Metal powder metallurgy is the production of metal or metal powder (or metal powder and non-metallic powder mixture) as raw materials, through the molding and sintering, the manufacture of metal materials, composite and various types of products technology.

Metal powder metallurgy products have been known as the "international hottest metal parts forming technology" one of its main processing technology has powder compression molding, powder injection molding, 3D printing molding, metal powder metallurgy products to powder as the main raw material, the characteristics of the powder to determine the process of product design, formulations, molds, molding process, Degreasing, sintering process and secondary processing, which ultimately determines the quality of the product.

Sintering was born more than 1,000 years ago and can now be used in many industries, from the widely known ceramics industry to the powder injection molding industry.

The sintering process is divided into three main stages

Initial stage, intermediate stage and final stage

After acid stripping of the raw material injected by the injection molding machine, most of the binder (POM) is removed, while a small amount of high temperature binder remains to maintain the product's morphology. This residual high temperature binder is removed by a decomposition reaction in a sintering furnace heated to 600 degrees Celsius. This stage is not the same as acid degreasing and is called the thermal degreasing stage, also known as pre-sintering.

Initial stage: A sintering neck is formed between the metal powder particles in the completely degreased embryo from the point of contact and grows.

Intermediate stage: the sintering neck grows and the gap between the metal powder particles gradually decreases, forming a network of pores connected by grain boundaries.

Final stage: The pores between the particles eventually become closed and independent pores, and the product is molded.

After the sintering stage, the product volume shrinks and the strength is improved because the gap between the particles is greatly reduced. The advantage of powder injection molding is reflected in this: because the embryo of the product is injected by mixing the metal powder and binder uniformly according to a certain proportion, so the composition of each part of the embryo is relatively uniform, so that when sintering can ensure that the product can be isotropic contraction in all directions, which can well guarantee the shape and dimensional accuracy of the product, which is also a feature of the MIM.

With the innovation and progress of technology, material processing technology toward the direction of high-performance, low-cost, short process, near-final molding development, the emergence of a number of design, preparation, processing in one of the new preparation technology, such as metal powder injection molding technology.

Metal powder injection molding process to produce metal powder metallurgy products, it is the traditional powder metallurgy technology and plastic injection molding process combined with the development of a new near-net molding technology, i.e., metal or ceramic powder with appropriate adhesives, through the means of injection molding to achieve the purpose of molding, and finally through the degreasing and sintering to obtain powder metallurgy products. The main technical key lies in, suitable for solid-state sintering operations of fine powder, the need for good conformability, to achieve a better sintered body density, the powder has a higher density of vibration, the higher the density of the sintered parts, the complexity of the binder additives, fully mixed with the full feeder, high precision molds, fast replication of the injection molding machine, high-speed and safe and effective catalytic degreasing, the use of solid-state sintering, the application of the metal phase diagrams The material science science knowledge is used to ensure the denseness and conformability of the sintered body from the embryo to the sintered body, resulting in a high quality product.