The Process of Overmolding with Silicone Rubber:

The LSR overmolding process entails injecting liquid silicone rubber (LSR) onto a pre-existing substrate or finished component, creating a cohesive multi-material product. This involves placing a thermoplastic part or metal substrate into the LSR injection mold during the molding process, resulting in the formation of a dual-material component.

The LSR overmolding process consists of the following steps:

  1. Positioning a pre-molded plastic part or a metal/other substrate in the mold cavities before LSR injection.
  2. Closing the mold, allowing the injection of LSR to fill the cavities and overmold the plastic or metal part, yielding the final component.

Overmolding vs. 2-Shot Molding:

Both overmolding and the 2-shot processes involve integrating two substrates during molding to create a single, multi-substrate component.LSR Overmolding entails molding an LSR substrate over a pre-placed metal mass or plastic part, providing versatility in substrate combinations for the resulting multi-substrate component.In a 2-shot molding process, both materials are molded simultaneously in a single process and machine, ensuring superior bonding through cavity-to-cavity alignment and precise placement.

Benefits of LSR Overmolding:

Liquid silicone overmolding provides a distinct advantage in manufacturing by allowing the incorporation of non-plastic substrates, such as steel, into the injection molding process. This method stands as the sole means of integrating materials beyond thermoplastic substrates and LSRs in injection molding.

Key Advantages of LSR/Plastic Overmolding:


  1. Dual Material Benefits:Overmolded components showcase a combination of characteristics and benefits from both materials, offering features like rigidity, flexibility, sealing, and insulation.


  1. Incorporation of Non-Plastic Substrates:Overmolding is uniquely capable of introducing materials beyond traditional thermoplastics and LSRs into the injection molding process.


  1. Cost and Time Efficiency:Directly molding silicone onto metal or plastic substrates eliminates the need for secondary post-molding assembly processes, resulting in cost and time savings for the complete assembly.


  1. Design Flexibility:The inclusion of silicone rubber enhances the properties of parts, making them waterproof, airtight, and more resistant to shocks and vibrations.


  1. Quality Assurance:The precision and process controls inherent in the LSR molding process ensure the production of high-quality, securely-bonded parts.

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