Research on the Forming Mechanism of Micro-Moulds Based on Laminated Slip-Welding of Ultrathin Stainless Steel Foils

Abstract

To address the mainstream technology of UV-LIGA combined with micro-electroforming which could only fabricate micro-moulds cavity with vertical wall structure and low depth-to-width ratio, a new forming process based on femtosecond laser combined with laminated slip-welding was proposed in the paper. The forming process was achieved through experiment and it proved that the forming process could be a useful method for the process of micro-moulds with high depth-to-width ratio and complex structures. Work-pieces which were 0Cr18Ni9 stainless steel foils whose thickness was 20μm were welded by resistance welding machine and the microstructure of welding-zone was observed in detail. It was found that the welding-zone was composed of nugget zone, fusion zone and heat affected zone. Through the study of welding mechanism, the cooling rate of nugget zone was 3.99×104K/s and there was dynamic recrystallization in nugget zone. For further study, through the X-ray diffraction (XRD) test, it was found there were no chromium carbide and iron-copper eutectic alloy in nugget zone.