Liquid Silicone Rubber (LSR) moulding is a specialized manufacturing process used to produce flexible, durable, and high-precision rubber parts. It’s widely used in industries like medical devices, automotive, electronics, and consumer products.
🧪 What is Liquid Silicone Rubber (LSR)?
LSR is a two-part platinum-cured elastomer known for:
High flexibility and elasticity
Excellent heat and cold resistance
Biocompatibility (safe for medical and food use)
Chemical and UV resistance
⚙️ How LSR Moulding Works
The process is typically done using injection moulding, but with liquid material:
Material Preparation
Two liquid components (Part A and Part B) are stored separately.
Mixing & Metering
The components are precisely mixed (often 1:1 ratio), sometimes with pigments or additives.
Injection
The liquid is injected into a heated mold cavity.
Curing (Vulcanization)
Heat triggers a chemical reaction that solidifies the silicone.
Demoulding
The finished part is removed—often automatically due to LSR’s flexibility.
🏭 Key Advantages
High precision & consistency (great for tight tolerances)
Fast cycle times (ideal for mass production)
Minimal waste (efficient material usage)
Excellent durability (resistant to extreme environments)
Clean process (important for medical/food-grade products)
⚠️ Challenges
High tooling cost (molds must be very precise)
Complex process control (temperature, mixing ratio, etc.)
Flash control (thin excess material can occur if molds aren’t perfect)
📦 Common Applications
Medical: seals, gaskets, catheters, baby bottle nipples
Automotive: connectors, seals, vibration dampers
Electronics: keypads, waterproof components
Consumer goods: kitchenware, wearables
🔍 LSR vs Solid Silicone (HCR)
Feature LSR HCR (High Consistency Rubber)
Form Liquid Solid
Processing Injection moulding Compression/transfer moulding
Automation Highly automated Less automated
Precision Very high Moderate
💡 When to Use LSR Moulding
Choose LSR when you need:
Complex geometries
High-volume production
Medical or food-grade compliance
Long-term durability in harsh environments
