Similar to ISO 844, ASTM D1621 is a testing standard designed to measure the compressive properties of rigid cellular plastics (i.e. foam). This post is intended to help you understand the basic test procedure and the equipment needed to perform this test with certainty. When you are ready to test your materials to this standard, please refer to the official ASTM D1621 specification.
- Make sure that your samples are the correct size as indicated in the specification.
- Precisely measure the area of each specimen using the method recommended in the specification.
- Center the sample in the compression platens and begin applying load at the indicated rate.
- Make sure that deflection is being recorded either automatically based on crosshead position or manually at 0.5% increments. MTESTQuattro software controller is capable of graphically displaying deflection based on crosshead position in real-time. The system can also be connected to a defectometer to provide more accurate deflection data.
- Continue to apply load until the sample yields or until the sample has been compressed to the percentage of original thickness indicated in the standard.
- Calculate compressive strength using the load amount at which ever point in step four occurs first.