Investigation of Top Burr Formation in Micromilling for Surface Quality Improvement

This paper deals with the study of top burr formation mechanism in downmilling operation on Ti6Al4V. Detailed and simplified flute locus in the milling operation has been elaborated with varying uncut chip areas during the entry and exit of the flute. The mechanism shows that top burr formed in downmilling is a combination of upmilling tear material and side bulging deformed material. Furthermore, various shapes of top burr formation at different cutting parameters have been explored based on the mechanism of formation. Three types of burr formation during downmilling (serrated, longitudinal and curly burrs) were found which were the major cause of poor surface finish after milling operation. Also, the effect of feed per tooth and depth of cut on the top burr formation & surface roughness has been analyzed through statistical technique ANOVA and an optimum parameter (top burr width: feed per tooth 8 mu m, depth of cut 60 mu m and surface roughness: feed per tooth 4 mu m, depth of cut 40 mu m) has been proposed which can help to plan to design the experiment to obtain better output response.