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 highly difficult to manage. It requires high levels of technical expertise and attention to detail, and even the smallest mistakes can cost big money, especially in high-volume production scenarios.
Thus it is very critical to find a highly capable supplier with quality scorecards and defined processes to mitigate against flash, flow lines, and short-shots, and contingency plans to expand capacity as your business and your two-shot molding needs grow.
If you have any two shot injection project that require involvement in the early design phase of your part, please contact us at firstname.lastname@example.org for technical assistance.