Silicone Overmolding

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Silicone Overmolding| Custom Silicone Products

Silicone overmolding is typically performed using a two-part liquid silicone rubber (LSR) material that is injected into a mold. The LSR material is then cured to form a solid, flexible layer that adheres to the substrate, such as plastic or metal. The liquid silicone rubber then bonds with the substrate material to create a strong, integrated part. The process can be performed using either a cold or hot runner system, depending on the specific requirements of the application, and is widely used in various industries, including medical, automotive, and electronics, to improve the durability and functionality of products.

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Silicone Overmolding Products

Silicone Overmolding Process

Silicone overmolding process involves the use of two materials: a substrate material and a silicone rubber material. The substrate material can be made of various materials such as plastic, metal, or fabric. The silicone rubber material is injected onto the substrate material using a liquid injection molding machine.


The first step in the process is to prepare the substrate material. The substrate material is cleaned and then coated with a release agent to prevent the silicone rubber from sticking to it. The release agent also helps to ensure that the silicone rubber adheres properly to the substrate material.

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The next step is to prepare the silicone rubber material. The silicone rubber is mixed with a catalyst and then injected into the liquid injection molding machine. The injection molding machine heats the silicone rubber to a high temperature and then injects it onto the substrate material.

Once the silicone rubber has been injected onto the substrate material, it is allowed to cool and cure. The curing process can take several seconds depending on the thickness of the silicone rubber layer. Once the silicone rubber has cured, the part is removed from the mold and any excess silicone rubber is trimmed off.

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Advantages and Disadvantages of Silicone Overmolding

Silicone overmolding has numerous advantages, however, there are also some disadvantages that need to be considered.




1. Excellent Sealing Effect

Silicone overmolding creates a seamless, one-piece design. This eliminates the need for additional fasteners or adhesives, which can weaken over time and compromise the integrity of the protective layer. Additionally, silicone overmolding also offers excellent sealing properties. The silicone rubber material can be molded to fit tightly around other parts, creating a strong seal that prevents leaks or contamination.



2. Durability: 

Silicone rubber is a highly durable material that can withstand extreme temperatures, and UV radiation. This makes it an ideal choice for applications that require high levels of durability and reliability.



3. Design Flexibility:

Silicone overmolding allows for design flexibility, as it can be molded into various shapes and sizes. This makes it ideal for use in applications where custom shapes and sizes are required. The process also allows for the creation of complex shapes and designs, which can improve the aesthetic appeal of products.


4. Cost Effective Process

Silicone overmolding can help to reduce manufacturing costs by eliminating the need for additional assembly steps. This is because the process allows for the creation of multi-component parts in a single step, can eliminate the need for separate assembly steps and reduce the number of components required for each product, and reducing the risk of defects.



1. High Cost:

Silicone overmolding can be more expensive than other molding processes due to the cost of the silicone material and the complexity of the process.


2. Limited Material Options: 

Silicone overmolding is limited to the use of substrate material to be temperature resistant, which may not be suitable for all applications.


3. Longer Lead Time:

Silicone overmolding can have longer lead times due to the complexity of the process and the need for specialized fixtures or jigs.


4. Limited Color Options

Silicone material has limited color options, which may not be suitable for applications where color is a concern.


Applications of Silicone Overmolding

Silicone overmolding is an effective process for protecting products from damage and wear. Its ability to create custom shapes and designs, along with its high level of durability and resistance to environmental factors, make it an ideal choice for a wide range of applications.


Medical Industry

Silicone overmolding is widely used in the medical industry due to its bio-compatibility and durability. Medical devices, for example, catheters, require a protective covering that can withstand harsh environments and frequent use. Silicone overmolding provides an excellent solution for these devices, as it can create a protective layer that is both flexible and durable. Additionally, silicone overmolding can be used to create custom grips and handles for surgical instruments, making them more comfortable and easier to use.

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Automotive Industry

The automotive industry is another area where silicone overmolding has found a wide range of applications. It is used to create various parts such as seals, gaskets, and silicon lenses that require flexibility, durability, and resistance to high temperatures. Silicone overmolding can also be used to create custom grips for steering wheels and gearshifts, providing better comfort and control for drivers.

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Consumer Electronics Industry

Silicone overmolding is also widely used in the consumer electronics industry to create protective covers, waterproof and shock-absorbing components for electronic devices. The process provides a soft and flexible cover that protects the device from water, scratches, drops, and impacts.

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Silicone Overmolding Factory

Silicone overmolding is an incredibly versatile and durable molding technique that offers several advantages over other molding techniques. Its ability to produce complex parts with varying levels of hardness, durability, and sealing properties make it ideal for use in a wide range of applications across various industries.

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YEJIA specializes in manufacturing silicone overmolding products for over a decade. Our experts are highly experienced in silicone overmolding with various materials, and we have an in-house molding making team. For now, we have over 10,000 square meters of silicone molding workshop, and our factory has been certified by ISO9001, ISO14001, ISO13485, and IATF16949. If you're looking for a reliable factory for silicone overmolding, look no further than YEJIA. Contact us today to learn more about our capabilities and how we can help you with your next project.