TEBATE Services

Over Molding Services

Use multiple injections of thermoplastics to manufacture parts for high volume projects to improve consistency, strength and durability.

Overmolding is an injection molding process in which multiple strands of thermoplastic are injected separately to form a single part.

What is Overmolding?

over molding is an injection molding process in which multiple strands of thermoplastic are injected separately to form a single part. The first injection of thermoplastic into the tool or cavity forms the base material before the cladding molding material is injected on, on, or around it. The thermoplastic layers bond as they cool to produce a uniform and highly durable final product. The bonding between substrates depends on the properties of the relevant cladding forming materials.

The substrate can be almost anything: machined metal parts, molded plastic parts, or existing products (such as threaded inserts, screws, or electrical connectors). The substrate, which is the basis of what eventually becomes a single continuous component, is made of different types of chemically bonded (often mechanically interlocked) materials.

Cladding molding materials are usually plastic-based and are usually in the form of pellets. The particles are then mixed with colorants, foaming agents, and other types of fillers. The grain is melted and the resulting liquid is injected into the mold.

Advantage of Overmolding

overmolding can be used to combine similar materials of different colors, and it has many advantages over the traditional assembly process

Better adhesion

Noise & vibration reduction

More compact design

Reduce production cost

Better adhesion

Noise & vibration reduction

More compact design

Reduce production cost

Corrosion protection

Electrically insulated


Basic Guide of Plastic Overmolding

Unlock the potential of your encapsulation molding project with the following injection molding design considerations, including mold details, available materials and colors, and finishing and post-processing options

Design Guide of Overmolding

Right Substrate

The initial component or substrate is the foundation of the overmolded product. The substrate must be able to withstand the overmolding process, and its shape must be compatible with the overmolding material. Common substrate materials include metals, plastics, and composites.

Parting Line

The parting line is the point where the two materials meet. The parting line should be located in a non-critical area of the final product to minimize any visible lines or parting marks.

Wall Thickness

Maintaining uniform wall thickness throughout the part is important to ensure consistent strength and prevent warping or sink marks. Varying wall thickness can cause uneven cooling during the molding process, leading to defects.

Ensure that the wall thickness of the substrate and the thickness of the cladding die are uniform from the beginning of the process. The 0.060″ to 0.120″ (1.5 mm to 3 mm) wall thickness will ensure good adhesion in most cladding applications.


Sharp corners can cause stress concentrations that weaken the part and make it more prone to failure. It’s better to use rounded corners or fillets to distribute stress and strengthen the part.

Draft Angles

Draft angles are angled surfaces that allow the part to be easily ejected from the mold. A minimum draft angle of 1 degree is recommended to ensure smooth ejection and avoid damage to the part.


The gate is the location where the molten material enters the mold. Gates should be located in areas where the overmolded material will flow uniformly and bond well to the substrate. Common gate locations include the edge of the part, the center of the part, or the end of the part.

TEBATE’s Capabilities of Overmolding 

Maximum Part Size

  • 800 x 800 x 400 mm
  • 31.5 x 31.5 x 15.7 in

Minimum Part Size

  • 5 x 5 x 5 mm
  • 0.2 x 0.2 x 0.2 in


  • Standard tolerance:  ±0.005″ (0.127mm)
  • Best achievable tolerance:  ±0.001″ (0.025mm)

Delivery Time

  • As low as 2 weeks for T1 samples
  • After T1 sample approval, lead time for < 10,000 parts is as low as 1 week

Tool validation

  • Standard process is to produce a small set of T1 samples for approval before initiating full production

Maximum Press Size

  • 1200T


  • 1Pcs

Materials of Overmolding 

Most Common Materials

Additives and fiber

Additives and fiber

Acrylonitrile Butadiene Styrene (ABS)

Nylon (PA 6, PA66, PA12)

UV absorbers

Polyethylene (PE)

Polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS)

Flame retardants

Acrylonitrile Butadiene Styrene (ABS)

Nylon (PA 6, PA66, PA12)

UV absorbers

Polyethylene (PE)


Flame retardants

Polypropylene (PP)

Polyurethane (PU)


Polycarbonate (PC)

Polymethyl Methacrylate (PMMA/Acrylic)


High Density Polyethylene (HDPE)

Glass fibers

Low Density Polyethylene (LDPE)

Polystyrene (PS)

Polyvinyl chloride (PVC)


POM (Acetal/Delrin)

Polyethylene Terephthalate (PET)

Thermoplastic Elastomer (TPE)

Thermoplastic Vulcanizate (TPV)

Polyetherimide (PEI)

Polysulfone (PSU)

Surface Finishes of Overmolding 


Surface Roughness Grade


Pantone color matching

A1 – A3

Pad printing

RAL color matching

B1 – B3

C1 – C3

D1 – D3


Q: How much does the injection mold cost?

A. Prices range from a thousand dollars to tens of thousands of dollars, depending on the complexity of the mold you want.

Q: Is injection molding environmentally friendly?

A: Injection molding processes are more environmentally friendly. They attribute it to efficient machines and durable thermosetting polymers that can withstand extreme temperatures. However, this does not mean that injection molding is absolutely safe for the environment. It also releases harmful gases that contribute to the greenhouse effect, but this is well controlled by modern injection molding.

Q: Is there a way to reduce injection molding costs without compromising product quality?

A: Yes, there is! You can do this by reducing or removing unnecessary features such as company logos, textured surfaces, and molded part numbers.