Cnc Machine Operation Status Monitoring Techniques

It is well-known that machining efficiency doesn't depend on the machine power and the load which machine can bear, but depends on the condition in which self-excited vibration appears. Because self-excited vibration not only cause the instability of cutting process which will reduce the machining quality, sometime it will lead the bad surface quality of machined part and maybe interrupt the cutting process. The operators have to reduce the cutting parameters in order to guarantee essential machining quality. As a result, the potential of machine productivity can not be exerted sufficiently. Therefore it is important to carry out the research on machining stability. Based on former researchers, instability of CNC turning process was wildly investigated in theoretical and practical aspects.First, this dissertation select the cantilever beam as the subject, in theoretical research, natural modes of vibration are simulated, in addition, vibration of beam of uniform strength is tested through pulse excited method.Secondly, dynamic parameters influences on the relations of stability limited width and its correspond spindle speed are simulated, furthermore, cutting stiffness coefficient is tested through dynamic machining.Finally, changes of chatter signals are confirmed in frequency domain. When no chatter occurs, vibration signals are characteristics of wide-band frequency, however, vibration signals are characteristics of narrow-band frequency while chatter occurs.This dissertation has practical value for improving machine efficiency as well as eliminating condition deviating stability due to improper use in CNC machine tool diagnosis technology.