How to solve the burn of plastic molded parts?
Plastic product burns often occur in the processing of injection molding. According to the reasons for product burns, we can divide them into three categories, they are mechanical factor, mold structure factor, and injection molding factory. For these different reasons, we have adopted several solutions.
1. Mechanical factor. Because of the abnormal conditions, the barrel is overheated, and the overheated material will decompose in a high-temperature environment and then being injected into the products. Or the slow resin injecting caused by the check valve and screw bar in the barrel. In these cases, it is necessary to clean the nozzle, screw, and barrel.
2. Mold structure. This factor caused by the poor exhaust system in the mold structure and this kind of burn phenomenon generally occurs in a fixed place, which is easy to distinguish from the first factor. In this case, we should reconstruct the exhaust system in the mold.
3. Injection molding. When the pressure is above 300Mpa, the barrel will locally overheat and cause burns. When the screw rotation speed is too high, the temperature will also increase, and we should control the rotation speed within the range of 40~90r/min. When there is no exhaust groove in the mold or the groove size is too small, it is easy to cause burns on the product because of the overheated gas.
