What are the characteristics of injection molds?
plastic injection mold
1. The cavities and cores are three-dimensional.
The cavity and core directly form the inner and outer shape of the plastic part. These complex three-dimensional surfaces, especially the blind holes in the cavity, are very difficult to process. The traditional processing method requires high skill level of workers, and more auxiliary tools and long processing time.
2. It has high requirements for precision and surface quality, and also requires long service life.
At present, the general dimensional accuracy of plastic parts required for it6-7, surface roughness of ra0.2-0.1μM, the corresponding injection mold parts require dimensional accuracy of it5-6, surface roughness less than ra0.1μM, the surface roughness of the laser disk should reach the level of 0.02-0.01μM using mirror processing, requiring the mold surface roughness less than 0.01μM. In order to improve efficiency and reduce costs, injection molds with long service life are needed. At present, the injection mold needs to have a service life of using more than 1 million times. In order to prevent the injection mold from deformation under pressure, rigid mold frame should be used, increase the mold thickness, and add support columns or conical positioning elements.
The important factor that affects the deformation and dimensional accuracy of the product is the ejector device, the ejector point should be well chosen to ensure uniform demoulding. Most of the high-precision injection molds adopt inlay or fully assembled structure, which requires the machining accuracy and interchangeability of mold parts to be greatly improved.
3. The processing process is long, the process of manufacturing time is tight.
Mold expert Luo Baihui believes that for injection molded parts, most of them form complete products with other parts, and in many cases, they are waiting for the launch of injection molded parts after other parts are completed. The shape or dimensional accuracy of the product requires high precision, and the resin material has different characteristics. After the mold manufacturing is completed, the mold needs to be tested and modified repeatedly, so the mold development and delivery time is very tight.
4. Off-site design and manufacturing.
Mold manufacturing is not the final goal, but the final product design proposed by the user. The mold manufacturer designs and manufactures the molds according to the user’s requirements, and in most cases, the products produced by injection molding are also produced in other manufacturers.
Because the production batch of molds is relatively small and generally produced in a single piece, but the production of a set of molds requires a large number of standard parts, including mold frames, ejector pins, etc. These are not possible for only one manufacturer to manufacture, and its process manufacturing complex, the use of ordinary equipment and CNC equipment is extremely unbalanced.
