Compared with other types of mold such as stamping mold and die casting mold, injection mold tool manufacture has five obvious characteristics. The analyses are as follows:
1. The cavity and core of the injection mold tool manufacture are three-dimensional
The external and internal shapes of the plastic part are directly formed by the cavity and core. These complex three-dimensional molded surfaces are more difficult to process, especially the processing of blind-hole inner molded surface of the injection mold manufacturing cavity. If traditional processing method is used, it not only requires workers with high technical level, lots of auxiliary clamping apparatus and cutters, but also requires a long processing cycle.
2. The requirements on the precision and surface quality of injection mold tool manufacture are high, and its service life should be long.
At present, the dimensional accuracy of general plastic parts is required to be IT6-7, and the surface roughness is Ra0.2-0.1μm. The corresponding dimensional accuracy of injection mold tool manufacture is required to reach IT5-6, and the surface roughness is less than Ra0.1μm.
The roughness of the recording surface of the laser disk must reach 0.02-0.01μm, which is the level of mirror processing, so it requires the surface roughness of the mold to be below 0.01μm.
In terms of long-life injection mold, it is necessary to improve efficiency and reduce costs. At present, the service life of injection mold generally requires more than 1 million times of use. Precision injection mold needs to be equipped with a rigid mold base, and it is necessary to increase the thickness of the mold board, and add support columns or tapered positioning elements to prevent the mold from deforming after pressure. Sometimes the internal pressure can reach 100MPa.
The ejector is an important factor that affects the deformation and dimensional accuracy of the product, so the best ejector point should be selected to make the demolding uniform everywhere. Most of the high-precision injection mold tool manufacture adopts inlaid or full-assembled structure, which requires the processing accuracy and interchangeability of mold parts to be greatly improved.
3. The technological process of injection mold tool manufacture is long and the manufacturing time is limited
Mold experts believe that for injection molded parts, most of them are matched with other parts to form a complete product. And in many cases, other parts have been completed, and the matching of injection molded parts are desired to come into the market. Because of the high requirements of our custom plastic injection molding companies for the shape or dimensional accuracy of the products and the different characteristics of the resin materials, after the injection molding tool is manufactured, it is necessary to repeatedly try and correct the mold, which makes the development and delivery time very limited.
4. Design and manufacturing of injection mold tool manufacture in different places
Injection mold tool manufacture is not the final goal, but the final product design proposed by the user. The injection mold tool manufacturers design and manufacture the mold according to the user’s requirements. And in most cases, the injection production of the product is also carried out by other manufacturers. This results in a situation that product design, the design and manufacturing of mold, and product production are carried out in different places.
5. Professional division of labor and dynamic combination of injection mold tool manufacture
The production batch of mold is small and generally the mold adopts the single-piece production. But mold requires many standard parts, ranging from mold bases to small ejector pins. These cannot be completed by one manufacturer alone, and the technology of injection mold tool manufacture is complex. The usage of common equipment and CNC equipment is extremely uneven.