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Plastic mold design common problems

In many industrial products, the size and shape of products are relatively high. Therefore, it is necessary to plastic mold designers using plastic reasonable mold design, in order to improve the industrial products production efficiency. But in the plastic mold designers design the corresponding mold process, there often exist some problems, such as plastic mold tolerance marking, shrinkage rate, cooling degree is not a problem, seriously affected the plastics mold design efficiency.
First, the tolerance mark. For different products, different proportion of plastic mold, tolerance mark low, precision plastic mold is not high, tolerance marking high, plastic mold processing technology is relatively complicated. Therefore, in the designer plastic mold design process, first and foremost consideration is plastic mold tolerance marking problems. But in the actual design process, there are still some design personnel in accordance with the experience of choosing tolerance marking, resulting in the size and shape of the plastic mold is error, the influence of plastic mould design quality and the reference value.
Second, the shrinkage rate is different. In the plastic mould making process under high temperature and high pressure conditions, plastic melt into a liquid, in corresponding to the mold cavity in injection. In the process of liquid plastic molding, by the impact of the characteristics of the plastic itself, the size of the plastic mold will be slightly smaller than the mold cavity. In the designer plastic mold design process, must will shrink into account, but some designers did not aware of the different types of plastic, the shrinkage rate is different, the unified standard cannot be applied for calculation of shrinkage. Once the shrinkage rate calculation errors, then the size of the plastic mold will also be affected;
Third, the coefficient of thermal expansion is different. Different plastic materials have different coefficient of thermal expansion, which directly affects the shape and size of the plastic cooling. Therefore, in the design of plastic mold, the designer must also test the coefficient of thermal expansion, and according to the actual situation, the appropriate adjustment of the design size of plastic mold. But some designers did not strictly comply with the design process, ignoring the utilization coefficient of thermal expansion, leading to there are certain differences between cooling after the plastic mold and the actual demand of plastic mold, thereby affecting the efficiency of the plastic mold design.