Machining machine tool employing a friction stir welding process, its working process and friction stir welding tool

Abstract

Machining machine tool implementing a friction stir welding process, its working method and friction stir welding tool. The invention relates to a machining machine tool which is remarkable in that it houses and drives in rotation a friction stir welding tool (500) comprising a first friction stir welding end (510) with a rotating pin (511) and shoulder (512), the force required to implement a friction stir welding process being measured and maintained for the purpose of creating force control during the contact between the tool (500) and the parts to be joined by the force control functionality during movement to a fixed stop. The invention also relates to the working method and the tool for implementing the friction stir welding operations. Figure for the abstract: Fig. 1

Description

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

[0001] SCOPE 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 PRIOR ART

[0004] The friction stir welding process, known by the abbreviation FSW for "Friction Stir Welding", is a welding process which consists of joining two parts by bringing their contact surfaces to a paste-like state by means of a rotating tool specially designed for this purpose.

[0005] This tool conventionally comprises a shoulder and a coaxial pin which, when applied and rotated, locally bring the parts to be joined into a molten state. The tool is applied and rotates along the contact line between the two parts to be joined, or alternatively, by passing through the first layer to weld it to the second for two overlapping parts.

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

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

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

[0009] Conventional drive systems for machining tools are not designed or intended for this application. Similarly, control systems have not been designed to manage these processes. Thus, for example, the axial force required to achieve the correct 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 both sides of the welded piece, a residual burr commonly called a "flash". This burr must be removed, and the best industrial way to do this is by machining, a process which classically controls positions but not forces.

[0011] Means for applying the FSW process exist in the state of the technical.

[0012] For example, document WO0002704 describes a gantry-style machine with a control system for FSW welding comprising both force and position control. The system's control mode 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 an FSW head such as that described in FR3045426 which is designed to be integrated into a machining center to transform it from a machining center to a friction stir welding center.

[0014] None of these means allows 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 cases where the FSW head is designed to be integrated into a machining center, it is proposed to manually mount a milling tool to machine the burr. However, the limited rotational capabilities of the dedicated head and the changeover time prevent the efficient use of this method for automotive or aerospace applications, which require industrial equipment for high-volume production.

[0017] These means are therefore not sufficient on their own to produce parts with friction stir welding in a complete manner.

[0018] BRIEF DESCRIPTION OF THE INVENTION

[0019] Noting this, the applicant conducted research aimed at industrializing this welding process by exploiting its advantages on a large production scale.

[0020] The way to do this is to combine FSW and machining with good performance in a single means, i.e., in a single machine tool. The advantages of integrating the FSW process into a machine tool or machining center are numerous, including:

[0021] - To maintain the significant production capacities of this means (thanks to its per forms, its automatic tool changes, etc...),

[0022] - To maintain a machining capacity with good characteristics (in particular the spindle rotation speed), and

[0023] - to integrate an additional manufacturing process, namely FSW.

[0024] The implementation of this combination nevertheless encounters the antagonism of these two processes on many parameters such as axial forces, temperature, rotation speed, feed speed, radial forces, servo systems.

[0025] For example, the position control systems conventionally implemented in a machining machine tool do not allow for the control of the forces required to the implementation of an FSW process.

[0026] The invention is based on a machining machine tool equipped

[0027] of a pre-formed tool holder spindle with a cavity to accommodate a plurality of tools to be driven in rotation about the axis of the spindle,

[0028] of a part-carrying module,

[0029] of a sub-assembly for guiding and moving in translation from the spindle to the workpiece holder module and / or from the workpiece holder module to the spindle along an axis parallel to the axis of the spindle,

[0030] - of a numerical control system implementing in particular for said sub-assembly guidance and movement control, position control, as well as a function for controlling and managing force during movement up to a fixed stop.

[0031] According to the invention, the machine tool is remarkable in that it accommodates and drives in rotation 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 footprint, the rotation drive driving in rotation the pin and the shoulder,

[0032] the force required to implement a friction stir welding process being measured and maintained during the contact between the tool and the parts to be joined by the force control functionality during a movement up to a fixed stop to be modified, controlled and maintained with respect to a setpoint value so that a force control is created.

[0033] This machine tool is thus capable of performing friction stir welding (FSW) and machining, switching between the two automatically and industrially without operator intervention. This means is industrial and capable of producing large volumes of parts requiring friction stir welding and machining.

[0034] The applicant has succeeded in giving the numerical control managing the axis in question the ability to be force-controlled (rather than position-controlled, at least during the FSW phases) in order 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 positioning" function, makes it possible to create force control on the said working axis, whereas this function is conventionally used to generate defined forces to clamp parts or to position mechanical reference points.

[0035] The novel use of such a numerical control function for the purpose of implementing an FSW process is therefore particularly original.

[0036] The function of controlling and maintaining the axial force on a working axis of the The machining machine tool (the one parallel to the axis of rotation of the welding tool) makes it possible to obtain the correct force conditions to ensure friction stir welding when the FSW tool is installed.

[0037] In concrete terms, this function is implemented by giving as the setpoint value of the effort (known as the docking force within the framework of the stop docking functionality), the desired value for an effort required to implement an FSW process with rotating shoulder and pin.

[0038] The numerical control will thus maintain this effort during this phase of the process, thereby creating a force control on this axis.

[0039] The machine design thus allows switching from FSW operation to conventional machining operations, and vice versa, automatically without any manual intervention by the operator, hence the significant gain in productivity.

[0040] Thus, another object of the invention lies in the working method of such a machining machine tool which offers machining and the FSW process and, depending on the tool used, the ability to switch from position control to force control and vice versa. The method is described below.

[0041] According to another particularly advantageous feature of the invention, said footprint is that corresponding to the HSK standard. The mechanical interface equipping the tool then corresponds to this standard.

[0042] More specifically, according to a preferred but non-limiting embodiment, said tool footprint is that corresponding to the HSK100 standard, and the FSW tool is equipped with an interface of the same standard. This attachment allows for greater load on the spindle bearings (compared to an HSK 63 attachment) and thus enables greater tool life and a higher feed rate in the FSW process. The advantage of retaining a standard spindle interface is that the automatic tool changer, tool magazine, and automatic tool loading functions of the machining machine tool are maintained. The FSW tool can therefore be stored and made available in the machine tool's standard magazine.

[0043] Another object of the invention relates to the FSW tool usable by the machine tool of the invention in the process of the invention. Such a tool is described below.

[0044] According to another particularly advantageous feature of the invention, said subassembly for guiding and moving in translation of the spindle towards the workpiece holder module and / or of the workpiece holder module towards the spindle along an axis parallel to the axis of the spindle comprises at least one linear motor.

[0045] Such a motorization allows for "stop-to-stop" functionality in its programming. Linear motor technology makes it possible to read and control the force on this axis with high precision because the drive is direct. The "stop-to-stop" function of the numerical control of these motors is used from original way by the invention to perform 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 docking phase and during the welding phase of the part.

[0046] This motorization also offers the possibility during the welding phase of using the numerical control functions to limit the maximum effort and therefore the motor current while working with the position setpoint but limited by the maximum current.

[0047] In machine tool configurations with a swiveling spindle of the type comprising:

[0048] a sub-assembly for guiding and moving the spindle in translation towards the workpiece holder module and / or from the workpiece holder module towards the spindle along an axis parallel to the spindle axis, and

[0049] a numerical control system implementing, in particular for said guiding and movement sub-assembly, a position control system as well as a function for controlling and managing the force during movement up to a fixed stop,

[0050] The spindle and the workpiece holder will be oriented so that the axis of rotation of the spindle is parallel to the axis of translational movement controlled by said sub-assembly.

[0051] Thus, it is not necessary for all the movements of the logic structure associated with the spindle to be linear. The orientation of the spindle allows the desired control to be applied to the axis that provides it.

[0052] As explained above, the invention also lies 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:

[0053] - Friction stir welding operation with force control on the axis parallel to the axis of rotation of the tool, force control created by exploiting for this purpose the functionality of controlling and managing the force during movement up to a fixed stop,

[0054] - Machining operation with position control on the axis parallel to the axis of tool rotation.

[0055] More specifically:

[0056] During the FSW operation, there is force control on the axis parallel to the axis of rotation of the tool and position control for the other axes.

[0057] Furthermore, as explained above, the other axes (those perpendicular to the axis of rotation) defining the welding path of the FSW tool can be subjected to force measurement, but without force control, since they are then themselves position-controlled.

[0058] During the machining operation, there is position control for all axes.

[0059] Machining operations can be carried out for the purpose of "flash" burr machining or any other machining.

[0060] It is understood that if the machine tool of the invention can implement such a process, a fleet of at least two machine tools conforming to the invention can implement a different process where the machines are dedicated to one operation, i.e. one to the FSW operation and the other to the machining operations.

[0061] According to another particularly advantageous feature of the invention, the process is remarkable in that the friction stir welding (FSW) operation comprises the following steps:

[0062] - Installation of an FSW tool with rotating shoulder and pin in the footprint from the spit,

[0063] - rotation of the FSW tool about its axis of rotation at a corresponding speed equivalent to that required for the FSW process,

[0064] - approach 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 FSW tool makes contact with the area to be welded,

[0065] - abandonment of said position control on the axis parallel to the axis of rotation of the FSW tool,

[0066] - measurement and maintenance of force with creation of a force control on the axis parallel to the axis of rotation of the FSW tool according to a setting corresponding to that required for the FSW process,

[0067] - setting in motion the FSW tool and / or the parts along one or more axes per pendulum-shaped to the axis of rotation of the FSW tool for the purpose of welding,

[0068] - end of the weld,

[0069] - abandonment of the effort control,

[0070] - retraction by translational movement and with position control on the axis parallel to the axis of rotation of the FSW tool until the FSW tool is completely removed from the welded area.

[0071] Force monitoring can also be carried out for perpendicular axes but it is not possible to obtain force control because the proper implementation of the process requires maintaining position control on these axes in order to be able to make the desired welding trajectory.

[0072] To implement this force monitoring, according to another particularly advantageous feature of the invention, where the machine tool includes a means of modulating the feed rate on its axes of movement, the method includes an operation of modulating the speed of movement along the axes of movement the process is not subject to force control.

[0073] More specifically, according to another feature, the process consists, during welding, of modulating the speed of movement of the friction stir welding tool along axes perpendicular to the axis of rotation of the friction stir welding tool in order 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 prevent the electrospindle from stalling or exceeding the permissible forces for the sub-assemblies involved in the movement along these axes. The axes are thus protected and their service life extended.

[0074] Learning is made possible and adaptation to different materials and different thicknesses is also made possible.

[0075] To implement this modulation, in a machine tool comprising a means for measuring the current consumed by the sub-assemblies that drive the movement along axes perpendicular to the axis of rotation of the friction stir welding tool, the method consists, during welding, of controlling the forces on the axes of movement not subject to force control by measuring the current at the current control point supplying the drive means in order to avoid exceeding a current corresponding to a force setpoint. Therefore, force control is not applied directly to these perpendicular axes (unlike stop positioning); position control is maintained to follow the desired trajectory, but the speed is then modulated to maintain a constant force on this axis during a phase when it is not subject to force control.This is referred to as synchronous action because the advance speed of these axes is modulated according to the current measurement performed simultaneously.

[0076] This is also a feature available in the management of sub-assemblies of a machining machine tool, which 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 typically have several means of modulating the feed rate of the different sub-assemblies. The applicant judiciously exploits this feature to optimize the FSW process.

[0077] This speed modulation can also be used for translational movement along the axis parallel to the axis of rotation of the tool, particularly in the phases preceding the FSW welding phase itself.

[0078] Thus, according to another particularly advantageous feature of the invention, the approach operation by translational movement and with servo control in Positioning on the axis parallel to the axis of rotation of the FSW tool until the tool shoulder makes contact with the area to be welded includes the following operations:

[0079] - control of the feed rate of the axis parallel to the axis of rotation of the FSW tool until the tool's pin makes contact with the area to be welded, then

[0080] - modulation of the feed rate of the axis parallel to the axis of rotation of the tool FSW to regulate the fusion force to a programmed fusion force setpoint until the tool shoulder contacts the area to be welded.

[0081] The control is carried out according to a programmed speed while the speed modulation is a regulation of the speed taking into account the measured value of the current by a synchronized action of measuring the current.

[0082] Such a process makes it possible to achieve a rapid advance adapted to the material and its thickness in order to optimize the duration of the approach movements.

[0083] The applicant further noted that managing the temperature of the contact zone or of the constituent elements subjected to additional stresses constituted one of the technical problems to be solved due to the conflicting nature of this management depending on the process implemented. Indeed, a temperature increase is desired and necessary at the tool / workpiece contact zone for a FSW operation, whereas it must be avoided for a machining operation, for at least two reasons: machining quality and the lifespan of the machine tool components (particularly the spindle).

[0084] According to a particularly advantageous feature of the invention, said friction stir welding tool, which performs the friction stir welding operations described above and comprises a first friction stir welding end with a pin and a shoulder and a second end with a mechanical interface, includes thermal insulation between the first end and the interface. This feature allows for a faster temperature rise at the tool end and prevents the spindle from overheating too quickly to protect its guiding means.

[0085] More specifically, according to another particularly advantageous feature of the invention, said tool is pre-formed from a plurality of separate heat diffusion discs arranged between the first end and the interface.

[0086] According to another particularly advantageous feature of the invention, thermal insulation inserts are interposed between said discs.

[0087] These initial characteristics constitute solutions for thermal insulation implemented at the level of the FSW tool.

[0088] In addition to the tool, the invention makes it possible to distribute the functionalities of the friction stir welding process in two components of the machining machine tool:

[0089] The subassembly for guiding and driving in translation along a parallel axis to the axis of rotation of the tool and the electro-spindle.

[0090] The spindle of the machine tool must have the characteristics necessary for FSW with regard in particular to the absorption of axial and radial forces, while retaining its machining capabilities.

[0091] It is then understood that it is possible to implement an FSW process in existing machining machine tools by:

[0092] - equipping it with an FSW tool,

[0093] - changing the programming of the numerical control managing the sub-assembly guiding and setting in motion on an axis parallel to the axis of rotation of said tool to create a force control system,

[0094] - changing the electro-spindle (which is a sub-assembly that is changed regularly) for an electro-spindle capable of absorbing the stresses.

[0095] The fundamental concepts of the invention having been set out above in their most elementary form, other details and characteristics will become clearer from the reading of the following description and with regard to the attached drawings, giving by way of non-limiting examples, embodiments of a machine tool and / or its functional sub-assemblies in accordance with the invention. Brief description of the drawings

[0096] [Fig. 1] is a schematic drawing of a partial perspective top view illustrating a first embodiment of a machine tool according to the invention;

[0097] [Fig.2] is a schematic drawing of a partial perspective top view illustrating another embodiment of a first machine tool according to the invention;

[0098] [Fig.3] is a schematic drawing of an external side view of an embodiment of an assembly formed by an electro-spindle and a tool according to the invention;

[0099] [Fig.4] is a schematic drawing of an external view of an embodiment of a tool holder according to the invention;

[0100] [Fig.5] is a diagram illustrating an embodiment of servo control management 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;

[0101] [Fig.6] is a schematic drawing of a partial side view in section illustrating the positions taken by the FSW tool in relation to two parts to be assembled;

[0102] [Fig.7] is a schematic drawing of a partial front view illustrating the positions taken by the FSW tool in relation to two parts to be assembled;

[0103] [Fig.8] is a schematic drawing of a partial side view in section illustrating one of the positions taken by the FSW tool with respect to the two parts to be assembled;

[0104] [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;

[0105] [Fig. 10] is a diagram illustrating an embodiment of managing 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.

[0106] DESCRIPTION OF PREFERRED IMPROVEMENT MODES

[0107] As illustrated in [Fig. 1], the machine tool referenced M as a whole is equipped: - a pre-formed electro-spindle tool holder 100 with a cavity to accommodate a plurality of tools to be driven in rotation around the spindle axis, which is parallel to the horizontal Z-axis, - a workpiece holder module 200, - of a sub-assembly 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 300 tool storage module, - a 400 tool exchange module.

[0108] The electro-spindle 100 is arranged in a sleeve which is guided and moved in translation along a vertical plane defined by the X and Y axes opposite the workpiece-holding module 200, which is movable in translation perpendicular to said plane. According to a preferred embodiment, the workpiece-holding module is moved in translation by means of linear motors.

[0109] The machine tool M includes a numerical control C implementing in particular for said guiding and moving sub-assembly 210, a position control as well as a function for controlling and managing the force during a movement up to a fixed stop (stop docking function).

[0110] Fig. 3 illustrates the electro-spindle 100 housing an embodiment of an FSW 500 tool according to the invention.

[0111] The electro-spindle 100 is dimensioned to be able to withstand the significant forces exerted during the FSW operation. It houses and drives the tool 500 in rotation parallel to the Z-axis. Its rear end 110 connects to electrical power, control, and optionally hydraulic power supply modules.

[0112] The 500 friction kneading welding tool comprises two parts:

[0113] - a first part forming the first end 510 with a pawl 511 and a shoulder 512, and

[0114] - a second part or tool holder 520 forming the second end with a mechanical interface 521 adapted to said electro-spindle footprint. These two parts can be separated to ensure tool maintenance and to change the end 510 which is subject to wear.

[0115] According to the embodiment illustrated by this figure, said friction stir welding tool 500 includes a thermal insulator 530 between the first end 510 and the interface 521. More specifically, the thermal insulator 530 consists of a plurality of discs 531 spaced apart for the purpose of diffusing the heat produced and thus separating the electro-spindle from the welding area.

[0116] As illustrated more precisely in [Fig.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 fixed by screwing to the interface 521 and preformed:

[0117] - in the internal axial part, with an axial recess 540 to accommodate the first end 510 of tool 500 formed by the shoulder and the pin (not shown),

[0118] - in an outer peripheral part, of radial projections forming discs 531 spaced apart and between which thermal insulation inserts 532 are inserted. For the purpose of fixing by screws, the insulating inserts 532 are traversed by bores which align with bores made in the discs 531. This assembly forms the thermal insulation 530 between the first end 510 of the tool 500 and the interface 521.

[0119] 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.

[0120] The insulating inserts are chosen from aluminosilicate or sintered ceramic type materials known for their insulating capabilities.

[0121] Thus, according to a preferred but non-limiting embodiment, the material for the insulating inserts is selected from the following list:

[0122] - thermal insulation comprising 90% mica and 10% resin,

[0123] - thermal insulation comprising 55% fluorophlogopite and 45% borosilicate.

[0124] The other functions of the CNC machining machine tool, such as the tool loading mechanism in the machine, the automatic tool changing mechanism, the tool magazine, the enclosed 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.

[0125] The machine tool M' illustrated in [Fig. 2] is also capable of integrating an FSW functionality according to 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 fixed 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, so that the axis of rotation of the electro-spindle 100' and therefore the FSW tool that it carries during the FSW process is parallel to the X axis.

[0126] According to a preferred embodiment, the movement of said carriage is achieved by linear motors.

[0127] Figures 5 to 7 illustrate the implementation of the method of the invention on the circular parts PI and P2 which are to be welded together according to a circular weld bead following the outer peripheral edge of part P.

[0128] The diagram in [Fig. 5] illustrates the cycle times of the steps or phases numbered 1 to 7 constituting the FSW operation itself. Machining may have taken place previously and must take place afterward for the machining of the so-called flash burr.

[0129] The tool 500' has a first end 510' formed of a rotating pin 511' and shoulder 512'. It is installed in an electro-spindle not shown in these figures.

[0130] The FSW 500' tool is driven in rotation at a speed corresponding to that required for the FSW process.

[0131] From 1 to 2, the logic structure associated with the electro-spindle or that associated with parts PI and P2 ensures the approach of the tool and the parts by translational movement and with position control on the axis parallel to the axis of rotation of the tool FSW 500' until the shoulder 512' of the tool 500' is in contact with the area to be welded S.

[0132] In step 3, the pin 511' penetrated the material. In steps 1 and 7, the tool is moved away from the parts.

[0133] From step 2 onwards, the position control during 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 process. In accordance with the invention, this is made possible by the force control functionality during a movement up to a fixed stop to which a setpoint corresponding to that of an FSW force has been set, and not that corresponding to a clamping force or contact with a stop.

[0134] Steps 4, 5 and 6 involve moving the tool 500' and / or the parts PI and P2 to be welded along one or more axes perpendicular to the axis of rotation of the tool FSW 500' for the purpose of achieving a circular trajectory of the weld S.

[0135] Step 6 defines the end of the weld, the circular trajectory having passed the tool 500' over the beginning of the weld bead.

[0136] Force control is abandoned at point 6. A retraction movement, by translational movement with position control on the axis parallel to the axis of rotation of the FSW tool until the FSW tool is fully retracted 500' from the welded area S, completes the process at step 7.

[0137] The FSW 500 tool can then be replaced by a machining tool to machine the blunder created.

[0138] Next, as regards the other functions to be ensured for the FSW, in particular the taking over of radial forces, the rotation speed of the tool or the control of the temperature will be managed by the Spindle element (the radial forces will also be taken over by the working axes of the machine used).

[0139] The diagrams in Figures 9 and 10 illustrate the speed management during the process.

[0140] Figure 9 shows the speed control on axes perpendicular to the axis of rotation of the tool according to the cycle times of an FSW process according to the invention where:

[0141] - during phases 1 to 2, the advance speed of the axes perpendicular to the axis of The rotation of the tool is controlled by the numerical control according to a programmed trajectory and feed rate;

[0142] -during phases 3 to 6, the programmed feed rate of the axes perpendicular to the axis of rotation of the tool is modulated to regulate the welding force according to a programmed welding force setpoint;

[0143] - during phases 6 to 7, the advance speed of the axes perpendicular to the axis of The rotation of the tool is again controlled by the numerical control according to a programmed trajectory and feed rate.

[0144] Figure 10 shows the management of translational speeds on the axis parallel to the axis of rotation of the tool according to the cycle times of an FSW process where:

[0145] - during phases 1 to 2, the feed rate along the axis parallel to the axis of rotation of The FSW tool is controlled by the numerical control until the tool pin makes contact with the area to be welded, following a programmed trajectory and speed.

[0146] - during phases 2 to 3, the feed rate along the axis parallel to the axis of rotation of The FSW tool is modulated to regulate the fusion force to a programmed fusion force setpoint until the tool shoulder contacts the area to be welded,

[0147] - during phases 3 to 7, given that the weld path lies 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 removal movement of the tool.

[0148] It is understood that the device described and illustrated above was done so for the purpose of disclosure rather than limitation. Of course, various modifications, alterations, and improvements may be made to the above examples without departing from the scope of the invention.

Claims

Demands

1. Machining machine tool (M) equipped with - a tool holder spindle (100) pre-formed with a cavity to accommodate a plurality of tools to be driven in rotation about the axis of the spindle, - a workpiece holder module (200), - a sub-assembly (210) for guiding and moving the spindle in translation towards the workpiece holder module and / or from the workpiece holder module towards the spindle along an axis parallel to the axis of the spindle (100), - a numerical control (C) implementing in particular for said sub-assembly (210) for guiding and moving, a position control system as well as a function for controlling and managing the force during movement up to a fixed stop,CHARACTERIZED IN THAT it accommodates and drives in rotation 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 spindle footprint (100), the rotational drive driving in rotation the pin (511) and the shoulder (512), the force required to implement a friction stir welding process being measured and maintained for the purpose of creating force control during the contact between the tool (500) and the parts to be joined by the force control functionality during movement to a fixed stop.

2. Machine tool (M) according to claim 1, CHARACTERIZED IN THAT said subassembly (210) for guiding and moving in translation of the spindle (100) towards the workpiece holder module (200) and / or of 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 THE FACT THAT said fingerprint is that which corresponds to the HSK100 standard.

4. A 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 exploiting for this purpose the functionality of mastering and controlling the force during a movement up to a fixed stop, -Machining operation with position control on the axis parallel to the axis of rotation of the tool (500).

5. A 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 (511') rotating in the spindle cavity (100'), - rotation of the friction stir welding tool (500') around 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 (500') is in contact with the area to be welded, - abandonment of said position control on the axis 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 a setpoint corresponding to that required for the friction stir welding process, - movement of the friction stir welding tool (500°) and / or the area to be welded along one or more axes perpendicular to the axis of rotation of the friction stir welding tool (500°) for the purpose of carrying out the weld, - end of welding, - abandonment of force-dependent control, - withdrawal by translational movement and with position control on the axis parallel to the axis of rotation of the friction stir welding tool (500') until complete separation of the friction stir welding tool (500') from the welded area.

6. A working method according to claim 5 wherein the machine tool includes a means of modulating the feed rate on its axes of movement, CHARACTERIZED IN THAT it includes an operation of modulating the speed of movement along the axes of movement not subject to force control.

7. Working method according to claim 6, CHARACTERIZED IN THAT it consists, during welding, of modulating the speed of movement of the friction stir welding tool (500') along 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. A working method according to claim 6 wherein the machine tool includes a means for measuring the current consumed by the sub-assemblies for setting in motion along the axes perpendicular to the axis of rotation of the friction stir welding tool (500'), CHARACTERIZED IN THAT it consists, during welding, of controlling the forces on the axes of motion not subject to the force control by measuring the current at the current control level supplying the means for setting in motion 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 piloting 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 welding operation.

10. A working method according to any one of claims 5 to 8, characterized in that the approach operation by translational movement with position control on the axis parallel to the axis of rotation of the friction stir welding tool (500') until contact of the shoulder (512) of the friction stir welding tool (500') with the area to be welded comprises the following operations: - controlling the feed rate of the axis parallel to the axis of rotation of the friction stir welding tool (500') until contact of the pin (511') of the friction stir welding tool (500') with the area to be welded, then - modulation of the feed rate of the axis parallel to the axis of rotation of the friction stir welding tool (500') to regulate the fusion force to a programmed fusion force setpoint until the shoulder (512') of the friction stir welding tool (500') is in contact with the area to be welded.

11. A friction stir welding tool (500) for carrying out the friction stir welding operations of the process according to any one of claims 4 to 10 performed 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 IN THAT it comprises a thermal insulator (530) between the first end (510) and the interface (521).

12. Tool (500) according to claim 11, CHARACTERIZED IN THAT it is preformed of 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 IN THAT thermal insulation inserts (532) are interposed between said discs (531).

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