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To make a perfect injection mold, following these five steps is essential

2021-09-25

To make a perfect injection mold, following these five steps is essential

One, 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, and the designer of the product needs to negotiate carefully, and a consensus has been reached. Including the product geometry, dimensional accuracy and appearance requirements, necessary discussion, as far as possible to avoid unnecessary complex mold manufacturing.

Second, 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 good mold design, especially for complex mold, mold design quality accounts for more than 80% of the mold quality. An excellent mold design is: on the premise of meeting the requirements of customers, 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 customer's requirements, but also to understand 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 purpose of each part in the mold.

2. Refer to previous similar designs in the design, and understand the situation of mold processing and product production, and 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. Go to the factory to understand the process of processed products, and understand the characteristics and limitations of each process.

5. Understand the mold test results and mold modification of the mold designed by myself, and learn lessons.

6. Try to use the previous successful mold structure in the design.

7. Learn more about the impact of mold water on products.

8. Study some special die structure and understand the latest die technology.

Three, determine the mold material and select standard parts.

In the selection of mold materials, in addition to considering the accuracy and quality of products, but also combined with the actual capacity of mold factory processing and heat treatment to give the correct choice. In addition, in order to shorten the manufacturing cycle, use existing standard parts as much as possible.

 

Four, parts processing and mold assembly.

In addition to the precision of the mold in the design of the best structure and reasonable tolerance fit, parts processing and mold assembly is crucial. Therefore, the choice of machining precision and machining method plays an absolute leading role in mold 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 the molding parts is about 1/3

4. The error caused by the inconsistency between the scheduled contraction and the actual contraction is about 1/6

Total error = (1) + (2) + (3) + (4)

Therefore, in order to reduce the mold manufacturing error, we should first improve the machining accuracy, with the use of CNC machine tools, this problem has been well controlled. In addition, in order to prevent the error caused by mold wear and deformation, in the processing of higher precision requirements and larger product output of the mold, the cavity, core and other key parts should be treated by quenching. In the medium and large mold, in order to save material 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 and the scheduled shrinkage and the actual shrinkage, the general selection of product tolerance in mold manufacturing 1/3, as the mold manufacturing tolerance, its purpose is to give the later molding process to leave a large adjustment room, in order to solve the molding process caused by the error.

Five, mold test.

A set of molds from the design to the completion of assembly, only 70 to 80 percent of its total manufacturing process. For the error caused by the inconsistency between the scheduled shrinkage and the actual shrinkage, whether the demoulding is smooth or not, how the cooling effect is, especially the size, position and shape of the gate on the accuracy and appearance of the products and other problems, we must test the mold. Therefore, mold testing is an indispensable step to check whether the mold is qualified and select the best forming process.