silicone extrusion molding

I. What is silicone extrusion molding?
Silicone extrusion is a continuous production process where the mixed and melted silicone raw materials are processed by the screw of the extruder, undergo pressure, and then are extruded through a specific mold to form the desired cross-sectional shape. After cooling and vulcanization, it becomes the final product.
Core advantages:
It can produce ultra-long products (with no length limit), suitable for linear products such as pipes and sealing strips;
The production efficiency is high, and it supports automated continuous operation;
By changing the mold profile, different cross-sectional shapes (circular, square, irregular, etc.) of silicone profiles can be flexibly produced.
II. Core Process of Extrusion Technology
Raw material preparation: Mix the silicone raw rubber, vulcanizing agent, color mother, etc. in proportion, and process them into uniform rubber materials through a grinding machine or a plasticizing machine (the amount of vulcanizing agent needs to be strictly controlled, slightly higher than that of molded products to ensure the stability of extrusion).
Equipment preheating: Start the extruder heating system 0.5 to 1 hour in advance, and adjust the temperatures of each section according to the process requirements (the barrel and die temperatures need to be precisely controlled to avoid premature vulcanization or uneven plasticization of the rubber).
Extrusion molding: Add the plasticized rubber to the feeding port, start the main machine, and the screw rotates to push the rubber towards the die head, which is then extruded through the mold profile to form the target shape. During the process, it is necessary to observe the density and uniformity of the extruded rubber in real time, and adjust the mold to ensure the dimensional accuracy.
Cooling and shaping: The extruded silicone semi-finished products are cooled by water or air cooling to quickly achieve shaping (to avoid deformation under high temperature).
Vulcanization and curing: The cooled silicone is still in an unvulcanized state, and it needs to immediately enter the vulcanization oven (under hot air or high-pressure steam vulcanization) to complete the cross-linking reaction and obtain the final elastic properties.
Post-processing: Cut the finished products, trim the burrs, clean, inspect, etc., to meet the product standards.