Micro-joining of Multiple Stainless-Steel Sheets into a Mechanical Element by Low-Temperature Diffusion Process

Abstract

A new microjoining system of plasma surface activation and intelligent heat induction processes has been developed. This microjoining process consisted of two steps. Eight stainless steel-sheets each with a thickness of 0.01 mm was surface activated by argon and hydrogen plasmas for 600 s. The passivated oxide film thickness was reduced by this surface activation. In the second step, the stack of eight stainless steel-sheets was accurately hot-stamped and joined into a mechanical element. The intelligent induction heating unit was utilized to accomplish uniform heating of the whole stack up to 1073 K for 60 seconds. Concurrent with heating, the stack was hot-stamped and held by 30 MPa for 1800 seconds. The miniature products and members such as a micropump were fabricated by this microjoining process as an alternative process that enables as to lower the joining temperature, shorten the duration time and to reduce the production cost for high qualification of metallic micropumps.