LSR (Liquid Silicone Rubber) injection molding (also known as LIM – Liquid Injection Molding) is an advanced thermoset rubber molding process specifically designed for producing high-precision, flexible, and durable silicone parts. Unlike traditional solid silicone compression molding or thermoplastic injection molding, LSR uses low-viscosity, two-component (A/B components, typically in a 1:1 ratio) liquid silicone rubber material that cures rapidly through platinum-catalyzed addition crosslinking.
Process Flow Overview:
- Metering & Mixing: Dedicated pumps precisely meter Part A (base polymer + fillers) and Part B (catalyst), with optional color paste added. The materials are thoroughly blended in a static mixer to ensure uniformity.
- Injection Molding: The mixed compound is kept cold (10–20°C) to prevent premature curing, then injected under high pressure through a cold-runner system into a heated mold (mold temperature typically 170–200°C).
- Rapid Curing: Heat triggers the crosslinking reaction, completing solidification in just seconds to tens of seconds, forming a fully elastic part.
- Demolding: Thanks to LSR’s softness, parts are usually demolded manually or automatically without ejector pins. This allows greater mold design flexibility, supporting complex geometries, thin walls (0.2–0.5 mm), undercuts, and insert molding.
Key Advantages of LSR Injection Molding:
- High Precision: Low viscosity ensures excellent filling of intricate cavities, tight tolerances, and smooth surface finish.
- Fast Cycle Times: Quick curing delivers high production efficiency, ideal for medium to high volumes (thousands to millions of parts).
- Superior Material Properties: Temperature resistance from -50°C to 250°C, biocompatibility, aging resistance, non-toxic, odorless—meets food-grade and medical-grade standards.
- Eco-Friendly & Efficient: Minimal waste, full automation capability, and reduced labor costs.
Wide Applications include medical devices (catheters, valves, mask components), baby products (pacifiers, teethers), automotive seals, electronic waterproof components, kitchenware, and other premium sectors.
We specialize in custom LSR injection molds and production, equipped with imported machinery, precision cold-runner tooling, and support for fast prototyping (samples in as little as 15 days), high-clarity/transparent/medical-grade materials.
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