Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
  • B23H7/02—Wire-cutting
  • B23H7/08—Wire electrodes
  • B23H7/10—Supporting, winding or electrical connection of wire-electrode
  • B23H7/101—Supply of working media
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H1/00—Electrical discharge machining, i.e. removing metal with a series of rapidly recurring electrical discharges between an electrode and a workpiece in the presence of a fluid dielectric
  • B23H1/02—Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges
  • B23H1/028—Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges for multiple gap machining
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H11/00—Auxiliary apparatus or details, not otherwise provided for
  • B23H11/003—Mounting of workpieces, e.g. working-tables
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
  • B23H9/14—Making holes

Definitions

• TITLE Electroerosion machining device for a plurality of bars
• the present invention relates to an electroerosion machining device.
• machining electrode consists of a taut wire.
• the machining electrode consists of a taut wire.
• several bars to be machined are held in such a way that their axes are parallel and coplanar, in a plane parallel to the straight line defined by the machining electrode.
• Such an electroerosion device thus makes it possible to carry out the precise machining of numerous bars simultaneously, which allows the production of parts such as, for example, dental instruments.
• the simultaneous machining of a plurality of bars which is conventionally carried out in a bath of dielectric liquid, such as deionized water, generates the emission of numerous particles, chips and impurities in this liquid, having the effect of polluting it.
• This pollution of the liquid has the effect of causing it to gradually lose its dielectric properties.
• it also has the effect of generating fouling of all the mechanical components of the machining device which are in contact with this dielectric liquid. This fouling can cause mechanical blockages or false electrical contacts affecting the reliability of the device.
• Dielectric liquid filtration equipment is generally provided to limit the pollution of this liquid. However, such equipment is most often inefficient when the machining device is used intensively, with a plurality of simultaneous machining operations.
• the present invention aims in particular to overcome at least some of these drawbacks of the prior art.
• the invention particularly aims to allow an improvement in the reliability of the machining device by electroerosion.
• the invention according to at least some of its embodiments, has the particular objective of avoiding, to a large extent, the pollution of the dielectric liquid in which the electroerosion machining is carried out.
• the invention also aims to facilitate the performance of identical machining on the bars which are machined together.
• Another object of the invention is to make it possible to obtain bars machined with great precision.
• an electroerosion machining device comprising a substantially linear electrode, and at least one support of bars able to hold a plurality of bars to be machined, substantially coplanar and parallel, and to approach them together to the electrode, in a dielectric liquid.
• the device comprises suction equipment suitable for sucking up the dielectric liquid, the suction equipment comprising at least one suction mouth associated with each of the contact points between one of the bars and the electrode, capable of sucking up the dielectric liquid surrounding this point of contact.
• each of the suction vents has a main opening, in the longitudinal axis of the bar with which it is associated.
• the main opening has a section whose surface is greater than 10 times the surface of the section of the bar with which it is associated.
• each of the suction mouths is shaped to receive an end portion of the bar with which it is associated.
• the bars are cylindrical in shape, and each of the suction mouths has a substantially cylindrical shape, with an inside diameter greater than 3 times the diameter of the bar with which it is associated.
• each of the suction mouths has a side opening forming a slot extending along a wall of the suction mouth, from the main opening, in a direction parallel to the longitudinal axis of the bar with which it is associated.
• each of the suction mouths comprises a bar centering guide with which it is associated in the main opening.
• each of the suction mouths is placed, during machining, at a distance of less than 10 mm from the point of contact with which it is associated.
• each of the suction mouths is placed, during machining, at a distance of less than 3 mm from the point of contact with which it is associated.
• the suction mouths of the suction equipment are mounted on a collector capable of receiving the liquid sucked up by the suction mouths.
• an electroerosion machining device which comprises a substantially linear electrode, and at least one bar support able to maintain a plurality of bars to be machined, substantially coplanar and parallel, and to approach them together to the electrode.
• this device comprises a plurality of main sockets, each of the main sockets being able to pivot relative to the bar support, around a pivot axis, the pivot axes of the different main sockets being substantially coplanar and parallel, each of the main sleeves having a hole for holding a bar, extending along an axis parallel and distinct from the pivot axis of the main sleeve.
• the bar support has a plurality of cylindrical bores, the axes of which are substantially coplanar and parallel, each of the main sleeves having a cylindrical portion introduced into one of the cylindrical bores.
• each of the main sleeves has a shoulder resting against a surface of the bar support on which the bores open.
• each of the shoulders has graduations capable of identifying its angular position relative to the bar support.
• this machining device comprises a locking means capable of pressing each of the shoulders against the surface.
• the locking means comprises a flange, carried by the bar support, capable of pressing on the shoulder, in a direction parallel to the pivot axis.
• the bar support has at least one holding plate, remote from the main sleeves, carrying a secondary sleeve capable of pivoting relative to the holding plate around the pivot axis of one of the main sleeves, each of the secondary sockets having a hole for holding a bar, extending along an axis parallel and distinct from the pivot axis.
• the characteristics of this particular embodiment, concerning the pivoting bushings making it possible to adjust the position of the bars relative to the bar support can be implemented in combination with the characteristics concerning the equipment suction device suitable for sucking up the dielectric liquid or independently of these characteristics concerning the suction equipment, for example in an electroerosion machining device comprising suction equipment of a different type, or even in a device for EDM machining not including suction equipment.
• FIG. 1 is a schematic representation of a electrical discharge machining device.
• Figure 2 is a detail view of part of a bar support implemented in the machining device of Figure 1.
• Figure 3 is a schematic representation of an electroerosion machining device comprising a suction equipment according to one embodiment of the invention.
• FIG. 4 is a detail view showing part of the electroerosion machining device of FIG. 3.
• FIG. 5 is a detail view of an electroerosion machining device comprising suction equipment according to a another embodiment of the invention.
• FIG. 1 is a schematic representation of a electrical discharge machining device.
• Figure 3 is a schematic representation of an electroerosion machining device comprising a suction equipment according to one embodiment of the invention.
• FIG. 4 is a detail view showing part of the electroerosion machining device of FIG. 3.
• FIG. 5 is a detail view of an electroerosion machining device comprising suction equipment according to a another embodiment of the invention.
• FIG. 1 is a schematic
• FIG. 6 is a detail view of part of a bar support implemented in an electroerosion machining device according to a particular embodiment.
• Figure 7 shows a main sleeve that can be implemented in the bar support of Figure 6.
• Figure 8 is a sectional view of a main sleeve that can be implemented in the bar support of Figure 6.
• Figure 9 is a sectional view of a secondary sleeve that can be implemented in the bar support of Figure 6.
• FIG. 1 is a schematic representation of an electroerosion machining device 1, intended to machine bars 3, on which the improvements of the present invention can be implemented.
• This machining device 1 comprises a frame 12, which carries a lower electrode support 121 and an upper electrode support 122.
• delivery means (not shown) make it possible to circulate the electrode 11 between the nozzles 112 and 111, for example by progressively delivering the wire constituting the electrode 11 through the upper nozzle 112 and gradually pulling this wire through the lower nozzle 111. This progressive delivery of the electrode 11 ensures that the portion of the electrode 11 performing the electroerosion is always in an optimal state.
• the electroerosion machining device 1 also comprises a tank (not shown in Figure 1) filled with a dielectric liquid, for example demineralized water, in which the bars to be machined 3 and the electrode 11 are submerged, at least in part.
• a dielectric liquid for example demineralized water
• the contact points between the bars to be machined 3 and the electrode 11 are immersed in this dielectric liquid.
• spraying means it is also possible for spraying means to project the dielectric liquid at the contact points between the bars to be machined 3 and the electrode 11, so that these contact points are surrounded by the dielectric liquid. without being immersed in it.
• the electroerosion machining device 1 also comprises electrical circuits (not shown) capable of subjecting the electrode 11 and the bars to be machined 3 to different electrical potentials.
• electrical circuits capable of subjecting the electrode 11 and the bars to be machined 3 to different electrical potentials.
• the electroerosion machining device 1 also comprises a device for holding the bars to be machined, able to hold the bars to be machined 3 and to move them relative to the electrode 11, so as to allow them to be machined by electroerosion .
• this displacement is a relative displacement: according to the embodiments, it is possible that the bars to be machined 3 move relative to the electrode 11, or that the electrode 11 moves relative to the bars to be machined. machine 3. a. Bar support
• this bar holding device comprises two bar supports 21 and 22, each carrying a plurality of bars 3 to be machined.
• the bars 3 are held substantially parallel to each other, and substantially in the same plane, which is substantially parallel to the electrode 11.
• the bars shown in the figures have circular sections. They may however, in other embodiments, have sections of different shape.
• Each of the supports 21 and 22 is movable relative to the electrode 11, so as to be able to simultaneously approach the electrode 11 all the bars 3 that it carries. When all of these bars 3, carried by one of the bar supports 21 and 22, are sufficiently close to the electrode 11, electric discharges can occur so as to machine, in an identical manner, all of the bars 3 carried by the bar support 21 or 22.
• rotation drive means (not shown in FIG. 1) make it possible to rotate simultaneously, around their longitudinal axes, all the bars 3 carried by one of the bar supports 21, 22. These bars can thus be, at the same time, machined over their entire periphery.
• the two bar supports 21 and 22 are advantageously movable, independently of each other, relative to the electrode 11. They can thus approach the bars they carry to the electrode 11 so that these bars are machined, either simultaneously or alternately. To avoid collisions between these bar supports 21 and 22 or the bars 3 that they carry, the bars 3 carried by the bar support 22 are positioned at offset heights with respect to the bars 3 carried by the bar support 21. Thus, all of the bars 3 carried by the supports 21 and 22 can be in contact with, or close to, the electrode 11, the bars 3 carried by the support 21 alternating, along the electrode 11, with the bars 3 carried by the support 22.
• the bars 3 carried by the bar support 21 are placed in a plane substantially perpendicular to the bars 3 carried by the bar support 22.
• the bar supports 21 and 22 can be placed in planes forming, with each other, an angle of between 90° and 180°. When this angle is 180°, the supports 21 and 22 face each other, on either side of the electrode 11.
• FIG. 2 is a detail view of the bar support 21, showing one of the bars 3 held in position by the bar support 21.
• This bar 3 has a cylindrical shape, centered around a longitudinal axis 30 As shown in this figure, this bar 3 is held in position, at least in part, by the engagement of this bar in a hole 210 formed in the bar support 21.
• the hole 210 has, over at least part of its length , dimensions just greater than that of the bar 3, allowing this bar 3 to slide in the hole 210.
• This hole 210 opens onto the front face 211 of the bar support 21 which is, by convention, the face of the bar support 21 which faces electrode 11, when the electrode machines bar 3.
• a portion to be machined 31 of the bar 3 engaged in this hole 210 protrudes on this front face 211, so as to be able to be machined by the electrode 11.
• This portion to be machined 31 ends with the free end 310 of the bar 3.
• the hole 210 is through, so that a reserve portion 32 of the bar 3 to be machined protrudes from the bar support 21, on its rear face, opposite to its face. before 211.
• the hole 210 holds the portion 31 to be machined in position, so that this portion can only perform a sliding movement along its longitudinal axis 30 and, when the bar 3 has a cylindrical shape as in the example represented, a rotation around its longitudinal axis 30.
• These bar drive means may for example be incorporated into the bar support 21 or be placed behind the bar support 21, so as to act on the reserve portion 32 of the bar 3. c. Support bracket
• a holding bracket 212 To prevent the portion of the bar 3 which is machined by the electrode from undergoing a deflection detrimental to the precision of the machining, there is provided in the embodiment shown a holding bracket 212.
• This holding bracket 212 comprises a support pin 2121, extending substantially parallel to the longitudinal direction of the bar 3, and carrying a retaining plate 2122 in which is defined a retaining hole 2123 in which the free end of the bar 3. To facilitate the introduction of this free end into the holding hole 2123, this hole can advantageously have a chamfer on its edge facing the bar support 21.
• the bar support 21 can be produced without a holding bracket.
• FIG. 3 shows an electroerosion machining device 1 equipped with suction equipment 6.
• This suction equipment 6 comprises a collection pipe 60 which carries a plurality of suction mouths 61, which are immersed in a bath of dielectric liquid in which the spark erosion takes place.
• the collection pipe 60 is connected to a pumping device (not shown) making it possible to drive the liquid contained in this collection pipe 60 towards filtration equipment (not shown).
• This pumping device therefore causes suction, via the suction mouths 61, of the liquid in which these suction mouths 61 are immersed.
• the machining device 1 allows the simultaneous machining of five bars 3, carried by a bar support 21.
• this bar support 21 does not include a holding bracket ends of the bars 3 which must be machined.
• the suction equipment 6 has a suction mouth 61 for each of the bars 3 to be machined simultaneously.
• the collector, or collection line 60 extends between the lower electrode support 121 and the upper electrode support 122, these suction mouths 61 are fixed relative to the frame 12 of the machining device 1.
• Each of the suction mouths 61 is advantageously placed close to the point of contact between the electrode 11 and a bar 3, when this bar 3 is machined.
• suction mouths 61 are shown in more detail in Figure 4. These suction mouths 61 have a generally tubular shape, of annular section. They therefore have a main opening 611 at their end. In a way advantageously, this main opening is located in the immediate vicinity of the point of contact between the bar 3 which is associated with it and the electrode 11. It is thus located, preferably, at a distance less than 10 mm from the point of contact between the electrode 11 and bar 3. It is even more preferable for this distance to be as small as possible, for example less than 3 mm.
• each suction mouth 61 extends in the extension of the longitudinal axis of the bar 3.
• the opening of this suction mouth 61 is placed in such a way that the bar 3 can, during its machining, be introduced into the suction mouth 61.
• the surface of the section of the opening of the suction mouth 61 is at least ten times greater than the surface of the section of the bar 3.
• the bar 3 and the suction mouth 61 have cylindrical shapes, the internal diameter of the suction mouth is at least three times greater than the diameter of the bar 3.
• This positioning of the suction mouth 61 advantageously makes it possible to carry out a suction of the dielectric liquid in the immediate vicinity of the machining, which constitutes the source of pollution of this liquid.
• the suction equipment 6 can thus take a small quantity of dielectric liquid, which concentrates all or almost all of the pollution and chips generated by the machining.
• the particular position of the suction mouth 61, the opening of which is placed in alignment with the bar 3 which is machined, also generates a current of sucked liquid which moves substantially parallel to the longitudinal axis of the bar 3 , towards the free end of this bar 3.
• Such a current advantageously makes it possible to facilitate the suction of chips which can wrap around the bar 3 during machining.
• the suction mouths 61 also have a side opening 612.
• This side opening 612 is like a slot extending along a wall of the suction mouth 61, from the main opening 611, in a direction parallel to the longitudinal axis of the suction mouth 61.
• This side opening 612 advantageously has dimensions allowing the bar 3, when it is introduced into the suction mouth 61, to out of this suction mouth 61 in a direction perpendicular to its longitudinal direction.
• all of the suction mouths 61 carried by the suction equipment 6 have identical side openings, in order to allow the bar support 21, which holds the set of bars 3, to perform a relative movement, with respect to the suction equipment 6, in a direction perpendicular to the longitudinal direction of its bars 3, when the bars 3 are inserted into the suction mouths 61.
• the dimensions of the main openings 611 and of the side openings 612 are chosen so that the presence of the side openings 612 does not cause excessive loss of suction at the level of the main opening 611. b. Suction in the gallows
• Figure 5 shows a portion of a machining device comprising suction equipment according to another embodiment of the invention. More specifically, this embodiment relates to a machining device 1 whose bar supports 21 are equipped with brackets 212, as represented by FIGS. 1 and 2.
• FIG. 5 is a detail view of one of these brackets 212, comprising a support finger 2121 carrying a retaining plate 2122. This figure also shows a portion of a suction pipe 550, one end of which is linked to the retaining plate 2122.
• This suction pipe 550 is advantageously connected to a pumping device, which sends the liquid contained in this suction pipe 550 to filtration equipment.
• the support plate 2122 of the bracket 212 has a suction grid which forms the end of the suction pipe 550.
• This suction grid 55 has openings 551, passing through the support plate 2122.
• This grid suction 55 also has the holding hole 2123 of the bracket 212, intended to receive the bar 3.
• This holding hole 2123 is advantageously placed in the center of the suction grid 55, surrounded by the suction openings 551.
• the suction openings 551 and the retaining hole 2123 together constitute openings allowing the suction of impurities and chips generated by machining. This suction is done in the direction of the longitudinal axis of the bar 3.
• a portion not shown of the suction pipe 550 can advantageously extend along the finger 2121 of the stem 212 to join a collection pipe (not shown) s' extending along the bar support 21, able to collect the polluted liquids sucked up at all the brackets 212 associated with each of the bars 3.
• FIG. 6 shows a portion of a bar support 21 according to a particular embodiment.
• each element identical or similar to those shown in Figure 2 is designated by the same reference.
• each hole 210 passing through the bar support 21 is replaced by a cylindrical bore 411.
• the axes of the various bores 411 are advantageously coplanar and parallel to each other.
• Each of the bores 411 is intended to receive a sleeve 42, called the main sleeve.
• one bore 411 is shown with a sleeve 42, and another bore 411 is shown without a sleeve.
• a sleeve 42 is shown in Figure 7 and, in sectional view, in Figure 8.
• the outer surface of the sleeve 42 has a cylindrical portion 421, centered on an axis 423 and of diameter substantially equal to the diameters of the bores 411, which is intended to be introduced into one of these bores.
• the sleeve 42 also has a hole, which is the hole 210 allowing the passage of the bars 3 through the bar support 21.
• This hole 210 is drilled through the sleeve 42 along an axis 2100, parallel to but distinct from the axis 423 of the cylindrical portion 421 of the sleeve 42.
• the hole 210 in which a bar 3 can be inserted, extends along an axis 2100 parallel but distinct from the axis 423 of the bore 411.
• the sleeve also has a shoulder 422, of cylindrical shape, of larger diameter than the diameter of the bores 411.
• This shoulder 422 aims to prevent the sleeve 42 from being inserted entirely into a bore 411. It is intended to bear against the front face 211 of the bar support 21, when the sleeve 42 is introduced into a bore 411 and can be manipulated by an operator to rotate the sleeve 42, in the bore 411, around the axis 423. This rotation of the sleeve 42 has the effect of modifying the position of the axis 2100 of the hole 210, with respect to the bore 411.
• the shoulder 422 preferably has graduations 424 or marks making it possible to know the angular position of the sleeve 42, relative to a corresponding mark (not shown) of the front face 211 of the bar support 21. A user can thus easily act on this shoulder 422 to turn the sleeve 42 and place it in the angular position that he wishes. According to this angular position, he will be able to offset, very precisely, the axis of the hole 210 with respect to the plane defined by the axes of the bores 411.
• a correspondence table can be defined to allow the operator to know precisely the value of this offset, for each graduation 424 of the shoulder 422 of the sleeve 42.
• the distance between the axis 423 of the cylindrical portion 421 of the sleeve 42 and the axis 2100 of the hole 210 can be chosen according to the need to offset the bars 3 to be machined. However, it is advantageous for this value to be low, for example of the order of two or three hundredths of a millimeter.
• the variation in the angular position of the sleeve 42 then makes it easy to obtain a small but very precise offset of the bar 3 carried by the sleeve, relative to the plane defined by the axes of the bores 411.
• the hole 210 is offset in much greater proportions, in order to make this offset visible in the figures.
• a flange 43 tightened by a screw against the front face 211 of the bar support 21 makes it possible to press the sleeve 42 in order to press its shoulder against the face front 211 of the bar support 21.
• Figure 8 shows a main sleeve 42 in section view, along a plane passing through the axis.
• the sleeve 42 can advantageously be made of electrically insulating material, for example plastic material, if it is necessary to prevent the passage of electric current between the bar to be machined 3 and the bar support 21.
• this sleeve can be made of ceramic or, to obtain greater homogeneity of its internal diameter over the entire length of the hole 210, of carbide.
• the openings of the hole 210 are preferably chamfered to facilitate the introduction of the bar 3 therein.
• each stem 212 itself has a cylindrical bore 412, passing through the retaining plate 2122, in place of the retaining hole 2123.
• Each of the bores 412 is preferably aligned with a bore 411.
• the retaining hole 2123 has the same offset relative to the cylindrical portion 4221 of the secondary sleeve 44, as the hole 210 relative to the cylindrical portion 421 of the main sleeve 42.
• the shoulder 4222 of the secondary sleeve 44 is also graduated, which allows it to be placed in the same angular position as the sleeve 42.
• Flanges 43 allow, by tightening the shoulder 4222 against the retaining plate 2122, to block the sleeve 44 in the desired position.
• the secondary sleeve 44 may have a shorter length than the main sleeve 42.
• the bar support 21 may be implemented without gallows 212.
• the characteristics represented in the present application for the bar support 21 can be implemented in the same way in another bar support equipping the same machining device, for example the bar support 22, if this device machining has more than one bar support.
• the characteristics of this particular embodiment, concerning the pivoting bushings making it possible to adjust the position of the bars relative to the bar support can be implemented in combination with the characteristics concerning the equipment suction device suitable for sucking up the dielectric liquid or independently of these characteristics concerning the suction equipment, for example in an electroerosion machining device comprising suction equipment of a different type, or even in a device for EDM machining not including suction equipment.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

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• 2021
  • 2021-11-16 WO PCT/FR2021/000135 patent/WO2022106762A1/fr unknown
  • 2021-11-16 EP EP21820658.9A patent/EP4247581A1/de not_active Withdrawn

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