The external and internal shapes of injection molded parts are directly formed by the mold cavities and cores. These complex three-dimensional surfaces are relatively difficult to process, especially the forming surfaces in blind holes in the mold cavities. If traditional injection mold manufacturing methods are used, the injection mould maker must have a high level of technical expertise, require many auxiliary fixtures and tools, and have a long injection moulding mold manufacturing cycle.
Currently, the dimensional accuracy of general injected parts is IT6-7, and the surface roughness is Ra0.2-0.1m. The corresponding dimensional accuracy of injection mold parts is required to reach IT5-6, and the surface roughness Ra is less than 0.1m. The surface roughness of the laser disc recording should reach the mirror processing level of 0.02-0.01m, and the surface roughness of the mold should be less than 0.01m.
Injection moulding molds are very important for improving injection efficiency and reducing the injection cost of large-scale injections. Currently, the service life of injection molds generally requires more than one million times. Precision injection molds use rigid mold bases, increase the thickness of the mold plate, add support columns, or taper positioning elements to prevent the mold from deforming under pressure. Sometimes the internal pressure can reach 100 MPa. The ejector device is an important factor that affects the deformation and dimensional accuracy of the injection molded product, so the best ejector point should be selected to ensure uniform demolding. Most high-precision injection molding moulds are manufactured inlaid or fully assembled in the structure, which greatly improves the machining accuracy and interchangeability of mold parts.
For injection molding supplies, most parts match other injection molded parts to form a complete product. In many cases, other parts have been completed and urgently need to wait for the injection molding parts to be launched. Because the requirements for the shape or dimensional accuracy of injection molded products are very high, and because of the different characteristics of resin materials, it is necessary to repeatedly test and correct the molds after injection molding. Therefore, the delivery time for the development and manufacture of injection molds is tight.
Plastic injection molds for sale is not the ultimate goal, but the product design is proposed by the product company. Injection mould makers design and manufacture injection molds according to the requirements of the product company. In some cases, mold design and injection molding of injection products are not in the same injection molding factory. This has led to the design of injection parts, mold design and mold manufacturing, and injection molding being carried out in different injection molding factories.
Small batch plastic injection mould making usually belongs to the manufacture of individual molds. However, injection molding moulds require many standard mold parts, from mold bases to small ejector pins. These cannot be completed by a single manufacturer and the manufacturing process is complex, with uneven use of general equipment and CNC equipment.