A wireless holder system with acceleration sensors was constructed to measure radial and rotational acceleration on a rotary coordinate system. As a new application, we examined the spindle conditions of two types of machining centers, which were the same model with different specifications of maximum spindle rotation speed, and considered the machining characteristics while performing comparison with servo internal information. In addition, we performed monitoring of a ball end mill finishing process, which was difficult to diagnose with internal servo information. The results demonstrated that the proposed holder system made it feasible to monitor the phenomenon of chatter vibration due to anisotropy of rigidity in machine tools.

We proposed turn grinding that controls the grinding wheel posture according to the purpose of machining. Geometrical analysis and experimental evaluation were performed to clarify the grinding performance of turn grinding compared with cylindrical traverse grinding. When the wheel rotation axis and the workpiece rotation axis were orthogonal, the grain depth of cut and the contact length were calculated from the grain trajectory of the abrasive grain. The influence of grinding conditions was investigated. The grain depth of cut of turn grinding was smaller compared with cylindrical grinding; the larger the wheel depth of cut, the larger the difference between turn grinding and cylindrical grinding. Furthermore, experiments using a multitasking machine clarified that the dimensional accuracy and surface roughness were improved without decreasing the grinding efficiency.