Ten factors affecting the quality of injection molds
The mold manufacturing process is a complicated process. From the steps of design, processing, assembly, debugging, etc., it can be finally put into use. In the whole life cycle, the factors affecting the quality of the mold mainly have the following ten aspects:
1. Mold steel
Several commonly used steels
Steel is the decisive factor in the quality of the mold, and choosing the right steel is the top priority. The criteria for choosing steel are:
1 requirements for injection molding materials - different plastics should use different steels, such as requirements for high polishing, corrosion resistance, etc.;
2 price - steel can be used as well, not the more expensive the better; considering the cost of the mold, the mold steel should use the material corresponding to the life of the mold to avoid unnecessary waste; the life of the general P20 is about 300,000; 2738, 500,000 is no problem, H13/2344 is usually more than 80-100 million, and can be selected according to the situation;
3 heat treatment. The surface treatment of the mold is also very important. Nitriding - can enhance the surface hardness of steel, effectively extend the life of the mold; electroplating - can effectively modify the mold steel, for some high-brightness and corrosion-resistant plastic parts can use electroplating to enhance and improve the performance of steel
2. Structural design.
Pipe structure design
The mature mold structure not only takes into account the material properties of the product - shrinkage rate, molding temperature, elastic tensile deformation coefficient, etc., but also considers the cooling water passage, the speed of opening and closing the mold, and the like. Reasonable mold structure can effectively extend the life of the mold and ensure the smooth production of the mold. Improve efficiency and reduce costs.
3. Mold processing.
If a worker wants to do something good, he must first sharpen his tools. The arrangement of the mold process is particularly important, and the reasonable process arrangement can speed up the production cycle, shorten the processing time, and effectively save costs. And more importantly, accurate and reasonable processing can ensure the stability and longevity of the mold during the production process. Some machining errors will lead to mold welding, no matter how good the welding is, it is a loss to the mold; in addition, poor processing may affect the mold movement, reduce the mold life, and cause the mold to crack during the production process. Even broken.
4. Standard parts.
The lowest bar is the one that determines the capacity of the bucket. Everyone understands this truth, but it is often not noticed when doing it. The mold is the same, although the standard parts are not directly involved in the molding, but control the operation of the entire mold. Good standard parts should be wear-resistant, hard enough, high precision, and not suitable for deformation. Different brands of standard parts are very expensive, so don't blindly kill the mold, kill it, and your mold will drop from Mercedes to the public.
5. Touch (flying mode).
The experience of the mold fitter is against the seemingly simple work but the most technical work. The main thing about complex molds is this effort. The flat mold is the simplest, and the fractal surface is basically ok as long as there is no flash break. It is very troublesome to use a car accessory mold. Not only is the fractal surface relatively irregular, but it often includes multiple sliders and top blocks. At the same time, through the collision, other problems of the mold can be improved and improved. So it is a comprehensive job
The polishing of the mold is the last step in the manufacture of the mold. Polishing is directly reflected on the plastic parts, so this is the most face-to-face job. Polishing also helps and complements the mold movement, especially for demolding. Often some mold production is not smooth because the lighting is not in place, the resistance is too large, the demoulding is difficult, and even the white, the top crack and so on.
7. Mold assembly
Mold assembly is like assembling a machine. Every component and every screw can't go wrong. Otherwise, the consequences will be quite serious. If it is light, it will lead to product defects, affecting production, and completely damage the mold and cause scrapping. Therefore, the assembly work must be very detailed. In the assembly process, especially pay attention to the cleaning work of the mold, especially the water path and screw holes. Be sure to blow off the iron filings inside, otherwise the customer is very angry.
8. Hot runner or cold runner
This actually has the least impact on the quality of the mold, because the hot runners are generally branded by customers, especially some large customers. Well-known foreign brands do very well in quality and after-sales service, so there is generally no problem in quality. However, some domestic hot runners have a very different quality. In order to save costs, individual small enterprises strive for price advantages, and with some unreliable heating and conduction accessories, problems are easy to occur. The main problem with cold runners is how to ensure the balance of injection molding, gate size, injection pressure and so on.
9. Cool the waterway.
Anyone with experience in mold knows how important cooling is to a mold. Due to the increase in prices and labor wages, it is unthinkable to reduce the profit from the one-second injection cycle when mass-producing products. However, when the production cycle is accelerated, the temperature of the mold will rise. If it is not effectively controlled, the mold will be too hot to be formed, and even the mold deformation will be scrapped. Therefore, excellent waterway design is particularly important, including the arrangement density of waterways, diameters, links between each other, and so on.
10. Mold maintenance.
Mold maintenance is mainly maintenance and maintenance during the production process. The mold is like a car. If it is not used for a long time without maintenance, it may cause the mold to be scrapped. Therefore, every time the mold is used, it must be fully maintained, especially the rust prevention of the molded part and the rust prevention of the main moving parts. Because the mold has to be watered during the production process, it may fall into the mold during the installation or disassembly process, so be sure to dry the mold and then apply a layer of oil protection.