II. Mold structure design

For a set of molds, in addition to having good processing equipment and skilled mold manufacturing technology, there is also another very important factor: mold design! Especially for complex molds, the quality of mold design is the main factor determining mold quality. Under the premise that a mold design meets the requirements of customers, it can also reduce processing costs, processing difficulties and processing time.

To achieve this, not only the customer's requirements need to be fully digested, but also a full understanding of injection molding machines, mold structures, processing technologies and the processing capabilities of the mold factory itself is required. Therefore, to improve the level of mold design, the following points need to be done:

1. Figure out every detail in each mold design and understand the purpose of all parts in the mold.
2. Refer to similar previous designs more when designing, and understand its situation during mold processing and product production, and draw experience and lessons from it.
3. Observe the working process of the injection molding machine more to deepen the understanding of molds and injection molding machines.
4. You can go to the factory to understand the processing technology of processed products and understand the characteristics and limitations of each processing.
5. Understand the trial mold results and mold modification situation of the molds you designed and draw lessons.
6. Try to use the previously more successful mold structure in design as much as possible.
7. Learn more about the impact of mold water inlet on products.
8. Study some special mold structures and learn new mold technologies.

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 inconsistent predetermined shrinkage and actual shrinkage is about 1/6.
   Total error = (1) + (2) + (3) + (4)
   Therefore, to reduce the error of mold manufacturing, first of all, the processing accuracy should be improved. 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, for molds with higher processing accuracy requirements and larger production volumes, key parts such as cavities and cores can be quenched. In medium and large molds, in order to save materials and facilitate processing, a mosaic structure can be adopted in mold design.
   In order to solve the errors caused by uneven shrinkage of molded parts and inconsistent predetermined shrinkage and actual shrinkage, generally 1/3 of the product tolerance is selected as the manufacturing tolerance of the mold during mold manufacturing. The purpose is to leave more room for adjustment for the later molding process and facilitate solving the errors caused by the molding process in the later stage.