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What is
Overmolding?

Need overmolded parts that are truly custom? You have come to the right place. HLH delivers high-quality, on-demand injection molding for prototypes and production parts.

Simply put, the overmolding process lets you combine multiple materials into one part. One material, usually a thermoplastic elastomer (TPE/TPV), is molded onto a second material, which is often a rigid plastic. Think about your toothbrush handle where the single piece has both rigid and rubbery components. It’s a great way to make plastic parts perform and look better. For a complete list of our thermoplastic elastomer and rigid plastic material choices, please see our injection molding capabilities page.

Overmolding Design Tips

Wall thicknesses between 0.060" to 0.120" (1.5 mm-3 mm) generally provide the best bonding.

Keeping radii between 0.020" or 0.5mm minimum in corners reduces localized stresses.

If the part requires the use of thick TPE sections, they should be cored out to minimize shrinkage problems, reduce the part weight and lower cycle time.

Avoid deep or un-ventable blind pockets or ribs in your design.

Use gradual transitions between wall thickness to reduce or avoid problems with flow (back fills, gas traps, etc.)

The TPE/TPV should be less thick than the substrate to prevent warpage, especially if the part is flat, long, or both.

Overmolding needs mechanical or chemical bonding to the substrate, so your overmold material choices should enable this.

Applications for OVERMOLDING

BABY PRODUCTS

Baby products such as toys and furniture are more appealing to children when they are colorful and have interesting shapes.

AUTOMOBILE INDUSTRY

Insert injection molding is best known for its unmatched production capabilities from thousands to millions of identical parts.

AUTOMOBILE INDUSTRY

Electronic parts are made safer for consum-ers and more durable by insulating electron-ic components in plastic.

Injection molding materials

Injection molding uses a huge range of plastics, making it ideal for many applications across nearly every industry. we can source thousands of materials on request.

Acrylonitrile Butadiene Styren (ABS)

Polymethyl Methacrylate (PMMA)

Polycarbonate (PC)

Polyethylene (PE)

Polypropylene (PP)

Polyamide 6 (PA6)

Polyether Ether Ketone (PEEK)

Polyoxymethylene (POM)

Injection molding surface finishes

SPI surface finishes:We offer any type of SPI surface finish, such as A-1, D-2 or D-3.

VDI surface finishes:VDI 3400 Surface Finish (commonly known as VDI surface finish) refers to the mold texture standard set by Verein Deutscher Ingenieure (VDI), the Society of German Engineers. This is mainly processed by EDM machining, producing fine to coarse matte finishes.