Investigation on surface quality and burr generation of high aspect ratio (HAR) micro-milled grooves

With a widespread application of micro machinery, high-quality surface demand of high aspect ratio (HAR) micro-grooves is increasing gradually. However, problems of imperfect inside-wall surface quality and massive burrs are particularly prominent in the generation process of HAR micro-grooves with the large length-diameter ratio micro-end mills. In this paper, a preliminary research on surface quality and burr generation mechanism is conducted to achieve the desired HAR micro-grooves. The top-burr generation rule of HAR grooves is discussed by establishing a FE model. The effects of cutting fluids and the wear of micro-milling tools on surface quality and micro-burr generation were analyzed. Results have shown that the burr generation and surface quality were strongly dependent on the tool wear and the groove depth. As the cutting cycles increased, the top-burr dimensions kept level with the variation in the edge-radius. Furthermore, the water-free alcohol based lubrication was demonstrated to play a positive role in improving surface quality and reducing burr generation. Finally, a desired HAR micro-groove with a nanometer level areal surface roughness (S-a = 77.4 nm) was obtained under the optimized conditions.