Plastic injection molds and plastic molding machines are tools used together to ensure that plastic products have complete configuration and accurate dimensions.
There is a wide range of injection moulding products and processing methods., and plastic molding machines and plastic products will have many structures, so the types and structures of plastic injection molds are also diverse. So, what do we need to pay attention to when using plastic injection molds?
Plastic injection mold processing is mainly divided into four parts, namely the forging process, preheating treatment, quenching and tempering, stress relief annealing. Below we will introduce the attention points of each link.
1. Forging process. This is an important link in the manufacturing process of working parts of plastic injection molds. For plastic injection molds of high alloy tool steel, technical requirements are usually put forward for the carbide distribution of the material. In addition, the forging temperature range should be strictly controlled, the correct heating specifications should be formulated, the correct forging force method should be adopted, and the forging should be cooled slowly or annealed in time.
2. Preheat treatment. According to the different materials and requirements of the plastic injection mold working parts, preparatory heat treatment processes such as annealing, normalizing or quenching and tempering should be used to improve the structure, eliminate the structural defects of the forging blank, and improve the processing technology. After proper preheating treatment of high-carbon alloy die steel, the reticulated secondary cementite or chain carbide can be eliminated, the carbides can be spheroidized and refined, and the uniformity of carbide distribution can be promoted. This is conducive to ensuring the quality of quenching and tempering and improving the life of the mold.
3. Quenching and tempering. This is the key link in the heat treatment of the mold. If overheating occurs during quenching and heating, it will not only cause greater brittleness of the workpiece but also easily cause deformation and cracking during cooling, which will seriously affect the life of the mold. When the die is quenched and heated, special attention should be paid to preventing oxidation and decarburization, and the heat treatment process specification should be strictly controlled. When conditions permit, vacuum heat treatment can be used. After quenching, it should be tempered in time, and different tempering processes should be adopted according to technical requirements.
4. Stress relief annealing. The plastic injection mold should be subjected to stress relief annealing after processing the parts in order to eliminate the internal stress caused by rough machining so as to avoid excessive deformation and cracks caused by quenching. For moulds with high precision requirements, stress relief tempering is required after grinding or electrical machining, which is conducive to stabilizing mold accuracy and improving service life.
1. High manufacturing precision. In order to produce qualified products and develop the skills of plastic injection molds, the design and manufacture of plastic injection molds must have high precision. The accuracy of plastic injection molds is mainly determined by product accuracy requirements and mold structure. In order to ensure the accuracy and quality of materials, the accuracy of the working part of plastic injection molds is usually 2 to 4 levels higher than that of products. The structure of the plastic injection mold has higher requirements on the cooperation between the upper and lower molds. The components that make up the plastic injection mold must have sufficient manufacturing accuracy. Otherwise, the plastic injection mold will not be able to produce qualified products and even will. As a result, the plastic injection mold cannot be used normally.
2. Long service life. Plastic injection mold is relatively expensive process equipment. At present, the manufacturing cost of plastic injection mold accounts for about 10% to 30% of the product cost, and its service life will directly affect the production cost. Therefore, except for special cases such as small batch production and trial production of new products, plastic injection molds are generally required to have a long service life. In the case of mass production, the service life of plastic injection molds is more important.
3. The manufacturing cycle is short. The length of the plastic injection mold manufacturing cycle is mainly determined by the level of manufacturing technology and production management. In order to meet the needs of production and improve the competitiveness of products, it is necessary to shorten the manufacturing cycle of plastic injection molds as much as possible on the premise of ensuring quality.
4. Low production cost. The cost of plastic injection mold is related to the complexity of the mold structure, mold material, manufacturing accuracy requirements, and processing methods. Plastic injection mold designers must reasonably design and formulate their processing technology according to product requirements and strive to reduce mold manufacturing costs.