Mold is the mother of industry, and the development of the mold industry is closely related to the entire industrial level. With the progress of technology, the requirements for molds are also constantly increasing, so we must focus on the quality of molds when manufacturing them. The following are the key points for improving the quality of precision injection molding.
The structure should be optimized, and the designer must consider the producibility and plasticity during the design.
This includes the selection of mold materials, the availability and safety of the mold structure, the machinability of precision mold parts, and the convenience of mold maintenance. These should be considered as comprehensively as possible at the outset.
The choice of mold materials must meet customer requirements for product quality and consider the cost of materials and their strength within the set period. The choice of materials should also be based on the type of mold, working mode, processing speed, and main failure modes. For ABS, PP, PC and other materials, pre-hardened and tempered steel can be selected as the mold material; for materials that require high gloss and transparency, corrosion-resistant stainless steel can be selected; for large-scale production, quenched and tempered steel can be chosen. In addition, mold materials with low affinity to molded parts should be selected to prevent excessive sticking and wear of mold parts, which can affect the quality of molds.
When designing mold structures, the structure should be as compact and easy to operate as possible, and ensure that the mold parts have sufficient strength and rigidity. When possible, the corners of the surfaces of each mold part should be designed as rounded to avoid stress concentration. For concave molds, cavities, and some convex molds and cores, a combination or splicing structure can be used to eliminate stress concentration. For long and slender convex molds or cores, appropriate protective measures should be taken in the structure. For cold heading molds, devices that prevent workpiece or waste blockages, such as pop-up pins and compressed air, should be configured. At the same time, it is also necessary to consider how to reduce the wear and tear of sliding mating parts and frequent collision parts during long-term use, which can affect the quality of molds.
In the design, the scope of disassembly and assembly must be reduced when maintaining a certain component, especially when replacing vulnerable parts, the scope of disassembly and assembly should be reduced as much as possible.
The precision of each part directly affects the overall assembly of the mold. In addition to the influence of the precision of the equipment itself, it is necessary to improve the processing method of the parts and the technical level of the fitter in the mold grinding process to improve the machining precision of the mold parts. ; If the overall assembly effect of the mold does not meet the requirements, it will increase the probability of the mold moving in an abnormal state during the mold trial, which will have a great impact on the overall quality of the mold. Reasonably choose high-precision processing methods, such as EDM, wire cutting, CNC machining, etc. At the same time, attention should be paid to the accuracy inspection of the mold, including the machining accuracy of mold parts, assembly accuracy and comprehensive inspection of mold accuracy through mold test acceptance work. When inspecting, it is necessary to use high-precision measuring instruments as much as possible. For those mold parts with complex surface structures, ordinary rulers and vernier cards cannot achieve accurate measurement data. At this time, it is necessary to use a three-coordinate measuring instrument. Class precision measuring equipment to ensure the accuracy of measurement data.
Plastic mold steel parts can be treated with nitriding (hard nitriding) to improve the wear resistance, thermal fatigue resistance and corrosion resistance of the parts; drawing dies and bending dies can be treated with sulfurization to reduce the friction coefficient, Improve the wear resistance of the material; carbonitriding (soft nitriding) can be applied to the surface strengthening treatment of various molds.
When the injection molding is used correctly, it is necessary to carry out regular maintenance on the mold. The guide post, guide sleeve and other parts with relative movement of the mold should be filled with lubricating oil frequently. For molds such as forging molds, plastic molds, and die-casting molds Lubricant or mold release agent should be sprayed on the surface of the formed part before each mold is formed. Planned preventive maintenance of molds and data processing during maintenance can prevent possible problems in mold production and improve maintenance efficiency.
In short, in order to improve the quality of injection molding, first of all, every link must take into account the impact on the quality of the mold, and secondly, it must cooperate with all departments. The quality of the mold is the true embodiment of the precision moulding company's own strength.