Introduction

Liquid Silicone Rubber (LSR) is a versatile material used in industries ranging from medical devices to automotive components. Its unique properties—such as heat resistance, flexibility, and biocompatibility—make it ideal for precision-molded parts.

But how is LSR manufactured at scale? In this blog, we’ll explore the LSR production line, covering:
✔ Key components of an LSR production line
✔ Step-by-step manufacturing process
✔ Equipment used in LSR molding
✔ Quality control & industry applications

1. Key Components of an LSR Production Line

A typical LSR production line consists of the following systems:

A. Material Handling & Storage

• Silos/Tanks: Store Part A (Base + Catalyst) and Part B (Crosslinker + Additives) separately.

• Chillers & Heaters: Maintain optimal material viscosity (typically 20-40°C).

B. Metering & Mixing Unit

• Precision Pumps: Deliver A and B components in exact ratios (usually 1:1).

• Static/Dynamic Mixers: Ensure homogenous blending before injection.

• Vacuum Degassing: Removes air bubbles to prevent defects.

C. Injection Molding Machine

• Cold Runner System: Prevents premature curing in the injection unit.

• Clamping Unit: Holds the mold under high pressure (50-200 tons).

• Heated Mold (120-200°C): Triggers platinum-catalyzed curing in seconds.

D. Post-Processing & Automation

• De-flashing: Removes excess material (manual or automated).

• Post-Curing Oven (Optional): Enhances mechanical properties.

• Automated Ejection & Conveyor: Transfers finished parts for inspection.

E. Quality Control (QC) Systems

• Vision Inspection: Checks for defects like voids or flash.

• Dimensional Testing: Ensures compliance with CAD specifications.

• Mechanical Testing: Hardness (Shore A), tensile strength, elongation tests.

2. Step-by-Step LSR Manufacturing Process

Step 1: Material Preparation

• Part A (Base + Catalyst) and Part B (Crosslinker) are stored in temperature-controlled tanks.

Step 2: Precision Metering & Mixing

• A metering pump dispenses A & B in the correct ratio.

• A static mixer blends them homogeneously before injection.

Step 3: Injection Molding

• The mixed LSR is injected into a heated mold (120-200°C).

• Curing takes 10-120 seconds, depending on part thickness.

Step 4: Demolding & Ejection

• The mold opens, and parts are ejected (often using robots).

Step 5: Post-Curing (If Required)

• Some parts undergo additional curing (1-4 hrs at 200°C) for optimal performance.

Step 6: Quality Assurance & Packaging

• Parts are inspected for defects, sterilized (if medical-grade), and packaged.

3. Essential Equipment in LSR Production

4. Industry Applications of LSR

✅ Medical: Seals, catheters, respiratory masks (biocompatible).
✅ Automotive: Gaskets, vibration dampers (heat-resistant).
✅ Consumer Electronics: Waterproof seals, keypads.
✅ Baby & Food Products: Bottle nipples, kitchenware (FDA-approved).

5. Advantages of LSR Over Traditional Rubber

✔ Faster cycle times (seconds vs. minutes for thermoset rubber).
✔ No byproducts (cleaner than peroxide-cured silicone).
✔ Superior precision for micro-molded or thin-walled parts.

Conclusion

An LSR production line combines precision metering, automated molding, and strict QC to produce high-performance silicone parts. With applications in medical, automotive, and consumer goods, LSR continues to grow as a preferred material for engineers.

Interested in setting up an LSR production line? Consult with experts to optimize your process for efficiency and quality!