The Taguchi method for determining CO₂ laser cut quality

The rapid growth in the application of lasers as a cutting tool has generated considerable interest in the quality of the cut edges produced. Consequently, the present study is conducted to assess cut edge quality, by defining the measurable variables, using international standards for thermal cutting. The measurable variables defining the cut edges may include waviness and flatness. Cutting speed, oxygen pressure, and workpiece thickness are considered as cutting parameters, therefore the Taguchi method is used to classify the relevant parameters. The study is extended to include the detection of light emission from the surface plasma. This makes it possible to monitor temporal behavior of the surface plasma, which in turn gives information about the formation of striations. Scanning electron microscope microphotography is conducted to examine the resulting cut surfaces. It is found that the cut quality is mainly affected by the oxygen gas pressure and cutting speed. However, flatness depends significantly on the thickness. Microcracks appear on the cut edge surfaces due to rapid solidification of the molten oxide layer formed on the surface.