A welding apparatus for welding workpieces by means of a welding arc which is ignited between a non-consumable welding electrode and the workpieces and produces a molten pool, wherein the welding is performed in a welding process including a plurality of welding cycles, the parameters of which can be set via an interface of the welding apparatus. Each welding cycle of the welding process has a high-current welding phase, during which a high welding current flows, and a low-current welding phase, during which a low welding current flows. In the high-current welding phase and/or in the low-current welding phase of, with the relevant welding cycle being set accordingly, current pulses can be applied, and at the beginning of the high-current welding phase, with the relevant welding cycle being set accordingly, high-frequency ignition pulses can be applied for the contactless ignition of the welding arc.

A method comprising an arc ignition phase (IP), an arc-stabilizing phase (AP) and a stable arc phase (SP). The arc stabilizing phase comprises an initial sub-phase (IS) comprising the step of feeding at least one hot wire (4, 12) at constant feed speed and a main sub-phase (MS) comprising the steps of feeding said hot wire at constant feed speed and feeding at least one cold wire (22) at constant feed speed. The stable arc phase comprises the steps of continuously adjusting the feed speed of the hot wire and continuously adjusting the feed speed of the cold wire. The invention also relates to a welding apparatus (1) for carrying out the method. The welding apparatus comprises a hot wire feeding means (150), a contact means (2), a cold wire feeding means (35) and a control unit (31). The control unit is adapted to control said hot wire feeding means to feed the hot wire at a constant feed speed during the initial sub-phase, feed the hot wire at a constant feed speed during the main sub-phase and to continuously during the stable arc phase adjust the feed speed of the hot wire. The control unit is adapted to control said cold wire feeding means to feed the cold wire at a constant feed speed during the main sub-phase and continuously during the stable arc phase adjust the cold wire feed speed.

A method comprising an arc ignition phase (IP), an arc-stabilizing phase (AP) and a stable arc phase (SP). The arc stabilizing phase comprises an initial sub-phase (IS) comprising the step of feeding at least one hot wire (4, 12) at constant feed speed and a main sub-phase (MS) comprising the steps of feeding said hot wire at constant feed speed and feeding at least one cold wire (22) at constant feed speed. The stable arc phase comprises the steps of continuously adjusting the feed speed of the hot wire and continuously adjusting the feed speed of the cold wire. The invention also relates to a welding apparatus (1) for carrying out the method. The welding apparatus comprises a hot wire feeding means (150), a contact means (2), a cold wire feeding means (35) and a control unit (31). The control unit is adapted to control said hot wire feeding means to feed the hot wire at a constant feed speed during the initial sub-phase, feed the hot wire at a constant feed speed during the main sub-phase and to continuously during the stable arc phase adjust the feed speed of the hot wire. The control unit is adapted to control said cold wire feeding means to feed the cold wire at a constant feed speed during the main sub-phase and continuously during the stable arc phase adjust the cold wire feed speed.

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.

An arc welder includes a welding power supply, a forward/reverse welding wire feeder, and a controller for the power supply and the wire feeder. Welding is implemented by repeating unit welding steps each including a short circuit stage with the welding wire and a base material being short-circuited and an arc stage with an arc being generated between the wire and the material. A transition period continues from a starting point of the arc stage till the wire feeding rate reaches a forward maximum. An average welding current is defined as an average of the welding current during the short circuit and arc stages. Within the transition period, the controller sets a current suppression period during which welding current is smaller than the average welding current. Transition period length T0 and current suppression period length T1 are set to satisfy the inequality 0<T1/T0≤0.8.

An arc welder includes a welding power supply, a forward/reverse welding wire feeder, and a controller for the power supply and the wire feeder. Welding is implemented by repeating unit welding steps each including a short circuit stage with the welding wire and a base material being short-circuited and an arc stage with an arc being generated between the wire and the material. A transition period continues from a starting point of the arc stage till the wire feeding rate reaches a forward maximum. An average welding current is defined as an average of the welding current during the short circuit and arc stages. Within the transition period, the controller sets a current suppression period during which welding current is smaller than the average welding current. Transition period length T0 and current suppression period length T1 are set to satisfy the inequality 0<T1/T0≤0.8.

A welding or additive manufacturing system includes a power supply having a controller which controls operation of the power supply. The power supply provides a current waveform to a contact tip assembly having a first bore terminating at a first exit orifice and a second bore terminating at a second exit orifice. The first exit orifice is configured to deliver a first wire electrode and said second exit orifice is configured to deliver a second wire electrode. The exit orifices are separated from each other by a distance configured to facilitate formation of a bridge droplet between the wire electrodes while preventing solid portions of the first wire electrode delivered through the first bore from contacting solid portions of the second wire electrode delivered through the second bore, during a deposition operation in which the current waveform is conducted to both of the wire electrodes simultaneously through the contact tip assembly.

A welding or additive manufacturing system includes a power supply having a controller which controls operation of the power supply. The power supply provides a current waveform to a contact tip assembly having a first bore terminating at a first exit orifice and a second bore terminating at a second exit orifice. The first exit orifice is configured to deliver a first wire electrode and said second exit orifice is configured to deliver a second wire electrode. The exit orifices are separated from each other by a distance configured to facilitate formation of a bridge droplet between the wire electrodes while preventing solid portions of the first wire electrode delivered through the first bore from contacting solid portions of the second wire electrode delivered through the second bore, during a deposition operation in which the current waveform is conducted to both of the wire electrodes simultaneously through the contact tip assembly.

An example welding system includes: a welding power supply configured to convert input power to welding power; a wire feeder configured to feed welding wire to a welding torch; and control circuitry configured to: in response to an initiation of a welding process, control the wire feeder to feed the welding wire at a first rate while controlling the welding power supply to output the welding power to initiate a welding arc; in response to initiation of the welding arc, control the wire feeder to increase a feed rate of the wire feeder from the first rate to a second rate; and in response to determining that a temperature profile of a heated portion of the welding wire has stabilized, control the wire feeder to change the feed rate of the wire feeder from the second rate to a target wire feed speed.

An example welding system includes: a welding power supply configured to convert input power to welding power; a wire feeder configured to feed welding wire to a welding torch; and control circuitry configured to: in response to an initiation of a welding process, control the wire feeder to feed the welding wire at a first rate while controlling the welding power supply to output the welding power to initiate a welding arc; in response to initiation of the welding arc, control the wire feeder to increase a feed rate of the wire feeder from the first rate to a second rate; and in response to determining that a temperature profile of a heated portion of the welding wire has stabilized, control the wire feeder to change the feed rate of the wire feeder from the second rate to a target wire feed speed.