DE202013012051U1 - System for starting and using a combined flux-cored wire feed and high-intensity energy source for welding - Google Patents

Abstract

A welding system, comprising: an arc generating power supply that provides an arc generation signal to an electrode to create an arc between the electrode and at least one workpiece (115) to form a molten puddle on the at least one workpiece (115), the arc generation signal comprises a plurality of current pulses; a hot wire power supply (170) that generates a heating signal for heating at least one consumable such that the consumable in the molten puddle melts when the consumable is in contact with the molten puddle, the heating signal comprising a plurality of heating current pulses; and a control unit (195) that synchronizes the arc generation signal and the heating signal to maintain a constant phase angle between the current pulses of the arc generation signal and the heating current pulses, the hot wire power supply (170) and / or the control unit (195) monitoring feedback which is related to the heating signal and compares the feedback to an arc generation threshold, and the hot wire power supply (170) turns off the heating signal when the feedback reaches the arc generation threshold level.

Description

PRIORITY

The present application is a partial refinement of US Patent Application No. 13 / 212,026, and claims priority from US Patent Application No. 13 / 212,026, filed on Aug. 17, 2011, which is hereby incorporated by reference in its entirety and, in turn, is a partial refinement of U.S. Patent Application No. 12 / 352,667, filed January 13, 2009, which is hereby incorporated by reference in its entirety.

TECHNICAL AREA

Certain embodiments relate to flux cored surfacing applications, as well as welding and bonding applications. More specifically, certain embodiments relate to a system for starting and using a combined flux-cored feed and power source system for brazing, plating, building, filling, hardfacing, joining, and welding applications.

BACKGROUND

The conventional flux-cored method of welding (for example, a gas-tungsten arc welding (GTAW) filler wire method) provides higher deposition rates and welding speeds than conventional arc welding alone. The cored wire leading to a burner is resistance heated by a separate power supply. The wire is passed through a contact tube in the direction of a workpiece and extends beyond the tube. The extension can be resistance heated. The extension can be resistance heated as it approaches the puddle. A tungsten electrode may be used to heat and melt the workpiece to form the weld puddle. The power supply provides much of the energy needed to reflow the flux-cored wire. In some cases, the wire feed may slip or falter, and the current in the wire may create an arc between the tip of the wire and the workpiece. The extra heat of such an arc can cause burn through, spatter, and poor surface quality. The risk of creating such an arc is greater at the beginning of the process where the wire initially contacts the workpiece at a small point. If the initial current in the wire is too high, the spot may burn away, creating an arc.

Further limitations and disadvantages of conventional, conventional and proposed approaches will become apparent to those skilled in the art from a comparison of such approaches with embodiments of the present invention set forth in the remainder of the present application with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention include a system for starting and using a combined cored wire feeder and power source system. A first embodiment of the present invention includes a system for starting and using a combined wire feed and power source system for brazing, cladding, build up, fill, hardfacing, welding, and bonding applications. The system is configured to apply a sense voltage between at least one ohmic flux-cored wire and a workpiece via a current source and advance a distal end of the at least one ohmic flux-cored wire toward the workpiece. The system is further configured to sense when the distal end of the at least one ohmic flux-cored wire first makes contact with the workpiece. The system is further configured to turn off the power source to the at least one resistive flux-cored wire over a defined time interval in response to the sensing. The system is further configured to turn on the power source at one end of the defined time interval to flow heating current through at least one resistive flux-cored wire. The system is further configured to apply energy from a high-intensity energy source to the workpiece to heat the workpiece, at least while the heating current is flowing. The high intensity power source may include at least one of a laser device, a plasma arc welding (PAW) device, a gas tungsten arc welding (GTAW) device, a gas metal arc welding (GMAW) device, a Flux Cored Arc Welding (FCAW) Device and Submerged Arc Welding (SAW) Device.

These and other features of the claimed invention, as well as details of illustrated embodiments of the invention, will be better understood by reference to the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

1 FIG. 12 illustrates a functional block diagram of an exemplary embodiment. FIG a combined cored wire feeder and power source system for brazing, cladding, build up, fill and hardfacing applications;

2 FIG. 4 illustrates a flowchart of one embodiment of a start-up procedure performed by the system of FIG 1 is used;

3 FIG. 12 illustrates a flowchart of one embodiment of a post-startup process performed by the system of FIG 1 is used;

4 FIG. 12 illustrates a first exemplary embodiment of a pair of voltage and current waveforms that are used with the post-start method of FIG 3 linked;

5 FIG. 12 illustrates a second exemplary embodiment of a pair of voltage and current waveforms that are used with the post-start method of FIG 3 linked;

6 and 6A illustrate another exemplary embodiment of the present invention used to perform a welding operation;

7 . 7A and 7B illustrate further exemplary embodiments of welding with the present invention;

6 illustrates another exemplary embodiment of simultaneously joining two sides of a weld joint;

9 illustrates another exemplary embodiment of welding with the present invention;

10 illustrates another exemplary embodiment of the present invention for welding a multiple metal fiber and wire weld joint;

11A to 11C show exemplary embodiments of contact tips used with embodiments of the present invention;

12 illustrates a hot wire power supply system according to an embodiment of the present invention;

13A -C illustrate voltage and current waveforms generated by exemplary embodiments of the present invention;

14 illustrates another welding system according to an exemplary embodiment of the present invention;

15 Fig. 12 illustrates an exemplary embodiment of a weld puddle created by an embodiment of the present invention;

16A to 16F illustrate exemplary embodiments of weld puddles and a laser beam application in accordance with embodiments of the present invention;

17 illustrates a welding system according to another exemplary embodiment of the present invention;

18 FIG. 12 illustrates an exemplary embodiment of a descent circuit that may be used in embodiments of the present invention; FIG.

19 FIG. 11 illustrates an exemplary embodiment of a vapor extraction nozzle according to the present invention; FIG.

20 Figure 1 illustrates an exemplary embodiment of another welding system of the present invention;

21 FIG. 10 illustrates an example embodiment of a welding operation according to an embodiment of the present invention; FIG.

22A - 22C illustrate exemplary embodiments of current waveforms used by welding systems of the present invention;

23 FIG. 12 illustrates an exemplary embodiment of another welding operation according to an embodiment of the present invention; FIG.

24 illustrates another exemplary embodiment of current waveforms that may be used with embodiments of the present invention;

25 FIG. 12 illustrates an exemplary embodiment of another welding operation that may be used with embodiments of the invention; FIG.

25A FIG. 12 illustrates an exemplary embodiment of a current waveform consistent with that in FIG 25 shown embodiment can be used;

26 FIG. 10 illustrates an exemplary embodiment of another welding operation using adjacent arc welding operations; FIG.

27 Fig. 10 illustrates an exemplary embodiment of another welding operation of the present invention; and

28 illustrates another exemplary embodiment of a welding operation of the present invention using a magnetic steering.

DETAILED DESCRIPTION

The term "build-up welding" is used herein in a broad sense and may refer to any application, such as brazing, plating, build up, fill and hardfacing. For example, in a "braze" application, a filler metal is distributed between closely spaced surfaces of a joint by capillary action, while in a "braze" application, the filler metal is allowed to flow into a gap. However, for the purposes of the present text, both techniques are broadly referred to as build-up welding applications.

1 FIG. 12 illustrates a functional block diagram of an exemplary embodiment of a combined flux-cored feeder and power source system. FIG 100 for performing brazing, cladding, building, filling, hardfacing, joining and welding applications. The system 100 contains a laser subsystem that is capable of producing a laser beam 110 on a workpiece 115 to focus around the workpiece 115 to warm up. The laser subsystem is a high-intensity energy source. The laser subsystem may be any form of high energy laser source including, for example, carbon dioxide, Nd: YAG, Yb disc, YB fiber, fiber transfer, or direct diode laser systems. Furthermore, even white light or quartz laser systems can be used if they have enough energy. Other embodiments of the system may include at least one of an electron beam, a plasma arc welding subsystem, a gas tungsten arc welding subsystem, a gas metal arc welding subsystem, a flux cored arc welding subsystem, and a subpowder. Arc welding subsystem to serve as the high-intensity power source. The following specification repeatedly refers to the laser system, the laser beam and the laser power supply; however, it should be understood that these references are merely exemplary in nature, as any high-intensity energy source may be used. For example, a high intensity energy source can provide at least 500 W / cm ² . The laser subsystem includes a laser device 120 and a laser power supply 130 that are operatively connected to each other. The laser power supply 130 provides the energy to operate the laser device 120 ,

The system 100 Also includes a hot fill wire feeder subsystem capable of having at least one ohmic flux cored wire 140 to provide a contact with the workpiece 115 near the laser beam 110 manufacture. Of course, it goes without saying that with the mention of the workpiece 115 in the present text, the molten puddle as part of the workpiece 115 is viewed, so the reference to a contact with the workpiece 115 also contains a contact with the puddle. The hot fill wire feeder subsystem includes a cored wire feeder 150 , a contact tube 160 and a hot wire power supply 170 , During operation, the cored wire becomes 140 , the laser beam 110 precedes, by electric current from the hot wire power supply 170 between the contact tube 160 and the workpiece 115 is actively connected, resistance heated. According to an embodiment of the present invention, the hot wire power supply is 170 a pulsed DC power supply, although AC or other types of power are also possible. The wire 140 is from the Fülldrahtzufuhrvorrichtung 150 through the contact tube 160 in the direction of the workpiece 115 guided and extends over the pipe 160 out. The extension section of the wire 140 is so resistance heated that the extension portion approaches or reaches the melting point before it contacts a weld puddle on the workpiece. The laser beam 110 serves to melt a part of the base metal of the workpiece 115 to form a sweat puddle, and also serves to melt the wire 140 on the workpiece 115 , The power supply 170 provides a large part of the energy needed to fill the cored wire 140 widerstandszuschmelzen. The feeder subsystem may, according to certain other embodiments of the present invention, be capable of simultaneously providing one or more wires. For example, a first wire may be used for hardfacing and / or corrosion protection of the workpiece, and a second wire may be used to reinforce the structure of the workpiece.

The system 100 further includes a motion control subsystem capable of the laser beam 110 (the energy source) and the ohmic flux-cored wire 140 in the same direction 125 along the workpiece 115 (at least in the relative sense) to move in such a way that the laser beam 110 and the ohmic flux-cored wire 140 in a solid Stay in contact with each other. According to various embodiments, the relative movement between the workpiece 115 and the laser / wire combination can be achieved by holding the workpiece 115 physically moved or by the laser device 120 and the wire feeder subsystem moves. In 1 The motion control subsystem includes a motion control unit 160 that with a robot 190 is actively connected. The motion control unit 180 controls the movement of the robot 190 , The robot 190 is with the workpiece 115 operatively connected (eg mechanically attached) to the workpiece 115 so in the direction 125 to move that, the laser beam 110 and the wire 140 practically on the workpiece 115 move along. According to an alternative embodiment of the present invention, the laser device 110 and the contact tube 160 be integrated in a single head. The head can travel along the workpiece via a motion control subsystem operatively connected to the head 115 to be moved.

In general, there are various methods of how to move a high intensity power source and a hot wire relative to a workpiece. For example, when the workpiece is round, the high intensity energy source and the hot wire may be stationary, and the workpiece may be rotated under the high intensity energy source and the hot wire. Alternatively, a robotic arm or linear pulling device may move parallel to the round workpiece, and while the workpiece is being rotated, the high intensity energy source and hot wire may move continuously or incrementally once per revolution, for example material onto the surface of the round workpiece apply. If the workpiece is flat or at least not round, then the workpiece can be moved under the high intensity power source and the hot wire, as in FIG 1 shown. However, a robotic arm or device, or even a carriage mounted on a carrier, may also be used to move a high intensity power source and a hot wire head relative to the workpiece.

The system 100 further includes a sense and current control subsystem 195 that with the workpiece 115 and the contact tube 160 operatively connected (ie practically with the output of the hot wire power supply 170 connected) and is capable of a potential difference (ie, a voltage V) between the workpiece 115 and the hot wire 140 and a current (I) through the workpiece 115 and the hot wire 140 to eat. The sensing and current control subsystem 195 Further, it may be capable of calculating a resistance value (R = V / I) and / or a power value (P = V · I) from the measured voltage and the measured current. In general, if the hot wire 140 in contact with the workpiece 115 stands, the potential difference between the hot wire 140 and the workpiece 115 zero volts or very close to zero volts. As a result, the sense and current control subsystem 195 sensing when the ohmic flux cored wire 140 in contact with the workpiece 115 stands, and is with the hot wire power supply 170 operatively connected to further be able to control the current flow through the ohmic flux-cored wire 140 in response to sensing, as described in greater detail below. According to another embodiment of the present invention, the sense and current control unit 195 an integral part of the hot wire power supply 170 be.

According to an embodiment of the present invention, the motion control unit 180 further with the laser power supply 130 and / or the sensing and current control unit 195 be actively connected. In this way, the motion control unit can 180 and the laser power supply 130 communicate with each other so that the laser power supply 130 knows when the workpiece 115 moves, and thus the motion control unit 180 knows if the laser device 120 is active. Similarly, the motion control unit 180 and the sense and current control unit 195 communicate with each other in this way, so that the sensing and power control unit 195 knows when the workpiece 115 moves, and thus the motion control unit 190 knows when the hot fill wire feeder subsystem is active. Such communication can be used for activities between the various subsystems of the system 100 to coordinate.

2 illustrates a flowchart of one embodiment of a startup method 200 that through the system 100 from 1 is used. In step 210 becomes a sense voltage between at least one ohmic flux-cored wire 140 and a workpiece 115 via a power source 170 created. The sensing voltage can be through the hot wire power supply 170 under the command of the sense and current control unit 195 be created. Furthermore, according to an embodiment of the present invention, the applied sense voltage does not provide enough energy to the wire 140 to heat appreciably. In step 220 becomes a distal end of the at least one ohmic flux-cored wire 140 in the direction of the workpiece 115 advance pushed. The feed is through the wire feeder 150 executed. In step 230 is sensed when the distal end of the at least one ohmic flux-cored wire 140 first contact with the workpiece 115 manufactures. For example, the sense and current control unit 195 the hot wire power supply 170 instruct a very low current level (for example 3 to 5 A) through the hot wire 140 supply. Such sensing may be provided by the sense and current control unit 195 by making a potential difference of about zero volts (for example 0.4 V) between the flux cored wire 140 (for example via the contact tube 160 ) and the workpiece 115 measures. If the distal end of the filler wire 140 with the workpiece 115 is short circuited (ie making contact with the workpiece), there must be no significant voltage level (above zero volts) between the flux cored wire 140 and the workpiece 115 exist.

In step 240 becomes the power source 170 to the at least one ohmic flux-cored wire 140 turned off in response to sensing over a defined time interval (for example, a few milliseconds). The sensing and power control unit 195 can be the power source 170 instruct to switch off. In step 250 becomes the power source 170 turned on at one end of the defined time interval to a heating current through the at least one ohmic flux-cored wire 140 to flow. The sensing and power control unit 195 can be the power source 170 instruct to turn on. In step 260 Energy becomes a high-intensity energy source 110 to the workpiece 115 applied to the workpiece 115 to heat, at least while the heating current is flowing.

Optionally, the procedure 200 Includes: stopping the advance of the wire 140 in response to the sensing, restarting the advancement (ie re-advancing) of the wire 140 at the end of the defined time interval, and verify that the distal end of the filler wire 140 still in contact with the workpiece 115 is before the heating current is applied. The sensing and power control unit 195 can the wire feeder 150 instruct, stop feeding, and can system 100 instruct to wait (for example, a few milliseconds). In such an embodiment, the sense and current control unit is 195 with the wire feeder 150 operatively connected to the wire feeder 150 instruct, start and stop. The sensing and power control unit 195 can be the hot wire power supply 170 instruct to apply the heating current to the wire 140 to warm, and the wire 140 again in the direction of the workpiece 115 supply.

Once the startup procedure has been performed, the system can 100 enter a post-start operating mode, the laser beam 110 and the hot wire 140 in relation to the workpiece 115 be moved to a brazing application, a plating application, a build-up application, a hard-facing application or a welding or bonding operation. 3 illustrates a flowchart of one embodiment of a post-start process 300 that through the system 100 from 1 is used. In step 310 become a high-intensity energy source (for example, the laser device 120 ) and at least one ohmic flux-cored wire 140 such along a workpiece 115 that moves the distal end of the at least one ohmic flux-cored wire 140 the high-intensity energy source (for example, the laser device 120 ) is ahead or at the same height with it, in such a way that energy (for example the laser beam 110 ) from the high-intensity energy source (for example, the laser device 120 ) and / or the heated workpiece 115 (ie the workpiece 115 is through the laser beam 110 heated) the distal end of the filler wire 140 on the workpiece 115 melts while the at least one ohmic flux-cored wire 140 in the direction of the workpiece 115 is supplied. The motion control unit 180 instructs the robot 130 on, the workpiece 115 in relation to the laser beam 110 and the hot wire 140 to move. The laser power supply 130 provides the energy to the laser device 120 to operate and so the laser beam 110 to build. The hot wire power supply 170 feeds electric current into the hot wire 140 as by the sense and current control unit 195 was instructed.

In step 320 is sensed whenever the distal end of the at least one ohmic flux-cored wire 140 just before that is the contact with the workpiece 115 to lose (ie a look-ahead capability is provided). Such sensing may be accomplished by a lookahead circuit within the sense and current controller 195 can be accomplished, which senses a rate of change of one of the following: a potential difference between the flux cored wire 140 and the workpiece 115 (dv / dt), a current through the cored wire 140 and the workpiece 115 (di / dt), a resistance between the filler wire 140 and the workpiece 115 (dr / dt), or a power through the cored wire 140 and the workpiece 115 (Dp / dt). When the rate of change exceeds a predetermined value, the sense and current control unit predicts 195 formally, that a loss of contact is imminent. Such advance circuits are familiar to those skilled in the art of arc welding.

If the distal end of the wire 140 due to heating becomes molten, the distal end may begin to move away from the wire 140 on the workpiece 115 pinch off. For example, at this moment, the potential difference or stress increases because the cross-section of the distal end of the wire rapidly decreases as it pinches off. That's what the system can do 100 by anticipating such a rate of change, when the distal end is about to approach itself cut off and contact with the workpiece 115 to lose. In addition, when the contact is completely lost, a potential difference (ie, a voltage level) significantly greater than zero volts may be detected by the sense and current control unit 195 be measured. This potential difference could cause (undesirably) an arc between the new distal end of the wire 140 and the workpiece 115 arises when the action in step 330 is not taken. Of course the wire needs 140 In other embodiments, there is no appreciable constriction, but rather flows evenly into the puddle while maintaining a nearly constant cross-section into the puddle.

In step 330 becomes the flow of the heating current through the at least one ohmic flux-cored wire 140 in response to sensing that the distal end of the at least one ohmic flux-cored wire 140 just before that is the contact with the workpiece 115 losing, turned off (or at least significantly reduced, for example, by 95%). When the sensing and power control unit 195 determines that the contact is about to get lost, so the control unit points out 195 the hot wire power supply 170 into the hot wire 140 cut off (or at least significantly reduce) fed-in power. In this way, the formation of an unwanted arc is avoided, whereby unwanted effects, such as spattering or burn-through, are prevented.

In step 340 is sensed whenever the distal end of the at least one ohmic flux-cored wire 140 again a contact with the workpiece 115 produces, because the wire 140 continue in the direction of the workpiece 115 is pushed forward. Such sensing can be accomplished by the sensing and power control unit 195 a potential difference of about zero volts between the cored wire 140 (for example via the contact tube 160 ) and the workpiece 115 measures. If the distal end of the filler wire 140 with the workpiece 115 shorted (ie making contact with the workpiece), there may not be a significant voltage level above zero volts between the flux cored wire 140 and the workpiece 115 , The phrase "makes contact again" in the present text means the situation where the wire is 140 in the direction of the workpiece 115 advances and the measured voltage between the wire 140 (for example via the contact tube 160 ) and the workpiece 115 is about zero volts, regardless of whether the distal end of the wire 140 actually completely from the workpiece 115 pinch off or not. In step 350 For example, in response to sensing that the distal end of the at least one ohmic flux-cored wire is re-contacting the workpiece, the heating current is again passed through the at least one ohmic flux-cored wire. The sensing and power control unit 195 can be the hot wire power supply 170 instruct to re-feed the heating current to warm the wire 140 continue. This process can be continued throughout the duration of the build-up welding application.

For example, illustrated 4 a first exemplary embodiment of a pair of voltage and current waveforms 410 respectively. 420 that with the post-start procedure 300 from 3 are linked. The voltage waveform 410 is through the sensing and power control unit 195 between the contact tube 160 and the workpiece 115 measured. The current waveform 420 is done by means of the sense and current control unit 195 through the wire 140 and workpiece 115 measured through.

Whenever the distal end of the ohmic flux-cored wire 140 just before that is the contact with the workpiece 115 losing exceeds the rate of change of the voltage waveform 410 (ie, dv / dt) a predetermined threshold, indicating that pinching is imminent (see the descent at point 411 the waveform 410 ). Instead, as alternatives may be a rate of change of the current through the flux-cored wire 140 and the workpiece 115 (di / dt), a rate of change of resistance between the flux cored wire 140 and the workpiece 115 (dr / dt) or a rate of change of power through the cored wire 140 and the workpiece 115 (dp / dt) are used to indicate that pinching is imminent. Such rate of change prediction techniques are familiar to those skilled in the art. At this moment, the sensing and current control unit points 195 the hot wire power supply 170 on, the flow of current through the wire 140 switch off (or at least significantly reduce).

When the sensing and power control unit 195 feels that the distal end of the filler wire 140 after a time interval 430 again a good contact with the workpiece 115 (for example, if the voltage level at point 412 falls to about zero volts), so the sense and current control unit 195 the hot wire power supply 170 on, the current flow through the ohmic flux-cored wire 140 in the direction of a predetermined output level 450 to rise (see rise 425 ). In accordance with an embodiment of the present invention, the increase begins at a set point value 440 , This process is repeated when the energy source 120 and the wire 140 relative to the workpiece 115 move and the wire 140 by means of the wire feeder 150 in the direction of the workpiece 115 forward pushes. In this way, the contact between the distal end of the wire 140 and the workpiece 115 largely retained, and it prevents an arc between the distal end of the wire 140 and the workpiece 115 arises. An increase in the heating current helps to prevent a rate of change of the voltage from being inadvertently interpreted as a pinch-off state or an arcing state when there is no such state. Any large change in current could cause a faulty voltage measurement due to the inductance in the heating circuit. As the current is gradually increased, the effect of inductance is reduced.

5 illustrates a second exemplary embodiment of a pair of voltage and current waveforms 510 respectively. 520 using the post-start procedure of 3 are linked. The voltage waveform 510 is through the sensing and power control unit 195 between the contact tube 160 and the workpiece 115 measured. The current waveform 520 is done by means of the sense and current control unit 195 through the wire 140 and the workpiece 115 measured through.

Whenever the distal end of the ohmic flux-cored wire 140 just before that is the contact with the workpiece 115 losing exceeds the rate of change of the voltage waveform 510 (ie, dv / dt) a predetermined threshold, indicating that pinching is imminent (see the descent at point 511 the waveform 510 ). Instead, as alternatives may be a rate of change of the current through the flux-cored wire 140 and the workpiece 115 (dl / dt), a rate of change of resistance between the filler wire 140 and the workpiece 115 (dr / dt) or a rate of change of power through the cored wire 140 and the workpiece 115 (dp / dt) are used to indicate that pinching is imminent. Such rate of change prediction techniques are familiar to those skilled in the art. At this point, the sense and current control unit points 195 the hot wire power supply 170 on, the flow of current through the wire 140 switch off (or at least significantly reduce).

When the sensing and power control unit 195 feels that the distal end of the filler wire 140 after a time interval 530 again a good contact with the workpiece 115 has (for example, the voltage level at point 512 falls to about zero volts), so the sense and current control unit 195 the hot wire power supply 170 on, the heating current (see heating current level 525 ) through the ohmic flux-cored wire 140 to flow. This process is repeated while the energy source 120 and the wire 140 relative to the workpiece 115 move and while the wire 140 through the wire feeder 150 in the direction of the workpiece 115 is pushed forward. In this way, the contact between the distal end of the wire 140 and the workpiece 115 largely retained, and it prevents an arc between the distal end of the wire 140 and the workpiece 115 arises. Since the heating current does not increase gradually in this case, certain voltage measurements due to the inductance in the heating circuit may be ignored as inadvertent or erroneous.

In summary, a method and system for starting and using a combined wire feed and power source system for brazing, cladding, build up, fill, and hardfacing applications is disclosed. High-intensity energy is applied to a workpiece to heat the workpiece. One or more ohmic cored wires are - along with the high-energy energy or this leading - fed in the direction of the workpiece. The sensing is enabled when a distal end of the one or more ohmic cored wires make contact with the workpiece at or near the applied high-intensity energy. The electric heating current to the one or more ohmic cored wires is controlled on the basis of whether or not the distal end of the one or more ohmic cored wires is in contact with the workpiece. The applied high-intensity energy and the one or more ohmic cored wires are moved in the same direction along the workpiece in a fixed relationship to each other.

In other exemplary embodiments, systems and methods of the present invention are used for welding or jointing operations. The embodiments discussed above focused on using filler metals in build-up welding operation. However, aspects of the present invention may also be used in welding and bonding applications in which workpieces are joined by means of welding operations and using a filler metal. While the embodiments, systems, and methods described above relate to the application of a filler metal, they are similar to those used in welding operations, as described in greater detail below. Therefore, it is understood in the following discussions that the above discussions are generally valid unless otherwise specified. In addition, the following discussion may refer to the 1 to 5 contain.

It is known that welding or joining operations typically combine a plurality of workpieces in a welding operation, wherein a filler metal is combined with at least a portion of the workpiece metal to form a To form weld joint. Due to the desire for higher production throughput in welding operations, there is an unrelenting demand for faster welding operations that do not result in weld seams of below average quality. In addition, there is a need for systems that can rapidly weld under harsh environmental conditions, such as at remote work sites. As described below, exemplary embodiments of the present invention provide significant advantages over current welding technologies. These advantages include, for example, reduced total heat input resulting in little distortion of the workpiece, very high welding feed rates, very low welding spatter rates, unshielded welding, welding of clad or coated materials at high speeds with few spatters at most, and welding of complex materials at high speeds speeds.

In exemplary embodiments of the present invention, very high welding speeds compared to arc welding can be obtained using coated workpieces, which typically require significant preparatory work and represent much slower welding processes using arc welding techniques. As an example, the following discussion focuses on welding galvanized workpieces. The galvanization of metal serves to improve the corrosion resistance of the metal and is desirable in many industrial applications. However, conventional welding of galvanized workpieces can be problematic. More specifically, during welding, the zinc evaporates in the galvanization, and these zinc vapors can be trapped in the weld puddle as the puddle solidifies, resulting in porosity. This porosity affects the strength of the weld joint. Because of this, existing welding techniques require a first step of galvanizing removal or galvanizing at lower processing speeds and with a certain degree of defects, which is inefficient and causes delays or requires the welding process to be slow. By slowing down the process, the sweat puddle remains molten for longer, allowing the vaporized zinc to escape. However, due to the slow speed, the production rates are low and the total heat input into the weld can be high. Other coatings that may cause similar problems include: paints, stamped lubricants, glass liners, aluminized coatings, surface heat treatments, nitriding or carbonation treatments, plating treatments, or other evaporative coatings or materials. Exemplary embodiments of the present invention eliminate these problems, as explained below.

We turn to the 6 and 6A (Cross-sectional or side view), where a representative weld overlap is shown. In this figure, two coated (for example galvanized) workpieces W1 / W2 are to be joined with an overlap weld. The overlap joint surfaces 601 and 603 are first with the coating as well as the surface 605 of the workpiece W1 covered. In a typical welding operation (for example, GMAW), portions of the covered surface become 605 brought into a molten state. This is due to the typical penetration depth of a standard welding operation. Because the surface 605 is brought to a molten state, the coating evaporates on the surface 605 but because the distance of the surface 605 from the surface of the weld puddle, the gases may become trapped as the weld puddle solidifies. This does not happen in embodiments of the present invention.

As in the 6 and 6A shown is a laser beam 110 from the laser device 120 directed to the weld, more precisely to the surfaces 601 and 603 , The laser beam 110 has an energy density sufficient to melt portions of the weld surfaces to melt puddles 601A and 603A create, creating a general puddle. In addition, a cored wire 140 , which is resistance heated according to the above description, directed to the weld puddle to provide the required fill material for the weld bead. Unlike most welding processes, the flux cored wire 140 during the welding process makes contact with the welding puddle and is immersed in the welding puddle. This is because this process does not use a welding arc around the flux-cored wire 140 Instead, simply melt the filler wire into the weld puddle.

Because the cored wire 140 is preheated to or near its melting point, its presence in the puddle of sweat is not likely to significantly cool or solidify the puddle, and the filler wire 140 is quickly consumed in the sweat puddle. The general operation and control of the cored wire 140 are as previously described with respect to the build-up welding embodiments.

Because the laser beam 110 precisely focused and on the surfaces 601 / 603 can be addressed, the penetration depth for the puddles 601A / 603A be precisely controlled. By carefully controlling this depth, embodiments of the present invention prevent unnecessary burn-in or melting of the surface 605 , Because the surface 605 is not overly melted, no coating on the surface 605 evaporates and is not trapped in the sweat puddle. In addition, any coating on the surface of the weld joint 601 and 603 in a simple way by the laser beam 110 evaporates and this gas can escape from the weld zone before the weld puddle solidifies. It is contemplated that a gas exhaust system may be used to assist in the removal of vaporized coating materials.

Because the depth of weld puddle firing can be precisely controlled, the speed of welding coated workpieces can be significantly increased while significantly minimizing or eliminating porosity. Some arc welding systems can achieve good feed speeds for welding, but at higher speeds, problems such as porosity and weld spatter can occur. In exemplary embodiments of the present invention, very high feed rates with possibly low porosity or spatter (as discussed herein) can be achieved, and even feed rates in excess of 50 inches / min can easily be achieved for many different types of welding operations. Embodiments of the present invention can achieve weld advance speeds in excess of 80 inches / minute. In addition, other embodiments can achieve feed rates in the range of 100 to 150 inches / min with minimal or no spatter (as discussed herein). Of course, the speeds achieved depend on workpiece properties (thickness and composition) and wire characteristics (eg, diameter), but these speeds are readily achievable in many different welding and bonding applications when employing embodiments of the present invention. In addition, these speeds can be achieved either with a 100% carbon dioxide gas, or they can be achieved entirely without shielding gas. Furthermore, these feed rates can be achieved without removing surface coatings prior to forming the weld puddle and welding. Of course, it is considered that even higher feed rates can be achieved. Further, because the heat input into the weld is reduced, these high speeds can be achieved with thinner workpieces 115 are achieved, which usually have a slower welding speed, because the heat must be kept low to avoid warping. Embodiments of the present invention can not only achieve the above-described high feed rates with possibly low porosity or few spatter, but can also achieve very high deposition rates with little mixing. More specifically, embodiments of the present invention can achieve deposition rates of 10 lb / hr or higher without shielding gas and with at most low porosity or spatter. In some embodiments, the deposition rate is in the range of 10 to 20 lb / hr.

In the exemplary embodiments of the present invention, these extremely high feed rates are achieved at best with little porosity and at most little spatter. The porosity of a weld can be determined by examining a cross-section and / or length of the weld bead to determine the porosity ratios. The cross-sectional porosity ratio is the total area of porosity in a particular cross-section over the total cross-sectional area of the weld at that point. The longitudinal porosity ratio is the accumulated total length of the pores in a certain unit length of the weld joint. Embodiments of the present invention can achieve the above-described feed rates with a cross-sectional porosity between 0 and 20%. That is, a weld bead without bubbles or voids has 0% porosity. In other exemplary embodiments, the cross-sectional porosity may range from 0 to 10%, and in another exemplary embodiment may be in the range of 2 to 5%. It is understood that in some welding applications a certain degree of porosity is acceptable. Moreover, in exemplary embodiments of the invention, the longitudinal porosity of the weld is in the range of 0 to 20% and 0 to 10%. In other exemplary embodiments, the longitudinal pore ratio is in the range of 1 to 5%. That is, for example, welds having a cross-sectional porosity in the range of 2 to 5% and a longitudinal porosity ratio of 1 to 5% can be produced.

Further embodiments of the present invention can weld at the above-mentioned feed rates with only a few weld spatters. Spatters are generated when droplets of the weld puddle are caused to splash outside the weld zone. If spatters occur, so They can affect the quality of the weld and can cause production delays, since they usually have to be cleaned off the workpiece after the welding process. That is, welding at high speed without spattering has a high utility. Embodiments of the present invention can weld at the above-described high feed rates with a weld spatter factor in the range of 0 to 0.5, where the spatter factor is the weight of weld spatter over a given feed distance X (in mg) over the weight of the consumed filler wire 140 over the same distance X (in kg) is. This means: Spatter factor = (spatter weight (mg) / consumed cored wire Weight (kg))

The distance X should be a distance that allows a representative sampling of the weld joint. That is, if the distance X is too short, for example 0.5 inches, then it may not be representative of the weld. That is, a weld joint with a weld spatter factor of 0 would have no weld spatter for the consumed filler wire over the distance X, and a weld with a spatter factor of 2.5 would have 5 mg spatter on 2 kg of consumed filler wire. In an exemplary embodiment of the present invention, the spatter factor is in the range of 0 to 1. In another exemplary embodiment, the spatter factor is in the range of 0 to 0.5. In another exemplary embodiment of the present invention, the spatter factor is in the range of 0 to 0.3. It should be appreciated that embodiments of the present invention may achieve the weld spatter factor ranges described above with or without the use of external shielding, such as shielding gas or flux shielding. Further, the weld spatter factor ranges described above can be achieved in welding uncoated or coated workpieces, including galvanized workpieces, without having to remove the electroplating prior to the welding operation.

There are a number of methods for measuring weld spatters for a weld joint. One method may include the use of a "spatter boat". In one such method, a representative weld sample is placed in a container of sufficient size to catch all, or almost all, spatter weld generated by a weld bead. The container or portions of the container, such as the top, may move with the welding process to ensure that the weld spatter is captured. As a rule, the boat is made of copper, so that the spatter does not adhere to the surfaces. The representative weld is made over the bottom of the container so that all spatters generated during welding fall into the container. During welding, the amount of consumed welding wire is monitored. After the welding is completed, the weld sprayer boat is weighed with a sufficiently accurate device to determine the difference, if any, between the weight of the container before and after welding. This difference represents the weight of the spatter and is then divided by the amount in kg of the consumed filler wire. Alternatively, if they do not adhere to the boat, the spatter can be removed and weighed alone.

As described above, using the laser device allows 120 a precise control of the depth of the weld puddle. Furthermore, using the laser allows 120 a slight adjustment of the size and depth of the sweat puddle. That's because the laser beam 110 can be easily focused and defocused or that its beam intensity can be changed very easily. Thanks to these capabilities, the heat distribution to the workpieces W1 and W2 can be precisely controlled. This control allows the formation of very narrow welding puddles for precise welding as well as minimizing the size of the welding zone on the workpiece. This also offers advantages in minimizing the areas of the workpiece that are not affected by the weld bead. Specifically, the areas of the workpiece adjacent the weld bead have minimal effects on the welding operation, which is often not the case with arc welding operations.

In exemplary embodiments of the present invention, the shape and / or intensity of the beam 110 adjusted or changed during the welding process. For example, it may be necessary to change the penetration depth at certain locations on a workpiece or to change the size of the weld bead. In such embodiments, the shape, intensity and / or size of the beam 110 be adjusted during the welding process so that the required change in the welding parameters is brought about.

As described above, the flux-cored wire strikes 140 on the same sweat puddle as the laser beam 110 , In an exemplary embodiment, the flux cored wire strikes 140 at the same place on the welding puddle as the laser beam 110 , However, the cored wire can 140 in other exemplary embodiments, in a spatial distance to the laser beam 110 hit the same sweat puddle. In the in 6A In the embodiment shown, the filler wire rushes 140 during the welding operation the beam 110 after. However, this is not necessary because the flux-cored wire 140 can also be positioned in the leading position. The present invention is not limited in this respect since the flux-cored wire 140 also in other places relative to the beam 110 can be positioned as long as the filler wire 140 meets the same puddle as the jet 110 ,

The embodiment described above has been described with reference to workpieces having a coating such as electroplating. However, embodiments of the present invention may also be used on workpieces that do not have a coating. More specifically, the same welding process as described above can be carried out with uncoated workpieces. Such embodiments achieve the same performance attributes as described above with respect to coated metals.

Moreover, exemplary embodiments of the present invention are not limited to the welding of steel workpieces, but may also be used for the welding of aluminum or more complex metals, as will be described below.

Another advantageous aspect of the present invention relates to protective gas. In a typical arc welding process, a shielding gas or shielding flux is used to prevent the oxygen and nitrogen in the atmosphere, or other deleterious elements, from interacting with the weld puddle and metal transfer. Such interference can be detrimental to the quality and appearance of the weld. Therefore, in almost all arc welding processes, shielding is provided by means of an externally supplied shielding gas, or shielding gas, generated by consuming an electrode with a flux thereon (e.g., stick electrode, flux-center electrode, etc.) or granular supplied from the outside Flux (for example, submerged arc welding) provided. In addition, in some welding operations, such as welding of specialized metals or welding of galvanized workpieces, a special inert gas mixture must be used. Such mixtures can be extremely expensive. In addition, when welding in extreme environments, it is often difficult to transport large quantities of inert gas to the work site (such as in pipelines), or the wind blows the shielding gas away from the arc. In addition, the use of vapor extraction systems has increased in recent years. While these systems remove fumes, they also exhaust the shielding gas if they are placed too close to the welding process.

Among the benefits of the present invention is the ability to use minimal amounts or no inert gas in welding. Alternatively, embodiments of the present invention allow the use of shielding gases that normally could not be used for a particular welding operation. This will be discussed below.

When welding typical (non-coated) workpieces with an arc welding process, shielding of whatever kind is required. It has been discovered that no shielding is required when welding with embodiments of the present invention. That is, no shielding gas, granular flux, and self-shielding electrodes need to be used. However, in contrast to an arc welding process, the present invention produces a quality weld. That is, the above-described welding speeds can be achieved without shielding. This could not be achieved with the arc welding processes of the prior art.

During a typical arc welding process, a molten droplet of the filler wire is transferred by the welding arc from the filler wire to the weld puddle. Without shielding, the entire surface of the droplet is exposed during the transfer to the atmosphere and therefore absorbs nitrogen and oxygen from the atmosphere and releases the nitrogen and oxygen to the weld puddle. That is not desirable.

Because the present invention guides the flux-cored wire to the weld without droplets or similar processes, the flux-cored wire is not exposed to the atmosphere to the same extent. Therefore, in many welding applications, the use of a shield is not required. Therefore, embodiments of the present invention can not only achieve high welding speeds with little or no porosity or spatter, but can do so without using a shielding gas.

Without having to use a shield, it is possible to position a steam extraction nozzle much closer to the welding joint during welding, thus enabling a more efficient and effective extraction of vapors. If a shielding gas is used, it is necessary to place the vapor extraction nozzle in such a location that it does not interfere with the function of the shielding gas. Thanks to the advantages of the present invention There is no such limitation and the extraction of vapors can be optimized. For example, in an exemplary embodiment of the present invention, the laser beam becomes 110 through a laser shield assembly 1901 Protected the beam from the laser 120 close to the surface of the workpiece 115 shields. A representation of this is in 19 to see. The screen 1901 (shown in cross-section) protects the beam 110 against interference and provides additional security during operation. Furthermore, the screen with a vapor extraction system 1903 be coupled, which extracts any welding fumes from the weld zone. Because embodiments without shielding gas can be used, the shield 1901 be positioned very close to the weld to remove the vapors directly from the weld zone. The screen 1901 can be conveniently positioned so that its distance Z over the weld is in the range of 0.125 to 0.5 inches. Of course, other distances can be used, but care must be taken not to disturb the puddle or the effectiveness of the screen 1901 significantly affect. Because steam exhaust systems 1903 are generally understood by the welding expert and known to him, their design and function are not discussed in detail in the present text. Although 19 the screen 1901 so it shows that he only has the beam 110 Of course, it is possible that the screen protects 1901 is built so that it has at least a section of the wire 140 and the contact tip 160 protects. For example, it is possible that the bottom opening of the umbrella 1901 is large enough to cover almost the entire puddle of sweat, or even larger than the sweat puddle, to enhance the extraction of vapors.

In exemplary embodiments of the present invention used to weld coated workpieces, such as galvanized workpieces, a much less expensive shielding gas can be used. For example, a shielding gas consisting of 100% CO ₂ can be used to weld many different materials, such as mild steels. This is true even if more complex metals are welded, such as stainless steel, duplex steel and super duplex steel, which can be welded using only a 100% nitrogen blanket gas. In typical arc welding operations, welding stainless steel, duplex steel or super duplex steel requires more complex shielding gas mixtures, which can be quite expensive. Embodiments of the present invention permit welding of these steels with only a 100% nitrogen blanket gas. In other embodiments, these steels may be welded without shielding. In a typical galvanized material welding process, a specially mixed inert gas, such as an argon / CO ₂ mixture, must be used. This type of gas must be used in part because during normal arc welding, a cathode and an anode are present in the weld zone. However, as explained above and discussed further below, there is no welding arc, and therefore there is neither an anode nor a cathode in the weld zone. Therefore, the risk of the filler metal picking up harmful elements from the atmosphere is significantly reduced since there is no arc or droplet transfer. It should be noted that although many embodiments of the present invention allow welding without shielding - such as inert gas - but still a gas flow over the weld can be used to remove vapors or contaminants from the weld zone. That is, during welding, it is contemplated that air, nitrogen, CO ₂ or other gases may be blown across the weld to remove contaminants from the weld zone.

In addition to the ability to weld coated materials at high speeds, embodiments of the present invention may also be used to weld dual phase steels with a significantly reduced heat affected zone ("HAZ"). A dual-phase steel is a high-strength steel that has both a ferrite and a martensite microstructure, whereby the steel can have high strength and good formability. Due to the nature of dual phase steels, the strength of a dual phase steel weld is limited by the strength of the heat affected zone. The heat affected zone is the zone around the weld joint (other than the filler metal) that is significantly heated by the welding process, such that its microstructure is adversely affected by the arc welding process. In known arc welding processes, the heat affected zone is quite large due to the size of the arc plasma and the high heat input to the weld zone. Because the heat affected zone is quite large, the heat affected zone becomes the strength limiting portion of the weld. Therefore, in arc welding processes usually mild steel filler wires 140 used for welding such joints (for example ER70S-6 or -3 electrodes), since the use of high-strength electrodes is unnecessary. Furthermore, for this reason, the designers must strategically keep the weld joints in dual-phase steels out of highly stressed structures, such as in motor vehicle frames, bumpers, engine mounts, etc.

As discussed above, using the laser device offers 120 a high degree Precision in the generation of the sweat puddle. Thanks to this precision, the heat affected zone surrounding the weld bead can be kept very small, or the overall effect of the heat affected zone on the workpiece can be minimized. In some embodiments, the heat affected zone of the workpiece may even be almost eliminated. This is done by looking at the focus of the laser beam 110 holds only on the sections of the workpiece in which a puddle is to be created. By significantly reducing the size of the heat affected zone, the strength of the base metal is not compromised as much as in the case of using an arc welding process. Therefore, the presence or location of the heat affected zone is no longer the limiting factor in the design of a welded structure. Embodiments of the present invention allow the use of higher strength cored wires because the composition and strength of the workpiece and the strength of the flux cored wire can be the determining factors in structural design rather than the heat affected zone. For example, embodiments of the present invention now permit the use of electrodes having a yield value of at least 80 ksi, such as ER80S-D2 type electrodes. Of course, this electrode should only be exemplary. Furthermore, because there is less overall heat input than arc welding, the puddle cooling rates are faster, which means that the chemical composition of the flux cores used may be leaner but still provide the same or higher performance as existing wires.

Furthermore, exemplary embodiments of the present invention may be used to weld titanium with significantly lower shielding requirements. It is well known that when welding titanium with an arc welding process, great care must be taken to produce an acceptable weld. This is because titanium has a strong affinity to react with oxygen during the welding process. The reaction between titanium and oxygen produces titania that, when present in the weld puddle, significantly reduces the strength and / or ductility of the weld. Because of this, in arc welding titanium, it is necessary to supply a significant amount of lagging shielding gas to protect not only the arc but also the trailing molten puddle from the atmosphere as the puddle cools. Due to the heat generated by arc welding, the weld puddle may be quite large and may remain molten for a long time, requiring a significant amount of shielding gas. Embodiments of the present invention significantly reduce the time that the material is in the molten state and cools rapidly, thus reducing the need for this additional shielding gas.

As explained above, the laser beam 110 be focused very precisely to significantly reduce the total heat input to the weld zone and thus significantly reduce the size of the weld puddle. Because the sweat puddle is smaller, the sweat puddle cools much faster. Therefore, there is no need for a lagging shielding gas, but only for a shield at the weld. Moreover, for similar reasons, as discussed above, the weld spatter factor in titanium welding is significantly reduced as the weld rate is increased.

We turn now to the 7 and 7A to where a weld joint with web spacing is shown. Bar spacing joints are often used to weld thick plates and pipes, and can often be found in remote and challenging locations. There are a number of known methods for welding bar spacing weld joints, such as shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), flux cored arc welding (FCAW), submerged powder Arc welding (SAW) and flux-cored arc welding, self-shielding (FCAW-S). These welding processes have several disadvantages, including the need for shielding, speed restrictions, the formation of slag, etc.

That is, embodiments of the present invention significantly improve the efficiency values and speeds at which these types of welds can be made. More specifically, the use of a shielding gas can be eliminated or significantly reduced, and the generation of slag can be completely eliminated. Furthermore, high speed welding with minimal spatter and porosity formation can be accomplished.

7 and 7A show representative fin-gap welded joints that are welded by exemplary embodiments of the present invention. Of course, embodiments of the present invention may be used to weld a wide variety of welds; not only for overlap joints or welding joints with bar spacing. In 7 is a gap 705 between the workpieces W1 / W2, and each respective workpiece has an angled surface 701 / 703 , As discussed above, embodiments of the present invention utilize a laser device 120 to create a precise one Melt puddle on the surfaces 701 / 703 and a preheated filler wire (not shown) is deposited in the respective puddles as described above.

Exemplary embodiments of the present invention are not limited to directing a single flux cored wire to each respective weld puddle. Because no welding arc is generated in the welding process described herein, multiple cored wires can be directed to each individual weld puddle. By increasing the number of cored wires to a given weld puddle, the overall deposition rate of the welding process can be significantly increased without the heat input significantly increasing. Therefore, it is considered that joints with web spacing (such as of the type used in the 7 and 7A shown) can be filled in a single welding pass.

In addition, as in 7 In some exemplary embodiments of the present invention, multiple laser beams may be shown 110 and 110A used to melt multiple locations in the weld joint simultaneously. This can be done in different ways. In a first embodiment, in 7 shown, becomes a beam splitter 121 used and with the laser device 120 coupled. A beam splitter 121 is known to those skilled in the field of laser devices and need not be discussed in detail herein. The beam splitter 121 splits the beam from the laser device 120 into two (or more) separate rays 110 / 110A and can direct it to two different surfaces. In such an embodiment, multiple surfaces can be irradiated simultaneously, making welding even more precise and accurate. In a further embodiment, each of the separate beams 110 and 110A be generated by a separate laser device so that each beam is sent from its own dedicated device.

In such an embodiment, which employs multiple laser devices, many aspects of the welding operation can be varied to accommodate different welding requirements. For example, the beams generated by the separate laser devices may have different energy densities, different shapes, and / or different cross-sectional areas at the weld joint. With this flexibility, aspects of the welding process can be modified and customized to realize all the special welding parameters required. Of course, this can also be done with the help of a single laser device and a beam splitter 121 can be achieved, but using a single laser source can limit some of the flexibility. Moreover, the present invention is not limited to either a single or a dual laser configuration, since it is contemplated that any number of lasers may be used as desired.

In other exemplary embodiments, a beam scanning apparatus may be used. Such devices are known to those skilled in the art of lasers or laser beams and are used to control the beam 110 to guide in a pattern over a surface of the workpiece. With such devices, the scan rates and patterns as well as the dwell time can be used for the workpiece 115 to heat in the desired way. In addition, the output power of the energy source (for example, the laser) can be controlled as needed to achieve the desired puddling. Furthermore, the inside of the laser 120 optics are optimized on the basis of the desired operating and joint parameters. For example, line and integrator optics can be used to use a focused line beam for a wide welding or plating operation, or an integrator can be used to produce a square or rectangular beam having a uniform power distribution.

7A shows a further embodiment of the present invention, where a single beam 110 is directed to the weld joint with open bridge to the surfaces 701 / 703 to melt.

Due to the precision of the laser beams 110 and 110A can the rays 110 / 110A only on the surfaces 701 / 703 and from the gap 705 be focused on. Because of this, the melting through (normally through the gap 705 which would control the rear weld bead (the weld bead at the bottom of the gap 705 ) clearly improved.

In each of the 7 and 7A there is a gap 705 between the workpieces W1 and W2, with a welding bead 707 is filled. In an exemplary embodiment, this weld bead becomes 705 generated by a laser device (not shown). For example, during a welding operation, a first laser device (not shown) directs a first laser beam (not shown) onto the gap 705 to the workpieces W1 and W2 by means of the laser welding bead 707 to weld while the second laser device 120 at least one laser beam 110 / 110A on the surfaces 701 / 703 directed to form weld puddles where one or more cored wires (not shown) are deposited to complete the weld. The splitting weld bead 707 can alone by means of a laser can be generated when the gap is small enough, or can be generated by means of a laser and a filler wire when the gap 705 it requires. Specifically, it may be necessary to add filler metal to the gap 705 to fill properly so that a cored wire should be used. The production of this caterpillar 705 is similar to that described above with respect to various exemplary embodiments of the present invention.

It should be noted that the high-intensity energy sources, such as the laser devices discussed herein 120 should be of a type that has enough power to provide the necessary energy density for the desired welding operation. That is, the laser device 120 should have enough energy to create and maintain a stable weld puddle throughout the welding process, and also to achieve the desired penetration. For example, lasers for some applications should have the ability to form a "keyhole" in the welded workpieces. This means that the laser should have enough energy to realize a full burn in the workpiece while maintaining that burn-in depth as the laser moves along the workpiece. Exemplary lasers should have power capacities in the range of 1 to 20 kW and may have a power capacity in the range of 5 to 20 kW. Powerful lasers can also be used, but these can be very expensive. Of course, it should be noted that the beam splitter 121 or multiple lasers can be used in other types of welds, and can be used for example in overlap joints, such as those in the 6 and 6A are shown.

7B shows another exemplary embodiment of the present invention. In this embodiment, a narrow groove, deep weld with open web is shown. When arc welding deep joints (deeper than 1 inch), it may be difficult to weld the bottom of the joint if the gap G for the groove is narrow. This is because it is difficult to effectively direct shielding gas into such a deep groove, and that the narrow walls of the groove may affect the stability of a welding arc. Because the workpiece is typically an iron material, the walls of the joint may magnetically disturb the welding arc. Therefore, in the case of typical arc welding methods, the gap G of the groove must be sufficiently wide so that the arc remains stable. However, the wider the groove, the more filler metal is required to complete the weld. Because embodiments of the present invention do not require shielding gas and do not use a welding arc, this problem is minimized. Thereby, embodiments of the present invention can efficiently and effectively weld deep, narrow grooves. For example, in an exemplary embodiment of the present invention, the workpiece 115 has a thickness of more than 1 inch, the gap width G is in the range of 1.5 to 2 times the diameter of the filler wire 140 , and the side wall angle is in the range of 0.5 to 10 degrees. In an exemplary embodiment, the caterpillar penetration of such a weld may have a gap RG in the range of 1 to 3 mm with a land flank in the range of 1/16 to 1/4 inch. That is, deep butted joints can be welded faster and with much less filler material than in normal arc welding processes. Moreover, because aspects of the present invention introduce much less heat into the weld zone, the tip can 160 be designed so that a much closer feeding to the welding puddle is possible to avoid contact with the side wall. That is, the top 160 can be made smaller and can be designed as an insulated guide with a narrow structure. In another exemplary embodiment, a translation device or translation mechanism may be used to move the laser and wire across the width of the weld to weld both sides of the joint simultaneously.

As in 8th a butt joint may be welded with embodiments of the present invention. In 8th a flush butt joint is shown; however, it is contemplated that butt joints with V notches on the top and bottom surfaces of the weld joint can also be welded. In the in 8th shown embodiment are two laser devices 120 and 120A shown on each side of the weld, each with its own puddle of sweat 801 and 803 produce. As in the 7 and 7A , the heated cored wires are not shown, as they are the laser beams 110 / 110A hurry in the view shown.

When welding butt joints with known arc technology, there may be significant problems with "arc deflection" that occurs when the magnetic fields generated by welding arcs interfere with each other so that the arcs cause each other to jump. Moreover, when two or more arc welding systems are used for welding at the same weld joint, there can be significant problems caused by the interference of the respective welding currents. Furthermore, the thickness of the workpieces, which can be welded with arcs on each side of the weld joint, due in part to the penetration depth of arc welding due to the high heat input is limited. That is, such welding can not be performed on thin workpieces.

When welding with embodiments of the present invention, these problems are eliminated. Because no welding arc is used, there are no problems with arc deflection interference or welding current interference. In addition, due to the precise control of the heat input and the penetration depth, the use of lasers allows much thinner workpieces to be welded simultaneously on both sides of the weld joint.

Another exemplary embodiment of the present invention is in 9 shown. In this embodiment, two laser beams are connected in series 110 and 110A used to form a unique weld profile. In the embodiment shown, a first beam 110 (from a first laser device 120 emitted) to a first portion of a weld puddle 901 to produce, which has a first cross-sectional area and depth, while the second beam 110A (emitted by a second laser device - not shown) is used to form a second portion of a weld puddle 903 having a second cross-sectional area and depth different from the first one. This embodiment can be used when it is desirable to have a portion of the weld bead that has a greater burn-in depth than the remainder of the weld bead. For example, as in 9 shown is the puddle 901 deeper and narrower than the sweat puddle 903 which is wider and flatter. Such an embodiment may be used where deep penetration is required where the workpieces meet but are not desired for the entire section of the weld joint.

In another exemplary embodiment of the present invention, the first puddle 903 the weld puddle that creates the weld for the joint. This first puddle or fugue comes with a first laser 120 and a flux cored wire (not shown), and is manufactured to an appropriate penetration depth. After this weld has been made, a second laser (not shown), which is a second laser beam 110A sent out, across the fugue, to a second puddle 903 with a different profile, this second puddle being used to deposit a coating material of some sort as discussed in the embodiments described above. This application material is deposited using a second flux-cored wire having a different chemical composition than the first flux-cored wire. For example, embodiments of this invention may be used to apply a corrosion resistant plating layer over the weld joint just or immediately after welding the joint. This welding operation can also be done by means of a single laser device 120 be accomplished, the beam 110 is oscillated between a first beam shape / density and a second beam shape / density to obtain the desired weld puddle profile. That is, it is not necessary to use multiple laser devices.

As discussed above, a corrosion resistant coating on the workpieces (such as a galvanization) is removed during the welding process. However, it may be desirable to re-coat the weld joint for corrosion resistance purposes, and so may the second jet 110A and the laser used for a corrosion-resistant application material 903 , such as a plating layer, on the joint 901 applied.

Due to the various advantages of the present invention, it is also possible to easily join dissimilar metals by means of a welding operation. Bonding dissimilar metals by means of an arc welding process is difficult because the dissimilar materials and the requisite chemical compositions for a filler can cause lead wires to crack and poorly weld. This is especially true when attempting to weld aluminum and steel by means of electric arc welding, which have very different melting temperatures, or when trying to weld stainless steels to mild steel because their chemical compositions are so different. However, embodiments of the present invention mitigate such problems.

10 shows an exemplary embodiment of this invention. Although a V-joint is shown, there is no limitation to the present invention in this regard. In 10 There are two dissimilar metals attached to a weld joint 1000 get connected. In this example, the two dissimilar metals are aluminum and steel. In this exemplary embodiment, two different laser sources are used 1010 and 1020 used. However, two laser devices are not required in all embodiments because a single device can be oscillated to provide the necessary energy to melt the two different materials; this will be discussed below. The laser 1010 sends the beam 1011 which is aimed at the steel workpiece and the laser 1020 sends the beam 1021 on the aluminum workpiece. Because each of the respective workpieces is made of different metals or alloys, they have different ones Melting temperatures. That's why everyone has their own laser beams 1011 / 1021 different energy densities at the welding puddles 1012 and 1022 , Due to the different energy densities, each of the respective welding puddles can 1012 and 1022 be kept at the right size and depth. This also prevents excessive burn-in and excessive heat input to the lower melting temperature workpiece, for example, aluminum. In some embodiments, it is not necessary, at least because of the weld joint, to have two separate, discrete puddles (as in FIG 10 shown); rather, a single weld puddle may be formed with both workpieces, with the molten portions of each of the workpieces forming a single weld puddle. Moreover, when the workpieces have different chemical compositions but similar melting temperatures, it is possible to use a single beam to simultaneously irradiate both workpieces, with the understanding that one workpiece melts more than the other. Moreover, as briefly described above, it is possible to use a single energy source (such as the laser device 120 ) to irradiate both workpieces. For example, a laser device could 120 use a first beam shape and / or energy density to melt the first workpiece and then oscillate or change to a second beam shape and / or energy density to melt the second workpiece. The oscillation and changing of the beam characteristics should be accomplished at a sufficient rate to ensure that the proper melting of both workpieces is maintained so that the one or more weld puddles are kept stable and uniform throughout the welding process. Other single-beam embodiments may include a beam 110 use, which has a shape that performs a higher heat input to a workpiece than to the other, to ensure a sufficient melting of each workpiece. In such embodiments, the energy density of the beam may be uniform for the cross section of the beam. For example, the beam 110 have a trapezoidal or triangular shape, so that the total heat input to a workpiece is less than to the other workpiece due to the shape of the beam. Alternatively, some embodiments may include a beam 110 use, which has a non-uniform energy distribution in its cross section. For example, the beam 110 have a rectangular shape (so that it meets both workpieces), but a first region of the beam has a first energy density, and a second region of the beam 110 has a second energy density, which differs from the energy density of the first region, so that each of the regions can appropriately melt the respective workpieces. As an example, the beam 110 a first region having a high energy density for melting a steel workpiece, while the second region has a lower energy density for melting an aluminum workpiece.

In 10 are two cored wires 1030 and 1030A shown pointing to a sweat puddle 1012 respectively. 1022 are directed. Although the in 10 As shown in the embodiment shown using two cored wires, there is no limit to the present invention in this regard. As discussed above with respect to other embodiments, it is contemplated that depending on the desired welding parameters, such as desired bead shape and deposition rate, only a single flux-cored wire may be used or that more than two wires may be used. If a single wire is used, it may either be directed to a common puddle (formed from the molten portions of both workpieces), or the wire need only be directed at one of the molten portions to be integrated into the weld , So, for example, in the in 10 shown embodiment, a wire on the melted portion 1022 be directed, which then melted with the section 1012 combined to form the weld joint. Of course, if a single wire is used, it should be heated to a temperature that allows the wire in the section 1022 / 1012 melts into which he is immersed.

Because dissimilar metals are joined, the chemical composition of the flux cored wires must be chosen to ensure that the wires can adequately bond to the metals being joined. Furthermore, the composition of the one or more cored wires must be selected to have an appropriate melting temperature that allows them to be melted and consumed in the lower temperature weld puddle. It is contemplated that the chemical compositions of the plurality of cored wires may be different to obtain the proper chemical composition of the weld. This is especially the case when the two different workpieces have material compositions that cause minimal mixing between the materials. In 10 The sweat puddle with the lower temperature is the aluminum sweat puddle 1012 , and thus the one or more cored wires 1030 (A) formulated so that they melt at a similar temperature, allowing them to easily in the puddle 1012 can be consumed. In the above example, using aluminum and steel workpieces, the cored wires may be on silicon bronze, nickel aluminum bronze, or aluminum bronze based wire, which has a similar melting temperature as the workpiece. Of course, it is contemplated that the cored wire compositions are selected to be tuned to the desired mechanical and welding performance characteristics while at the same time providing melt characteristics similar to those of the at least one of the workpieces to be welded.

The 11A to 11C show different embodiments of the tip 160 that can be used. 11A shows a tip 160 which closely resembles the structure and operation of a normal arc welding contact tip. During hot wire welding, as described herein, the heating current is from the power supply 170 to the contact point 160 headed and gets from the top 160 in the wire 140 directed. The current is then transmitted through the wire to the workpiece via the contact of the wire 140 directed to the workpiece W. This current flow heats the wire 140 as described herein. Of course, the power supply needs 170 not directly coupled to the contact tip, as shown, but may be with a wire feeder 150 be coupled, which is the current to the top 160 passes. 11B shows a further embodiment of the present invention, wherein the tip 160 from two components 160 and 160 ' so that the negative terminal of the power supply 170 with the second component 160 ' is coupled. In such an embodiment, the heating current flows from the first peak component 160 to the wire 140 and then into the second peak components 160 ' , The flow of current through the wire 140 , between the components 160 and 160 ' , causes heating of the wire as described herein. 11C shows another exemplary embodiment, wherein the tip 160 an induction coil 1110 contains that causes the tip 160 and the wire 140 be heated by induction heating. In such an embodiment, the induction coil 1110 integral with the contact tip 160 be formed, or they may be around a surface of the top 160 to be wound around. Of course, other configurations may also be for the top 160 can be used as long as the tip the required heating current or the required power to the wire 140 so that the wire can reach the desired temperature for the welding operation.

The operation of exemplary embodiments of the present invention will now be described. As discussed above, embodiments of the present invention use both a high-intensity power source and a power supply that heats the flux-cored wire. Every aspect of this process is discussed in turn. It should be understood that the following descriptions and discussions are not intended to replace any of the discussions given above with respect to the build-up weld embodiments discussed above, but are intended to supplement those relating to welding or bonding applications. The above discussions regarding the hardfacing operations are also included for the purposes of joining and welding.

Exemplary embodiments for joining and welding may be similar to those described in US Pat 1 are shown. As described above, a hot wire power supply 170 provided a heating current to the filler wire 140 supplies. The current flows from the contact tip 160 (which may be of any known type) to the wire 140 and then into the workpiece. This resistance heating current causes the wire 140 between the top 160 and the workpiece at a temperature at or near the melting temperature of the filler wire used 140 reached. Of course, the melting temperature of the filler wire varies 140 depending on the size and chemical composition of the wire 140 , Accordingly, the desired temperature of the filler wire during welding varies depending on the wire 140 , As will be discussed in more detail below, the desired operating temperature for the flux-cored wire may be data input to the welding system such that the desired wire temperature is maintained during welding. In any case, the temperature of the wire should be chosen so that the wire is consumed in the weld puddle during the welding operation. In exemplary embodiments, at least a portion of the filler wire is 140 when the wire enters the weld puddle. For example, at least 30% of the filler wire is solid when the filler wire enters the weld puddle.

In an exemplary embodiment of the present invention, the hot wire power supply holds 170 at least part of the filler wire at a temperature which is at or above 75% of its melting temperature. If, for example, a mild steel filler wire 140 is used, the temperature of the wire before it enters the puddle may be about 1,600 ° F while the wire has a melting temperature of about 2,000 ° F. Of course, it is understood that the particular melting temperatures and desired operating temperatures vary at least according to the alloy, the composition, the diameter and the feed rate of the filler wire. In another exemplary embodiment, the power supply stops 170 a portion of the cored wire at a temperature at or above 90% of its melting temperature. In further exemplary embodiments, portions of the wire are maintained at a temperature of the wire that is at or above 95% of its melting temperature. In exemplary embodiments, the wire has 140 a temperature gradient from the point where the heating current in the wire 140 and the puddle is applied, wherein the temperature in the puddle is higher than that at the entry point of the heating stream. It is desirable to have the warmest temperature of the wire 140 at or near the point where the wire enters the puddle to efficiently melt the wire 140 to enable. That is, the above-indicated temperature percentages are to be measured on the wire at or near the point where the wires enter the puddle. By holding the filler wire 140 at a temperature near or at its melting temperature becomes the wire 140 in a simple way in by the heat source or the laser 120 melted puddle melted or consumed in it. That is, the wire 140 is at a temperature that does not lead to a significant quenching of the weld puddle when the wire 140 makes contact with the puddle. Due to the high temperature of the wire 140 The wire quickly melts when it makes contact with the welding puddle. It is desirable to set the wire temperature so that the wire does not touch the bottom of the weld puddle, ie, does not make contact with the unmelted portion of the weld puddle. Such contact can adversely affect the quality of the weld

As previously described, in some example embodiments, the complete melting of the wire 140 only by the entry of the wire 140 be done in the puddle. However, the wire can 140 in other exemplary embodiments also by a combination of the puddle and the laser beam 110 that is on a part of the wire 140 hits, completely melted. In still other embodiments of the present invention, the heating or melting of the wire 140 through the laser beam 110 be supported in such a way that the beam 110 for heating the wire 140 contributes. Because, however, many cored wires 140 made of materials that can reflect should, if a reflective laser is used, the wire 140 be heated to a temperature such that its surface reflectivity is reduced, so that the beam 110 for heating or melting the wire 140 can contribute. In exemplary embodiments of this configuration, the wire overlap 140 and the beam 110 at the point where the wire 140 enters the puddle.

As before with reference to 1 discussed, control the power supply 170 and the control unit 195 the heating current to the wire 140 such that during welding the wire 140 keeps the contact to the workpiece and no arc is generated. In contrast to welding technology, the presence of an arc during welding with embodiments of the present invention can lead to significant defects in the weld. That is, in some embodiments (such as those discussed above), the tension between the wire should be 140 and maintaining the weld puddle at or near zero volts, indicating that the wire is shorted or in contact with the workpiece or weld puddle.

However, in other exemplary embodiments of the present invention, it is possible to provide a current at a level such that a voltage level above 0 volts is obtained without generating an arc. By using higher current values, it is possible to use the electrode 140 at temperatures at a higher level and closer to the melting temperature of an electrode. This makes the welding process faster. In exemplary embodiments of the present invention monitors the power supply 170 the voltage, and when the voltage reaches or approaches a voltage at a point above 0 volts, the power supply stops 170 feeding electricity into the wire 140 to ensure that no arc is generated. The threshold voltage level typically varies, at least in part, according to the type of welding electrode used 140 , For example, in some exemplary embodiments of the present invention, the threshold voltage level is at or below 6 volts. In another exemplary embodiment, the threshold level is at or below 9 volts. In another exemplary embodiment, the threshold level is at or below 14 volts, and in another exemplary embodiment, the threshold level is at or below 16 volts. For example, if mild steel cored wires are used, the threshold level for the voltage is of the lower type, while cored wires designed for stainless steel welding can handle higher voltage before an arc is generated.

In other exemplary embodiments, rather than maintaining a voltage level below a threshold, as described above, the voltage is maintained in an operating range. In such an embodiment, it is desirable to maintain the voltage above a minimum amount that ensures a current that is sufficiently high to maintain the filler wire at or near its melting temperature, but below a voltage level so that no welding arc is generated. For example, the voltage in a range of 1 to 16 volts. In another exemplary embodiment, the voltage is maintained in a range of 6 to 9 volts. In another example, the voltage may be maintained between 12 and 16 volts. Of course, the desired operating range can be achieved by the cored wire used for the welding operation 140 so that an area (or threshold) used for a welding operation is selected, at least in part, based on the filler wire used or on the characteristics of the flux-cored wire used. In using such a range, the lower end of the range is set to a voltage at which the filler wire can be sufficiently consumed in the weld puddle, and the upper limit of the range is set to such a voltage as to avoid generation of an arc.

As described above, when the voltage exceeds a desired threshold voltage, the heating current through the power supply becomes 170 switched off, so that no arc is generated. This aspect of the present invention will be discussed below.

In the many embodiments described above, the power supply includes 170 Circuits used to monitor and hold the voltage as described above. The construction of such types of circuits is known to those skilled in the art. However, such circuits have conventionally been used to maintain a voltage above a certain threshold for arc welding.

In further exemplary embodiments, the heating current may also be provided by the power supply 170 monitored and / or regulated. This may alternatively be done in addition to monitoring voltage, power, or a level of a voltage or current characteristic. That is, the current can be kept at one or more desired levels to ensure that the wire 140 is maintained at an appropriate temperature for proper wicking in the weld puddle, yet below an arc generation current level. For example, in such an embodiment, the voltage and / or current is monitored to ensure that one or both are within a specified range or below a desired threshold. The power supply then regulates the supplied current to ensure that no arc is generated but the desired operating parameters are maintained.

In another exemplary embodiment of the present invention, the heating power (V x I) may also be provided by the power supply 170 be monitored and regulated. More specifically, in such embodiments, the voltage and current for the heating power are monitored to be maintained at a desired level or within a desired range. That is, the power supply not only controls the voltage or current to the wire, but it can control both the current and the voltage. Such an embodiment may allow for improved control over the welding system. In such embodiments, the heating power to the wire may be set to an upper threshold level or operating range such that the power is to be maintained below either the threshold level or within the desired range (similar to what has been discussed above with respect to voltage). , Again, the threshold or range adjustments are based on the characteristics of the filler wire and the welding performed and may be based, at least in part, on the selected flux cored wire. For example, it may be determined that an optimum power setting for a 0.045 "diameter mild steel electrode is in the range of 1950 to 2050 watts. The power supply regulates the voltage and current so that the power remains in this operating range. Likewise, if the power threshold is set to 2000 watts, the power supply can regulate the voltage and current so that the power level does not exceed this threshold, but is close to it.

In other exemplary embodiments of the present invention, the power supply includes 170 Circuits that monitor the rate of change of the heating voltage (dv / dt), the current (di / dt) and / or the power (dp / dt). Such circuits are often referred to as upshift circuits, and their general design is known. In such embodiments, the rate of change of voltage, current, and / or power is monitored so that when the rate of change exceeds a certain threshold, the heating current to the wire 140 is switched off.

In an exemplary embodiment of the present invention, the change in resistance (dr / dt) is also monitored. In such an embodiment, the resistance in the wire between the contact tip and the puddle is monitored. During welding, the wire begins to pinch off when heated and has a tendency to form an arc; during this time, the resistance in the wire increases exponentially. When this increase is detected, the output of the power supply becomes shut down as described herein to ensure that no arc is generated. Embodiments control the voltage, current, or both to ensure that the resistance in the wire is maintained at a desired level.

In further exemplary embodiments of the present invention, the heating current is not turned off when the threshold level is detected, but the power supply 170 reduces the heating current to a non-arc generation level. Such a level may be a background current level where no arc is generated when the wire is separated from the weld puddle. For example, an exemplary embodiment of the present invention may have a non-arcing current level of 50A where, once arc generation is detected or predicted or reaches an upper threshold (discussed above), the power supply 170 the heating current from its operating level to the non-arcing level either for the duration of a predetermined period of time (eg, 1 to 10 ms), or until the detected voltage, the detected current, the detected power, and / or the detected resistance is below the upper threshold falls, lowers. This non-arc generation threshold may be a voltage level, a current level, a resistance level, and / or a power level. In such embodiments, by maintaining a current output during an arcing event, albeit at a low level, a faster return to the heating current operating level may be performed.

In another exemplary embodiment of the present invention, the output of the power supply 170 controlled so that no appreciable arc is generated during the welding operation. In some exemplary welding operations, the power supply can be controlled so that there is no appreciable arc between the flux cored wire 140 and the puddle is created. It is well known that an arc between a physical gap between the distal end of the filler wire 140 and the weld puddle is generated. As described above, exemplary embodiments of the present invention prevent such arcing by causing the filler wire 140 kept in contact with the puddle. However, in some exemplary embodiments, the presence of a negligible arc does not affect the quality of the weld. That is, in some exemplary welding operations, the creation of a negligible short duration arc does not result in a degree of heat input that affects weld quality. In such embodiments, the welding system and power supply are controlled and operated as described herein with respect to the complete elimination of an arc, but the power supply 170 is controlled so that, insofar as an arc is generated, the arc is insignificant. In some example embodiments, the power supply becomes 170 operated so that a generated arc has a duration of less than 10 ms. In other exemplary embodiments, the arc has a duration of less than 1 ms, and in other exemplary embodiments, the arc has a duration of less than 300 μs. In such embodiments, the presence of such arcs does not affect weld quality because the arc does not cause significant heat input to the weld, or cause significant spatter or significant porosity. That is, in such embodiments, the power supply becomes 170 controlled so that, insofar as an arc is generated, it is kept to a negligible duration, so that the weld quality is not affected. The same control logic and control components as those discussed herein with respect to other embodiments may be used in these exemplary embodiments. However, the power supply can 170 for the upper threshold limit, use the detection of arc generation, rather than a threshold point (of current, power, voltage, resistance) below a predetermined or predicted arc creation point. Such an embodiment may allow the welding operation to operate closer to its limits.

Because it is desired that the filler wire 140 In a constantly shorted condition (in constant contact with the weld puddle), the current tends to decay at a slow rate. This is due to the inductance present in the power supply, the welding cables and in the workpiece. In some applications, it may be necessary to force the current to decay at a faster rate so that the current in the wire is reduced at a high rate. In general, the faster the power can be reduced, the better the control that can be achieved via a connection method. In an exemplary embodiment of the present invention, the time-out for the current after detecting reaching or exceeding a threshold is 1 millisecond. In another exemplary embodiment of the present invention, the time-to-go for the current is 300 microseconds or less. In a further exemplary embodiment, the Descent time in the range of 300 to 100 microseconds.

In an exemplary embodiment, to achieve such descent times, a descent circuit is incorporated into the power supply 170 which helps shorten the descent time when an arc is predicted or detected. For example, when an arc is either detected or predicted, a descent circuit opens, introducing resistance into the circuit. For example, the resistance may be of a type that reduces the current flow to below 50A in 50 microseconds. A simplified example of such a circuit is in 18 shown. The circuit 1800 has a resistance 1801 and a switch 1803 , which are built into the welding circuit so that when the power supply is working and supplying power, the switch 1803 closed is. However, if the power supply stops the power supply (to prevent the generation of an arc or if an arc is detected), the switch opens and forces the induced current through the resistor 1801 , The resistance 1801 significantly increases the resistance of the circuit and reduces the current at a faster pace. Such type of circuit is the welding expert generally known and can be found for example in a Powerwave ^® -Schweißstromversorgung which is manufactured by The Lincoln Electric Company of Cleveland, Ohio and the Surface Tension Transfer technology ( "STT") contains. The STT technology is commonly used in U.S. Patent Nos. 4,866,247 . 5,148,001 . 6,051,810 and 7,109,439 which are hereby incorporated by reference in their entireties in the present text. Of course, these patents generally discuss the use of the disclosed circuits to ensure that an arc is created and maintained. Those skilled in the art can easily adapt such a system to ensure that no arc is generated.

The discussion described above may be with reference to 12 be further understood, where an exemplary welding system is shown. (It should be noted that the laser system 13 not shown for clarity). The system 1200 is shown to be a hot wire power supply 1210 (which may be of a similar type to the one referred to as 170 in 1 is shown). The power supply 1210 may be of a known welding power supply type, such as an inverter power supply. Because the design, operation and construction of such power supplies are known, they are not discussed in detail herein. The power supply 1210 contains a user input 1220 allowing a user to enter data including, for example, wire feed rate, wire type, wire diameter, desired power level, desired wire temperature, or desired voltage and / or current level. Of course, other input parameters may be used as needed. The user interface 1220 is with a CPU or control unit 1230 which receives the user input data and uses this information to obtain the required operating setpoints or ranges for the power module 1250 to create. The energy module 1250 may be of any known type or construction, including an inverter or transformer module.

The CPU or control unit 1230 can determine the desired operating parameters in a number of different ways, including using a look-up table. In such an embodiment, the CPU or control unit uses 1230 the input data, for example wire feed rate, wire diameter and wire type, to determine the desired current level for the output (around the wire 140 to heat suitably) and the threshold voltage or power level (or acceptable operating range of voltage or power). The reason is that the power needed to heat the wire 140 based on the appropriate temperature at least on the input parameters. That is, an aluminum wire 140 may have a lower melting temperature than a mild steel electrode and thus requires less power or energy to the wire 140 to melt. It also requires a wire 140 smaller diameter less power or energy than a larger diameter electrode. In addition, with increasing wire feed rate (and correspondingly higher deposition rate), the power or power level needed to melt the wire also increases.

Likewise, the input data is provided by the CPU or control unit 1230 used to determine the voltage or power thresholds and / or ranges (eg, power, current, and / or voltage) for operation such that the generation of an arc is avoided. For example, for a 0.045 inch diameter mild steel electrode, a voltage range setting may be 6 to 9 volts, with the energy modulus 1250 is controlled so that the voltage between 6 and 9 volts is maintained. In such an embodiment, current, voltage and / or power are controlled to maintain a minimum of 6 volts, which ensures that the current or power is sufficiently high to properly heat the electrode, and the voltage is up or down 9 volts to ensure that no arc is generated and that a melting temperature of the wire 140 is not exceeded. Of course, other set point parameters, such as voltage, current, power, or resistance rate changes, may be changed by the CPU or controller as needed 1230 be set.

As shown, is a positive connection 1221 the power supply 1210 with the contact tip 160 of the hot wire system, and a negative terminal of the power supply is coupled to the workpiece W. That is, a heating current is passed through the positive terminal 1221 to the wire 140 passed and through the negative connection 1222 recycled. Such a configuration is well known.

Of course, in another exemplary embodiment, the negative terminal may be 1222 also with the top 160 be connected. Because resistance heating for heating the wire 140 can be used, the top of a construction (as in the 11 shown), where both the negative and the positive connection 1221 / 1222 with the contact tip 140 can be coupled to the wire 140 to warm up. For example, the contact tip 160 a dual construction (as in 11B shown) or an induction coil (as in 11C shown).

A feedback sense connection wire 1223 is also connected to the power supply 1210 coupled. This feedback sense lead can monitor the voltage and the detected voltage into a voltage detection circuit 1240 feed. The voltage detection circuit 1240 transmits the detected voltage and / or the detected voltage change rate to the CPU or control unit 1230 that the operation of the module 1250 controls accordingly. For example, if the detected voltage is below a desired operating range, the CPU or controller will instruct 1230 the module 1250 to increase its output (current, voltage and / or power) until the detected voltage is within the desired operating range. Equally instructs the CPU or control unit 1230 if the detected voltage is at or above a desired threshold, the module 1250 , the flow of current to the top 160 shut down so that no arc is generated. When the voltage falls below the desired threshold, the CPU or control unit instructs 1230 the module 1250 to supply a current or voltage, or both, to continue the welding process. Of course, the CPU or control unit 1230 the module 1250 also instruct to maintain or deliver a desired level of power.

It should be noted that the detection circuit 1240 and the CPU or control unit 1230 a similar construction and operation as the in 1 shown control unit 195 can have. In exemplary embodiments of the present invention, the sampling or detection rate is at least 10 kHz. In other exemplary embodiments, the sampling or detection rate is in the range of 100 to 200 kHz.

The 13A C show exemplary current and voltage waveforms used in embodiments of the present invention. Each of these waveforms is discussed in turn. 13A shows the voltage and current waveforms for an embodiment where the flux-cored wire 140 the weld puddle touches after the power supply output is turned back on - after an arc detection event. As shown, the output voltage of the power supply is at an operating level below a certain threshold (9 volts) and then rises to that threshold during welding. The operating level may be a particular level based on various input parameters (previously discussed) and may be a set operating voltage, current and / or power level. This operating level is the desired output of the power supply 170 for a given welding process and intended the desired heating signal to the flux-cored wire 140 to transfer. During welding, an event may occur that may cause an arc to occur. In 13A At point A, the power supply or control circuits reach the 9 volt threshold (which may be an arc detection point or simply a predetermined upper threshold which may be below an arc creation point) and switch the output of the power supply, whereby the current and the voltage fall to a reduced level at point B. The slope of the current drop can be controlled by the inclusion of a descent circuit (as discussed herein), which helps to rapidly reduce the current resulting from the system inductance. The current or voltage levels at point B may be predetermined or may be reached after a predetermined period of time. For example, in some embodiments, not only is an upper threshold for the voltage (or current or power) set for welding, but also a lower non-arc generation level. This lower level can either be a lower voltage, current, or power level, ensuring that no arc can be generated, so it is acceptable to turn the power back on without generating an arc becomes. Having such a lower level allows the power supply to quickly turn back on and ensure that no arc is generated. For example, if a power set point for welding is set to 2,000 watts, with a voltage threshold of 11 volts, this lower power setting can be set to 500 watts. That is, when the upper voltage threshold (which may also be a current or power threshold, depending on the embodiment) is reached, the output is reduced to 500 watts. (This lower threshold may also be a lower current or voltage setting, or both.) Alternatively, instead of setting a lower detection limit, a timing loop may also be used to turn on the beginning of supplying current after a set period of time. In exemplary embodiments of the present invention, such duration may be in the range of 500 to 1000 ms. In 13A Point C represents the time at which the output returns to the wire 140 is supplied. It should be noted that the delay shown between points B and C may be the result of intentional delay or simply a result of a system delay. At point C, power is again supplied to heat the filler wire. But because the cored wire does not touch the sweat puddle, the voltage increases, but the current does not. At point D, the wire makes contact with the puddle, and the voltage and current are restored to the desired operating level. As shown, the voltage may exceed the upper threshold before contact at D, which may occur when the power source has an OCV level that is higher than the operating threshold. For example, this higher OCV level may be an upper limit that is set in the power supply during its design or manufacture.

13B is similar to the one described above, except that the cored wire 140 The welding puddle touches when the output of the power supply is increased. In such a situation, either the wire never left the weld puddle or the wire was brought into contact with the weld puddle before point C. 13B shows dots C and D together because the wire is in contact with the puddle when the output is turned back on. Thus, both the current and the voltage at point E increase to the desired operating setting.

13C is an embodiment in which there is at most little delay between turning off the output (point A) and turning the output back on (point B), and where the wire is in contact with the puddle some time before point B. The waveforms shown may be used in embodiments described above in which a lower threshold is set so that when the lower threshold is reached (be it current, power or voltage) the output is turned on again with as little delay as possible. It should be noted that this lower threshold setting may be set by the same or similar parameters as the operational upper thresholds or ranges as described herein. For example, this lower threshold may be set based on wire composition, wire diameter, wire feed speed, or various other parameters described herein. Such an embodiment can minimize the delay in returning to the desired operating set points for welding, and can avoid any pinching that may occur in the wire. Minimizing pinch helps to minimize the risk of arcing.

14 shows another exemplary embodiment of the present invention. 14 shows an embodiment similar to that shown in FIG 1 was shown. However, certain components and connections are not shown for clarity. 14 shows a system 1400 in which a heat sensor 1410 to monitor the temperature of the wire 140 is used. The heat sensor 1410 It can be of any known type used to detect the temperature of the wire 140 is capable. The sensor 1410 can make contact with the wire 140 make or can with the top 160 be coupled to detect the temperature of the wire can. In another exemplary embodiment of the present invention, the sensor is 1410 of a type that uses a laser or infrared beam capable of detecting the temperature of a small object, such as the diameter of a flux cored wire, without the wire 140 to touch. In such an embodiment, the sensor is 1410 positioned so that the temperature of the wire 140 on the board of the wire 140 can be detected; so at a point between the end of the top 160 and the sweat puddle. The sensor 1410 should also be positioned so that the sensor 1410 for the wire 140 does not feel the temperature of the sweat puddle.

The sensor 1410 is with the sensing and control unit 195 (regarding 1 discussed), so that temperature feedback information to the power supply 170 and / or the laser power supply 130 can be transmitted, so that the control of the system 1400 can be optimized. For example, the power or current output of the power supply 170 based on at least the feedback from the sensor 1410 to be adjusted. That is, in one embodiment of the present invention, either the user can set a desired temperature setting (for a particular weld and / or wire 140 ), or the sensing and control unit may set a desired temperature based on other user input data (wire feed speed, electrode type, etc.) and then the sensing and control unit would 195 at least the power supply 170 control so that the desired temperature is maintained.

In such an embodiment, it is possible to heat the wire 140 to take into account, due to the laser beam 110 can come on the wire 140 impinges before the wire enters the weld puddle. In embodiments of the invention, the temperature of the wire 140 only via the power supply 170 be controlled by the current in the wire 140 is controlled. However, in other embodiments, at least a portion of the heating of the wire 140 from the laser beam 110 come on at least part of the wire 140 incident. In that sense, the energy must be from the power supply 170 not alone for the temperature of the wire 140 be representative. Accordingly, the use of the sensor 1410 the regulation of the temperature of the wire 140 by controlling the power supply 170 and / or the laser power supply 130 support.

In a further exemplary embodiment (also in FIG 14 shown) becomes a temperature sensor 1420 instructed to sense the temperature of the weld puddle. In this embodiment, the temperature of the welding puddle also becomes the sensing and control unit 195 coupled. However, the sensor can 1420 in a further exemplary embodiment also directly with the laser power supply 130 be coupled. The feedback from the sensor 1420 is used to control the output of the laser power supply 130 or the laser 120 used. That is, the energy density of the laser beam 110 can be modified to ensure that the desired weld puddle temperature is achieved.

In another exemplary embodiment of the invention, the sensor does not become 1420 It is aimed at an area of the workpiece next to the welding puddle. More specifically, it may be desirable to ensure that the heat input to the workpiece adjacent to the weld is minimized. The sensor 1420 can be positioned to monitor this temperature sensitive area so that a threshold temperature is not exceeded near the weld. For example, the sensor 1420 monitor the workpiece temperature and the energy density of the beam 110 decrease by the sensed temperature. Such a configuration would ensure that the heat input next to the bead would not exceed a desired threshold. Such an embodiment may be used in precision welding operations where heat input into the workpiece is of critical importance.

In another exemplary embodiment of the present invention, the sensing and control unit 195 coupled to a feed force detection unit (not shown) connected to the wire feed mechanism (not shown, but see Figs 150 in 1 ) is coupled. The feed force detection units are known and detect the feed force applied to the wire 140 is applied while the to the workpiece 115 to be led. For example, such a detection unit may monitor the torque produced by a wire feed motor in the wire feeder 150 is created. If the wire 140 As it passes through the molten weld puddle without completely melting, it contacts a fixed portion of the workpiece, and such contact causes the feed force to increase as the motor attempts to maintain a set feed rate. This increase in force or torque can be detected and sent to the controller 195 be forwarded, which uses this information to the voltage, current and / or power to the wire 140 adjust to the correct melting of the wire 140 in the sweat puddle 145 sure.

It should be noted that in some exemplary embodiments of the present invention, the wire is not constantly guided into the weld puddle but may be done intermittently based on a desired weld profile. More specifically, the variety of various embodiments of the present invention allows either an operator or the control unit 195 , feeding the wire 140 to start and stop in the puddle as needed. For example, there are many different types of complex weld profiles and geometries that may include some portions of the weld that involves the use of a filler metal (wire 140 ), and may have other portions of the same joint or on the same workpiece that do not require the use of a filler metal. Therefore, during a first section of a weld, the control unit needs 195 only the laser 120 to cause a laser weld of this first portion of the joint, but if the welding operation reaches a second portion of the weld which requires the use of a filler metal, the control unit will cause 195 the power supply 170 and the wire feeder 150 , the Separating the wire 140 to start in the sweat puddle. Then, when the welding operation reaches the end of the second section, the deposition of the wire may occur 140 being stopped. This allows the formation of continuous welds with a profile that varies significantly from one section to the next. Such capability allows for welding a workpiece in a single welding operation rather than having to use many discrete welding operations. Of course, many variations can be implemented. For example, a weld may have three or more discrete sections that have a weld profile with varying shape, depth and fill material requirements, such that using the laser and the wire 140 may be different in each weld section. Furthermore, additional wires can be added or omitted as needed. That is, a first weld section needs only one laser weld, while a second section requires only a single filler wire 140 requires, and a final section of the weld requires the use of two or more cored wires. The control unit 195 may be enabled to control the various system components to achieve such a varying weld line profile in a continuous welding operation so as to produce a continuous weld bead in a single welding pass.

15 shows a typical welding puddle P in welding in accordance with exemplary embodiments of the present invention. As described above, the laser beam generates 110 the puddle P in the surface of the workpiece W. The weld puddle has a length L which is a function of the energy density, shape and motion of the beam 110 is. In an exemplary embodiment of the present invention, the beam 110 directed at a distance Z from the trailing edge of the welding puddle on the puddle P. In such embodiments, the high-intensity power source (eg, the laser 120 ) that their energy directly on the cored wire 140 impinges, leaving the energy source 120 not the wire 140 melts; rather the wire completes 140 its melting due to its contact with the sweat puddle. The trailing edge of the puddle P may be generally defined as the point where the molten puddle ends and the generated weld bead WB begins to solidify. In one embodiment of the present invention, the distance Z is 50% of the length L of the puddle P. In another exemplary embodiment, the distance Z is in the range of 40 to 75% of the length L of the puddle P.

The filler wire 140 meets the puddle P behind the beam 110 in the feed direction of the weld, as in 15 shown. As shown, the wire hits 140 on the puddle P on a distance X in front of the trailing edge of the puddle P on. In an exemplary embodiment, the distance X is in the range of 20 to 60% of the length of the puddle P. In another exemplary embodiment, the distance X is in the range of 30 to 45% of the length L of the puddle P. In other exemplary embodiments, overlaps the wire 140 and the beam 110 at the surface of the puddle P or at a point above the puddle P, so that at least part of the jet 110 during the welding process on the wire 140 meets. In such an embodiment, the laser beam becomes 110 used for melting the wire 140 to assist in depositing in the puddle P. Using the jet 110 for assisting the melting of the wire 140 Helps to prevent the wire 140 the puddle P deters when the wire 140 too cool to be quickly consumed in the puddle P. However, as previously discussed in some example embodiments (as in FIG 15 shown) cause the energy source 120 and the beam 110 no appreciable melting of sections of the filler wire 140 because the melting is carried out by the heat of the welding puddle.

In the in 15 embodiment shown hurries the wire 140 the beam 110 after and lies on the same line as the beam 110 , However, the present invention is not limited to this configuration because the wire 140 can also precede (in the feed direction). In addition, it is not necessary that the wire 140 is on a line with the beam in the feed direction, but the wire can hit the puddle from any direction as long as there is a suitable melting of the wire in the puddle.

16A to 16F show different puddles P with the base of the laser beam shown 110 , As shown, the puddle P has a circular footprint in some example embodiments. However, embodiments of the invention are not limited to this configuration. For example, it is contemplated that the puddle may also have elliptical or other shapes.

In addition, the beam 110 in the 16A - 16F shown with a circular cross-section. Again, other embodiments of the present invention are not limited in this regard as the beam 110 may have an elliptical, rectangular or other shape to effectively produce a welding puddle P.

In some embodiments, the laser beam 110 remain stationary relative to the welding puddle P. That is, the beam 110 stays in a relatively constant position during welding relative to the puddle P. However, other embodiments are not limited in such a way as exemplified in U.S. Pat 16A - 16D is shown. For example, shows 16A an embodiment where the beam 110 is translated in a circular pattern around the welding puddle P around. In this figure, the beam translates 110 so that at least one point on the beam 110 at any time the middle C of the puddle overlaps. In another embodiment, a circular pattern is used, but the beam 110 does not touch the middle C. 16B shows an embodiment where the beam is translated back and forth along a single line. This embodiment can be used to either lengthen or widen the puddle P depending on the desired shape of the puddle P. 16C shows an embodiment where two different beam cross sections are used. The first beam cross section 110 has a first geometry, and the second beam cross section 110 ' has a second cross section. Such an embodiment may be used to enhance penetration at a point in the puddle P, while maintaining a larger puddle size if necessary. This embodiment may be with a single laser 120 can be accomplished by changing the beam shape using the laser lenses and optics, or it can be done using multiple lasers 120 be accomplished. 16D shows a ray 110 which is translated in an elliptical pattern in the puddle P. Again, such a pattern may be used to either lengthen or widen the weld puddle P as needed. There may be other translations of the beam 110 used to form the puddle P.

16E and 16F show a cross-section of a workpiece W and a puddle P using different beam intensities. 16E shows a shallower broader puddle P, through a wider beam 110 is generated while 16F shows a deeper and narrow sweat puddle P, which is usually referred to as a "keyhole". In this embodiment, the beam is focused so that its focal point is near the top of the workpiece W. With such a focus is the beam 110 being able to penetrate the full depth of the workpiece and to assist in creating a backside bead BB on the underside of the workpiece W. Beam intensity and shape should be determined by the desired properties of the weld puddle during welding.

The laser 120 can be moved, translated or operated by any known methods and devices. Because the motion and optics of lasers are well known, they will not be discussed in detail herein. 17 shows a system 1700 according to an exemplary embodiment of the present invention, wherein the laser 120 can be moved and its optics (such as its lenses) can be changed or adjusted during operation. This system 1700 couples the sensing and control unit 195 both with a motor 1710 as well as with an optics drive unit 1720 , The motor 1710 moves or translates the laser 120 such that the position of the beam 110 is moved relative to the welding puddle during welding. For example, the engine can 1710 the beam 110 translate back and forth, move in a circular pattern, etc. Similarly, the optical drive unit receives 1720 Instructions from the sensing and control unit 195 for controlling the optics of the laser 120 , For example, the optical drive unit 1720 cause the focus of the beam 110 is moved or changed relative to the surface of the workpiece, whereby the penetration or the depth of the weld puddle is changed. Similarly, the optical drive unit 1720 the optics of the laser 120 induce the shape of the beam 110 to change. In this way, the sensing and control unit controls 195 while welding the laser 120 and the beam 110 in order to maintain and / or modify the properties of the weld puddle during operation.

In each of the 1 . 14 and 17 are the laser power supply 130 , the hot-wire power supply 170 and the sensing and control unit 195 shown separately for clarity. However, in embodiments of the invention, these components may be integrally combined in a single welding system. Aspects of the present invention do not require that the components discussed individually above be left as separate physical entities or discrete structures.

As described above, the high-intensity power source may consist of any number of power sources, including welding power sources. An exemplary embodiment of this is in 20 shown a system 2000 similar to the one in 1 shown system 100 shows. Many of the components of the system 2000 are similar to the components in the system 100 why their functioning and application will not be discussed again in detail. However, in the system 2000 the laser system is replaced by an arc welding system, such as a GMAW system. The GMAW system contains a power supply 2130 , a wire feeder 2150 and a burner 2120 , A welding electrode 2110 becomes a molten puddle via the wire feeder 2150 and the burner 2120 supplies. The operation of a GMAW welding system of the type described herein is general known and need not be described in detail in the present text. It should be noted that while a GMAW system is shown and discussed with respect to exemplary embodiments shown, exemplary embodiments of the present invention also include GTAW, FCAW, MCAW and SAW systems, cladding systems, brazing systems, combinations of these systems etc., including those systems that use an arc to assist in the transfer of a consumable to a molten puddle on a workpiece. Not in 20 Shown is a shield gas system or submerged arc arc flux system which may be used in accordance with known methods.

Like the laser systems described above, the arc generation systems (which can be used as the high-intensity energy source) are used to form the molten puddle, which includes the hot wire 140 using systems and embodiments described in detail above. However, it is known that an additional consumable material is also used in the arc generating systems 2110 added to the puddle. This additional consumable increases the already enhanced deposition performance enabled by the hot wire process described herein. This performance will be discussed in more detail below.

In addition, as is well known, arc generation systems, such as GMAW, use high current levels to create an arc between the advancing consumable and the molten puddle on the workpiece. Likewise, GTAW systems use high current levels to create an arc between an electrode and the workpiece to which a consumable is added. As is well known, many different current waveforms may be used for a GTAW or GMAW welding operation, such as constant current, pulsed current, etc. During operation of the system 2000 However, it can be due to the power supply 2130 electricity generated by the power supply 170 generated electricity, used to heat the wire 140 used, obstruct. Because the wire 140 near by the power supply 2130 When the arc is generated (because each of them is directed to the same molten puddle, similar to that described above), the respective currents may interfere with each other. More specifically, each of the currents creates a magnetic field, and these fields can interfere with each other and interfere with their functioning. For example, the magnetic fields generated by the hot wire current can increase the stability of the power supply 2130 affected arc. That is, without proper control and synchronization between the respective currents, the competing magnetic fields can destabilize the arc and thus destabilize the process. Therefore, exemplary embodiments use power synchronization between the power supplies 2130 and 170 to ensure stable operation, which will be discussed below.

21 FIG. 11 shows a closer view of an exemplary welding operation of the present invention. FIG. As you can see, the burner performs 2120 (which may be an exemplary GMAW / MIG torch) consumables 2110 to a weld puddle WP using an arc, as is well known. In addition, the hot-wire consumables 140 guided according to one of the embodiments described above to the welding puddle WP. It should be noted that although the burner 2120 and the top 160 separately shown in this figure, but that these components can also be housed integrally in a single burner unit, both consumables 2110 and 140 leads to the puddle. Of course, if an integral design is used, electrical isolation within the torch must be used to prevent current transfer between the consumables during the process. As mentioned above, magnetic fields induced by the respective currents may interfere with each other so that embodiments of the present invention synchronize the respective currents. The synchronization can be achieved by various methods. For example, the sense and current control unit 195 for controlling the operation of the power supplies 2130 and 170 used to synchronize the streams. Alternatively, a master-slave relationship may be used, with one of the power supplies being used to control the output of the others. The control of the relative currents can be accomplished by a variety of methodologies, including the use of state tables or algorithms that control the power supplies to synchronize their output currents for stable operation. This will be with reference to the 22A -C discussed. For example, a dual-state system and devices similar to those described in U.S. Patent No. 5,729,866 US Patent Publication No. 2010/0096373 described are used. The US Patent Publication No. 2010/0096373 , published on April 22, 2010, is hereby incorporated by reference in its entirety.

Each of the 22A -C shows exemplary current waveforms. 22A shows an exemplary Welding waveform (either GMAW or GTAW), the current pulses 2202 used to transfer droplets from the wire 2110 to assist the puddle. Of course, the waveform shown is exemplary and representative and is not intended to be limiting. For example, the current waveforms may be those for pulsed spray transfer, pulse welding, surface tension transfer welding, and so on. The hot wire power supply 170 gives a current waveform 2203 out, which also has a number of impulses 2204 has to the wire 140 by resistance heating, as generally described above. The current pulses 2204 are separated by a background level with a lower current level. As generally described above, the waveform becomes 2203 for heating the wire 140 used at or near its melting temperature, and uses the pulses 2204 and the background for heating the wire 140 by resistance heating. As in 22A shown are the pulses 2202 and 2204 synchronized by the respective current waveforms so as to be in phase with each other. In this exemplary embodiment, the current waveforms are controlled so that the current pulses 2202 / 2204 have a similar or the same frequency and are in phase with each other as shown. It has been surprisingly discovered that in-phase waveforms produce stable and uniform operation where the arc is not significantly disturbed by the heating current flowing through the waveform 2203 is produced.

22B FIG. 12 shows waveforms of another exemplary embodiment of the present invention. FIG. In this embodiment, the heating current waveform becomes 2205 so controlled or synchronized that the pulses 2206 by a constant phase angle Θ in phase with the pulses 2202 are. In such an embodiment, the phase angle is chosen to ensure stable operation of the process and to ensure that the arc is maintained in a stable state. In exemplary embodiments of the present invention, the phase angle θ is in the range of 30 to 90 degrees. In other exemplary embodiments, the phase angle is 0 degrees. Of course, other phase angles may also be used to achieve stable operation, and may range from 0 to 360 degrees, while in other exemplary embodiments the phase angle may be in the range of 0 and 160 degrees.

22C shows another exemplary embodiment of the present invention, wherein the hot wire current 2207 with the welding waveform 2201 is synchronized so that the hot-wire pulses 2208 phase in phase are the phase angle Θ about 180 degrees to the welding pulses 2202 is and only during the background section 2210 the waveform 2201 occurs. In this embodiment, the respective currents do not have their peaks at the same time. That is, the impulses 2208 the waveform 2207 begin and end during the respective background sections 2210 the waveform 2201 ,

In some example embodiments of the present invention, the pulse width of the hot and hot wire pulses is the same. However, the respective pulse widths may be different in other embodiments. For example, when a GMAW pulse waveform having a hot-wire pulse waveform is used, the GMAW pulse width is in the range of 1.5 to 2.5 milliseconds, and the hot-wire pulse width is in the range of 1.8 to 3 milliseconds, and the hot-wire pulse width is larger than the GMAW pulse width.

It should be noted that although the heating current is shown as a pulsed current, for some example embodiments the heating current may be a constant power as previously described. The hot wire current may also be a pulsed heating power, a constant voltage, a rising edge output, and / or a joules / time based output.

As explained herein, inasmuch as both streams are pulsed currents, they must be synchronized to ensure stable operation. There are many methods that can be used to accomplish this, including the use of synchronization signals. For example, the control unit 195 (which in one or both power supplies 170 / 2130 can be integrated) set a synchronization signal for starting the pulsed arc tip, and also can set the desired start time for the hot wire pulse peak. As discussed above, in some embodiments, the pulses for synchronous start-up are synchronized, while in other embodiments, the synchronization signal may set the start of the hot wire current pulse peak some time after the arc pulse peak; the time would be sufficient to obtain the desired phase angle for operation.

23 presents another exemplary embodiment of the present invention. In this embodiment, a GTAW welding or coating process is used, with a GTAW burner 2121 and an electrode 2122 create an arc into which a consumable material 2120 is introduced. Again, the arc and the hot wire 140 to the same puddle WP to form a bead WB as shown. The operation of a GTAW embodiment is similar to that described above in that the arc and the hot wire 140 interact with the same sweat puddle WP. Again, as with the GMAW operation described above, the current used to generate the arc in the GTAW operation is synchronized with the hot wire operation current. For example, the momentum relationship used in the 22A to 22C is shown. In addition, the control unit 195 control the synchronization between the power supplies using a dual state table or other similar control method. It should be noted that the consumables 2120 as a cold wire or as a hot wire consumable material can be fed to the weld. That is, both consumables 2110 and 140 can be heated as described herein. Alternatively, only one of the consumables needs 2120 and 140 to be the hot wire as described herein.

In any of the GTAW or GMAW embodiments discussed above (including the use of other arc techniques), the arc is located in the advancing position relative to the advancing direction. This is in each of the 21 and 23 shown. This is because the arc is used to achieve the desired penetration in the workpiece (s). That is, the arc is used to form the molten puddle and achieve the desired penetration in the workpiece (s). Subsequently, the hot-wire process follows on the arc process, which is described in detail in the present text. The addition of the hot wire process results in more consumables 140 to the puddle, but without the additional heat input through another welding arc, such as in a conventional tandem MIG process, where at least two arcs are used. That is, embodiments of the present invention can achieve significant deposition rates with significantly less heat input than known tandem welding processes.

As in 21 shown is the hot wire 140 led into the same puddle WP as the arc, but he trails the arc by a distance D after. In some exemplary embodiments, this distance is in the range of 5 to 20 mm, and in other embodiments, this distance is in the range of 5 to 10 mm. Of course, other distances can be used as long as the wire 140 supplied to the same molten puddle as that produced by the anticipatory arc. However, the wires are 2110 and 140 in the same molten puddle, and the distance D should be chosen so that there is minimal magnetic interference with the arc by the heating current used to heat the wire 140 is used. In general, the size of the puddle into which the arc and wire are collated depends on the welding speed, the arc parameters, the total power in the wire 140 , the type of material, etc., as well as factors in determining a desired distance between the wires 2110 and 140 are.

It should be noted that the operation of the hot wire current (for example 2203 . 2203 or 2207 ) is similar to that described in detail herein when an arcing event occurs either through the control unit 195 or the power supply 170 detected or predicted. That is, even when the current is pulsed, the current may be turned off or minimized as described herein when an arc is generated or detected. Furthermore, in some example embodiments, the background portions 2211 a current level below an arc generation level for the wire 140 (by the control unit 195 can be determined on the basis of user input information); and instead of shutting off the hot wire current when an arc is detected, the power supply can 170 put the power on the background for a while 2211 or until it is determined that the arc has died or does not enter (as previously described generally). For example, the power supply 170 a predetermined number of pulses 2203 / 2205 / 2207 skip or for a while, such as 10 to 100 ms, just do not pulse, causing the power supply 170 The pulses can start again to the wire 140 to heat to the appropriate temperature.

As described above, because at least two consumables 140 / 2110 be used in the same puddle, a very high deposition rate can be achieved with a heat input similar to that of a single arc operation. This offers significant advantages over tandem MIQ welding systems, which have a very high heat input into the workpiece. For example, embodiments of the present invention can easily achieve at least a 23 lb / h deposition rate with the heat input of a single arc. Other exemplary embodiments have a deposition rate of at least 35 lb / hr.

In exemplary embodiments of the present invention, the wires are 140 and 2110 the same, inasmuch as they have the same composition, diameter, etc. However, in other exemplary embodiments, the wires may be different. For example, the wires may have different diameters, wire feed rates and compositions as needed for the particular operation. In an exemplary embodiment, the wire feed rate is for the leading wire 2110 higher than that for the hot wire 140 , For example, the leading wire 2110 have a wire feed speed of 450 ipm while the trailing wire 140 has a wire feed speed of 400 ipm. In addition, the wires may have different sizes and compositions. Because the hot wire 140 does not have to cross an arc to be deposited in the puddle, the hot-wire 140 even have materials or components that are not usually well transferred by an arc. For example, the wire 140 have tungsten carbide or other similar hardfacing materials that can not be added to a typical welding electrode due to the arc. Furthermore, the leading electrode 2110 have a composition that is rich in wetting agents that can assist in wetting the puddle to obtain a desired caterpillar shape. In addition, the hot wire can 140 also contain slag elements that help protect the puddle. Therefore, embodiments of the present invention allow more flexibility in the chemical composition of the weld. It should be noted that because of the wire 2110 the leading wire is the arc welding operation with the leading wire to initiate penetration for the weld joint, the hot wire providing further filler material for the joint.

In some exemplary embodiments of the present invention, the combination of the arc and the hot wire may be used to balance the heat input to the weld deposit in accordance with the requirements and limitations of the actual operation performed. For example, the heat from the leading arc may be increased for interconnect applications where the heat from the arc helps maintain the burn-in required to bond the workpieces, and the hot wire is primarily used to fill the joint. However, in plating or material building processes, the hot wire wire feed speed can be increased to minimize thinning and increase material buildup.

Moreover, because different chemical compositions of the wire can be used, a weld joint having different layers can be produced, conventionally achieved by two separate passes. The lead wire 2110 may have the required chemical composition, which is required for a conventional first pass, while the trailing wire 140 may have the chemical composition required for a conventional second pass. In addition, in some embodiments, at least one of the wires may 140 / 2110 to be a filled wire. For example, the hot wire 140 a filled wire having a powder core depositing a desired material into the weld puddle.

24 FIG. 12 shows another exemplary embodiment of current waveforms of the present invention. FIG. In this embodiment, the hot wire current is 2403 an alternating current with the welding current 2401 (whether GMAW or GTAW) is synchronized. In this embodiment, the positive pulses 2404 the heating current with the pulses 2402 of the electricity 2401 synchronized while the negative impulses 2405 the heating current 2403 with the background sections 2406 of the welding current are synchronized. Of course, in other embodiments, the synchronization may be opposite by the positive pulses 2404 with the background 2406 be synchronized and the negative impulses 2405 with the pulses 2402 be synchronized. In another embodiment, there is a phase angle between the pulsed welding current and the hot wire current. When using an AC waveform 2403 For example, the alternating current (and hence the alternating magnetic field) can be used to help stabilize the arc. Of course, other embodiments may be used without departing from the spirit or scope of the present invention. For example, in a system operating with a submerged arc welding (SAW) operation, the SAW current waveform may be an AC waveform and the hot wire current waveform is an AC or a pulsed DC waveform, with all waveforms being synchronized with each other.

It should also be noted that embodiments of the present invention may be used when the welding current is a constant or nearly constant current waveform. In such embodiments, a heating alternating current 2403 used to maintain the stability of the arc. The stability is due to the constantly changing magnetic field of the heating current 2403 reached.

25 shows another exemplary embodiment of the present invention, wherein the hot wire 140 positioned between two tandem arc welding operations. In 25 Arc welding operations are shown as GMAW welding, but they can also be GTAW, FCAW, MCAW or SAW systems. In the figures, the anticipatory burner 2120 with a first power supply 2130 coupled and leads a first electrode 2110 via an arc welding operation to the puddle. The hot wire rushes ahead of the anticipatory arc 140 after (which is separated as discussed above). The hot wire 140 follows the trailing arc welding operation, which is a second power supply 2130 ' , a second burner 2120 ' and a second arc welding wire 2110 ' used. That is, the configuration is similar to that of a tandem GMAW welding system, but has a hot wire 140 in the common puddle between the burners 2120 and 2120 ' is deposited. Such an embodiment further increases the rate of deposition of materials into the puddle. It should be noted that embodiments of the present invention may utilize additional welding torches and / or hot wire consumables in a single operation and are not limited to the embodiments shown in the figures. For example, multiple hot wires may be used to deposit additional materials into the puddle during a single pass. As mentioned above, SAW processes may be used in place of the GMAW processes generally discussed herein. For example, the in 25 The embodiment shown using leading and trailing SAW processes having a similar configuration to that shown in this figure. Of course, instead of a shielding gas, a granular flux would be used to shield the arcs. The method or mode of operation and control as a whole are equally applicable to other welding methodologies, such as SAW, as discussed above. For example, shows 26A exemplary waveforms that may be used in a SAW system with a hot wire as described herein. As shown, the leading SAW current waveform is 2501 an alternating current waveform that has multiple positive pulses 2503 and several negative impulses 2505 during the lagging SAW current 2521 Also, an AC waveform is having several positive pulses 2523 and several negative impulses 2525 having the lagging waveform 2521 to the leading waveform 2501 is a phase angle α out of phase. In exemplary embodiments of the present invention, the phase angle α is in the range of 90 to 270 degrees. It should also be noted that in the illustrated embodiment, the ± offset between the waveforms 2501 and 2521 is different than the lagging waveform 2521 has a larger negative offset than the leading waveform 2501 , In other exemplary embodiments, the offset may be the same or may be reversed. The shown hot wire current 2510 is a pulse stream that has several positive pulses 2511 that has a background level 2513 are separated, with the waveform 2510 has a staggered phase angle θ different from the phase angle α. In an exemplary embodiment, the hot wire phase angle θ is in the range of 45 to 315 degrees, but differs from the phase angle α.

It should be noted that while the above discussion referred to a SAW OPeration, other example embodiments that operate with a similar synchronization methodology may be a GMAW, FCAW, MCAW, or GTAW operation, or combinations thereof.

As mentioned above, embodiments of the present invention can significantly increase the deposition of materials into the puddle while keeping the total heat input lower than with conventional tandem systems. However, some example embodiments may produce a shape of the weld bead WB that is higher than conventional tandem methods. That is, the weld bead WB projects generally higher beyond the surface of the workpiece and does not continue so far outward to the sides of the weld bead WB as in the case of tandem systems. This is generally because of the hot wire 140 helps quench the puddle behind the anticipatory arc welding operation. Therefore, some exemplary embodiments of the present invention utilize systems and components that assist in widening or widening the puddle during a welding or coating operation.

26 shows an exemplary embodiment where two GMAW burners 2120 and 2120 ' are not positioned in a line but are positioned next to each other as shown, with the hot wire 140 the two burners 2120 / 2120 ' lags. In this embodiment, the juxtaposition of the two GMAW arcs causes the puddle WP to broaden and aid in the puddle wiping to flatten the weld bead WB. As with the other embodiments, the hot wire rushes 140 the arc welding operation and may be positioned on the center axis of the weld bead WB after the arc welding operations. However, it is not necessary for the hot wire 140 remains on the central axis, since the hot wire during the Welding operation can also be oscillated or moved relative to the puddle.

27 shows another exemplary embodiment where lasers 2720 and 2720 ' may be used on either side of the weld puddle WP to aid in puddle flattening or to assist in wetting the puddle. The lasers 2720 / 2720 ' send each rays 2710 / 2710 ' on the sides of the puddle to add heat to the puddle and assist in wetting the puddle so that the puddle has a desirable shape. The lasers 2720 / 2720 ' may be of the type described herein and may be controlled in the manner described above. That means the lasers can be controlled by the control unit 195 or a similar device to produce the desired weld bead shape. Furthermore, instead of using two lasers to achieve the desired weld bead shape, a single laser with a beam splitter can also be used to scan the beam 2710 and directs the split jets to the appropriate position on the weld puddle to achieve the desired bead shape. It should be noted that for the sake of clarity, the anticipatory arc welding process 27 not shown.

In another exemplary embodiment, a single laser beam 2710 used to the puddle immediately downstream of the arc process or downstream of the hot wire 140 (in the feed direction), wherein the beam 2710 is oscillated from side to side to help flatten the puddle. In such embodiments, a single laser 2720 used and directed to areas of the puddle where it is desired to assist in puddling out during welding. The control and operation of the laser 2720 are similar to the control and operation of the laser 120 in relation to the above 1 etc. are described.

28 shows another exemplary embodiment of the present invention. In this exemplary embodiment, a GTAW (or GMAW, FCAW, MCAW) electrode is used 2801 used for the arc welding process, and a magnetic probe 2803 is next to the electrode 2801 positioned to control the movement of the arc during welding. The probe 2803 receives a current from the magnetic control and power supply 2805 if necessary with the control unit 195 can be coupled; and the current causes the generation of a magnetic field MF by the probe 2803 , The magnetic field interacts with the magnetic field generated by the arc and thus can be used to move the arc during welding. That is, the arc can be moved from side to side during welding. This side-to-side motion is used to widen the puddle and liberate the puddle to achieve the desired bead shape. Although not shown for clarity, the arc follows a hot wire consumable, as discussed herein, to provide additional filler for the weld bead. The use and implementation of a magnetic steering system is well known to those skilled in the art and need not be described in detail herein.

It goes without saying that the embodiments in each of the 26 and 28 (as well as the other embodiments shown and described herein) the laser 2720 may be used to assist in the formation of the weld puddle, as described herein.

Although the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the specific embodiments disclosed, but that the invention include all embodiments falling within the scope of the appended claims.

LIST OF REFERENCE NUMBERS

100

system

110

laser beam

110A

laser beam

110 '

cross-section

115

workpiece

120

laser device

121

beamsplitter

125

direction

130

Laser power supply

140

cored wire

150

Fülldrahtzufuhrvorrichtung

160

contact tube

160 '

component

170

Hot wire power supply

180

Motion controller

190

robot

195

Current control subsystem

200

start process

210

step

220

step

230

step

240

step

250

step

260

step

300

start process

310

step

320

step

330

step

340

step

350

step

410

Voltage waveform

411

Point

412

Point

420

Current waveform

425

rise

430

time interval

440

Set point value

450

current level

510

Voltage waveform

511

Point

512

Point

520

Current waveform

525

current level

530

time interval

601

joint surface

601A

melting puddle

603

joint surface

603A

melting puddle

605

surface

701

angled surface

703

angled surface

705

gap

707

bead

801

weld puddle

803

weld puddle

901

weld puddle

903

weld puddle

1000

weld

1010

laser source

1011

beam

1012

weld puddle

1020

laser source

1021

beam

1022

weld puddle

1030

cored wire

1030A

cored wire

1110

induction coil

1200

system

1210

Hot wire power supply

1220

user input

1221

positive connection

1222

negative connection

1223

Decision feedback sensing wire connection

1230

CPU or control unit

1240

Voltage detection circuit

1250

power module

1400

system

1410

heat sensor

1420

temperature sensor

1700

system

1710

engine

1720

Optical drive unit

1800

circuit

1801

resistance

1803

switch

1901

Laser screen assembly

1903

Vapor extraction system

2000

system

2110

welding electrode

2110 '

welding wire

2120

burner

2120 '

second burner

2121

burner

2122

electrode

2130

power supply

2130 '

second power supply

2150

Wire feeder

2201

Welding waveform

2202

current pulses

2203

Current waveform

2204

pulses

2205

Current waveform

2206

pulses

2207

Hot Wire Power

2208

Hot wire impulses

2210

Background section

2211

Background portions

2401

welding current

2402

Impulse

2403

Hot Wire Power

2404

positive impulses

2405

negative impulses

2406

Background portions

2501

Current waveform

2503

positive effects

2505

negative impulses

2510

Hot Wire Power

2511

positive impulses

2513

Background level

2521

SAW power

2523

positive impulses

2525

negative impulses

2710

beam

2710 '

beam

2720

laser

2720 '

laser

2801

electrode

2803

magnetic probe

2805

power supply

A

Point

B

Point

C

Point / center

D

Point / distance

e

Point

G

gap width

I

electricity

L

length

MF

magnetic field

P

weld puddle

V

tension

W

workpiece

W1

workpiece

W2

workpiece

WB

bead

WP

weld puddle

X

feed distance

Z

distance

α

angle

Θ

angle

θ

angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 4866247 [0125]
• US 5148001 [0125]
• US 6051810 [0125]
• US 7109439 [0125]
• US 2010/0096373 [0155, 0155]

Claims (15)

A welding system comprising: an arc generating power supply that provides an arc generation signal to an electrode to cause an arc between the electrode and at least one workpiece ( 115 ), so that a melt puddle on the at least one workpiece ( 115 ), wherein the arc generation signal comprises a plurality of current pulses; a hot wire power supply ( 170 ) generating a heating signal for heating at least one consumable such that the consumable in the molten puddle melts when the consumable is in contact with the molten puddle, the heating signal comprising a plurality of heating current pulses; and a control unit ( 195 ) which synchronizes the arc generation signal and the heating signal so as to maintain a constant phase angle between the current pulses of the arc generation signal and the heating current pulses, the hot wire power supply (FIG. 170 ) and / or the control unit ( 195 ) monitors a feedback related to the warming signal and compares the feedback to an arc generation threshold, and the hot wire power supply (FIG. 170 ) turns off the heating signal when the feedback reaches the arc generation threshold level. The system of claim 1, wherein the phase angle is in the range of 0 to 150 degrees, and wherein the phase angle is in particular 0 degrees. The system of claim 1, wherein the phase angle is in the range of 30 to 90 degrees. A system according to any one of claims 1 to 3, wherein the heating signal is an AC signal. A system according to any one of claims 1 to 4, wherein the electrode is a consumable material which is brought into a molten state by the arc generation signal and deposited in the molten puddle. System according to one of claims 1 to 5, further comprising at least one laser ( 120 ) whose laser beam ( 110 ) is directed to the molten puddle to add heat to the molten puddle, and / or further comprises at least one magnetic field generating device that generates a magnetic field to interact with the arc. A system according to any one of claims 1 to 6, comprising: a second arc generating power supply ( 2130 ) which outputs a second arc generation signal to a second electrode to generate a second arc between the first electrode and at least one workpiece so that the second arc is in contact with the molten puddle, the second arc generation signal having a plurality of second current pulses ( 2202 ); wherein the control unit synchronizes the arc generation signals and the heating signals so as to maintain a constant phase angle between the current pulses of the arc generation signals and the heating current pulses. The system of claim 7, wherein the first and second arc generation signals are sub-arc arc welding signals. The system of claim 7 or 8, wherein each of the first and second arc generation signals and the heating signal are synchronized to be out of phase with each other. The system of any one of claims 7 to 9, wherein at least one of the first and second arc generation signals is an AC signal. A system configured to: generate an arc generation signal and output the arc generation signal to an electrode for generating an arc between the electrode and at least one workpiece ( 115 ) to a melt puddle on the at least one workpiece ( 115 ), wherein the arc generation signal comprises a plurality of current pulses; Generating a heating signal to heat at least one consumable such that the consumable in the molten puddle melts when the consumable is in contact with the molten puddle, the heating signal comprising a plurality of heating current pulses; Synchronizing the arc generation signal and the heating signal so as to maintain a constant phase angle between the current pulses of the arc generation signal and the heating current pulses; and monitoring a feedback signal related to the heating signal and comparing the feedback to an arc generation threshold, and turning off the heating signal when the feedback reaches the arc generation threshold level. The system of claim 11, wherein the phase angle is in the range of 0 to 180 degrees, or wherein the phase angle is 0 degrees. The system of claim 11, wherein the phase angle is in the range of 30 to 90 degrees. The system of any one of claims 11 to 13, wherein the heating signal is an AC signal. The system of claim 13, wherein the electrode is a consumable material that is brought to a molten state by the arc generation signal and deposited in the molten puddle; and / or that furthermore comprises at least one laser beam ( 110 ) on the molten puddle to add heat to the molten puddle; and / or further comprising generating a magnetic field to interact with the arc.

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