Powder injection molding is a new type of molding technology for parts formed by combining traditional powder metallurgy technology with modern plastic injection molding technology. The biggest feature of this technology is that it can directly manufacture parts with the final shape, which minimizes the amount of machining and saves raw materials, and solves the problem of difficult forming of complex-shaped products in the field of powder metallurgy; and the technology has wide material adaptability , Any metal, alloy, ceramic, etc. that can be made into powder can be made into parts by this technology. In addition, this technology can also achieve fully automated continuous production, with excellent material properties and high product dimensional accuracy.
The basic process of this technology is: first, the solid powder is uniformly mixed with certain additive components, and after granulation, the granular material is injected into the mold cavity by an injection molding machine in a heated state to condense and form, and then chemical or thermal decomposition is used. The binder in the formed blank is removed, and finally the final product is obtained by sintering and densification.
In recent years, the development of microsystem technology in various fields has been very rapid, and it has also put forward higher requirements for the manufacture of three-dimensional micro-complex components used in micro-engineering. achieve large-scale production. The main components in the microsystem include micro-molds, micro-mechanical structures for sensors and accelerators, biosensors, micro-fluidic elements, micro-reactors, etc. These components are complex in shape and small in size. The existing micro-processing technologies such as micro-cutting, laser cutting, silicon etching technology, etc., have low production efficiency and cannot be mass-produced. In recent years, they have developed on the basis of powder injection molding. The powder micro-injection molding process provides the most potential preparation technology for realizing the large-scale production of micro components.
At present, the main countries that carry out research on this technology internationally are Germany, Japan, Singapore, the United States and the United Kingdom. Among them, Germany took the lead and achieved outstanding results. The domestic University of Science and Technology Beijing, Central South University and Dalian University of Technology have also carried out a series of research work in this field. For example, Beijing University of Science and Technology has developed a powder micro-injection molding mold with independent intellectual property rights and is suitable for traditional injection molding machines; and using carbonyl iron powder and iron-nickel alloy powder as raw materials, powder micro-injection molding has been successfully realized on traditional injection molding machines. Micro gears with tip circle diameter less than 1 mm.
