The Effect of Low Power CO2 Laser Cutting Process Parameters on Polycarbonate Cut Quality Produced By Injection Molding

In the present study, the effect of gas pressure and laser beam focal plane position (FPP) on the geometry and roughness of kerf quality of the injected polycarbonate with the thickness of 3.2 mm in laser cutting by using low power continuous CO2 laser is investigated. Gas pressure and FPP were variable parameters in this research, while other processing parameters (i.e. laser power and cutting speed) are considered constant. Gas pressure experiments were carried out by varying the gas pressure from 0.5 to 3.5 bars and the FPP experiments were performed in FPP= 0 to FPP= -4mm. Kerf geometry quality (upper and lower kerf width, kerf taper, upper heat affected zone) and surface roughness of the kerf wall were also considered as the responses. Results show that gas pressure and FPP has a significant effect on the kerf quality. Increasing the gas pressure and the position of the laser beam focal point increases the upper and lower kerf width. Results also reveal that upper heat affected zone value decreases by reduction in FPP and increases the gas pressure. Increasing the gas pressure will reduce the kerf taper angle and reduction in the FPP reduces the surface roughness of the kerf wall. Observations indicated that by locating the laser spot point in the depth of the workpiece the laser cutting quality increases.