Fabrication of micro metal parts by forging process combined with powder pressing

Abstract

Abstract This study proposes a novel metal forming method based on the forging process combined with powder pressing to make micro metal parts in one operation. The method, which uses dies to simultaneously compress a solid metal billet and metal powders, is able to produce metal parts with solid and porous microstructures. In this study, a cylindrical copper billet with 1 mm diameter was first fitted on the one end inside the die cavity filled with copper powders. By conducting the proposed process, the end of the billet was forged and combined with the compacted powders to form a micro copper part with a T-shaped head of 2 mm diameter. To investigate the effects of powder shape and temperature on the proposed method, dendritic and spherical copper powders were used on two different forming conditions which were in atmosphere at room temperature and in vacuum at 400°C. Some of the parts produced at room temperature were further treated by sintering in vacuum at 800°C. The results showed that the deformed and bulged end of the solid billet surrounding by the compacted powders have been clearly observed on the micrographs of the fabricated parts from all tested conditions. For the parts treated by the sintering process, the relative densities of the dendritic and spherical copper powders were estimated to be 79.5% and 86.7%, respectively, which were lower than the values of the parts produced at room temperature and 400°C. The results demonstrated that the proposed method successfully fabricated the micro copper part with solid and porous microstructures.