What are the requirements for injection mold design?

1. In-depth analysis of the structure of plastic parts and its technical requirements. The structure of the plastic part determines the complexity of the injection mold structure, and the technical requirements (dimensional accuracy, surface roughness, etc.) of the plastic part determine the difficulty of the injection mold manufacturing and molding process. , unreasonable structure and shape, etc., should propose an improved design plan for injection parts, otherwise it will increase the difficulty of injection mold design and manufacturing and injection molding process.

2. Familiar with the technical specifications of the injection molding machine. The technical specifications of the injection molding machine restrict the size of the injection mold and the range of injection molded products that can be molded.

3. Understand the processing performance and process performance of plastics. Including the flow position of the plastic melt, the larger flow distance ratio that the melt can achieve: analyze the flow resistance of the runner and the cavity, the discharge of the original air in the cavity, and the possible occurrence of plastic in the injection mold. Crystallization, orientation and its resulting internal stress, plastic cooling shrinkage and compensation problems, plastic requirements for injection mold temperature, etc.

4. Consider the design and manufacture of injection molds, mainly to solve the following problems.
a. The injection mold structure should be reasonably selected. According to the drawings and technical requirements of plastic parts, research and select appropriate molding methods and equipment, and combine the mechanical processing capabilities of the factory to propose an injection mold structure plan, fully solicit opinions from relevant parties, and conduct analysis and discussion in order to design the injection mold structure. Reasonable, reliable quality, easy to operate. If necessary, according to the needs of injection mold design and processing, the requirements for modifying the drawings of plastic parts can be put forward, but it can only be implemented after obtaining the consent of the user.
b. The dimensions of injection-molded parts should be calculated correctly. Molded parts are a direct factor in determining the shape, size and surface quality of plastic parts, which are closely related and require special attention. When calculating the size of molded parts, the average shrinkage method can generally be used. For plastic parts with high precision and need to control the mold repair allowance, it can be calculated according to the tolerance zone method. For large precision plastic parts, try to use the analogy method to measure the shrinkage rate of the geometric shape of the plastic parts in different directions to calculate. Make up for the influence of some factors that are difficult to consider in theory.
c. The designed injection mold should be easy to manufacture. When designing an injection mold, try to make the designed injection mold easy to manufacture and cheap. Especially for those more complex molded parts, it must be considered whether to use general machining methods or special processing methods. If special processing methods are used, how to assemble after processing, and similar problems need to be considered and solved when designing injection molds. At the same time, mold repair after mold trial should also be considered, and sufficient mold repair allowance should be left.
d. The designed injection mold should be efficient, safe and reliable. This requirement involves many aspects of injection mold design, such as the need to charge the gating system, the closed module, the good effect of temperature adjustment, and the flexible and reliable demolding mechanism.
e, injection mold parts should be wear-resistant and durable. The durability of injection mold parts affects the service life of the entire injection mold. Therefore, when designing such parts, not only the necessary requirements should be put forward for their materials, processing methods, heat treatment, etc., but also pins such as push rods are easy to get stuck. Bending, breaking, and the resulting failures account for the majority of injection mold failures. For this reason, how to easily adjust and replace should also be considered, but it should be noted that the life of the parts is compatible with the injection mold.
f. The injection mold structure should be adapted to the molding characteristics of the plastic. When designing an injection mold, it is necessary to fully understand the molding characteristics of the plastic used and try to meet the requirements, which is also an important measure to obtain high-quality plastic parts.

swymould.com