Injection molding method is a production method in which the material is fed into the mold within the parameters such as quantity, time, speed, pressure determined according to the process with the help of hydraulic piston and screw-barrel group from the material chamber of the press. The material fed from the injection press to the mold passes through the mold runners, fills the mold chambers where it will take its shape, and vulcanization takes place. It is an ideal production method suitable for automation along with technological developments. In principle, thermoplastic, in which the injection production method is used frequently, is similar to metal injections, but it has some details and different aspects as in other molding methods. Piston, screw-sleeve group is always cooled to prevent unwanted pre-curing of the material. It is a superior method compared to other compression and transfer molding used in shaping silicone materials. If automation is applied efficiently, no operator is needed. Its stability and continuity are better than other methods. Mold opening and closing movements can be made automatically by the press. It provides the opportunity to produce with efficient cycles that repeat themselves. With injection molding, the process and production can be kept under control in more detail. Silicone injection presses are either horizontal or vertical. According to the manufacturer’s preference, it is possible to shape both types of silicone rubber in molds by injection.
Some advantages and disadvantages of injection molding production can be listed as follows:
• It provides a production opportunity based on completely automation. Productions with less labor and cycle times can be realized.
• More stable and continuous results can be obtained in each cycle. It is ideal for productions with high quantities and sensitive quality criteria.
• Perform productions where secondary cleaning operations are needed less and part burrs are less than compression and transfer methods.
• As in compression and transfer molding, there is no preliminary material preparation according to part geometry and weight. Therefore, the elements that require labor are eliminated.
• Although the injection molding method is efficient in most aspects, it is costly in terms of initial investments such as mold, machinery, equipment, cold runner block.