1 Scope
This part of GB/T 17037 specifies a method of determining the moulding shrinkage and post-moulding shrinkage of injection-moulded test specimens of thermoplastic material in the directions parallel to and normal to the direction of melt flow.
For the determination of shrinkage of thermosets see ISO 2577[2].
Moulding shrinkage as defined in this part excludes the effects of humidity uptake. This is included in post-moulding shrinkage and thus in total shrinkage. For cases when post-moulding shrinkage is caused by the uptake of humidity only, see ISO 175[1].
Moulding shrinkage as defined in this part represents the so-called free shrinkage with unrestricted deformation of the cooling plates in the mould during the hold period. It may be considered therefore as the maximum value of any restricted shrinkage.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of GB/T 17037. For dated references, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 17037.1-1997 Plastics - Injection moulding of test specimens of thermoplastic materials - Part 1: General
principles, and moulding of multipurpose and bar test specimens (idt ISO 294-1:1996)
GB/T 17037.3-2003 Plastics - Injection moulding of test specimens of thermoplastic materials - Part 3: Small plates (ISO 294-3:2002, IDT)
3 Terms and definitions
For the purposes of this part of GB/T 17037, the terms and definitions given in GB/T 17037.1 together with the following apply.
3.1
moulding shrinkage
SM
difference in dimensions between a dry test specimen and the mould cavity in which it was moulded, both the mould and the test specimen being at room temperature when measured
Foreword i
Introduction ii
1 Scope
2 Normative references
3 Terms and definitions
4 Apparatus
5 Procedure
6 Expression of results
7 Precision
8 Test report
