Investigation of burr formation and tool wear in micromilling operation of duplex stainless steel

Despite progress in the study of micro-machining processes, there is still no consensus on the effect of cutting conditions or standardization of procedures for comparison of the results, due to the typical difficulties of micro-scale processes. In this context, this work has as main objective the investigation of tool wear and burr formation in micro milling operation of UNS S32205 duplex stainless steel. Experimental tests were carried out micro machining slots using a CNC micro mill machine tool, with a maximum spindle speed of 60,000 rpm. The performance of cemented carbide microtools of two different diameters (200 mu m and 400 mu m) was analyzed. The results showed that the tools with a diameter of 200 mu m presented an excellent performance concerning the machined length. However, increased cutting speed led to excessive wear and high burrs. The use of cutting fluid attenuated the wear and the height of the burrs. Finally, the best machinability was obtained using tools of bigger diameter (400 mu m). Lower wear and smaller burrs were obtained compared to tools of smaller diameter (200 mu m).