Mold manufacturing process is a complex process, from the design, processing, assembly, debugging and other steps, and finally can be put into use. In the whole life cycle, the factors affecting mold quality mainly include the following ten aspects:
1. Die steel
Several common steels
Steel is the decisive factor of die quality, and the most important thing is to choose a reasonable steel. The criteria for steel selection are:
① Requirements for injection molding materials - different plastics shall be made of different steels, such as high polishing requirements, corrosion resistance requirements, etc;
② Price - steel can be used, not the more expensive the better; considering the cost factor of the mold, the mold steel should choose the material corresponding to the mold life to avoid unnecessary waste; the life of P20 is generally about 300000; 2738, 500000 is no problem, H13 / 2344 is usually more than 800000-1 million, which can be selected according to the situation;
③ Heat treatment. Mold surface treatment is also very important. Nitriding can enhance the surface hardness of steel and effectively extend the service life of die; electroplating can effectively modify die steel, and electroplating can be used to enhance and improve the performance of steel for some plastic parts requiring high brightness and corrosion resistance
2. Structural design
Structural design of pipe fittings
The mature die structure not only takes into account the product material properties - shrinkage, molding temperature, elastic tensile deformation coefficient, but also takes into account the cooling water path, opening and closing speed of the die. Reasonable die structure can effectively extend the life of the die and ensure the smooth production of the die. Improve efficiency and reduce cost.
3. Mold processing
Sharp tools make good work. It is very important to arrange the die process. Reasonable process arrangement can speed up the production cycle, shorten the processing time and save the cost effectively. And more importantly, accurate and reasonable processing can ensure the stability of the mold in the production process and extend the life. Some processing errors will lead to die Burning and welding, no matter how good the welding is, it is a loss for the die; in addition, poor processing may affect the action of the die, reduce the life of the die, and cause the die to crack or even break in the production process.
4. Standard parts
The lowest stick determines the capacity of the bucket. We all understand this principle, but we often fail to notice it when we do it. The mold is the same. Although standard parts do not directly participate in the molding, they control the operation of the whole mold. Good standard parts should be wear-resistant, hard enough, high precision and not be deformed. There is a big price difference between standard parts of different brands, so don't just haggle over the price of making molds. Your molds will drop from Mercedes Benz to the public.
5. Collision (flying mold)
The experience of the die fitter is the opposite. The seemingly simple work is the most technical work. This is the main focus of complex mold. The plate mold is the simplest. As long as the fractal surface has no flash and fracture difference, it is OK. Like auto parts mold is very troublesome, not only the fractal surface is irregular, but also often includes multiple sliders and top blocks. At the same time, other problems of the die can be improved and perfected through the collision. So it is a comprehensive work.
6. Polishing / Dermatoglyphics
Mold polishing is the last step of mold manufacturing. Polishing is directly reflected on the plastic parts, so this is the most face-saving work. Polishing can also help and supplement the mold action, especially for demoulding. Often some mold production is not smooth because the polishing is not in place, the resistance is too large, demoulding is difficult, even top white, top crack and so on.
7. Mold assembly
Mold assembly is like assembly machine. Every part and screw should not make mistakes. Otherwise, the consequences will be quite serious. Light will lead to product defects, affect production, heavy will completely damage the mold, resulting in scrap. So the assembly work must be very meticulous. In the assembly process, especially pay attention to the cleaning of the mold, especially the waterways and screw holes. Be sure to blow out the iron chips inside, or the customer will be very angry.
8. Hot runner or cold runner
In fact, this has the least impact on the quality of the mold, because the hot runner is generally designated by the customer, especially some big customers. Foreign well-known brands do a good job in quality and after-sales service, so there is generally no problem in quality. But the quality of some hot runner in China is quite different. In order to save costs and strive for price advantages, some small enterprises are prone to problems by using unreliable heating and conduction accessories. The main problem of cold runner is how to ensure the injection balance, gate size, injection pressure and so on. 9. Cooling water circuit
People who have experience in mold know how important cooling is to a mold. Due to the increase of price and labor wage, it is impossible to imagine the profits brought by the injection molding cycle without one second reduction in mass production. But at the same time of speeding up the production cycle, it will be the rise of mold temperature. If it can not be effectively controlled, it will make the mold too hot to form, and even lead to die deformation failure and scrap. Therefore, the excellent design of waterway is particularly important, including the layout density, diameter, links between each other and so on.
10. Mold maintenance
Mold maintenance is mainly in the production process of maintenance and maintenance. The mold is like a car, if it is not used for a long time without maintenance, it may lead to die scrapping. Therefore, every time the mold is used, comprehensive maintenance should be carried out, especially the rust prevention of the forming part and the main action parts. Because the mold needs to be connected with water in the production process, it may get on the mold during the installation or disassembly process, so it is necessary to ensure the mold is dry, and then brush a layer of oil for protection.