In-line monitoring of focus shift by kerf width detection with coaxial thermal imaging during laser cutting

Nowadays, industrial laser cutting systems employ a fixed set of process parameters throughout the cut same workpiece, which results in good compromise between maximum productivity and surface quality. The are commonly by trial-and-error experiments carried out on different materials thicknesses or less frequently physical modelling. However, final quality is not constant even though kept due to degradation initial status system. One common issues local heating optical components contamination and/or high powers employed, cause shifting focus position. This can worsen cutting-edge quality, result with loss cut. Therefore, online measurement position requirement for consistent process. An empirical method used practice initially setting successively examining adjusting measure kerf width straight-line performed parameters. paper proposes an algorithm monitor yield estimated real-time during observed coaxial camera module mounted head monitors thermal interaction beam material. image processing was developed extracting from acquired images, were experimentally calibrated such that extracted value matches its measure. To understand influence kerf, experimental campaign conducted subsequently regression model fitted. monitoring computation correlation give opportunity closed-loop control shift, would eventually lead gain stability repeatability.