MACHINING SPINDLE

Description

Technical field

[0001] The present invention relates to a machining spindle comprising a housing containing an electric motor rotating a machining tool, such as an electrospindle and a motorized spindle.

[0002] Also disclosed are a monitoring device for a machining spindle and a method for updating a machining spindle not forming part of the claimed invention. State of the art

[0003] The production of parts, particularly those of small size and high added value, is often carried out using machining spindles.

[0004] The management of all the machining spindles in a workshop (i.e. a spindle park) thus becomes necessary in order to guarantee at all times the availability of a sufficient number of spindles allowing correct machining operations and conforming to the machining specifications, which implies planning of revision operations as well as preventive replacement for each spindle in the workshop.

[0005] US2009267429 describes a spindle for a machine tool comprising an RFID chip that can be read via a reading element. The RFID chip may contain spindle manufacturing data, such as its serial number, its issue date, its warranty details, as well as machining data, such as rotational speed, torque and parameter sets for a numerically controlled machine tool.

[0006] DE 10 2010 054 999 A1, EP 2 446 998 A1 and DE 10 2014 116 861 A1 also disclose machining spindles. Brief summary of the invention

[0007] An aim of the present invention is to propose a machining spindle, in particular a motorized spindle or electrospindle, which allows easier management of the latter among a fleet of machining spindles in a workshop compared to known machining spindles.

[0008] Another aim of the invention is to propose a spindle for machining, in particular a motorized spindle or electrospindle, which allows rationalization of revision operations and preventive replacement of the spindle.

[0009] According to the invention, these aims are achieved by means of the spindle according to claim 1 and the machining set according to claim 12. The dependent claims describe particular embodiments of the invention.

[0010] This solution has the particular advantage over the prior art of having an indicator of the wear and / or functional state of the spindle, which makes it possible to dynamically adapt the handling, revision and replacement plan of the spindle.

[0011] In a particular embodiment of the invention, the machining spindle saves technical, operational and / or machining data which facilitate its operation as well as handling, revision and diagnostic operations.

[0012] In a particular embodiment of the invention, the machining spindle allows predictive maintenance based on analyses of data determining the rotation state of the motor and / or the machining tool, in particular by vibration and / or temperature sensors.

[0013] Also disclosed is a monitoring device for a machining spindle. This solution makes it possible to update a machining spindle on the market so as to allow easier management of the latter among a fleet of machining spindles in a workshop as well as rationalization of revision operations and preventive replacement of the spindle. Brief description of the figures

[0014] Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which: there figure 1 illustrates a first embodiment of a machining spindle, according to the invention; the Figures 2 and 3 illustrate a second and a third embodiment of a machining spindle, according to the invention; the Figures 4 and 5 illustrate examples of management of a spindle, respectively of a spindle park of a workshop, according to the invention. Example(s) of embodiment of the invention

[0015] There figure 1illustrates a spindle 1 for machining, in particular an electrospindle or motorized spindle. Spindle 1 is intended to machine a part (not illustrated) using a rotating machining tool 12 which is driven in rotation by an electric motor 11 equipping spindle 1, through a shaft 15.

[0016] The machining tool 12 equipping the spindle can be any type of tool operating by rotation, in particular a turning, milling, drilling, grinding, cutting, and / or turning tool.

[0017] Spindle 1 for machining the figure 1 is intended for machining parts, such as watch and jewelry parts. The spindle is generally mounted movably on a base configured to be fixed and / or placed on a work table. The movement of the spindle relative to the base is carried out by a displacement mechanism, controlled electrically or manually by an operator.

[0018] The spindle 1 comprises a housing 10 enclosing the electric motor as well as a part of the shaft 15 so as to protect them against the intrusion of dust and / or liquids while guaranteeing protection of the user against involuntary contact with moving components or components made incandescent by the motor and by the machining carried out through the machining tool 12. The shaft is connected to the housing by means of a pivot connection, for example produced by one of the bearings 16, preferably rolling bearings, operating on two remote portions of the shaft.

[0019] The motor 11 is powered by a power supply 14 configured to be connected to a power supply network through a cable 13. The power supply can be housed outside or inside the spindle housing.

[0020] Pin 1 includes a 20 electronic run time counter.

[0021] Counter 20 includes: a first electronic circuit 24, 240, 241, 242 arranged to determine a rotation state of the motor 11 and / or of the machining tool 12; a second electronic circuit 22 configured to carry out a count of the operating time of the spindle from signals supplied by this first electronic circuit; and a communication module 21 arranged to transmit said operating time through a communication interface with or without wires.

[0022] A rotational state of the motor 11 and / or the machining tool 12 indicates a rotational movement of a rotating part, in particular the rotor 111, the motor and / or the machining tool 12 around its axis of rotation. Optionally, a rotational state may indicate a rotational movement of a rotating part, in particular the rotor 111, the motor and / or the machining tool 12 which exceeds a predefined rotational speed threshold, in particular allowing, or characterizing, a predefined machining operation.

[0023] A rotational state of the motor 11 and / or the machining tool 12 can be determined by means of a vibration sensor 240 arranged to sense vibrations affecting the housing 10, one or more bearings, the electric motor 11 and / or the machining tool of the spindle. A rotation during a predefined machining operation can thus be determined by a predefined range of amplitudes, frequencies and / or directions of the vibrations.

[0024] Alternatively or additionally, a rotational state of the motor 11 and / or the machining tool 12 can be determined by means of an inductive circuit or a magnetic field sensor 242 arranged to capture a magnetic and / or electromagnetic field generated by the electric motor 11 (in particular by its stator 112 and / or rotor 111) and / or a (component of a) power supply 13, 14 of the latter when the motor is powered on.

[0025] Alternatively or additionally, a rotational state of the motor 11 and / or the machining tool 12 may be determined by means of a thermal sensor 241 arranged to sense a temperature of the housing 10, one or more bearings 16, the electric motor 11, the machining tool and / or the spindle bearing(s), in particular a temperature rise caused by the motor when it is actuated, by the machining tool performing machining on a part, and / or by the rotation of the bearing(s).

[0026] The communication of data from the first electronic circuit can be carried out to the second electronic circuit and / or to the communication module 21 by wire or wirelessly.

[0027] The spindle includes a power source to power the spindle counter.

[0028] In the embodiment illustrated by the figure 1, the first electronic circuit comprises, for example, a vibration sensor 240, a magnetic field sensor 242 and a thermal sensor 241.

[0029] The vibration sensor 240 is fixed to a wall, internal or external, of one of the bearings 16. It comprises an accelerometer capturing vibrations of the bearing, preferably radial accelerations relative to the axis of rotation of the motor 11 and / or the shaft 15.

[0030] The magnetic field sensor 242 is attached to a wall of the motor and / or its power supply. It comprises an inductive or Hall effect sensor, arranged to sense a magnetic and / or electromagnetic field of the electric motor and / or its power supply.

[0031] The thermal sensor 241 is attached to a wall of the motor, in particular its stator 112. It comprises a temperature sensor arranged to sense a temperature of the electric motor and / or a component of the spindle.

[0032] The second electronic circuit 22 may comprise a programmable or dedicated unit, such as a microcontroller, a microprocessor, a DSP, an FPGA or a chip (integrated circuit).

[0033] Advantageously, the second electronic circuit 22 is configured to determine a machining force, a machining torque and / or a workload from signals provided by said first electronic circuit 24.

[0034] Advantageously, the second electronic circuit 22 is configured to determine a number of working cycles and / or a number of parts machined using the spindle from signals provided by said first electronic circuit 24.

[0035] Advantageously, the second electronic circuit 22 is configured to determine a state of wear of the spindle 1, in particular of the machining tool 12, of the electric motor 11 and / or of one or more bearings 16 (in particular of the bearings of the bearing(s)) from signals supplied by said first electronic circuit 24 and / or the operating time of the spindle.

[0036] A machining tool wear condition is a physical condition of the machining tool, in particular of a machining surface, which differs from its condition when it is (first) put into operation and is characterized by physical values within a predefined range.

[0037] Advantageously, the second electronic circuit 22 can be configured to generate a first (digital) wear indicator in the absence of detection of the wear state (default indicator). This first wear indicator indicates a normal wear state, that is to say which does not require an overhaul and / or replacement of the spindle, or even of these components.

[0038] Advantageously, the second electronic circuit 22 is configured to generate a second (digital) wear indicator in response to a detection of the wear state. This second indicator indicates an excessive state of wear which affects or may affect the quality of the machining, which makes it necessary to overhaul and / or replace the spindle, or even these components.

[0039] Advantageously, the second electronic circuit 22 is configured to determine an abnormal operating state of the spindle, in particular of the machining tool 12, of the electric motor 11 and / or of one or more bearings 16 (in particular of the bearings of the bearing(s), from signals supplied by said first electronic circuit 24 and / or the operating time of the spindle.

[0040] An abnormal operating state of the spindle, in particular of the machining tool, the electric motor and / or one or more bearings 16, is an operating state which differs from its operating state intended when the spindle was designed.

[0041] Advantageously, the second electronic circuit 22 can be configured to generate a first (digital) operating indicator in the absence of detection of the abnormal operating state (i.e. a normal operating indicator). This first indicator indicates a normal operating state, i.e. one which does not require an overhaul and / or replacement of the spindle, or even of these components.

[0042] Advantageously, the second electronic circuit 22 is configured to generate a second (digital) operating indicator in response to detection of the abnormal operating state (i.e. an abnormal operating indicator). This indicator indicates an abnormal operating state that no longer guarantees the quality of the machining, which requires an overhaul and / or replacement of the spindle, or even of these components.

[0043] The 20 meter of the figure 1may include a data storage memory 23, configured to allow writing and reading of data from the counter 20.

[0044] In particular, the memory 23 is configured to allow the first and second circuits of the meter to write data relating to the meter. The memory 23 is then configured to allow the second circuit of the meter and / or communication module 21 to read all or a subgroup of this data relating to the meter.

[0045] Data communication between the memory 23 and the first and second electronic circuits and the communication module can be carried out by wire or wirelessly.

[0046] This memory allows the saving of technical, operational and / or machining data which facilitates the start-up as well as the handling, revision and diagnostic operations of spindle 1.

[0047] The data stored in said memory include, in particular: operating time, wear condition, abnormal operating condition, number of working cycles and / or number of machined parts.

[0048] The data saved in said memory includes data saved during the manufacture, revision or repair of the spindle, in particular: a numerical identity of the spindle, a serial number, an indication of the spindle manufacturer; an indication of the spindle type; an indication of the maximum number of revolutions of the spindle; an indication of the power, electrical intensity and / or voltage for use of the spindle; an indication of the machine on which the spindle is used; an indication of the position of the spindle on the machine; and / or a history of commissioning, handling and revision of the spindle.

[0049] The pin's digital identity may implement an RFID tag or similar.

[0050] The history may include an indication of: when the spindle was first started, the number of hours at the time of each overhaul, the spindle components that were changed, the reasons for the overhaul, and / or the company that performed the overhaul.

[0051] The communication module 21, possibly through the second electronic circuit in the form of a programmable or dedicated unit, is arranged to transmit this data, or at least a subgroup of this data, saved in the memory through the communication interface with or without wires.

[0052] Advantageously, the communication module 21, possibly through the second electronic circuit in the form of a programmable or dedicated unit, is arranged to transmit the raw data which are delivered by the first electronic circuit 24, 240, 241, 242 (where they have been previously delivered and then stored in the memory), this for diagnostic purposes. This communication can be carried out for example once per hour, per day, per week, or almost continuously.

[0053] In particular, the transmission is activated by receiving a signal and / or a command through the wired or wireless communication interface, or at periodic intervals. Advantageously, a set of signals and / or commands can be defined, each signal and / or command making it possible to trigger a transmission of one or a distinct subgroup of data.

[0054] The wireless communication interface may be a device or module configured to exchange data according to a Bluetooth, ANT, Wi-Fi, LoRa and / or RFID communication standard.

[0055] THE Figures 2 and 3 illustrate two particularly advantageous embodiments of the counter 20.

[0056] According to the invention, the second electronic circuit 22 and the communication module 21 are enclosed in a capsule 26 for protection against the intrusion of dust and / or liquids.

[0057] The capsule, which can be designed according to international standards and / or norms relating to sealing (e.g.: IP 45, IP 55 or 65), makes it possible to protect these circuits against intrusion of dust and / or liquids. According to the invention, the meter is installed on an external wall of the spindle housing ( Figure 3 ).

[0058] The capsule may be attached to the spindle housing through fastening means, such as screws, nails, screw-nut arrangements, clips, a layer 30 of magnetic and / or adhesive material.

[0059] The capsule of Figures 2 and 3 further comprises one or more accelerometers 240 arranged to sense vibrations affecting the housing 10 as well as one or more thermal sensors arranged to sense a temperature of the housing.

[0060] The 20 meter of the figure 2 further comprises an inductive circuit or a magnetic field sensor positioned on a surface of the power supply and / or the spindle motor so as to sense their electromagnetic fields.

[0061] The 20 meter of the figure 3further comprises an inductive circuit in the form of a ring positioned around the spindle power cable 13 so as to capture the electromagnetic field generated by the electric current delivered to the spindle motor.

[0062] Advantageously, the capsule can also contain the first electronic circuit, in particular in the form of a vibration sensor 240, an inductive circuit or a magnetic field sensor 242 and / or a thermal sensor 241. The capsule can also contain the electrical power source 25 for powering the counter 20. This arrangement makes it possible to make the counter autonomous with respect to the spindle, which facilitates its installation on spindles of various manufacturing types as well as an update of a spindle on the market.

[0063] The power source comprises a rechargeable battery or accumulator and may be configured to be recharged during operation of the spindle and / or by means of a connector and / or without wires.

[0064] The counter may include a visual operating status indicator 27, for example housed on or in a wall of the capsule, arranged to provide a visual indication to an operator.

[0065] The visual indication may be a function of: operating time, wear condition, abnormal operating condition, number of work cycles and / or number of machined parts.

[0066] Reading spindle information can be done using a wireless reader, i.e. a scanner. Once the data is on the scanner, it can be sent to a central computer (e.g. a server) for spindle management purposes. The scanner allows a user (e.g. a machining technician) to collect data from each spindle as needed. The information on the spindles can then be transferred wirelessly, either directly or through the scanner, to a server running spindle management software.

[0067] There figure 4 graphically illustrates the management of spindle 1 by means of a scanner 80 and / or a server 90 for managing machining spindles.

[0068] The scanner 80 and / or server 90 comprise a communication module making it possible to receive data concerning the spindle which have been collected and / or determined by the counter (or delivered by its first electronic circuit) which equips it, through a wireless communication interface compatible with that of the spindle counter (for example through a device or module communicating according to the Bluetooth, ANT, Wi-Fi, LoRa and / or RFID communication standard).

[0069] Optionally, the communication module is configured to transmit the signal and / or command to pin 1, so as to trigger in the counter a transmission of one or a distinct subgroup of data.

[0070] This data includes in particular: operating time, wear status, abnormal operating status, number of working cycles and / or number of parts machined by spindle 1.

[0071] The data may, additionally or alternatively, concern data saved during the manufacture, revision or repair of the spindle, in particular: the numerical identity of the spindle, the serial number, the indication of the spindle manufacturer; the indication of the spindle type; the indication of the maximum number of revolutions of the spindle; the indication of the power, electrical intensity and / or voltage for use of the spindle; the indication of the machine on which the spindle is used; the indication of the position of the spindle on the machine; and / or a history of commissioning, handling and revision of the spindle.

[0072] These technical, operational and / or machining data allow a workshop manager to determine the operational readiness of the spindle as well as its handling plan, overhaul, and possibly its replacement, without having to resort to systems for annotating working hours for each spindle based on manual annotations or feelings from machining technicians, sheets or tables of machining parts and / or measurement operations on spindle components.

[0073] This technical, operational and / or machining data allows a machining technician, equipped with the scanner 80, to obtain data relating to the spindle, in particular without having to consult the spindle operating instructions and the machining tables relating to the spindle, in particular for the purpose of choosing a spindle for a particular machining operation, and of determining and / or checking the settings of a machine supporting the spindle.

[0074] There Figure 5graphically illustrates an example of management of all the machining spindles 1 of a workshop (i.e. a spindle park 1) by means of a scanner 80 and a server 90.

[0075] Advantageously, the server 90 is equipped with software allowing overall management of the spindle park with status indicator based on data delivered by the counter equipping each spindle and / or raw data delivered by the first electronic circuit of the counter.

[0076] Advantageously, the server is configured through software to determine, from signals provided by said first electronic circuit 24 and / or the operating time of each pin 1: the number of working cycles and / or a number of parts machined using the spindle; and / or the state of wear of the spindle 1, in particular of the machining tool 12, of the electric motor 11 and / or of one or more bearings 16 (in particular of the bearings of the bearing(s)); and / or the abnormal operating state of the spindle, in particular of the machining tool 12, of the electric motor 11 and / or of one or more bearings 16 (in particular of the bearings of the bearing(s), this as an alternative or in addition to the second electronic circuit 22 of pin 1.

[0077] This allows complete management of the spindle fleet and in particular predictive maintenance allowing planning of preventive spindle changes.

[0078] Through the software, a vibration signature for each type of spindle will be determined, and thresholds for vibration signatures and / or maximum temperatures for the bearings are set. Based on these thresholds, the data collected by the scanner and / or the server provides an overview of the condition of each spindle in the fleet in terms of quality and wear. These parameters can be determined by learning and / or by testing on a measuring bench.

[0079] The server, through this software, is thus configured to indicate the status of each pin by a color code, which can be the following: green color: when both the vibrations of the spindle, in particular of one of its components such as the bearings, and the temperatures are within acceptable standards and do not require intervention; orange color: the vibrations of the spindle (in particular of one of its components such as the bearings), and / or the temperatures of the spindle (in particular of one of its components such as the bearings) are within standards (i.e. within a range of values) which would require a change of the spindle. The quality of the machining may be affected. An intervention must be planned; red color: The spindle no longer meets the standards allowing sufficient quality and reliability to be ensured. The spindle may fail at any time or is already stopped. This scenario will require an unplanned emergency intervention and a shutdown of the production machine.

[0080] Thus, the decision to replace a spindle depends on different predetermined thresholds in the server, including thresholds for vibration signatures and / or temperature maxima

[0081] The value of these thresholds may depend on the type and model of pin; some pins need to be replaced more frequently than others.

[0082] The value of these thresholds may also, or alternatively, depend on user choice. Some users who require high accuracy and / or very high reliability may, for example, choose more restrictive thresholds.

[0083] The server may also include a self-learning module, for example a neural network-based module receiving as input identifications of spindle type, number of hours of use, vibration and / or temperature parameters, and trained using failure information or tolerance measurements, in order to automatically determine the thresholds.

[0084] Advantageously, the server, through the software, allows the entry of additional technical or management data concerning each spindle in the fleet, in particular an indication of: the overhaul company(ies), the overhaul duration, the duration of intervention on the machine for spindle change, the price of the spindle, the overhaul price, the overhaul value (taper, face, with or without pinnule), the force of the clamping device, the type of spindle taper, the runout of the control pinnule, and / or the number of warranty hours (new and after overhaul).

[0085] This data may also include an indication of: maximum permissible temperatures on the bearings (internal and / or external temperature probe), vibration signature (threshold: green, orange, red) and / or the number of pins in stock available for exchange.

[0086] Advantageously, the server is configured, through the software, to establish and update a plan for handling, servicing and replacing each spindle in the fleet based on the data received from the counter of each spindle and this additional data.

[0087] Advantageously, the server is configured, through the software, to display through a user interface: the list of all the spindles, an indication of the actual operating hours of each spindle and / or the spindle park, an indication of the spindles under or out of warranty depending on the number of hours on the counter, the predictive threshold depending on the sensor data or the number of hours (green - orange - red), an alarm for threshold change (temperature - vibrations).

[0088] In addition, this solution allows management not only of machining spindles in operation or ready for machining, but also of machining spindles which are stored in one or more storage locations in the workshop awaiting use. Reference numbers used in the figures

[0089] 1 motorized spindle 10 housing 101 outer surface of the housing 102 inner surface of the housing 11 electric motor 111 rotor 112 stator 12 machining tool 13 power cable 14 power supply 15 shaft 16 bearing 20 running time counter 21 transceiver 22 data processing unit 23 data storage memory 24 electronic circuit to determine a rotation state of the motor; 240 accelerometer 241 temperature sensor 242 Hall effect sensor 25 battery 26 protective cap 27 LED 30 adhesive layer 60 machining set 80 portable reading scanner 90 server

Claims

1. Spindle (1) for machining, comprising: a housing (10) enclosing an electric motor (11) rotatably driving a machining tool (12), said machining tool being rotatably mounted relative to the housing by means of at least one bearing (16), preferably a roller bearing; an electronic operating time counter (20) comprising: a first electronic circuit (24, 240, 241, 242) arranged to determine a rotation state of the motor (11) and / or the machining tool (12); a second electronic circuit (22) configured to count the operating time of the spindle from signals supplied by said first electronic circuit (24); and a communication module (21) arranged to transmit said operating time through a communication interface, preferably wireless; an electrical power supply (25) comprising a rechargeable battery (25) or an accumulator; the first electronic circuit comprising an inductive circuit or a magnetic field sensor, preferably a Hall effect sensor, arranged to detect a magnetic and / or electromagnetic field of the electric motor (11) and / or of a power supply (13, 14) of the motor; characterized in that the second electronic circuit (22), the communication module (21) and the electrical power supply (25) are enclosed in a protection capsule (26) against an intrusion of dust and / or liquids; and in that said protection capsule (26) is fixed to an external surface of said housing (10) of the spindle (1), preferably by means of magnetic and / or adhesive fasteners (30).

2. Spindle according to claim 1, said rechargeable battery (25) or said accumulator being configured to be recharged during operation of the spindle and / or by means of a connector and / or wirelessly.

3. Spindle according to one of claims 1 to 2, the inductive circuit (242) being in the form of a ring positioned around a cable (13) supplying power to said electric motor (11) of the spindle and configured to detect the electromagnetic field generated by the electric current supplied to the spindle motor.

4. Spindle according to one of claims 1 to 3, the first electronic circuit (24, 240, 241) of said counter (20) being enclosed in the protection capsule (26); said counter (20) being preferably enclosed in the protection capsule (26).

5. Spindle according to one of claims 1 to 4, the first electronic circuit comprising: a vibration sensor, preferably comprising one or more accelerometers, arranged to detect vibrations affecting the housing (10), said at least one bearing (16), the electric motor (11) and / or the machining tool; and / or a thermal sensor, preferably comprising one or more temperature sensors, arranged to detect a temperature of the housing (10), said at least one bearing (16), the electric motor (11) and / or the machining tool.

6. Spindle according to one of claims 1 to 5, said second electronic circuit being configured to determine a machining force, a machining torque, a work load, a number of work cycles and / or a number of machined parts using the spindle from signals supplied by said first electronic circuit (24).

7. Spindle according to one of claims 1 to 6, said second electronic circuit being configured to determine: a wear condition of the spindle or one of its components, in particular the machining tool (12), the electric motor (11) and / or said at least one bearing (16); and / or an abnormal operating condition of the spindle or one of its components, in particular the machining tool (12), the electric motor (11) and / or the at least one bearing (16), based on the operating time of the spindle counted by the second electronic circuit (22) and / or signals provided by the first electronic circuit (24).

8. Spindle according to one of claims 1 to 7, the counter (20) comprising a data storage memory (23); said communication module (21) being arranged to transmit data stored in said memory; said data comprising said operating time, said wear condition, said abnormal operating condition, said number of work cycles, and / or said number of machined parts.

9. Spindle according to claim 8, said data further comprising: a numerical identity of the spindle, a serial number, an indication of the manufacturer of the spindle, an indication of the type of spindle, an indication of the maximum number of revolutions of the spindle, an indication of the power, electrical intensity and / or voltage for use of the spindle, an indication of the machine on which the spindle is used, an indication of the position of the spindle on the machine, and / or a history of the commissioning of the spindle.

10. Spindle according to one of claims 1 to 9, the spindle and / or the counter (20) comprising a visual operating status indicator (27) providing a visual indication, the visual indication being a function of: said operating time, said wear condition, said abnormal operating condition, said number of work cycles, and / or said number of machined parts.

11. Spindle according to one of claims 1 to 10, said wireless communication interface being a device or module configured to exchange data according to a Bluetooth, ANT, Wi-Fi, LoRa and / or RFID communication standard.

12. Machining set (60), comprising: at least one machining spindle (1) according to one of claims 1 to 11, and a machining spindle management device (80, 90) arranged to receive, via a preferably wireless communication interface: said operating time, said wear condition, said abnormal operating condition, said number of work cycles and / or said number of machined parts of said at least one machining spindle (1).

13. Machining set (60) according to claim 12, comprising: a server configured to determine a status indicator for each spindle of said at least one machining spindle based on the operating time of the spindle and / or signals provided by said first electronic circuit (24) of the spindle; said status indicator being determined from among at least two distinct status indicators, one of said at least two status indicators indicating a normal state of the spindle, and the other of said at least two status indicators indicating a state of the spindle requiring its overhaul and / or replacement.