Silicone is one of the most stable and versatile elastomers available. It withstands extreme temperatures, maintains elasticity for years and resists chemical environments that rapidly degrade other materials. Behind a technical gasket, a tube or an extruded profile, however, lies a far more complex engineering process than it appears.
Manufacturing silicone is not simply mixing a rubber and shaping it. It requires controlling an entire chain of variables: formulation, mixing, calendering, extrusion or molding, vulcanization, cooling, cutting, splicing and final validation. A minimal deviation in any step changes hardness, tolerances, thermal ageing or even service life.
When the plant operates under ISO 9001 and ISO 13485 certification, that level of control impacts the whole factory, not only the medical sector. Quality stops being a requirement and becomes a structural obligation.
1. Compound formulation: where everything starts
Silicone does not arrive ready for extrusion. A tailored compound must be formulated based on the application and the manufacturing process. There are two main industrial families: solid silicone HCR/HTV and liquid silicone LSR.
- Solid silicone HCR / HTV: high-consistency rubber for extrusion, compression or transfer molding.
- Liquid silicone rubber LSR: a low-viscosity two-component system, ideal for complex geometries and medical or precision applications.
The silicon–oxygen backbone provides chemical inertia, thermal stability and elasticity at elevated temperatures. However, an industrial compound is not only polymer: it includes fumed silica, catalysts, pigments, curing systems (peroxide or platinum), thermal additives, functional fillers and behavior modifiers.
2. Mixing and calendering: achieving homogeneity before shaping
In HCR compounds, the material passes through a calendering process using rollers. It is one of the most critical steps, even though it is rarely explained publicly. This stage ensures proper silica dispersion, the right plasticity and removal of microbubbles.
- Plasticity control
- Mixing temperature control
- Elimination of trapped air
- Homogeneous dispersion of fillers
- Preparation for extrusion or molding
3. Extrusion: shaping with millimetric precision
Extrusion feeds material into an extruder, compresses it with a screw, pushes it through a die and cures it in a heating tunnel. Cooling and cutting then stabilize the final geometry.
- Die swell: expansion when leaving the die (5–20%).
- Shrinkage: contraction during curing.
- Warping: torsion caused by uneven mixing or thermal imbalance.
- ISO 3302-1 tolerances: influenced by pressure, die geometry, line speed and curing time.
4. Molding: geometries impossible to extrude
When the part cannot be produced as a continuous profile, molding is used: LSR injection, compression or transfer molding. LSR injection offers the highest dimensional precision and repeatability, especially in medical, electronic and high-precision sectors.
- Automated A+B mixing
- Injection into closed molds
- Platinum curing without by-products
- Controlled cooling and demolding
5. Vulcanization: when silicone becomes silicone
Uncured silicone is not a functional elastomer. Vulcanization transforms the material into a stable crosslinked network. Two main systems exist: peroxide curing and platinum curing.
- Peroxide curing: typically 140–180°C, may require post-curing.
- Platinum curing: clean, stable and without by-products; preferred for LSR and critical applications.
Small variations in time, temperature or wall thickness can alter hardness by 5–8 Shore A points, affecting sealing performance and elastic recovery.
6. Cutting, splicing and finishing: turning a profile into a functional gasket
A gasket is rarely used in the exact form in which it exits the extrusion line. It must be cut, spliced and vulcanized into a closed frame or perimeter seal. Each operation requires strict dimensional tolerance and visual inspection.
- Cutting to size
- Hot splicing
- Mold-vulcanized joints
- Food-grade or technical adhesives
- Specialized lubrication
- Visual and dimensional inspection
7. The quality system: where the factory determines the outcome
This is where the difference between a true manufacturer and a distributor becomes evident. A plant certified under ISO 9001 and ISO 13485 controls every stage of the process with full traceability, calibration records, environmental control and documented validation.
- ISO 9001 – industrial quality management
- ISO 13485 – medical-grade process control
- ISO 8 cleanroom – particle and microbiological control
- EN 45545-2 – fire, smoke and toxicity requirements
- Testing: ISO 3302-1, ISO 48, ISO 37, ISO 815, ISO 1817
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View product →Conclusion
Industrial silicone manufacturing is a discipline where chemistry, engineering, thermal processes and high-level standards converge. Every gasket, tube or technical profile is the result of controlled decisions in formulation, mixing, extrusion, curing and validation. When the factory behind the product is certified under ISO 9001, ISO 13485 and compliant with EN 45545-2, the manufacturing standard shifts from simply industrial to truly critical.
This is what allows a silicone profile or gasket to maintain precision and sealing performance for years in medical devices, railway systems, industrial machinery or advanced sealing applications.
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