Dimensional Accuracy of Sintered Machine Parts (1st Report)

Effects of Degree of Mixing of Fe and Cu Powders

Abstract

In the mixing process, inhomogeneity in the mixed powder produces the dimensional variation among specimens and bending in a specimen. In this study, the degree of mixing is adopted as the dispersion of the mixing ratio in the mixed powder. The influences of the mixing ratio, the lubricant and the mixing apparatus on the degree of mixing of Cu and Fe powders were studied, and the adhesion of Cu to Fe particles was also studied by using the wet magnetic separation method.
The factors affecting the dimensional variation of sintered machine parts with the mixing process are the mixing ratio, the amount of sample and the state of the surface of particle (shape, etc.). They make the dimensional accuracy worse about 0.47-0.016 percents of size of parts.
The adhesion of Cu to Fe particles is also influenced by the shape of powder, the lubricant and the mixing apparatus. The amount of adhesion becomes larger in the irregular shape of particles and in using the Lodige mixer.