What Is Overmolding?
Overmolding is a molding process in which a rigid plastic substrate is covered with a second, usually softer material in a second molding operation. The soft material (commonly TPE or TPU) is bonded onto the rigid part to create a comfortable grip, seal or protective layer. Overmolding is widely used to improve ergonomics, add two-tone finishes and create water-tight seals without separate assembly.
Overmolding vs Two-Shot Molding
Both processes combine two materials, but overmolding typically molds the soft layer onto a pre-molded substrate in a separate step, while two-shot molding completes both materials in one cycle. Overmolding is often more cost-effective for lower volumes and for designs where the substrate is produced separately, while two-shot molding suits higher volumes with tighter integration.
Common Overmolding Applications
- Power tools — soft-grip handles and impact protection
- Consumer electronics — protective bumpers and button covers
- Medical devices — ergonomic grips and sealing surfaces
- Household products — comfortable handles and non-slip bases
- Industrial equipment — vibration dampening and protective layers
Common Material Combinations
We frequently combine rigid substrates such as PC, ABS, PA and PP with soft materials like TPE and TPU. The substrate material, bond strength and chemical compatibility are reviewed during DFM to ensure a durable bond between the two layers.
Overmolding at D-top Mould
D-top Mould designs and builds overmolding tools for prototype and production volumes. Our process covers DFM review, substrate tooling, overmold tooling, material pairing and trial validation. We support both the initial design and the optimization of existing overmolded parts.
What We Need for a Quote
Send your 2D or 3D drawings, the substrate and overmold materials, expected annual volume and tolerance requirements. Our engineering team will review the design and respond with a quotation within 12 hours.