10 Factors Affecting The Quality Of Injection Molds

Injection mold manufacturing is a complex manufacturing process. From design, processing, assembly, debugging and other steps to the final actual use, in the entire life cycle, the factors that affect the quality of the mold mainly include the following 10 aspects.

1. Die steel

Steel is the decisive factor in mold quality, and choosing reasonable steel is the top priority. The criteria for selecting steel are:

①. Requirements for injection molding materials Different plastics should use different steel materials, such as the requirements for high polishing, corrosion resistance, etc.;

②, the price of the steel is as good as it can be used, not the more expensive the better; considering the cost factor of the mold, the mold steel should be selected according to the life of the mold to avoid unnecessary waste; the life of the general P20 material is about 300,000; 2738 material is no problem at 500,000, H13/2344 is usually more than 800,000-1 million, you can choose according to the situation;

③ Surface treatment The surface treatment of the mold is also very important. Nitriding can enhance the surface hardness of steel and effectively prolong the life of the mold; electroplating can effectively modify the mold steel, and electroplating can be used to enhance and improve the performance of steel for some plastic parts that require high brightness and corrosion resistance.

2. Structural design The mature mold structure not only takes into account the product material properties, shrinkage rate, molding temperature, elastic tensile deformation coefficient, etc. but also takes into account the cooling water channel, the speed of mold opening and closing, etc. A reasonable mold structure can effectively prolong 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 a good job, he must first sharpen his tools. The arrangement of the molding process is particularly important. A 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 stability and prolong the life of the mold in the production process. Some processing 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 movement of the mold, reduce the life of the mold, and cause the mold to crack during the production process Even broken.

4. Standard parts It is the lowest wooden strip that determines the capacity of the bucket. Everyone understands this truth, but it is often not noticed when doing it. The same is true for molds. Although standard parts do not directly participate in molding, they control the operation of the entire mold. Good standard parts should be wear-resistant, hard enough, high-precision, and not easy to deform.

5. Matching (flying mold) Matching depends on the experience of the mold fitter, and the seemingly simple work is the most technical work. The main focus of complex molds is this skill. The flat mold is the simplest, and the fractal surface is basically ok as long as there is no flash or break. For example, auto parts molds are very troublesome, not only the fractal surface is relatively irregular, but also often includes multiple sliders and top blocks. At the same time, other problems of the mold can be improved and perfected through the collision, so it is a comprehensive work.

6. Polishing/skin texture The polishing of the mold is the last link in the manufacture of the mold. Polishing is directly reflected on the plastic part, so this is the most face-saving job. Polishing can also help and supplement mold action, especially for demoulding. Often the production of some molds is not smooth because of insufficient lighting, excessive resistance, difficulty in de-molding, and even top whitening and cracking.

7. Mold assembly is like assembling a machine. Every component and every screw must not be wrong, otherwise, the consequences will be quite serious, ranging from product defects and affecting production, to completely damaging the mold and causing scrap. Therefore, the assembly work must be very meticulous. During the assembly process, we must pay special attention to the cleaning of the mold, especially the waterway and screw holes, and the iron filings inside must be blown clean.

8. Hot runner or cold runner This actually has the least impact on the quality of the mold, because the hot runner is generally the brand designated by the customer, especially some large customers. Well-known foreign brands are very good both in terms of quality and after-sales service, so there is generally no problem with quality. It's just that the quality of some domestic hot runners varies greatly. In order to save costs and strive for a price advantage, individual small companies use some unreliable heating and conduction accessories, which are prone to problems. The main problem of cold runners is how to ensure the balance of injection molding, gate size, injection molding pressure, and so on.

9. Cooling water channel Anyone who has experience in molds knows how important cooling is to a mold. Due to the increase in prices and labor wages, it is unimaginable to reduce the profit brought by the injection molding cycle by one second when producing products in large quantities. 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 form, and even the mold will be deformed, invalid, and scrapped. Therefore, excellent waterway design is particularly important, including the arrangement of density, diameter, and links between waterways, etc.

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, the mold may be scrapped. Therefore, every time the mold is used, comprehensive maintenance must be carried out, especially the rust prevention of the forming part and the rust prevention of the main moving parts. Because the mold needs to receive water during the production process, it may get stuck on the mold during the installation or disassembly process, so it is necessary to ensure that the mold is dry, and then apply a layer of oil protection.