The competition in the manufacturing industry worldwide has become increasingly fierce. The ability of enterprises to provide customers with personalized high-quality products in the shortest possible time with high efficiency and low consumption has become a symbol of the competitiveness of enterprises.
The quality of the mold will directly affect the quality of the product, output, cost, new product production and the replacement cycle of the old product, the speed of enterprise product structure adjustment and market competitiveness, so the economic situation has put more and more on the quality of the mold High demands. How to improve the mold quality more reasonably is the key to the leap in manufacturing. How can molds be produced in high quality, low cost, and high efficiency for a longer period of time and with more mold times. This has increasingly become the focus of attention.
Mold quality includes the following aspects:
(1) Product quality: product size stability, compliance, product surface finish, product material utilization, etc.;
(2) Service life: on the premise of ensuring the quality of products, the number of working cycles that the mold can complete or the number of manufactured parts;
(3) The use and maintenance of the mold: whether it is the most convenient to use, easy to demold, and the production auxiliary time is as short as possible;
(4) Maintenance cost, maintenance period, etc.
Basic ways to improve mold quality:
(1) The design of the parts should be reasonable, and the best structural scheme should be selected as much as possible. The designer of the parts should consider the technical requirements and the structure of the parts must meet the manufacturability and feasibility of the mold manufacturing.
(2) The design of the mold is the most important step to improve the quality of the mold. Many factors need to be considered, including the selection of the mold material, the usability and safety of the mold structure, the processability of the mold parts and the convenience of mold maintenance At the beginning of the design, these should be considered as carefully as possible.
①The selection of mold materials not only needs to meet the customer's requirements for product quality, but also needs to consider the cost of the material and its strength within a set period. Of course, it also depends on the type of mold, the working method, the processing speed, and the main failure Factors such as form to select materials. For example: the main failure mode of the punching die is blade wear, you must choose a material with high surface hardness and good wear resistance; the punching die mainly bears periodic loads, which is easy to cause surface fatigue cracks and lead to peeling of the surface layer. The material with good surface toughness; the material with a particularly low friction coefficient should be selected for the drawing die; the material with strong thermal fatigue should be selected due to the cyclic thermal stress; for the injection mold, when the plastic parts are ABS, PP, PC For such materials, the mold material can be pre-hardened and tempered steel. When the plastic parts are high-finish and transparent materials, corrosion-resistant stainless steel can be selected. When the batch of products is large, quenched and tempered steel can be selected. In addition, it is also necessary to consider the use of mold materials with low affinity to the parts to prevent the mold from aggravating the wear of mold parts and affecting the quality of the mold.
② When designing the mold structure, try to make the structure compact and easy to operate, and ensure that the mold parts have sufficient strength and rigidity; when the mold structure allows, the corners of each surface of the mold parts should be designed as round corners to avoid stress concentration ; For the concave mold, cavity and part of the punch and core, the combined or mosaic structure can be used to eliminate the stress concentration. The elongated punch or core needs to take appropriate protective measures on the structure; for the cold punch, it should be Equipped with devices to prevent clogging of parts or waste materials (such as ejector pins, compressed air, etc.). At the same time, we must also consider how to reduce the impact of sliding fittings and frequent impact parts on the quality of the mold caused by long-term wear.
③In the design, the scope of disassembly and assembly must be reduced when repairing a part, especially when the wearing parts are replaced, the disassembly and assembly scope should be reduced as much as possible.
⑶ The manufacturing process of the mold is also an important part of ensuring the quality of the mold. The processing method and processing accuracy in the mold manufacturing process will also affect the service life of the mold. The accuracy of each part directly affects the overall assembly of the mold. In addition to the influence of the accuracy of the equipment itself, it is necessary to improve the processing accuracy of the parts and the technical level of the fitter in the mold grinding process to improve the processing accuracy of the mold parts. ; If the overall assembly effect of the mold does not meet the requirements, the chance of the mold operating in an abnormal state will be increased in the trial mold, which will have a great impact on the overall quality of the mold. Luo Baihui, an expert in the mold industry, pointed out that in order to ensure that the mold has good original accuracy-the original mold quality, the manufacturing process must first reasonably choose a high-precision processing method, such as EDM, wire cutting, CNC machining, etc., and should pay attention to the mold The accuracy inspection includes the machining accuracy, assembly accuracy of the mold parts and the comprehensive inspection of the mold accuracy through the mold acceptance test. During the inspection, it is also necessary to use high-precision measuring instruments. For those mold parts with complex surface and curved surface structures, if Accurate measurement data cannot be achieved with ordinary rulers and vernier cards. At this time, precision measurement equipment such as a coordinate measuring instrument needs to be selected to ensure the accuracy of the measurement data.
(4) Surface strengthening of the main forming parts of the mold to improve the wear resistance of the surface of the mold parts, thereby better improving the quality of the mold. For surface strengthening, different strengthening methods should be selected according to different molds. For example: punching die can use electric spark strengthening, hard alloy surfacing, etc., in order to improve the wear resistance and compressive strength of the surface of the mold parts; die-casting molds, plastic molds and other hot processing die steel parts can be nitrided (hard nitrogen Chemical) treatment to improve the wear resistance, heat fatigue resistance and corrosion resistance of the parts; the drawing die and bending die can be treated with sulfurization to reduce the friction coefficient and improve the wear resistance of the material; carbonitriding (Soft nitriding) can be applied to the surface strengthening treatment of various molds. In addition, a technology developed in recent years called FCVA vacuum diamond coating can form a protective film on the surface of the part that is extremely strong and very smooth, even and dense, which is particularly suitable for mold surface protection. Treatment is also a significant way to improve the quality of the mold. Of course, if the part is a trial product or the production volume is quite small, it is not necessary to carry out the surface strengthening treatment of the mold part.
(5) The correct use and maintenance of the mold is also a major factor to improve the quality of the mold. For example, the installation and debugging of the mold should be appropriate. In the case of a hot runner, the power supply wiring must be correct, the cooling water circuit must meet the design requirements, and the parameters of the injection molding machine, die casting machine, and press in the production of the mold must meet the design requirements. and many more. When using the mold correctly, regular maintenance of the mold is also required. The guide posts, guide sleeves and other parts of the mold that have relative motion should be filled with lubricating oil frequently. For molds such as forging molds, plastic molds, die casting molds, etc. Before molding, lubricant or mold release agent should be sprayed on the surface of the formed parts. Planned protective maintenance of the mold and data processing during the maintenance process can prevent problems that may occur in the production of the mold and improve the efficiency of repair work. Luo Baihui believes that in order to improve the quality of the mold, first of all, it is necessary to consider the impact on the quality of the mold at each link, and secondly, through the cooperation of various departments. The quality of the mold is a true manifestation of the mold company's own strength.
Quality is an old and often new topic! The quality of the mold, whether it is the designer and manufacturer of the mold, the designer of the part, or the user of the mold, should actively care about the problem. With the continuous innovation of technology, the widespread use of new materials, and the continuous transformation of processing technology , The difference between the use and maintenance conditions, etc. all affect the quality of the mold to varying degrees.