Several common problems of injection mold
- 2020-04-07-

We know that many household products are made of plastic, and many of them are made by injection molding. Do you know how to produce such colorful plastic products? In fact, the raw materials we use in general production Both are transparent and translucent polyethylene and polypropylene. The final color we use coloring technology to fix the color. The general coloring methods include compound coloring technology, dry toner coloring method and so on. Among them, the compound coloring technology is suitable for small batch production, which can produce accurate, high repeatability and deep and deep injection products. The dry toner coloring method is also relatively cheap, and the dust-absorbing color is uniform and accurate when used. A bag or carton of a specific size can be used to load the correct amount of dry toner.

In the production process, there will be cracks in the products. Then you know how it is caused and how to solve it. The reason is that during the injection molding process, the gate is stuck in the gate sleeve and it is not easy to come out. When the mold is opened, the product will crack and damage. In addition, the operator must knock out the tip of the copper rod from the nozzle before demolding to make it loose, which seriously affects the production efficiency. The main reason for this failure is the poor finish of the gate cone hole, and there are knife marks around the inner hole. Secondly, the material is too soft, the small end of the tapered hole is deformed or damaged after a period of use, and the spherical curvature of the nozzle is too small, causing the gate rivet head here. The taper hole of the gate sleeve is difficult to process, and standard parts should be used as much as possible. If you need to process it yourself, you must make or buy a reamer yourself. The cone hole should be polished to below Ra0.4. In addition, a gate lever or gate ejection mechanism must also be provided.

When the mold is injected, the molten plastic in the mold cavity will generate a large back pressure, generally 600 ~ 1000kg / cm ~ 2. Sometimes manufacturers do not pay attention to this problem and often change the original design size, or use low-strength steel plate instead of mobile formwork. In the mold with ejector pin, due to the large span of the seat on both sides, the template will bend during the injection process. Therefore, the mobile formwork must use high-quality steel with sufficient thickness. Low-strength steel plates such as A3 are not provided. When necessary, set up supporting columns or blocks under the mobile formwork to reduce the thickness of the formwork and increase the bearing capacity.