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Machinery, Plastics, Electronics Analytical solutions in the laboratory
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News August 2014
Unlocking Sources of Failure in Polymer Materials Polymers are widely used in the automotive industry for the cost effective production of weight-optimized components. Thermal analysis makes it possible to ensure the quality and stability of these components.
Understanding the composition and physical properties of a material helps to address and rectify possible failures. Conclusions can be drawn from material and thermal analysis experiments. Polymer applications are so varied that a comprehensive knowledge of its behavior becomes crucial.
The following two applications, carried out using Differential Scanning Calorimetry (DSC) and Thermomechanical analysis (TMA) respectively, illustrate in which way failed parts can be characterized and which processing and physical property conclusions can be drawn from the measurements.
Polymers in the automotive industry One common application of polymers in the automotive industry is sealing. The quality standard is very demanding: Changing processing conditions might cause crystallization. This means that the polymer seal shrinks above a certain temperature causing failure. Seals in contact with solvents are another common source of failure among vehicle components.
Heating curves of thermoplastic seals The first example illustrates the analysis of two semi-crystalline thermoplastic seals using METTLER TOLEDO’s DSC2. The diagram shows DSC heating curves of the two materials. The “Bad” seal failed when the temperature reached about 150 °C, whereas the “Good” seal performed satisfactorily. DSC analysis revealed distinct differences between the
Polymers Characterization
Figure 1: “Good/Bad” components failure analysis
two materials. The “Bad” sample exhibited a glass transition at about 145 °C immediately followed by a crystallization process. In contrast, the “Good” sample showed just the glass transition at about 155 °C and no signs of crystallization. Since crystallization causes shrinking, the “Bad” material failed to meet the quality criteria. The different behavior demonstrated by the two seals is caused by differences in processing conditions; the bad seal had been cooled too quickly. As a result of this, the material did not have enough time to crystallize completely.
Figure 2: Compatibility measurement of a polymer in contact with a solvent
Compatibility of polymers & solvents The second experiment shows a typical example of how polymer and solvent compatibility can be measured using a mechanical technique, such as TMA/ SDTA1. To measure mechanical changes as a function of temperature, the sample was first placed in the oven for two minutes at 30 °C and the initial thickness measured. The furnace was then opened and the glass vessel filled with toluene at same temperature.
The probe measured the increase in sample thickness through swelling due to solvent absorption. As observed, it swells by about 30 % in the first ten minutes. These insights help R&D departments to develop polymer materials that are of the highest quality for the manufacture of optimum components for our vehicles. METTLER TOLEDO’s high-tech thermal analysis instruments provide the answers to material behavior and sources of failure. Author: Matthias Wagner Materials Characterization Product Manager
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Publisher Mettler-Toledo AG Laboratory Division Im Langacher CH-8606 Greifensee, Switzerland Production LAB Division Marketing Global MarCom Switzerland www.mt.com/lab-segmentnews Subject to technical changes. © Mettler-Toledo AG 08/14 Printed in Switzerland.
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Custom Solution For Filtered Particulates Determination Particulate matter in diesel exhaust gases is determined gravimetrically. A custom hardware/software combination is helping UK engine manufacturer Perkins find greater accuracy and convenience for this common application. Diesel exhaust gases have to be determined for particulate matter during engine testing. To achieve this, particulate matter is collected on filters over a defined time period and the concentration determined by differential weighing. However, filters have a low weight and large surface area making them particularly susceptible to environmental influences and the equipment used for weighing must be highly accurate in order to measure the minute amounts of particulate matter collected. Revving up accuracy Ultra-micro balances are required for the pre- and back-weighing of each filter in order to determine the tiny amounts of particle matter present. With 0.1 µg readability, the XP2U ultra-micro balance is perfect for measuring the smallest weight difference. The freestanding antistatic kit is the perfect addition to this setup as it eliminates any electrostatic charge to guarantee accurate results.
Secure process Process security and traceability are also key aspects when determining the particle content in each filter. Connecting the XP2U to LabX laboratory software ensures a high level of process security through precisely followed filter-weighing procedures. LabX handles all data and calculations automatically, including any necessary adjustments necessary for environmental factors. All results and relevant regulatory parameters, such as date and balance ID, are stored in a secure database to provide full traceability.
Filter Weighing with Excellence Plus XP micro balance.
Particulate Matter Determination
XP2U ultra micro balance
Automated door opening.
Author: Walter Krebs Senior Product Manager Micro Balance
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Micro U-ionizer device rapidly neutralizes electrostatic charges.
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Oil Content Determination The Right Oil Content for Mechanic Motor Pieces The oil content in rotor’s spindle motors is critical to PC hard-drive’s storage performance. The quality standards of the hard-drive industry necessitate in-production testing of rotors weighing less than 1.5 mg with an uncertainty of 1 %. A challenging task simplified by XPE205 analytical balances at a leading spindle motor manufacturer. The hard disc drive industry, manufacturing 522 million units per year, demands the best quality and uptime to satisfy its precision-parts suppliers. A Southeast Asian specialized manufacturer, with more than 40 years of experience in producing small precision motors, supplies spindle motors to the three largest hard disc drive manufacturers. This is a key hard disc drive component for PCs worldwide. A sensitive equation Maximum throughput is critical to meeting these volume requirements. However, working with such small parts brings
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specific quality control challenges, particularly when it comes to weighing. The exact weight of oil applied to each rotor that comes down the production line is essential to the smooth spinning of each disc but production time is also critical for optimizing manufacturing operations. Each rotor is weighed four times prior to final assembly to determine: • Rotor weight. • Weight after filling the top of the rotor with oil. • Weight after filling the bottom of the rotor with oil. • Weight after spinning to measure residual oil.
Productivity and quality guidelines require the company to use balances capable of stabilizing within 2.5 seconds for weights less than 1.4 milligrams and with a weighing error of only 1 %. Four balances robust enough for nearcontinuous use are required per manufacturing station. Additionally, while providing accuracy, speed and reliability, the balances must also simultaneously reduce the possibility of hand pain or repetitive strain injury by being ergonomic and, therefore, comfortable and safe to operate.
Hard disc drive with spindle motor in the center of the magnetic disk.
XPE205 analytical balance
A high quality and reliable set-up To meet these varied, stringent manufacturing requirements, the company recently outfitted its production area with METTLER TOLEDO XP205 analytical balances. In addition to installing these analytical balances into their lines, they procured three additional units for backup during preventative maintenance. They also secured a service contract and had METTLER TOLEDO provide expert training so that operators are able to deal with any simple balance problems that may arise in order to maximize productivity.
This complete product and service package, including analytical balances capable of meeting minute tolerances and quick settling, support, training, extra units and spare parts, is helping to keep the production floor itself spinning smoothly. Today, this leading spindle motor manufacturer continues to meet the hard disc drive industry’s quality demands with maximum uptime and remains a reliable precision-parts supplier. Author: Simon Taylor, Analytical Balances Product Manager
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Thermal Analysis Productivity Rise in Materials Characterization CANOE, a technology transfer platform covering the entire life cycle of thermoplastic composites, recently decided to equip its premises near Bordeaux with METTLER TOLEDO thermal analysis instruments. Operating in a fast-growing segment, CANOE can now depend on quick, reliable and efficient characterization of materials. Created in 2009 on the initiative of the Regional Council of Aquitaine, CANOE is “a platform for technology transfer and pooling resources aimed primarily at SMEs and SMIs” explains S. Jestin, Design engineer at CANOE. The structure is “young and dynamic, with strong growth potential”, he adds. CANOE offers human and equipment resources to help companies expand in the composites and advanced materials field for all business sectors (transport, renewable energies, etc). CANOE has 5 core activity sectors: use of composites and advanced materials, 6
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extrusion – its historical activity, thin layers, formation and characterization/ NDT of materials. Thermal Analysis: answering specific needs A fast-growing activity and an increasing number of samples to process led CANOE to turn to METTLER TOLEDO’s Thermal Analysis equipment. Previously lacking in-house facilities, the team had been obliged to outsource its analyses, “a waste of time and money”, explains S. Jestin. “In order to take control of deadlines, costs and maintain confidentiality, acquiring our own equipment became a necessity”, he adds.
The solution proposed by METTLER TOLEDO covers a number of techniques: TGA (Thermal Gravimetric Analysis), DSC (Differential Scanning Calorimetry Analysis) and DMA (Dynamic Mechanical Analysis). DSC and TGA are connected to 34-position autosamplers. CANOE’s users have particularly appreciated the sampler arm being designed to a single degree of freedom. This ensures excellent reliability and guarantees very precise positioning of the sample.
Left: Users of MT instruments at CANOE, from left to right: Johan Broustau, Jean-Marie Morvan, Célia Mercader and Simon Jestin. Right: Jean-Marie Morvan, Head of the Characterization and Non-Destructive Testing Department at CANOE.
Massive time savings Automating analyses combined with the possibility of launching up to 34 simultaneously has radically changed processes: with the programming done upstream, it is simply a question of loading up the samples and starting the analysis, which runs automatically. “A massive time saving, given that previously it took around 2 hours to do a single analysis!”. From now on, the operator can take advantage of this “to spend time on other tasks” explains J-M. Morvan, Head of CANOE’s Materials Characterization and Non-Destructive Testing center.
CANOE now controls every stage in the materials characterization chain, a source of real added value for its customers. Without a doubt, “METTLER TOLEDO’s equipment perfectly complements the rest of our mechanical and rheological characterization equipment and has allowed us to hugely increase our productivity and competitiveness!”, assures J-M. Morvan. Author: Laetitia Plesel Marketing/Communication (France)
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Broaden your TA knowledge Sign-up for live and on-demand Thermal Analysis webinars
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Know-How
Don’t Let Electrostatic Charges Influence Your Weighing Results One of the most common problems experienced when weighing dry substances in a laboratory environment is the influence of electrostatic charges, leading to inaccurate weighing results. The new XPE analytical balance offers a unique technology to detect electrostatic forces, measure its influence in the weighing and eliminate them.
StaticDetect™ Built-in StaticDetect technology warns you when electrostatic charges affect the weighing results above your defined threshold.
ErgoClip™ The ErgoClip basket for plastic and glass tubes shields the weighing pan from electrostatic changes. Small tubes also reduce the risk of creating charges.
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FAQ Electrostatic Charges in Weighing 1. What are electrostatic charges? An electrical charge on the balance or vessel to be weighed causes electrostatic forces. Electrostatic forces can alter weighing results either increasing or diminishing the real weighing value. 2. How are electrostatic charges originated? Friction is the most common way that electrostatic charges are generated. However, under climate controlled environments, such as the typical analytical lab, charges are more easily generated and lead to greater source of error. Weighing a small quantity of dry sample into a large glass or polymer vessel will also significantly increase the error of the weighing result. 3. How do they influence weighing results? Electrostatic charges exert forces on the sample to be weighed and the weighing pan, thus causing significant falsification of measurement results. Inaccurate weighing results range from few milligrams up to 100 mg.
Antistatic Kit Attach the Antistatic kit to the analytical balance and eliminate charges without causing turbulences in the weighing chamber.
Download the ‘Electrostatic Charges in Weighing’ whitepaper
www.mt.com/lab-electrostatic-weighing METTLER TOLEDO
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Product Highlight
Enhanced Precision Weighing Delivers Reliable Results Precision weighing suffers sometimes from slow stabilizations, air currents and therefore low repeteability The innovative SmartPan™ on the new XPE precision balances makes it possible to weigh-in with 5 mg readability without the need for a draft shield. SmartPan enables all users to quickly achieve stable weight values and better repeatability, even within the turbulent environment of a fume cupboard.
Enhanced performance SmartPan™ minimizes the effects of air currents on the weighing cell to deliver results up to 50% faster and improve repeatability by 30%. The integrated tray underneath contains spills and is easy to clean.
Compliant results The innovative StatusLight™ terminal lets you see at a glance if you have the green light for weighing: balance calibration and routine tests are up to date, and the balance is level and functioning correctly.
Ergonomic processes Avoid stresses and strains from working for long periods at the balance. Place the terminal on a stand and adjust the tilt to suit your height; the display is easier to read and good posture is maintained.
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The All-in-one Printing Solution Flexible Printing and Labeling The robust P-56 and P-58 universal printers offer a multitude of printing possibilities to help you to eliminate transcription error, speed up your processes and ensure traceability, e.g. continuous printing or sample labeling with barcodes. The P-56 is ideal for simple printouts and for all instruments with embedded applications. The P-58 offers several integrated applications such as time and date, statistics, totaling, formulation and labeling.
Noiseless speed The state-of-the-art direct thermal printing technology in the P-56 and P-58 is clean, vibration-free and exceptionally quiet. With a printout speed up to 100 mm per second, they are extremely fast too.
Flexible documentation Print on continuous paper or continuous self-adhesive labels for full documentation of your results. For fast, easy, error-free sample identification, print labels with all sample information and barcodes.
Durable printouts Properly stored, the archive-grade fadeproof paper will last up to 25 years, and single and continuous labels up to 10. All papers are phenol-free and resistant to plasticizers, oil, fat and water.
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