What is tempering?
Tempering refers to the targeted heating of plastic, rubber or metal components to a defined temperature below the melting point over a certain period of time in order to reduce internal stresses, stabilise material properties or expel residual monomers and volatile components. In elastomer processing, tempering is a key step for some materials after the moulding process. Vulcanisation, especially with silicone rubber (VMQ), fluorosilicone (FVMQ) and for applications with LABS freedom (paint wetting impairment substances).
Why is tempering used?
Annealing specifically improves the dimensional stability, long-term use properties and material purity of certain rubber and plastic parts. Particularly with high-temperature cross-linked elastomers often leave reaction residues or volatile substances (e.g. peroxides, siloxanes) after processing, which are removed or neutralised by controlled heating.
Typical effects due to tempering:
- Reduction of emissions in the final state (e.g. odour, outgassing)
- Increased thermal resistance and tear resistance
- Stabilisation of dimensional accuracy
- Improvement of the surface and adhesion in subsequent processes
- Manufacture LABS-free Components (e.g. for painting lines)
Tempering usually takes place in special tempering ovens or Autoclaves, typically at temperatures between 150°C and 250°C - depending on the material.
Especially for Silicone products for electrical or medical technology, tempering is a quality standard to avoid migration and paint wetting problems.
Applications of tempering
Typical areas of application: