Investigation of the effect to processing quality of water jet guided laser system

Laser technology has expanded its area of utilization in several sectors and gaining increased importance each year. This technology managed to take precedence over its alternatives in the areas whereby it is utilized. A great deal of research and study are performed to improve the quality of material cutting with laser technology. One of the most important stages in the laser cutting process is the effective transmission and focusing to the correct distance on the material. Changes in focal point due to varying material thicknesses cause non-favorable effect on the quality of work-piece and loss of time in manufacturing. Although three axis laser cutting machines are manufactured, this matter can not be resolved entirely. In this study, focal depth of the laser beam has been extended by means of guiding it thorough a water jet. For this purpose, a testing apparatus has been set up. A water-jet head is designed and the laser beam has been focused into water-jet by this head. Marking processes have been performed by laser shots on the surface of polymethylmethacrylate material from different focal distances. Then, the marks made by laser beam has been measured and compared with that of traditional dry laser. Three different focal distances are used for both methods. Focal length values used in the conventional method are 63,5 mm, 65,5 mm and 67,5 mm. Focal distance used for the water jet guided laser method are 68 mm, 70 mm and 72 mm. Improvements of %5-70 were achieved in the size, depth and roundness of marks on the workpiece by using water jet guided laser.