Mold manufacturing is a complex process, from design, processing, assembly, debugging and other steps, after the debugging is qualified, it can be put into massive production. In the whole mold life cycle, the factors affecting mold quality mainly include the following ten aspects:
1. Mould steel:
Steel is the decisive factor of mold quality, and choosing a reasonable steel is the top priority.
①Requirements for injection molding materials—different plastics should use different steels, such as high polishing requirements, corrosion resistance requirements, etc.
②Pricing—the 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, and unnecessary waste should be avoided, Generally the mold life of P20 is 150,000 shots,2738 (steel) about 150,000 to 350,000 shots,H13/2344 is usually more than 350,000 shots,you can choose 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 and extend the mold life.
Electroplating—It can effectively modify the mold steel. For some plastic parts that require high brightness and corrosion resistance, electroplating can be used to enhance and improve the performance of the steel.
2. Structural design:
An advanced mold structure design is not only to consider the product material properties, forming temperature, elastic tensile deformation coefficient, but also to consider shrink the cooling water and the mold speed of opening and closing.A reasonable mold structure can extend the mold life effectively and ensure the smooth production. (*Improve efficiency-Reduce the cost)
3. Mold processing:
The arrangement of the mold process is particularly important. A reasonable process arrangement can speed up the production cycle, shorten the processing time, and effectively save costs. More importantly, accurate and reasonable processing can ensure the stability and extend the mold life when processing.Some processing errors will cause mold welding, no matter how good the welding is, it is a kind of damage to the mold. In addition, poor processing may affect the mold operation, reduce the mold life, and cause the mold to crack during the production process.
4. Standard parts:
Although standard parts do not directly participate in the forming part, they control the operation of the entire mold. Good standard parts should be abrasion-resistant, hard enough, high precision, and not deformation. There is a big price difference between standard parts of different brands, so do not blindly ask for a price reduction when making molds. You must always believe that the price of good steel is transparent in the market, and we are determined not to be shoddy.
5. Fitting mold:
Seemingly simple work is the most technical work. The flat mold is the simplest, as long as the PL line has no flashing, it is basically ok. For automobile parts or complex product shape is very troublesome, not only the PL line is more irregular, but also contains multiple slider and block. Through mold fitting can improve other mold problems, so it is a comprehensive work.
Mold polishing is the last series in mold manufacturing. It is the most important job as it's reflected on the plastic parts directly. Polishing can also play a role in smooth operation of the mold, especially for demolding. Some molds production is not smooth because of improper polishing, excessive resistance, difficulty in demolding, and even deformation and cracking.
7. Mold assembly:
Mold assembly is just like assembling a machine. Every component and every screw must not be wrong, otherwise consequences will be very serious. It will cause product defects and affect the production or at the worst, the mold will be completely damaged and scrapped. Therefore, the assembly work must be very meticulous. In the assembly process, pay special attention to the cleaning of the mold, especially the water tube and screw holes, and be sure to remove the iron filings/debris inside.
8. Runner system:
Hot runner or cold runner actually has the least impact on mold quality, because hot runners are generally designated by customers, especially some large customers. Well-known foreign brands are very good in quality and after-sales service, so there is generally no problem in quality. The main problem of cold runner is how to ensure the balance of injection molding, gate size, injection pressure and so on.
9. Cooling system:
Anyone who has experience in molds knows how important cooling is a mold. Due to rising prices and labor wages, the profit of reducing the injection cycle by one second is unimaginable when go to massive production. However, speeding up the production cycle will also cause the mold temperature to rise. If it is not effectively controlled, the mold will be too hot to form, and even cause the mold to deform or damage. Therefore, good water tube design is particularly important, Including the layout of water tube density, diameter and links between each other.
10. Mold maintenance:
Mold maintenance is mainly in the production process of maintenance. The mold is like a car, if it is not used for a long time without maintenance, it may cause the mold to rust and be scrapped. Therefore, every time the mold is used, a comprehensive maintenance must be carried out, especially the rust prevention of the forming part and the main moving parts. Because the mold needs to receive water during the production process, it may be blown on the mold during the installation or disassembly process, so you must ensure that the mold is dry, and then apply a layer of anti-rust oil to protect it.