ODM LSR Molding (Liquid Silicone Rubber) Manufacturers & Products

LSR is a two-component liquid material (1:1 mixing ratio) cured using a platinum-catalyzed addition reaction at high temperatures. It flows easily into complex micro-molds and cures rapidly in automated injection systems. HCR is a high-viscosity clay-like compound that requires labor-intensive compression or transfer molding, has longer cure cycles, and typically utilizes peroxide curing which leaves chemical extractables unless post-baked.

Primerless chemical bonding is achieved by using specialized self-bonding LSR polymers formulated with reactive adhesion promoters (silane coupling agents). During the thermal cure cycle inside the mold (around 150°C–170°C), these agents form covalent chemical bonds with polar functional groups on the surface of engineering plastics (like PA66, PBT, or Polycarbonate) or cleaned metal substrates.

Standard manufacturing tolerances for LSR parts follow DIN ISO 3302-1 Class M1. For high-precision functional features, linear dimensions can be held within ±0.02mm to ±0.05mm depending on part geometry, shrinkage factor (typically 2.0% to 3.0%), and durometer hardness (ranging from 10 Shore A to 80 Shore A).

LSR flash prevention relies on three critical tooling factors: 1) High-grade hardened mold steel (S136 or H13 hardened to HRC 52-56) with precision-ground parting lines (±0.002mm shut-off clearance); 2) Active vacuum de-airing (-0.95 bar) in the cavity prior to injection; and 3) Thermal isolation between the cold runner system (kept cooled at 20°C) and heated cavity plates.

Because LSR is non-abrasive compared to glass-filled thermoplastic resins, LSR steel tooling suffers minimal mechanical wear. A hardened steel LSR mold (e.g., DIN 1.2083 / AISI S136) maintained with proper cold runner seals typically yields a lifespan of 1,000,000 to 5,000,000 injection cycles.