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Shrinkage Rate and Mold Temperature in Plastic Injection Molding

模型製作, 模型生產, 治具製作廠商, 模具製作廠商, 測試治具製作, 產品模型製作, 模型製作公司, 塑膠模型製作, 模型 翻模, 公仔模型製作, 公仔生產, 客 製 化模型 公仔, 樹脂公仔製作, 矽膠模具製作, pvc模型製作, 金屬模具製作, 模具製作廠商, 簡易模具製作, 塑膠模具製作流程, 矽膠模具製作, 模具開發流程, 模具設計, 塑膠模具製作流程, 模具加工流程, 汐紫模型, 3d列印代工推薦, 3d列印矽膠模具, 橡膠3d列印, 3d列印翻模, 矽膠 翻模 代 工, 3D 列印 代工 學生, 光固化代印價格, 3d列印模型, 3d列印模型製作, 3d列印公仔, 3d列印圖檔製作, 3d列印廠商, 大型3d列印代工

Shrinkage Rate and Mold Temperature in Plastic Injection Molding

Introduction

When your product enters the injection molding stage, whether using rapid tooling or traditional mass production molds, the underlying physical principles apply. Among these, shrinkage rate and mold temperature are two key factors that determine the dimensional accuracy and quality stability of the finished product. Understanding these two parameters will help you understand the professionalism of the injection molding process.

What is shrinkage rate?

Shrinkage rate is a physical property of the plastic material itself. When the plastic material is heated to a molten state and injected into the mold, it naturally shrinks in volume during the cooling and solidification process.

Different plastic materials have different shrinkage rates. For example, commonly used ABS plastic has a shrinkage rate of approximately 0.5%, while highly crystalline engineering plastics like POM (polyethylene methyl methacrylate) can have a shrinkage rate as high as 2%.

To ensure the final product’s dimensions perfectly match your design drawings, experienced engineers will pre-design the mold dimensions for shrinkage compensation based on your selected plastic material during the initial mold design phase. This means the mold cavity is intentionally made slightly larger than the target dimensions to precisely offset the shrinkage of the material as it cools.

Why is mold temperature important?

Mold temperature is a critical parameter that must be precisely controlled during the injection molding process. It refers to the surface temperature of the mold cavity during the injection process.

Each plastic material has its optimal processing temperature range, encompassing both the temperature of the heating pipe and the temperature of the mold itself. Complex cooling circuits are designed within the mold to precisely control the mold temperature during production.

The correct mold temperature ensures that the molten plastic flows optimally, filling every corner of the mold cavity and cooling at the appropriate rate, resulting in the best possible finished product appearance, dimensional stability, and mechanical strength. This requires professional setting and adjustment by experienced technicians based on the material properties and product structure.

Conclusion

In summary, shrinkage and mold temperature aren’t adjustable options; rather, they are physical properties determined by the very nature of the plastic material you choose. A professional manufacturing partner will factor these complex variables into the mold design and production parameter setting phases early in the project, performing precise calculations and controls to ensure that every injection-molded part consistently meets your desired quality standards.