Investigation of Laser Cutting of Thin Polymethyl Methacrylate Sheets by Response Surface Methodology

Laser cutting is a precise, powerful, and low-cost tool for cutting different sheets of metals and polymers. The literature survey shows that the quality of cutting (surface roughness and kerf geometry) is a sophisticated parameter and conventional approaches cannot describe the quality of cutting for thin sheets of polymers very well. Statistical tools can help to interpret the effect of process variables. In this article, the laser cutting of Polymethyl methacrylate (PMMA) is experimentally investigated. The effect of process variables of laser cutting including the scanning speed, laser power, and laser beam diameter on the kerf width and surface roughness by Response Surface Methodology design investigated. The results revealed that increasing the laser power leads to increasing the surface roughness and decreasing the taper angle, while the kerf width at the top and bottom surface of the sheet decreases at first, then increases (for higher laser power than 90W). Also, increasing the scanning speed causes increasing surface roughness while the taper angle and the kerf width at the top and bottom surface increase at first, then it decrease. By increasing the laser beam diameter, the surface roughness will increase while the taper angle and the kerf width at the top and bottom surface decrease at first and then increase. The sophisticated effect of the main process variables and their interactions determines that finding the optimum condition of process parameters is hard and multi-objective optimization approaches are needed to find local minimum surface roughness and kerf geometry.