How to Manufacture Silicone Products: HCR, LSR, Extrusion, Calendering & Casting

Thanks to their outstanding safety, durability, and flexibility, silicone products are widely used in daily life, medical devices, automotive, electronics, and industrial fields.

But how can silicone products actually be manufactured?

This article explains five key molding processes — High Temperature Vulcanization (HCR), Liquid Silicone Rubber (LSR), Extrusion, Calendering, and Casting — including step-by-step workflows, example products, and their respective advantages and limitations.

1. High Temperature Vulcanization (HCR, Solid Silicone)

Production Steps:

1. Raw Material Preparation: Using a kneader or open mill, mix solid silicone rubber (HCR) with curing agent, pigments, and additives.
2. Cutting: Cut the mixed silicone into pre-measured blanks according to product weight.
3. Mold Preheating: Heat the metal mold to 150–200℃.
4. Feeding & Clamping: Place the blanks into the mold cavity, close the mold, and apply 10–50 MPa pressure.
5. Vulcanization: Maintain heat and pressure for seconds to minutes until cured.
6. Demolding & Trimming: Remove the part and trim flash manually or mechanically.
7. Post-Curing (Optional): Bake at 200–220℃ to improve heat resistance and anti-aging performance.

Example Products:

• Silicone Seals
• Silicone Keypads
• Daily Silicone Items
• Electronic Silicone Components

Advantages:

• Cost-effective for large-scale production
• Mature and stable process
• Covers a wide variety of silicone products
• High precision molding with strong dimensional stability

Limitations:

• Significant flash and waste, requires trimming
• Visible parting lines may appear
• Thicker parts may suffer from surface defects, lack of fill, or bubbles

2. Liquid Silicone Rubber (LSR) Molding

Production Steps:

1. Material Mixing: Two-component LSR (A/B, 1:1) automatically mixed by dosing system.
2. Mold Preparation: Use cold runner mold (30–50℃) to prevent premature curing.
3. Injection: Inject LSR into the mold cavity under high pressure.
4. Vulcanization: Mold rapidly heated to 180–220℃, curing in 10–30 seconds.
5. Demolding: Automatic demolding, minimal or no flash.
6. Inspection & Packaging: No post-curing required, products can be packaged directly.

Example Products:

• Baby Nipples
• Medical Catheters
• Food-Grade Accessories
• High Precision Seals

Advantages:

• High precision, suitable for complex structures
• Automated production, no trimming required
• Excellent biocompatibility, ideal for medical and baby products

Limitations:

• High equipment and tooling cost
• Less economical for very small batches
• Requires specialized LSR injection equipment

3. Silicone Extrusion Process

Production Steps:

1. Material Preparation: Solid silicone mixed with curing system, or liquid silicone directly used.
2. Extrusion: Feed material into extruder, screw extrusion through die.
3. Continuous Vulcanization: Hot air or microwave vulcanization at 120–180℃.
4. Cooling & Cutting: Cool and cut to specified lengths.
5. Inspection: Check cross-section, roundness, and surface quality.

Example Products:

• Silicone Tubes
• Weather Strips
• Sealing Profiles
• Extruded Gaskets

Advantages:

• Highly efficient for continuous production
• Cost advantage for long strips and tubes
• Simple tooling, quick setup

Limitations:

• Limited to constant cross-section products
• Not suitable for complex 3D structures
• Requires cutting after extrusion

4. Silicone Calendering Process

Production Steps:

1. Material Mixing: Solid silicone mixed with additives, pre-pressed into sheets.
2. Calendering: Pass through heated rollers at 100–150℃ with set gap.
3. Thickness Adjustment: Control roller gap to obtain 0.05–0.5 mm thickness.
4. Continuous Vulcanization: Curing at 150–180℃.
5. Cooling & Rewinding: Cool and rewind into rolls.
6. Cutting: Cut into sheets or specified sizes.

Example Products:

• Silicone Films
• Keyboard Protectors
• Waterproof Pads
• Insulation Sheets

Advantages:

• Produces ultra-thin films with uniform thickness
• High efficiency for flat sheet products
• Stable film thickness control

Limitations:

• Only suitable for flat sheet products
• Not applicable for 3D parts
• Requires post-cutting

5. Silicone Casting / Potting

Production Steps:

1. Mold Preparation: Build simple molds with resin, gypsum, or metal and apply release agent.
2. Mixing & Defoaming: Blend RTV (room-temperature-vulcanized) silicone with curing agent in the specified ratio and degas.
3. Pouring: Slowly pour the silicone into the cavity; use vibration/vacuum to remove bubbles.
4. Curing: Cure at room temperature or accelerate in an 80–120℃ oven.
5. Demolding & Finishing: Remove cured parts and trim minor overflow/flash.
6. Post-Processing: As needed—grinding, polishing, or surface coating.

Example Products:

• Large Silicone Seals
• Custom Silicone Molds
• Silicone Prototypes / Mockups
• Low-Volume Industrial Components

Advantages:

• Very low mold cost
• Highly flexible for large or customized parts
• Ideal for prototyping and validation

Limitations:

• Longer curing cycle
• Not suitable for mass production
• Mold accuracy lower than injection molding

Conclusion

Each silicone molding process has distinct strengths: HCR is cost-effective for general mass production; LSR is optimal for high-precision and medical-grade parts; extrusion fits tubes and profiles; calendering excels at ultra-thin films; and casting is great for custom or large components. The best choice depends on your design, cost target, and production volume.

At YueHouDZ, we offer custom silicone manufacturing with free 3D product modeling (tooling-ready), a low MOQ of 500 pcs, and strict NDA confidentiality. We help turn ideas into market-ready products through a one-stop workflow—from design and tooling to production and packaging.