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Injection mold manufacturing can be roughly divided into the following steps:First, Process analysis of plastic productsBefore the mold design, the designer should fully analyze and study whether the plastic product conforms to the principle of injection molding, and needs to negotiate carefully with the product designer, and a consensus has been reached. This includes necessary discussions on the geometric shape, dimensional accuracy, appearance requirements of the product, and try to avoid unnecessary complexity in mold manufacturing.
Second, the mold structure designA set of high-quality molds not only requires good processing equipment and skilled mold manufacturing workers, but also a very important factor is to have good mold design, especially for complex molds, the quality of mold design accounts for more than 80 percent. An excellent mold design is: on the premise of meeting the requirements of customers, the processing cost is low, the processing difficulty is small, and the processing time is short.
To do this, it is necessary not only to fully digest the requirements of the guests, but also to have an understanding of the injection molding machine, mold structure, processing technology and the processing capacity of the mold factory itself. Therefore, to improve the level of mold design, the following points should be done:
1. Understand every detail in each mold design, and understand the purpose of each part in the mold.
2. Refer to the previous similar designs when designing, and understand the situation in its mold processing and product production, and learn from the experience and lessons.
3. Learn more about the working process of the injection molding machine to deepen the relationship between the mold and the injection molding machine.
4. Go to the factory to understand the process of processed products, and recognize the characteristics and limitations of each type of processing.
5. Understand the test results and mold modification of the mold and learn from it.
6. Try to use the more successful mold structure in the design.
7. Learn more about the influence of water in the mold on the product.
8. Study some special mold structures and understand new mold technology.
Third, determine the mold material and select standard partsIn the selection of mold materials, in addition to considering the accuracy and quality of the product, it is also necessary to give the correct choice in combination with the actual ability of the mold factory's processing and heat treatment. In addition, in order to shorten the manufacturing cycle, the existing standard parts are used as much as possible.
Fourth, parts processing and mold assemblyIn addition to giving better structure and reasonable tolerance in the design of mold precision, parts processing and mold assembly are very important. Therefore, the choice of machining accuracy and machining method occupies an absolute dominant position in mold manufacturing.
The dimensional error of molded products is mainly composed of the following parts:1. The manufacturing error of the mold is about 1/32. The error caused by mold wear is about 1/63. The error caused by uneven shrinkage of the molded part is about 1/34. The error caused by the inconsistency between the scheduled shrinkage and the actual shrinkage is about 1/6
Therefore, in order to reduce the mold manufacturing error, the machining accuracy should be improved first. With the use of CNC machine tools, this problem has been well controlled. In addition, in order to prevent errors caused by mold wear and deformation, quenching should be used for key parts such as cavities and cores in molds with high machining accuracy requirements and large product output. In medium and large molds, in order to save materials and facilitate processing and heat treatment, the mosaic structure should be used as much as possible in mold design.
In order to solve the error caused by the uneven shrinkage of the molded parts and the inconsistency between the predetermined shrinkage and the actual shrinkage, 1/3 of the product tolerance is generally selected in the mold manufacturing as the manufacturing tolerance of the mold. Large room for adjustment to account for errors caused by the molding process.
Fifth, the trial testA set of molds is only 70% to 80% of the entire manufacturing process from the beginning of design to the completion of assembly. For the error caused by the inconsistency between the predetermined shrinkage and the actual shrinkage, whether the demoulding is successful or not, how is the cooling effect, especially the influence of the size, position and shape of the gate on the accuracy and appearance of the product, it must be tested by the mold test. Therefore, mold trial is an indispensable step to check whether the mold is qualified or not and to select the molding process.