Plastic Tensile Test

The tensile testing machine.

Plastic tensile test.

From these measurements the following properties can also be determined. Properties that are directly measured via a tensile test are ultimate tensile strength breaking strength maximum elongation and reduction in area. Astm d 638 tensile test procedure. Din en iso 527.

A tensile test is typically governed via standards and the two most common in the plastics industry are astm d638 and iso 527. This includes astm d638 technically equivalent to iso 527 1 is a testing standard which ascertains the tensile properties of a plastic material. The figure below from quadrant engineering plastic products shows the test geometry. 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.

Pull off speeds up to 20 m s are achieved. Separate tensile test methods are commonly applied to polymer films astm d882 or iso 1184 and elastomers astm d412 or iso 37. 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. Most iso 527 2 testing is performed on a table top universal testing machine.

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. 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. For this test plastic samples are either machined from stock shapes or injection molded. Tensile testing of plastics supplies the data for a sample.

A universal testing machine tensile testing machine is needed to perform this test. In addition the use of direct extension measurement on the specimen is possible allowing informative stress strain diagrams to be generated. Astm d638 is one of the most common plastic strength specifications and covers the tensile properties of unreinforced and reinforced plastics. The high speed tensile test can be performed using drop weight testers or hydraulic high speed tensile testing machines.

This test method uses standard dumbell or dogbone shaped specimens under 14mm of thickness. The tensile test the test measures the force as a function of the strain being applied to the plastic sample. Specimens are placed in the grips of the universal tester at a specified grip separation and pulled until failure.