Liquid Silicone Rubber (LSR) Molding: Process, Advantages & Applications
Author: Site Editor Publish Time: 2026-05-25 Origin:
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What is LSR?
Liquid Silicone Rubber (LSR) is a two-component, platinum-catalyzed silicone material that is injected into precision molds under high pressure. Unlike traditional HTV (High-Temperature Vulcanizing) silicone, LSR flows like liquid before curing, enabling extremely high precision and clean production.
LSR vs HTV Silicone: Key Differences
| Property | LSR | HTV Silicone |
|---|
| Viscosity before curing | Liquid, flows freely | Paste-like, requires compression |
| Precision | Very high (±0.01mm achievable) | Medium |
| Production efficiency | Fast cycle (30-90 sec) | Slow (2-5 min cycle) |
| Cleanliness | Excellent (closed injection) | Good (open mold) |
| Medical/Food grade suitability | Best (clean room production) | Good |
| Tooling cost | Higher (precision molds required) | Lower |
| Best for | High-volume, tight-tolerance parts | Large parts, lower volume |
LSR Process Steps
- Step 1: Two-component LSR (Part A + Part B) loaded into injection machine
- Step 2: Platinum catalyst mixed in precise ratio (1:1 typically)
- Step 3: Material injected into heated mold cavity (150-200°C)
- Step 4: Material vulcanizes (cures) in 30-90 seconds
- Step 5: Part ejected, flash removed, inspection
Best Applications for LSR
- Medical devices: Respiratory masks, catheters, baby bottle nipples
- Food processing: Sealing rings for coffee machines, baby products
- Optics: Light guides, lens gaskets
- Automotive: High-precision sensor gaskets, LED sealing
- Electronics: Waterproof enclosures, connector seals
LSR Grades Available
- Standard LSR: General industrial use, -50°C to +230°C
- Food-grade LSR (FDA 21 CFR 177.2600): Direct food contact
- Medical-grade LSR (ISO 10993 / USP Class VI): Healthcare applications
- High tear strength LSR: For products subject to mechanical stress
- Self-adhesive LSR: Bonds to metal/plastic substrates during molding
Design Tips for LSR Parts
- Wall thickness: keep uniform (0.5-3mm typical)
- Draft angle: 1-3° for easy part release
- Gate location: avoid cosmetic defects on visible surfaces
- Parting line: position where flash is hidden from view
- Tolerances: ±0.05 to ±0.10mm for most LSR parts
Anlintech offers LSR molding services with cleanroom production capability. Contact us to discuss your LSR project.
