To date visual quality control of billet surface is usually done by operators. Hertwich has developed a billet surface inspection using 3D camera technology in order to reliably detect surface defects on aluminium billets caused by the casting process.
Multiple 3D scanners are mounted on a mobile support. During the measurement the support is horizontally moving along the rotating billet, ensuring that the billet surface is scanned along helical (screw) lines. A 3D range image and a 2D grayscale image are recorded by the scanners. Combined 3D and 2D data is used to detect billet surface defects.
Additionally the 3D data is used to analyse the billet straightness. Scan time depends on number of scanners.