• How to fix defects on double injection molding

    This article mainly discusses some of the molding defects that can occur in a part during the process of double injection molding, and ways to fix and avoid them.    Flash Description –2nd material penetrating between 1st material and its’ It observed frequently where 1st material shrinkage is big and cooling time for 1material is too long. It is mainly due to too fast shrinking of 1stmaterial. Optimizing holding pressure & Cooling time to get min shrinking of 1stmaterial till before 2nd shot Select less shrinkage ratematerial for 1st Changing design as preventive Rainbow Description – Because of too high melt temperature or shear, 1st molded material remelt and flow with 2nd § Solution   Lower 2nd material melt temperature or minimize Use low melt resin or low viscosity material as 2nd Changing the sequence of material.( Clear – 1st shot, Opaque- 2nd shot) Washout Description – Because of too high melt temperature or shear,…

    Mold making, Uncategorized January 11, 2020
  • What is two shot injection molding?

    Two shot injection Molding, also called over-molding multi- component or 2K Injection molding, employs separate injection points for each material in a sequential process. After initial portion material or component is molded, the core half of the mold holding the part is rotated to another, cavity where a second resin is injected.  Below is a simple diagram to illustrate theory of twin shot injection molding.     There are 3 types of two shot injection molding.   Co-Injection Molding: Sequential injection into the same core / One material as the skin , one as the core of the products. Materials can be from the same type and/or be different internal /core.     Multi-Color Injection Molding: Part are same plastic material but usually different Material bond each other, but clearly separated.     § Multi-Material Injection Molding: Partmade of different plastic materials. Materialbond but usually clearly separated. Twin shop injection molding is easy to understand, but it’s…

    Mold making December 21, 2019


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