Arc welding system and arc welding method using such system

Abstract

The present application relates to an arc welding system (1) for welding two parts (P) to each other, comprising at least: a base (2) movable in an advancing direction (D) relative to a surface of one of the parts (P) to be welded; a holder (6) of a welding torch arranged to receive an arc welding torch (T) having a welding wire electrode (F); a first actuator (10) and a second actuator (11) for displacing the gripper (6) relative to the base (2) in a plane (Pt) substantially perpendicular to the direction of advancement (D) of the base (2) relative to the component (P) and in two different directions, neither parallel to the longitudinal axis (L) of the welding torch; and a control unit (20) configured to control the first and second actuators (10, 11) in a coordinated manner based on a trajectory to be imparted to the end (30) of the welding wire electrode (F).

Description

Technical Field

[0001] The present invention relates to the welding of components, in particular for use in the automotive, aerospace, civil engineering, marine, metal construction and railway industries.

[0002] More particularly, the present invention relates to a movable arc welding system suitable for use in various welding configurations. Background Art

[0003] In order to reduce the amount of material deposited when two components are welded to one another, it is known to reduce the opening angle of the bevel, in particular to a value of less than or equal to 40°.

[0004] In such a configuration, in order to obtain good penetration and limit the risk of weld defects, it is necessary to tilt the wire electrode of the welding torch so that the wire electrode is as close as possible to the normal of the bevel surface.

[0005] On current mobile welding carriages with an oscillating axis, the amplitude is limited due to the distance between the contact point and the rotation point, which limits the achievable tilt to 5°. This does not allow the welding wire to be correctly oriented on the metal sheet. Therefore, these welds are usually produced manually by experienced operators.

[0006] Similarly, to weld metal sheets at right angles, the actuator used to displace the welding torch currently must be manually and mechanically oriented prior to welding. Furthermore, during the welding operation, the welding torch is swung with its orientation maintained. Consequently, the wire electrode is oriented relatively far from the local normal at the end of the weld bead, which prevents achieving good weld penetration.

[0007] For these situations, it is known to use a welding torch with a specific geometry. However, this torch is only suitable for one type of weld. Therefore, the torch needs to be changed depending on the geometry of the weld to be produced, which makes the weld more complicated and increases the purchase and use costs.

[0008] There is a need for a movable welding system that can maintain good orientation of the wire electrode during the welding operation while making the system easier to use. Summary of the Invention

[0009] The present invention satisfies this need by an arc welding system for welding two components to one another, the arc welding system comprising at least:

[0010] a base movable in the direction of advancement relative to a surface of one of the parts to be welded,

[0011] - a holder for a welding torch, said holder being arranged to receive an arc welding torch having a wire electrode,

[0012] a first actuator and a second actuator for displacing the holder relative to the base in a plane substantially perpendicular to the direction of advancement of the base relative to the component and in two different directions, neither of which is parallel to the longitudinal axis of the torch, and

[0013] - a control unit configured to control the first actuator and the second actuator in a coordinated manner based on a trajectory to be imparted to the end of the wire electrode.

[0014] The invention makes it possible to perform welding on different geometries without having to manually modify the position of the first actuator and / or the second actuator beforehand. This makes it easier to install the system and limits the risk of poor torch positioning during the welding operation.

[0015] Furthermore, coordinated control of the first and second actuators allows for precise positioning of the welding torch so that the trajectory of the wire electrode and weld can be optimized.

[0016] The system also allows the use of standard welding torches, limiting equipment purchase costs. Furthermore, this limits the need for training on different types of equipment, as manual welding and system welding are performed using the same torch and even the same welding station.

[0017] "Displacing the holder relative to the base in a plane substantially perpendicular to the direction of advancement of the base relative to the component" should be understood to mean that the (one or two) actuators displace the welding torch completely in a plane substantially perpendicular to the direction of advancement, that is, the displacement of the welding torch by the (one or two) actuators will not cause the welding torch to move outside the said plane.

[0018] "Substantially perpendicular to the plane of the base relative to the direction of advancement of the component" is understood to mean that the normal of the plane forms an angle of less than 20°, preferably less than 10°, and more preferably less than 5° with the direction of advancement of the base relative to the component, an angle of 0° forming a completely perpendicular plane.

[0019] actuator

[0020] The holder of the welding torch may be connected to the first actuator and / or the second actuator via an offset arm.

[0021] The first actuator may be a linear or rotary actuator.

[0022] The second actuator may be a linear or rotary actuator.

[0023] The linear actuator(s) enable translational displacement of the holder of the welding torch.

[0024] In one embodiment, the first actuator is a linear actuator and the second actuator is a rotary actuator and enables rotation of the welding torch, preferably around an axis substantially parallel to the direction of advancement.

[0025] In another embodiment, the first actuator and the second actuator are linear actuators, the displacement directions of the linear actuators being preferably orthogonal to each other. In this case, the holder of the welding torch can be connected to the first actuator and / or the second actuator via an offset arm.

[0026] In another embodiment, the first actuator is a linear actuator, the second actuator is a rotary actuator and enables the welding torch to be preferably rotated around an axis substantially parallel to the forward direction, and wherein the system includes a linear third actuator that enables the welding torch to be shifted translationally, the shifting directions of the linear actuators preferably being orthogonal to each other.

[0027] The use of a rotary actuator enables the orientation of the welding torch to be adjusted during the welding operation, in particular to maintain the orientation of the welding torch as close as possible to the normal of the surface on which the weld is being made.

[0028] An “axis substantially parallel to the direction of advancement” is understood to be an axis which, at a given time, forms an angle with the direction of advancement of less than 20°, better still less than 10°, better still less than 5°.

[0029] If necessary, the rotary actuator is positioned on the holder of the welding torch, in particular at the end of the offset arm.

[0030] The control unit is preferably configured to control the first, second and third actuators in a coordinated manner based on the trajectory to be imparted to the wire electrode tip.Such coordinated control allows a large freedom of movement of the welding torch, which facilitates optimal orientation of the welding torch.

[0031] The first actuator, the second actuator, and, where appropriate, the third actuator may each have a motor and a position sensor.

[0032] One of the actuators can displace the first, middle gripper in a direction Y that is generally parallel to the plane of the base. Another actuator can be supported by the first, middle gripper and displace the second, middle gripper in a direction Z that is perpendicular to direction Y. A third actuator can be supported by the second, middle gripper and rotate the torch holder about an axis X that is perpendicular to axes Z and Y.

[0033] base

[0034] The base can be a movable carriage, a portal frame or a rotating column.

[0035] The base, in particular the carriage, can have wheels, in particular each having an axis of rotation perpendicular to the direction of travel, and / or rails, in particular motor-driven rails, for displacing the base along the components to be welded. The carriage can be displaced by rolling on the components to be welded, or on at least one guide rail, or even on a rack. If appropriate, the carriage can be guided against one of the components to be welded, in particular if this component is a reinforcement.

[0036] The base, and in particular the carriage, may have four motor-driven wheels, each of which can be controlled independently of the others to orient the base in a desired direction.

[0037] The base, in particular the carriage, can have at least one wheelset, or even two wheelsets, in particular a right wheelset and a left wheelset, which are independently driven by electric motors.

[0038] The use of wheels allows for trackless guidance, thus reducing the logistics required for installation.

[0039] The base may have gripping elements allowing an operator to grasp and transport the base, for example, with only one hand.

[0040] The base may include a power supply system, in particular a battery, which avoids the need for bulky external cables.

[0041] The base may have one or more magnets for holding it to one of the components to be joined by magnetic attraction.

[0042] Control and guidance

[0043] The control unit may be programmed to perform welding autonomously and / or semi-autonomously.

[0044] “Autonomous” should be understood to mean that the system is capable of welding without operator intervention.

[0045] “Semi-autonomous” is understood to mean that the system is capable of welding under the supervision of an operator who can issue commands to the system to correct certain displacement parameters for the base or the weld.

[0046] The control unit may have any processor (e.g. a microcontroller) and interfaces for interacting with its environment, such as one or more sensors, a power stage for controlling motors, a human machine interface (HMI), a transceiver for exchanging data with a wireless remote control.

[0047] If desired, the control unit can be removably mounted on the system, particularly on the base. In this case, the system can have a receiving area that has a series of connectors for the control unit to be mounted on the base.

[0048] The system may comprise a remote control, in particular a wireless remote control, preferably a remote control device, allowing an operator to remotely control the displacement of the base relative to the parts to be welded, in particular the advancement rate of the base, the displacement direction of the base, and / or welding parameters.

[0049] The remote control may also be configured to provide details about the geometry of the weld to be made.

[0050] The control unit can be configured to receive data about the geometry of the weld to be made via a user interface or a remote control, and the data can include the angle between the two parts, the opening angle of the bevel between the parts, the material of the parts, and / or the thickness of the parts. The control unit can be designed to automatically determine one or more operating parameters of the base and the actuator based on the received data.

[0051] The system may include a transceiver that communicates with the remote control and is contained within the control unit or is separate.

[0052] The system may comprise a guide device, in particular a guide device comprising at least one guide rail. The guide rail may be fastened to one of the components magnetically or in another manner.

[0053] The system may include a guide laser that forms a visual reference frame on the parts to be welded, in particular on the edge of the bevel of the weld joint, for guiding the base.

[0054] The system can include a component geometry sensor, in particular a profilometer, preferably a laser profilometer, which measures the contour of the component to be welded upstream of the welding torch in the displacement direction of the welding torch. The actuator can be automatically controlled based on the contour measured in this way.

[0055] The system may include a guidance camera. Guidance may be performed with or without reference lines placed on the part.

[0056] If desired, the control unit is configured to control the first actuator, the second actuator and the third actuator in a coordinated manner based on the trajectory to be imparted to the wire electrode end.

[0057] welding torch

[0058] The system may include a welding torch received by a welding torch holder.

[0059] The welding torch may be removably mounted on the welding torch holder.

[0060] The welding torch may be configured to feed a wire electrode during a welding operation.

[0061] The welding torch may be a standard welding torch that can be used for MAG or MIG welding.

[0062] The system may include one welding torch, or two or even more than two welding torches. In this case, for each welding torch, the system may include a holder for the welding torch, a first actuator, a second actuator, and an optional third actuator. Each welding torch may be offset from the other welding torches in the direction of travel.

[0063] welding station

[0064] The system may include a welding station, in particular a standard welding station that can be used for open arc welding operations. By "standard welding station" is meant a welding station typically used for open arc welding operations, such as those used for MAG or MIG type welding operations. Using a standard welding station can significantly reduce the cost of the system, as such stations are readily available on the market.

[0065] The welding station, also called a generator, can be fixed in position relative to the parts to be welded during displacement of the base.

[0066] In one variant, the station can be displaced relative to the component during the welding operation, in particular to a specific point as welding progresses. For example, the welding station can be placed in a first position, the base can be displaced a certain distance without moving the welding station, and the hose connecting the welding torch to the welding station can be deployed during this operation. The welding station can then be brought to a second position, closer to the base, and the welding operation can continue.

[0067] In another variant, the station itself can be equipped with wheels and continuously displaced during the welding operation, for example driven by the base or supported by transport means autonomously or controlled by the displacement of the base.

[0068] The welding station may have a filler metal reel for the wire electrode.For example, the welding material may be conveyed from the welding station to the welding torch via a guide present in the aforementioned hose.

[0069] The arc welding station can be a MIG (“metal inert gas”) and / or MAG (“metal active gas”) welding station (with the shielding gas flow activated), a tungsten inert gas (TIG) welding station, a submerged arc welding station, an electroslag welding station, a plasma arc welding station, or any other type of arc welding station.

[0070] The welding station may have a grounding clamp configured to be positioned on at least one of the components to be welded.

[0071] The welding station may have a control panel for controlling welding parameters, particularly voltage, current, arc mode and / or filler metal wire feed rate.

[0072] Welding methods

[0073] According to another aspect of the invention, the invention also relates to a method for welding two parts to each other using a system as described above, wherein the base is arranged to move continuously or intermittently relative to the parts to be welded,

[0074] And, while the base is moving and / or between moves:

[0075] -The welding torch generates an arc,

[0076] The welding torch is displaced by coordinated movement of the first and second actuators, thereby forming a weld bead.

[0077] The method according to the invention enables welding on different geometries to be performed with one and the same system, by means of the coordinated movement of the first actuator and the second actuator.

[0078] Specifically, coordinated movement of the first actuator and the second actuator allows the welding torch to be precisely positioned at any point within a plane substantially perpendicular to the direction of advancement adjacent to the weld area, so that the trajectory of the weld can be optimized.

[0079] The movement of the first and second actuators can be coordinated with the displacement of the base. In particular, they can vary based on the forward speed. For example, when the base slows down, the displacement speed of the first and second actuators can also slow down.

[0080] When the first actuator is a linear actuator and the second actuator is a rotary actuator, the welding torch can be displaced by coordinating the linear movement of the first actuator with the rotational movement of the second actuator, thereby enabling the welding torch to rotate relative to the component, in particular around an axis substantially parallel to the advancement direction.

[0081] The welding torch can be displaced by coordinated movement of a first actuator, a second actuator and a third actuator, one of which is preferably a rotary actuator and the other two are linear actuators.

[0082] The movement of the third actuator may also be coordinated with the displacement of the base.

[0083] The welding torch can be swung in a direction perpendicular to the forward direction.

[0084] The oscillation can be performed at a constant spatial frequency, in particular when the weld bead to be produced has a substantially constant geometry. In a variant, the oscillation frequency can be varied, in particular when the weld bead to be produced has a highly variable geometry.

[0085] The resulting weld bead may have straight sections.

[0086] The weld bead produced may have a curved portion, the radius of curvature of which may be constant or non-constant.

[0087] Preferably, when the system comprises a rotary actuator, the position of the actuator is varied during formation of the bend.

[0088] For example, a weld bead may have two curved portions with a straight portion extending between the two curved portions.

[0089] The curved portion of the weld bead may be produced after the straight portion of the weld bead.The direction of displacement of the linear actuator(s) relative to the component during formation of the curved portion is preferably opposite to the direction of displacement during formation of the immediately preceding straight portion.

[0090] Preferably, when the system comprises a linear actuator and a rotary actuator, the position of the rotary actuator, in particular the position of its centre of rotation relative to the aforementioned intermediate second clamp, changes during formation of the curved portion due to actuation of the linear actuator(s).

[0091] Coordinated movement of the first, second, and optionally third actuators can cause the torch to rotate relative to the component about an axis substantially parallel to the direction of advancement and passing through the end of the wire electrode, in particular without translational movement of the end relative to the component.

[0092] During formation of the weld bead, the wire electrode may form an angle of less than 70°, preferably less than 45°, relative to the normal of the surface to be welded, in particular the bevel, facing the end of the wire electrode.

[0093] A weld bead can be produced between the components, the cross section of the weld bead having straight sections and / or curved sections (particularly a curved section at each end of the straight section).

[0094] Weld beads can be produced that are straight, triangular, V-shaped, fir-tree shaped, curved, or any desired shape.

[0095] The control unit preferably coordinates the movements of the first, second and (as appropriate) third actuators such that the displacement of the wire electrode end is controlled to a predetermined trajectory of the wire electrode.

[0096] In order to control the displacement of the end of the wire electrode, the control unit may translate the reference system formed by the axis of the actuator to the end of the wire electrode.

[0097] When the first actuator and the second actuator are linear actuators, the transformation of the reference frame may be: the orthogonal reference frame formed by the displacement axes of the first actuator and the second actuator is transformed into an orthogonal reference frame centered on the end of the welding wire electrode (one of the axes of the reference frame coincides with the longitudinal axis of the welding wire electrode).

[0098] The transformation is preferably performed such that the axes of the reference frames before and after the transformation are comprised in the same plane, which plane is preferably substantially perpendicular to the direction of advancement.

[0099] For example, when the first actuator and the second actuator are linear actuators, in order to shift the wire electrode a distance Δ in a moving direction orthogonal to the longitudinal axis of the wire electrode and the advancing direction, and if α is the minimum angle between the moving direction of the wire electrode and the displacement axis of the second actuator, the first actuator will shift a distance equal to the product of Δ and the sine of α, and the second actuator will shift a distance equal to the product of Δ and the cosine of α.

[0100] For example, when the first actuator is a linear actuator and the second actuator is a rotary actuator, if L is the distance between the end of the wire electrode and the second actuator, then the displacement distance Δ of the end of the wire electrode along the axis of the first linear actuator is equal to the sum of the displacement of the first actuator, the product 2L, and the cosine of the rotational half-angle of the second actuator. Therefore, for zero displacement of the end of the wire electrode along the axis of the first actuator, and for a given angular amplitude of the wire electrode (which is therefore equal to the rotational amplitude of the second actuator), the amplitude of the displacement of the first actuator can be inferred. Similarly, for welding with the wire electrode in a given orientation, i.e., with the second actuator in a fixed angular position, and the amplitude of the displacement of the end of the wire electrode is Δ, the amplitude of the movement of the first actuator can be inferred.

[0101] For example, for a linear first actuator, a linear second actuator and a rotational third actuator, in order to rotate the welding torch around the end of the wire electrode by an angle β, if α is the minimum angle between the displacement axis of the second actuator and the axis orthogonal to the longitudinal axis of the wire electrode in a plane perpendicular to the direction of advance before rotation, and if L is the distance between the end of the wire electrode and the third actuator, the first actuator will be displaced by L(sin(α+β)-sin(α)), the second actuator will be displaced by L(cos(α)-cos(α+β)), and the third actuator will be rotated by angle β.

[0102] Preferably, during the welding operation, the displacement axis of one of the actuators, in particular the first actuator, is parallel to one of the components.

[0103] Parts to be welded

[0104] The two components can form different angles with respect to one another, in particular an angle of approximately 90° or approximately 180°.

[0105] The components may have bevels between them, which form an opening therebetween with an angle less than or equal to 100°, in particular an opening with an angle less than or equal to 60°, for example less than or equal to 40°.

[0106] There may be an inclined surface between these parts, and the inclined surface has a protrusion at the lower portion.

[0107] These components may be metallic, in particular comprising stainless steel or non-stainless steel, aluminium or one of their alloys.

[0108] These components may be sheet metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0109] The present invention may be better understood by reading the following detailed description of non-limiting implementation examples of the invention and by examining the accompanying drawings, in which:

[0110] [ Figure 1 ] Figure 1 Schematically shows a front view of an example of a system according to the invention positioned on a flat component to be welded,

[0111] [ Figure 2 ] Figure 2 is similar to Figure 1 A view showing a system during the welding method according to the present invention,

[0112] [ Figure 3 ] Figure 3 Shown Figure 2 Progress in welding methods,

[0113] [ Figure 4 ] Figure 4 Schematically shows a front view of another example of a system according to the invention positioned on parts to be welded, forming a right angle between them,

[0114] [ Figure 5 ] Figure 5 yes Figure 4 According to the enlarged view of V,

[0115] [ Figure 6 ] Figure 6 is similar to Figure 5 A view showing the formation of the straight portion of the weld bead,

[0116] [ Figure 7 ] Figure 7 is similar to Figure 5 A view showing the formation of the curved portion of the weld bead, and

[0117] [ Figure 8 ] Figure 8 Schematically shows Figure 7 Top view of the system in . DETAILED DESCRIPTION

[0118] In the rest of the specification, the same or functionally identical elements have the same reference numerals. For the sake of brevity of this specification, the elements in each drawing are not described, but only the differences between the embodiments are described.

[0119] For the sake of clarity, the drawings are not always drawn to scale.

[0120] Figure 1 An example of a system 1 for welding two components P to each other is shown.

[0121] The system comprises a base, in this example a carriage 2 , which is arranged to be displaced in an advancement direction D over a surface of one of the parts P.

[0122] In this example, the carriage 2 has wheels 4 (four wheels in this example, Figure 1 Platform 3 on which only two wheels are visible.

[0123] Each wheel 4 is a driving wheel.

[0124] The system 1 includes a holder 6 for an arc welding torch T having a wire electrode F.

[0125] The welding torch T is, for example, a standard welding torch for MIG or MAG welding, a TIG welding station, a submerged arc welding station, an electroslag welding station, a plasma arc welding station, or any other type of arc welding station.

[0126] In this example, the welding torch T is connected to a standard welding station, which is not shown for the sake of clarity of the drawing.

[0127] The system 1 also comprises a linear first actuator 10 mounted on the platform 3 , connected by an offset arm 15 to a rotary second actuator 11 , itself connected to the holder 6 of the welding torch T.

[0128] The first actuator 10 enables the arm 15 and therefore the second actuator 11 , the gripper 6 and the welding torch T to be displaced in translation relative to the carriage 2 along a direction Y orthogonal to the normal to the surface of the base 3 .

[0129] The axis Y is not parallel to the longitudinal axis L of the welding torch T.

[0130] The second actuator 11 has an axis of rotation X parallel to the direction of advancement D.

[0131] The two actuators 10 and 11 operate together with motors and position sensors.

[0132] The system 1 further comprises a control unit 20 configured to control the first actuator 10 and the second actuator 11 in a coordinated manner based on a trajectory to be imparted to the end 30 of the wire electrode F.

[0133] The control unit 20 enables welding to be performed autonomously or semi-autonomously.

[0134] In this example, the control unit 20 is removably mounted on a receiving area on the platform 3 .

[0135] The control unit 20 also has a rechargeable battery for supplying power to itself and the actuators 10 and 11 .

[0136] The system 1 comprises a wireless remote control 21 which communicates with the control unit 20 via a transceiver system or via a wired connection when it is placed on top.

[0137] The remote control 21 forms a user interface allowing an operator to remotely control and possibly correct the displacement of the carriage 2 .

[0138] The remote control 21 also enables the input of data concerning the geometry of the weld to be made, such as the angle between the parts P, the thickness of the parts P, or the angle of the bevel between the parts P.

[0139] In this example, the system 1 includes a laser profiler 22 that measures the profile of the part P upstream of the welding torch T in the advancement direction D of the welding torch T.

[0140] Figure 2 and Figure 3 A first example of a welding method using the above-described system 1 is shown.

[0141] In this first example, the parts P are all lying flat. These parts each have an inclined surface forming an opening between them, the opening having an angle Oc of 40°.

[0142] In a first step, the system 1 is positioned on the outer surface of one of the parts P. Then, using the remote control 21 , for example, the user sends information about the geometry of the part P to the control unit 20 .

[0143] Then, the welding torch T is shifted to a position for welding operation.

[0144] Then, the carriage 2 starts to move in the direction D, and simultaneously, the wire electrode F generates an arc with one of the components and is fed through the welding torch T to form a weld bead J. In this example, the base 2 is displaced continuously or intermittently.

[0145] The first actuator 10 and the second actuator 11 displace the welding torch T to form the weld bead J using coordinated movement controlled by the control unit 20 .

[0146] like Figure 2 As shown, the two actuators 10 and 11 are displaced so that the longitudinal axis L of the wire electrode F remains close to the normal N facing the surface of the end 30 of the wire electrode F. In this example, the longitudinal axis L of the welding torch T forms an angle Os with the normal N that is less than 15°.

[0147] In order to produce the weld bead J, the welding torch T is displaced so that it performs an oscillation orthogonal to the direction D. During this oscillation, the orientation of the welding torch T is modified using the coordinated movement of the two actuators 10 and 11 so that the longitudinal axis L of the wire electrode F remains as close as possible to the normal N of the surface on which the weld bead J is formed.

[0148] in this regard, Figure 3 The position of the welding torch T after the first oscillation from left to right is shown. In this position, and during the oscillation, the angle Os remains less than 15°.

[0149] This orientation is maintained by the coordinated movement of the two actuators 10 and 11 .

[0150] For example, when the welding torch T is Figure 2 Move to the left position in Figure 3 In the right position in FIG, the first actuator 10 is displaced from left to right along the axis Y and the second actuator 11 is rotated counterclockwise about the axis X relative to the direction D. In a variant, the first actuator 10 may be fixed in position.

[0151] During the oscillation process, this orientation of the wire electrode F allows the wire electrode F to have good impact, good welding penetration, and thus good adhesion. This makes it possible to obtain a weld bead J with good geometry and no or few defects.

[0152] During the displacement of the carriage 2, for example, it oscillates from right to left and then from left to right until welding is complete. In this example, the oscillating movement, and therefore the movement of the two actuators 10 and 11, is coordinated with the displacement of the carriage 2, thereby achieving an oscillation with a relatively constant frequency. The wire feed rate of the welding wire electrode F can be coordinated with the oscillation speed and / or displacement speed of the carriage 2.

[0153] Figures 4 to 7 A variant of the system and method is shown in which two parts P form a right angle between them and the system comprises three actuators 10 , 11 and 12 .

[0154] In this example, the first actuator 10 and the second actuator 11 are identical to the previous examples. The first actuator 10 also enables a translational displacement of the third actuator 12.

[0155] In this example, the third actuator 12 enables the arm 15 and therefore the second actuator 11 , the gripper 6 and the welding torch T to be displaced in translation relative to the carriage 2 along a direction Z orthogonal to the surface of the platform 3 and perpendicular to the direction of advancement D.

[0156] In this example, the weld bead J to be produced has a substantially triangular cross-section in a plane perpendicular to the direction of advancement D.

[0157] As shown, the displacement axis Y of the first actuator 10 and the displacement axis Z of the third actuator 12 are orthogonal to each other, included in a plane perpendicular to the advancement direction D, and not parallel to the longitudinal axis L of the welding wire F of the welding torch T.

[0158] As mentioned above, the rotation axis X of the second actuator 11 is parallel to the advancement direction D.

[0159] In this example, the base 2 is set in intermittent motion.

[0160] exist Figure 5 Given in Figure 4 The partially enlarged view of FIG. 1 shows the oscillation trajectory Tb traveled by the end portion 30 of the wire electrode F during the welding operation.

[0161] This trajectory Tb has a straight portion Tb1 and two curved portions Tb2 and Tb3.

[0162] The oscillation is performed periodically, for example, first generating the curved portion Tb2, then generating the straight portion Tb1, then generating the curved portion Tb3, then generating the straight portion Tb1 again, etc. This oscillation is preferably performed when the bracket 2 is displaced.

[0163] It is also possible to extend the wire electrode F into the middle of the straight portion Tb1 to form a "fir-tree-shaped" weld.

[0164] To generate the straight line portion Tb1, as Figure 6 As shown, the linear actuators 10 and 12 are actuated while the orientation of the rotary actuator 11 remains unchanged.

[0165] The displacement of the third actuator 12 along the axis Z results in a displacement Z1 of the end 30 of the torch T. In this example, the displacement of the third actuator 12 along Z is equal to the product of the magnitude of Dt and the sine of the smallest angle α between Dt and the axis Z.

[0166] The angle α also corresponds to the minimum angle between the axis Z and an axis orthogonal to the longitudinal axis L of the wire electrode F in a plane perpendicular to the advancement direction D.

[0167] The displacement of the actuator 10 along the axis Y results in a displacement Y1 of the end 30 of the torch T. In this example, the displacement of the first actuator 10 along Y is equal to the product of the modulus of Dt and the cosine of the angle α.

[0168] The sum of the displacements along the axes Z1 and Y1 results in a displacement Dt of the end 30 of the torch T in a plane perpendicular to the direction of advancement D.

[0169] During the formation of the straight portion, the second actuator 11 is also displaced in the direction Dt.

[0170] As shown, during the formation of the straight portion Tb1 , the longitudinal axis L of the wire electrode F coincides with the normal N to the surface where the weld is produced, in the present case the surface of the formed portion of the weld bead J.

[0171] Figure 7 It is shown in Figure 6 The formation of the straight portion Tb1 is followed by the formation of the curved portion Tb2.

[0172] To form the bent portion Tb2 , welding is performed by rotating the wire electrode F around an axis X1 parallel to the advancing direction D and passing through the end portion 30 of the wire electrode F, the axis X1 being located at the center of curvature of the bent portion Tb1 .

[0173] Therefore, in order to form the curved portion Tb2, the end portion 30 may only be displaced in rotation. For example, the end portion 30 does not have any translational movement. In a variant, there may be a slight translational movement.

[0174] This rotation about the end portion 30 requires linear movement of the first actuator 10 and the third actuator 12 along the axes Z and Y in directions opposite to the movement during the formation of the straight portion Tb1 .

[0175] During the formation of the bent portion Tb2, the second actuator 11 rotates about the axis X in the same direction as the end portion 30 rotates about the axis X1.

[0176] exist Figure 7 , axis F1 is an axis orthogonal to the longitudinal axis L of the wire electrode F in a plane perpendicular to the advancing direction D before rotation, and axis F2 shows the longitudinal axis L of the wire electrode F before rotation.

[0177] As shown in the figure, in order to form the curved portion, the wire electrode F is rotated by an angle β relative to the axis F2.

[0178] To perform this rotation, the third actuator 12 has been displaced by L0 (sin(α+β)-sin(α)) along the axis Z, the first actuator 10 has been displaced by L0 (cos(α)-cos(α+β)) along the axis Y, and the second actuator has been rotated by angle β around X, where L0 is the length between the end 30 and the second actuator 11.

[0179] The different movements of the linear actuators 10 and 12 also result in a linear displacement of the second actuator 11 relative to the part P in the direction Dt1 .

[0180] This specific movement of the welding torch T around the end portion 30 makes it possible to keep the longitudinal axis L of the wire electrode F as close as possible to the normal N of the surface facing the end portion 30 .

[0181] For example, in this case, the angle Os is smaller than 10°.

[0182] A similar process is used to create the bent portion Tb3, but with a different displacement or rotation direction opposite to that during formation of the bent portion Tb2.

[0183] These movements of the three actuators 10 , 11 and 12 are coordinated by the control unit 20 during the formation of the various parts.

[0184] In particular, the control unit 20 coordinates these movements so that the displacement of the end portion 30 of the wire electrode F is controlled to follow its predetermined trajectory.

[0185] exist Figure 8 In the variant shown, the actuators 10 , 11 and 12 make it possible to displace the torch T in a plane Pt whose normal Nt forms an angle Ot of 5° with respect to the direction of advancement D, called the thrust angle.

[0186] In a variant not shown, the angle Ot can be reversed, ie the welding torch T is slightly pointed in the direction of advancement D.

[0187] The invention that has just been described is not limited to the examples that have just been described.

[0188] In particular, the angle between the parts P may be opened or closed differently, for example within a range between 0° and 360°.

[0189] The cross section of the weld bead J may have a plurality of (eg, 1 to 4) different bends.

[0190] The weld bead J may have a plurality (eg, 1 to 4) of different straight sections.

[0191] The movements of the three actuators 10 , 11 and 12 can be coordinated so that the bend is formed by the rotation of the welding torch T about the end 30 and the translational movement of this end.

[0192] The movement of the actuators 10 , 11 and 12 can be produced in a plane whose normal forms an angle of less than 20° with the direction of advancement.

Claims

1. An arc welding system (1) for welding two parts (P) to each other, comprising at least: a base (2) movable in an advancement direction (D) relative to a surface of one of the parts (P) to be welded, - a holder (6) for a welding torch (T), said holder being arranged to receive an arc welding torch (T) with a wire electrode (F), a first actuator (10) and a second actuator (11) for displacing the holder (6) relative to the base (2) in a plane (Pt) substantially perpendicular to the direction of advancement (D) of the base (2) relative to the part (P) and in two different directions, neither of which is parallel to the longitudinal axis (L) of the welding torch, and - a control unit (20) configured to control the first actuator (10) and the second actuator (11) in a coordinated manner based on a trajectory to be imparted to the end (30) of the wire electrode (F).

2. The system (1) as claimed in claim 1, wherein The first actuator (10) is a linear actuator and the second actuator (11) is a rotary actuator and enables the welding torch (T) to be rotated preferably about an axis (X) substantially parallel to the advancement direction (D).

3. The system (1) as claimed in claim 1, wherein The first actuator (10) and the second actuator (11) are linear actuators, and the displacement directions (Y, Z) of the linear actuators (10, 11) are preferably orthogonal to each other.

4. The system (1) as claimed in claim 1, wherein The first actuator (10) is a linear actuator, the second actuator (11) is a rotary actuator and enables the welding torch to be preferably rotated around an axis (X) substantially parallel to the advancement direction (D), and wherein the system includes a linear third actuator (12) that enables the welding torch (T) to be shifted translationally, the shifting directions (Y, Z) of the linear actuators (10, 12) preferably being orthogonal to each other.

5. A system as claimed in any one of the preceding claims, wherein: The base (2) is a movable bracket, a portal frame or a rotating column.

6. System (1) according to any one of the preceding claims, wherein The base (2) has wheels (4), in particular each wheel having an axis of rotation perpendicular to the advancement direction (D), and / or rails, in particular motor-driven rails, for displacing the base along the part (P) to be welded.

7. A system (1) as claimed in any one of the preceding claims, comprising at least one geometry sensor (22) for the part (P), which measures the contour of the part (P) to be welded upstream of the welding torch (T) in the displacement direction of the welding torch (T), and the actuator (10, 11, 12) can be automatically controlled based on the contour measured thereby.

8. The system (1) according to any one of the preceding claims, comprising a welding torch (T) received by a holder (6) of the welding torch (T).

9. A method for welding two components (P) to each other using a system (1) as claimed in any one of the preceding claims, wherein: The base (2) is arranged to move continuously or intermittently relative to the part (P) to be welded, And, while the base (2) is moving and / or between two movements: - said welding torch (T) generates an arc, - The welding torch (T) is displaced by the coordinated movement of the first actuator (10) and the second actuator (11), thereby forming a weld bead (J).

10. The method according to the preceding claim, wherein The movement of the first actuator (10) and the second actuator (11) is coordinated with the displacement of the base (2).

11. The method according to any one of claims 9 and 10, wherein When the first actuator (10) is a linear actuator and the second actuator (11) is a rotary actuator, the welding torch (T) is displaced by coordinating the linear movement of the first actuator (10) with the rotary movement of the second actuator (11), so that the welding torch (T) can be rotated relative to the part (P), in particular around an axis (X) that is substantially parallel to the forward direction (D).

12. The method according to any one of claims 9 to 11, wherein The welding torch (T) is displaced by the coordinated movement of the first actuator (10), the second actuator (11) and the third actuator (12), one of which is preferably a rotary actuator and the other two actuators (10, 11, 12) are linear actuators.

13. The method according to any one of claims 9 to 12, wherein The welding torch (T) is swung in a direction perpendicular to the advancing direction (D).

14. The method according to any one of claims 9 to 13, wherein The weld bead (J) produced has straight sections and / or curved sections.

15. The method according to any one of claims 9 to 14, wherein The curved portion (Tb2, Tb3) of the weld bead (J) is produced after the straight portion (Tb1) of the weld bead (J), and the displacement direction of the linear actuator (10, 11) relative to the component during the formation of the curved portion (Tb2, Tb3) is opposite to the displacement direction during the formation of the immediately preceding straight portion (Tb1).

16. The method according to any one of claims 9 to 15, wherein Coordinated movement of the first actuator (10), the second actuator (11), and, as the case may be, the third actuator (12) causes the welding torch (T) to rotate relative to the part (P) about an axis (X1) substantially parallel to the advancement direction (D) and passing through the end (30) of the wire electrode (F).

17. The method according to any one of claims 9 to 16, wherein During the formation of the weld bead (J), the wire electrode (F) forms an angle (Os) of less than 70°, preferably less than 45°, relative to the normal (N) of the surface to be welded facing the end (30) of the wire electrode (F).

18. The method according to any one of claims 9 to 17, wherein A weld bead (J) is produced between the parts (P), the cross section of the weld bead (J) having a straight portion (Tb1) and curved portions (Tb2, Tb3), in particular two curved portions (Tb2, Tb3) at each end of the straight portion (Tb1).

19. The method according to any one of claims 9 to 18, wherein The control unit (20) coordinates the movement of the first actuator (10), the second actuator (11) and, if appropriate, the third actuator (12) so that the displacement of the end (30) of the wire electrode (F) is controlled by a predetermined trajectory of the wire electrode (F).

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