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ASTM D955-21
Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics
1.1This test method is intended to measure shrinkage from mold cavity to molded dimensions of thermoplastics when molded by compression or injection processes with specified process conditions.
1.2This test method covers shrinkage measurements at 24 and 48 hours.
1.3This method will give comparable data based on standard specimens and can not predict absolute values in actual molded parts with varying flow paths, wall thicknesses, pressure and temperature gradients and process conditions. Differences in mold shrinkage may also be observed among the three specimen geometries described in this test method.
1.4The values stated in SI units are to be regarded as the standard. The values given in parentheses are given for information only.
1.5This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1:This standard and ISO 294-3 are equivalent in the design of specimen D2. This test method is equivalent to ISO 294-4 where Type D2 specimens and the procedure in Appendix X2 are used.
1.6This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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