What is extrusion?
The extrusion of rubber is a continuous manufacturing process in which unformed rubber raw material is pressed through a moulding opening, the so-called die, to produce profiles, hoses, tubes, pipes and other products, Seals or sheathing with a constant cross-section. The extruded products are subsequently Vulcanisation fixed.
The rubber extrusion process
Firstly, a rubber compound is transported in an extruder under pressure and temperature through a screw conveyor. At the end of the extruder is the die, i.e. the moulding opening (e.g. for hollow or solid profiles). The material pressed through the die is still relatively soft and must be moulded by a subsequent Vulcanisation cured in order to maintain the shape and properties permanently.
The process is particularly suitable for the production of endless rubber moulds with constant solid and hollow cross-sections - with or without additional inserts.
Typical applications of rubber extrusion
The extrusion of rubber is used for the production of:
- Window and door seals
- Hoses and rubber sheaths
- Protective profiles for motor vehicles, machines and devices
- Sealing lips, edge protection and insulating profiles
- Multi-component profiles (co-extrusion)
The process offers high production speed and can be easily automated. However, the dimensional accuracy of the end product does not reach the level of mould-based production processes. The selection of suitable rubber types (e.g. EPDM, NBR, CR or Silicone) depends on the application, media and temperature resistance.