Effect of laser cutting conditions on the cutting front profile observed by X-ray transmission in real time

Abstract

In laser cutting, industrial practitioners have historically demanded higher cutting speeds and better quality cuts. Thus, there has been significant interest in the elucidation of related processing phenomena. The cutting quality is commonly affected by the ejection behavior of the generated melt, which might be influenced by the profile of the laser cutting front. Therefore, it is desirable to directly observe the cutting front in real time; however, this cannot be easily achieved practically. In our previous work, we applied real-time observation using an X-ray transmission system to laser cutting fronts, thus enabling observation of the profile of the cutting front and the ejection behavior of the melt simultaneously. In this study, we quantitatively evaluate the cutting front profile observed fluoroscopically in real time using an X-ray transmission system and discuss the relationship between the profile and ejection behavior of the melt. In addition, we investigated the conditions for achieving a sound cut (dross-free cut). We directly confirmed that dross-free cutting occurs when the cutting front profile and ejection angle of the melt are approximately perpendicular to the surface of the test piece.