // The GADGETS3D G3D LCD/SD Controller (blue PCB) // http://reprap.org/wiki/RAMPS_1.3/1.4_GADGETS3D_Shield_with_Panel //#define G3D_PANEL // The RepRapDiscount FULL GRAPHIC Smart Controller (quadratic white PCB) // http://reprap.org/wiki/RepRapDiscount_Full_Graphic_Smart_Controller // // ==> REMEMBER TO INSTALL U8glib to your ARDUINO library folder: http://code.google.com/p/u8glib/wiki/u8glib //#define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER 82 3D Metal-Plastic Printer // The RepRapWorld REPRAPWORLD_KEYPAD v1.1 // http://reprapworld.com/?products_details&products_id=202&cPath=1591_1626 //#define REPRAPWORLD_KEYPAD //#define REPRAPWORLD_KEYPAD_MOVE_STEP 10.0 // how much should be moved when a key is pressed, eg 10.0 means 10mm per click // The Elefu RA Board Control Panel // http://www.elefu.com/index.php?route=product/product&product_id=53 // REMEMBER TO INSTALL LiquidCrystal_I2C.h in your ARUDINO library folder: https://github.com/kiyoshigawa/LiquidCrystal_I2C //#define RA_CONTROL_PANEL //automatic expansion #if defined (MAKRPANEL) #define DOGLCD #define SDSUPPORT #define ULTIPANEL #define NEWPANEL #define DEFAULT_LCD_CONTRAST 17 #endif #if defined (REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER) #define DOGLCD #define U8GLIB_ST7920 #define REPRAP_DISCOUNT_SMART_CONTROLLER #endif #if defined(ULTIMAKERCONTROLLER) || defined(REPRAP_DISCOUNT_SMART_CONTROLLER) || defined(G3D_PANEL) #define ULTIPANEL #define NEWPANEL #endif #if defined(REPRAPWORLD_KEYPAD) #define NEWPANEL #define ULTIPANEL #endif #if defined(RA_CONTROL_PANEL) #define ULTIPANEL #define NEWPANEL #define LCD_I2C_TYPE_PCA8574 #define LCD_I2C_ADDRESS 0x27 // I2C Address of the port expander #endif //I2C PANELS //#define LCD_I2C_SAINSMART_YWROBOT #ifdef LCD_I2C_SAINSMART_YWROBOT // This uses the LiquidCrystal_I2C library ( https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/Home ) // Make sure it is placed in the Arduino libraries directory. #define LCD_I2C_TYPE_PCF8575 #define LCD_I2C_ADDRESS 0x27 // I2C Address of the port expander #define NEWPANEL #define ULTIPANEL #endif // PANELOLU2 LCD with status LEDs, separate encoder and click inputs //#define LCD_I2C_PANELOLU2 #ifdef LCD_I2C_PANELOLU2 // This uses the LiquidTWI2 library v1.2.3 or later ( https://github.com/lincomatic/LiquidTWI2 ) // Make sure the LiquidTWI2 directory is placed in the Arduino or Sketchbook libraries subdirectory. // (v1.2.3 no longer requires you to define PANELOLU in the LiquidTWI2.h library header file) // Note: The PANELOLU2 encoder click input can either be directly connected to a pin // (if BTN_ENC defined to != -1) or read through I2C (when BTN_ENC == -1). #define LCD_I2C_TYPE_MCP23017 #define LCD_I2C_ADDRESS 0x20 // I2C Address of the port expander #define LCD_USE_I2C_BUZZER //comment out to disable buzzer on LCD #define NEWPANEL #define ULTIPANEL #endif // Panucatt VIKI LCD with status LEDs, integrated click & L/R/U/P buttons, separate encoder inputs //#define LCD_I2C_VIKI #ifdef LCD_I2C_VIKI // This uses the LiquidTWI2 library v1.2.3 or later ( https://github.com/lincomatic/LiquidTWI2 ) // Make sure the LiquidTWI2 directory is placed in the Arduino or Sketchbook libraries subdirectory. // Note: The pause/stop/resume LCD button pin should be connected to the Arduino // BTN_ENC pin (or set BTN_ENC to -1 if not used) #define LCD_I2C_TYPE_MCP23017 #define LCD_I2C_ADDRESS 0x20 // I2C Address of the port expander #define LCD_USE_I2C_BUZZER //comment out to disable buzzer on LCD (requires LiquidTWI2 v1.2.3 or later) #define NEWPANEL #define ULTIPANEL #endif 83 3D Metal-Plastic Printer // Shift register panels // --------------------// 2 wire Non-latching LCD SR from: // https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/schematics#!shiftregister-connection //#define SR_LCD #ifdef SR_LCD #define SR_LCD_2W_NL // Non latching 2 wire shiftregister //#define NEWPANEL #endif #ifdef ULTIPANEL // #define NEWPANEL //enable this if you have a click-encoder panel #define SDSUPPORT #define ULTRA_LCD #ifdef DOGLCD // Change number of lines to match the DOG graphic display #define LCD_WIDTH 20 #define LCD_HEIGHT 5 #else #define LCD_WIDTH 20 #define LCD_HEIGHT 4 #endif #else //no panel but just lcd #ifdef ULTRA_LCD #ifdef DOGLCD // Change number of lines to match the 128x64 graphics display #define LCD_WIDTH 20 #define LCD_HEIGHT 5 #else #define LCD_WIDTH 16 #define LCD_HEIGHT 2 #endif #endif #endif // default LCD contrast for dogm-like LCD displays #ifdef DOGLCD # ifndef DEFAULT_LCD_CONTRAST # define DEFAULT_LCD_CONTRAST 32 # endif #endif // Increase the FAN pwm frequency. Removes the PWM noise but increases heating in the FET/Arduino //#define FAST_PWM_FAN // Temperature status leds that display the hotend and bet temperature. // If alle hotends and bed temperature and temperature setpoint are < 54C then the BLUE led is on. // Otherwise the RED led is on. There is 1C hysteresis. //#define TEMP_STAT_LEDS // Use software PWM to drive the fan, as for the heaters. This uses a very low frequency // which is not ass annoying as with the hardware PWM. On the other hand, if this frequency // is too low, you should also increment SOFT_PWM_SCALE. //#define FAN_SOFT_PWM // Incrementing this by 1 will double the software PWM frequency, // affecting heaters, and the fan if FAN_SOFT_PWM is enabled. // However, control resolution will be halved for each increment; // at zero value, there are 128 effective control positions. #define SOFT_PWM_SCALE 0 // M240 Triggers a camera by emulating a Canon RC-1 Remote // Data from: http://www.doc-diy.net/photo/rc-1_hacked/ // #define PHOTOGRAPH_PIN 23 // SF send wrong arc g-codes when using Arc Point as fillet procedure //#define SF_ARC_FIX // Support for the BariCUDA Paste Extruder. //#define BARICUDA //define BlinkM/CyzRgb Support //#define BLINKM /*********************************************************************\ * R/C SERVO support * Sponsored by TrinityLabs, Reworked by codexmas **********************************************************************/ // Number of servos // // If you select a configuration below, this will receive a default value and does not need to be set manually 84 3D Metal-Plastic Printer // set it manually if you have more servos than extruders and wish to manually control some // leaving it undefined or defining as 0 will disable the servo subsystem // If unsure, leave commented / disabled // //#define NUM_SERVOS 3 // Servo index starts with 0 for M280 command // Servo Endstops // // This allows for servo actuated endstops, primary usage is for the Z Axis to eliminate calibration or bed height changes. // Use M206 command to correct for switch height offset to actual nozzle height. Store that setting with M500. // //#define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1 //#define SERVO_ENDSTOP_ANGLES {0,0, 0,0, 70,0} // X,Y,Z Axis Extend and Retract angles #include "Configuration_adv.h" #include "thermistortables.h" #endif //__CONFIGURATION_H 85 3D Metal-Plastic Printer Appendix C Arduino Software // // // // // // // Inkjet System Code This code is based off of Nihcolas C Lewis’s DIY Printer Project :http://www.thingiverse.com/thing:8542 Portmanipulation tutorial:http://tronixstuff.com/2011/10/22/tutorial-arduino-port-manipulation/ Ardiuno Mega port layout: http://forum.arduino.cc/index.php?topic=52534.0 This program will Loop infinitly. Once compiled and loaded onto the Arduino, if connected the ink will begin to spary. The cartridge was turned on and off using a physical switch. The physical switch can be removed and the Arduino can be used to turn on and off the voltage to the cartriges safely through the optocoupler (this is part of the future work of this project). //Initiallizaion of constants const int PortA = 37; const int PortB = 36; const int PortC = 35; const int PortD = 34; const int Num_Nozzles = 12; //Change value based on how many nozzles want to be used void setup() { DDRC = DDRC | B1111; pinMode(PortA, OUTPUT); pinMode(PortB, OUTPUT); pinMode(PortC, OUTPUT); pinMode(PortD, OUTPUT); } void loop(){ // while(1){ for( byte i = 0; i < Num_Nozzles; i++){ byte nozzle = i; //Turn nozzle (i) on PORTC = nozzle; //Send nozzle byte value to PORTC delayMicroseconds(5); //5 microseonds on //Turn nozzle (i) off PORTC &= ~nozzle; delayMicroseconds(1); //Delay of at least 1 microseond off between firing of a single nozzle } delayMicroseconds(500); // Ensures that there is approximatly 800 microsecond between the firing of a single nozze } } 86 3D Metal-Plastic Printer Appendix D HFSS Results Fig. D.1: PLA Substrate and Copper Patch Resonant Frequency 87 3D Metal-Plastic Printer Fig. D.2: PLA Substrate and Copper Patch Smith Chart 88 3D Metal-Plastic Printer Fig. D.3: PLA Substrate and Copper Patch Radiation Pattern 89 3D Metal-Plastic Printer Fig. D.4: PLA Substrate and Copper Patch Gain Pattern 90 3D Metal-Plastic Printer Fig. D.5: ABS Substrate and Copper Patch Resonant Frequency 91 3D Metal-Plastic Printer Fig. D.6: ABS Substrate and Copper Patch Smith Chart 92 3D Metal-Plastic Printer Fig. D.7: ABS Substrate and Copper Patch Radiation Pattern 93 3D Metal-Plastic Printer Fig. D.8: ABS Substrate and Copper Patch Gain Pattern 94 3D Metal-Plastic Printer Fig. D.9: PLA Substrate and Silver Patch Resonant Frequency 95 3D Metal-Plastic Printer Fig. D.10: PLA Substrate and Silver Patch Smith Chart 96 3D Metal-Plastic Printer Fig. D.11: PLA Substrate and Silver Patch Radiation Pattern 97 3D Metal-Plastic Printer Fig. D.12: PLA Substrate and Silver Patch Gain Pattern 98 3D Metal-Plastic Printer Fig. D.13: ABS Substrate and Silver Patch Resonant Frequency 99 3D Metal-Plastic Printer Fig. D.14: ABS Substrate and Silver Patch Smith Chart 100 3D Metal-Plastic Printer Fig. D.15: ABS Substrate and Silver Patch Radiation Pattern 101 3D Metal-Plastic Printer Fig. D.16: ABS Substrate and Silver Patch Gain Pattern 102