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Tensile Testing of Plastic Thin Film | Equipment for ASTM D882

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Tensile Testing of Plastic Thin Film | Equipment for ASTM D882

Information on tensile testing thin plastic materials, along with machines and equipment for tensile testing plastics, per ASTM D882. Thin Plastic Film Standard Test Procedures Thin plastic is a relative term which ASTM and ISO determined to be plastics that are less than 1mm in thickness. Thin plastic materials are used to create plastic garbage bags, sandwich bags, food containers, electrical wire insulators, pens, and countless other items. Tensile testing of the thin plastic material should be done as part quality control and engineering design efforts. Tensile testing of thin plastic sheets is done to determine how the plastic material stretches, or strains, when pulled by a large load. Mechanical properties of thin plastic sheets such as tensile strength, and elongation are determined for design purposes and product comparison. Tensile strength of plastic sheets is the measure of how a plastic film responds to being pull. For applications that use thin sheet plastic, such as trash bags, tensile strength is a comparable measurement of how much heavy garbage can the bad hold before it breaks. On the other hand elongation of plastic sheet or film used for the garbage bag is the measure of how much the bag will stretch when it is full. Measurements of thin film plastic tensile properties are important to the application which the material is being used. In plastics, there are many stress-strain relationships that can be engineered by changing the composition and manufacturing process of the thin plastic film. Ultimately, the purpose of specific tensile properties of a specific plastic film are meant to meet a product requirement or design specification.

To ensure quality it is important to have testing procedures that are repeatable so that accurate comparisons of tensile properties of thin plastics can be made. Standard Test Method for Tension Testing Plastics and Composites ASTM D882 covers the testing procedures for tensile testing thin plastic sheets and films. ASTM D638 targets thin plastics that less then 1 mm thick. Tensile properties of thin plastics can be determined using two different tests that are defined in ASTM D882. The first test defined by ASTM D882 for tensile testing thin plastic sheet is a tension test using strips of thin plastic with a constant rate of extension test machine. The thin plastics sheets are pulled apart at a constant rate until they break. This method should be used to measure the stress-strain characteristics of plastics as they are pulled from no load to failure. Mechanical properties of thin plastic film determined through method A of ASTM D882 include tensile yield strength, tensile breaking strength, percent elongation, elastic modulus, secant modulus, and energy to break. The second test defined by ASTM D638 is a pendulum tensile test of thin plastics. This test can be used to determine the tensile energy to break (TEB). Recommended Plastic Tensile Testing Equipment Plastic tensile testing, specifically following the practices of ASTM D638, requires the use of a CRE (constant rate of extension) test machine, with a fixed grip and movable grip attached to the CRE loading unit. Plastic tensile tester machines need to be equipped with an extensometer to measure the strain of the plastic with in tension. TestResources testing machines are modular systems that can be built to accomplish any tensile test of plastic. The plastic tensile testing machines we make have advanced feedback controllers for performing a wide variety of motion controlled tests, CRE being one of the most basic. Along with plastic tension testers, we sell grips specifically designed to be self aligning easy to load for tensile testing plastics.