Plastic shrinkage rate and mold size

Here is the precise technical translation adhering to mold engineering standards:

‌Plastic Mold Design: Shrinkage Considerations‌
Upon finalizing mold structure configuration, detailed design commences including determination of template dimensions, cavity/core sizing, etc. This phase necessitates critical parameters such as ‌material shrinkage rate‌ to establish cavity dimensions. Even with structurally sound mold design, improper parameter selection will yield non-conforming parts.

‌Plastic Shrinkage Mechanism & Influencing Factors‌
Thermoplastics exhibit thermal expansion when heated and contraction upon cooling, with additional volumetric reduction under pressure.

‌Shrinkage Phenomena in Injection Molding‌

1. ‌Molding Shrinkage‌

   • Occurring when molten plastic solidifies in cavity and contracts upon demolding

   
   

2. ‌Post-Molding Shrinkage‌

   • Subsequent dimensional changes after demolding until stabilization, primarily manifested as continued contraction