Over molding is currectly molded on third parts , for example: electronic ,strain relief on cable, PCB sensitive components protection. It is non-independent plastic products, we usually give the product is defined as the pre-molding and over molding, as a fact a mold design without lot of differents. The company process in the provision of molded plastic products, at the same time for some components, cable assemblies molding tools. We use the pre and over molds, these encapsulation is usually for final products convenience to use, to ensure the products safety during working.

Over Molding

What is Pre-molding and Over Moldings


  • Premolding

Pre-molding(internal molding) is the first process that some products are usually molded twice. The most commonly used plastic is PE. Of course, base on the customer’s preference is the most important, you can use the same material as the second molding resins, but as a supplier have duty to consider the second material is suitable for the pre-mold, the choices a lot but each plastics temperature and hardness not same (from Shore A 60 ~ Shore A90), so choose not the same plastics to consider the characteristics of the resin itself than considering the needs of customers . Pre mold not only serves to protect the main body but also makes an internal support to the outer mold to reduce the defect rate after the over molded.

  • Over molding

Over molding (external molding) can make customers get a perfect end product, the appearance of the external mold leading by the dimensions of the mold and the pressure of the molding injection machine, also the temperature of the plastics melt is closed related. A precision perfect over mold finished product can effectively match the corresponding parts.

Injection molding machines

Applicated Molding Machine


We currently use vertical (stand) injection molding machine for over molding

  • The mold tool not large, install the mold tool quickly
  • Suitable for metal parts inserted
  • Convenience to put the third parts into the mold