Method and system for teaching tracing of welding seam of electron beam welding machine

The invention discloses a method and system for teaching tracing of a welding seam of an electron beam welding machine. By virtue of a moving working table or a deflection scanning power supply, an electron beam spot movement track intersects with a welding seam track; and when an electron beam spot falls on the welding seam, a secondary electronic signal value Ie apparently becomes smaller suddenly; a midpoint of a position coordinate corresponding to the area where the secondary electronic signal value Ie apparently becomes smaller suddenly is detected and regarded as a central line position of the cross section of the welding seam; and a feature point coordinate is positioned according to the principle. The method and the system disclosed by the invention can be used for quickly and accurately performing teaching tracing on the welding seam, so as to avoid the problem of low precision of a method for positioning the welding seam according to human experience. 本发明公开种电子束焊机焊缝示教寻迹方法及系统，其通过移动工作台或偏扫电源，使得电子束斑点移动轨