Investigation of burr formation and surface integrity in micro-milling of aluminum alloy LF21 slot

Due to the nature of LF21 aluminum alloy material, it is difficult to process and easily prone to plastic deformation; hence, micro-milling process is prone to produce larger burrs and rougher surface. Currently, there are fewer investigations on LF21 slot micro-milling. So, this article uses a combination of finite element simulation and experimentation to analyze the effects of different cutting parameters on the LF21 slot exit, top burr size, and the surface quality of the bottom of the slot. The results of the investigation show that the top burr and exit burr sizes as well as the surface roughness at the bottom of the groove show a monotonically decreasing trend as the spindle speed increases, especially on the up-milling side where the burr size is significantly smaller than that on the down-milling side. Variation in feed rate plays a pivotal role in burr size and groove bottom roughness. The smallest burr size, along with the best surface quality, is achieved when the feed per tooth is close to the tool edge radius. Furthermore, as the cutting depth increases, both the burr size and surface roughness also increase. This effect becomes particularly pronounced at larger cutting depths, where surface valleys are markedly higher and grooves become significantly deeper. The results of this investigation are instructive for practical micro-milling of aluminum alloy LF21, which is important for improving machining efficiency.