Overmolding is a process that involves injecting a second layer of plastic over an already molded part, combining two materials into a cohesive and functional product. This technique allows for the addition of insulation, ergonomic grip, or extra protection to the component.
Common examples: video game controllers, blenders, hair dryers, steering wheels, gear levers…
This process is similar to standard injection molding but requires an additional mold and the use of two materials.
Material combinations:
1. Plastic – plastic: Two compatible plastics, often differentiated by color.
2. Plastic – rubber: Enhanced ergonomics for contact surfaces.
3. Metal – plastic: Plastic elements molded over a metal base.
4. Metal – rubber: Improved grip through a soft surface on metal.
It’s essential to verify material compatibility before overmolding, especially when using materials from different families.
Substrate (1st material) | Overmolding (2nd material) | Compatibility | Remarks |
|---|---|---|---|
ABS | TPE / TPU | Good (80-90%) | Natural adhesion |
PC (Polycarbonate) | TPE | Good to excellent (90-95%) | Strong chemical bond |
PA (Nylon) | TPE | Medium to good (60-80%) | May require primer depending on TPE used |
PP (Polypropylene) | Special TPE (PP adhesive) | Medium (50-70%) | Prefer modified TPE for PP |
PE (Polyethylene) | Special TPE | Low to medium (40-60%) | Surface treatment often required |
Metal (aluminum, steel) | TPE / TPU / PA | Variable (30-70%) | Adhesion improved by grooving, inserts, or surface treatments |
PBT | TPE | Medium (50-70%) | Highly dependent on the grade of TPE used |
Our technical sales team is ready to listen to your needs.