Efeitos da variação da granulometria de rebolos de cBN e parâmetros de corte sobre a qualidade da peça na retificação cilíndrica interna do aço 18CrNi8

Abstract

Precision internal cylindrical grinding operations is usually the last step in a manufacturing process that involves machining processes. At this stage, the parts already have high added value, making their disposal due to manufacturing errors even more costly for companies. Thus, the tools adopted in these operations must be used with properties and cutting parameters that favor the best cost/benefit ratio of the grinding wheel in order to maintain or improve the quality standards of the ground parts. In this context, this research aims to analyze the effects of the particle size of vitrified cBN grinding wheels (360 and 400 specification) and the variation of the workpiece rotation parameters workpiece rotation (nw = 1400, 1600 e 1800 rpm) and axial feed rate of the tool (Vfa = 600, 800 e 1000 mm/min) in the internal cylindrical grinding of DIN 18CrNi8 steel on the final quality of the part. Aspects such as the dimensional quality of the diameter, surface roughness and geometric errors of circularity, straightness and parallelism were considered, in addition to the observation of grinding wheel wear and grinding power. In general rules, the grinding wheel with a 400 grain size specification presented better results for the process outputs compared to the 360 one. This was more evident in the more severe test conditions (nw = 1800 rpm e Vfa = 1000 mm/min).