A Comprehensive Guide to Silicone Liquid Injection Molding

Materials Used in Liquid Injection Molding

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Silicone is the primary material used in Liquid Injection Molding (LIM), known for its flexibility, durability, and resistance to environmental factors. There are various types of silicone, each suited to specific applications:

Liquid Silicone Rubber (LSR): This is the most common silicone used in LIM, typically platinum-cured, making it biocompatible and highly durable. It’s widely used in medical devices and instruments due to its safe and long-lasting properties.

Fluoro Liquid Silicone Rubber (F-LSR): Incorporating fluorine, F-LSR enhances chemical resistance, making it ideal for automotive parts and small precision components.

Design and Manufacturing Considerations

When designing products for silicone liquid injection molding, several key factors should be considered:

Shrinkage: Unlike thermoplastics, liquid silicone rubber has minimal shrinkage within the mold but can shrink up to 3% post-mold during curing.

Venting: Proper venting is crucial to avoid air entrapment that can compromise the molding process. Complex designs might require in-mold vacuum systems to manage air pockets effectively.

Hot Tearing: Extracting the silicone component from the mold is a delicate process to prevent hot tearing. Collaborating with an experienced LIM manufacturer can mitigate this risk.

The Silicone Liquid Injection Molding Process

Creating parts with Liquid Silicone Rubber (LSR) involves several key steps:

Preparation and Mixing: The process begins with a metered dosing unit that delivers two components (Part A and Part B) to a static mixer. One component contains the platinum-based catalyst, and mixing them creates a homogeneous suspension that cures only when both parts are combined.

Injection Molding Machine: The machine comprises injectors, metering units, supply drums, mixers, nozzles, and mold clamps. It injects the silicone into the mold under pressure. The machine is kept cool to prevent premature curing until the silicone reaches the heated mold, where it sets into its final shape.

Mold Venting and Vacuum: Proper venting or the use of an in-mold vacuum is necessary to eliminate bubbles or leaks, ensuring a flawless final product. Cleanroom environments are often required, especially for medical device production.

Prototyping with Liquid Injection Molding (LIM)

Prototyping with LIM silicone is advantageous, especially in the final stages of product development:

Testing and Finalization: Prototyping allows for thorough testing and refinement of the product before full-scale production. Prototypes made from LIM silicone provide a realistic representation of the final product’s performance.

Flexible Prototyping Options: Earlier stages of prototyping may use 3D printing, aluminum molds, or casting silicone for cost-efficiency and flexibility. However, LIM prototypes offer superior functionality for final validation.

Why Choose us for Liquid Injection Molding and Medical Device Manufacturing?

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Founded in 2008, YJCPlymer excels in custom manufacturing solutions, particularly for medical devices, utilizing extensive expertise in liquid injection molding. Here’s why you should partner with us:

Experience and Expertise: With decades of experience, we deliver exceptional product component manufacturing, leveraging the best practices in LIM to create top-notch medical devices efficiently.

Product Range: We produce a variety of medical accessories, including medical silicone masks, hearing aids, medical air valves, etc., and these products have customized options.

Innovative Approach: Our model—design, develop, deliver—ensures high-quality, creative product development and manufacturing solutions. We continually adopt the latest technologies in LIM, thermoplastic molding, micro molding, compression molding, and transfer molding.

Quality Assurance: Certified with ISO9001 and IATF16949, our robust Quality Management System (QMS) guarantees that you receive products of the highest standards.

Partnering with us means leveraging our expertise and innovative approach to ensure your products meet the highest quality and performance standards, saving you time and money in the process.