Patent DE-102009038590-A1 (DE)
Title: Method for ablating, joining, penetrating or surface treating workpieces with laser radiation, comprises moving focused laser radiation on working path relative to workpiece, where the relative motion is guided with varying velocities
Inventor: SCHNEIDER FRANK
IPC: B23K26/06
Filed: 2009-08-26
Abstract: The method for ablating, joining, penetrating or surface treating materials/workpieces with laser radiation, comprises moving the focused laser radiation on working path relative to the workpiece, where the relative motion is guided with varying velocities during the processing and a process parameter for a velocity or velocity region (G1, G2) is modulated. The modulation is adjusted in frequency, duty factor, amplitude and/or modulation pattern depending on the velocity of the working path, and the actualization of the parameter is carried out before the termination of the modulation period. The method for ablating, joining, penetrating or surface treating materials/workpieces with laser radiation, comprises moving the focused laser radiation on working path relative to the workpiece, where the relative motion is guided with varying velocities during the processing and a process parameter for a velocity or velocity region (G1, G2) is modulated. The modulation is adjusted in frequency, duty factor, amplitude and/or modulation pattern depending on the velocity of the working path, and the actualization of the modulation parameter is carried out before the termination of the modulation period, which is defined by its periodical repeating change of one or more process parameters. The determination of the actualization of modulation parameter is carried out by evaluating the actual first velocity of the relative movement between laser radiation and workpiece during a modulation period and a decision is made based on the determination that continues the current modulation period when the determined actual parameters are only valid or interrupted and replaced by a new modulation period depending on the actual velocity. For determining the modulation parameter, a predictive calculation of working path is carried out and the future velocity of the decision is carried out based on the calculation for continuing or interrupting the present modulation period and replacing with a new modulation period with different parameter. After discontinuing a modulation period, the starting of a new modulation period is carried out with different parameter that does not depend on the function of the velocity of modulation parameter and depends on a further parameter. The time of termination in the present modulation period is used as the further parameter. A high phase corresponding to the new cycle direction is continued and the modulation parameters pass into the new cycle. In a deceleration phase, the high phase corresponding to the new cycle direction is continued and the modulation parameters pass into the new cycle. In the deceleration phase, the high phase corresponding to the new cycle direction is discontinued before the termination of the old modulation parameter after the regular end so that the method is carried out without excess power. In a low-phase-modulation, the low phase in the new cycle direction is continued and the modulation parameters pass into the new cycle. Under discontinuation of the modulation period, the starting of the new modulation period is variably carried out in which the phase shift, the amplitude and/or the modulation pattern of the new modulation phase depend not only on the velocity but also on the previous modulation period. The phase shift is selected depending on the termination point of the actualized modulation pattern.