For a machine tool, the spindle is an essential element in the machining process, so sporadic repairs to or replacement of the spindle can directly affect the machine tool user's productivity. If slight abnormalities could be detected before they caused major damage to the spindle, both the machine tool user and the machine tool manufacturer would beneft: the user from reduced downtime; the manufacturer from reduced need to provide servicing. In the present study, accordingly, the power consumption of the motor that turns the spindle was evaluated by using the error root mean square fbr the purpose of developing a system that could discriminate and diagnose the condition of the spindle. This time, data for 28 spindles that were shipped following a previous report entitled 'Development Of Spindle life prediction system using MT system' was newly analyzed, S/N ratios and distances were recalculated for a total of 45 spindles, and overall trends were investigated by use of a correlation matrix. As a result, it became clear that the S/N ratio and distance were distributed differently for different spindle specifications, and that it might be possible to detect abnormal conditions more accurately by use of factor analysis and the correlation matrix instead of just using distances.
The present project began as an effort to optimize the production conditions for obtaining desired magnetic properties in a magnet used for contactless position sensing in automobile components. The magnet was developed in-house through two main processes:adesign process, in which the design department determined the shape of the magnet;and a process in which the production technology development department determined the method by which to manufacture the magnet. These processes were optimized individually in the design department and production technology development department, by use of parameter design, but that failed to produce the desired magnetic properties. The desired magnetic properties were finally obtained by feeding data obtained from experiments carried out in the production technology development department to optimize the manufacturing method back to the design department and redesigning the shape of the magnet. This accordingly became a case study in the importance of macro quality engineering, by showing that overall optimization is not achieved just by optimization of subsystems. This report describes the steps that led to final optimization, focusing on the results of parameter design in the magnetization process, which is a subsystem of the production process.