Development of a sensor integrated "intelligent" grinding wheel for in-process monitoring of ceramic grinding
A sensor integrated “intelligent” diamond grinding wheel was designed and developed for in-process monitoring of ceramic grinding processes. The system is capable of monitoring normal force, acoustic emission, gap elimination and wheel rounding process in real-time. The prototype wheel consisted of an aluminum core integrated with piezo-ceramic sensors and diamond abrasive segments bonded on the periphery. A DSP based telemetric data acquisition was employed to acquire, process and transmit data from the rotating wheel to a remote receiver. Software was developed for data interception, processing and presentation of process information.
The mechanical design of the “intelligent” grinding wheel was evaluated both by numerical simulations and static experiments. Prior to system integration, experiments were conducted on each sub-component of the system to ascertain its performance and mechanical integrity. The capabilities of the “intelligent” grinding wheel was verified through grinding and wheel preparation experiments. The DSP was programmed to implement application specific algorithms for process monitoring. Wheel roundness during truing was monitored by comparing the outputs from all eleven force sensors located on the outer periphery of the wheel. Normal force monitored by the “intelligent” grinding wheel showed a close match with that measured by a commercial dynamometer. Furthermore, it was shown that acoustic emission signal monitored by this system can identify Wheel-workpiece contact, thereby serving as useful gap elimination tool. In addition, it was demonstrated that the acoustic signal is sensitive to grinding parameters and can provide corroborative evidence to normal force measurements. Finally, the “intelligent” grinding wheel was used to study contact length and normal force distribution in the grinding zone.
The prototype wheel used diamond abrasives for grinding of ceramic components. This same approach can also be applied to CBN wheels for grinding of ferrous and nickel based alloys. The results of this investigation provide the scientific and technological basis for commercial development of a new generation of monitoring systems for machining.