Choosing the Right Silicone Rubber Extrusions: Key Factors & Customization

Selecting the correct silicone rubber extrusions is paramount to ensuring the performance, longevity, and safety of your final product or system. With various grades, hardness levels, and the option for full customization, making an informed choice requires careful consideration of the application’s specific demands. This guide walks you through the key factors to evaluate when specifying or purchasing silicone rubber extrusions.

Define Your Application Requirements

Before diving into material specifics, clearly outline the operational environment:

• Temperature Range: What are the minimum and maximum continuous and intermittent operating temperatures? This dictates whether standard, high-temp, or low-temp silicone is needed.
• Chemical Exposure: What fluids, solvents, or chemicals will the extrusion encounter? Specify these to ensure appropriate chemical resistance.
• Pressure/Vacuum: Will the extrusion be subjected to significant pressure or vacuum? This influences wall thickness and material strength requirements, especially for silicone tubing.
• Environmental Factors: Will there be exposure to UV, ozone, weathering, or abrasion?
• Mechanical Stress: Will it undergo compression, tension, or flexing? Consider compression set requirements.

Select the Appropriate Silicone Grade

Different formulations cater to specific needs:

• General Purpose: Suitable for many standard industrial applications with moderate temperature requirements.
• High-Temperature Grade: Formulated to withstand temperatures exceeding 200°C, sometimes up to 300°C.
• Low-Temperature Grade: Retains flexibility at extremely low temperatures (below -60°C).
• Food-Grade: Meets regulatory standards like FDA 21 CFR 177.2600 for safe contact with food and beverages. Look for FDA-approved silicone extrusions.
• Medical-Grade: Biocompatible materials meeting USP Class VI or ISO 10993 for healthcare applications. Often requires platinum curing.
• Flame Retardant: Meets specific flammability ratings (e.g., UL 94 V-0) for electronics or transportation.
• Electrically Conductive/Static Dissipative: For applications requiring grounding or shielding.

Determine Hardness (Durometer)

Silicone hardness, measured on the Shore A scale, affects flexibility and compressibility:

• Lower Durometer (20A-40A): Softer, more flexible, better for low-pressure seals needing conformity.
• Medium Durometer (50A-70A): Most common range, offering a good balance of flexibility and firmness for general sealing and tubing.
• Higher Durometer (80A+): Firmer, less flexible, better for high-pressure seals or when rigidity is needed.

Consider Profile Design and Tolerances

Standard vs. Custom Profiles: Can a standard shape (tube, cord, square) meet your needs, or do you require a custom silicone profile? Custom dies allow for intricate geometries tailored to your exact specifications. Tolerances: How precise do the dimensions need to be? Tighter tolerances often increase cost but may be critical for proper sealing or fit. Discuss achievable tolerances with your silicone extrusion manufacturer.

Color and Appearance

While standard silicone rubber extrusions are often translucent or white, they can be pigmented to virtually any color for coding, branding, or aesthetic purposes.

Certifications and Compliance

Ensure the chosen material and manufacturer can provide necessary certifications (FDA, USP Class VI, NSF, UL, WRAS, etc.) relevant to your industry and application.

The Power of Customization

Working with an experienced silicone extrusion manufacturer opens the door to custom silicone rubber extrusions. This involves:

• Design Collaboration: Refining your profile design for optimal performance and manufacturability.
• Custom Tooling (Dies): Creating the specific die for your unique shape.
• Material Formulation: Adjusting the silicone compound for specific properties.
• Secondary Operations: Cutting to length, splicing into O-rings, applying pressure-sensitive adhesive (PSA), printing/marking.

Selecting the right silicone rubber extrusion requires matching material properties and form factor design to the specific needs of your application. By carefully considering temperature, chemical exposure, hardness, and required certifications, and leveraging the potential of custom silicone extrusions, you can ensure optimal performance and reliability.

Ready to find the perfect silicone rubber extrusion solution? Work with our experts. Contact us for a consultation or quote on your silicone raw material standard or custom requirements!