The five steps of the injection mold production process
First, the process analysis of plastic products.
Before the mold design, the designer should fully analyze and study whether the plastic products conform to the principle of injection molding processing, need to carefully negotiate with the designer of the product, has reached a consensus. Including the geometric shape of the product, dimensional accuracy and appearance requirements, necessary discussion, as far as possible to avoid unnecessary complexity in mold manufacturing.
Two, mold structure design.
A set of high-quality mold, not only need to have good processing equipment and skilled mold manufacturing workers, another very important factor is to have a good mold design, especially for complex mold, mold design quality accounts for more than 80% of the mold quality. An excellent mold design is: under the premise of meeting the requirements of guests, so that the processing cost is low, the processing difficulty is small, the processing time is short.
To do this, 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 mold factory's own processing capacity. Therefore, to improve the level of mold design, the following points should be done:
1. Understand every detail in the design of each mold and understand the use of each part in the mold.
2. In the design of reference to the previous similar design, and understand the situation in its mold processing and product production, learn the experience and lessons.
3. Learn more about the working process of injection molding machine to deepen the relationship between mold and injection molding machine.
4. Visit the factory to understand the process of processed products, and understand the characteristics and limitations of each process.
5. Understand the test results and mold modification of the molds designed by myself, and learn lessons.
6. Try to use the mold structure which was more successful before in the design.
7. Know more about the influence of mold entering water on products.
8. Study some special mold structures and understand the latest mold technology.
Three, determine the mold material and choose standard parts.
In the selection of die materials, in addition to considering the accuracy and quality of the product, but also combined with the actual ability of the processing and heat treatment of the die factory to give the correct choice. In addition, in order to shorten the manufacturing cycle, existing standard parts are used as much as possible.
Four, parts processing and mold assembly.
In addition to giving the best structure and reasonable tolerance in the design of the precision of the mold, parts processing and mold assembly is very important. Therefore, the selection of machining precision and machining method occupies an absolutely dominant position in die manufacturing.
The size error of molding 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 molding parts is about 1/3
4. The error caused by the inconsistency between predetermined shrinkage and actual shrinkage is about 1/6
Therefore, in order to reduce the mold manufacturing error, first of all should improve the machining accuracy, with the use of CNC machine tools, this problem has been well controlled. In addition, in order to prevent the mold wear, deformation caused by the error, in the processing accuracy requirements of higher and larger product output of the mold, the cavity, core and other key parts should be quenched. In the medium and large mold, in order to save materials and facilitate processing and heat treatment, mold design should try to use Mosaic structure.
In order to solve the error caused by the uneven shrinkage of forming 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, which is used as the manufacturing tolerance of the mold. The purpose is to leave greater room for adjustment in the later molding process, so as to solve the error caused by the molding process.
Five, test mold.
A set of mold from the beginning of design to assembly, only to complete the entire manufacturing process of 70%~80%. For the error caused by the inconsistency between the predetermined shrinkage and the actual shrinkage, whether the demoulding 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 the mold test. Therefore, mold testing is an indispensable step to check whether the mold is qualified and choose the best forming process.