Laser-beam working - using additional energy source to maintain plasma energy coupling capability during time in cycle when main laser beam is switched off

摘要

Method of working a workpiece with a laser beam consists of directing the laser beam onto the workpiece for a short time (T1) with an intensity (1b) which is above the lower level (Ic) at which a surface plasma is produced but below an upper level (Id) at which a laser beam induced detonation wave is produced. The beam is cyclically broken and replaced during the non-working stage by a second energy beam. The duration of the second beam is much longer than that of the first beam which built the plasma and has an intensity (IL2) which avoids any beam induced detonation waves. After a predetermined time (Tr) the first beam is renewed for the required time (T1). ADVANTAGE - The second energy beam ensures that the plasma is not fully extinguished and retains an energy coupling through it. This unbroken energy coupling increases the coupling rate of the energy over the working time thereby increasing the working efficiency without fear of detonation waves.