Technology Research, Based On The Grinding Acoustic Emission Monitoring

Acoustic emission (AE) is a kind of ubiquitous physical phenomenon in the solid materials. As a new type of nondestructive testing technology, AE has been widely used in many fields, such as mechanical processing. The grinding process is a rather complicated process, where the grinding area contains plenty of AE signal sources which reflect the changes of grinding conditions from different aspects. Because AE testing has a high sensibility and the monitoring process can be accomplished without stopping the machine, it is very appropriate to use AE testing for on-line monitoring in grinding processing. Based on AE technology, a grinding monitoring system is developed in this paper, and related grinding monitoring experiments are made in order to investigate the applications of AE in grinding monitoring. The main research contents of this paper are as follows:The formation mechanism of AE signal is analyzed necessarily and two methods for AE signal processing --- parameter analytical method and waveform analytical method --- are introduced, which builds a theory foundation for the following studies.The integral design of the AE-based grinding monitoring system is performed, and the main elements along with the principle of work of the system are elaborated. The hardware design of the system is performed according to the needs the system must meet.On the basis of the integral design of the grinding monitoring system, the software function modules of the AE-based grinding monitoring system are designed and developed one by one via LabVIEW and VC++, including signal gathering function module, signal analyzing and processing function module, communicating function module, waveform showing and data storing function module, etc.Related practical grinding monitoring experiments are performed on a reconstructed NC grinding machine. The feasibility of the grinding contact is experimentalized. The thresholds of the AE characteristic parameters for grinding contact monitoring are identified through gathering the changing AE signal which is produced before and after the grinding wheel contacts workpiece. It has been proved by practical grinding experiment that using AE signal as a grinding switch is feasible. The grinding experiments for the grinding wheel dull are carried out. The effect of the grinding parameters on the process of the grinding wheel dull is analyzed. The thresholds of AE ring-down counts and RMS used for the wheel dull monitoring are identified according to the experiments results. Finally, it has been proved by practical grinding experiment that it is feasible to use grinding AE signal for monitoring the conditions of the grinding wheel dull.