WO2018215446A1 - Lathe intended for in-situ use for machining an industrial part, and associated machining method - Google Patents

Abstract

The invention concerns a lathe (1) intended for machining an industrial part (2), the industrial part extending, from a tubular end (3), around a central axis (Z), the lathe comprising: a first motor (11), capable of rotating a plate (19) about an axis of rotation (Δ); a cutting tool (23), secured to the plate (19); a second motor (12), capable of moving the cutting tool (23) axially in translation parallel to the axis of rotation (Δ); a third motor (13), capable of moving the cutting tool (23) radially in translation perpendicular to the axis of rotation (Δ); a holding element (30), capable of attaching the lathe to the industrial part, such that the axis of rotation of the lathe (Δ) is parallel to the central axis (Z); such that, when the lathe is attached to the part, the cutting tool is capable of being moved against the tubular end (3), and of being actuated in rotation about said end, and in translation parallel to and perpendicular to the central axis (Z), so as to machine the industrial part from said end. The lathe is controlled according to an automatic sequence of steps allowing the part to be automatically machined according to predetermined profile shapes.

Description

 Lathe for in-situ use for machining an industrial part, and associated machining method

Description

TECHNICAL AREA

 The technical field of the invention is the automated machining of industrial parts such as tubes, and in particular the in-situ realization of chamfers prior to a welding operation.

PRIOR ART

 Successful welding between two tubes requires prior machining of their respective ends. The machining can be:

 a delignage: it is a question of adjusting the internal diameter of the tube with respect to a particular internal profile;

 chamfering: this involves machining the outside diameter of the tube relative to a particular external profile.

 Deligning and chamfering operations consist in modifying the thickness of the tube, from an end of this tube, according to a predetermined profile. The profiles must be made precisely, according to precise geometrical parameters and codified in technical specifications. We distinguish different forms of profiles, and for each profile form, different parameters. The type of profile, and its parameters, are determined according to the weld to be produced, and the characteristics of the tubes to be welded (materials, diameter, thickness, etc.).

 The quality of the weld depends largely on the quality of the machining thus achieved, in particular the precision with which the profiles have been machined. The machining is generally performed in situ, in industrial environments that can be constraining in terms of space, noise, or other difficult conditions, for example a high temperature or a high level of irradiation. Its execution is also constrained by time because it is part of a series of operations executed in series. In addition, it is a precision job, requiring the use of qualified and experienced staff.

 It is also necessary to have a sufficiently compact and lightweight equipment to be easily transported and moved in an industrial facility.

CN205733284 discloses a lathe for performing chamfering operations. The chamfer is made by applying a cutting tool, the shape of which corresponds in profile, against you must be chamfering. Such a method requires the use of powerful engines. Therefore, the ride is heavy and not suitable for nomadic use.

 EP2644301 discloses a latch that can be attached to a bee. The lathe has an axis of rotation so that when the lathe is fixed on the be, its axis of rotation is merged with the axis around which it extends. The lathe comprises a cutting tool, the last being movable in rotation about the axis of rotation of the lathe, and in translation parallel and perpendicular to the axis of rotation of the lathe. The tour described in this document lends itself to nomadic use.

 Document US2008 / 0166696 discloses a lathe for cutting an end of an object into a predetermined shape.

 The inventors have developed a compact tower, inexpensive, and adapted to nomadic use, designed to allow optimized management of the cutting tool. The lathe guarantees a quality machining without the need for permanent presence of qualified operators.

SUMMARY OF THE INVENTION

 A first object of the invention is a lathe, in particular a nomad lathe, for machining an industrial part, the industrial part extending, from a bunted end, around a central axis, the lathe comprising:

 a first motor adapted to rotate a platen about an axis of rotation; - A cutting tool, integral with the plate;

 a second motor capable of axially translating the cutting tool parallel to the axis of rotation;

 a third motor, able to radially translate the cutting tool, perpendicular to the axis of rotation;

 - A holding element, adapted to fix the lathe to the industrial part, so that the axis of rotation of the lathe is parallel or coincides with the central axis;

so that when the lathe is fixed to the workpiece, the cutting tool is adapted to be moved against the end tu bulaire, and to be actuated in rotation around the end tu bulaire, and in translation parallel and perpendicular to the central axis, so as to machine the workpiece from said end tu bulaire.

 The tour may include a microprocessor, connected to a memory, configured to perform the following operations:

a) taking into account geometrical parameters of the end tu bulaire; b) selecting a machining profile from among several predefined machining profiles and stored in the memory, and taking into account geometric parameters of the selected profile;

 c) from the parameters taken into account during steps a) and b), defining a sequence of movements of the cutting tool;

 d) defining an initial position of the cutting tool with respect to the tubular end; e) when the cutting tool is disposed in the initial position, actuating the first motor, the second motor and the third motor so as to drive the tool according to the displacement sequence defined in step c) and to machine , from the tubular end, the industrial part according to said sequence.

 According to such a sequence of steps, the machining of the end of the be can can be performed in situ, in an automated manner. The machining, and in particular its parameters, can be memorized. Machining can be done without the need for qualified operators.

 Nomadic tour means an easily transportable tower, to be deployed in an industrial installation and be attached to an industrial part, including a tube, in the facility. The mass of the tower is preferably less than 250 Kg, or even 100 Kg. In-situ means on site, without requiring a transfer of the workpiece outside the installation in which it is used.

 According to one embodiment, the lathe may be such that the third motor is actuated by a microcontroller, said radial translation microcontroller, integral with the plate. Thus, the radial translation microcontroller follows a rotational movement when the plate is rotated by the motor. The radial translation microcontroller is then configured to:

 transmitting, to the microprocessor, a position of the cutting tool, along a radial translation axis, perpendicular to the axis of rotation;

 receive instructions from the microprocessor, and, according to the instructions received, control the activation of the third engine.

 The radial translation microcontroller may comprise or be connected to encoders for determining a position of the cutting tool along the radial translation axis.

The lathe may comprise a rotating commutator, comprising a fixed stator with respect to the first and second motors, and a rotor integral with the plate, adapted to be rotated by the latter, the rotary commutator providing an electrical connection between upstream conductors emerging from the stator and downstream conductors extending from the rotor to the radial translation microcontroller. The number of electrical connections provided by the rotating collector is preferably less than or equal to 6. An advantage of having a radial translation microcontroller secured to the plate, and mobile in rotation with the latter, is to reduce the number of connections electrical work done by the rotating collector.

 The microprocessor is preferably configured to implement the machining method described below.

 A second object of the invention is a method of machining an industrial part, the industrial part extending from a tubular end around a central axis, the machining being performed by a cutting tool. , the cutting tool being disposed on a lathe, the lathe defining an axis of rotation, the latch being intended to be fixed to the industrial part, so that the axis of rotation of the lathe coincides with the central axis of the tubular end, the turn being and able to move the cutting tool:

 - in rotation about the axis of rotation;

 according to a translation, called axial, parallel to the axis of rotation;

 according to a translation, called radial, perpendicular to the axis of rotation;

the process comprising the following steps:

 a) taking into account geometrical parameters of the tubular end;

 b) selecting a machining profile from predetermined profiles and stored in a memory, then taking into account geometric parameters of the machining profile thus selected;

 c) from the parameters taken into account in steps a) and b), definition by the microprocessor of a sequence of movements of the cutting tool;

 d) defining an initial position of the cutting tool with respect to the tubular end; e) when the cutting tool is disposed in the initial position, actuating the lathe so as to drive the tool according to the sequence of movements defined in step c), so as to form the machining profile, defined during step b), from the tubular end.

 The method may comprise, prior to step d), a dressing, of machining the end tu bulaire in a plane perpendicular to the axis of rotation, so that the latter extends along said plane.

According to one embodiment: the sequence of movements comprises a multitude of elementary sequences, each elementary sequence comprising an axial translation of the cutting tool from the end to the end, each elementary sequence being performed while the cutting tool is driven. in rotation around the axis of rotation of the lathe; between two successive elementary sequences, the cutting tool is translated according to a radial translation.

 During each elementary sequence, the machining may in particular allow the removal of a material thickness less than or equal to 5 mm, and preferably less than or equal to 2 mm, for example 0.1 mm.

 According to one embodiment, during step d), the initial position of the cutting tool is disposed against the tubular end or at a predetermined distance from the latter. This facilitates the positioning of the cutting tool according to the initial position.

 According to one embodiment, the method comprises a finishing machining step f), comprising the application of the cutting tool along the machining profile formed during step e) so as to eliminate discontinuities. of said profile.

 The method according to the second subject of the invention can be implemented using the lathe according to the first subject of the invention.

 The tubular end defines an outer surface and an inner surface. The method may be applied to form a profile along the outer surface and / or along the inner surface. The profile may in particular extend according to a distance, said working distance, less than 20 cm, of the tubular end, parallel to the central axis of the tubular end.

 The industrial part may in particular be a tube, or comprise a tube.

Other advantages and features will emerge more clearly from the following description of particular embodiments of the invention, given by way of non-limiting examples, and shown in the figures listed below.

FIGURES

 Figures 1A, 1B, 2A and 2B form different views of an example of a tower according to the invention, the lathe being mounted on a tube to be machined.

Figures 3A, 3B and 3C show a detail of a carriage for performing a radial translation of the cutting tool carried by the lathe. FIG. 3D shows a first configuration of the cutting tool, intended to form a chamfer, by machining the outer wall of the you are. Figure 3 E shows a second configuration of the cutting tool, intended for a delieving operation, by machining the inner wall of you be.

 FIGS. 4A and 4B illustrate a rotating connector for powering the motor allowing translation of the cutting tool perpendicularly to the rotation axis of a lathe.

 FIG. 5A represents different steps of a method of performing machining, in particular using the lathe as shown in the preceding figures. Figs. 5B, 5C, 5D, 5E and 5F are respectively illustrations of steps 110, 120, 130, 140, 150 described in connection with Fig. 5A.

 FIG. 5G shows a sequence of elementary displacements of the cutting tool so as to obtain a section profile.

DESCRIPTION OF PARTICULAR EMBODIMENTS

 FIGS. 1A and 1B show an example of a tower 1 according to the invention. The lathe 1 is intended to be fixed on an industrial part, which is, in this example, a tu be 2, so that end 3 of the be be machined. The be extends, between an external surface 2.1 and an internal surface 2.2, about an axis, said central axis Z. The lathe 1 has an axis of rotation Δ, so that when the lathe 1 is fixed on the be 2, the axis of rotation Δ is confused with the central axis Z of the be be 2.

 The lathe 1 comprises a shaft 10, the shaft extending along the axis of rotation Δ of the lathe. The tower 1 is fixed to the be 2 by a holding member 30. In this example, the holding member comprises jaws 31, extending from the shaft 10 so as to be in contact with the inner wall 2.2 of the you are, thus ensuring a centering and a maintenance of the lathe 1 on the you are 2. Thus, the lathe 1 is carried by the you be, the axis of rotation Δ of the lathe 1 being coaxial of the axis of central 2. Other holding elements 30, allowing a holding of the turn 1 by the be be 2 are considered, for example a frame enclosing the outer surface 2.1 of you be 2, the frame being connected to the turn 1 by longitudinal struts extending parallel to the axis of rotation Δ of the turn 2.

The lathe comprises a first motor 11, controlled by a microcontroller 11 ', said microcontroller of rotation, and a plate 19. The first motor 11 is adapted to drive the plate 19 in rotation about the axis of rotation Δ. The first motor 11 is connected to a transmission 15, visible in Figure 1B, formed of pinions for transmitting the rotational movement to the plate 19. The transmission 15 is covered by a housing 14. The power of the first motor can be equal to 1.5 kW. It may for example be an electric motor marketed by OM ON under the reference R88K1K530H.

 The lathe comprises a plate 19, adapted to be rotated by the first motor 11. The plate 19 in this example takes a form of disk. The plate 19 serves to support a cutting tool 23 described later.

 The tower 1 comprises a second motor 12, controlled by a microcontroller 12 'said microcontroller axial translation, for driving the plate 19 in an axial translation, parallel to the axis of rotation Δ of the lathe 1. In this example, the platinum moves in translation relative to the shaft 10, the latter being held fixed relative to the tube 2. Under the effect of the axial translation, a first distance di between the plate 19 and the end 3 of the tube 2 , is variable. In this example, the second motor 12 is an electric motor with a power of 750 W. It is for example the engine marketed by MAXON under the reference ECMAX 30L / PM42 24V.

 The tower 1 comprises a third motor 13, intended to control a translation of the cutting tool 23, called radial translation, perpendicular to the axis of rotation Δ of the lathe 1. This is a power electric motor 240 W. In this example, it is the engine marketed by MAXON under the reference ECMAX 22L / PM22 24V. The cutting tool 23 is fixed to a tool support 22, the latter being carried by a carriage 20. The third motor drives the displacement of the carriage 20 in radial translation. The carriage 20 and the tool support 22 are described in connection with FIGS. 2A, 2B and 3A to 3E.

 The lathe comprises a gripping element 16, in this example a handle, allowing manual gripping of the lathe or with the aid of a lifting means. It also comprises a rotating manifold 18, allowing a power supply of a radial translation microcontroller 13 ', described below. The rotating manifold is described in connection with FIGS. 4A and 4B.

The latch comprises a microprocessor 40, configured to execute instructions, encoded in a memory 41, for defining and controlling the movement of the cutting tool 23 relative to the tube 2, as described below, in connection with the Figures 5A to 5G. The microprocessor is connected to a screen 42, to follow the setting of the machining and its progress. The screen is preferably a touch screen, which allows a simple communication of an operator with the microprocessor 40. The microprocessor 40, the memory 41 and the screen 42 then form a control interface of the lathe 1. FIGS. 2A and 2B show the cutting tool 23 mounted at one end of a tool support 22. The tool support 22 is fixed to a carriage 20, the carriage being mounted movably in radial translation, perpendicular to the axis of rotation Δ of the lathe 1. The carriage 20 moves along two rails 25, arranged on the plate 19. It is driven in translation by the third motor 13, through a worm 24. The radial translation has the effect of modifying a second distance d2, between the cutting tool 23 and the rotation axis Δ of the turn 1, as shown in Figure 2B. The plate 19 comprises a counterweight 29, preferably diametrically opposed to the third motor 13.

 FIGS. 3A, 3B and 3C show the cutting tool 23, mounted at the end of the tool support 22, the latter being inserted into an opening 28 formed in the carriage 20. As shown in FIG. 3B, the carriage may include a plurality of openings 28 adapted to receive the tool support 22, so as to adapt the translational movement of the cutting tool 23.

 The third motor 13 is controlled by a radial translation microcontroller 13 '. The microcontroller radial translation 13 'is mounted integral with the plate 19. It is rotatable about the rotation axis Δ of the lathe 1. The radial translation microcontroller 13' receives instructions from the processor 40, and operates the third motor 13 according to said instructions. The radial translation microcontroller 13 'comprises encoders 26, for defining the position of the carriage 20 along the axis of the radial translation. Advantageously, the radial translation microcontroller 13 is connected to at least one so-called end-of-travel sensor 27, so as to determine the position of the carriage when the latter reaches a maximum displacement along the axis of the radial translation. Such a sensor can make it possible to initialize the encoders 26 during an initialization phase. Thus, depending on the position of the carriage 20, and instructions received from the microprocessor 40, the radial translation microcontroller 13 'actuates the third motor 13, in one direction or the other, so as to adjust the second distance d2, whether to reduce it, to increase it or to keep it constant.

 The microprocessor 40 is connected to all or part of the microcontrollers 11 ', 12' and 13 'by wire connection or by wireless link.

Figures 3D and 3E show different arrangements of the cutting tool 23 on the support 22. In this example, the cutting tool is a plate, at least one edge is salient. The assembly of FIG. 3D corresponds to an arrangement adapted to the production of a chamfer, the cutting tool 23 acting on the outer wall 2.1 of the tube 2. The assembly of FIG. 3E corresponds to an arrangement adapted to the production of a chamfer 'a delignage, the cutting tool 23 acting on the inner wall 2.2 of the tube 2. It is possible to have a mixed support, having, at its end, two cutting tools respectively oriented in two opposite directions, one being intended for chamfering, the other being intended for delineation.

 The instructions from the microprocessor 40 reach the radial translation microcontroller 13 'through a rotating manifold 18 shown in Figs. 4A and 4B. It may for example be a rotary manifold type MOFLON MT100 P0205-S 4. Such a collector provides an electrical connection between a fixed part, usually designated by the term stator and a movable part, usually designated by the term rotor , the latter being intended to rotate about the axis of rotation Δ during operation of the lathe 1. It may for example be a rotary ring manifold. It allows an electrical connection between conductors, said upstream conductors 17, fixed relative to the first motor and the second motor, and conductors, said downstream conductors 17 ', extending along the plate 19, towards the radial translation microcontroller 13 . The downstream conductors 17 'are in particular intended for feeding and controlling the third electric motor 13.

 The arrangement of the radial translation microcontroller 13 'on the plate 19, that is to say downstream of the rotating connector 18, between the plate 19 and the cutting tool 23, makes it possible to minimize the number of electrical connections provided by In the example shown, the rotating manifold 18 provides a connection respectively between five upstream conductors 17 and five downstream conductors 17 '. Two of said conductors conduct a power signal for the power supply of the third motor 13. Two conductors carry a control logic signal, CAN bus type (acronym for Controller Area Network), for the radial translation microcontroller 13 ' . A conductor is preferably connected to a ground. The minimization of the number of electrical connections makes it possible to reduce the size of the rotary commutator 18, as well as its cost. It also improves the reliability of the lathe, too many electrical connections in a rotating manifold can affect reliability.

FIG. 5A represents the main steps allowing the control of the lathe 1. The devices known from the prior art also comprise control interfaces, the latter allowing a manual adjustment, or even a programming in time, of cutting parameters, for example the speed of rotation of the lathe or the speed of axial translation and radial translation of the cutting tool. Such settings assume a certain expertise on the part of an operator, since as indicated in connection with the prior art, the Cutting parameters vary depending on the machined material, tube dimensions and profile to be made.

 In order to facilitate the use of the lathe, the inventors have devised an algorithm allowing an automatic parameterization of the lathe, and facilitating the implementation of the latter, according to the steps described below:

 Step 100: positioning the lathe. This step consists in fixing the tower 1 on the tube 2, using the holding element 30, so that the tower 1 is carried by the tube 2.

 Step 110: referencing the operation. During this step, the name of the operator OP and the reference EF of the operation carried out is given for traceability purposes. The taking into account, by the microprocessor 40, of these data, can be obtained through the screen shown in Figure 5B.

Step 120: Tube parameters. During this step, information is given about the parameters relating to the tube 2: the material Mat, the internal diameter Om _t , the external diameter O _ext , possibly the thickness ε. FIG. 5C shows the interface appearing on screen 42 during the definition of these parameters.

 Step 130: Select the profile. During this step, a profile P is selected from a PROFILE profile database stored in memory. The selection of the profile P depends in particular on the type of welding which will be carried out thereafter. Figure 5D shows the interface appearing on screen 42 when selecting a profile shape. Figure 5E schematizes an example of a profile. For each selected profile, a list of specific parameters of the profile is completed. FIG. 5E represents parameters T, H, R, Θ of a profile to be formed. These parameters correspond respectively to a residual thickness, a working distance along the central axis of the tube, a radius of curvature and an angle.

Step 140: Movement sequence. Given the dimensions of the tube and the selected profile, and taking into account the dimensions of the cutting tool 23, the microprocessor 40 determines a displacement sequence S of the cutting tool 23 against the tube 2. A sequence of displacement s comprises a plurality of elementary displacement sequences S _n . Each elementary displacement sequence S _n comprises an axial translation of the cutting tool 23 parallel to the axis of rotation Δ, from the end 3, during which an elementary thickness of material is removed. It also comprises an axial translation in opposite direction, so as to bring the cutting tool 23 of the end 3 of the tube 2. A radial translation of the cutting tool in the direction of the axis of rotation Δ is performed between two successive elementary sequences S _n , S _{n + 1} . So, step by step, the succession of the elementary sequences S _n makes it possible to obtain the desired profile, as described in FIG. 2G.

The elementary thickness of material removed during each elementary sequence S _n is generally between 0.05 mm and 2 mm. The withdrawal, during each elementary sequence S _n of a small thickness of material, allows the realization of different profile shapes. The path of the cutting tool 23 during the various elementary sequences can successively remove layers of material, to obtain the desired profile. The successive withdrawal of a small thickness of material allows the use of low power engines, making the tower 1 lighter and more easily transportable. When the machining performed is a chamfer, the cutting tool is moved closer to the axis of rotation between two successive elementary sequences. When the machining performed is a delignage, the cutting tool is moved away from the axis of rotation between two successive elementary sequences.

 Step 140 may be preceded by a dressing operation, aiming to adjust the end 3 so that it extends in a plane perpendicular to the axis of rotation of the lathe. This operation is performed by moving the cutting tool perpendicularly to the axis of rotation Δ.

 Step 150: Initialization. During this step, shown schematically in FIG. 5F, the microprocessor 40 determines an initial position at which the cutting tool 23 must be arranged. This initial position is generally placed at the end 3 of the tube 2, or at a predetermined distance from this end. The operator moves the cutting tool 23 to the initial position determined by the microprocessor 40 and confirms that the cutting tool is well positioned at said initial position.

Step 160: machining. During this step, illustrated in FIG. 5G, the microprocessor generates control instructions for the rotation microcontroller 11 ', the axial translation microcontroller 12' and the radial translation microcontroller 13 ', so that the tool section 23 performs the displacement sequence calculated in step 140. FIG. 5G shows the various elementary sequences Si ... S _n ... S _N constituting a displacement sequence S. During each elementary sequence, a Thick material thickness is removed, typically between 0.05 mm and 2 mm, as previously described. The fact of performing different elementary sequences S _n to successively remove different layers of material makes it possible to use the same cutting tool 23 to produce different profile shapes. In this example, the cutting tool 23 is a simple plate: the invention allows the use of a single inexpensive cutting tool, the realization of different profiles being possible by the succession of elementary sequences S _n , during which a small thickness of material is removed.

 During each elementary displacement sequence, the microprocessor 40 receives information from the microcontrollers of rotation, axial translation and radial translation and, based on this information, generates a control signal to the microcontrollers so as to actuate the motors to move the microcontroller. cutting tool according to the profile selected and parameterized. Preferably, during an elementary displacement, a single translation is controlled, whether it is an axial translation or a radial translation. During each elementary displacement, the rotational speed of the lathe as well as the translation speed, whether axial translation or radial translation, is automatically calculated by the microprocessor 40, according to known standards. of the skilled person. The calculation of these speeds takes into account in particular the material constituting the workpiece 2, as well as the diameter of the tubular end 3. The automatic calculation of the speeds facilitates the implementation of the lathe. The rotational or translation speeds calculated automatically by the microprocessor 40 can be adjusted manually by an expert operator.

 At the end of the elementary sequences, the desired profile is obtained at a step of discretization, the step of discretization corresponding to the thickness of the material layer removed during each elementary sequence. Such a solution is preferable to the use of cutting tools of different shapes, in which each cutting tool takes a specific shape of profile.

 Step 170: Finishing machining The execution of the machining sequence, according to step 160, can leave a coarse surface condition, due to the successive translations of the cutting tool during each elementary machining sequence, which generates discontinuities. surface condition. During this step, the cutting tool is applied along the profile obtained following step 160, so as to reduce discontinuities and improve the surface state of the profile. During this step, the control of the second motor and the third motor is synchronized, these two motors being simultaneously actuated. Step 170 is optional.

Step 180: traceability. The execution of the machining sequence can be recorded in a memory, including the information relating to the operation taken into account during steps 110, 160 or 170. This allows the preparation of summary reports relating to the machining done. Step 180 is optional. Although described in connection with the making of a chamfer on the outer surface 2.1 of a tube, as shown in FIG. 5G, the above steps can be applied to the production of a profile on the inner surface 2.2. a tube, from the end 3.

 The invention may be implemented for the in-situ machining of tubes or other industrial parts having a tubular end, to shape said end prior to performing welds. It can be flanges, It allows, from stored configurable profiles, to perform this type of machining in a simple, automatic and controlled. It is particularly suitable for maintenance operations in complex industrial sites, in the field of chemistry, agri-food, oil industry or nuclear power.

Claims

1. A method of machining an industrial part (2), the industrial part extending, from a bulaire end (3), about a central axis (Z), the machining being carried out by a cutting tool (23), the cutting tool being arranged on a lathe (1), the lathe defining an axis of rotation (Δ), the lathe being fixed to the industrial part, so that the axis of rotation rotation of the lathe (Δ) coincides with the central axis (Z), the lathe being able to move the cutting tool:  in rotation around the axis of rotation (Δ);  according to a so-called axial translation, parallel to the axis of rotation;  in a so-called radial translation, perpendicular to the axis of rotation; the lathe having a processor (40) connected to a memory (41); the process comprising the following steps:  a) taking into account geometrical parameters of the end tu bulaire (3);  b) selecting a machining profile (P) from among predetermined profiles and stored in the memory (41) and taking into account the geometrical parameters of the machining profile thus selected;  c) from the geometrical parameters taken into account during steps a) and b), definition by the microprocessor (40) of a sequence of movements (S) of the cutting tool; d) defining an initial position of the cutting tool with respect to the end tu bulaire (3);  e) when the cutting tool is disposed in the initial position, actuating the lathe (1) so as to drive the cutting tool (23) according to the sequence of movements (S) defined in step c), in order to form the machining profile (P), defined in step b), from the tufted end (3), the machining being a trimming or chamfering, the method being such that the sequence of movements comprises a multitude of elementary sequences (S _n ), each elementary sequence comprising an axial translation of the cutting tool (23) from the end tu bulaire (3) or towards the end tu bulaire, each elementary sequence being performed while the cutting tool (23) is rotated about the rotation axis (Δ) of the lathe; and wherein between two successive elementary sequences, the cutting tool (23) is translated in a radial translation, perpendicular to the axis of rotation (Δ). 2. Method according to claim 1, wherein the lathe (1) is carried by the industrial part (2). 3. Method according to claim 1 or claim 2, wherein successive elementary sequences lead to the removal of a layer of material less than 2 mm thick. 4. Method according to any one of the preceding claims, wherein during step d), the initial position of the cutting tool is disposed against the tubular end (3) of the workpiece or at a predetermined distance said tubular end (3). 5. Method according to any one of claims 1 to 4, comprising a finishing step f), comprising the application of the cutting tool along the profile formed in step e) so as to eliminate discontinuities of said profile. The method of any one of the preceding claims, wherein the tubular end defines an outer surface and an inner surface, the method for forming a profile along the outer surface and / or along the inner surface. 7. Method according to any one of the preceding claims, wherein the profile may extend according to a working distance of less than 20 cm from the tubular end, parallel to the central axis (Z). The method of any one of the preceding claims, wherein the lathe comprises:  a first motor (11), adapted to rotate a platen (19) about the axis of rotation (Δ), the cutting tool (23) being integral with the plate (19);  a second motor (12), able to translate axially the cutting tool (23) parallel to the axis of rotation (Δ);  a third motor (13), able to radially translate the cutting tool (23) perpendicularly to the axis of rotation (Δ);  - A holding element (30), adapted to fix the lathe to the industrial part, so that the axis of rotation of the lathe (Δ) is parallel to the central axis (Z); so that when the lathe is attached to the workpiece, the cutting tool is adapted to be moved against the tubular end (3), and to be rotated about the tubular end, as well as translation parallel and perpendicular to the central axis (Z). 9. The method of claim 8, wherein the third motor (13) is actuated by a microcontroller (13 '), said radial translation microcontroller, integral with the plate (19). The method of claim 9, wherein the radial translation microcontroller (13 ') is configured to:  transmitting to the microprocessor (40) a position of the cutting tool along a radial translation axis perpendicular to the axis of rotation (Δ);  - Receive instructions from the microprocessor (40), and, according to these instructions, control the activation of the third motor (13). 11. The method of claim 10, comprising encoders (26) for determining a position of the cutting tool along a radial translation axis, perpendicular to the axis of rotation, the encoders being included in the microcontroller. radial translation (13 ') or connected to said microcontroller (13'). 12. Method according to any one of claims 8 to 11, comprising a rotating collector (18), comprising a stator fixed relative to the first and second motors (11, 12), and a rotor secured to the plate (19) and capable of being rotated by the first motor (11), the rotary commutator providing an electrical connection between upstream conductors (17) opening out from the stator and downstream conductors (17 ') extending from the rotor towards the microcontroller of radial translation (13 '), the number of electrical connections provided by the rotating collector being preferably less than or equal to 6. 13. Lathe (1) for machining an industrial part (2), the industrial part extending from a tubular end (3) around a central axis (Z), the lathe comprising:  a first motor (11) capable of rotating a plate (19) about an axis of rotation (Δ);  a cutting tool (23) integral with the plate (19);  a second motor (12), able to translate axially the cutting tool (23) parallel to the axis of rotation (Δ);  a third motor (13) capable of radially translating the cutting tool (23) perpendicularly to the axis of rotation (Δ);  a holding element (30), able to fix the lathe to the industrial part, so that the axis of rotation of the lathe (Δ) is parallel to the central axis (Z); so that when the lathe is attached to the workpiece, the cutting tool is adapted to be moved against the tubular end (3), and to be rotated about the tubular end, as well as translation parallel and perpendicular to the central axis (Z), so as to machine the industrial part from said tubular end, the lathe being characterized in that it comprises a microprocessor (40) capable of implementing the steps a) to e) of a method according to any one of claims 1 to 11.