| Description |
In order to enable sustainable manufacturing, the indiscriminate use of cutting fluids in modern machining has to be tackled, given its environmental and economic impacts. A possible solution is the recent entrance of dry and near dry minimal quantity cooling and lubrication (MQC/L) machining. In order to evaluate the effectiveness and performance of MQC/L, however, further studies need to be done. The three major functions of cutting fluids are to perform cooling, lubrication, and chip removal from the cutting zone. The main objective of this work is to understand how the tribological aspects (cutting forces, chip flow, tool-chip contact area), chip morphology, and surface roughness and surface integrity (residual stresses) are influenced by i) the application of different cutting fluid combinations in minimal quantities ii) the direction of application of the cutting fluid in the facing of AISI 1045 steel using an uncoated flat-faced carbide tool. A Minimal Quantity Cutting Fluid (MQCF) dispensing system was tested and implemented to evaluate the effects of differing fluid dispensing rates and target directions. It was found that the effects of targeted cutting fluid combinations on the tribological aspects were significant when compared to dry machining, although the variation in the tribological aspects was marginal amongst the different cutting fluid combinations. In contrast, directing the coolant on the flank face of the tool revealed some interesting results. Compressive residual stresses were observed when coolant was directed to the tool flank face as opposed to other cases, which generated tensile residual stresses in the machined subsurface. This suggests that localized and carefully chosen cutting fluid target direction and combination can enhance product performance by enhancing machining performance and surface integrity. In summary, this thesis presents the significance of targeted minimal cutting fluid application in relation to machining performance (especially surface integrity) under the given cutting conditions and provides several recommendations for future work. |
