Application of Acoustic Emission on Monitoring of Chip Loading and Surface Roughness for Grinding

Grinding processing is an important part of precision machining. Grinding technology provided fine precision and surface roughness. Grinding is used abrasive grain to removal material; however, chip loading clogged the pores of grinding wheel and edge of abrasive to affect ability of grinding, so immediate dress is necessary to maintain fine surface roughness of workpiece. The purpose of this study was to monitor the state of grinding wheel by acoustic energy of changed structure from grinding materials, detecting the state of chip loading of wheel surface and pore to control the surface roughness of workpiece. The method used in this paper was to detect trend of chip loading fill and drop by magnitude of spectrum, to reflect state of chip loading and predict surface roughness, this method provided to avoid the burns and monitor the quality for workpiece. This study investigated the state of chip loading with grinding parameter to predict surface roughness of workpiece. The results of the experiment indicated that the chip loading status divided into three parts; the first part was magnitude rise area that was chip loading filled pores in the wheel until close to the plane, workpiece maintain good surface roughness; the second part was magnitude fall area that was chip loading dropping first, this phenomenon made surface of grinding wheel rugged; the third part was low magnitude area that was chip loading continually dropping deteriorate surface of wheel and affecting the roughness of workpiece surface. The experiment verified grinding parameters change chip loading region and affect the workpiece surface roughness. The findings of the research have led to the conclusion that acoustic emission signal was transformed by Fast Fourier Transform, this method can be determined area of chip loading and situation of grinding wheel loading in order to achieve to monitor grinding. When the magnitude of spectrum reach the low range, grinding wheel is going to dress. This method has been successfully controlling the quality of the surface roughness.