Matters needing attention in compression molding
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1. During the molding of silicone products, the silicone rubber is pressed under high pressure, which cannot be eliminated due to the cohesion of the elastomer. When the silicone rubber is molded and released from the mold, it often produces extremely unstable shrinkage (the shrinkage rate of silicone rubber depends on the rubber type) And there are differences), it takes time to relax and stabilize. Therefore, at the beginning of the design of silicone products, regardless of formula or mold, careful calculation and comprehensive consideration are needed, otherwise the size of silicone products is prone to instability and the quality of the products is degraded.
2. Silicone is a hot-melt, thermosetting elastomer, and plastic is a hot-melt, cold-set. Due to the different types of silicone vulcanizing agents, the curing temperature range of silicone rubber is quite different. Even silicone rubber vulcanization can be affected by climate change and indoor temperature and humidity. Therefore, the production conditions of silicone products need to be appropriately adjusted at any time, otherwise, differences in product quality may occur.
3. Silicone products are made from silicone raw materials after mixing with a mixer, and used as raw materials. The formula is designed according to the characteristics of the required silicone rubber products during rubber mixing, and the required product hardness is determined. And the type of silicone rubber curing agent required. Silicone rubber products are molded by a rubber flat vulcanizing machine. After molding, the product is finally flashed to make the surface of the product smooth and without burrs.
4. Silicone rubber molding vulcanization process will have problems such as mold sticking, warping, bubbles, incomplete vulcanization and white spots, etc. It is necessary to adjust the mold temperature, exhaust time, and mold pressure.