Comparison of milling forces and vibrations in machining additively manufactured A205 under dry and lubricated conditions

A205 aluminum is a promising new additively manufacturable aluminum alloy. Prior research showed that such A205 aluminum had poor machinability under single-point turning conditions, such as poor surface finish and high-frequency vibrations, as compared to its cast counterpart. This research sought to confirm these results under multi-point milling and determine the effects of two different lubrication methods (flood and MQL) on machining A205 aluminum. In addition to the comparisons in surface finish, force and vibration magnitude, a spectrogram analysis was employed to compare time-series cutting dynamics. The results found that lubrication reduced the average surface roughness up to 80% (average of 3.5 vs. 0.7 µm), cutting forces up to 30% (average of 26 vs. 18 N) and cutting vibrations up to 50% (average of 40.8 vs. 20.3 m/s2) and resulted in more stable, fewer and lower vibrations over time. However, the differences between flood and MQL were not differentiable with any statistical significance for the feeds and speeds chosen. The results suggested the necessity of applying lubrication in A205 machining, but the selection of flood or MQL was not critical.