What is Overmolding?
Overmolding is a molding process that combines multiple materials to form a single component or a complete product. Typically, this entails one material being partially or fully covered by subsequent materials during the molding process.
To perform this process, plastic injection molders need specialized equipment. Specifically, they need unique injection molding
machines that are equipped with two or more barrels. This is needed to allow the injection molder to insert two (or more) materials
at a time during the molding cycle.
Now you may be wondering why plastic overmolding is performed. The answer is simple — it's done to protect the first material or to reinforce the component or product as a whole. We will discuss this in-depth later on.
What Materials are Used in Plastic Overmolding?
One of the materials that can be used in this process is, of course,
plastic. Common resins include (but are not limited to):
ABS (Acrylonitrile Butadiene Styrene)
PMMA (Polymethyl methacrylate)
HDPE (High-density polyethylene)
The point of plastic overmolding is to bring together various materials,
so aside from plastics, there are dozens of other options to choose from.
This includes things like rubber and metal. For example, you can use a
combination of rubber and softer polymer or thermoplastic — the possibilities
But, material selection for this process can be tricky, so we at Richfields
follow a strict compatibility chart when helping you pick out your overmolding
materials. This ensures that the resins and additional materials you select
are both chemically and thermally compatible and the best fit for your application.