Views: 0 Author: Site Editor Publish Time: 2025-06-12 Origin: Site
LSR is supplied as a two-part system (A + B components) that must be mixed precisely before molding.
✔ Storage – A/B components are stored in temperature-controlled tanks to prevent premature curing.
✔ Metering & Mixing – A 1:1 ratio is maintained using high-precision pumps, followed by dynamic mixing.
✔ Degassing – Vacuum removal of air bubbles ensures defect-free parts (critical for medical applications).
Equipment Needed:
Precision metering units (±1% accuracy)
Static or dynamic mixers
Vacuum degassing systems (optional for high-end applications)
Unlike thermoplastics, LSR requires cold injection into a hot mold for vulcanization.
1️⃣ Clamping
The mold is heated to 120–200°C (depending on the LSR grade).
A cold runner system prevents curing in the feed channels.
2️⃣ Injection
LSR’s low viscosity (similar to water) allows injection at low pressure (50–150 bar).
Needle-valve nozzles prevent material leakage ("drooling").
3️⃣ Curing (Vulcanization)
The LSR cures in 10–60 seconds, forming a durable, flexible silicone network.
Critical Machine Requirements:
LSR-specific injection molding machines
Temperature-controlled molds (±1°C accuracy)
Cold runner systems (minimizes material waste)
Due to LSR’s softness, careful handling is required to avoid deformation.
✔ Ejection – Automated robots or gentle ejection systems prevent part damage.
✔ Post-Curing (Optional) – Some parts undergo secondary curing (150–200°C) for enhanced properties.
✔ Quality Control – 100% inspection for defects, dimensional accuracy, and biocompatibility.
✔ Sterile Packaging – Cleanroom packaging ensures compliance with ISO 13485 standards.
| Challenge | Solution |
|---|---|
| Air bubbles | Micro-venting (0.01–0.03mm vents) |
| Flash (excess material) | Ultra-tight parting lines (<5µm) |
| Sticking to mold | Nickel-PTFE coating or mirror polish |
| Inconsistent curing | Uniform mold heating (oil circulation) |
Material: USP Class VI LSR
Mold: 32-cavity cold runner mold
Process: 160°C mold, 30 sec cure time
Post-Processing: Plasma treatment for hydrophilicity
Key Requirement: Leak-proof, autoclavable
Solution: High-precision molds with zero flash
Micro-Molding – For ultra-small components like microfluidic chips.
Multi-Material Molding – Combining LSR with rigid plastics (e.g., ergonomic grips).
Smart Molding – IoT sensors for real-time process monitoring.
LSR injection molding is a highly specialized process that demands precision in material handling, mold design, and curing control. As medical devices become more advanced, manufacturers must adopt automation, tighter tolerances, and smarter process controls to stay competitive.
Are you working on an LSR medical project? Let us know your challenges in the comments!
