• Why Use Foam Injection Molding ?

    China has started ban of the production and sale of cars using traditional fuels. At present, Nissan, BAIC, Volvo, Changan Automobile and other car companies have announced their schedule of phasing out fuel vehicles and move towards of development of new electric vehicle.  However, subjected to the mileage of electric vehicles, lightweight issue has become one of the tops ones that needs to be addressed urgently by vehicle manufacturers. Therefore, Micro-foam injection molding technology technology is more and more widely used.     What is Foam Injection Molding? Injection Foam Molding is a low-pressure process where molten resin is injected with nitrogen gas or a chemical blowing agent. The resin is then shot into the cavity, without overfilling or packing it out. The blowing agent or gas then expands to push the molten resin to the extremities of the cavities. As the part cools, the internal pressure of the foaming action takes up the internal shrinkage and reduces sinks over ribs or heavy cross-sections.  …

  • 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
  • Top 10 Tips on How to Fix Injection Overmolding Defects

    When it comes to Overmolding injection molding, the most common two defects that frustrate we see is flash and two plastic material not sticking tightly. What is overmolding injection then? It is a process when one material being is molded over a second material.The base layer is molded first and the additional plastic layer(s) are molded over and around the original part – resulting in a single, finished product.   What are the defects of overmolding and tips on how to fix them? Defect 1.: substrate part deformed This happens because the substrate part is too thin and it gets deformed under high temperature during the process of secondary molding. Besides, if the overmolding area is too thick and narrowly long, the shrinkage force of soft plastic will lead to the “bump”  or arch deformation of the substrate as well Suggestion:check gate position and add strengthening rib to the substrate part.   Defect 2.:…

    Injection molding process October 8, 2019
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