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EP4652008A1 - Commande de processus d'assemblage par intervalle - Google Patents

Commande de processus d'assemblage par intervalle

Info

Publication number
EP4652008A1
EP4652008A1 EP24710415.1A EP24710415A EP4652008A1 EP 4652008 A1 EP4652008 A1 EP 4652008A1 EP 24710415 A EP24710415 A EP 24710415A EP 4652008 A1 EP4652008 A1 EP 4652008A1
Authority
EP
European Patent Office
Prior art keywords
pause
joining
arc
phases
time
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24710415.1A
Other languages
German (de)
English (en)
Inventor
Dominik SÖLLINGER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fronius International GmbH
Original Assignee
Fronius International GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fronius International GmbH filed Critical Fronius International GmbH
Publication of EP4652008A1 publication Critical patent/EP4652008A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/09—Arrangements or circuits for arc welding with pulsed current or voltage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K1/00—Soldering, e.g. brazing, or unsoldering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/09—Arrangements or circuits for arc welding with pulsed current or voltage
    • B23K9/091—Arrangements or circuits for arc welding with pulsed current or voltage characterised by the circuits
    • B23K9/092—Arrangements or circuits for arc welding with pulsed current or voltage characterised by the circuits characterised by the shape of the pulses produced
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/09—Arrangements or circuits for arc welding with pulsed current or voltage
    • B23K9/091—Arrangements or circuits for arc welding with pulsed current or voltage characterised by the circuits
    • B23K9/093—Arrangements or circuits for arc welding with pulsed current or voltage characterised by the circuits the frequency of the pulses produced being modulatable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/095—Monitoring or automatic control of welding parameters
    • B23K9/0953—Monitoring or automatic control of welding parameters using computing means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00—Arc welding or cutting
    • B23K9/10—Other electric circuits therefor; Protective circuits; Remote controls
    • B23K9/1006—Power supply
    • B23K9/1012—Power supply characterised by parts of the process
    • B23K9/1031—Reduction of the arc voltage beneath the arc striking value, e.g. to zero voltage, during non-welding periods

Definitions

  • the present invention relates to an arc interval joining method which comprises a sequence of arc phases and pause phases, wherein the arc phases have a predetermined arc duration and alternate in time with the pause phases, and wherein in the arc phases a joining current flows between a joining electrode and a workpiece to join the workpiece and in the pause phases no joining current flows.
  • the invention relates to a welding device for carrying out an arc interval joining method, comprising a welding torch for introducing energy at a welding or soldering point on a workpiece to produce a molten pool, comprising a feed unit for feeding a welding wire to the molten pool, wherein the welding wire can be melted in the region of the molten pool by the energy introduced by the welding torch in order to produce a weld seam on the workpiece and comprising a control unit for controlling the welding device.
  • Arc interval welding and arc interval brazing are two widely used joining processes that are particularly suitable for regulating temperature distributions in joined workpieces or for controlling the heat input that is introduced into a workpiece during arc welding or arc brazing.
  • the following explanations deal with arc interval welding and arc interval brazing, whereby the generic term "arc interval joining" is used to describe both of these joining processes.
  • Arc interval joining processes have arc phases and pause phases, whereby in arc phases an arc burns between a joining electrode and a workpiece (at least temporarily), and in pause phases, in contrast, no arc burns in order to reduce the heat input.
  • a joining current flows, which introduces heat into a workpiece to be joined, while in a pause phase the workpiece does not experience any heat input due to the lack of a burning arc and consequently the lack of flowing joining current and can therefore cool down and give off heat.
  • the regulation of the heat input into a workpiece to be joined is of great importance, especially when welding or soldering thin sheets.
  • the amount of heat introduced into a workpiece during arc interval joining can be influenced by adjusting the duration of arc and pause phases, which in turn can affect the heat input in a temperature distributions occurring in the joined workpiece can be regulated. Because of its direct impact on the quality factors mentioned, the possibility of regulating temperature fields is an important reason for using an arc interval joining process instead of an alternative joining process.
  • arc duration the duration of both arc phases
  • pause duration pause phases
  • the points in time at which an arc is extinguished are decisive
  • ignition points the points in time at which the arc is reignited
  • an arc is extinguished at an extinguishing point in time at the beginning of a pause phase and is reignited at an ignition point in time at the end of a pause phase.
  • the pause duration of the corresponding pause phase is therefore determined from the time between an extinguishing point in time and an ignition point in time immediately following this extinguishing point in time.
  • the time period between an ignition point and an extinguishing point immediately following this ignition point defines the arc duration of a corresponding arc phase.
  • the duration of arc and pause phases is typically in the range of 300 milliseconds to 500 milliseconds.
  • Arc durations and pause durations can therefore have values of 250 milliseconds or 300 milliseconds or 350 milliseconds or 400 milliseconds or 450 milliseconds or 500 milliseconds. Depending on the application, however, longer or shorter arc phases and/or pause phases can also occur (e.g. even shorter than 100 milliseconds).
  • determining ignition times is often complex and, depending on the situation, associated with various difficulties.
  • gas metal arc welding such as MIG welding or MAG welding, but also in MIG soldering or MAG soldering, the arc can be reignited by means of an electrical contact between a joining electrode that melts during welding, such as a melting welding wire electrode, and a workpiece (short-circuit ignition). If the joining electrode touches the workpiece for reignition, reignition can be brought about either by means of a high ignition current, or the welding or joining electrode can be lifted off the workpiece during ignition of the arc (“drawn ignition”) and the arc can be “drawn up”.
  • the question of when an arc will actually be reignited in such a situation is influenced by a number of factors, such as the distance that the welding electrode has to cover in a pause phase before it comes into contact with the workpiece again (hereinafter referred to as the "creep path"), or the so-called creep speed with which the welding electrode is moved towards the workpiece in the pause phase, or the surface quality of a workpiece to be welded, or the level of the welding voltage applied for reignition. If these factors fluctuate, the resulting ignition times also fluctuate as a direct consequence. An actual ignition time can therefore deviate from a specified target ignition time.
  • the independent claims for an arc interval joining method mentioned at the beginning and for a welding device mentioned at the beginning provide for determining a first pause duration of a first pause phase during the arc interval joining method and, in the event that the determined first pause duration deviates from a predetermined target pause duration, changing at least one joining parameter of the arc interval joining method that influences the pause durations of the pause phases in order to reduce a deviation between a second pause duration of a second pause phase, which follows the first pause phase in time, and the predetermined target pause duration in comparison to the deviation of the first pause duration from the target pause duration.
  • the procedure according to the invention makes it possible to specifically match arc durations and pause durations to a predetermined, desired or required heat input that is to be introduced into a workpiece to be joined during the arc interval joining process.
  • the predetermined target pause duration is advantageously matched to the heat input to be introduced and can be determined, for example, from the heat input to be introduced using a predetermined mathematical relationship. In this way, the joining quality that can be achieved with an arc interval joining process can be noticeably improved.
  • first pause phase and the second pause phase can in principle be any pause phases selected during the arc interval joining process, with the proviso that the second pause phase is timed after the first pause phase.
  • the first pause phase and the second pause phase are therefore by no means necessarily the absolute first and the absolute second pause phase of the arc interval joining process, but can just as well be pause phases that occur later in the course of an arc interval joining process.
  • the second pause phase does not necessarily have to be the pause phase that immediately follows the first pause phase. There can also be one or more further pause phases between the first and second pause phases.
  • the joining current occurring in the arc interval joining process is particularly suitable for identifying arc phases and pause phases, since a joining current typically flows continuously during the arc phases, even if, for example, a pulsed arc is used (for example, a joining current also flows in an arc phase, even if an arc is interrupted by a short circuit between the welding wire and the workpiece, especially since in arc phases a joining voltage is typically still present even in the event of a short circuit).
  • an arc can also burn continuously during the arc phases.
  • no joining current flows during the pause phases, and no arc burns either.
  • An arc phase can therefore be understood as a phase in which a joining current flows.
  • the joining current can be interrupted for particularly short periods of time during the arc phases. These particularly short periods of time are usually shorter than 10 milliseconds, or shorter than 5 milliseconds, or shorter than 0.5 milliseconds. Phases in which a joining current always flows and which is therefore only interrupted for a very short time, i.e. shorter than 10 milliseconds, preferably shorter than 5 milliseconds or shorter than 0.5 milliseconds, are also considered arc phases in the context of these explanations.
  • a pause phase can therefore be interpreted as a phase in which no joining current flows and which is preferably longer than 10 milliseconds or longer than 20 milliseconds or longer than 50 milliseconds.
  • the arc interval joining method can be an arc interval welding method or an arc interval soldering method, wherein in the arc phases an arc burns at least temporarily, preferably continuously, between the joining electrode and the workpiece, wherein the joining current for joining flows from the joining electrode through the arc between the joining electrode and the workpiece.
  • the determination of a first pause duration can be carried out continuously, which means that a first pause duration is not only determined at one point in time during the arc interval joining process, but that this happens multiple times, preferably at points in time that are spaced apart from one another by a predetermined time interval.
  • Each pause duration determined in this way can be a starting point for changing a joining parameter in order to bring a later pause duration closer to the predetermined target pause duration.
  • the invention can also be used in scenarios in which direct measurement of pause durations is not possible, for example because only limited sensors are available.
  • a description parameter for an indirect determination in particular a time period between an activation time, at which during a pause phase in particular a wire feed is reactivated and/or a voltage for supplying a joining electrode is increased again, and an ignition time immediately following the activation time can be determined as a parameter value of the description parameter, or a creeping path that a welding wire travels between such an activation time and an ignition time immediately following the activation time.
  • the arc interval joining process according to the invention can advantageously be a MIG welding process or a MAG welding process in which a consumable welding wire is provided as a joining electrode in the arc phases, or it can be a MIG soldering process or a MAG soldering process in which a consumable solder is provided as a joining electrode is provided. If a consumable solder is provided as part of a MIG or MAG soldering process, this is referred to as “melt soldering with temporarily liquid solders", whereby molten solder forms a liquid phase and thus a molten pool.
  • a molten pool is created on the workpiece in the area of a joint by the arc that burns at least temporarily between the joining electrode and the workpiece, both during welding and during soldering.
  • the respective molten pool is created - during welding the base material and the filler material are melted, i.e. the workpiece and the welding electrode, and during soldering only the filler material and not the workpiece - both during welding and soldering a joining electrode is supplied and the joining electrode is melted by the energy introduced in order to create a weld seam or solder seam and thus a molten pool.
  • a molten pool therefore corresponds to a liquid phase of filler material and/or material in the area of the joint.
  • the arc is extinguished and the wire feed is stopped at the beginning of the pause phases during both welding and soldering, the wire feed is reactivated at an activation time after a rest interval in the pause phases and a time period between the activation time and an ignition time immediately following the activation time is determined as a parameter value of the description parameter and/or a creeping path that the welding wire travels between the activation time and an ignition time immediately following the activation time is determined as a parameter value of the description parameter.
  • a wire feed speed can be used and thus changed in an advantageous manner, and/or a joining current in an arc phase, and/or an activation time, and/or a distance between the welding wire and the workpiece at an activation time, and/or a time period between an extinguishing time and an activation time, and/or a current-time area in an arc phase.
  • Fig.1 a standardized structure of a welding device
  • Fig.2 shows a schematic sequence of an arc interval joining process according to the state of the art
  • Fig.3a shows a schematic sequence of an arc interval joining process according to the invention
  • Fig.3b shows an arc interval joining method according to the invention comprising a change in the joining current and the wire feed speed
  • Fig.4a, Fig.4b each show a coupling plan for implementing the joining method according to the invention.
  • MSG welding device 1 for metal inert gas welding (MSG welding), which includes in particular the known methods of metal inert gas welding (MIG welding) and metal active gas welding (MAG welding).
  • MIG welding metal inert gas welding
  • MAG welding metal active gas welding
  • the invention is in no way restricted to the field of metal inert gas welding and can also be used in the field of tungsten inert gas welding (TIG welding) or another welding technique.
  • the MSG welding device 1 under consideration can, as is known, also be used for arc soldering.
  • a shielding gas SG suitable for soldering and a solder suitable for soldering as an additional material, i.e. as a consumable joining electrode 7. Otherwise, no changes, e.g. changes to the welding torch 4, etc., are required, so that in particular the control of a MSG welding device 1 as shown in Fig.1 does not differ during soldering and welding.
  • the present invention can accordingly also be used in the context of interval soldering, which is carried out on the MSG welding device 1 according to Fig.1, so that the following statements, mutatis mutandis, also apply to both welding and soldering.
  • the general terms joining current I, joining voltage U, joining electrode 7, etc. are used below, instead of the terms otherwise commonly used in welding, welding current I, welding voltage U, welding electrode 7, welding wire 7a, etc., and instead of the terms otherwise commonly used in soldering, soldering current I, soldering voltage U, soldering electrode 7, etc.
  • the MSG welding device 1 has a power source 2, a hose package 3, a welding torch 4 and a protective gas container 5 with a protective gas SG.
  • the protective gas container 5 is connected to the welding torch 4 by means of a protective gas line 8.
  • a pressure regulator (not shown), for example in the form of a known bottle fitting, can be provided on the protective gas container 5 or in the protective gas line 8, which is generally used to regulate the flow of the protective gas SG.
  • low-reactivity inert protective gases SGi such as argon (Ar) or helium (He)
  • active protective gases SGa such as oxygen (O) or carbon dioxide (CO2)
  • the protective gas container 5 and the protective gas line 8 can of course also be omitted. Mixtures of argon, carbon dioxide and hydrogen are usually used as the protective gas SG for MSG soldering.
  • a joining electrode 7 in the form of a welding wire 7a can be arranged in the power source 2, which is usually wound on a welding wire roll 13.
  • a feed unit 12 is arranged, which is driven by a feed drive unit 12a.
  • a hard solder such as a silver solder or a brass solder or a copper-based solder
  • a soft solder such as a tin solder, which can also be unrolled from a welding wire roll 13.
  • the welding wire 7a on the welding wire roll 13, and also the feed unit 12, can also be arranged outside the power source 2 in a separate unit.
  • welding devices 1 with several feed units 12, which bring about the required wire feed in an advantageously coordinated manner.
  • a feed unit 12 can also be arranged in the area of the joining electrode 7. This does not result in any restrictions for the applicability of the present invention.
  • the feed drive unit 12a is controlled by a control unit 14, which in turn usually communicates with a user interface 17.
  • a user Via a user interface 17, a user can specify certain joining parameters as required, such as a joining voltage U, a joining current I, a wire feed speed vd with which the welding wire 7a is fed to the joining point, etc.
  • predefined welding programs with certain preset joining parameters can be stored in the control unit 14, which can be selected by the user via the user interface 17, or by a higher-level control, such as a control of a welding robot.
  • a power unit 15 is also arranged in the power source 2, which is controlled (or regulated) by the control unit 14 and which is connected to an external voltage supply 16.
  • the control unit 14 can therefore be equipped to control and/or regulate the entire MSG welding device 1 or certain components of the MSG welding device 1, such as the feed unit 12, the control of the shielding gas feed and/or the power unit 15 and/or the movement of the welding torch 4.
  • a control unit 14 can be implemented in the form of microprocessor-based hardware, a microcontroller, or an integrated circuit (ASIC, FPGA), and can of course also be arranged outside the power source 2.
  • the power unit 15 of the power source 2 supplies the welding torch 4 with the required joining current I and a joining voltage U via a power line 19 arranged in the hose package 3.
  • the joining voltage U is applied to the joining electrode 7 for welding, so that the joining current I flows when an arc is burned.
  • the welding wire 7a (by means of the feed unit 12) and the shielding gas SG, and possibly also a cooling medium for cooling the welding torch 4, are usually also fed to the welding torch 4 via the hose package 3.
  • Control lines can also be provided in the hose package. However, several individual lines for the respective media, controls and energies can be provided as the hose package 3.
  • a first electrical potential is applied to a workpiece 6 made of a base material e by means of an electrical connection 18, and a second electrical potential is applied to the welding wire 7a as the joining electrode 7, as a result of which a joining current I flows between the welding wire 7a and the workpiece 6 after an arc 11 is ignited.
  • Various types of arc can be used here, such as short arcs or transition arcs or spray arcs or pulsed arcs or cold metal transfer (“CMT”) arcs, which are well known to those skilled in the field of joining technology.
  • a weld seam 10 is welded onto the workpiece 6; this is referred to as build-up welding.
  • two workpieces 6, 6a could also be joined, as symbolized by the dashed line, in what is then known as joint welding.
  • the arc 11 is surrounded by the shielding gas SG flowing out of the welding torch 4 in the form of a shielding gas bell 9 in order to protect the molten material in the area of the Weld seam 10 is shielded from the environment.
  • welding or soldering could in principle also be carried out without shielding gas SG.
  • a shielding gas container 5 and a shielding gas line 8 could be dispensed with.
  • the welding wire 7a is fed to the arc and melted in the arc, with the arc burning between the joining electrode and the workpiece.
  • the welding wire 7a i.e. a melting joining electrode 7 is fed to the joining point at a specific wire feed speed Vd, which can depend on several influencing factors.
  • a constant wire feed speed Vd is generally selected, for example as a function of the set joining current I.
  • the wire feed speed Vd can also be selected, for example, as a function of a welding speed v s with which the welding torch 4 is moved relative to the workpiece 6.
  • the interval joining method according to the invention can be used in an advantageous manner for welding or soldering on a MSG welding device 1 as shown in Fig.1, wherein welding can be carried out automatically or by hand.
  • extinguishing an arc 11 is possible in a convenient and precise manner, particularly by interrupting the joining voltage U. Stopping or reducing the speed of the wire feed is also generally problem-free, although it should be noted that the reduction in the speed of the wire feed can be started exactly at the beginning of the pause phases PP, or slightly before the beginning of a pause phase PP, or only slightly after the beginning of a pause phase PP. These relationships will be discussed in more detail later. Often, a welding wire 7a continues to burn for a short time even after the arc 11 has been extinguished during a so-called burn-off period, particularly since high heat is typically stored in the area of the end of the welding wire 7a facing the workpiece 6.
  • This burning in addition to any movement of the welding wire 7a by the feed unit 12, influences the remaining distance, the so-called creeping path Sd, between the axial end of the welding wire 7a and the workpiece 6 at the beginning of a pause phase PP, specifically the distance between the end of the welding wire 7a facing the workpiece 6 and the workpiece 6.
  • reigniting an arc 11 in contrast to extinguishing it, proves to be difficult in many cases. Specifically, reigniting an arc in the case of a short-circuit ignition requires electrical contact between the welding wire 7a and the workpiece 6. However, since the wire feed is initially reduced to zero in the pause phases PP and the welding wire 7a is away from the workpiece 6 by the creeping distance Sd, it is necessary to initially reactivate the wire feed in the pause phase PP in order to move the welding wire 7a back towards the workpiece 6. In order to enable stable reignition of the arc 11, a wire feed speed Vd is typically used that is lower than that in the arc phases LP and is referred to in welding technology as the creeping speed.
  • a point in time in a pause phase PP at which the wire feed is reactivated and typically the voltage U applied to the joining electrode 7 is increased again for reignition is referred to in this patent application as the activation point in time TA.
  • An activation point in time TA divides a pause phase PP into two intervals. The interval between an extinguishing point in time TL at the beginning of a pause phase PP and an activation point in time TA is referred to below as the rest interval AR, and the interval following the activation point in time TA until the arc 11 is reignited at an ignition point in time TZ is referred to as the activation interval AA.
  • activation points in time TA these points in time can be specified with a high degree of temporal precision (the activation of a power unit 15 or a feed drive unit 12a is usually only subject to negligible disturbances).
  • Target values can also be provided for the duration of rest intervals AR, which can be implemented in practice with less effort and high accuracy.
  • the creeping path Sd to be covered depends, among other things, on the aforementioned burn-off of the welding wire 7a after the end of an arc phase LP, i.e. on the length of the welding wire 7a that is still burned off due to the heat stored in the welding wire 7a.
  • the end of the welding wire 7a facing the workpiece e therefore moves further or closer away from the workpiece 6 depending on the burn-off, which increases or decreases the creeping path Sd to be covered subsequently.
  • the creeping path Sd is therefore the distance between the end of the welding wire 7a facing the workpiece 6 and the workpiece 6 at an activation time TA.
  • a changing surface profile of the workpiece 6, over which the welding torch 4 moves can also influence the creeping path Sd.
  • the movement of the welding wire 7a through the feed unit 12 can also influence the creeping path Sd.
  • Fig.2 shows schematic time profiles of the joining parameters joining current I, joining voltage U and wire feed speed Vd, which can occur in an interval joining process according to the state of the art, for example on a MSG welding device 1 according to Fig.1.
  • the wire feed speed Vd has a value VdL during the arc phases LPi, LP2, LP3 and, in this exemplary embodiment, is initially reduced to the value zero during the pause phases PP1, PP2.
  • the joining voltage U and, as a consequence, the joining current I are also initially reduced to the value zero at the beginning of the pause phases PP1, PP2.
  • the wire feed in the direction of the workpiece 6 is started again during the pause phases PP1, PP2 at an activation time TA1, TA2, with a lower wire feed speed Vdp initially being used as the creeping speed.
  • the voltage U is also increased again at the activation times TA1, TA2 in order to be able to immediately reignite the arc 11 upon renewed contact between the welding wire 7a and the workpiece 6.
  • the arc phases LP are each between an ignition time TZ, at which the arc 11 is ignited, and an extinguishing time TL, at which the arc 11 is extinguished, and that the pause phases PP are each between an extinguishing time TL and an ignition time TZ.
  • a target pause duration TP S0 H is specified, whereby it is desired that the actual durations of the pause phases PP1, PP2 correspond as precisely as possible to this target pause duration TP S0 H.
  • the fact that this requirement is not always met in practice can be deduced in particular from the second pause phase PP2 shown.
  • the duration of the second pause phase PP2 is noticeably longer than the duration of the first pause phase PP1 and deviates significantly from the specified target pause duration TP S0 H.
  • the reason is, for example, a changed (increased) burn-off of the welding wire 7a, so that a larger creeping path Sd must be covered. Due to the chain of effects explained at the beginning of pause durations - amount of heat introduced - weld seam defects, such deviations are highly undesirable.
  • the invention provides for determining a first pause duration TP1 of a first pause phase PP1 during the arc interval joining process and, in the event that the determined first pause duration TP1 deviates from a predetermined target pause duration TP S0 H, changing at least one joining parameter of the arc interval joining process, which influences the pause durations of the pause phases PP, in such a way that a deviation between a second pause duration TP2 of a second pause phase PP2, which follows the first pause phase PP1 in time, and a predetermined target pause duration TP S0 H is reduced in comparison to the deviation of the first pause duration TP1 from the target pause duration TP S0 H.
  • An efficient way of implementing the invention is to directly measure the pause durations TP of the pause phases PP.
  • the extinguishing times TL are usually known, and the ignition times TZ are also often automatically monitored in welding devices 1, such as the one shown in Fig.1, for example by monitoring the joining current I.
  • the pause duration TP of a pause phase can be deduced from the time difference between an ignition time TZ and the preceding extinguishing time TL.
  • the duration of an activation interval AA between an activation time TA and a subsequent ignition time TZ can also be measured in order to determine the pause duration of a pause phase PP.
  • activation times TA can be determined with high precision, so that the duration of a rest interval AR is usually known. If the durations of both the rest interval AR and the activation interval AA in a pause phase PP are known, the pause duration TP of the pause phase PP can be determined by simple summation.
  • the duration of an activation interval AA is measured directly.
  • the creeping path Sd that the welding wire 7a has covered in a previous activation interval AA can also be determined. In the cases relevant for practice, this information is immediately available in a control unit 14 for controlling a feed drive unit 12a. Since the wire feed speed Vdp used in the pause phases PP is of course known, the associated duration of an activation interval AA can easily be deduced from the path covered by the welding wire 7a after an activation time TA, in the simplest case by division. The total duration of a pause phase PP is also obtained in this case by summing the durations of the rest interval AR and the activation interval AA.
  • an activation time TA can be shifted in time, e.g. closer to the previous extinguishing time TL or further away from the previous extinguishing time TL, whereby the desired correction of the pause durations TP can be achieved.
  • the wire feed speed Vdp specified after an activation time TA can be increased or decreased in order to increase or decrease the duration of the activation interval AA and thus correct the pause durations TP.
  • the creeping path Sd which is decisive for the duration of an activation interval AA, is influenced by the level of the joining current I used in the previous arc phase LP.
  • the reason for this is that a higher joining current I leads to more heat stored in the welding wire 7a, which leads to greater burn-off and thus to a larger creeping path Sd. If the creeping speed Vd remains the same but the creeping path Sd changes, the duration of an activation interval AA and thus the resulting pause durations PP change immediately for obvious reasons.
  • the joining parameters mentioned above can also be changed in combination to influence an ignition point TZ.
  • Fig.3a How the procedure according to the invention can affect the time courses of joining current I, joining voltage U and wire feed speed Vd is shown in Fig.3a.
  • a pulsed joining voltage U which results in a pulsed joining current I, is used in the arc phases LPi, LP2, LP3.
  • the wire feed speed Vd in Fig.3a also has a value VdL during the arc phases LP1, LP2, LP3 and is initially reduced to the value zero during the pause phases PP1, PP2.
  • the joining voltage U and the joining current I are also initially reduced to zero at the beginning of the pause phases PP1, PP2, PP3.
  • the pause duration of the first pause phases PP1 deviates noticeably from the specified target pause duration TP S0 H.
  • the second activation time TA2 is moved forward, i.e. closer to the previous extinguishing time TL2. This results in a shorter rest interval AR2 compared to the first pause phase PP1 and thus a pause duration TP2 of the entire pause phase PP2 that already corresponds very precisely to the target pause duration.
  • the temporal position of the activation time TA3 is maintained compared to the second pause phase PP2, i.e. a rest interval AR3 of the same length is provided in the third pause phase PP3 as in the second pause phase PP2, so that a satisfactory agreement with the specified target pause duration TP S0 H is maintained.
  • the invention thus makes it possible to achieve a constant pause and arc duration after only a few interval cycles.
  • the determination of the pause durations TP can be implemented by determining a parameter value PW of a description parameter PT of the arc interval joining method, such as the duration of an activation interval AA or a creeping path Sd that describes the first pause duration TP1, in order to determine the first pause duration TP1, and from this parameter value PW the at least one pause duration TP1 required to implement the invention is determined.
  • a parameter value PW of a description parameter PT of the arc interval joining method such as the duration of an activation interval AA or a creeping path Sd that describes the first pause duration TP1
  • the parameter value PW of the description parameter PT various methods known in particular from control engineering or signal processing can be used, whereby the parameter value PW can be determined, among other things, by means of a filter, such as in particular a Kalman filter, or by means of an observer, such as in particular a Luenberger observer, or by means of an adaptive system or by means of a neural network from measured values of one or more joining parameters of the arc interval joining process.
  • a filter such as in particular a Kalman filter
  • an observer such as in particular a Luenberger observer
  • an adaptive system such as in particular a neural network from measured values of one or more joining parameters of the arc interval joining process.
  • the joining current I flowing in the arc phases LP influences the burn-off of a welding wire 7a or a solder, and thus has a direct effect on the creeping path Sd that occurs in the pause phases PP.
  • the energy transported by a time course of an electrical current results from the current-time area covered by this time course. If the current-time area is larger, more electrical energy and thus more heat is transferred, in this case into a welding wire 7a or into a solder, which leads to greater burn-off. If the current-time area is smaller, there is less heat input and therefore less burn-off. In a corresponding way, it is possible to control the heat remaining in a welding wire 7a at the end of an arc phase LP, and thus the burn-off and consequently the creeping path Sd to be covered, by appropriately changing the joining current I.
  • joining current I In addition to the joining current I, as mentioned, it is primarily the wire feed speed Vd that influences the creeping path Sd to be covered starting from an activation time TA, so that in a particularly advantageous embodiment the joining current I and the wire feed speed Vd can be changed in combination in order to regulate the creeping path Sd and thus ultimately the pause durations TP of the pause phases PP in question.
  • a change in the joining current I can have within the scope of this invention is shown in Fig.3b.
  • the amplitude of the last joining current pulse is reduced from the first arc phase LPi, which leads to a reduction in the heat transferred and thus to a reduction in the burn-off that occurs.
  • a so-called "run-on" of the wire feed speed Vd is provided in the situation shown in Fig.3b. This means that the reduction in the wire feed speed Vd does not begin immediately at the extinguishing time TL2, TL3, but only slightly after the start of the subsequent pause phases PP2, PP3.
  • a current-time area can be specified directly in an advantageous manner, for example a total current-time area swept in an arc phase LP, or a current-time area swept in the second half of an arc phase LP.
  • the joining current I described it is possible to implement a so-called "burn-off program" and thus to achieve a predetermined melting rate of a welding wire 7a or a solder.
  • various attributes of a joining current I can be changed to regulate the burn-off, such as a peak value of the joining current I or an effective value of the joining current I or the frequency of pulses of a joining current I, or other attributes of a joining current I.
  • the amplitude of the last joining current pulse I can also be increased in order to increase the remaining heat in the welding wire 7a and thus cause more burn-off.
  • the change in the height of joining current pulses is also by no means limited to the last joining current pulse, so that the amplitudes of several current pulses at the end of an arc phase LP can be increased or reduced in the same way, e.g. the amplitudes of the last two joining current pulses or the amplitudes of the last three joining current pulses.
  • the time at which the reduction in the wire feed speed Vd begins can not only be postponed to a subsequent pause phase, but can also be brought forward. Within the scope of the invention, a reduction in the wire feed speed Vd can therefore begin before an extinguishing time TL, within an arc phase LP, which ultimately contributes to an increase in the creeping path Sd.
  • the method steps according to the invention can of course be implemented in software, preferably in a control unit such as the control unit 14 shown in Fig.1.
  • the second pause phase PP2 can only begin after the control time TR, so that it is ensured that the adaptation of the joining parameter to be changed has already taken place before a new pause phase PP begins.
  • Figure 4a summarizes the basic idea of the present invention in the form of a standard control loop that is well known from control engineering.
  • the welding device 1 represents the section to be controlled, from which the occurring pause durations TP of the pause phases PP are determined.
  • a determined pause duration TP is compared with a predetermined target pause duration TP S0 H, resulting in a pause duration control error e T p.
  • the pause duration control error eyp is fed to a controller Ri as an input variable, which uses this to determine a changed activation time TA as a control variable.
  • the determined activation time TA is in turn used when operating the welding device 1, whereby the actually occurring pause durations TP adjust to the target pause duration TPsoii when using a suitably designed controller.
  • the controller R1 can be a PID controller or a model predictive controller or a flatness-based controller or a backstepping controller or a sliding-mode controller, which can of course be implemented in a discrete-time formulation in software according to the above explanations.
  • the variable k stands for a time-discrete index, so that TAk and TAk+i represent two consecutive activation times.
  • This simple control law which corresponds to an integrator with a gain factor of 1/Ts, always shifts a subsequent activation time TAk+i by exactly the difference between the pause duration and the target pause duration at the previous time.
  • joining current I and the wire feed speed Vd are also used in addition to the activation time TA to implement the invention, is shown in Fig. 4b.
  • a first control loop is provided, where, as in Fig.4a, a determined pause duration TP is compared with a specified target pause duration TP S0 H, from which a Pause duration control error e T p is determined and from this a changed activation time TA is determined as the first manipulated variable.
  • a special feature of the controller R2 shown in Fig.4b is that the controller R2 can influence two manipulated variables, on the one hand the activation time TA, and on the other hand the wire feed speed Vd used in the pause phases.
  • the wire feed speed Vd used in the pause phases PP can be used to influence the duration between activation time TA and the subsequent ignition time TZ, so that the wire feed speed Vd can of course also be used as a manipulated variable to change the duration of an activation interval AA.
  • the wire feed speed Vd at the end of an arc phase LP is also conceivable to use the wire feed speed Vd at the end of an arc phase LP as a manipulated variable to change pause durations TP.
  • pause durations TP which deviate from a predetermined target pause duration TP S0 H arise in particular from changing creeping paths Sd, so that in Fig.4b, by means of a further controller R3, it is provided not only to regulate the pause duration TP itself, but also to determine the creeping path Sd, to compare this with a predetermined target creeping path Sd,soii, to determine a creeping path control error e s from this and to feed this creeping path control error e s to the further controller R3 for control.
  • the options provided within the scope of the invention for influencing or controlling the creeping path Sd, for example by changing a joining current I or a wire feed speed Vd, were explained in detail earlier. It should be noted that the lower of the control circuits shown in Fig.4b can also be provided on its own.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Theoretical Computer Science (AREA)
  • Arc Welding Control (AREA)
  • Arc Welding In General (AREA)

Abstract

En vue de commander plus précisément l'apport de chaleur introduit dans une pièce ouvrée (6) à assembler dans le cadre d'un processus d'assemblage par intervalle d'arc, une première durée de pause (TP1) d'une première phase de pause (PP1) est déterminée pendant le processus d'assemblage par intervalle d'arc et, dans le cas où la première durée de pause (TP1) déterminée s'écarte d'une durée de pause cible (TPsoll) spécifiée, au moins un paramètre d'assemblage du processus d'assemblage par intervalle d'arc, qui influence les durées de pause des phases de pause (PP), est modifié afin de réduire un écart entre une deuxième durée de pause (TP2) d'une deuxième phase de pause (PP2), qui suit la première phase de pause (PP1) dans le temps, et la durée de pause cible (TPsoll) spécifiée par rapport à l'écart entre la première durée de pause (TP1) et la durée de pause cible (TPsoll).
EP24710415.1A 2023-03-13 2024-03-12 Commande de processus d'assemblage par intervalle Pending EP4652008A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP23161495.9A EP4431215A1 (fr) 2023-03-13 2023-03-13 Procede d'assemblage d'intervalles de reglage
PCT/EP2024/056510 WO2024189004A1 (fr) 2023-03-13 2024-03-12 Commande de processus d'assemblage par intervalle

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EP4652008A1 true EP4652008A1 (fr) 2025-11-26

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EP24710415.1A Pending EP4652008A1 (fr) 2023-03-13 2024-03-12 Commande de processus d'assemblage par intervalle

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FI46465C (fi) 1971-03-25 1973-04-10 Kemppi Oy Ohutlevyjen MIG- ja MAG-hitsausmenetelmä, joka estää jatkuvan hitsisau man liiallista kuumenemista ja laite sen toteuttamiseksi.
JP5974984B2 (ja) 2013-06-07 2016-08-23 株式会社安川電機 アーク溶接装置、アーク溶接システム及びアーク溶接方法
JP6890236B2 (ja) * 2016-09-05 2021-06-18 パナソニックＩｐマネジメント株式会社 アーク溶接制御方法
DE102017113620B4 (de) * 2017-06-21 2019-07-11 Carl Cloos Schweißtechnik Gesellschaft mit beschränkter Haftung Lichtbogenschweißverfahren und -anlage mit einer Impulslichtbogen-Betriebsphase und einer Kurzlichtbogen-Betriebsphase
EP3744460B1 (fr) 2018-01-24 2024-04-03 Panasonic Intellectual Property Management Co., Ltd. Procédé de commande de soudage à l'arc
JP7407398B2 (ja) * 2018-04-18 2024-01-04 パナソニックＩｐマネジメント株式会社 アーク溶接の制御方法

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CN120882519A (zh) 2025-10-31
EP4431215A1 (fr) 2024-09-18
WO2024189004A1 (fr) 2024-09-19

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