What is the difference between low pressure injection molding and high pressure injection molding?
2018-06-07 18:40:17 Author:SystemMaster
The low-pressure injection molding process, with its unparalleled advantages, has been increasingly used in various industrial fields in recent years, and gradually replaced the traditional high-pressure injection molding process. For this injection molding process, many people are still relatively unfamiliar with traditional technologies. What is the difference between the high-pressure injection molding process, the following winstar Xiaobian for everyone to introduce the difference between low-pressure injection molding and high-pressure injection molding process and the advantages of low-pressure injection molding.
Hot melt material and injection method are different
First, low-pressure injection molding is not the same as the material used in traditional injection molding machines. The viscosity of the hot melt adhesive for low pressure injection molding is very low, and the material has high fluidity after hot melting and does not need to be extruded by the screw. It can be made to flow by the gear pump as long as it is heated and melted by the glue cylinder, with a small pressure. Into the mold with a small space, then cool the mold. Therefore, the low pressure injection molding machine does not have a screw device, and the injection glue is injected through the gear pump and the hose and the glue gun. This is a very good protection for some fragile components, which greatly improves the work efficiency.
Heating pressure, temperature is different
Low-pressure injection molding is injection molding by preheating the hot melt adhesive. Traditional injection molding minimizes the pressure, the viscosity of the material is large, and there may be insufficient plastic injection, that is, the lack of glue. Low-pressure injection molding materials have good adhesive properties and are unmatched by conventional engineering plastics. In the following table, it can be seen that the temperature of the low-pressure injection molding process is much lower than the traditional high-pressure injection molding, which can effectively reduce the probability of some precision instruments being damaged due to high temperatures.
Traditional high-pressure plastic injection:
Injection pressure (up to 350-1300 Bar);
Injection temperature is high (230-300°C);
The mould can only be made of steel;
Can not glue precision electronic components;
The glue injection machine is driven by hydraulic pressure, which is not conducive to environmental protection;
Poor adhesion of rubber and product;
Low pressure injection molding process:
Injection pressure is low (1.5-40 Bar);
Injection temperature is low (180-240°C);
Mold can use a variety of materials;
Ideal production process for sensitive and precise components;
The glue injection machine is driven by air pressure and has no pollution to the environment;
Adhesive and product have good adhesiveness and high waterproof sealing performance;
Finally, low-pressure injection molding temperatures are low, and some other materials, such as cast aluminum molds, can be used. Compared with the steel mold, it is more convenient for the design, development and processing of the grinding tool, and at the same time, the development cycle of the mold is greatly shortened. In addition, compared with the time-consuming traditional high-pressure injection molding, the low-pressure hot melt adhesive injection molding process cycle can be reduced to several seconds to tens of seconds, greatly promoting the production efficiency.