Method and apparatus for optimizing wire electrical discharge machining

Abstract

A method of electro-erosion machining, carried out on an electro-erosion machine using an electro-erosion wire, the electro-erosion wire being packaged on a reel, the reel being provided with an identification data medium (11) storing embedded identification data (ME) relating to the electro-erosion wire and embedded control data (CE) associated with the embedded identification data (ME) by a control function (F), specific optimized machining parameters (PSP) and the control function (F) being previously stored in the electro-erosion machine; the electro-erosion machine receiving from the identification data medium (11) read control data (CL) and read identification data (ML); the electro-erosion machine seeking to determine whether the read identification data (ML) and the read control data (CL) are associated by the control function (F); in and only in the case where the read identification data (ML) and the read control data (CL) are associated by the control function (F), the electro-erosion machine initiating or authorizing a machining operation as a function of the functioning of the specific optimized machining parameters (PSP).

Description

Technical Field

[0001] This invention relates to electrical discharge machining (EDM) equipment in which a small-diameter continuous metal wire is taken from a spool and passed through a machining zone filled with a suitable dielectric in an EDM machine. In this machining zone, a portion of the wire is held near a workpiece by a guide, the workpiece being conductive. A current generator is connected between the wire and the workpiece, generating an electric arc between them. This arc causes ablation of both the wire and the workpiece. To compensate for the ablation, the workpiece undergoes permanent displacement in its longitudinal direction within the machining zone. As ablation occurs on the workpiece, the wire is gradually displaced towards the workpiece by the EDM machine, thereby creating a material removal notch on the workpiece. Background Technology

[0002] The performance characteristics of machining via electrical discharge machining depend on many parameters, especially: - The processing parameters, determined by the electrical discharge machining (EDM) machine, may include the electrical power provided by the current generator, the longitudinal displacement rate of the wire, the longitudinal mechanical tension applied to the wire in the processing zone, the agitation of the dielectric in the processing zone, and the functional offset between the wire and the workpiece (more generally, simply referred to as "offset"). - Parameters relating to the structure or quality of the wire itself may include the shape of the wire, its length, its origin, the stress it has experienced since it was manufactured, the electrical power that the wire can withstand during processing without breaking, the structure and composition of the wire itself, the mechanical tension that the wire can withstand without breaking, and the mechanical properties of the wire that make it easier or more difficult to introduce the wire into the machining area and its guide of the EDM machine at the start of processing. - Parameters relating to the structure or quality of a workpiece may include the shape of the workpiece, its structure, and its composition.

[0003] Based on these parameters, material removal from a workpiece may be faster or slower, characterized by processing speed or the rate at which the wire penetrates the workpiece.

[0004] Based on these parameters, the machining process can be more or less precise, characterized by the accuracy of the cuts produced on the workpiece.

[0005] Alternatively, based on these parameters, the machining process can be characterized by the surface finish of the resulting workpiece cross-section.

[0006] Typically, during the machining of workpieces with a specific type of electrical discharge machining (EDM) wire, the user is guided by the machine to select the appropriate machining parameters used by the EDM machine in order to obtain one or more specific machining performance characteristics. The set of machining parameters is determined by the EDM machine manufacturer and is used for various machining conditions. Expert users can, in principle, select appropriate machining parameters or modify the machining parameters suggested by the machine to improve the level of machining performance.

[0007] However, in order to truly optimize the specific machining performance characteristics obtained by machining wire with a specific type of electrical discharge machining, it seems necessary to first conduct a large number of machining experiments by changing the machining parameters, machining targets, and workpieces to obtain a specific optimized set of machining parameters. This constitutes the first challenge.

[0008] Then, if the same specific set of optimization parameters is used, but the EDM wire is used under these conditions with only minor differences, experience shows that the obtained machining results are disappointing and far from optimized. This constitutes the second problem.

[0009] As a result, in order to obtain true optimization of specific machining performance characteristics, the EDM machine must correlate optimized machining parameters with the EDM wire, wherein the optimized machining parameters are specific to the EDM wire and are the result of optimization after a large number of prior tests.

[0010] Therefore, on the one hand, the EDM machine needs to know accurately and without error the type of EDM wire loaded by the user for processing, and on the other hand, it also needs to include stored data of a specific set of optimized processing parameters for that type of EDM wire.

[0011] When the user imports identification data about the EDM wire and the selected machining parameters into the EDM machine, errors may occur, especially due to incorrect input or incorrect reading, which cannot guarantee that optimized machining results will be obtained.

[0012] Document WO 2017 / 056045 A1 proposes an automatic importation of identification data of EDM wire into an EDM machine. To this end, the EDM wire is packaged on a spool, which itself includes a radio tag capable of communicating with a data reader associated with the EDM machine, typically at a frequency of 13.56 MHz. The EDM machine can then adjust its machining parameters by taking into account the identification data derived from the radio tag.

[0013] However, experience shows that electrical discharge machining (EDM) machines generate electromagnetic interference, which can hinder the correct reading of identification data on radio tags. The 13.56 MHz frequency can be disrupted by certain EDM generators of EDM machines using the wire or nearby EDM machines, resulting in read and / or write errors despite the use of communication protocols.

[0014] In fact, data transmission protocols can detect errors between the transmitter and the EDM machine. However, they cannot detect whether erroneous identification data has been previously written. For example, such errors may include erroneous writes due to errors in the EDM machine's own software during previous use of the reel, which is quite common. Another example is write errors that occur during processing before the reel is mounted onto the EDM machine (storing, retrieving, weighing, etc.).

[0015] It should be understood that incorrect reading of identification data related to EDM wire, or the presence of incorrect identification data, can lead to EDM wire breakage or disappointing machining results by applying inappropriate machining parameters. Summary of the Invention

[0016] One problem addressed by this invention is how to avoid the drawbacks of known electrical discharge machining (EDM) methods and equipment, and in particular how to avoid identification errors related to the EDM wire loaded on the EDM machine for machining tasks.

[0017] Another problem addressed by this invention is how to ensure the most satisfactory machining results when using an electrical discharge machining (EDM) machine to process wire. The aim is to limit the consequences of potential write or read errors, that is, to achieve optimal machining results regardless of whether the wire reel has been accurately identified.

[0018] Another objective of this invention is to ensure that a particular type of wire is used in conjunction with a particular technology, and vice versa, in order to obtain standardized processing results.

[0019] Therefore, the present invention aims to automatically ensure that optimal processing results can be obtained as long as a specific type of electrical discharge machining wire (i.e., wire with a specific structure and / or characteristics) can be definitively associated with processing parameters specific to that electrical discharge machining wire and for which optimization results have been given in previous tests.

[0020] Preferably, the purpose of this invention is to take into account historical data of electrical discharge machining wire usage when necessary, in order to optimize machining with determinism.

[0021] Furthermore, another aspect of the present invention aims to automatically ensure that, when the electrical discharge machining wire cannot be definitively associated with specific machining parameters for which optimization results have been given in previous extensive trials, quality degradation is minimized during machining operations.

[0022] To achieve these and other objectives, according to a first aspect, the present invention proposes an electrical discharge machining (EDM) method, performed on an EDM machine using EDM wire packaged on a spool, the spool being associated with and forming an assembly with an identification data medium in the form of an RFID radio tag data carrier, the identification data medium storing embedded identification data in digital form related to the EDM wire, wherein... (a) The electrical discharge machining machine receives the read identification data from the identification data medium, the read identification data representing the embedded identification data contained in the identification data medium; (b) The electrical discharge machining machine adjusts the machining parameters for machining by taking into special consideration the identification data read from the identification data medium from the reel; And among them: - The specific optimized machining parameters were determined by machining tests previously conducted using the same type of EDM wire packaged on a reel, for example by conducting the tests using different machining parameters, and selecting those parameters that provided the best machining performance in the tests as the specific optimized machining parameters; - The specific optimized machining parameters and control functions were previously stored in the storage device of the electrical discharge machining machine; - The embedded control data was previously identified as being associated with the embedded identification data of the electrical discharge machining wire via a control function and was stored on the identification data medium; Before step (b): - The electrical discharge machining (EDM) machine receives and reads control data from the identification data medium; - Electrical discharge machining (EDM) machines seek to determine whether the read identification data and read control data are correlated through a control function; - The EDM machine initiates or authorizes machining operations based on the specific optimized machining parameters only when the read identification data and read control data are associated through the control function.

[0023] In this application, the term "associated" means that the reel and the identification data medium are arranged in a manner that allows them to be used together by an electrical discharge machining (EDM) machine, thereby forming an assembly. The user uses the reel to place it on the EDM machine and uses the identification data medium to enable the EDM machine to read it. For example, the reel and the identification data medium can be packaged together: the identification data medium can be fixed (e.g., glued) to the flange of the reel, or fixed to a bag containing the reel, or fixed or placed in a container containing the reel.

[0024] In RFID tags, as in computer or EDM machine controllers, information such as numerical values, text data, and mathematical functions is stored digitally, typically as a two-digit code, and stored in a specific location. Therefore, each piece of information or data can be interpreted as an integer ME. In this application, the term "control function F" refers to any mathematical calculation that can be applied to the integer ME to uniquely generate another integer CE, which is then used as control data.

[0025] Preferably, the electrical discharge machining method further includes: - The standard machining parameters were determined by previous machining tests using various electrical discharge machining wires, for example by using different machining parameters, and those parameters that provided satisfactory machining performance for the various electrical discharge machining wires on average during the tests were selected as the standard machining parameters. - The standard machining parameters were previously stored in the storage device of the electrical discharge machining machine; If the EDM machine determines that the read identification data and the read control data are not associated through the control function, then the EDM machine initiates or authorizes a machining operation based on the standard machining parameters.

[0026] In all cases, providing the following functionality may be advantageous: - When determining the embedded control data, the control function is applied to the embedded identification data related to the electrical discharge machining wire; - After receiving the read control data, the EDM machine applies the control function to the read identification data to derive the verification data, and the EDM machine compares the read control data received from the identification data medium with the verification data; If the verification data matches the read control data, then the EDM machine determines that the read identification data and the read control data are associated through the control function.

[0027] Alternatively, it may be advantageous to provide the following functionality: - When determining the embedded control data, the control function is applied to the embedded identification data related to the electrical discharge machining wire; - After receiving the read control data, the EDM machine applies the inverse function of the control function to the read control data to derive the verification data, and the EDM machine compares the read identification data received from the identification data medium with the verification data; If the verification data matches the read identification data, then the EDM machine determines that the read identification data and the read control data are associated through the control function.

[0028] The control function can advantageously be an encryption function for the encrypted private key.

[0029] The identification data medium is a radio tag, which stores embedded identification data and embedded control data in digital form, and can also record usage history data of EDM wire collected during previous use sequences of wire packaged on a reel.

[0030] According to a second aspect, the present invention provides an electrical discharge machining (EDM) machine suitable for carrying out the above-described processing method, wherein: - The electrical discharge machining machine and the data reading device together form a functional unit. The data reading device can read the embedded identification data stored in the form of an identification data medium in digital form of an RFID radio tag. The identification data medium and the reel together form an assembly. The wire is packaged on the reel, and the data reading device can send the read identification data to the electrical discharge machining machine. - The data reading device is also able to read embedded control data stored by the identification data medium of the reel and send the read control data to the electrical discharge machining machine; - Electrical discharge machining includes a storage device containing specific optimized machining parameters and control functions; - The electrical discharge machining machine includes an electrical discharge machining wire identification device, which includes a computing device and a stored computer program including an identification sequence. The identification sequence is capable of verifying whether the read identification data and the read control data are associated through the control function. - The electrical discharge machining (EDM) machine includes a control device and a stored computer program containing control sequences that can initiate or authorize machining operations based on specific optimized machining parameters, and only if read identification data is associated with read control data via a control function.

[0031] According to a third aspect, the present invention provides a wire reel for an electrical discharge machining (EDM) machine, suitable for implementing the above-described processing method. The reel is associated with and forms an assembly with an identification data medium in the form of an RFID radio tag. The data in the identification data medium can be read by a data reading device associated with the EDM machine. The identification data medium stores embedded identification data related to the wire, and also stores embedded control data. The embedded control data and the embedded identification data are associated through a control function. The control function is a mathematical calculation that can be applied to the embedded identification data, which is treated as an integer, thereby uniquely generating the embedded control data.

[0032] Preferably, in the identification data medium, the control function is an encryption function for the encrypted private key.

[0033] The identification data medium is a radio tag, which stores embedded identification data and embedded control data in digital form, and can also record usage history data of EDM wire collected during previous use sequences of wire packaged on a reel.

[0034] According to a fourth aspect, the present invention provides an apparatus suitable for performing an electrical discharge machining (EDM) method. This apparatus includes: - Electrical discharge machining (EDM) machine; - Electrical discharge machining wire packaged on a reel; - Identification data media in the form of RFID radio tags, associated with a reel and forming an assembly together, and accessible to read the data they contain; - The embedded identification data of the wire is stored in the identification data medium; - A data reading device, forming a functional unit together with the electrical discharge machining (EDM) machine, is capable of reading embedded identification data stored on an identification data medium on a reel and sending the read identification data to the EDM machine. in: - Embedded control data is also stored on the identification data medium; - The data reading device can also read embedded control data stored by the identification data medium of the reel and send the read control data to the electrical discharge machining machine; - The electrical discharge machining machine includes a storage device storing control functions and specific optimized machining parameters, which are determined by previous machining tests using electrical discharge wire of the same type as that packaged on a reel, for example by conducting the tests using different machining parameters and selecting those parameters that provide the best machining performance in the tests as the specific optimized machining parameters; - The electrical discharge machining machine includes an electrical discharge machining wire identification device, which includes a computing device and a stored computer program including an identification sequence. The identification sequence is capable of verifying whether the read identification data and the read control data are associated through the control function. - The electrical discharge machining (EDM) machine includes a control device and a stored computer program containing control sequences that can initiate or authorize machining operations based on specific optimized machining parameters, and only if read identification data is associated with read control data via a control function.

[0035] Preferably, the electrical discharge machining equipment has the following characteristics: - The standard machining parameters were determined in advance by machining tests using various electrical discharge machining wires, for example by using different machining parameters, and those parameters that provided satisfactory machining performance for the various electrical discharge machining wires on average during the tests were selected as standard machining parameters, and the standard machining parameters were also stored in the storage device of the electrical discharge machining machine. - If the read identification data and the read control data are not associated through the control function, then the control sequence of the EDM machine is initiated or authorized to perform machining operations according to the standard machining parameters.

[0036] In this electrical discharge machining equipment, the identification data medium is a radio tag, which stores embedded identification data and embedded control data in digital form. The data reading device is a radio frequency communication device capable of communicating with the radio tag. Attached Figure Description

[0037] Other objects, features, and advantages of the present invention will be described in conjunction with the appendix. Figure 1 As shown in the following description of the specific embodiments given, wherein: [ Figure 1 ] Figure 1 This is a schematic diagram of an electrical discharge machining (EDM) machine according to an embodiment of the present invention processing a workpiece by means of wire packaged on a spool; [ Figure 2 ] Figure 2 An identification data medium of the passive radio tag type according to a first embodiment of the present invention is illustrated schematically. The passive identification data medium communicates with a data reading device via a radio frequency, which is associated with or implemented in an electrical discharge machining (EDM) machine. [ Figure 3 ] Figure 3An active or semi-active radio tag type identification data medium according to a second embodiment of the present invention is illustrated, which communicates with a data reading device via a radio frequency, the data reading device being associated with or implemented in an electrical discharge machining (EDM) machine.

[0038] Preferred Specific Implementation First consideration Figure 1 An electrical discharge machining (EDM) apparatus according to an embodiment of the present invention is illustrated. The machining apparatus generally includes an EDM machine 1, in which a machining zone 2 filled with a suitable liquid dielectric is provided. The shape and structure of the machining zone 2 are designed to receive and hold a workpiece 3. An EDM wire 4, packaged on a reel 5, is removed from the reel 5 and passes over a guide 6 of the EDM machine 1, which holds the EDM wire 4 in place and drives it longitudinally at a suitable rolling speed, as indicated by arrow 7. The EDM wire 4 passes through the machining zone 2, in which it is held near the workpiece 3 according to a suitable functional offset.

[0039] The electrical discharge machining machine 1 also includes a current generator 8 connected between the electrical discharge machining wire 4 and the workpiece 3 to generate an electric arc between the electrical discharge machining wire 4 and the workpiece 3.

[0040] During operation, the electric arc causes ablation of the electrical discharge machining (EDM) wire 4 and the workpiece 3. The permanent longitudinal rolling 7 of the EDM wire 4 within the machining zone 2 prevents breakage of the wire 4 due to ablation caused by the electric arc on the wire. However, the ablation caused by the electric arc on the workpiece 3 constitutes material removal, which can create a cut 10 on the workpiece 3 through gradual relative displacement of the EDM wire 4 toward the workpiece 3 (e.g., as indicated by arrow 9). In the processing zone 2, the electrical discharge machining wire 4 must be kept taut by the longitudinal mechanical traction force provided by the guide 6 in order to maintain a straight shape and a stable and defined geometric position, which ensures that the cut 10 formed on the workpiece 3 has a good geometry.

[0041] At the start of machining, the free end of the electrical discharge machining (EDM) wire 4 must be introduced into the guide 6 and then into the machining area 2. Typically, the EDM machine 1 includes an operational sequence that ensures automatic wire introduction. However, this requires the EDM wire 4 to have satisfactory straightness and stiffness characteristics to ensure the introduction of the free end of the EDM wire 4 even when the guide 6 holds the wire only in the middle portion away from the free end.

[0042] Electronic control circuit 17 drives the moving parts of electrical discharge machining 1 to set processing parameters, such as the electrical power provided by current generator 8, the rate of longitudinal displacement 7 of wire, the longitudinal mechanical tension applied to the wire in processing zone 2, the agitation of the dielectric in processing zone 2, and the functional offset between wire 4 and workpiece 3.

[0043] According to the present invention, the processing equipment further includes an identification device that can automatically identify the electrical discharge machining wire 4 packaged on the reel 5, and an optimization control device that is adapted to authorize or activate the drive of the functional components of the electrical discharge machining machine 1 depending on the identified electrical discharge machining wire 4, so as to perform optimized processing operations on the workpiece 3 through the electrical discharge machining wire 4.

[0044] exist Figures 1 to 3 In the embodiment shown, the identification device specifically includes an identification data medium 11 fixed on the flange of the spool 5. The identification data medium 11 stores embedded identification data ME related to the electrical discharge machining wire 4 on the one hand, and embedded control data CE on the other hand. The embedded control data and the embedded identification data ME are associated through a control function F, as will be explained below.

[0045] The identification data medium 11 collaborates with the data reading device 13 via a wireless link 100. The data reading device 13 is functionally associated with the electrical discharge machining machine 1. The wireless link 100 allows communication between the identification data medium 11 and the data reading device 13.

[0046] Figure 2 and Figure 3 Two embodiments of the identification device according to the present invention are illustrated by example.

[0047] exist Figure 2 In this design, the identification data medium 11 is a passive radio tag, including an antenna 11a and a power supply circuit 11b. The power supply circuit 11b is capable of acquiring a portion of the electrical energy picked up by the antenna 11a to generate a power supply voltage, which powers the other electronic circuits of the radio tag. An electronic processing circuit 11c receives an electronic request signal 14c picked up by the antenna 11a, communicates with a storage circuit 11d containing embedded identification data ME and embedded control data CE, and generates an electronic response signal 14d depending on the electronic request signal 14c. The electronic response signal 14d is then transmitted by the antenna 11a. For example, upon receiving an electronic request signal 14c requesting communication of identification information, the passive radio tag 11 returns a response signal 14d containing the embedded identification data ME and the embedded control data CE.

[0048] In this configuration, the data reading device 13 is an active device, a radio frequency transmitter capable of remotely activating the radio tag 11. It includes an antenna 13d and electronic circuitry 13e, which generates a request signal 14c transmitted from the antenna 13d to the radio tag 11 and processes a response signal 14d received from the radio tag 11 and picked up by the antenna 13d. The wireless link 100 is a radio link.

[0049] Exemplary embodiments of radio tags and data reading devices are described in document US4,724,427.

[0050] exist Figure 3 In this context, the identification data medium 11 is an active or semi-active radio tag, and the identification data medium 11 also contains... Figure 2 The main components of the embodiment are specifically: antenna 11a, power supply circuit 11b, electronic processing circuit 11c, and storage circuit 11d, which have the same characteristics as... Figure 2 The components in the embodiments have the same function. Figure 3 In addition, the identification data medium 11 also includes an embedded power source 15, which can provide power to the electronic processing circuit 11c and the storage circuit 11d in place of the power picked up by the antenna 11a or in addition to the power picked up by the antenna 11a.

[0051] In this case, the identification data medium 11 also includes embedded sensors, for example, four embedded sensors 16a, 16b, 16c, and 16d respectively provide signals to the electronic processing circuit 11c. These signals are image signals of the acceleration experienced by the spool 5 carrying the wire 4 and the identification data medium 11, image signals of the ambient temperature, image signals of the ambient relative humidity, and image signals of the weight of the spool 5.

[0052] The electronic processing circuit 11c is driven by an embedded computer program that includes a storage sequence for scanning signals generated by embedded sensors 16a, 16b, 16c and 16d and storing them in the storage circuit 11d.

[0053] exist Figure 3 In this embodiment, the data reading device 13 is also an active device that transmits radio frequencies and can remotely activate the radio tag 11 when necessary. The data reading device 13 includes an antenna 13d and electronic circuitry 13e. The electronic circuitry 13e is used to generate a request signal 14c to be sent to the radio tag 11 and to process the received signal 14d from the radio tag 11 and picked up by the antenna 13d. The wireless link 100 is a radio link.

[0054] The control circuit 17 of the electrical discharge machining machine 1 includes a computing device 17a (such as a processor) and a storage device 17b.

[0055] The storage device 17b of the control circuit 17 contains multiple sets of processing parameters, each set of which is preferably intended for a specific type of machining performed using a specific type of electrical discharge machining (EDM) wire. Specifically, the storage device 17b of the control circuit 17 contains one or more sets of specific optimized processing parameters (PSPs), each set of which is determined after prior machining tests performed on the same type of EDM machine 1 using the same type of EDM wire M. In the storage device 17b of the control circuit 17, the specific optimized processing parameter PSP sets are wholly or partially associated with identification data related to the corresponding EDM wire M.

[0056] The storage device 17b of the control circuit 17 also includes a computer program P, which is implemented by the computing device 17a. The computer program P mainly drives the moving parts of the electrical discharge machining machine 1 to perform machining operations on the workpiece 3 according to the selected set of machining parameters.

[0057] The computer program P of the control circuit 17 of the electrical discharge machining (EDM) machine 1 includes at least one download sequence for downloading embedded identification data ME and embedded control data CE stored in the identification data medium 11. As is well known in computer technology, the download sequence is programmed to identify the identification data and control data by the address of a specific storage location of the data in the RFID radio tag. The download sequence drives the data reading device 13 to generate a request signal 14c and sends the request signal 14c to the identification data medium 11, which then returns information 14d to the data reading device 13. The information 14d received by the data reading device 13, after experiencing any possible electromagnetic interference, arrives at the control circuit 17 in the form of read identification data ML and read control data CL.

[0058] The computer program P of the control circuit 17 of the electrical discharge machining (EDM) machine 1 includes at least one adjustment sequence for adjusting machining parameters. This adjustment takes into account the identification data ML and control data CL read from the identification data medium 11 on the reel 5. Thus, the device according to the invention can automatically adjust the EDM parameters in the EDM machine 1 depending on the specific properties of the EDM wire 4 used. For example, the adjustment sequence can modify or limit parameters such as the mechanical tension of the EDM wire 4 in the machining zone 2, the current intensity flowing through the EDM wire 4 in the machining zone 2, the rate of longitudinal displacement 7 of the EDM wire 4 in the machining zone 2, the agitation of the dielectric in the machining zone 2, the lateral displacement 9 of the EDM wire 4 in the machining zone 2, and the parameters maintaining a functional offset between the EDM wire 4 and the workpiece 3.

[0059] If the identification data medium 11 contains all the necessary data, the data related to the EDM wire 4 can be downloaded directly by simply querying the identification data medium 11.

[0060] Alternatively, the download of data related to the electrical discharge machining wire 4 can be partially indirect. In this case, the download sequence includes at least downloading the identity of the wire 4 manufacturer and the serial number of the reel 5 by querying the identification data medium 11, and an instruction sequence for automatically downloading data related to the reel 5 of the wire 4 from the manufacturer's computer server by querying the manufacturer's computer server via the Internet, using the information of the identity of the wire 4 manufacturer and the serial number of the reel 5.

[0061] According to the present invention, the computer program P of the control circuit 17 of the electrical discharge machining machine 1 includes a specific sequence for identifying the electrical discharge machining wire 4, which is identified more rigorously not only by taking into account the identification data ML read from the identification data medium 11, but also by taking into account the previously mentioned control function F and by taking into account the control data CL read from the identification data medium 11.

[0062] The control function F is neither stored as plaintext nor interpreted within the information stored in the identification data medium 11. Instead, the supplier of the EDM wire 4 packaged on the reel 5 uses the control function F to generate embedded control data CE from the embedded identification data ME. Thus, the embedded identification data ME and the embedded control data CE are associated through the control function F.

[0063] In contrast, the control function F itself is stored in the storage device 17b provided in the control circuit 17 of the electrical discharge machine 1.

[0064] On the identification data medium 11, the embedded identification data ME can be stored, in particular, in the form of a series of binary signals (0 or 1), i.e., in the form of natural integers based on base 2. According to a first particularly simple example presented for ease of understanding the invention, the control function F can be composed of a NOT function that inverts each bit of the binary signal of the embedded identification data ME: the binary 0 signal of the embedded identification data ME becomes a binary 1 signal in the embedded control data CE, and the binary 1 signal of the embedded identification data ME becomes a binary 0 signal in the embedded control data CE.

[0065] According to the second, more complex example, the control function F can give the remainder C of the Euclidean division of the embedded identification data ME by the integer K, which itself constitutes the private encryption key.

[0066] For example, the key K can be chosen as 19. By applying the function F to the embedded identification data ME with a value of 99, the resulting embedded control data CE will have a value of 4, since 99 = 19 × 5 + 4.

[0067] According to the third example, on the identification data medium 11, the embedded identification data ME can be encoded as a string according to the computer standard of ASCII encoding. The control function F can be an encryption function called "aes-128-cbc", which uses a private encryption key K, which itself can be encoded according to the computer standard of ASCII encoding. The use of this function can be easily implemented by computing it on the website https: / / encode-decode.com / aes-128-cbc-encrypt-online.

[0068] For example, the key K can be selected as "Thermocompact". By applying this encryption function F to the embedded identification data ME of the "Fil ThermoSA 900 N / mm2 0.25mm produit le 13 / 08 / 2020 sous le numéro 123456789" series, the following embedded control data CE can be obtained: "mUcNi+tUBbdONTrx8TmY76nBrtaqx5Cf1RZKdMbVMjf+POZK+aHmLFqE09FufsQC0bGC89bG9D5pUdb7DY+euaftyLyZQJrExo5GOKGuDcI=".

[0069] Upon receiving the read identification data ML and the read control data CL, the electrical discharge machining wire 4 identification sequence can apply the control function F to the read identification data ML to generate verification data V, and can compare the verification data V with the read control data CL. If they match, the identification sequence considers that the read identification data ML and the read control data CL are associated through the control function F, thus knowing that the read identification data ML matches the embedded identification data ME, and therefore knows that the embedded identification data is correct.

[0070] Alternatively, upon receiving the read identification data ML and the read control data CL, the electrical discharge machining wire 4 identification sequence can convert the inverse function F of the control function F. -1 The control data CL is applied to generate verification data W, which can be compared with the identification data ML received from the identification data medium 11. If they match, the identification sequence considers that the read identification data ML and the read control data CL are associated through the control function F, thus knowing that the read identification data ML matches the embedded identification data ME, and therefore knowing that the embedded identification data is correct.

[0071] One advantage of using the control function F based on private key encryption is that it significantly reduces the risk of errors in EDM wire identification. In fact, in the third example above, if an error has been introduced into the embedded identification data ME, or if transmission interference introduces a slight modification between the embedded identification data ME and the read identification data ML, the verification data V will be significantly different from the read control data CL, facilitating identification. In this particular case, if the sequence “SA” of the embedded identification data ME is modified to the sequence “SB” in the read identification data ML (only replacing the letter “A” with the letter “B”), then the verification data V is “u3hROePgvtGCCG3Ji2XFKyRElPfJSB6ZnF23gn7KrK4NqOD7WuH8t9QargS1dAiOG52mCHcoqPACtkE3vcHXspFJ8f3uP5aKTUnKGaFZeXg=”. V and CL are completely different. Therefore, when the verification data V matches the embedded control data CE, specific optimized machining parameters PSP can be applied with confidence.

[0072] According to the present invention, the computer program P of the control circuit 17 of the electrical discharge machining machine 1 further includes a specific authorization sequence. According to the specific authorization sequence, if the authorization conditions are met, the electrical discharge machining machine 1 authorizes or initiates the processing operation of the electrical discharge machining wire 4 using specific optimized processing parameters PSP.

[0073] According to the first authorization condition, the identification sequence needs to consider matching the read identification data ML with the embedded identification data ME.

[0074] According to the second authorization condition, the read identification data ML must correspond to the basic identification data of one of the electrical discharge machining wire types M recorded line by line in the storage device 17b set in the control circuit 17 of the electrical discharge machining machine 1.

[0075] When the first and second authorization conditions are met, a specific authorization sequence authorizes or initiates the processing operation of the electrical discharge machining wire 4 using the specific optimized processing parameters PSP previously stored in the storage device 17b set in the control circuit 17.

[0076] The above control methods ensure accurate identification of the electrical discharge machining wire 4. Therefore, users can be certain that as long as the electrical discharge machining machine 1 is automatically started or authorized for optimized machining, optimized machining results can be obtained.

[0077] Another advantage is that when the EDM machine tool 1 automatically assigns another set of machining parameters for the given EDM wire 4, the machining results are not too bad. In fact, it has been found that using standard machining parameters yields better machining results than using a specific optimized machining parameter PSP on an EDM wire 4 that is not provided for that specific optimized machining parameter PSP.

[0078] For example, for the aforementioned wire "SA", a variable functional offset can be successfully used in finishing using an optimized parameter set, while for wire "SB", a fixed offset, i.e., using a standard machining parameter set, can yield better finishing results.

[0079] This is clearly evident in the measurement results below: - By using wire "SA" and the specific optimized machining parameters PSP for that wire "SA", a surface roughness Ra of 0.16 micrometers is obtained in the wire direction and a surface roughness of 0.17 micrometers is obtained in the cutting direction, so the workpiece is considered qualified; - By using wire "SB" and the same specific optimized machining parameters PSP as those for wire "SA", the roughness Ra obtained in the wire direction is 0.17 micrometers, while the roughness obtained in the cutting direction is 0.20 micrometers. Therefore, the workpiece is considered unqualified. - By using wire "SA" and standard machining parameters, a surface roughness Ra of 0.19 micrometers is obtained in the wire direction and a surface roughness of 0.20 micrometers is obtained in the cutting direction, therefore the workpiece is considered acceptable; - By using wire "SB" and standard machining parameters, a surface roughness Ra of 0.20 micrometers is obtained in the wire direction and a surface roughness of 0.21 micrometers is obtained in the cutting direction, therefore the workpiece is considered acceptable.

[0080] In other words, if wire "SB" is used and the same specific optimized machining parameters PSP as those for wire "SA" are used, the roughness Ra obtained in the cutting direction is significantly higher than the roughness Ra obtained in the wire direction. This roughness Ra difference is visible to the naked eye and is considered unacceptable.

[0081] Conversely, if wire "SB" and standard machining parameters are used, the average roughness Ra is slightly larger, but the roughness Ra in the cutting direction is close to the roughness Ra in the wire direction, so the workpiece is visually considered acceptable.

[0082] Therefore, in the absence of certainty regarding the identification result of the electrical discharge machining wire 4, it is preferable to use the standard machining parameter set PST.

[0083] Therefore, according to an advantageous embodiment, the storage device 17b of the control circuit 17 further includes one or more standard machining parameter sets PST, each of which is determined after prior machining tests using the same type of electrical discharge machining machine 1 with the aim of obtaining a satisfactory average machining quality by using several types of electrical discharge machining wire M.

[0084] In this case, when at least one of the first and second authorization conditions is not met, a specific authorization sequence authorizes or initiates the machining operation of the EDM wire 4 using the standard machining parameters PST previously stored in the storage device 17b set in the control circuit 17. Thus, although the machining operation performed according to the standard machining parameters PST automatically selected by the EDM machine 1 is not optimal, it is still optimized, meaning that the machining quality can be degraded as little as possible.

[0085] Furthermore, considering that the machining results obtained by applying specific optimized machining parameters PSP to EDM wire 4 of a type different from the commonly provided type are often worse than those obtained by applying standard machining parameters PST, according to an advantageous embodiment, the present invention provides a function for restricting or prohibiting the reading and copying of specific optimized machining parameters PSP files stored in the storage device 17b of the EDM machine 1. For this purpose, the computer program P may include an access control sequence that controls access to the specific optimized machining parameters PSP, which may, for example, require the input of one or more passwords. This avoids the situation where a user attempts to manually force the use of specific optimized machining parameters PSP in the hope of obtaining optimized machining results using EDM wire 4 that is not provided for that specific optimized machining parameters PSP, ultimately resulting in inferior and defective machining results.

[0086] This invention is not limited to the embodiments explicitly described, but includes various variant and generalized embodiments, all of which fall within the protection scope of the following claims.

Claims

1. An electrical discharge machining (EDM) method, performed on an EDM machine (1) using an EDM wire (4), the EDM wire (4) being packaged on a spool (5), the spool (5) forming an assembly together with an identification data medium (11) in the form of an RFID radio tag data carrier, wherein the identification data medium (11) stores embedded identification data (ME) related to the EDM wire (4) in digital form at a specific location, wherein (a) The electrical discharge machining (1) receives read identification data (ML) from the identification data medium (11), the read identification data (ML) representing embedded identification data (ME) contained in the identification data medium (11). (b) The electrical discharge machining (1) adjusts the machining parameters for machining by taking into special consideration the read identification data (ML) from the identification data medium (11) on the reel; Its features are: - The specific optimized processing parameters (PSP) were determined by previous processing tests using the same type of EDM wire (4) packaged on the reel (5); - The specific optimized machining parameters (PSP) and control functions (F) were previously stored in a specific location in the storage device (17b) of the electrical discharge machine (1); - The standard machining parameters (PST) were determined through previous machining experiments using various electrical discharge machining wires; - The standard machining parameters (PST) were previously stored in a specific location in the storage device (17b) of the electrical discharge machine (1); - Embedded control data (CE) was previously determined to be associated with the embedded identification data (ME) of the electrical discharge machining wire via the control function (F) and was stored at a specific location on the identification data medium (11); And prior to step (b): - The electrical discharge machining (1) receives control data (CL) read from the identification data medium (11); - The electrical discharge machining (1) seeks to determine whether the read identification data (ML) and the read control data (CL) are associated through the control function (F); - The electrical discharge machine (1) initiates or authorizes a machining operation based on the specific optimized machining parameters (PSP) only when the read identification data (ML) and the read control data (CL) are associated through the control function (F); If the electrical discharge machine (1) determines that the read identification data (ML) and the read control data (CL) are not associated through the control function (F), then the electrical discharge machine (1) initiates or authorizes a machining operation based on the standard machining parameters (PST).

2. The electrical discharge machining method according to claim 1, characterized in that: - When determining the embedded control data (CE), the control function (F) is applied to the embedded identification data (ME) related to the electrical discharge machining wire (4); - After receiving the read control data (CL), the electrical discharge machine (1) applies the control function (F) to the read identification data (ML) to derive the verification data (V) from it, and the electrical discharge machine (1) compares the read control data (CL) received from the identification data medium (11) with the verification data (V); - If the verification data (V) matches the read control data (CL), then the electrical discharge machining (1) determines that the read identification data (ML) and the read control data (CL) are associated through the control function (F).

3. The electrical discharge machining method according to claim 1, characterized in that: - When determining the embedded control data (CE), the control function (F) is applied to the embedded identification data (ME) related to the electrical discharge machining wire (4); - After receiving the read control data (CL), the electrical discharge machining (1) will output the inverse function (F) of the control function (F). -1 The control data (CL) read is applied to derive verification data (W) from it, and the electrical discharge machining (1) compares the read identification data (ML) received from the identification data medium (11) with the verification data (W); - If the verification data (W) matches the read identification data (ML), then the electrical discharge machining (1) determines that the read identification data (ML) and the read control data (CL) are associated through the control function (F).

4. The electrical discharge machining method according to any one of claims 1 to 3, characterized in that, The control function (F) is the encryption function (K) for the encrypted private key.

5. An electrical discharge machining (EDM) machine (1) for carrying out the method according to any one of claims 1 to 4, wherein: - The electrical discharge machining (1) and the data reading device (13) together form a functional unit. The data reading device (13) is capable of reading embedded identification data (ME) at a specific location in an identification data medium (11) in the form of an RFID radio tag, which is stored in digital form. The identification data medium (11) and the reel (5) together form an assembly. The electrical discharge machining wire (4) is packaged on the reel (5). The data reading device (13) is capable of sending the read identification data (ML) to the electrical discharge machining (1). - The data reading device (13) is also able to read embedded control data (CE) at a specific location stored in the identification data medium (11) on the reel (5), and can send the read control data (CL) to the electrical discharge machining machine (1). - The electrical discharge machining (1) includes a storage device (17b) in which specific optimized machining parameters (PSP) and control functions (F) are stored at specific locations. - The electrical discharge machining machine (1) includes an electrical discharge machining wire identification device, which includes a computing device (17a) and a stored computer program (P) including an identification sequence, the identification sequence being able to verify whether the read identification data (ML) and the read control data (CL) are associated through the control function (F). - The electrical discharge machining (1) includes a control device (17) and a stored computer program (P) including a control sequence, which is capable of initiating or authorizing machining operations based on the specific optimized machining parameters (PSP) only when the read identification data (ML) and the read control data (CL) are associated through the control function (F).

6. A spool (5) for electrical discharge machining (EDM) wire (4) for implementing the EDM method according to any one of claims 1 to 4, forming an assembly together with an identification data medium (11) in the form of an RFID radio tag, the data of which can be read by a data reading device (13), the data reading device (13) forming a functional unit together with the EDM machine (1), the identification data medium (11) storing embedded identification data (ME) related to the EDM wire (4) at a specific location; Its features are, The identification data medium (11) also stores embedded control data (CE) in a specific location, which is associated with the embedded identification data (ME) through a control function (F).

7. The spool (5) for electrical discharge machining (4) according to claim 6, characterized in that, The control function (F) is the encryption function (K) for the encrypted private key.

8. The spool (5) for electrical discharge machining (4) according to claim 6, characterized in that, The identification data medium (11) is fixed on the flange of the spool (5), or fixed on the bag containing the spool (5), or fixed or placed in the container containing the spool (5).

9. An electrical discharge machining (EDM) apparatus for carrying out the method according to any one of claims 1 to 4, comprising: - Electrical discharge machining (1); - Electrical discharge machining wire (4) packaged on a reel (5); - An identification data medium (11) in the form of an RFID radio tag, which forms an assembly with the reel (5) and can be accessed to read the data stored therein; - The embedded identification data (ME) of the wire is stored in a specific location by the identification data medium (11); - The data reading device (13), together with the electrical discharge machining (1), forms a functional unit, capable of reading the embedded identification data (ME) stored in the identification data medium (11) of the reel (5), and capable of sending the read identification data (ML) to the electrical discharge machining (1). Its features are, - Embedded control data (CE) is also stored in a specific location on the identification data medium (11); - The data reading device (13) is also able to read the embedded control data (CE) stored in the identification data medium (11) of the reel (5), and can send the read control data (CL) to the electrical discharge machining machine (1). - The electrical discharge machining (1) includes a storage device (17b) in which a control function (F) and a specific optimized machining parameter (PSP) are stored at a specific location. The specific optimized machining parameter (PSP) is determined by a machining test previously conducted using electrical discharge machining wire of the same type as that packaged on the reel (5). - The standard machining parameters (PST) were determined by previous machining tests using various electrical discharge machining wires and are also stored in a specific location in the storage device (17b) of the electrical discharge machining machine (1); - The electrical discharge machining machine (1) includes an electrical discharge machining wire identification device, which includes a computing device (17a) and a stored computer program (P) including an identification sequence, the identification sequence being able to verify whether the read identification data (ML) and the read control data (CL) are associated through the control function (F). - The electrical discharge machining (1) includes a control device (17) and a stored computer program (P) including a control sequence, which is capable of initiating or authorizing machining operations based on the specific optimized machining parameters (PSP) only when the read identification data (ML) and the read control data (CL) are associated through the control function (F). - If the read identification data (ML) and the read control data (CL) are not associated through the control function (F), then the control sequence of the electrical discharge machining (1) initiates or authorizes a machining operation according to the standard machining parameters (PST).

10. The electrical discharge machining equipment according to claim 9, characterized in that, The control function (F) is the encryption function (K) for the encrypted private key.

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