Experimental research on micro-deep drawing processes of pure gold thin sheet using DLC-coated female die

Micro-forming has been considered as an alternative for micro-fabrication method of micro-parts for its massive production characters. With pure gold thin sheet, the manufacture of micro-parts, e.g., micro-cup is still a delicate and challenging task and has received less attention. Since there are size effects of friction when a liquid lubricant is applied, the forming process becomes sensitive to the friction for the small strength of pure gold shin sheet, and the traditional deep drawing process cannot easily adapt to these kinds of micro-parts. This study presents the results of research conducted on micro-cup deep drawing process with pure gold thin sheet using diamond-like carbon film and polyethylene film to reduce the friction. In particular, the effect of lubrication condition on punch load, surface profile, reduction of thickness, and accuracy of inner diameter are investigated and discussed. Experimental results show that the diamond-like carbon-coated female die leads to lower punch load, high surface quality, uniform thickness of sheet, and high diameter accuracy. The diamond-like carbon film presents excellent wear-resistance properties under high contact pressure and large plastic deformation of thin sheet. The results indicate that micro-forming using diamond-like carbon-coated female die shows potentiality to be feasible alternative to micro-parts of pure gold thin sheet.