High Density RF-DC Plasma Nitriding under Optimized Conditions by Plasma-Diagnosis

Fabrication of Punch and Die Using Plasma-Assisted 3D Printing Technology for Piercing Sheet Metals

A pair of punch and die was often fabricated using subtractive manufacturing processes such as milling and other machining processes. However, additive manufacturing could be used to perform the same processes. This study explored this possibility. In particular, this study fabricated a pair of T-shaped punch and die made of AISI316L austenitic stainless steel using an additive manufacturing process called plasma-assisted 3D printing. Accordingly, T-shaped negative and positive 2D patterns were screen-printed onto the mirror-polished surfaces of the substrates made of AISI316L austenitic stainless steel. The printed film worked like a mask to prevent the printed substrate surfaces from nitriding. In order to form a thick nitrided layer, the unprinted substrate surfaces were selectively nitrided at 673 K for 14.4 ks. The un-nitrided segments of the substrates were uniformly removed by sand-blasting that involved shooting silica particles on the substrate’s surfaces. As a result, the substrates printed with negative and positive T-shaped patterns were transformed into the punch head and die cavity. In order to see the efficacy of the fabricated punch and die pair, this pair was used for piercing the electrical steel sheets under a controlled clearance. Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX) was used to measure surface topography after piercing. In addition, SEM and a 3D profilometer were used to measure the punch and die profiles after piercing. The abovementioned measurement results showed that the fabricated punch and die exhibited highly accurate piercing behavior. Thus, the plasma-assisted 3D printing was useful for punch and die fabrication.