Plastic Injection Molding · 04
오버몰딩
A soft, rubber-like material molded over a rigid plastic or metal substrate — for grip, comfort, sealing, vibration damping or a second color. We advise the material pairing, build both molds and run the parts, so the bond is engineered rather than hoped for.
TPE · TPU · silicone overmolds
PC · ABS · PA · PP · metal substrates
Chemical bond or mechanical lock
Why Overmold
One part, two materials, no assembly.
The overmold does a job the base plastic cannot — and replaces a glued or snapped-on rubber component with something that cannot fall off.
Grip
Soft-touch surfaces
Comfortable, non-slip handles on tools, appliances, toothbrushes and razors.
Seal
Integrated gaskets
Molded-in seals for water- and dust-resistant enclosures, no separate O-ring to assemble.
Damp
Vibration & impact
Shock-absorbing bumpers and feet on electronics, instruments and automotive parts.
Look
Color & branding
Two-color styling, logos and tactile zones molded in — no painting, no wear-through.
Material Pairing
The bond starts with the right pair.
Some overmold resins bond chemically to the substrate; others need mechanical locks — undercuts, through-holes or a textured surface — designed into the base part. We tell you which in the DFM report.
- Chemical bond
- Mechanical lock needed
- Not recommended
Substrate ↓ / Overmold →
TPE
TPU
Silicone (LSR)
PP soft
PC
lock
---
ABS / PC-ABS
lock
---
PA / Nylon
✓ (PA grade)
lock
---
PP
✓ (PP grade)
lock
PC
lock
lock
lock / primer
lock
How It Works
Two shots, one finished part.
Overmolding can run as a two-station process with a substrate mold and an overmold mold, or in one cycle on our double-injection machines when volumes justify a 2K tool.
Step 1
Design the interface
Wall thickness, undercuts, shut-offs and gate positions set in the DFM report so the soft material stays where it should.
Step 2
Mold the substrate
The rigid base part is molded first in PC, ABS, PA or PP — or a metal part is machined and cleaned.
Step 3
Transfer or rotate
The substrate moves to the overmold cavity — by hand, robot, or a rotating platen on a 2K machine.
Step 4
Shoot the overmold
TPE, TPU or silicone is injected over the substrate; heat and pressure create the chemical bond or fill the mechanical locks.
Step 5
Test the bond
Peel and pull tests on first samples, then color, hardness (Shore A) and dimensions checked on every batch.
Our Work
Soft-touch, silicone and TPU parts.
Overmolded and silicone molded products from our Dongguan plant — consumer, kitchen, personal care and industrial.