What are the requirements of injection mold design?

1. Deeply analyze the structure and technical requirements of plastic parts. The structure of plastic parts determines the complexity of the injection mold structure, and the technical requirements of plastic parts (dimensional accuracy, surface roughness, etc.) determine the difficulty of the injection mold manufacturing and molding process. Therefore, for the special requirements of plastic injection molding, unreasonable structure shape, etc., the improvement design scheme of injection parts should be put forward, otherwise the injection mold design will be increased Considering the difficulty of manufacturing and injection molding process.
2. Familiar with the technical specifications of injection molding machine. The technical specifications of injection molding machine restrict the size of injection mold and the range of injection products.
3. Understand the processing and processing properties of plastics. It includes the flow position of the plastic melt, the larger flow distance ratio that the melt can reach, the analysis of the flow resistance in the runner and cavity, the discharge of the original air in the mold cavity, the possible crystallization and orientation of the plastic in the injection mold, the internal stress caused by it, the cooling shrinkage and compensation of the plastic, and the requirements of the plastic on the temperature of the injection mold.
4. Consider the design and manufacture of injection mold, mainly solve the following problems.
a. The structure of injection mold should be selected reasonably. According to the drawings and technical requirements of plastic parts, research and select the appropriate molding methods and equipment, combined with the mechanical processing capacity of the factory, put forward the injection mold structure scheme, fully solicit the opinions of the relevant parties, analyze and discuss, so as to design the injection mold with reasonable structure, reliable quality and convenient operation. If necessary, according to the needs of injection mold design and processing, the requirement of modifying the drawing of plastic parts can be put forward, but it can only be implemented with the consent of the user.
b. The size of injection molding parts should be calculated correctly. Molding parts are the direct factors to determine the shape, size and surface quality of plastic parts, which are closely related and need special attention. The average shrinkage method can be used to calculate the size of parts. For the plastic parts with high precision and need to control the trimming allowance, the tolerance zone method can be used to calculate. For large precision plastic parts, the analogy method can be used as far as possible to measure the shrinkage rate of plastic parts in different directions, so as to 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 the injection mold, try to make the designed injection mold easy to manufacture and cheap. Especially for those more complex forming parts, we must consider whether to use the general machining method or the special machining method. If a special processing method is adopted, how to assemble after processing and similar problems need to be considered and solved in the design of injection mold. At the same time, the repair after mold test should also be considered, and sufficient repair allowance should be left.
d. The injection mould should be designed with high efficiency, safety and reliability. This requirement involves many aspects of injection mold design, such as the gating system needs to be filled and closed, the temperature control effect is good, and the demoulding mechanism is flexible and reliable.
e. Injection mold parts should be wear-resistant and durable. The durability of injection mold parts affects the service life of the whole injection mold. Therefore, when designing such parts, we should not only put forward the necessary requirements for their materials, processing methods, heat treatment, etc., but also pin column parts such as push rod are easy to jam, bend and break, which cause most of the faults of injection mold. For this reason, we should also consider how to adjust and replace conveniently, but we should pay attention to the adaptation of parts life and injection mold.