Overmolding Services: Soft Touch, Hard Performance

Enhance grip and functionality with our professional overmolding services. We specialize in TPE overmolding on plastic and soft-touch overmolding for medical tools and consumer electronics, creating a permanent chemical bond between materials.
Macro-Detail

What is Overmolding?

Overmolding (also known as two-shot or multi-shot molding depending on the machine setup) is a specialized injection molding process where a single part is created using two or more different materials in combination.

Typically, the first material (the substrate, usually a rigid plastic like PC or ABS, or a machined metal part) is molded or placed into the tool. The second material (the overmold, usually a soft-touch elastomer like TPE or TPU) is then injected over, around, or through the substrate to form a chemical or mechanical bond.

Material-Boundary
Rigid-Substrate

The Jucheng Precision Tooling Advantage

The greatest risk in overmolding is “flashing”—where the soft overmold material bleeds over the edges of the rigid substrate, ruining the aesthetic and function.

This is entirely prevented by extreme mold precision. Because Jucheng operates an in-house tool room with 25+ high-end 5-axis CNC machines, we machine our overmold cavities with zero-tolerance shut-offs. Combined with our 35+ advanced injection presses, we deliver crisp, perfect boundary lines on every part.

Why Engineers Specify Overmolding

Beyond aesthetics, overmolding solves critical functional challenges in product design without the need for secondary adhesives or gaskets.

Waterproofing (IP67/IP68)

By overmolding a soft elastomer directly onto a rigid housing, you create a permanent, seamless, built-in seal that prevents water and dust ingress, eliminating failure-prone manual gaskets.

Ergonomics & Grip

Adding a soft-touch TPE or silicone layer to surgical tools, power tool handles, or consumer devices drastically improves user comfort, safety, and wet/dry grip performance.

Shock & Vibration Absorption

Encasing sensitive electronic housings or industrial components in a layer of TPU absorbs impact energy, passing rigorous drop tests and extending the lifespan of the product.

The Science of Chemical Bonding

For overmolding to succeed without mechanical interlocks (undercuts), the substrate and overmold materials must be chemically compatible to fuse at the molecular level during injection.

Overmolding with TPE (Elastomer)

Thermoplastic Elastomer (TPE) is the most common soft-touch material. Here is its chemical compatibility:
  • Substrate: ABS

Excellent Bond

  • Substrate: PC (Polycarbonate)

Excellent Bond

  • Substrate: PC/ABS Blend

Excellent Bond

  • Substrate: PP (Polypropylene)

Good Bond (Specific TPE required)

  • Substrate: POM (Delrin)

Poor (Requires Mechanical Lock)

Overmolding with TPU & LSR

For extreme durability or medical applications, we overmold with TPU or Liquid Silicone Rubber (LSR).
  • TPU over ABS/PC

Excellent Bond

  • LSR over PC

Excellent Bond (Requires Primer or Self-Adhesive LSR)

  • LSR over Medical Stainless Steel

Excellent (Requires Primer)

Ensure perfect adhesion between TPE/TPU and your substrate.
Check Bonding Compatibility →

Proven Overmolding Applications

Our overmolding services ensure high chemical bonding strength without the need for adhesives. From silicone overmolding on plastic to TPU injection molding company solutions, we provide waterproof overmolding that meets IP68 standards.
Surgical-Instrument

Medical Devices & Surgical Tools

We overmold medical-grade, sterilizable silicone or TPE onto rigid stainless steel or PEEK substrates. This provides surgeons with non-slip, ergonomic grips essential for precision procedures, fully compliant with ISO 13485 hygiene standards.
Rugged-Device

Rugged Electronics & Wearables

For industrial scanners, outdoor GPS devices, and smartwatches, we overmold shock-absorbing TPU onto rigid PC/ABS housings. This not only passes extreme drop tests but creates a seamless IP68 waterproof barrier without internal O-rings.
Automotive-Bracket

Automotive Sealing & NVH

Under IATF 16949 guidelines, we overmold durable elastomers onto rigid automotive brackets and connectors. This integrates Noise, Vibration, and Harshness (NVH) dampening and permanent fluid sealing directly into the structural component.

Ready to Optimize Your Product's Feel and Function?

Our tooling engineers will analyze your 3D CAD to ensure proper material bonding, shut-off angles, and mechanical interlocks. Get a free DFM report and quote today.
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