Grinding is an abrasive machining process which corrects nonconformities of workpieces. The usage of cutting fluids thus become necessary, since it assures better finishing due to its cooling capacity, which hinders thermal damages, and lubrication. The large scale application of cutting fluids has driven, in the last decades, a great number of researches on new cooling-lubrication methods, aiming to attend strict requirements concerning the environmental protection, through minimization of toxic wastes due to fluid disposal. Therefore, solutions must be sought in order to mantain the same quality of flood coolant aplication (cooling, lubrication, wheel cleaning). An alternative to conventional cooling-lubrication is minimum quantity lubrication (MQL), which uses a spray of oil droplets at low flow rate in a compressed air jet, thus minimizing disposal hazards. However, in many studies, the phenomenon of wheel clogging was noticed, since MQL does not provide efficient cleaning of the cutting surface, harming results such as surface roughness, diametric wheel wear and roundness errors, when compared to flood coolant application. The material to be ground (VP 50 steel) is widely used in injection molds. The vitrified bond silicon carbide wheel is a conventional abrasive, which posesses medium-to-high hardness and great friability, indicated for grinding hard materials with low tenacity (hard metals, cast irons, non-ferrous and non-metallic materials). This type of abrasive is harder than aluminum oxide, thus being more brittle. The results will be obtained through the analysis of the following output variables: tangential cutting force, surface roughness, acoustic emission signals (RMS), G ratio (volume of material worn / volume of wheel worn), along with metallographic images and microhardness measurements.
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