Apparatus for seam detection and positioning for laser welding - uses search lasers and working beam focussing optics

摘要

The position of a joint (1) relative to the working point of a working laser beam (9) is determined preferably by means of the measuring beam (14) of a He/Ne search laser (13). The reflection of this beam is let into the existing path of the working beam (9). Preferably a deflecting or decoupling mirror (19) - which has hole or is partially transparent is installed behind the welding head (3) to caputre this reflection by means of a detection system consisting of a collector lens (21), a filter (22), a photo diode (23) and a light-tight housing (20). The installation incorporates a system (6) serving for focussing of the working beam (9) and the measuring beam (14). The mirror (19) can be swivelled about an axis (15) through a certain angle. The mirror (19) has a hole with a diameter corresponding to the measuring beam (14). It is swivelled out of the main beam path after the shutter (10) is opened. As an alternative, the mirror is located (without swivelling capacity) directly in front of the search laser. As a further alternative, the fixed mirror - with a hole diamater slightly larger than the working beam - is located in the path of the working beam. The filter (22) is either a colour or interference filter. USE/ADVANTAGE - In the laser welding technology. It allows utilisation of search lasers which are normally present laser welding installations, and (in contrast to known system) requires no special protection measures against splashes, smoke etc..