A systematic study on the effect of processing conditions on mold shri
nkage was undertaken for seven common thermoplastic polymers. It turne
d out that the holding pressure was always the key parameter. The effe
ct of the melt temperature is slightly less important. Injection veloc
ity and mold temperature do not show a general trend for all polymers.
It was shown that at least for amorphous polymers a simple thermoelas
tic model could describe all experimental results. For semi-crystallin
e materials the model overpredicts shrinkage.