Abstract: The invention provides a welding apparatus and a method for feeding a wire electrode into a position with a defined free wire electrode length from a contact tip of a welding torch of a welding apparatus. Information about a voltage change between the wire electrode on the one hand and a reference electrode on the other hand is used to determine a position of the wire electrode end at the time of the voltage change. The wire electrode can then be moved precisely to the desired position.

Abstract: A method for preparing an automated welding method for a welding process moves a welding torch with a consumable welding wire during a movement phase at a positioning speed from an actual to a desired start position of a welding seam, and bridges the distance of the welding wire end from the workpiece during a creep phase. The creep phase is at least partially carried out during the movement phase. The wire is moved toward the workpiece at a first specified forward feed speed until a first wire end-workpiece contact is detected, moved away from the workpiece after first contact detection and then recurrently moved away from the workpiece, and the contact is interrupted again upon detection of further contacts, and the movement of the welding wire towards the workpiece and movement away from the workpiece after the contact is repeated until the start position is reached.

Abstract: A welding device and a short-circuit welding method uses successive welding cycles having respective arc and short-circuit phases. The method includes: conveying a welding wire from a workpiece, bringing the wire to a final rearward speed in a first rearward conveying phase and then conveying it at that speed until a second rearward conveying phase where the rearward speed is reduced; and conveying the wire toward the workpiece, the welding wire being brought to a final forward speed in a first forward conveying phase and being conveyed at that speed until the beginning of a second forward conveying phase where the forward speed is reduced. The first duration is adapted using a feedforward control and/or feedback control such that the welding wire does not exceed a specified reduced rearward speed in the second rearward conveying phase at the point in time at which the short-circuit is interrupted.

Abstract: A welding device and a short-circuit welding method uses successive welding cycles having respective arc and short-circuit phases. The method includes: conveying a welding wire from a workpiece, bringing the wire to a final rearward speed in a first rearward conveying phase and then conveying it at that speed until a second rearward conveying phase where the rearward speed is reduced; and conveying the wire toward the workpiece, the welding wire being brought to a final forward speed in a first forward conveying phase and being conveyed at that speed until the beginning of a second forward conveying phase where the forward speed is reduced. The first duration is adapted using a feedforward control and/or feedback control such that the welding wire does not exceed a specified reduced rearward speed in the second rearward conveying phase at the point in time at which the short-circuit is interrupted.

Abstract: Method for scanning a workpiece surface (2A) of a metal workpiece (2), in which a blowtorch (3) having a welding wire electrode (4) is moved relative to the workpiece surface (2A) to determine scanning values and a wire end (4A) of the welding wire electrode (4) is repeatedly moved towards the workpiece surface (2A), in each case until contact with the metal workpiece (2) at a scanning position (P) on the workpiece surface (2A) of the metal workpiece (2) is detected, and the wire end (4A) of the welding wire electrode (4) is subsequently moved back, the blowtorch (3) detecting scanning values (d) at scanning positions (P), at least in some cases multiple times, to determine scanning measurement errors.

Abstract: In a method for scanning the surface of metallic workpieces, during scanning, a welding torch with a consumable welding wire is moved over and towards the workpiece surface, until contact of the welding wire with the workpiece is detected, and the welding wire is subsequently moved away from the workpiece. Before scanning, slag-removal is carried out to remove slag at the welding wire end, wherein the welding current is lowered to a minimum, and the welding wire is moved cyclically with a rapid recurrent forward/backward movement over a specified path length toward the workpiece, and by a smaller distance away from the workpiece, until a short circuit between the welding wire and the workpiece is detected, whereupon slag-removal is ended, and upon the detection of no short circuit, slag-removal is repeated, and upon the detection of several short circuits one after the other, slag-removal is ended.

Abstract: Method for scanning the surface (O) of metallic workpieces (W), wherein, during a scanning process before a welding process is carried out, a welding torch (1) with a meltable welding wire (2) is moved over the surface (O) of the workpieces (W), and at predefined times (ti) the welding wire (2) is moved towards the surface (O) of the workpieces (W) until a contact of the welding wire (2) with one of the workpieces (W) is detected, and the position (Pi) of the surface (O) of the workpieces (W) at each time (ti) is determined and stored in the welding power source (4), wherein an edge (K) is determined if the current position (Pi) of the surface (O) of the workpieces (W) exceeds at least one of the stored previous positions (Pi-n) of the surface (O) of the workpieces (W) by a predefined threshold value (S).

Abstract: A method for preparing an automated welding method for a welding process moves a welding torch with a consumable welding wire during a movement phase at a positioning speed from an actual to a desired start position of a welding seam, and bridges the distance of the welding wire end from the workpiece during a creep phase. The creep phase is at least partially carried out during the movement phase. The wire is moved toward the workpiece at a first specified forward feed speed until a first wire end-workpiece contact is detected, moved away from the workpiece after first contact detection and then recurrently moved away from the workpiece, and the contact is interrupted again upon detection of further contacts, and the movement of the welding wire towards the workpiece and movement away from the workpiece after the contact is repeated until the start position is reached.

Abstract: In a method for scanning the surface of metallic workpieces, during scanning, a welding torch with a consumable welding wire is moved over and towards the workpiece surface, until contact of the welding wire with the workpiece is detected, and the welding wire is subsequently moved away from the workpiece. Before scanning, slag-removal is carried out to remove slag at the welding wire end, wherein the welding current is lowered to a minimum, and the welding wire is moved cyclically with a rapid recurrent forward/backward movement over a specified path length toward the workpiece, and by a smaller distance away from the workpiece, until a short circuit between the welding wire and the workpiece is detected, whereupon slag-removal is ended, and upon the detection of no short circuit, slag-removal is repeated, and upon the detection of several short circuits one after the other, slag-removal is ended.

Abstract: The invention relates to a welding process with a consumable welding wire (5), in particular a cold metal transfer (CMT) welding process for build-up welding, and also to a welding apparatus (1) for carrying out such a welding process.

Abstract: Method for scanning the surface (O) of metallic workpieces (W), wherein, during a scanning process before a welding process is carried out, a welding torch (1) with a meltable welding wire (2) is moved over the surface (O) of the workpieces (W), and at predefined times (ti) the welding wire (2) is moved towards the surface (O) of the workpieces (W) until a contact of the welding wire (2) with one of the workpieces (W) is detected, and the position (Pi) of the surface (O) of the workpieces (W) at each time (ti) is determined and stored in the welding power source (4), wherein an edge (K) is determined if the current position (Pi) of the surface (O) of the workpieces (W) exceeds at least one of the stored previous positions (Pi-n) of the surface (O) of the workpieces (W) by a predefined threshold value (S).

Abstract: A short circuit welding method with successive welding cycles with a respective arc phase and short circuit phase includes controlling at least the welding parameters welding current and feed speed of a melting electrode and feeding the electrode toward of a workpiece at a predetermined forward final speed at least during part of the arc phase and away from the workpiece at a predetermined rearward final speed at least during part of the short circuit phase. A device carries out this method. A change in the feed speed and a rearward final speed are predetermined and a welding current is controlled to complete the short circuit phase after reaching the rearward final speed and after 3 ms at the latest and repeat every 8 ms at the latest. The welding parameters are controlled such that the welding cycle duration?8 ms, resulting in a welding frequency?125 Hz.

Abstract: Method for scanning a workpiece surface (2A) of a metal workpiece (2), in which a blowtorch (3) having a welding wire electrode (4) is moved relative to the workpiece surface (2A) to determine scanning values and a wire end (4A) of the welding wire electrode (4) is repeatedly moved towards the workpiece surface (2A), in each case until contact with the metal workpiece (2) at a scanning position (P) on the workpiece surface (2A) of the metal workpiece (2) is detected, and the wire end (4A) of the welding wire electrode (4) is subsequently moved back, the blowtorch (3) detecting scanning values (d) at scanning positions (P), at least in some cases multiple times, to determine scanning measurement errors.

Abstract: A short circuit welding method with successive welding cycles with a respective arc phase and short circuit phase includes controlling at least the welding parameters welding current and feed speed of a melting electrode and feeding the electrode toward of a workpiece at a predetermined forward final speed at least during part of the arc phase and away from the workpiece at a predetermined rearward final speed at least during part of the short circuit phase. A device carries out this method. A change in the feed speed and a rearward final speed are predetermined and a welding current is controlled to complete the short circuit phase after reaching the rearward final speed and after 3 ms at the latest and repeat every 8 ms at the latest. The welding parameters are controlled such that the welding cycle duration?8 ms, resulting in a welding frequency?125 Hz.

Abstract: The invention relates to a method and an apparatus (1) for the production of a welding seam or a three-dimensional structure (26) on a surface of a metallic work piece (14) with the help of a welding torch (7) for carrying out a welding process with a welding wire (9) guided in a welding torch (7), whereby an electric arc (13) is ignited between the welding wire (9) and the work piece (14), and for stabilizing the electric arc (13) a laser (27?) for emitting a laser beam (27) with a maximum power of 2000 W is arranged, with a point of impact being on that position of the work piece (14) where the welding seam or structure (26) is produced. An improvement of the stabilization of the electric arc (13) is obtained if the laser (27?) is connected to a means (28) for the control of the laser (27?), which control means (28) is designed to activate the laser beam (27) prior to the ignition of the electric arc (13).