Injection mold manufacturing can be roughly divided into the following steps:
Before the mold design, the designer should fully analyze and study whether the plastic product conforms to the injection molding processing principle, and needs to negotiate with the product designer carefully, and a consensus has been reached. Including the geometric shape, dimensional accuracy, and appearance requirements of the product, necessary discussions, try to avoid unnecessary complexity in mold manufacturing.
A set of high-quality molds requires not only good processing equipment and skilled mold manufacturing workers but also a very important factor is a good mold design. Especially for complex molds, the quality of the mold design accounts for 80% of the mold quality. %above. An excellent mold design is: on the premise of meeting the requirements of the customers, the processing cost is low, the processing difficulty is small, and the processing time is short.
To achieve this, we must not only fully digest the customer's requirements, but also have an understanding of the injection molding machine, mold structure, processing technology, and the mold factory's own processing capabilities. Therefore, to improve the level of mold design, the following points should be achieved:
1. Understand every detail in the design of each mold, and understand the purpose of each part in the mold.
2. When designing, refer to previous similar designs, 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. Under the factory, understand the process of processed products and recognize the characteristics and limitations of each process.
5. Understand the results of mold trial and mold modification of the mold designed by yourself, and learn lessons.
6. When designing, try to use the more successful mold structure before.
7. Know more about the impact of mold water on products.
Study some special mold structures and learn about the latest mold technology.
In the selection of mold materials, in addition to considering the accuracy and quality of the product, the correct choice must be made in combination with the actual processing and heat treatment capabilities of the mold factory. In addition, in order to shorten the manufacturing cycle, use existing standard parts as much as possible.
Except for the best structure and reasonable tolerance fit in the design, the accuracy of the mold is very important for parts processing and mould assembly. Therefore, the choice of processing accuracy and processing method occupies an absolutely 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 1/3
2. The error caused by mold wear is about 1/6
3. The error caused by uneven shrinkage of molded parts is about 1/3
4. The error caused by the inconsistency between the scheduled contraction and the actual contraction is about 1/6
Therefore, in order to reduce mold manufacturing errors, 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, the cavity, core, and other key parts should be quenched in molds with high processing accuracy and large product output. In the medium and large molds, in order to save materials and facilitate processing and heat treatment, the mosaic structure should be adopted as much as possible in the mold design.
In order to solve the error caused by uneven shrinkage of the molded part and the inconsistency between the predetermined shrinkage and the actual shrinkage, 1/3 of the product tolerance is generally selected during mold manufacturing, as the manufacturing tolerance of the mold, and the purpose is to leave a relatively large margin for the subsequent molding process. Large room for adjustment to solve the errors caused by the molding process.
A set of molds only completes 70% to 80% of the entire manufacturing process from the beginning of the design to the completion of assembly. For the errors caused by the inconsistency between the predetermined shrinkage and the actual shrinkage, whether the demolding is smooth or not, how the cooling effect is, 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 mold trial. Therefore, a mold trial is an indispensable step to check whether the mold is qualified and select the best molding process.