Process control using capillary depth measurement

One important characteristics of laser beam welding is the penetration depth. Traditionally, it is determined by time-consuming and destructive cross-sectioning, but an online monitoring and eventually control system is desired. The measurement of the capillary depth in deep-penetration laser welding by optical coherence tomography (OCT), an interferometry measuring method, has been shown to be a sensing principle that allows an online in-situ measurement. It works in a wide range of industrial applications and delivers accurate data.In this paper we investigate the capability of the method and determine its restrictions.One important characteristics of laser beam welding is the penetration depth. Traditionally, it is determined by time-consuming and destructive cross-sectioning, but an online monitoring and eventually control system is desired. The measurement of the capillary depth in deep-penetration laser welding by optical coherence tomography (OCT), an interferometry measuring method, has been shown to be a sensing principle that allows an online in-situ measurement. It works in a wide range of industrial applications and delivers accurate data.In this paper we investigate the capability of the method and determine its restrictions.