Machine tool implementing a friction stir welding method, working method thereof and friction stir welding tool

Abstract

The invention relates to a machine tool that is characterised in that it accommodates and rotates a friction stir welding tool (500) comprising a first friction stir welding end (510) with a rotating pin (511) and a rotating shoulder (512), the force required to carry out a friction stir welding method being measured and maintained for the purpose of creating force feedback during contact between the tool (500) and the parts to be joined via the functionality of controlling and monitoring the force during a movement up to a fixed stop. The invention also relates to the working method and to the tool for carrying out friction stir welding operations.

Description

Description Title of the invention: Machining machine tool implementing a friction stir welding process, its working method and friction stir welding tool

[0001] FIELD OF APPLICATION OF THE INVENTION

[0002] The present invention relates to the field of friction welding and in particular to adaptations enabling a machining machine tool to implement such a process under the best conditions,

[0003] DESCRIPTION OF THE PRIOR ART

[0004] Friction stir welding, also known as FSW, is a welding process that involves joining two parts by bringing their contacting surfaces into a paste-like state using a specially designed rotating tool.

[0005] This tool typically includes a shoulder and a coaxial pin which, when applied and rotated, locally bring the parts to be assembled into a pasty state. The tool is applied and rotates on the contact line between the two parts to be assembled or by crossing the first thickness to weld it to the second for two superimposed parts.

[0006] This tool penetrates the softened materials and kneads them to mix them thoroughly.

[0007] The assembly is obtained by the progression of the rotating tool, which follows the desired contact line or trajectory.

[0008] It is understood that the implementation of this process requires that the tool exerts a strong constraint on the parts to be assembled. This strong constraint requires drive means and control means provided for this purpose.

[0009] Conventional drive systems for machining machine tools are not sized or designed for this implementation. Similarly, control systems have not been considered to manage them. For example, the force axial force to obtain good welding conditions must be controlled throughout the FSW process.

[0010] However, one of the problems resulting from this process lies in the presence of a residual burr on either side of the welded area, a residual burr commonly called "flash". This burr must be removed and the best industrial way to do this is by machining, a process which traditionally controls your positions and not your efforts.

[0011] Means for applying the FSW method exist in the state of the art.

[0012] For example, document W00002704 describes a gantry-based machine with a control system for FSW welding comprising both force and position control. The control mode of the system switches between position control and force control based on control parameters for the force and position of the welding head relative to the workpiece.

[0013] There is also a FSW head such as described in FR3045426 which is designed to be integrated into a machining center to transform you from a machining center to a friction stir welding center.

[0014] None of these methods allow the "flash" burr produced to be machined industrially.

[0015] For example, in the case of a machine tool dedicated to FSW, the part obtained is transferred to another machine tool dedicated to machining,

[0016] In the case where the FSW head is designed to be integrated into a machining center, it is proposed to manually mount a milling tool to be able to machine the burr. However, the limited rotation capacities of the dedicated head and the changeover time do not allow this process to be used effectively for automotive or aeronautical applications which require industrial means to produce at high speed.

[0017] US10016838 describes a friction stir welding tool that can be attached to a spindle of a machine tool. It also describes a machine tool that can accommodate it as well as the technical problem of the temperature management. The proposed solution is a new tool design including a cooling jacket. While the temperature issue is addressed, this document does not describe the problem of force management, particularly the force controls associated with implementing an FSW process on a non-dedicated machine.

[0018] Document JP2020069563 describes a machine tool capable of performing welding machining and cutting machining in a machining area, reducing a cycle time and eliminating heat transfer to a spindle and a bearing supporting the spindle, even when using a multi-purpose tool holder. This document also did not identify the technical problem related to force management and does not provide a solution to it.

[0019] US2011 / 079339 describes a force control equipment for a friction stir welding pin to be mounted on an orbital head that uses a coaxial sensor to measure the downforce. The system includes an added force sensor that measures the downforce which is applied by means of an electric actuator.

[0020] These means are therefore not sufficient on their own to produce parts with friction stir welding in a complete manner and to carry out machining operations in good industrial conditions.

[0021] BRIEF DESCRIPTION OF THE INVENTION

[0022] Having noted this, the applicant carried out research aimed at industrializing this welding process by exploiting its advantages on a large-scale production scale.

[0023] The way to do this is to combine FSW and machining with good performance in a single means, that is, in a single machine tool. The advantages of integrating the FSW process into a machine tool or machining center are numerous, among them:

[0024] - To maintain the significant production capacities of this means (thanks to its performance, its automatic tool changes, etc.),

[0025] - To maintain a machining capacity with good characteristics (in particular the spindle rotation speed), and

[0026] - to integrate an additional manufacturing process, namely F SW.

[0027] The implementation of this combination nevertheless comes up against the antagonism of these two processes on numerous parameters such as axial forces, temperature, rotation speed, feed rate, radial forces, and servocontrols.

[0028] For example, the position controls conventionally implemented in a machining machine tool do not allow for control of the forces required to implement an FSW process.

[0029] The invention is based on a machining machine tool equipped

[0030] of a tool holder spindle preformed with an imprint to accommodate a plurality of tools to be driven in rotation along the axis of the spindle,

[0031] of a part-carrying module(s),

[0032] of a subassembly for guiding and moving the spindle in translation towards the workpiece module and / or from the workpiece module towards the spindle along an axis parallel to the axis of the spindle,

[0033] - a digital control system implementing, in particular, for said guidance and movement sub-assembly, position control, as well as a function for controlling and monitoring the force during movement to a fixed stop.

[0034] According to the invention, the machine tool is remarkable in that it accommodates and rotates a friction stir welding tool comprising a first friction stir welding end with a pin and a shoulder and a second end with a mechanical interface adapted to said spindle imprint, the rotational drive rotating the pin and the shoulder,

[0035] the force required to implement a friction stir welding process being measured and maintained during contact between the tool and the parts to be assembled by the force control and monitoring functionality during movement to a fixed stop to be modified, controlled and maintained with respect to a set value so that a force control is created.

[0036] This machine tool is thus capable of performing friction stir welding (FSW) and machining by switching from one to the other automatically and industrially without operator intervention. This means is industrial and capable of producing parts requiring friction stir welding and machining in large volumes.

[0037] The applicant has succeeded in providing the numerical control managing the axis concerned with the ability to be force-controlled (and no longer position-controlled, at least during the FSW phases) to apply the axial force necessary for friction welding. The different use of a known and available function of the numerical control, namely the so-called "stop approach" function, makes it possible to create force control on said working axis, whereas this function is conventionally used to generate defined forces to block parts or to approach mechanical reference points.

[0038] The new use of such a digital control function for the purpose of implementing an FSW process is therefore particularly original.

[0039] The function of controlling and maintaining the axial force on a working axis of the machining machine tool (the one parallel to the rotation axis of the welding tool) makes it possible to obtain the right force conditions to ensure friction stir welding when the FSW tool is installed.

[0040] Concretely, this function is implemented by giving as a setpoint value of the force (known as the docking force in the context of the stop docking functionality), the desired value for a force necessary for the implementation of an FSW process with rotating shoulder and pin.

[0041] The digital control will thus maintain this force during this process phase, thus creating force control on this axis.

[0042] The machine's design allows for the automatic transition from FSW operations to conventional machining operations, and vice versa, without any manual intervention from the operator, resulting in a significant gain in productivity. This transition is implemented without the addition of hardware or functional modules. (0043] Thus, another object of the invention lies in the working method of such a machining machine tool which proposes machining and the FSW method and, depending on the tool received, to switch from position control to force control and vice versa. The method is described below.

[0044] According to another particularly advantageous characteristic of the invention, said imprint is that corresponding to the HSK standard. The mechanical interface equipping the tool then corresponds to this standard.

[0045] More specifically, according to a preferred but non-limiting embodiment, said imprint is that corresponding to the HSK100 standard and the FSW tool is equipped with an interface of the same standard. This attachment allows more force at the spindle bearings (in comparison with an HSK 63 attachment) and thus allows for greater longevity and a higher feed rate at the FSW process. The advantage of retaining a standard spindle interface is to retain the automatic tool changing, tool magazine and automatic tool loading functions of the machining machine tool. The FSW tool can therefore be stored and made available in the standard magazine of the machine tool.

[0046] Another object of the invention relates to the FSW tool usable by the machine tool of the invention in the method of the invention. Such a tool is described below.

[0047] According to another particularly advantageous characteristic of the invention, said subassembly for guiding and moving the spindle towards the workpiece-holder module and / or the workpiece-holder module towards the spindle along an axis parallel to the axis of the spindle comprises at least one linear motor.

[0048] Such a motorization allows the "stop approach" functionalities in their programming. The linear motor technology makes it possible to read and control with great precision, the force on this axis because the drive is direct. The "stop approach" function of the numerical control of these motors is exploited in an original way by the invention to carry out the welding by using it to control the axis in force (and no longer in position), this maneuver makes it possible to apply a constant axial force, necessary for the FSW process, for the approach phase and during the welding phase of the part. (0049] This motorization also offers the possibility during the welding phase, to use the digital control functions to limit the maximum force and therefore the motor current while working with the position setpoint but limited by the maximum current.

[0050] In Celtic type orientable spindle machining machine tool configurations including:

[0051] a subassembly for guiding and moving the spindle towards the workpiece module and / or the workpiece module towards the spindle along an axis parallel to the axis of the spindle, and

[0052] a digital control implementing in particular for said guidance and movement sub-assembly, a position control as well as a functionality for controlling and monitoring the force during movement to a fixed stop,

[0053] The spindle and the workpiece holder device will be oriented so that the axis of rotation of the spindle is parallel to the axis of translational movement managed by said subassembly.

[0054] Thus, it is not necessary for all movements of the logic structure associated with the spindle to be linear. The orientation of the spindle allows the desired control to be provided on the axis that provides it.

[0055] As explained above, the invention also resides in the working method of a machining machine tool which incorporates all or part of the characteristics described above and which is remarkable in that it comprises the following operations:

[0056] - Friction stir welding operation with force control on the axis parallel to the axis of rotation of the tool, force control created by using for this purpose the functionality of controlling and controlling the force during movement to a fixed stop,

[0057] - Machining operation with position control on the axis parallel to the tool rotation axis.

[0058] More precisely :

[0059] During the FSW operation, there is force control on the axis parallel to the tool rotation axis and position control for the other axes.

[0060] In addition, as explained above, the other axes (those perpendicular to the rotation axis) defining the welding trajectory of the FSW tool can be subject to a force measurement but without force control because they are then themselves position controlled.

[0061] During the machining operation, there is position control for all axes.

[0062] Machining operations can be performed for the purpose of flash burr machining or any other machining.

[0063] It is understood that if the machine tool of the invention can implement such a method, a fleet of at least two machine tools in accordance with the invention can implement a different method where the machines are dedicated to one operation, i.e. one to the FSW operation and the other to machining operations.

[0064] According to another particularly advantageous characteristic of the invention, the method is remarkable in that the friction stir welding operation known as FSW comprises the following steps:

[0065] - installation of an FSW tool with rotating shoulder and pin in the spindle cavity,

[0066] - rotating the FSW tool along its axis of rotation at a speed corresponding to that required for the FSW process,

[0067] - approach by translational movement and with position control on the axis parallel to the rotation axis of the FSW tool until the shoulder of the FSW tool comes into contact with the area to be welded,

[0068] - abandonment of said servo-control in position on the axis parallel to the axis of rotation of the FSW tool,

[0069] - measurement and maintenance of the force with creation of a force control on the axis parallel to the rotation axis of the FSW tool according to an instruction corresponding to that required for the FSW process,

[0070] - moving the FSW tool and / or the parts along one or more axes perpendicular to the axis of rotation of the FSW tool for the purpose of performing the weld,

[0071] - end of welding,

[0072] - abandonment of effort control,

[0073] - withdrawal by translational movement and with position control on the axis parallel to the rotation axis of the FSW tool until the FSW tool is completely separated from the welded area.

[0074] Force monitoring can also be carried out for perpendicular axes, but it is not possible to obtain force control because the correct implementation of the process requires maintaining position control on these axes in order to be able to achieve the desired welding trajectory.

[0075] To implement this force monitoring, according to another particularly advantageous characteristic of the invention, where the machine tool comprises a means of modulating the feed rate on its movement axes, the method comprises an operation of modulating the movement speed along the movement axes not subject to the force control of the method.

[0076] More specifically, according to another characteristic, the method consists, during welding, in modulating the speed of movement of the friction stir welding tool along the axes perpendicular to the rotation axis of the friction stir welding tool to regulate the welding force to a programmed welding force setpoint. This modulation has the effect of regulating the welding force to a programmed welding force setpoint on these axes. This programming ensures a constant force which allows for stable welding conditions and therefore good weld quality (homogeneity, continuity, etc.). This constant force also aims to avoid stalling the electrospindle or exceeding the permissible forces for the subassemblies involved in the movement along these axes. The axes are thus protected and their service life extended.

[0077] Learning is made possible and adaptation to different materials and different thicknesses is also made possible.

[0078] To implement this modulation, in a machine tool comprising a means for measuring the current consumed by the movement subassemblies along the axes perpendicular to the axis of rotation of the friction stir welding tool, the method consists, during welding, in controlling the forces on the movement axes not subject to force control by measuring the current at the current control supplying the movement means so as not to exceed a current corresponding to a force setpoint. We therefore do not control these perpendicular axes directly in force (unlike the stop approach), we keep the control in position to make the desired trajectory, but the speed is then modulated in order to maintain a constant force on this axis during a phase where it is not controlled in force.We speak of synchronous action because the feed speed of these axes is modulated according to the current measurement carried out at the same time.

[0079] This is also a feature available in the management of sub-assemblies of a machining machine tool that is used in the FSW process. Current measurement (which already exists) is used in an original way by creating the control function. Machining machine tools traditionally have several means of modulating the feed rate of the different sub-assemblies. The applicant judiciously exploits this feature to optimize the FSW process.

[0080] This speed modulation can also be used for translational movement along the axis parallel to the tool rotation axis, particularly in the phases preceding the FSW welding phase itself.

[0081] Thus, according to another particularly advantageous characteristic of the invention, the approach operation by translational movement and with position control on the axis parallel to the axis of rotation of the FSW tool until the shoulder of the tool comes into contact with the area to be welded comprises the following operations;

[0082] - control of the feed speed of the axis parallel to the rotation axis of the FSW tool until the tool pin comes into contact with the area to be welded, then

[0083] - modulation of the feed speed of the axis parallel to the rotation axis of the FSW tool to regulate the fusion force to a programmed fusion force setpoint until contact of the tool shoulder with the area to be welded.

[0084] The control is carried out according to a programmed speed while the speed modulation is a speed regulation taking into account the measured value of the current by a synchronized action of current measurement.

[0085] Such a process allows for rapid advancement adapted to the material and its thickness to optimize the duration of the approach movements.

[0086] The applicant further noted that the management of the temperature of the contact zone or those of the constituent elements subjected to additional constraints constituted one of the technical problems to be resolved due to the antagonism of this management depending on the process implemented. Indeed, the temperature rise is sought and necessary at the level of the tool / part contact zone for an FSW operation whereas it is to be avoided for a machining operation and this for at least two reasons: the machining quality and the service life of the components of the machine tool (in particular the spindle).

[0087] According to a particularly advantageous characteristic of the invention, said friction stir welding tool making it possible to implement the friction stir welding operations described above and comprising a first friction stir welding end with a pin and a shoulder and a second end with a mechanical interface, comprises a thermal insulator between the first end and the interface. Such a characteristic allows a faster temperature rise of the end of the tool and prevents the temperature from rising too quickly at the pin to protect its guide means.

[0088] More specifically, according to another particularly advantageous characteristic of the invention, said tool is preformed with a plurality of separate heat diffusion discs arranged between the first end and the interface.

[0089] According to another particularly advantageous characteristic of the invention, thermal insulation inserts are inserted between said discs.

[0090] These first characteristics constitute solutions for thermal insulation implemented at the FSW tool level.

[0091] In addition to the tool, the invention makes it possible to distribute the functionalities of the friction stir welding process in two parts of the machining machine tool:

[0092] The subassembly for guiding and driving in translation along an axis parallel to the axis of rotation of the tool and the electro-spindle.

[0093] The machine tool spindle must have the characteristics necessary for FSW, particularly with regard to the absorption of axial and radial forces, while retaining its machining capabilities.

[0094] We then understand that it is possible to implement an FSW process in existing machining machine tools by:

[0095] — equipping it with an FSW tool,

[0096] - changing the programming of the numerical control managing the guidance and movement sub-assembly on an axis parallel to the rotation axis of said tool to create force control,

[0097] - changing the electro-spindle (which is a sub-assembly that is changed regularly) for an electro-spindle capable of taking up the forces.

[0098] The fundamental concepts of the invention having just been set out above in their most elementary form, other details and characteristics will emerge more clearly on reading the description which follows and with reference to the appended drawings, giving by way of non-limiting examples, embodiments of a machine tool and / or its functional subassemblies in accordance with the invention.

[0099] BRIEF DESCRIPTION OF THE DRAWINGS

[0100] [Fig. 1] is a schematic drawing of a partial perspective view from above illustrating a first embodiment of a machine tool according to the invention;

[0101] [Fig. 2] is a schematic drawing of a partial perspective view from above illustrating another embodiment of a first machine tool according to the invention;

[0102] [Fig. 3] is a schematic drawing of an exterior side view of an embodiment of an assembly formed by an electro-spindle and a tool in accordance with the invention:

[0103] [Fig. 4] is a schematic drawing of an exterior view of an embodiment of a tool holder according to the invention;

[0104] [Fig. 5] is a diagram illustrating an embodiment of management of the servo-controls on the axis parallel to the axis of rotation of the tool according to the cycle times of an FSW process in accordance with the invention;

[0105] [Fig. 6] is a schematic drawing of a partial side view in section illustrating the positions taken by the FSW tool relative to two parts to be joined;

[0106] [Fig. 7] is a schematic drawing of a partial front view illustrating the positions taken by the FSW tool relative to two parts to be joined;

[0107] [Fig. 8] is a schematic drawing of a partial side view in section illustrating one of the positions taken by the FSW tool relative to the two parts to be joined;

[0108] [Fig. 9] is a diagram illustrating an embodiment of speed management on the axes perpendicular to the axis of rotation of the tool according to the cycle times of an FSW process according to the invention;

[0109] [Fig. 10] is a diagram illustrating an embodiment of managing the translation speeds on the axis parallel to the axis of rotation of the tool according to the cycle times of an FSW process according to the invention.

[0110] DESCRIPTION OF PREFERRED EMBODIMENTS

[0111] As illustrated in Figure 1, the machine tool referenced M as a whole is equipped with: - an electro-tool-holder spindle 100 preformed with an imprint to accommodate a plurality of tools to be driven in rotation along the axis of the spindle which is here parallel to the horizontal Z axis, - a workpiece holder module 200, - a subassembly 210 for guiding and moving in translation parallel to the Z axis of the workpiece holder module 200 towards the spindle 100 along an axis parallel to the axis of the spindle, a tool storage module 300, - a 400 tool exchange module.

[0112] The electro-spindle 100 is arranged in a sleeve which is guided and set in translational movement along a vertical plane defined by the X and Y axes facing the workpiece-carrying module 200 which is movable in translation perpendicular to said plane. According to a preferred embodiment, the workpiece-carrying module is set in translational movement by means of linear motors.

[0113] The machine tool M comprises a numerical control C implementing in particular for said guiding and movement subassembly 210, a position control as well as a functionality for controlling and monitoring the force during a movement to a fixed stop (stop approach function).

[0114] Figure 3 illustrates the electro-spindle 100 receiving an embodiment of an FSW 500 tool according to the invention.

[0115] The electro-spindle 100 is sized to be able to withstand the significant forces used during the FSW operation. It accommodates and rotates the tool 500 parallel to the Z axis. By its rear end 110, it connects to electrical power supply, control and possibly hydraulic power supply modules. (0116] The 500 friction stir welding tool consists of two parts:

[0117] - a first part forming the first end 510 with a pin 511 and a shoulder 512, and

[0118] ~ a second part or tool holder 520 forming the second end with a mechanical interface 521 adapted to said imprint of the electro-branch. These two parts can be separated in order to ensure maintenance of the tool and change the end 510 likely to wear out.

[0119] According to the embodiment illustrated by this figure, said friction stir welding tool 500 comprises a thermal insulator 530 between the first end 510 and the interface 521. More precisely, the thermal insulator 530 is constituted by a plurality of discs 531 spaced apart for the purpose of diffusing the heat produced and therefore of separation between the electro-branch and the welding zone.

[0120] As illustrated more precisely in Figure 4, the tool holder 520 which is formed by the friction stir welding tool 500 from which the first end 510 has been removed, comprises a central hub screwed to the interface 521 and preformed:

[0121] - in the internal axial part, an axial recess 540 to accommodate the first end 510 of the tool 500 formed by the shoulder and the pin (not illustrated),

[0122] - in the external peripheral part, radial projections forming spaced discs 531 and between which thermal insulating inserts 532 are inserted. For the purposes of fixing by screws, the insulating inserts 532 are crossed by bores aligning with bores made in the discs 531. This assembly forms the thermal insulator 530 between the first end 510 of the tool 500 and the interface 521.

[0123] As illustrated, said tool 500 is equipped with a mechanical interface 521 corresponding to the HSK100 standard which allows it to be managed like a conventional tool by the tool storage module 300 and by the tool exchange module 400.

[0124] The insulating inserts are chosen from aluminosilicate or sintered ceramic type materials known for their insulating capabilities.

[0125] Thus, according to a preferred but non-limiting embodiment, the material of the insulating inserts is selected from the following list:

[0126] - thermal insulation comprising 90% mica and 10% resin,

[0127] - thermal insulation comprising 55% fluorophoretic and 45% borosilicate. [012S] The other functions of the numerically controlled machining machine tool, such as the mechanism for loading tools into the machine, the automatic tool changing mechanism, the tool magazine, the closed machining area, the air treatment of this area, etc., complete this machine M and make it an industrial means of manufacturing parts requiring FSW and machining.

[0129] The machine tool M' illustrated in Figure 2 is also capable of integrating an FSW functionality in accordance with the invention. Although the electro-spindle 100' is positioned and set in motion at the end of an articulated arm-type structure, the latter is secured to a carriage moving in translation along the X axis. To implement the invention, said articulated structure will orient the electro-spindle 100' as illustrated, that is to say in such a way that the axis of rotation of the electro-spindle 100' and therefore of the FSW tool that it carries during the FSW process is parallel to the X axis.

[0130] According to a preferred embodiment, the movement of said carriage is carried out by linear motors.

[0131] Figures 5 to 7 illustrate the implementation of the method of the invention on the circular parts PI and P2 which must be welded together according to a circular weld bead following the external peripheral edge of the part P.

[0132] The diagram in Figure 5 illustrates the cycle times of the steps or phases numbered from 1 to 7 constituting the actual FSW operation. Machining may have taken place previously and must take place after for the machining of the so-called flash burr.

[0133] The tool 500' has a first end 510' formed of a pin 51 T and a rotating shoulder 512'. It is installed in an electro-spindle not shown in these figures.

[0134] The FSW 500' tool is rotated at a speed corresponding to that required for the FSW process.

[0135] From 1 to 2, the logical structure associated with the electro-spindle or that associated with parts P1 and P2 ensures the bringing together of the tool and the parts by translational movement and with position control on the axis parallel to the axis of rotation of the FSW 500' tool until the shoulder 512' of the tool 500' comes into contact with the area to be welded S.

[0136] In step 3, the 51 T' pin has penetrated the material. In steps 1 and 7, the tool is moved away from the parts.

[0137] From step 2, the position control on this translation is abandoned and replaced by the measurement and maintenance of the force with force control according to a setpoint corresponding to that required for the FSW method. In accordance with the invention, this is made possible thanks to the functionality of controlling and monitoring the force during a movement to a fixed stop to which a setpoint corresponding to that of an FSW force and not that corresponding to a clamping constraint or to contact with a stop has been fixed.

[0138] Steps 4, 5 and 6 see the movement of the tool 500' and / or the parts P1 and P2 to be welded along one or more axes perpendicular to the axis of rotation of the FSW tool 500' for the purpose of producing a circular trajectory of the weld S.

[0139] Step 6 defines the end of the weld, the circular path having passed the tool 500' over the start of the weld bead.

[0140] The force control is abandoned at point 6. A withdrawal movement, by translational movement with position control on the axis parallel to the rotation axis of the FSW tool until the FSW tool 500' is completely separated from the welded zone S, ends the process at step 7.

[0141] The FSW 500' tool can then be replaced with a machining tool to machine the burr created.

[0142] Then, as for the other functions to be provided for the FSW, in particular the absorption of radial forces, the rotation speed of the tool or the control of the temperature will be managed by the Spindle organ (the radial forces will also be absorbed by the working axes of the machine used).

[0143] The diagrams in Figures 9 and 10 illustrate the speed management during the process.

[0144] Figure 9 shows the speed management on the axes perpendicular to the axis of rotation of the tool according to the cycle times of an FSW process according to the invention where:

[0145] - during phases 1 to 2, the feed speed of the axes perpendicular to the tool rotation axis is controlled by the numerical control according to a programmed trajectory and feed speed;

[0146] -during phases 3 to 6, the programmed feed speed of the axes perpendicular to the tool rotation axis is modulated to regulate the welding force according to a programmed welding force setpoint;

[0147] - during phases 6 to 7, the feed speed of the axes perpendicular to the tool rotation axis is again controlled by the numerical control according to a programmed trajectory and feed speed.

[0148] Figure 10 shows the management of translation speeds on the axis parallel to the tool rotation axis according to the cycle times of an FSW process where:

[0149] - during phases 1 to 2, the feed speed along the axis parallel to the rotation axis of the FSW tool is controlled by the numerical control until the tool pin comes into contact with the area to be welded according to a programmed trajectory and speed, [0150J- during phases 2 to 3, the feed rate along the axis parallel to the rotation axis of the FSW tool is modulated to regulate the fusion force to a programmed fusion force setpoint until contact of the shoulder of the tool with the area to be welded,

[0151] - during phases 3 to 7, given that the welding trajectory is located in a plane perpendicular to the axis of rotation of the tool, the speed of movement along the axis parallel to the axis of rotation of the FSW tool is controlled by the numerical control until the end of the weld and even during the tool withdrawal movement.

[0152] It is understood that the device which has just been described and represented above has been done so with a view to disclosure rather than limitation. Of course, various arrangements, modifications and improvements may be made to the above examples, without departing from the scope of the invention.

Claims

Claims

1. Machining machine tool (M) equipped - a tool holder spindle (100) preformed with an imprint to accommodate a plurality of tools to be driven in rotation along the axis of the spindle, - a part-carrying module(s) (200), ~ of a subassembly (210) for guiding and moving in translation the spindle towards the workpiece-holder module and / or the workpiece-holder module towards the spindle along an axis parallel to the axis of the spindle (100), - a digital control (C) implementing in particular for said subassembly (210) for guidance and movement, a position control as well as a functionality for controlling and monitoring the force during movement to a fixed stop, CHARACTERIZED BY THE FACT THAT it accommodates and rotates a friction stir welding tool (500) comprising a first friction stir welding end (510) with a pin (511) and a shoulder (512) and a second end (520) with a mechanical interface (521) adapted to said imprint of the pin (100), the rotational drive rotating the pin (511) and the shoulder (512), the force necessary for implementing a friction stir welding process being measured and maintained for the purpose of creating a force control during contact between the tool (500) and the parts to be assembled by the functionality of controlling and monitoring the force during movement to a fixed stop.

2. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT said subassembly (210) for guiding and moving in translation the spindle (100) towards the workpiece-holder module (200) and / or the workpiece-holder module (200) towards the spindle (100) along an axis parallel to the axis of the spindle (100) comprises at least one linear motor.

3. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT said imprint is that corresponding to the HSK100 standard.

4. Working method of a machining machine tool (M) according to any one of claims 1 to 3, CHARACTERIZED IN THAT it comprises the following operations: - Friction stir welding operation with force control on the axis parallel to the axis of rotation of the tool (500), force control created by using for this purpose the functionality of controlling and monitoring the force during movement to a fixed stop, -Machining operation with position control on a tax parallel to the tool rotation axis (500),

5. Working method of a machining machine tool (M) according to any one of claims 1 to 3, CHARACTERIZED IN THAT the friction stir welding operation comprises the following steps: - installation of a friction stir welding tool (500') with shoulder (512') and pin (51 T) rotating in the spindle cavity (100'), - rotating the friction stir welding tool (500') along its axis of rotation at a speed corresponding to that required for the friction stir welding process, - approach by translational movement and with position control on the axis parallel to the axis of rotation of the friction stir welding tool (500') until the shoulder (512') of the friction stir welding tool (50Q') comes into contact with the area to be welded, - abandonment of said servo-control in position on Tax parallel to the axis of rotation of the friction stir welding tool (500'), - measurement and maintenance of the force with creation of a force control on the axis parallel to the axis of rotation of the friction stir welding tool (500') according to an instruction corresponding to that required for the friction stir welding process, - moving the friction stir welding tool (500') and / or the area to be welded along one or more axes perpendicular to the rotation axis of the friction stir welding tool (500') for the purpose of performing the weld, - end of welding, - abandonment of effort control, ~ withdrawal by translational movement and with position control on the axis parallel to the rotation axis of the friction stir welding tool (500') until the friction stir welding tool (500') is completely separated from the welded area.

6. Working method according to claim 5 where the machine tool comprises a means for modulating the feed rate on its movement axes, CHARACTERIZED IN THAT it comprises an operation for modulating the movement speed along the movement axes not subject to force control.

7. Working method according to claim 6, CHARACTERIZED IN THAT it consists, during welding, in modulating the speed of movement of the friction stir welding tool (500') along the axes perpendicular to the axis of rotation of the friction stir welding tool (500') to regulate the welding force to a programmed welding force setpoint.

8. Working method according to claim 6 where the machine tool comprises a means for measuring the current consumed by the movement sub-assemblies along the axes perpendicular to the axis of rotation of the friction stir welding tool (500'), CHARACTERIZED IN THAT it consists, during welding, in controlling the forces on the movement axes not subject to force control by measuring the current at the current control supplying the movement means so as not to exceed a current corresponding to a force setpoint.

9. Working method according to claim 5 or 6, CHARACTERIZED IN THAT it comprises an operation of controlling the speed of movement of the friction stir welding tool (500') along the axis parallel to the axis of rotation of the friction stir welding tool (500') outside of the performance of the weld.

10. Working method according to any one of claims 5 to 8, CHARACTERIZED IN THAT the approach operation by translational movement and with position control on the axis parallel to the axis of rotation of the friction stir welding tool (500') until the shoulder (512) of the friction stir welding tool (500*) comes into contact with the area to be welded includes the following operations: - control of the feed speed of the axis parallel to the rotation axis of the friction stir welding tool (500') until the contact of the pin (51 T) of the friction stir welding tool (500') with the area to be welded, then - modulation of the feed speed of the axis parallel to the rotation axis of the friction stir welding tool (500') to regulate the fusion force to a programmed fusion force setpoint until contact of the shoulder (512') of the friction stir welding tool (500') with the area to be welded. [Claim 11J Friction stir welding tool (500) for carrying out the friction stir welding operations of the method according to any one of claims 4 to 10 carried out by the machine tool according to any one of claims 1 to 3 and comprising a first friction stir welding end (510) with a pin (511) and a shoulder (512) and a second end (520) with a mechanical interface (521), CHARACTERIZED BY THE FACT THAT it comprises a thermal insulator (530) between the first end (510) and the interface (521).

12. Tool (500) according to claim 11, CHARACTERIZED BY THE FACT THAT it is preformed with a plurality of separate heat diffusion discs (531) arranged between the first end (510) and the interface (521).

13. Tool (500) according to claim 12, CHARACTERIZED BY THE FACT THAT thermal insulation inserts (532) are inserted between said discs (531).

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