Quantification of Melt Dynamics from High-Speed Observations Within the Remote Fusion Cutting Regime by Means of Image Processing

Abstract

AbstractDuring laser keyhole welding of metal sheets, a process regime has been observed where no stable welding process sets in. Instead, material is ejected at the keyhole bottom, leading to the formation of a cutting kerf. The forces driving the melt ejection originate from the laser material interaction itself opposite to conventional fusion cutting, where an assist gas has to be used to enforce the melt ejection. As there is no need for a local application of auxiliary materials or gases, this holds the potential for a remote fusion cutting process. So far, only initial research exists concerning its occurrence and the underlying physical mechanisms are barely understood. Therefore, we use high-speed imaging of the cutting front and the melt ejection to generate insights into the melt dynamics. An evaluation approach is presented which incorporates image processing to enable the automated processing of large datasets, allowing a quantification of the observed effects and the evaluation of large-scaled studies of the melt behaviour for different parameters. The presented methodology enables the investigation of the mechanisms leading up to stable remote fusion cutting.KeywordsLaser cuttingRemote fusion cuttingImage processing