ASTM D955-21
Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics

Standard No.

ASTM D955-21

Release Date

2021

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM D955-21

Scope

1.1 This 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. 1.2 This test method covers shrinkage measurements at 24 and 48 hours. 1.3 This 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. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are given for information only. 1.5 This 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. 1.6 This 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.

ASTM D955-21 Referenced Document

• ASTM D3641 Standard Practice for Injection Molding Test Specimens of Thermoplastic Molding and Extrusion Materials
• ASTM D4066 Standard Classification System for Nylon Injection and Extrusion Materials (PA)
• ASTM D4549 Standard Classification System and Basis for Specification for Polystyrene and Rubber-Modified Polystyrene Molding and Extrusion Materials (PS)*， 2021-07-01 Update
• ASTM D4703 Standard Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or Sheets
• ASTM D4976 Standard specifications for polyethylene plastic molding and extrusion materials*， 2024-04-21 Update
• ASTM D5947 Standard Test Methods for Physical Dimensions of Solid Plastics Specimens
• ASTM D618 Standard Practice for Conditioning Plastics for Testing*， 2021-07-15 Update
• ASTM D6778 Standard Classification System and Basis for Specification for Polyoxymethylene Molding and Extrusion Materials (POM)
• ASTM D6779 Standard Classification System for and Basis of Specification for Polyamide Molding and Extrusion Materials (PA)*， 2023-03-15 Update
• ASTM D788 Standard Classification System for Poly(Methyl Methacrylate) (PMMA) Molding and Extrusion Compounds
• ASTM D883 Standard Terminology Relating to Plastics*， 2024-02-01 Update
• ASTM E2935 Standard Practice for Evaluating Equivalence of Two Testing Processes*， 2021-06-01 Update
• ASTM E456 Standard Terminology for Relating to Quality and Statistics
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ISO 293 Plastics — Compression moulding of test specimens of thermoplastic materials*， 2023-02-21 Update
• ISO 294-1 Plastics - Injection moulding of test specimens of thermoplastic materials - Part 1: General principles, and moulding of multipurpose and bar test specimens
• ISO 294-3 Plastics — Injection moulding of test specimens of thermoplastic materials — Part 3: Small plates
• ISO 294-4 Milling cutters mounted on centring arbors having a 7/24 taper; Fitting dimensions; Centring arbors

ASTM D955-21 history

• 2021 ASTM D955-21 Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics
• 2008 ASTM D955-08(2014) Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics
• 2008 ASTM D955-08 Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics
• 2000 ASTM D955-00 Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics
• 1989 ASTM D955-89(1996) Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics