Abstract: The invention relates to a method of monitoring the welding operation in a stud welding process, wherein a part (19) to be welded is immersed into the melt by moving the part (5) towards a workpiece (17), with a physical quantity depending on the force required for moving the part (5) being measured at least during the phase of immersion of the part (19) to be welded into the melt and the measured gradient of the physical quantity plotted against time being compared with a predetermined set gradient. Furthermore, the invention relates to a stud welding device for carrying out such a method.

Abstract: According to a first embodiment of the method, the stud holder is first positioned without a part to be welded at a certain distance from the tool surface. A part to be welded is then provided. When the welding axle moves towards the workpiece, the path that needs to be travelled in order to bring the part to be welded and the workpiece into contact is detected. Conclusions regarding the presence or absence of a part to be welded are then drawn, based on the previous distance between the stud holder and the workpiece and the path travelled. According to another embodiment, the stud holder is moved towards the workpiece with a part to be welded until contact is detected. If, after contact is detected, further movement of the welding axle is possible as a result of the part to be welded being pushed into the stud holder, this is interpreted as an indication of the presence of a part to be welded.

Abstract: The invention relates to a method for positioning a welding bolt (15), held in a bolt welding head (3), whereby the robot (5), to which the bolt welding head (3) is fixed, moves the bolt welding head sideways until a touch sensor (21) contacts a side wall (25) of a workpiece. The position of the side wall (25) is thus detected and the bolt welding head (3) can be moved through a set amount (Y) into a welding start position, from whence the welding bolt (15) can be welded to the workpiece (9) by the displacement in the direction of travel (V). The welding bolt (15), thus, always has the required separation (Z) from the side wall (25), independent of tolerances in the workpiece.

Abstract: The invention relates to a method for welding a bolt (19) onto a workpiece, using a bolt-welding device and to a bolt-welding device. A force is applied to the drive shaft (11) using a switchable unit (29), said force exerting a resistance against a displacement of the drive shaft (11). The drive shaft (11) is moved by an electromagnetic linear drive (5) acting in an axial direction. The unit (29) can prevent the movement of the drive shaft (11) and can fix the latter in position, in such a way that the linear drive (5) can be switched to a currentless state. In addition, the unit can dampen the movement of the drive shaft (11).

Abstract: The invention relates to a stud welding head with a linear drive (5), a welding pin (11) coupled with said linear drive (5), and a length metering system (7) that determines the position of the welding pin (11) in the stud welding head, said length metering system (7) being an electromagnetic length metering system.