In order to make qualified size, the repression process of powder metallurgical parts is called finishing shaping, and it is also called powder metallurgical shaping. In this process, the factors affecting the dimensional accuracy of parts are: radial and longitudinal density distribution of parts, parts material strength, structure of shaping die, etc.

In powder forming, the friction between powder particles, and the friction between powder particles and mould wall hinders the filling of negative cavity and affects the uniformity of density distribution. If the density distribution of compact is not uniform, great stress will be caused during sintering, which will cause uneven shrinkage, distortion and even crack of parts.

Powder metallurgy shaping is to compress the sintered parts in the die again, so as to obtain the correct size and shape. Sintering process will change parts size and shape. In order to rectify the size and shape, it is necessary to put the sintered parts into the cylinder again for shaping. Finished powder metallurgical parts will be more regular, dimensional tolerance will be better, and surface finish will be improved.