Shrinkage of moulded parts

Total shrinkage of a moulded part comprises the following phenomena, which occur simultaneously  

Only volume shrinkage undergoes changes in time. From the use aspect, shrinkage of a part relates to linear dimensions and is given as a percentage. 

Assuming, as an approximation, that the sum of mould and post-mould shrinkage is a constant, we should always strive towards mould (controlled) shrinkage forming the greatest possible part of the sum. 

Plastic temperature Removal temperature High mould temperature Injection time Distance from gate Shrinkage rises 

Holding pressure Holding time Cycle time Injection pressure Plasticising pressure Injection velocity Shrinkage falls 

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