Characteristics of Metal Injection Molding Technology

Characteristics of Metal Injection Molding Technology

Metal injection molding (MIM) is a new powder metallurgy near-net forming technology that extends from the plastic injection molding profession. It is well known that the MIM technology can produce products of various disorderly shapes at low prices, but the strength of plastic products is not high. In order to improve its function, metal or ceramic powder can be added to plastics to obtain products with high strength and good wear resistance. In recent years, this idea has evolved into limiting the content of solid particles and thoroughly removing the binder in the subsequent sintering process and making the forming billet finer. This new powder metallurgy forming method is called metal injection molding.

Chinese name Metal injection molding Foreign language name Subject product field Plastic injection molding Professional molding method Powder metallurgy

The basic process of metal injection molding is: first, select the metal powder and binder that meet the requirements of MIM, and then select the appropriate method to mix the powder and binder into a uniform feed at a certain temperature. After granulation, the injection molding is carried out. The formed blank is sintered and refined into a finished product after degreasing treatment.

The requirements for material powder are high, and the selection of powder should be conducive to mixing, injection molding, degreasing and sintering, which are often contradictory. The study of MIM material powder includes: powder shape, particle size and particle size composition, specific surface, etc. Table 1 lists the properties of material powder suitable for MIM.

Due to the fine requirements of the MIM material powder, the price of the MIM material powder is generally high, some of which even reach 10 times the price of the traditional PM powder. This is a key factor for the wide application of the technology. The methods of producing the MIM material powder mainly include carbonyl method, ultra-high-pressure water atomization method, high-pressure gas atomization method, etc.