Injection molding process of liquid silica gel
The liquid silica gel is divided into A components and B components. The mixing machine combines the A component and the B component with the exact 1:1 ratio. Because part of the products are designed for color, the mixer is equipped with a color pump unit and a color measurement section. A+B component, additive, color and so on are fully mixed into the plasticizing system.
Key technological requirements for injection molding of liquid silica gel
The rheological behavior of liquid silica is mainly characterized by low viscosity, rapid solidification, shear thinning and higher coefficient of thermal expansion. Therefore, it is necessary to control the process of its forming process. Especially in the feeding and injection molding.
Feed - one - way pump system
The synchronous single pump with a check valve also needs to be matched with the corresponding metering tube system to effectively control the precision of the feed.
Injection mold design
Because the expansion coefficient of liquid silica is high, it will expand when heated, and there will be slight shrinkage when cooling. Therefore, parts can not keep the precise side distance in the mold, so the cold runner mold design should be adopted.
In order to avoid turbulence and use of injection needle or small plastic mouth. The T type guide suppository is used instead of the cylindrical guide bolt to increase the positioning accuracy. The heat insulation layer / plate is set up to facilitate the curing of liquid silica gel.
Injection molding parts
Due to the low viscosity of liquid silica gel, the reflux and leakage of material should be considered in the process of processing, so the sealing of the injection screw is very important. When the glue is finished, the nozzle will be closed immediately, and a needle valve must be used to shoot the mouth.
Market prospect of liquid silica gel injection molding technology
The liquid silicone injection molding technology is a new type of high efficiency silicon rubber molding method developed at the end of 70s, after years of research and development, the market has been more and more widely used in the production of silicone rubber products, thus ushered in a new era of silicon rubber industry with high efficiency, high quality and low cost of production.
Compared with the traditional hot vulcanization process, the technology process of rubber products has the advantages of saving time and energy, eliminating post-processing technology, high yield and low comprehensive cost (saving around 40%). It is foreseeable that the injection molding technology of liquid silica gel material will have a good market prospect.