Powder injection molding: revolutionizing manufacturing (3)

Powder microinjection molding technology was first proposed by German and has been studied in world. As a process developed from powder injection molding, powder microinjection molding is same as conventional powder injection molding in basic process. 

Generally speaking, materials used in traditional powder injection molding can also be used in micro-injection molding, such as 316L, 17-4ph, wc-co, W, w-cu, Cu and Al2O3. Compared to traditional powder injection molding, powder micro injection molding produces smaller parts with a higher surface finish and therefore requires a finer powder (about 1 micron). Due to higher specific surface area of fine powder,  powder of microinjection molding needs to add more binder when mixing, and its surface energy is higher, and it is easier to oxidize and pollute.

In recent years, great progress has been made in application of micro-injection molding technology in forming of micro-metal and ceramic components. In particular, the application of this technology in metal forming makes micro-parts obtain high strength, good corrosion resistance, high temperature stability, excellent magnetic properties and wear resistance. 

Using this technique can save expensive assembly costs of tiny components. Some achievements have been made in powder micro-injection molding abroad. For example, IFAM research institute in Germany mainly studies micro-injection molding products applied in chemical industry, fluid industry, biological medicine, etc. It also includes making wear-resistant micro-parts and molds with hard alloy powder and co-sintering and co-connecting of two or more injection green part. Karlsruhe research center uses micro-injection molding to manufacture micro-structural components such as gears and light fixtures.

Powder injection molding technology is also have limitations, however, for example while it is possible to solve the problem of complex shapes, but because of a large amount of binder addition and removal, as a result, powder injection molding is limited to products with small size, low precision and low mechanical properties. It is not suitable for applications with high mechanical properties and sensitive to defects, such as ceramic tools and cutting tools.

In addition, micro powder injection molding uses sub-micron powder, powder is easy to spontaneous combustion, so oxidation should be avoided in process of treatment. 

To sum up, although prospects are good, there is still room for improvement.