Combine Two or More Materials in a Single Part
What is Overmoulding?
Overmoulding is the process of combining two or more materials in the formation of a single plastic part. Specifically, it involves adding a layer to an already existing component.
Overmoulding is an important value-added secondary process for some plastic injection moulded parts. It can sometimes be necessary for functional or cosmetic reasons.
From a functional point of view, overmoulding can improve handheld parts where comfort and grip are important. Cosmetically, overmoulding can allow for the creation of branding or textual information on a part or where a certain stylistic finish needs to be achieved.
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Overmoulding at RP Technologies
RP Technologies has extensive experience of creating plastic injection mouldings where overmoulding is required as a sub-process. We have created overmoulded components for the automotive, medical and consumer products industries.
This is an example of an overmoulded plastic part which we created for Jaguar Land Rover.
This part is a gasket seal. Without the overmoulding, the part would not adjoin tightly to its object component. The overmoulding allows it to function correctly, adding versatility, strength and grip.
We have also overmoulded parts for products in other sectors, including medical devices, consumer goods, marine and aerospace.
How Does Overmoulding Work?
Overmoulding is the process of combining two or more materials in the formation of a single plastic part. Specifically, it involves adding a layer to an already existing component.
Overmoulding is an important value-added secondary process for some plastic injection moulded parts. It can sometimes be necessary for functional or cosmetic reasons.
From a functional point of view, overmoulding can improve handheld parts where comfort and grip are important. Cosmetically, overmoulding can allow for the creation of branding or textual information on a part or where a certain stylistic finish needs to be achieved.
Material Options for Overmoulded Parts
Overmoulding is suitable for a wide variety of plastic grade material selections. The substrate usually consists of a more rigid, tougher plastic. Typical materials include:
- PPS
- Polycarbonate
- Acrylonitrile Butadiene Styrene (ABS)
- Polyethylene Terephthalate (PETG)
- Nylon
Overmoulding usually utilises TPEs (Thermoplastic Elastomers). These materials have ideal physical properties, characteristics and features for the overmoulding process.
Overmoulding Tools
The success of overmoulding projects relies heavily on precision tooling. At RP Technologies, we design and manufacture tooling in-house to ensure accuracy and efficiency.
Our tooling capabilities mean we can create moulds tailored to the specific requirements of each project. This ensures consistent part quality, shorter lead times and greater flexibility during development.
Overmoulding vs Insert Moulding
Overmoulding and insert moulding both combine materials, but the processes differ in simplicity and application.
- Overmoulding: Involves injecting two shots of material; the first forms the substrate and the second creates the overmould. This allows for additional grip, comfort or aesthetic finishes.
- Insert Moulding: Involves only one shot of molten plastic, which is injected around a pre-fabricated insert. The insert, often metal or another component, needs to be created or provided separately.
Overmoulding is often chosen for ergonomic or cosmetic benefits, while insert moulding is ideal for integrating non-plastic parts directly into a plastic component.
Advantages of Using Overmoulding for Electronics and Medical Devices
Electronics and medical device manufacturers often benefit greatly from overmoulding. Key advantages include:
- Simplified Assembly: The process combines multiple components and functions into a single part, eliminating the need for secondary assembly steps, which reduces labour, manufacturing time and costs.
- Protection: Overmoulding can help safeguard sensitive internal components and delicate pins from accidental damage, vibration and shock.
- Improved safety: Wires, circuits and delicate components can be completely encapsulated, preventing exposure to damage or contamination.
- Ergonomics: Handheld devices benefit from softer grip materials, making them easier and safer to use over long periods.
- Design Flexibility: Overmoulding enables the integration of different colours, textures and shapes, allowing for distinctive product designs that reinforce brand identity and enhance appeal in target markets.
Design Considerations for Effective Overmoulding Projects
To achieve the best results, overmoulding requires careful design planning:
- Material compatibility: Ensuring the substrate and overmould materials bond effectively is essential.
- Part geometry: The design must allow the second material to flow evenly without voids or weak spots.
- Tooling design: Accurate mould tool design ensures reliable repeatability and tight tolerances.
- Function vs appearance: Deciding whether the priority is grip, insulation, strength or cosmetic finish will guide material and process choices.
At RP Technologies, our engineering team works closely with clients at the design stage to ensure overmoulded parts meet all technical and functional requirements.
Prototypes Using Overmoulding
Before moving to full-scale production, many clients require prototypes to test their designs.
RP Technologies specialises in producing low-volume, high-quality prototypes using overmoulding. These prototypes allow manufacturers to:
- Validate product performance in real-world conditions
- Test ergonomics and grip on handheld parts
- Identify potential design improvements early
- Reduce risks before committing to larger scales of production
We can put your plans into action today
Award-winning aluminium tooling, plastic injection moulding, CNC machining, and rapid prototyping. We specialise in fast turnarounds of high quality components.
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