Tool Wear Behaviour of Micro-Tools in High Speed CNC Machining

Cutting tool life is one of the most important economic considerations in metal cutting. In roughing operations the various tool angles, cutting speeds and feed rates are usually chosen in order to achieve economic tool life. In micro-machining, unpredictable tool life and premature tool failure are major problems. Furthermore, it is impractical to determine the tool life of micro end-mills with a diameter in the region of 1mm using the standard criterion as given in the ISO 8688-2:1989 ‘Tool Life Testing in Milling’. In this investigation, the tool life criteria of micro tools were evaluated for the machining of H13 tool steels and Titanium Alloy Ti6A14V. The correlation between tool wear and the cutting forces were also studied. Inspections of the tool edges by Scanning Electron Microscopy (SEM) revealed the progression of tool wear, and in several other cases, sudden tool breakages were also observed.