Introduction: Mold is the basis of packaging material manufacturing, and it occupies a large proportion of the production cost of injection molding. Its service life directly affects the cost of injection molded products. This shows the importance of mold products to packaging materials. This article shares the five major steps of the mold production process, the content is for the reference of purchasing friends:
Plastic molds are tools that are matched with plastic molding machines in the plastic processing industry to give plastic products a complete configuration and precise dimensions. According to the different molding methods, it can be divided into different types of molds. Through the coordinated use of various systems or auxiliary mechanisms in the mold, plastic particles are liquefied at high temperature and filled into the mold cavity to produce tools for industrial parts with specific shapes, sizes, functions and quality.
Mold manufacturing is a complex process, from design, processing, assembly, debugging and other steps to the final actual use. In the entire life cycle, injection mold manufacturing can be roughly divided into the following steps:
Process analysis of plastic products
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.
Mold structure design
A set of high-quality molds requires not only good processing equipment and skilled mold manufacturing workers, but also a very important factor is to have a good mold design. Especially for complex molds, the quality of the mold design accounts for 80% of the mold quality. %the 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 do this, it is necessary not only to fully digest the customer’s requirements, but also to 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.
8) Study some special mold structures and learn about the latest mold technology.
Determine mold material and select standard parts
In the selection of mold materials, in addition to considering the accuracy and quality of the product, it is also necessary to combine the actual processing and heat treatment capabilities of the mold factory to give the correct choice. In addition, in order to shorten the manufacturing cycle, use existing standard parts as much as possible.
Parts processing and mold assembly
Except for the best structure and reasonable tolerance matching in the design, the accuracy of the mold is very important for parts processing and mold assembly. Therefore, the choice of processing accuracy and processing 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 1/3
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
Total error = (1) + (2) + (3) + (4)
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, the cavity, core and other key parts should be quenched in molds with high machining accuracy 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 adopted as much as possible in the mold design.
In order to solve the errors caused by 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 during mold manufacturing as the manufacturing tolerance of the mold, and the purpose is to leave a relatively large Large adjustment room to solve the errors caused by the molding process.
A set of molds only completes 70% to 80% of the entire manufacturing process from design to assembly. The error 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, must be tested by mold trial. Therefore, mold trial is an indispensable step to check whether the mold is qualified and select the best molding process.