Plastic Tensile Test

Tensile testing of plastics supplies the data for a sample.

Plastic tensile test. Specimens are placed in the grips of the universal tester at a specified grip separation and pulled until failure. For this test plastic samples are either machined from stock shapes or injection molded. A tensile test is typically governed via standards and the two most common in the plastics industry are astm d638 and iso 527. The figure below from quadrant engineering plastic products shows the test geometry.

The tensile testing machine. Din en iso 527. Tensile tests measure the force required to break a plastic sample specimen and the extent to which the specimen stretches or elongates to that breaking point. Properties that are directly measured via a tensile test are ultimate tensile strength breaking strength maximum elongation and reduction in area.

The test method can be used for testing materials up to 14mm 0 55 in and the material should be in the shape of a dumbbell or dog bone. With the use of plastics being at an all time high it is critical that manufacturers be able to properly gauge the mechanical strength of their materials. The tensile test the test measures the force as a function of the strain being applied to the plastic sample. The high speed tensile test can be performed using drop weight testers or hydraulic high speed tensile testing machines.

A 5kn or 10kn 1125 or 2250 lbf system is most common but as reinforced plastics and composites increase in strength higher capacity units such as 30 or 50 kn systems may be required. This test method uses standard dumbell or dogbone shaped specimens under 14mm of thickness. This guide is designed to introduce you to the basic elements of an astm d638 plastic tensile test including an overview of the equipment software and samples needed. From these measurements the following properties can also be determined.

Astm d638 is one of the most common plastic strength specifications and covers the tensile properties of unreinforced and reinforced plastics. Most iso 527 2 testing is performed on a table top universal testing machine. Astm d 638 tensile test procedure. Tensile testing also known as tension testing is a fundamental materials science and engineering test in which a sample is subjected to a controlled tension until failure.

Tensile tests are used for example in the validation of the chemical resistance of plastics since the results of this test disclose even extremely small changes in the material. This includes astm d638 technically equivalent to iso 527 1 is a testing standard which ascertains the tensile properties of a plastic material. In addition the use of direct extension measurement on the specimen is possible allowing informative stress strain diagrams to be generated.