Proposed Setup Steps Of Turning Machine For Application In

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INTERNATIONAL JOURNAL OF CONTROL, AUTOMATION AND SYSTEMS VOL.4 NO.3 ISSN 2165-8277 (Print) ISSN 2165-8285 (Online) http://www.researchpub.org/journal/jac/jac.html July 2015 Proposed Setup Steps of Turning Machine for Application in Educational Process S. Z. EL-Abdien Department. of Mechanical Engineering, College of Engineering, Taif University, Taif, 888, Saudi Arabia. [email protected] "headstock," which contains the motor and gear train that makes rotation possible. Directly across from the headstock on the lathe is the "tailstock." The tailstock can hold the work by either alive or dead center. Work that is held at both ends is said to be "between centers." Additionally, longer work-pieces may have a "steady rest" mounted between the headstock and tailstock to support the work. Typically work-pieces are cylindrical, but square and odd shaped stock can also be turned using special chucks or fixtures[3]. Lathe cutting tools brought to the work may move in one or more directions. Tool movement on the engine lathe is accomplished using a combination of the lathe's "carriage", "cross slide", and "compound rest"[2,4]. Abstract— In this article educational steps are proposed to prepare and equip cutting machines, specially turning machine to preserve the integrity and safety of students and trainees based on a laboratory experiences. The steps are intended to be useful for carrying laboratory experiments which serve the production engineering courses, or other courses such as materials removal or graduation project course. Keywords— Machine setting-up, Educational Experiments, Workshop. Turning machine, I. INTRODUCTION Lathe is one of the most versatile and widely used machine tools all over the world. It is commonly known as the mother of all other machine tool. The main function of a lathe is to remove metal from a job to give it the required shape and size. The job is securely and rigidly held in the chuck or in between centers on the lathe machine and then turn it against a single point cutting tool which will remove metal from the job in the form of chips. Lathes are manufactured in a variety of types and sizes, from very small bench lathes used for precision work to huge lathes used for turning large steel shafts. But the principle of operation and function of all types of lathes is same [ 1]. Parts ranging from pocket watch components to large diameter marine propeller shafts can be turned on a lathe. The capacity of a lathe is expressed in two dimensions. The maximum part diameter, or "swing," and the maximum part length, or (distance between centers). The general-purpose engine lathe is the most basic turning machine tool. As with lathes, the two basic requirements for turning are a means of holding the work while it rotates and a means of holding cutting tools and moving them to the work[2] . The carriage travels along the machine’s bed-ways, parallel to the work-piece axis. External turning can be broken down into a number of basic operations. "Straight turning" reduces the work to a specified diameter equally along the work’s axis. "Taper turning" produces a taper along the axis of the work-piece. Tapers are produced by either offsetting the tailstock from centerline or by using a "taper attachment." Some short, steep tapers can be obtained by using the compound rest alone. "Contour turning" or "profiling" uses a single-point cutting tool to reproduce a surface contour from a template. This operation has been almost entirely replaced by numerically controlled or "NC" programming [5]. "Forming" uses a cutting tool ground with the form or geometry of the desired shape. This forming tool is advanced perpendicular to the axis of the work to reproduce its shape on the work-piece. Other external lathe operations include "chamfering" to remove sharp edges, "grooving" to produce recesses and shoulders, "facing" to finish the ends of a work-piece, "parting" to cut off finished pieces from the stock, and "thread chasing" with tools to produce the desired thread form. The work may be held on one or by both its ends. Holding the work by one end involves gripping the work in one of several types of chucks or collets. Chucks are mounted on the spindle nose of the lathe, while collets usually seat in the spindle. The spindle is mounted in the lathe's II. TYPES OF LATHES Lathes are manufactured in a variety of types and sizes, from very small bench lathes used for precision work to 32 INTERNATIONAL JOURNAL OF CONTROL, AUTOMATION AND SYSTEMS VOL.4 NO.3 ISSN 2165-8277 (Print) ISSN 2165-8285 (Online) http://www.researchpub.org/journal/jac/jac.html July 2015 huge lathes used for turning large steel shafts. But the principle of operation and function of all types of lathes is same. The different types of lathes include: 1) Speed lathe that which is classified into; a) Wood working, b) Spinning, c) Centering, d) Polishing. 2) Centre or engine lathe which is: a) Be1t drive, b) Individual motor drive, c) Gear head lathe. 3) Bench lathe, 4) Tool room Lathe, 5) Capstan and Turret 1athe, 6) Special purpose lathe which is classified into; a) Whee1 lathe, b) Gap bed lathe, c) Dup1icating lathe, d) T-lathe, 7) Automatic lathe. III. CONTROLLER DEDIGN A simple lathe comprises of a bed made of grey cast iron on which headstock, tailstock, carriage and other components of lathe are mounted. Figs. 1,2 show the different parts of engine lathe or central lathe. The major parts of lathe machine are given as: 1) Bed (guide way), 2) Head stock, 3) Tailstock, 4) Carriage, 5) Feed mechanism, 6) Thread cutting mechanism Fig. 3. illustrates the elements involved in specifications of a lathe [6]. The size of a lathe is generally specified by the following means; 1) Maximum swing over the bed (C), 2) Maximum distance between centers (B), 3) Length of bed (A), 4) Height of centers over the bed (C/2), 5) Maximum swing over the carriage (D). 5) Width of bed. 6 )Morse taper of center. 7) Diameter of hole through spindle. 8) Face plate diameter. 9) Size of tool post 10) Number of spindle speeds. 11) Lead screw diameter and number of threads per cm. 12) Size of electrical motor. 13) Pitch range of metric and inch threads. Fig. 2 Main components of lathe Fig. 3 Specifications of a lathe [6] IV. CUTTING FORCES AND POWER When metal cutting is carried out on the machine tool, the following recommendation are suggested:1- Machine tools with enough power must be selected 2- With known cutting forces, machine tools can be designed to avoid excessive distortion and maintain desired tolerances 3- Engineers can determine if the work-piece will withstand the cutting forces without distortion. 4- The tool holder, work-holding device, and machine tool must be sufficiently stiff to minimize deflections caused by the thrust force so that the tool is not pushed away from the work-piece (reducing depth of cut and causing dimensional inaccuracy) 5- Cutting forces can be measured by mounting on the tool: Dynamometers or Force transducers (piezoelectric crystals) 6- Cutting forces can also be calculated if you know the power consumption of the machine Fig. 1 Main components of a central lathe [6] 32 INTERNATIONAL JOURNAL OF CONTROL, AUTOMATION AND SYSTEMS VOL.4 NO.3 ISSN 2165-8277 (Print) ISSN 2165-8285 (Online) http://www.researchpub.org/journal/jac/jac.html The single point cutting tools being used for turning, shaping, planning, slotting, boring etc. are characterized by having only one cutting force during machining. But that force is resolved into two or three components for ease of analysis and exploitation as shown in Fig. 5, where: Cutting force,Fz acts in the direction of the cutting speed V, and supplies the energy required for cutting. Thrust force,Fy acts in a direction normal to the cutting force. Axial force Fx acts in a direction parallel to the axis of rotation of work-part. Resultant force R resultant of cutting, thrust and axial force. July 2015 4- Make sure the emergency key in the turn-on position. 5- Choose the correct speed corresponding to the workpiece diameter by selection manual speed, shown in Fig.2. 6- Choose the correct machine feed rate corresponding to the depth of cut from the selection manual feed, shown in Fig.2. 7- Choose the suitable depth of cut according to the required surface roughness from cross slide hand wheel, shown in fig.2. 8- Firmly clamping the work-piece on the lathe chuck by chuck key, shown in Fig.2. 9- Make sure the lift chuck key is removed to insure ward off risks. 10- Make sure that variation of work-piece is about its axis to prevent damage of cutting tool and work-piece. 11- Use the tail stock from another side when the overhang length of the work-piece more than three times of the work-piece diameter. 12- Choose the correct cutting tool according to the type of operation such as (facing, grooving, boring or straight turning……). 13- Choose the type of tool, right or left tool. 14- Firmly clamping the cutting tool on the tool post, shown in Fig.2 15- Keep the tool overhang minimum as possible, when supported on the tool post, shown in Fig.2. 16- Check the free load vibration of the work-piece and cutting tool 17- Slowly first touch tool with work-piece by carriage hand wheel or cross slide hand wheel according to the direction of cutting. 18- Take the required depth of cut according to the number of path based on the initial and final diameter of work-piece. 19- Complete the operation according to the working drawing. Fig. 5 Resultant force R in turning process IIV. MECHANICS OF MACHINING In the metal cutting operation the tool is wedge –shaped and has a straight cutting edge. There are two methods in metal cutting, depending upon the arrangement of cutting edge with respect to the direction of relative work-tool motion; a) Orthogonal cutting or two dimensional cutting, b) Oblique cutting or three dimensional cutting. In Orthogonal cutting the cutting edge is arranged perpendicular to the cutting velocity vector V , whereas in oblique cutting , it is set at angle other than 90 degree to the cutting velocity vector which gives an inclination angle (ʎ) [7,8] VI. CONCLUSIONS The proposed setup steps of turning machine for application in educational process had been proposed for educational paper of lab. The best product and safe work can be obtained when this steps are followed. REFERENCES [1] http://www.gitam.edu/eresource/images/Single_point _cutting_tools.pdf. V. MECHANICS OFPROPOSED SETTING-UP STEPS FOR EDUCATIONAL PURPOSES [2] G. Bala Subramanyam, P. Punna Rao, Optimization of Cutting Parameters Using Genetic Algorithm and Particle Swarm Optimization, International Journal Of Modern Engineering Research (IJMER), Vol. 4 , Iss. 6, June, 2014. motor The following are proposed preparatory machine setting up steps performed on a turning machine to result in better machine performance, better cutting capabilities and in addition safe operation :1- Check the dovetail shape and its guide of the cross slide and compound rest, shown in fig. 2. 2- Check the work-piece holder (chuck). 3- Check the guide way of the machine. [3] Pradeep Patokar, Sunil Andhale, Chinmay Patil, Nitin Borkar, Methods to Improve Production Rate in Turning Operation, International Journal of Research in Advent Technol ogy, Vol.2, No.3, March 2014. 32 INTERNATIONAL JOURNAL OF CONTROL, AUTOMATION AND SYSTEMS VOL.4 NO.3 ISSN 2165-8277 (Print) ISSN 2165-8285 (Online) http://www.researchpub.org/journal/jac/jac.html [4] Naresh Kumar Reddy , B.V.Raju , Determination of Optimal Cutting Conditions Using Design of Experiments And Optimization Techniques, International Journal of Engineering Research & Technology (IJERT), Vol. 1 Issue 10, December2012 Technology, Textbook, New Age International (P) Ltd., 2006. [7] Beddoes J. & Bibby M. J. Principles of Metal Manufacturing Processes, Carleton University, Canada. Textbook, 2003. [8] Kalpakgian S. 'Manufacturing Engineering and Technology' Text book Fourth Edition, Wesley 1999. [5] Turning & the Lathe, society of manufacturing engineering, www.ams.org [6] Rajender Singh, Introduction Manufacturing Processes and July 2015 To Basic Workshop 32