Effect of MQL and dry processes on the particle emission and part quality during milling of aluminum alloys

MQL and dry processes are becoming the most important issues in future manufacturing. Reducing or completely eliminate the lubricant can improve machining performances, air quality and reduce the machining costs. The coolant used in MQL should be environmentally friendly. The flow rate should be also optimized in order to enhance the machining performance and reduces the particles emission. Our research study was conducted in order to optimize the dry and the MQL processes. It has been found that the MQL process can reduce the cutting forces, friction and wear compared to the dry cutting. Chip morphology shows that the use of the coolant during MQL process embrittles the chip. However, in particular situations, the dry process can be competitive compared to the wet or the MQL processes. In this paper, an investigation study was carried out on the performance of MQL (Minimum Quantity of Lubricant) and dry high speed milling of three kinds of aluminum alloys 7075, 6061 and 2024. Four different flow rate of mist are tested during MQL machining processes. The effects of cutting speed, lubrication mode and material on the part quality were investigated. The machining performance is evaluated according cutting force, particle emission and the surface finish. Experimental results showed that the MQL milling can be interested in terms of force or surface finish but if the particle emission is considered the dry machining will be better. For the different lubrication modes at very high speeds, the results seem to converge. In this case, the dry machining should be advantageous.