Low Injection Pressure Overmolding

Low pressure overmolding refers to the process of applying a second material over a base substrate using low injection pressure. Unlike traditional overmolding that uses high-pressure systems to force materials into molds, low-pressure overmolding uses reduced pressure to create a more controlled, precise result. The low pressure allows for the use of sensitive components, like electronics or delicate parts, without risking damage during molding. It is a versatile process used to combine two different materials, typically in applications where flexibility, protection, or aesthetics are desired. The low injection pressure ensures that the materials flow smoothly and uniformly around the base component, creating a strong bond while protecting the underlying structure.

The low-pressure overmolding process combines two main operations: placing a component inside a mold and then encapsulating it with a secondary material injected at low pressure. This technique supports the production of complex shapes, allowing the softer material to adhere securely to the substrate while maintaining the original form and function of both layers. During molding, the overmolding material is heated and directed into the mold cavity, where it surrounds the inserted substrate. Because the injection pressure is low, the substrate is protected from distortion, resulting in a strong, visually appealing final product.

Substrate Placement: The base component, whether metal, plastic, or sensitive electronics, is carefully positioned within the mold cavity,and heated in preparation for molding.

Mold Insertion: The component to be protected is placed into one half of the mold. The other half of the mold is closed to create a space around the component. Electronic components or parts that need encapsulation are inserted into the mold cavity. Loading time is typically 5-10 seconds.

Overmolding: A low pressure molding machine gently pumps the liquified thermoplastic into the mold cavity until it's filled. Molten material is injected into the mold at low pressure. Continuous injection pressure is applied to compensate for shrinkage during cooling.

Low-Pressure Injection: A secondary material, such as thermoplastics, elastomers, or silicone compounds, is gently injected around the substrate at reduced pressure.

Cooling & Solidification: The injected material is allowed to cool, forming a secure and durable bond between the two materials.

Part Ejection: Once the piece is fully solidified, it is removed from the mold, ready for use or testing.

Thermoplastics: These plastics, such as polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC), are widely used in low-pressure overmolding due to their flexibility, low cost, and ease of processing.

 

Elastomers: Materials like thermoplastic elastomers (TPE) and rubber are often selected for their flexibility and ability to create soft, tactile surfaces in consumer products or medical devices.

 

Engineering Plastics: Stronger materials like polycarbonate (PC), nylon (PA), and polyoxymethylene (POM) are used when high performance and durability are required, especially in automotive or industrial applications.

Strong Material Integration – The overmolded layer bonds seamlessly with the base material, eliminating the risk of detachment.

Flexible Design Options – The internal structure of overmolded components can be freely designed to meet diverse requirements.

No Secondary Processing Needed – The process eliminates the need for additional finishing steps, improving overall production efficiency.

Enhanced Look and Feel – Finished parts feature a smooth surface, attractive appearance, and comfortable touch.

Protection of Sensitive Parts – With its reduced injection pressure, the process safeguards delicate internal components, lowers the chance of damage, and minimizes scrap rates.

AUTOMOTIVE

The Low-Pressure Moulding process plays an important role in the protection of electronics and sensors for all automotive applications.

MEDICAL

Overmoulding of components for medical devices enables improved aesthetics, added functionality, brand identification, and increased value.

ELECTRONICS

Overmoulding protects & strengthens electronic assemblies, electrical and electronic components, PCB's, circuits, connectors and wires.

ELECTROMOBILITY

Electromobility has evolved rapidly in recent years and has become central to the industry.

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