- Suzhou Haolilai Engineering Plastic Co., Ltd.
- Mobile: 86 0512 62697848
- Phone: 86 0512 62697848
- Address: South District, Guangfu Town Industrial Zone, Wuzhong District, Suzhou, Jiangsu, China
Factors affecting the size of graphite modified PP plastic parts
What are the factors that affect the size of graphite modified PP plastic parts?
Due to the conditions of production of plastic products, the factors affecting the accuracy of the modified plastic parts can be summarized into four types: the shortening rate of the modified plastic and its shake, the mold structure and its manufacturing accuracy, the mold wear, and the mold device.
The main component of plastic is resin, and its performance is mainly dominated by resin. The characteristics of plastics and the molding process conditions have a great influence on the shortening rate of plastics and the fluctuation of the shortening rate, such as the fluidity, crystallinity, elastic modulus, material temperature, mold temperature, injection pressure, holding pressure, Plasticizing back pressure, molding cycle, etc. Generally, the shortening rate of crystalline and semi-crystalline plastics is larger than that of non-crystalline plastics.
Plastic parts made of plastic with a small shortening rate have higher dimensional accuracy than plastic parts made of plastic with a large shortening rate. Even for the same plastic, due to differences in molding process conditions, plastic part structure, mold structure, and manufacturing accuracy, etc., the molding shortening rate will be shaken. This shake will cause the precision of the plastic part to change, which will affect the plastic part Precision.
Plastic parts are born out of the mold cavity. The mold structure and its manufacturing accuracy will directly affect the precision of the plastic parts. Therefore, it is necessary to comprehensively consider the design of the injection mold.
Not only the parting surface of the mold should be considered in order to shape and remove the plastic part. It is also necessary to consider the melt flow when the plastic part is molded in the mold, which involves many factors such as the distribution of the runner, the orientation of the gate, the method of exhaust, and the cooling of the mold. As long as these issues are fully considered and dealt with accordingly, it is possible to obtain plastic parts with high dimensional accuracy. During injection molding, the mold cavity must withstand high pressure. If the rigidity of the mold is insufficient, the mold will be deformed. Therefore, the dimensional accuracy of the plastic part is reduced. Therefore, when designing the mold, the mold structure must be fully considered so that it can withstand the molding pressure.
After the mold is put into production, it needs to work for a long time and work under high temperature and pressure for a long time. Some plastic additives, such as hard fillers, glass fiber, carbon fiber, etc. They are particularly prominent in the wear of the mold cavity. Over time, the size of the cavity will gradually increase, and the size of the plastic part will also increase, which will increase the size error.
In addition, the wear of certain moving parts, such as guide posts and guide sleeves, during long-term operations increases the gap, which causes the mold to reduce the accuracy of mold clamping and increase the size error.
The movement of the mold and the operation of fixing the mold are generally oriented and positioned using guide posts and guide sleeves. Therefore, the device must be accurate to ensure the accuracy of moving and fixed mold clamping. If the device is improper and the guide posts and guide sleeves are offset, the precision of the plastic parts will be reduced. It can be seen that the mold device must be taken seriously.