Rubber extrusion process: how profile manufacturing works
Extrusion is a method of continuous production of rubber profiles with a long and constant cross-section — door and window seals, bellows profiles, hoses and insulation strips. In this process, the compacted rubber compound is heated, made plastic and passed through a special die (matrix) to give it the desired shape.
Main stages of the extrusion process
Profile manufacturing consists of several sequential steps, and precision at each stage determines the quality of the final product.
1. Preparation of the rubber compound
The first step is the correct formulation. The base rubber (EPDM, NBR, SBR, etc.) is mixed with fillers, plasticizers and vulcanizing agents. You can read more about this stage in our article on rubber compounds.
2. Feeding and heating
The prepared compound is fed into the extruder's feed hopper. Here a rotating screw pushes the material forward, compresses it and, through friction, heats it up to 80–120 °C. The material softens and becomes flowable, yet retains its shape.
3. Passing through the die
The heated mass is forced through the die under high pressure. The internal profile of the die determines the cross-section of the final product — in other words, the shape of the seal is born here. Manufacturing the die is the most important engineering task in extrusion.
4. Vulcanization
The shaped profile is still soft. To make it durable and elastic, it is passed through a heat channel (microwave, hot air or salt bath). As a result of vulcanization, cross-links form between the polymer chains and the rubber acquires its final mechanical properties.
Advantages of extrusion
- Continuous production: profiles of any length can be produced.
- High productivity: hundreds of meters of material are produced per hour.
- Complex cross-section: multi-chamber profiles or profiles with metal reinforcement can be made.
- Material savings: waste is minimal and the process is easy to optimize.
Which products are made by extrusion?
At NUR KAUÇUK, the extrusion line is used to produce door and window seals, automotive bellows profiles, U-profiles, square and round cords, and protective strips. Material selection depends on the application environment — EPDM is preferred for profiles working outdoors, while NBR dominates for oil-and-fuel environments. You can learn about the production stages in our manufacturing section.
Compared with compression and injection methods, extrusion is the most efficient solution for long products with a constant cross-section; for complex-shaped parts, injection molding is more suitable.
Do you have a profile and seal order? Explore our ready-made products and contact us for a made-to-measure extrusion profile.