Technology Knowledge

What is Insert Molding and How does it work

In the simplest terms, injection molding heats the pellet plastic and feeds it into a mold. Insert molding uses the same injection molding process, but adds a step: another material, such as metal or plastic, is inserted into the mold and the plastic is injected to form around it. Instead of assembling parts by hand, insert molding allows one component to be integrated with another for strength, durability, and manufacturing speed.

Insert molding results in stronger, lighter, and more compact parts. It is also more cost effective. While mold making can be expensive, it is a one-time process to complete if it is done correctly. On the other hand, the manufacture and assembly of products is very labor intensive over a long period of time. In the long run, insert molding ends up being more cost effective than higher assembly costs.

To the uninitiated, insert molding is often confused with two-pin molding and overmolding. However, there are some differences between them. Double shot (or multi – material) molding is to inject two different materials into the mold at the same time. It is commonly used in electronics, for example, where silicone or plastic keys are shot onto another type of plastic or metal contact. An overmolding injects plastic into a mold and then casts another plastic on top of the first plastic.