Overmolding Insert-Molding

Custom Overmolding and Insert Molding Services

Yinuo Mold provides custom overmolding and insert molding services for plastic components, metal insert parts, soft-touch products, electronic housings, handles, connectors, and functional assemblies. These processes are widely used when a molded part needs better grip, sealing, structural strength, assembly function, or integrated metal features.

We support mold design, material selection, trial molding, low-volume production, and mass production based on customer drawings, 3D models, insert requirements, material compatibility, tolerance needs, surface finish requirements, and final product application.

What Is Overmolding?

Overmolding is a molding process where one material is molded over another material or substrate. It is commonly used to combine rigid plastic with soft TPE, TPU, rubber-like materials, or another compatible plastic material.

This process can improve product grip, comfort, sealing, impact resistance, appearance, and functional performance. Typical overmolded parts include handles, grips, electronic housings, protective covers, seals, buttons, tool components, and consumer product parts.

What Is Insert Molding?

Insert molding places a metal or functional insert into the mold before plastic injection. The plastic material is then molded around the insert to form an integrated component.

Common inserts include threaded brass inserts, stainless steel inserts, steel pins, terminals, bushings, magnets, shafts, electrical contacts, and other pre-formed components. Insert molding helps reduce secondary assembly, improve strength, and create reliable functional plastic parts.

Overmolding and Insert Molding Parts We Can Support

• TPE overmolded handles and grips
• Plastic parts with threaded brass inserts
• Metal insert molded plastic components
• Electronic connector housings
• Consumer electronics plastic housings
• Automotive plastic components
• Industrial equipment plastic parts
• Home appliance plastic components
• Soft-touch overmolded covers and protective parts
• Custom insert molded assemblies

Materials for Overmolding and Insert Molding

Common rigid plastic materials include ABS, PC, PP, nylon, POM, and other engineering plastics. Common overmolding materials include TPE, TPU, and other soft-touch materials depending on bonding requirements and application needs.

For insert molding, common insert materials include brass, stainless steel, steel, aluminum, and other metal components. Material selection depends on strength, bonding, flexibility, chemical resistance, heat resistance, appearance, cost, and end-use environment.

Metal Insert Molding

Metal insert molding is often used when plastic parts require threads, electrical contacts, reinforcement, positioning features, or stronger assembly points. By molding plastic directly around the insert, the part can achieve better structural integration and reduce manual assembly steps.

For threaded inserts, insert position, thread size, insert depth, pull-out strength, torque resistance, and surrounding plastic wall thickness should be reviewed before mold making.

TPE Overmolding

TPE overmolding is commonly used to create soft-touch surfaces, non-slip areas, protective layers, sealing edges, and comfortable grips. It is widely used in handheld products, electronics, tools, automotive parts, and consumer products.

To achieve stable overmolding results, material compatibility, bonding strength, overmold thickness, gate location, mold temperature, shrinkage, and part structure should be evaluated during design and mold development.

Design Considerations

Overmolding and insert molding require careful design review before tooling. Important factors include material compatibility, insert positioning, wall thickness, bonding area, undercut structure, gate location, shrinkage, parting line, flash control, and assembly requirements.

Customers are encouraged to provide 2D drawings, 3D files, material requirements, insert drawings, assembly requirements, and expected production quantity so that our team can review mold feasibility and manufacturing risks.

Quality Control for Insert Molded and Overmolded Parts

Quality control starts from drawing review, insert verification, material confirmation, and mold structure review. During trial molding and production, we check insert position, bonding condition, dimensional accuracy, appearance, flash, deformation, thread quality, and assembly fit.

For parts with threaded inserts or functional inserts, additional inspection can be arranged based on project requirements, such as insert depth check, thread gauge inspection, pull-out review, torque review, and assembly testing.

Typical Applications

• Consumer electronics components
• Electronic connector housings
• Industrial equipment parts
• Automotive plastic components
• Home appliance components
• Tool handles and grips
• Plastic parts with threaded inserts
• Custom functional assemblies

Request Overmolding or Insert Molding Quote

Send us your 2D drawings, 3D files, insert drawings, material requirements, quantity, tolerance notes, and surface finish requirements. Our team will review your project and provide a suitable overmolding or insert molding solution for prototype review, low-volume production, or mass production.