DUAL WAVELENGTH LASER CUTTER

THE ABILITY TO CUT VERY SMALL AND VERY PRECISE HOLES HAS BEEN DEVELOPED, TO SOME DEGREE, BY ANISIMOV, ET AL(1). THE TECHNIQUE USED WAS THE COMBINATION OF TWO OR MORE LASERS IN ORDER TO DRILL VERY CLEAN HOLES. THAT IS, HOLES THAT HAVE VIRTUALLY NO KERF AND MAINTAIN DIMENSIONALITY THROUGH THE THICKNESS OF THE MATERIAL. IN THE SAME VEIN, WHAT IS PROPOSED IN THIS PROJECT WILL BE THE USE OF A CONTINUOUS WAVE INFRARED CO(2) LASER IN ORDER TO HEAT THE AREA THAT IS TO BE DRILLED AND THE COMBINATION OF A 100 HZ VISIBLE DYE LASER TO REMOVE THE METAL FROM THE HOLE. THE CO(2) LASER TAKES AWAY THE RADIAL COMPONENT OF THERMAL DIFFUSION SO THAT THE VISIBLE LASER ENERGY IS NOT DISSIPATED IN THE RADIAL COMPONENT. ALL THE ENERGY OF THE PULSE LASER IS ABSORBED DIRECTLY IN THE AREA THAT IS TO BE DRILLED. BY USING THE PULSED TECHNIQUE, MATERIAL CAN BE REMOVED MORE RAPIDLY WITH EACH PULSE. THE PERIOD OF TIME FOR THE CO(2) LASER TO IRRADIATE THE SURFACE WILL VARY FROM MATERIAL TO MATERIAL INASMUCH AS THE THERMAL DIFFUSION OF MANY OF THE HIGH TEMPERATURE ALLOYS IS SUBSTANTIALLY LOWER THAN THOSE OF THE MORE CONVENTIONAL METALS. AT THE SAME TIME, ONE WOULD WANT TO DRILL THE HOLES WITHOUT DISTRESSING THE TEMPER OF THE SURROUNDING METAL. THE TEMPERATURE RISE CREATED BY THE THERMAL FIELD LASER MUST BE SET AT A LEVEL THAT WILL ENHANCE THE PULSED LASER EFFECTIVENESS AND NOT DISTURB THE CRYSTAL STRUCTURE OF THE SURROUNDING MATERIAL.