ABSTRACT
Grinding is a machining process by abrasion dedicated to obtain workpieces with low roughness and dimensional accuracy. In this process, it is indispensable to ensure superficial quality of the machined workpiece, the lubricant and cooling method provided by the action of the cutting fluid. However, the use of such fluid generates high cost of disposal, risks to the environment and to the machine operator's health. The main goal of this work is the study of methods that minimize such disadvantages through the optimization of the application of the cutting fluid (optimized method) or through the reduction of the fluid consumption (MQL method). The proposed methods are evaluated specifically on the cylindrical grinding of the ABNT 52100 steel grade, widely used in the manufacture of bearings by utilizing conventional silicon carbide grinding wheel with resin binder. The experiments were carried out with three different feed rates: 0.25, 0.5 and 0.75mm/min, that resulted in the following material removal rates, respectively, 0,72, 1,44 and 2,16 mm³/mm.s. The analysis of the results was made through the evaluation of the grinding process's outputs, such as roughness, grinding wheel wear, G ratio, micro-hardness and micro-structural. Good results of roughness were recorded for all of the methods, however, the results for the grinding wheel wear and the likely damages to the workpieces increase as the cooling capacity of the lubricant and cooling method decreases due to the reactivity of the silicon carbide to the iron in high temperatures. Lower cutting efforts were obtained after machining with the MQL cooling technique consequently demanding lesser machining power. However, in general, the conventional lubri-cooling method, provides better results.
Keywords:
Cylindrical grinding machining; MQL; silicon carbide grinding wheel; optimized method; conventional coolant method
