1. In-depth analysis of the structure and technical requirements of plastic parts. Plastic parts structure determines the complexity of the structure of injection mold, plastic parts of the technical requirements (such as dimensional accuracy and surface roughness) determines the injection mold making and molding process easily, so for to do not meet the special requirements of plastic injection molding, such as unreasonable structure shape, all should put forward the improved design scheme of injection molded parts, otherwise it will increase the injection mold design and manufacturing and the difficulty of the injection molding process.

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

        3. Understand the processing and technological properties of plastics. Line including the plastic melt flow, melt flow can achieve greater distance than: analysis of the flow channel and flow resistance in all parts of the cavity, the cavity within the original air discharge, plastic crystallization may occur in the injection mold, orientation and cause of stress, plastic cooling contraction and compensation, plastic requirement for injection mould temperature, etc.

        4, consider the injection mold design and manufacturing, 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 the appropriate molding methods and equipment, combined with the factory's mechanical processing capacity, put forward the structure of injection mold, fully solicit the opinions of relevant parties, analysis and discussion, so that the designed injection mold structure is reasonable, reliable quality, easy to operate. When necessary, according to the needs of injection mold design and processing, put forward the requirement of modifying plastic parts drawing, but it can only be implemented after obtaining the user's consent.

        B. The dimensions of injection molding parts should be calculated correctly. Forming part is a direct factor to determine the shape, size and surface quality of plastic parts. The average shrinkage rate method can be used to calculate the size of forming parts. For plastic parts with high precision and need to control the mold allowance, it can be calculated according to the tolerance zone method. For large precision plastic parts, it can be calculated by using the analogy method 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 theoretically.

        C. The designed injection mold shall be convenient to manufacture. When designing injection mold, try to make the design of injection mold manufacturing easy and cheap. Especially for those more complex forming parts, it must be considered whether to use the general machining method processing or using a special machining method processing. If the use of special processing methods, then how to do the assembly after processing, similar problems in the design of injection mold should be considered and solved, but also should take into account the mold after the trial, to have enough mold allowance.

        D. The injection mould designed should be efficient, safe and reliable. This requirement involves many aspects of injection mold design, such as filling system, closed module, good effect of temperature adjustment, and flexible and reliable demounting 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, so in the design of this kind of parts should not only its materials, processing methods, heat treatment, etc., put forward the necessary requirements, such as push rod pin column is also easy to get stuck, bend, break, so the fault caused by the majority of injection mold fault. Therefore, we should also consider how to adjust and replace conveniently, but we should pay attention to the parts life and injection mold.

        F. The injection mold structure should adapt to the molding characteristics of plastics. In the design of injection mold, should fully understand the plastic molding characteristics and try to meet the requirements, which is also an important measure to obtain high quality plastic parts.