A Study Of The Algorithm For Timely Control Of Laser Marking Power

In the laser processing, laser marking has been applied to many fields, the demand of marker's precision is also increasing. In this thesis, the algorithm and realizing method of programming for timely control of laser power is presented.Characteristics of galvanometer and some kinds of marking error such as error of pline start and end delay,off vector delay and interseg delay are analyzed in this thesis. Although errors mentioned above can be corrected by setting delay time, overmark still appears at the corner between two connected polylines. In order to timely control of laser power, a parameter-matching computer-controlling model is established to obtain constant accumulative energy in the stuff. According to the analysis of the model, the proportional relationship between laser power and scanning velocity is the necessary qualification to get good quality of marking . Two imaginable situations must be considered: the hardware system has or not have the mechanism of velocity signal feedback. In the feedback system, generally, we only get the angular velocity of galvanometer, a transform method is given in the thesis which can be used to transform angular velocity into scan velocity. In the system without velocity signal, it is most important to make sure the segments at the marking polyline where the scan velocity is changing. The number of points and corresponding velocity in speedup/ speed-down segments can be obtained through the analysis in this thesis.At last, the performance of the laser controlling system is inspected by the theory analysis, and the distributing of energy on the marking polyline is simulated using Matlab software. The results show that the algorithm can solve the overmark problem quite well.