Application of the auxiliary wheel cleaning jet in the plunge cylindrical grinding with Minimum Quantity Lubrication technique under various flow rates

Minimum Quantity Lubrication is an alternative technique to conventional techniques that are related to environmental sustainability and economic benefits. This technique promotes the substantial reduction of the amount of coolant employed in machining processes, representing a mitigation of risks to people's health that are involved with the process. On the other hand, it has been reported in the literature that some problems of using the Minimum Quantity Lubrication technique can impair the grinding efficiency. One of these problems is associated with wheel clogging phenomenon, which is caused by inefficient chip removal from the cutting zone as well as from mixture of metal dust and oil accumulated on the wheel surface during grinding. If chips lodge inside the pores of the grinding wheel as machining progresses, they will adversely affect dimensional and geometric quality of final product. Also, this will require more frequent dressing. A solution for this problem can be an effective cleaning system of the abrasive wheel during grinding with the traditional Minimum Quantity Lubrication technique Assisted with Wheel Cleaning Jet. In this context and aiming to explore the various potential health, environmental and economic benefits that have been widely reported in the literature about the use of Minimum Quantity Lubrication technique in grinding, this study presents an application of the Minimum Quantity Lubrication technique at flow rates (30, 60 and 120 mL/h) and assisted with wheel cleaning jet (Minimum Quantity Lubrication + Assisted with Wheel Cleaning Jet) in plunge grinding of a hardened steel with an aluminum oxide wheel. Experiments were also carried out with traditional Minimum Quantity Lubrication (without wheel cleaning) and with the conventional coolant techniques for comparison. The output variables were geometrical errors (surface roughness and roundness) of the workpiece, diametric wheel wear, acoustic emission, vibration and tangential cutting force. Results showed that Minimum Quantity Lubrication + Assisted with Wheel Cleaning Jet (with wheel cleaning jet) not only outperformed the traditional Minimum Quantity Lubrication technique in all the parameters analyzed, but in some cases it proved to be compatible with the conventional coolant technique under the conditions investigated. Also, most of values of the output parameters tested decreased with increase in flow rate.