Silicone injection molding parts

Definition and Properties of Silicone Material

Silicone rubber is a high-polymer elastomer with a siloxane backbone. Its main types include Liquid Silicone Rubber (LSR) and High Temperature Vulcanized silicone (HTV).

• Liquid Silicone Rubber (LSR): Through the injection moulding process step by step, a static mixer combines components A and B in precise ratios and injects the material into the mold for curing within 30–60 seconds. It is ideal for mass production of plastic injection components.

• High Temperature Vulcanized (HTV) Silicone: Granular material is mixed in a twin-screw kneader, then transferred to molds. Curing takes 3–5 minutes, suitable for small-batch or complex medical device injection molding prototypes.

Silicone maintains over 300% elongation and 1–3% shrinkage between -60°C to 200°C. It resists UV and chemical corrosion, is non-toxic and odorless, and meets both food-grade and medical-grade standards—making it ideal for precision, durable plastic injection components and medical device injection molding parts.

Core Process Flow – Silicone-Based Injection Moulding Process Step by Step

1. Material Preparation and Dosing

   • LSR: Components A and B, plus additives, are mixed in a 1:1 ratio via static mixers.

   • HTV: Granular silicone is kneaded and heated in a twin-screw mixer.

2. Temperature-Controlled Delivery

   • Temperature across barrels and feed lines must remain stable (±1°C) to prevent premature crosslinking.

3. High-Pressure Injection

   • Under pressures of 500–5000 psi, material is injected into molds with precise control to ensure plastic injection components are free from voids or flash.

4. Curing Under Pressure

   • Mold temperature: 80–200°C for LSR, 150–180°C for HTV.

   • Holding time: 30–60 seconds for LSR, 3–5 minutes for HTV, ensuring complete curing.

5. Demolding and Post-Processing

   • Parts are removed by ejector pins or robots, followed by secondary vulcanization, deburring, cleaning, and sterilization—ensuring each medical device injection molding and plastic injection components part meets quality standards.

Equipment Setup and Quality Control

To meet the high standards of medical device injection molding and plastic injection components, JSJM is equipped with:

• LSR Injection Machines: High-precision dosing pumps, static mixers, and closed-loop temperature control systems for full traceability across the injection moulding process step by step.

• HTV Mixing and Injection Lines: Twin-screw mixers and plunger injection units suitable for small-batch custom or complex prototype runs.

• Cleanroom and In-Line Inspection: ISO Class 7 cleanrooms combined with vision systems and temperature/pressure sensors ensure real-time quality control during medical device injection molding.

• Automated Handling and Packaging: Robotic part removal and automatic packaging avoid contamination and improve efficiency.

Typical Applications – Medical Device Injection Molding & Plastic Injection Components

• Medical Device Injection Molding

  • Products like baby pacifiers, catheter seals, and respiratory mask gaskets benefit from silicone’s low toxicity, low allergenicity, and resistance to chemical sterilization. Complies with ISO 10993 and FDA biocompatibility standards.

• Plastic Injection Components

  • Used in automotive seals, electronic buttons, wearable device keys, and kitchenware gaskets. These products feature ±0.1mm precision, excellent tactile feel, minimal tolerance, and high surface finish—reducing secondary processing costs.

    Future Trends and Challenges

    With growing demand for miniaturization and multifunctionality, Silicone Injection Molding is evolving toward higher precision (±0.01mm) and shorter cycles (<20 seconds). Industry trends also include:

    • Eco-friendly, low-temperature curing formulations

    • Improved flow characteristics for complex mold designs

    • Full automation and flexible manufacturing

    • Integration with additive manufacturing

    we filmed a demo video in our medical device injection molding workshop showing the production of a silicone baby pacifier.

    Conclusion & Call to Action

    This article has thoroughly explained the properties and types of silicone materials, the injection moulding process step by step, equipment setup, quality assurance, applications, process comparisons, and emerging trends. JSJM offers a complete solution for your medical device injection molding and plastic injection components needs with advanced LSR/HTV lines and strict quality systems. Contact JSJM today to begin your efficient, stable silicone injection molding journey!