Compression set
Laboratory > Mechanicals
Compression set | |
The compression set is the residual deformation of a material after the elimination of an applied compression stress. For good performance in many applications, compression settings should be low. A low compression set value indicates that a material recovers much of its original height after compression and release of compression force. The compression set test is used to determine the ability of elastomeric materials to maintain elastic properties after prolonged compression stress. You have been exposed to a compression effort for a set period of time. This test is useful for applications where the elastomers would be in a constant state of pressure / release. Test procedure: The specimen is maintained in a compressed state for a specified period of time at a specific temperature, after which the compressive force is eliminated, and the sample is allowed to recover at room temperature for 30 minutes. The thickness of the original sample is measured. The sample is placed between the spacers and the compression device. The sample is compressed to 25% of its original height, using spacers to measure compression accurately. Within two hours of assembly, the compression device is placed in an oven at a specific temperature for 22 hours and 70 hours. 30 minutes before measuring the final thickness. In method A, the compression set is the difference between the original thickness and the final thickness of the sample, expressed as a percentage of the original thickness. In method B, the compression set is expressed as the difference between the original thickness and the final thickness of the sample as a percentage of the deflection to which the sample was subjected. Sample size: There are 2 sizes of cylindrical disc samples: Type 1 The thickness is 12.5 mm +/- 0.5 mm Type 2 The thickness is 6.0 mm +/- 0.2 mm The principle on which they are based is the execution of tests with deformations imposed on the samples and the predetermined environmental conditions, to evaluate the elastic return at the end of the test. The percentage value of compression deformation is obtained by the following expression: Cs = (h iniziale-h finale) / (h iniziale - h compressa)% | |
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