The typical temperature ranges for convection oven post-curing of silicone rubber (especially Liquid Silicone Rubber, or LSR) are as follows:
Standard Temperature Ranges
200°C to 250°C (392°F to 482°F)
The most commonly used range for post-curing LSR products.
Effective for removing volatiles, completing crosslinking, and enhancing mechanical properties.
Lower Range: 150°C to 200°C (302°F to 392°F)
Used when:
The silicone has a slower cure formulation.
The parts are thin-walled and heat-sensitive.
Gradual heating is required to avoid thermal stress.
Results in longer curing times but reduces the risk of overheating.
Higher Range: 250°C to 300°C (482°F to 572°F)
Applied for rapid post-curing or materials requiring higher thermal stabilization.
Often used for industrial or automotive-grade silicones.
Requires careful monitoring to prevent over-curing or degradation.
Considerations for Choosing Temperature
Material Type:
Refer to the manufacturer's technical datasheet for the specific temperature recommendations of the LSR grade.
Some medical or food-grade silicones require controlled lower temperatures to meet regulatory standards.
Part Thickness:
Thin Parts: Lower temperatures for a longer duration to prevent warping.
Thick Parts: Higher temperatures can be used to ensure complete heat penetration.
Volatile Removal:
Higher temperatures accelerate the removal of residual byproducts, but excessive heating can degrade the silicone surface.
Regulatory Compliance:
Some standards (e.g., FDA or USP Class VI) may specify temperature limits to avoid contaminant formation.
Examples of Applications
| Application | Typical Temperature Range |
|---|---|
| Medical-Grade Silicone | 200°C to 230°C (392°F to 446°F) |
| Automotive Components | 230°C to 250°C (446°F to 482°F) |
| High-Purity Electronics | 200°C to 250°C (392°F to 482°F) |
| Industrial Gaskets & Seals | 250°C to 300°C (482°F to 572°F) |
Key Notes
Ramp-Up Approach: Gradually increasing the oven temperature reduces thermal shock, especially for thick or large parts.
Duration: Higher temperatures reduce curing time (e.g., 2–4 hours at 200–250°C), while lower temperatures require longer durations.
Ventilation: Ensure proper airflow in the oven to remove volatiles effectively during curing.
By selecting the appropriate temperature within these ranges, you can optimize the silicone's mechanical, thermal, and chemical properties while ensuring product quality.