ISO 294-4:2018 - Plastics -- Injection moulding of test specimens of thermoplastic materials -- Part 4: Determination of moulding shrinkage
This document 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.
Moulding shrinkage as defined in this document 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.
Moulding shrinkage as defined in this document represents the so-called free shrinkage with unrestricted deformation of the cooling plates in the mould during the hold period. It is considered, therefore, as the maximum value of any restricted shrinkage.