Sintering is the last step in the MIM process. Sintering eliminates voids between the powder particles, making the MIM product fully densified or nearly fully densified. In the metal injection molding technology, since a large amount of binder is used, the shrinkage during sintering is very large, and the linear shrinkage rate generally reaches 13% to 25%, so that there is a problem of deformation control and dimensional precision control. This problem is particularly acute because MIM products are mostly shaped parts of complex shapes, and uniform feeding is a key factor in dimensional accuracy and deformation control of the final sintered product. The high powder shake density reduces the sintering shrinkage and also facilitates the sintering process and dimensional accuracy control. For products such as iron-based and stainless steel, there is also a carbon potential control problem in sintering. Due to the current high price of fine powder, the research on the strengthening sintering technology of coarse powder compact is an important way to reduce the production cost of powder injection molding. This technology is an important research aspect of metal powder injection molding research.

Due to the complex shape and large shrinkage of MIM products, most products still need to be post-sintered after sintering, including shaping and heat treatment (carburizing, nitriding, carbon-nitrogen osmosis, etc.), surface treatment (fine grinding, ion nitrogen). Chemical, electroplating, shot peening, etc.).