Sometimes more than one plastic is needed to manufacture a part. Either two types of material, two colors, or both. When this Is required, co-injection may be the solution. Co-injection is the process in which two separate materials are used to create a product. The substrate is the first material and the over-mold or second shot finishes the part.

Co-Injection as a general term can denote different processes. Atlantis specifically uses rotary co-injection. This technology allows both materials to be injected in two halves of the mold simultaneously. While the substrate is being injected in the top half of the mold, the second shot is being injected in the bottom half of the mold. The top half is injected through the normal sprue nozzle and the co-injection is delivered via a side or top mounted sprue nozzle.



 Co-injection can be a cost-effective way of manufacturing since both processes can be performed at the same time, eliminating the need for a secondary over-molding process. There can be big material cost savings and lighter weight parts, as well as efficient machine functionality performing dual functions. Not all mold injectors can offer this capability. Co-Injection machines cost 25-30% higher than standard injection molding machines and finding a skilled tool designer/maker can be difficult.

Markets & Applications

 Atlantis provides co-injection molding in various markets and applications.

Examples include:

  • Automotive-Trims and Interior Components

  • Plumbing- Handles and Components

  • Appliance-Door Panels, Handles

  • Housewares & Consumer- Cups