Fabrication of 316-L stainless steel micro components using encapsulating soft mould and isopressing technique

Abstract

This paper presents in detail a new method to fabricate free standing 316-L stainless steel micro components using high solid loading stainless steel semi solid paste encapsulated into soft mould (PDMS) and pressed using hydrostatic pressure. The process is divided into five parts: (i) production of SU-8 master moulds and their negative replicas from soft moulds, (ii) preparation of stainless steel semi solid paste with high solid loading and filling the soft mould insert, (iii) the soft mould is sealed well and put under hydrostatic pressure, (iv) after the pressure is released the soft mould seal is removed and the paste is left to dry, (v) the green parts are obtained, de-bound, and sintered in vacuum at 1350 °C. The effect of the applied hydrostatic pressure on both the green and sintered densities as well as the linear shrinkage of the micro components was investigated in detail and compared with the pressure-less filling method. It is found that both the green and sintered densities increase while the linear shrinkage decreases with the increase of applied hydrostatic pressure. The maximum sintered density and its corresponding linear shrinkage were found to be 98.6% and 13%, respectively.