Arc welding system

Abstract

Arc Welding System (1) Arc welding system comprising: A movable base (6), having at least one magnetic element (10) capable of producing, by magnetic attraction, a force to hold the base on the surface over which it moves; at least one arc welding torch (4), preferably standard such as used for MAG or MIG welding, mounted on the base (6) and connected to a welding station (2); a flux distribution assembly (15), removably mounted on the base to submerge the arc with flux, this assembly comprising: a flux reservoir (16); at least one flux distribution nozzle (24); and at least one flux suction nozzle (23). Figure for abbreviation: Fig. 1

Description

Title of the invention: Arc welding system technical field

[0001] The present invention relates to the welding of parts, in particular for the automotive, aeronautical, civil engineering or naval industries.

[0002] The invention relates in particular to mobile submerged arc welding (SA) systems. Previous technique

[0003] To carry out the welding of parts, in particular metallic parts, it is known to use an arc welding system.

[0004] Conventional arc welding processes, such as MAG or MIG, are open-arc processes that produce fumes and UV radiation, requiring special precautions to protect the operator. In these processes, the filler metal is supplied in the form of welding wire, which acts as a consumable electrode, and is unwound from a spool. An inert gas is sprayed onto the weld area to protect the weld pool.

[0005] Submerged arc welding is a known method. In this technology, the arc is submerged under a solid flux in powder form. Submerged arc welding offers the advantage of reducing, or even completely eliminating, fume emissions, of having an arc that is at least partially, or even completely, obscured by the flux, making it invisible, and is less sensitive to air currents.

[0006] This technology is suitable for welding in enclosed or open environments, for example outdoors on a shipyard. It produces a high-quality weld with high productivity.

[0007] Submerged arc welding is mechanized, but this mechanization is often simple and robust. Indeed, known installations for performing submerged arc welding are mounted on a gantry or a generally heavy trolley, the weight of which contributes to the trolley's stability. They typically weigh over 40 kg and require handling equipment for transport, thus complicating their use. The process is limited to flat or ledge welding positions.

[0008] Furthermore, these installations are specific to submerged arc welding and are only suitable for this type of welding. For example, tack welding of sheet metal is not possible with such an installation. Therefore, it is often necessary to have, in addition to a submerged arc welding installation, another welding installation, for example MIG or MAG. Thus, the investment required to acquire a submerged arc welding installation is relatively significant, which can limit its use.

[0009] These trolley-type installations require, due to the weight of the assembly, the mounting of guides for guidance, which further complicates the operation.

[0010] In addition, the time required to perform the welding, i.e. the positioning of the heavy trolley, the guides, the movement of the trolley, the removal of the guides and the removal of the trolley, is significant, thus reducing the production yield.

[0011] There is a need to remedy all or part of the disadvantages of the prior art and in particular to have a solid flux welding system which is simple to use, if desired portable by an operator, quick to set up, while limiting the investment dedicated to be made and which is capable of producing a good quality weld. Description of the invention

[0012] The present invention meets this need by means of, according to one of its aspects, an arc welding system comprising: - A mobile base, comprising at least one magnetic element capable of producing, through magnetic attraction, a force to hold the base onto a surface on which it moves, - at least one arc welding torch, preferably a standard one such as used for MAG or MIG welding, mounted on the base and connected to a welding machine, - a flow distribution assembly, removably mounted on the base to submerge the arc with the flow, this assembly comprising: o a flow reservoir, o at least one flow distribution nozzle, and o at least one flow suction nozzle.

[0013] The system can thus perform, depending on the presence or absence of the distribution assembly, or whether or not it is functioning, a non-submerged or submerged weld.

[0014] The welding torch, the magnetic element and the flux distribution assembly are moved by the base during the welding operation.

[0015] The system according to the invention allows for a relatively lightweight submerged arc welding system, compared to the prior art, without sacrificing stability thanks to the use of the magnetic element. Thus, thanks to the invention, it is possible to achieve a high-quality submerged arc weld, while having a system that is easy to use and handle.

[0016] The system also allows for non-submerged welding, i.e., open arc welding, by deactivating the distribution assembly, or even by removing it from the base. Thus, the system according to the invention allows for submerged or non-submerged welding. submerged, depending on the needs, with the same equipment, thus reducing the need for investment and the need for operator training.

[0017] The moving part of the system may weigh less than 30 kg, preferably less than 20 kg, for example 15 kg, thus avoiding the need for a handling system such as a hoist or similar device. The holding force provided by the magnetic element may exceed 10 kg, in particular exceeding 25 kg. The magnetic element may comprise one or more rare-earth permanent magnets.

[0018] The welding torch is connected to a welding station, which provides, in particular, the electric current necessary for generating the arc.

[0019] Finally, the removable nature of the flux distribution assembly allows it to be offered as an accessory to the base, which can then be used in combination with a different accessory, or without any accessory, to perform, for example, MAG or MIG welding. Thus, the investment required for a user who already owns the base, for example, to perform another type of process, or a welding machine, for example a standard MIG or MAG machine for another application, to be able to perform submerged arc welding, is reduced, since only the purchase of the flux distribution assembly is then necessary.

[0020] The welding system can be used on parts positioned horizontally or forming an angle with the horizontal of less than 15°. The welding system can allow parts forming a cornice to be welded together. Welding torch

[0021] The welding torch can be removably mounted on the base.

[0022] The torch can be configured to feed a welding material during welding, including a welding wire.

[0023] The torch can be configured to cut, during welding, an electrode wire, this electrode wire having in particular a diameter between 0.2 mm and 2 mm, for example 1.6 mm or 2 mm.

[0024] The welding torch can be a standard torch usable for MAG or MIG welding.

[0025] The system may include one or two, or even more than two, welding torches. The use of two welding torches allows the use of smaller diameter welding wires, while combining their effects. For example, each torch uses a 1.6 mm diameter welding wire, significantly smaller than the welding wires typically used in known submerged arc welding installations, which are typically 4 to 8 mm in diameter. Mobile base

[0026] The base can be a mobile trolley, a gantry or a rotating column.

[0027] The base may include a support on which at least some constituent elements of the flow distribution assembly are removably fixed, for example the flow reservoir.

[0028] The bracket can also be used to attach other system components to the base.

[0029] The base, in particular the carriage, may include wheels and / or tracks, including motorized ones, allowing it to move along the parts to be welded. The carriage may move by rolling on the parts to be welded, or on at least one guide rail, or even on a rack. The carriage may be guided, if necessary, by bearing against one of the parts to be welded, particularly when that part is a stiffener.

[0030] The base, in particular the trolley, may have four motorized wheels, each wheel being able to be controlled independently of the others in order to orient the trolley in the desired direction.

[0031] The base, in particular the carriage, may include at least one, or even two, wheel sets, in particular a right set and a left set, independently motorized.

[0032] The use of wheels allows for rail-free guidance and therefore limited installation logistics.

[0033] The base may include a gripping element enabling the operator to grasp and carry the base, for example with one hand.

[0034] The base may include a power supply system, in particular a battery. The use of a battery avoids the need for an external and cumbersome power cable.

[0035] When the parts to be welded are positioned vertically and the weld joint horizontally, a position known as the "cornice position," "2G position," or "PC position," the base can be positioned horizontally. In this case, the welding torch, suction nozzle, and dispensing nozzle can be located in the lower part of the system, with the flux reservoir positioned in the upper part of the system.

[0036] The system may include, in particular near the flux distribution and suction nozzles, an accessory for retaining the flux in the welding area, particularly when the parts are in a cornice position.

[0037] The accessory may be a platform comprising a conveyor belt, preferably moving at the same linear speed as the base. Preferably, the face of the conveyor belt intended to retain the flux moves in a direction opposite to the welding direction, in particular at an absolute speed identical to the absolute welding speed, so that the face of the conveyor belt intended to retain the flux is fixed relative to the parts to be welded and therefore to the weld.

[0038] The base may include an arm for attaching, in particular in a removable and adjustable manner, the welding torch. The base, in particular the arm, may also allow, where appropriate, for attaching, in particular in a removable and adjustable manner, the accessory for retaining the flux.

[0039] The position of the arm can be adjusted along several axes, in particular in translation along one, two or three axes, and / or in rotation.

[0040] The base can carry various components necessary for the operation of the system, including at least one rechargeable battery.

[0041] The welding station may not be carried by the base, being only connected by a flexible hose to the welding torch. Control and guidance

[0042] The system may include a control unit programmed to perform welding autonomously and / or semi-autonomously.

[0043] By "autonomously", it is meant that the system is capable of performing the welding without the intervention of an operator.

[0044] By "in a semi-autonomous manner", it is understood that the system is capable of performing the weld under the supervision of an operator, the operator being able to transmit orders to the system in order to correct certain parameters of displacement of the base or of the weld.

[0045] The control unit may include any processor, for example microcontroller and interfaces for interacting with its environment, for example sensor(s), power stage for motor control, HMI, transmitter / receiver for communicating with a wireless remote control.

[0046] The control unit may, where appropriate, be removably mounted on the system, in particular on the base. In this case, the system may include a receiving base with a series of connectors for mounting the control unit on the base.

[0047] The system may include a remote control, in particular wireless, preferably a remote control, allowing an operator to remotely control the movement of the base relative to the parts to be welded, in particular the feed speed of the base, the direction of movement of the base, and / or welding parameters.

[0048] The remote control can also be configured to allow control of the position of the arm carrying the welding torch.

[0049] The system may include a transceiver communicating with the remote control, included in the control unit or independent.

[0050] The system may include a guiding means, in particular comprising at least one guide rail. This guide rail may be fixed magnetically or otherwise to one of the parts.

[0051] The system may include a guidance laser forming a visual reference on the parts to be welded, in particular positioned on the edge of the chamfer of a welding cornice, to guide the base.

[0052] The system may include a profilometer, in particular a laser profilometer, measuring the profile of the parts to be welded upstream of the welding torch in the direction of its movement. Welding station

[0053] Preferably, the welding station is a standard welding station suitable for open arc welding. A "standard welding station" is defined as a welding station commonly used for open arc welding operations, for example, MAG or MIG welding, without flux immersion. Using a standard welding station significantly reduces the system cost, as this type of station is readily available commercially.

[0054] The welding station, also called the generator, can be fixed relative to the parts to be welded during the movement of the base.

[0055] Alternatively, the welding station can be moved relative to the workpieces during welding, particularly intermittently as the welding progresses. For example, the welding station is initially positioned, and the base is moved a certain distance without moving the welding station, the flexible hose connecting the welding torch to the welding station extending during this operation. The welding station can then be moved to a second position, closer to the base, and the welding operation continued.

[0056] In another variant, the station itself can be equipped with wheels and be moved continuously during welding, for example pulled by the base.

[0057] The welding station may include a spool of welding material. The welding material may be sent from the welding station to the welding torch through a guide, present within the aforementioned flexible hose, for example.

[0058] The welding station can be a MIG (in English "Metal Active Gas") and / or MAG (in English "Metal Active Gas") station, in which the protective gas flow is deactivated when using the flux.

[0059] The welding station may include a ground clamp configured to be positioned on at least one of the parts to be welded.

[0060] The welding station may include a control panel for controlling welding parameters, including electrical voltage, electrical current and / or the feed rate of the welding material. Removable flow distribution assembly

[0061] The flux may include manganese oxides, complex silicates of lime and / or alumina, in particular in powder form.

[0062] The flux can be a solid or molten flux.

[0063] The flow can be an agglomerated flow.

[0064] The flux can be basic or acidic.

[0065] Preferably, the flow is a solid flow.

[0066] The solid stream may include a calibrated and homogeneous size powder.

[0067] The flow drawn in by the suction nozzle can be returned to the flow reservoir, from preferably when cleaned and / or sifted.

[0068] The flow circulation in the flow distribution assembly can be ensured by compressed air, in particular from a compressed air supply to which the assembly is connected.

[0069] The removable assembly can be configured to distribute a linear flow rate between 0.1cm3 / mm and 20cm3 / mm.

[0070] The assembly may include means for drawing the flux from the flux reservoir and circulating it to the weld zone, as well as for suction and return to the reservoir. These means may include a separator, for example a cyclone separator, to separate the flux particles returned to the reservoir from the carrier gas, and an air injection system for injecting air into the reservoir to carry the flux particles to the weld zone. Carrier air may be returned to the atmosphere after filtration. Welding process

[0071] The invention also relates, according to another aspect, in combination with the foregoing, to a method of welding parts using a system according to the invention, as defined above, in which the base is moved relative to the parts to be welded, and, when the base is in motion: - The flux distribution system deposits flux onto the parts to be welded upstream of the torch, - the welding torch produces an arc, which is submerged in the flux thus deposited, - the flux distribution system recovers the excess flux downstream of the torch by suction.

[0072] When the base is moving, the welding torch, the distribution nozzle and the suction nozzle can be aligned in the direction of its movement.

[0073] The welding station can be fixed relative to the parts to be welded. Range of accessories

[0074] The invention also relates, according to another aspect, independently or in combination with the foregoing, to a range of accessories for an arc welding system comprising a base configured to move along parts to be welded, this range comprising: - a flux distribution assembly, configured to be removably attached to the base, to allow for submerged arc welding, - at least one welding torch, in particular a standard one such as used for MAG or MIG welding, which can be mounted removably on the base.

[0075] This range can be completed by the base itself, and by the remote control used to operate it. Brief description of the drawings

[0076] The invention will be better understood upon reading the detailed description that follows, a non-limiting example of its implementation, and upon examination of the accompanying drawing, in which

[0077] [Fig. 1] [Fig. 1] schematically and partially represents an example of a system according to the invention,

[0078] [Fig.2] [Fig.2] shows an elevation view of a detail of the system embodiment,

[0079] [Fig.3] [Fig.3] illustrates in perspective the execution of a submerged arc weld,

[0080] [Fig.4] [Fig.4] illustrates, in side view and schematically, an example of system for a cornice weld, and

[0081] [Fig.5] [Fig.5] illustrates, in perspective and schematically, an example of a system for a cornice weld. Detailed description

[0082] In the rest of the description, identical elements or elements with identical functions bear the same reference sign.

[0083] In the figures, the actual proportions have not always been respected, for the sake of clarity.

[0084] Figures 1 to 3 illustrate an example of an arc welding system 1 according to the invention for welding metallic parts P, for example steel sheets or a stiffener on a steel sheet.

[0085] The system includes a standard welding station 2, for example a MIG generator whose function of sending a protective gas flow has been cut off.

[0086] The welding station 2 is connected by a flexible hose 3 to a welding torch 4, for example a torch 4 used for MIG welding.

[0087] The welding station 2 may include a control panel 5 for adjusting the electrical voltage, electrical current, and feed rate of the welding material, in this example, an electrode wire, for example, 1.6 mm in diameter. The electrode wire can be unwound from a reel on the welding station 2 and guided to the torch 4 by a conduit in the flexible hose 3.

[0088] The torch 4 may include a trigger 7 allowing the operator to manually trigger the formation of the electric arc and the unwinding of the electrode wire.

[0089] The system 1 includes a trolley 6 which is arranged to move along the parts to be welded and which carries the torch 4.

[0090] This trolley 6 rests, for example, by means of motorized wheels 8, for example four in number, on at least one of the parts to be welded, but alternatively includes tracks or other means of drive, and can, where appropriate, travel on one or more rails installed on the parts or in their vicinity, or even on a rack.

[0091] The trolley 6 carries at least one magnetic element 10 in the form of one or more rare earth permanent magnets, which produces by magnetic attraction a force F to hold the trolley 6 on the surface on which it has been placed.

[0092] The magnetic element 10 advantageously produces a magnetic force F of a magnitude greater than the weight of the trolley 6 and its equipment. The force F is, for example, greater than or equal to 10 kg, the mass of the trolley and its equipment being advantageously less than or equal to 30 kg, preferably 25 kg.

[0093] The trolley 6 carries a solid flux distribution assembly 15, allowing the electric arc generated by the torch 4 to be submerged under the flux.

[0094] This assembly 15 is removably fixed on the carriage 6, in order to allow the carriage to be used without it, for example to carry out conventional open arc welding, of the MAG or MIG type in particular.

[0095] The assembly 15 includes a solid flow reservoir 16, which can be surmounted, for example, by a separator and / or filter 18.

[0096] The assembly 15 is connected to a compressed air supply 20, for example in the form of a flexible hose.

[0097] This power supply 20 can be connected to a venturi 21, disposed in the return circuit 22 of the flow to the separator 18.

[0098] The venturi 21 makes it possible to create a vacuum in the return circuit 22 and to draw in the flow particles from the inlet 23 of a suction nozzle.

[0099] The separator 18 allows the solid particles of the flow to be separated from the carrier gas, which can be released into the atmosphere as illustrated by the arrows, after passing through a filter.

[0100] The solid flux particles can, after separation from the carrier gas, fall into the reservoir 16.

[0101] The latter may have a truncated conical shape in the lower part, in order to channel the flux particles towards an outlet port connected by a conduit 29 to a distribution nozzle 24.

[0102] The reservoir 16 may include a tube 26 which plunges into it and allows compressed air to be brought close to the outlet port, in order to cause the flow of the flux particles and their entrainment in the conduit 29 to the distribution nozzle 24.

[0103] The system 1 may include a gantry 30, which supports the tank 16 and allows its attachment to the trolley 6.

[0104] This gantry 30 is fixed for example by one or more screws on a corresponding support provided on the carriage 6.

[0105] The torch 4 can be carried by an arm 31 which allows, for example, for it to be positioned precisely and with the desired orientation relative to the carriage 6.

[0106] Similarly, the flow distribution nozzles 24 and suction nozzles 23 can be mounted with a possibility of position adjustment, if necessary.

[0107] During the use of system 1, a circulation of solid flux can be established between nozzles 23 and 24, to maintain a cloud of solid flux 35 at the level of the arc generated by the torch 4, and thus achieve a submerged arc weld.

[0108] To use system 1, if the user already has the trolley 6 used without the assembly 15 to carry out MAG or MIG type welds, he simply needs to mount the assembly 15 on the trolley 6 and connect it to the compressed air supply 20.

[0109] The system 1 is advantageously controlled by a remote control 40, as illustrated in [Fig.1], which allows, for example, the adjustment of various operating parameters, such as the advance speed of the carriage, the direction of movement, the correction of the trajectory, or even the orientation of the torch 4 relative to the carriage 6.

[0110] Figure 3 shows the carriage 6 moving along the welding path.

[0111] It can be seen that the solid flow distribution nozzle 24 can be arranged upstream of the torch 4, relative to the direction of travel of the carriage, while the suction nozzle 23 is arranged downstream.

[0112] It can also be seen that the distribution nozzle 24 can be closer to the torch 4 than the suction nozzle 23.

[0113] The trolley 6 may include a removable control unit 60, which contains at least part of the electronics necessary for controlling the wheel motors, and more generally, for the operation of the system.

[0114] This control unit 60 can be received in a corresponding base of the trolley, equipped with electrical connectors allowing power supply and signal exchange.

[0115] The trolley 6 may also include a battery, which may also be removably mounted on it.

[0116] On [Fig.3], it can be seen that the carriage 6 can be equipped at the front with a laser pointer forming a visual reference on the parts P to be welded on the edge of the chamfer of the cornice 70 between the parts P.

[0117] The movement of the carriage 6 can be carried out, where appropriate, based on information provided by a sensor such as, for example, a profilometer used to acquire the profile of the parts to be welded, a camera, a laser pointer 38, or any other means of detecting and locating the ledge 70, in order, for example, to precisely follow the ledge 70 where the weld 71 is to be made. This movement can be carried out automatically or semi-automatically, the operator retaining, for example, the ability to modify the trajectory at any time.

[0118] Figures 4 and 5 illustrate a variant of a system for welding vertically arranged parts P with a horizontal cornice 70, called the "cornice position" or "2G" position or "PC". In Figures 4 and 5, a portion of system 1 has not been shown for the sake of clarity.

[0119] In this case, the trolley can move horizontally, for example on an adjacent platform. Thus, the torch 4, the suction nozzle 23 and the distribution nozzle 24 are, as in the previous example, in the lower part of system 1, the flux tank 16 being positioned in the upper part of system 1.

[0120] The system 1 may include, near the flux distribution nozzles 24 and suction nozzles 23, an accessory 100 for retaining the flux 35 in the welding zone.

[0121] As illustrated in [Fig.4](a), the accessory may include an L-shaped platform.

[0122] The accessory 100 is fixed to the arm 31.

[0123] As illustrated in Figures 4(b) and 5, the accessory 100 may include a conveyor belt 101 moving with the same linear speed as the trolley.

[0124] The face 102 of the conveyor belt 101 intended to retain the flux 35 moves in a direction T opposite to the direction D of welding, at an absolute speed identical to the absolute speed of welding so that the face 102 is fixed relative to the parts P to be welded and therefore to the cornice 70.

[0125] In this example, the conveyor belt 101 rotates around two axes 105, which may in particular be motorized.

[0126] Of course, the invention is not limited to the examples just described.

[0127] For example, two torches 4 can be mounted on the trolley, operating simultaneously, for example, both with submerged arc, the assembly being adapted in this case to distribute the solid flux to each of the torches individually or together. These two torches can be installed side by side or one behind the other, or even offset, depending on the configuration of the joint to be welded.

[0128] For example, the system may include a guiding means comprising at least one guide rail, for example a rail parallel to the cornice.

Claims

Demands

1. Arc welding system (1), comprising: - A mobile base (6), having at least one magnetic element (10) capable of producing by magnetic attraction a force for holding the base on the surface on which it moves, - at least one arc welding torch (4), preferably standard such as used for MAG or MIG welding, mounted on the base (6) and connected to a welding station (2), - a flux distribution assembly (15), removably mounted on the base to submerge the arc with flux, this assembly comprising: o a flux reservoir (16), o at least one flux distribution nozzle (24), and o at least one flux suction nozzle (23), the flux distribution and suction nozzles (24, 23) being mounted with a possibility of position adjustment.

2. System according to claim 1, the holding force provided by the magnetic element (10) being greater than 10 kg, better greater than or equal to 25 kg.

3. System according to any one of claims 1 and 2, the welding station (2) being a standard welding station usable for an open arc welding operation, in particular of the MAG or MIG type.

4. System according to the preceding claim, the welding torch (4) being removably mounted on the base (6).

5. System according to any one of the preceding claims, the torch (4) being configured to cut, during welding, an electrode wire having a diameter between 0.2 mm and 2 mm, preferably 1.6 mm or 2 mm.

6. System according to any one of the preceding claims, the welding torch (4) being a standard torch usable for MAG or MIG welding.

7. System according to any one of the preceding claims, the base (6) comprising wheels (8), in particular motorized, enabling its movement along the parts to be welded.

8. System according to any one of the preceding claims, comprising a guiding means, including in particular at least one guide rail.

9. A system according to any one of the preceding claims, comprising a remote control, in particular wireless, preferably a remote control (40), enabling an operator to remotely control the movement of the base relative to the parts to be welded, in particular the feed speed of the base, the direction of movement of the base, and / or welding parameters.

10. System according to any one of the preceding claims, wherein the welding station (2) is fixed relative to the parts to be welded during the movement of the base (6).

11. System according to any one of the preceding claims, wherein the flow circulation in the assembly (15) is ensured by compressed air, in particular from a compressed air supply (20) to which the assembly (15) is connected.

12. System according to any one of the preceding claims, comprising an accessory (100) for retaining the flux (35) in the weld zone, particularly when the parts are in a cornice position.

13. System according to the preceding claim, wherein the accessory (100) is a platform comprising a conveyor belt (101).

14. A method of welding parts using a system (1) as defined in any one of the preceding claims, wherein the base (6) is moved relative to the parts to be welded, and, when the base is moving: - the flux distribution assembly (15) distributes flux onto the parts to be welded, - the welding torch produces an arc, the latter being immersed in the flux thus distributed, - the flux distribution assembly (15) recovers the flux by suction.

15. A range of accessories for an arc welding system comprising a base (6) configured to move along parts to be welded, this range comprising: - A flux distribution assembly (15), configured to be removably attached to the base (6), in order to allow submerged arc welding, this assembly comprising: o a flux reservoir (16), o at least one flux distribution nozzle (24), and o at least one flux suction nozzle (23), the flux distribution and suction nozzles (24, 23) being mounted with a position adjustment capability, - at least one welding torch (4) which can be removably mounted on the base (6).