Causes and Countermeasures of Defects in Plastic Parts
Plastics are widely used in our daily life, metal and glass, and it is an indispensable substance. Plastics have many advantages, such as low cost, good insulation and excellent heat resistance. At the same time, due to the special nature of plastic materials, its processing process is more complicated than ordinary metal and glass products, and the process parameters and mold design have a very important impact on the quality of plastic parts.
The causes of defects in plastic parts mainly include the following four aspects:
1. Improper formulation
The formulation of plastic materials is the basis of plastic parts processing. As an important part of the product’s functional requirements, the formulation components and the choice of raw materials have a certain relationship and cannot be ignored. Improper formulation will cause defects such as plastic parts short shot, deformations, sink marks and voids, etc.
2. Poor manufacture
The injection molding process is simple, but it has great requirements for the technicians. The most important parameter of injection molding process is the injection speed to be strictly controlled. Too slow injection speed will cause cold air shrinkage, which will cause defects such as contraction and shrinkage marks, sink marks, etc. If the injection speed is too fast, it will easily cause flash defects, etc.
3. Poor design of plastic parts
Plastic parts are mostly designed and manufactured according to the customers drawings. If the design of the plastic parts is not reasonable, such as improper shape, lack of radial draft angle, difficult to demould, etc., it inevitable leads to the increase of internal stress, and it is easy to cause plastic parts parted and deformation during the production process, cracking and warping.
4. Poor mold maintenance
Injection molding is an efficient plastic parts production process. Mold is one of the most important processes and a prerequisite to ensure the quality of plastic parts. Improper mold maintenance working process and short of anti-rust processing will easily lead to mold jam and poor plasticizing of plastic parts, thus affecting the quality of plastic parts.
Therefore, in order to ensure the quality of plastic parts, it is necessary to optimize the formulation of plastic materials, carry out strict process design, carefully maintain the injection mold, and strictly control the quality of raw materials. The following points should be noted in the injection molding process:
1. The mold temperature and injection pressure should be properly adjusted. It is necessary to appropriately increase or decrease the mold temperature and injection pressure according to the process requirements.
2. Check the maturity of plastic parts. It is necessary to regularly check the maturity of plastic parts during production, especially when the plastic parts are used for sealing or products with special requirements.
3. Pay attention to the uniformity of raw materials. Before the plastic parts are injected, it is necessary to observe the uniformity of raw materials to determine whether the injection speed is uniform.
4. Clean the mold regularly. It is necessary to regularly clean the injection mold to remove impurities and debris, so as to prevent blockage and damage of the mold cavity.
5. Check the main parameters of the injection process in time. The injection process parameters should be optimized in a timely manner, and corresponding solutions should be taken according to the actual situation.
In short, the quality of plastic parts is affected by many factors in the injection molding process, and measures must be taken to ensure the normal operation of the production process, so as to avoid the occurrence of defects in plastic parts and ensure the smooth progress of production.
