Tool-wear analysis in cryogenic machining of NiTi shape memory alloys: A comparison of tool-wear performance with dry and MQL machining

Extremely high tool-wear rate in machining of NiTi shape memory alloys (SMAs) is one of the major reasons for limiting the use of conventional machining processes on NiTi. The present study begins to address this issue by examining the effects of cryogenic cooling on tool-wear rate and progressive tool-wear by comparing the new findings from cryogenic machining with results obtained from minimum quantity lubrication (MQL) and dry machining conditions. Flank wear at the nose region, notch wear at the depth of cut boundary, and resulting machining performance criteria such as force components and surface quality of machined samples were studied. The findings from this research demonstrate that cryogenic cooling has a profound effect on controlling tool-wear rate and that the progressive tool-wear in machining of NiTi shape memory alloys can be significantly reduced by cryogenic machining.