FR2494155A1 - ELECTRO-EROSION MACHINING ELECTRODE AND METHOD FOR CARRYING OUT THE SAME - Google Patents

Abstract

THE INVENTION PROVIDES A CIRCULATING WIRE ELECTRO-EROSION MACHINING ELECTRODE. THE ELECTRODE ACCORDING TO THE INVENTION CONSISTS OF AN ELONGATED ELEMENT HAVING A THICKNESS BETWEEN 0.05 AND 0.5MM, PRESENTING A RUGGED PERIPHERAL SURFACE OVER AN EXTENT OF THIS SURFACE, THIS SURFACE IS PROVIDED WITH PROJECTIONS AND REINFORCEMENTS THEREIN. COMPLIANT FOLLOWING A PREDETERMINED UNIFORM PATTERN, THESE PROJECTIONS AND INDUSTRIES HAVING A SIZE BETWEEN ONE FIFTIETH AND ONE THIRD OF THE THICKNESS OF THE EXTENDED ELEMENT. SUCH AN ELECTRODE HAS A GREAT CAPACITY OF EMISSION OF HEAT.

Description

Electrode-machining electrode and its process

implementation.

  The invention relates to a circulating wire machining electrode and to an electro-erosion machining process

  of a conductive part of electricity by means of this filament

circulating electrode.

  The terms "electro-erosion machining" and "electro-erosion" used herein are intended to refer to the machining process

  in general, including electrical discharge machining

  in which material is removed from the room by the action of successive electric discharges, the electrochemical machining in which the workpiece is machined by

  electrolytic solution of the material, and the electro-

  chemical discharge system in which the removal of material is provided by combined actions of electric discharges

  and electrolytic solution of the metal.

  In the wireline electro-erosion process, a wire

  continuous electrode is transported axially from supply means to recovery means by means of

  axial drive means of the wire. On the way of traffic

  tion of the wire, a pair of machining guide elements may be placed on either side of a conductive part

  electricity, to extend or draw linearly the

  electrode moving between them, so that the wire passes through the workpiece, thus placing the wire electrode in precise machining relationship with the workpiece. A machining electric current, typically or preferably in the form of a succession of time-spaced electrical pulses, is applied between the circulating wire electrode and the workpiece, through a machining gap immersed in a liquid machining, for example a water-based liquid of dielectric nature or low conductivity, or an aqueous solution of an electrolyte,

  to electro-erode the material from the workpiece.

  While material removal is taking place, the workpiece is moved transversely to the longitudinal axis of the straight-line path of the circulating wire electrode, along a predetermined two-dimensional machining advance path, advantageously under numerical control, as such manner that

  the desired machining contour is provided in the workpiece.

  It is important that the electrode wire has a good conductivity

  as well as a composition providing a high speed

  satisfactory removal of material and prone to little wear by erosion. It is desirable for the wire electrode to be heat resistant and to maintain sufficient tensile strength at the high temperature produced by the passage of a high density or high density machining stream.

  current, and so it does not break in operation.

  Usually, the wire electrode is constituted as a single wire having a diameter of between 0.05 and 0.5 mim,

  metal based on copper or copper alloy, such as brass.

  Such a yarn is provided by stretching through a die and naturally has a circular cross-section as well as a

smooth peripheral surface.

  The machining liquid is provided, typically by one or more

  nozzles, in the machining interval, to act as an interval agent while driving the discharge current

  and / or electrolyte and, on the other hand, coolant

  to dissipate the heat produced by the current flow

  machining having the high intensity or current density re-

  quise. A higher intensity or current density is desirable to obtain a higher material removal rate and better efficiency, and this requires the renewal of the machining liquid in the interval to

higher speed.

  It was found, however, that the continued supply of

  machining liquid in large quantities in the usable range

  swimming often causes breakage of the wire and does not allow to implement a larger machining current. When the wire electrode is heated excessively or insufficiently cooled, it tends to break. There is thus a limit to the heat sink capacity of the electrode wire

  which has a smooth and circumferential peripheral surface

  on its length crossing the machining interval.

  With the usual wire electrode having a usable surface

  Smoothing, it has also been observed that the gases produced by the discharges and / or the electrolytic decomposition of the machining liquid supplied tend to adhere to the surface of the surface.

  the electrode and to separate it from the cooling liquid

  of energy, thus acting as a thermal isolator

  and also allowing gaseous discharges, of a nature

  essentially thermal, to develop between them.

  An important object of the invention is therefore to provide a new configuration circulating wire EDM electrode having a larger heat-emitting capability than the conventional configuration wire electrode.

  Another important object of the invention is to provide a method of

  wire-type EDM machining die which provides a greater machining efficiency than the prior art

  Other objects of the invention will emerge from the description

following.

  According to a first aspect, the invention provides a circulating wire EDM electrode consisting of an elongated member having a thickness or diameter between

  0.05 and 0.5 mm, preferably not less than 0.1 mm,

  a rough peripheral surface along its length, or

  its peripheral surface having protrusions and projections

  surface features arranged in a predetermined uniform pattern. The projections or recesses shall have a height or depth of one-fiftieth. and one-third, preferably between one-thirtieth and one-fifth, even more preferably between one-tenth and one-fifth, of the thickness of the elongated element or, preferably, in

  the range between 5 and 20 microns.

  The rough peripheral surface can be arranged in

  arranging the elongate member by a plurality of conductive wires twisted together, or interlaced or braided, to provide a predetermined uniform pattern of surface protrusions and recesses. A rough peripheral surface

  substantially similar electrode can be obtained by

  one or more relatively thin conductor wires on a relatively thick conductor wire, or on a beam of

  thin wires, or covering a conductive wire

  thick or a bundle of fine wires by means of a

  fabric of relatively fine conductive wires.

  The rough peripheral surface may alternatively be

  picking up protrusions and indentations on a conventional wire-wire electrode by mechanical, electrochemical or thermal technique, or

  any combination of these. The technique of

  Mechanical mage includes sanding and knurling. Sandblasting can use grains having a size of between 10 and 500 meshes. For knurling, the diameter of the stitches is determined by the size and number by

  surface unit of the projections presented by the mole tool

  floor. A rotating matrix can also be used to

  Mechanically roughen a rough peripheral surface over the usual wire electrode, pulling the wire through the die. Chemical forming includes electroless plating and etching, while electrochemical forming includes electroforming and electro-etching. Thermal forming can be practiced by plasma spraying

  fine corpuscles of metal powder. We can also use

  spray or atomize a powder to

  hold a rough peripheral surface on the wire electrode

  habitual, by applying to him corpuscles.a powder atomized.

  Specifically, the invention provides an electrode for

  circulating wire or electro-machining electrode

  erosion of the circulating wire type, in which an element

  ge, having a thickness of between 0.05 and 0.5 mm,

  greater than 0.09 mm, is moved along a predetermined path to thereby form a running wire machining electrode when it is placed near the workpiece and forms a machining gap immersed in a machining liquid,

  a machining electric current is applied between the elec-

  trode and the piece for electro-erosion removal of

  of the latter, thus machining this part, said path of the electrode and the part being displaced relatively

  to form a machined contour in the room, gaseous bubbles

  its being formed by the decomposition of the machining liquid as the machining stream passes through the gap, which bubbles tend to adhere to the machining surface of the electrode, thereby acting as a heat insulator between the electrode and the machining liquid, characterized in

  what, in order to facilitate the detachment of said bubbles

  on the machining surface, the elongate member has a rough peripheral surface on a portion thereof, which has projections and recesses arranged in a predetermined uniform pattern, the projections or recesses having a height or depth between a fiftieth and a third, preferably between one-thirtieth and one-fifth, and even more preferably between one-tenth and one-fifth,

  the thickness of the elongated element, or equal to a

taken between 5 and 20 microns.

  According to a second aspect, the invention provides a method for

  electro-erosion of a conductive part of the electrical

  cited by means of a circulating wire machining electrode, characterized in that it comprises the measures of a) producing an elongated element having a thickness of between 0.05 and 0.5 mm, preferably greater than 0 , 09 mm; b) axially moving the elongated member along a predetermined path to thereby form the circulating wire machining electrode, and placing the workpiece proximate the running wire machining electrode to form a machining gap; c) providing a machining liquid in the machining gap; d) applying a machining current between the electrode and the workpiece through the machining gap to electro-erode the material from the workpiece, thereby machining the workpiece while allowing gaseous bubbles to form in the workpiece. gap by electrical decomposition of the machining liquid, bubbles which tend to adhere to the machining surface of the electrode, thereby acting as a heat insulator between the machining surface and the machining liquid; e) relatively moving said path of the electrode and the workpiece to form a contour machined therein; and f) promoting the detachment of said gas bubbles from

  of the machining surface by providing the elongated element with a sup-

  rough peripheral face on an expanse of it which

crosses the room.

  The rough peripheral surface is here characterized by projections and surface recesses arranged in a predetermined uniform pattern, the projections or recesses having a height or depth of between one-fiftieth and one-third, preferably between one-thirtieth and one-fifth, and still more preferably between a tenth and a fifth,

  the thickness of said elongate member.

2 4 94 155

  Such a rough peripheral surface favorable to the objects of the invention is produced by constituting the elongated element by means of a multiplicity of twisted conductive wires,

  woven or braided. A rough peripheral surface of elec-

  substantially similar trode can be obtained by twisting one or more relatively thin conductive wires on a relatively thick conductive wire, or in a spiral configuration, or over a bundle of thin conductive wires, or by covering a relatively thick conductive wire or beam or a twist of relatively fine threads, using

  of a fabric of relatively thin conductive wires, to form

  a predetermined uniform pattern of protrusions and

surface treatments.

  A favorable rough peripheral surface can also be obtained by forming the protrusions and recesses on a common and smooth running wire machining electrode,

  by using a mechanical forming technique, chemically

  As described above, it has been found that, by virtue of a novel configuration as described, the machining surface of the circulating wire machining electrode can cool rapidly and efficiently, allowing use a machining current of greater intensity or density, without danger of destructi

  wire electrode, while maintaining the machining stability.

  The end result is a remarkable increase in removal speed and machining efficiency. It has also been found that the effect of using a described wire electrode configuration to promote thermal emission is further increased when, in process measurement b), the elongated element is moved along a path predetermined by the upper side of the piece towards its lower side Embodiments of the invention will now be described, by way of example, in conjunction with the accompanying drawings, in which: FIG. essential section, repe9s4et5

  schematically a typical machine for machining

  erosion wire circulating on which the electrode wire according to the invention can be implemented and to follow the method according to the invention; Figure 2 is a cross section of an elongated member according to the invention, having the form of a twisted or woven strand, or made by twisting or weaving seven relatively thin conductive wires;

  FIG. 3 is a side view of a twisted wire element

  dice according to the invention; FIG. 4 is a side view of a woven or interlaced son element according to the invention; FIG. 5 is a longitudinal sectional view of an element according to the invention made of wire having a rough peripheral surface with projections and recesses arranged according to the invention; a pattern

  particular predetermined uniform, mechanically produced,

  electrically, electrochemically or thermally

  FIG. 6 is a side view of an element according to the invention.

  in-wire having a rough peripheral surface

  picking by passing through a rotating die;

  FIG. 7 is a side view of an element according to the invention;

  yarn composition comprising a core yarn on which a finer yarn is spirally wound;

  FIG. 8 is a sectional view of an element according to the invention;

  yarn composition which comprises a core yarn and seven yarns wound or twisted thereon; Figure 9 is a sectional view of an element according to the invention which comprises seven twisted son, cordless core

  FIG. 10 is a sectional view of an element according to the invention;

  which includes five wires twisted together; and Fig. 11 is a graph showing machining currents

  maxima that can be applied without causing the

  truction of the electrode, for various elementary electrodes

  according to the invention and according to the prior art.

  Referring now to FIG.

  current-type circulating wire spark erosion machine which comprises a vertical column 1 carrying a horizontal extension 2. A machine head 3 is slidably carried by the horizontal extension 2, and can be moved vertically by a motor 4 for adjustment.

  from its vertical position. A circulating electrode electrode

  E, according to any one of the elongated elements according to the invention shown in FIGS. 2 to 10, or a variant thereof, having a thickness of between 0.05 and 0.5 mm, preferably between 0, 09 and 0.5 mm, is stored in a reel

  supply 5 mounted in the upper position in the

  1, and it is guided by braking rollers 6a, 6b and a guide roller 7 in the horizontal extension 2, then by rollers 8, 9 and a guide-matrix 10, in

  the head 3 towards the zone of a piece W, which is mounted rigidly

  on a work table or support. This table is carried by a device with sliding sliding tables 12, 13

  which is in turn supported by the base 14 of the machine.

  The electrode wire E is placed in machining relation with the part W by the guide matrix 10 located on the upper side of the part in the head 3, and a sliding guide 15 located on the lower side of the part in a hollow arm. 16 which extends horizontally from the vertical column 1 below the piece W. The wire electrode is placed between the

  guide-die 10 and the sliding guide 15. A unit 17 of

  wire drag is disposed below the sliding guide, inside the hollow arm 16, and is constituted as a pair of rollers 17a and 17b reciprocally abutting, one of which is driven by a motor (not shown) for

  ensure continuous traction of the electrode wire E. A provision

  The thread extraction device 18 is furthermore disposed in the arm 16 and comprises three endless belts 19, 20 and 21.

2 4 94 1 55

  wound respectively on pairs of rollers 22, 23; 23, 26 and 24, 25. In this arrangement, the rollers 23 and

  24 may be driven by one or more motors (not shown).

  to move the belts and to grasp the wire electrode E first between the moving belts 19 and 20 and then between the moving belts 20 and 21. The wire electrode E which

  escapes from between the moving belts 20 and 21, is assembled

  wheat in a collection box 27.

  Against the tensile force exerted on the filament

  electrode E by the drive rollers 17a and 17b, downstream of the workpiece W, the braking rollers 6a and 6b on the supply side of the wire are driven in such a way as to apply a suitable braking force to the wire electrode E, of such in such a way that the latter continuously flows from the delivery side 5 to the collection side 27 at an appropriate axial circulation speed and under adequate tension. The guide roller 7 and the extraction unit 18 serve to change the direction of flow of the wire from the supply side to the

  the coin and from the latter to the collection side 27.

  Downstream of the guide guide wheel 7, an electrically conductive roller 28 is disposed in abutting relation with the guide roller 8 to drive the electro-erosion current to the electrode wire E; it is for this purpose connected

  by a broom 29 at an output terminal of a power source 30

  electro-erosion reactor with the other output terminal connected

  electrically to the workpiece W by a conductive block (not shown

  sented). The EDM current thus passes into the

  machining range G formed between the electrode wire E and the workpiece W, and bathed in a machining liquid. A pump 31 draws the machining liquid into a reservoir 32 to supply it to a reserve chamber 33 attached to the head 3, depending on its

  lower end and having an opening 34 of four-

  liquid. The machining liquid injected into the chamber 33 is provided by the opening 34 on the circulating electrode wire E and is carried with it into the machining gap G. A tubular electromechanical transducer 35 may be arranged to allow the passage of the electrode wire E through

2 4 9 4 15 5

  him. When excited by a power source (not

  presented), this transducer communicates a mechanical vibration

  high-frequency electrode to the circulating electrode E, in order to facilitate an electro-erosion process. This transducer 35 is carried by an L-shaped arm 36 which hangs from the wall

  horizontal extension 2, its vertical position

  shim being adjusted by a position adjustment unit 37.

  The crossed tables 12 and 13 carrying the working support 11 are driven in an X-Y plane, by means of a motor 38 for the X axis and a motor 39 for the Y axis to which

  they are respectively coupled to drive. The modalities

  38 and 39 are excited by X-axis and Y-axis drive signals provided by a digital control unit 40 to move the workpiece by

  relative to the longitudinal axis of the electrode wire E, and for

  a given relative starting position of machining

  set in advance in the numerical control unit 40, to move the workpiece W with respect to the axis of the circulating wire electrode E along a prescribed prescribed cutting path

  in advance in the numerical control unit 40.

  According to the invention, the electrode wire E can advantageously

  have the shape of an elongated element consisting of a multi-

  plicity of fine wires twisted or woven with each other. Figure 2 shows a cross-section of seven

  son 51 which form an elongated element 50 according to the invention.

  It can be seen that the elongated element according to the invention has a rough peripheral surface with projections 52 and recesses 53. According to the invention, it has been found that the projections 52 or the recesses 53 must have a height or depth h between , fiftieth and a third, preferably between one thirtieth and one fifth, even more preferably

  between one-tenth and one-fifth, the thickness D of the ele-

  The projections or recesses must have a height or depth of preferably between 5 and 15 microns. It will be seen that the elongated element 50 according to the invention, having a given cross-sectional area or a thickness D, has a surface much larger than that of a conventional wire EDM wire. circulating, whose cross section is circular and has the same cross-sectional area, and is even greater than that of the circular cross-section wire having the same thickness D. The elongated element 50 according to the present invention thus a larger surface area that emits heat. In addition,

  the outer indentations 53 and the indentations

  both advantageously provide pockets

  for the machining liquid which serves as a cooling agent

  on the one hand and machining agent on the other hand, thereby allowing the electrode surfaces to be cooled with increased efficiency, and allowing

  uniform and free of machining fluid in the inter-

  machining valle. Since the elongated element 50

  the electrode wire E is displaced axially, a sur-

  movable cylindrical machining face is obtained and third

  The passages are spirally formed on this surface, which adds the advantage of favoring the supply of the liquid.

  machining in the narrow machining interval.

  In addition, it has been found that the structure of the elongated element according to the invention effectively removes the thermal barrier.

  produced by the gaseous bubbles which form consecutively

  on the surface of the electrode due to decomposition

  machining fluid through machining discharges and / or

  trolyse. It has been determined that the rough formations of the

  elongated mobile device according to the invention facilitate the detachment

  gaseous bubbles from the surface of the electri-

  these bubbles, which act as a heat insulator between the surface of the electrode and the machining liquid,

  which favors all the more the thermal emission and the cooling

  dissement of the surface of the electrode. The cooling effect

  As the attenuation is increased, the elongated element

  larger machining current without undergoing a thermal destruction

  because of the heat that develops during the transition

2494 155

  of a larger current. The end result is an increase

  remarkable speed of removal and thus a remarkable shortening of the total machining time required

  to perform a given machining operation. Another advantage

  the twisted and woven structure of the elongated element

  according to the invention is that it has greater resistance to

  while retaining the flexibility of a thread,

  than the usual single-wire structure. Any accidental breakage

  lace of one or the other of the elementary wires constituting the circulating wire machining electrode, due to a possible

  arc discharge, does not lead to the destruction of electricity

trode herself.

  Typical elongate elements of twisted or woven structure are shown in FIGS. 3 and 4 and are designated respectively by references 61 and 62. Twisted wire electrode

  61 consists of seven elementary sons 51, while the

  woven electrode 62 shown in FIG. 4 consists of three elementary wires 51. In general, each elementary wire 51

  may have a diameter of between 0.01 and 0.03 mm.

  The thickness of the elongated member having a twisted or woven wire structure can change to a large extent as the voltage varies, and thus can be adjusted.

  regulating the voltage applied to it. This eliminates prematurely

  the need to change the electrode element for various shapes or machining configurations, like this

  was essential in the prior art.

  It will be understood that various modifications of the structure according to

  the invention with twisted or woven wires are possible. For example

  In this case, a relatively thick core wire coated with a fabric or twist of relatively thin wires can be produced. The core wire can be replaced by a wire bundle or by wires

twisted.

  The rough peripheral surface of the elongate member according to the invention can also be obtained by mechanically, chemically, electrochemically or thermally forming projections or recesses in a uniform pattern.

  predetermined on the elementary electrode.

  Fig. 5 shows an elongate member 63 consisting of a

  wire electrode E having projections 63a and recesses

  63b which can be formed by electroless veneering, chemical veneering, electro-plating, sputter deposition.

  those, spraying, sintering or knurling. Figure 6 shows

  be another elongated element 64 consisting of a wire-electrode

  E stretched through a rotating die so as to pre-

  grooves or projections 64a and grooves or recesses

  64b. Figure 7 shows another elongated member shape 65 which consists of a relatively thick wire electrode E on which a wire 66 is spirally wound

  thin, so as to have protrusions 65a and

  65b. The protrusions 63a, 64a, 65a and the recesses

  63b, 64b, 65b shall have a height or depth

  between one-fiftieth and one-third, preferably

  be one thirtieth and one fifth, and even more preferentially

  between one-tenth and one-fifth of the thickness of the

  E. Preferably, the height or depth should

  in general, be between 5 and 15 microns.

  Here again, the structure of the elongated element according to the invention effectively removes the thermal barrier produced by the gas bubbles which develop consecutively on the

  electrode surface resulting from the electrical decomposition

  trolytically and / or by discharge of the machining liquid. The

rough matings 63a, 63b; 64a, 64b; 65a, 65b on the moving electrode E facilitate the detachment of these gas bubbles from the surface of the electrode, these bubbles acting as a thermal insulator between the surface of the electrode and the machining liquid, thus promoting the thermal and

  the cooling of the surface of the electrode.

  FIG. 8 shows an elongated element 67 consisting of a core wire 68 and seven wires 69 twisted on this core,

2494 15.5

  while Figure 9 shows an elongated element 70 without core and formed by seven son 69 twisted. FIG. 10 shows an elongate element 71 formed by five twisted wires 69,

wireless core forming.

EXAMPLE

  An elementary wire 65, 67 shown in FIGS. 7 and 8

  is a core wire having a diameter of 0.1 mm

  and in seven twisted wires each having a diameter of 0.065 mm.

  It is designated by the reference El. An elementary wire 70

  shown in Figure 9, designated by the reference E2,

  is: seven wires each having a diameter of 0.075 mm. An elementary wire 71 shown in FIG. 10, designated by the reference E3, consists of five wires each having a diameter

  0.09 mm. The elementary sons El to E3 all have a

  cross-sectional face of 0.0314 mm. An elementary thread

  63 shown in FIG. 1 consists of a wire having a di-

  meter of 0.2 mm and having projections 63a distributed uniformly

  formally on its peripheral surface and having a height of 13 microns. This elementary wire is designated by the reference E4. An elementary wire 64 shown in FIG. 6, designated by the reference E5, consists of a wire having a diameter of 0.2 mm drawn in a rotating die so as to have edges 64a having a height of 10 microns and grooves 64b. having a depth of 15 microns. A common elementary wire, consisting of a single wire having a diameter of

  0.2 mm, is designated by the reference EO.

  The highest machining current that can pass in each of these elementary wires without causing its destruction is measured during the EDM machining of a steel

  S55C complies with Japanese industry standards, using

  a process liquid composed of a water-based liquid

  having a specific resistance of 2x10 ohm-cm. The results

  States of these tests are shown in the graph shown in Figure 11. It is seen that all the elementary son El to E5 according to the invention are much higher than the usual elementary wire EO, and they have a much better cooling capacity. For example, the elementary wire E3 has a heat emission capacity of 4.6x104 10 Kcal / m · h. C., and the elementary wire E4.a capacity of 4.6x104 Kcal / m2. h. These two values are much greater than the emission capacity of the usual simple electrode wire which

3 2

  is 3x10 Kcal / m.h. c. It has also been noted that, in this regard, it is desirable to move the elementary wire from top to bottom through the workpiece for the circulating wire EDM operation as shown in FIG.

Figure 1.

Claims (33)

Claims.   1. EDM electrode with circulating wire, characterized in that it consists of an elongated element having a thickness of between 0.05 and 0.5 mm, presenting a rough peripheral surface over a range of   the latter, this surface being provided with projections and with   shades conforming thereon in a predetermined uniform pattern, said protrusions and recesses having a size of one-fiftieth to one-third of the thickness of the elongated element.   2. Electrode according to claim 1, characterized in that said size is between a trentiene and a fifth of the thickness.   3. Electrode according to claim 1, characterized in that   that said size is between one tenth and one - one-fourth of the thickness.   4. Electrode according to claim 1, characterized in that   that said size is between 5 and 20 microns.   5. Electrode according to any one of claims 1 to 4,   characterized in that the thickness is between 0.1 and 0.5 mm.   6. Electrode according to claim 1, characterized in that the rough peripheral surface is a surface of the contour of the elongated element produced by twisting a multiplicity of threads together.   7. Electrode according to claim 1, characterized in that the rough peripheral surface is a surface of the contour of the elongated element produced by weaving a multiplicity of son.   8. Electrode according to claim 1, characterized in that the rough peripheral surface is a surface of the contour of the elongated element produced by winding at least   a relatively thin wire on a relatively thick wire.   9. Electrode according to claim 1, characterized in that the rough peripheral surface is a surface of the   outline of the elongate element produced by forming the lees and recesses on a wire.   10. Electrode for electro-erosion machining of the circulating wire type in which an elongated element having a thickness of between 0.05 and 0.5 mm is moved according to   a predetermined path to constitute a machining electrode   circulating wire wound when placed near a workpiece to form a machining gap immersed in a machining liquid, a machining electric current being applied between the electrode and the workpiece for electromechanical removal. erosion of the material of the workpiece, thereby machining the workpiece, said path and the workpiece being moved relatively to form a contour machined in said workpiece, gaseous bubbles being formed by the decomposition of   machining fluid when the machining current passes through   these bubbles tend to adhere to the machining surface of the electrode, characterized in that, in order to facilitate the detachment of the gas bubbles from   of the machining surface, the elongated element   rough peripheral face on an extent thereof which has projections and recesses arranged according to a predetermined uniform pattern.   11. Electrode according to claim 10, characterized in that the projections and the recesses have a size between one fiftieth and one third of the thickness of the elongated element. 12. Electrode according to claim 11, characterized in that the size is between one thirtieth and one fifth thickness.   13. Electrode according to claim 11, characterized in that la.téille is between one tenth and one fifth thickness.   14. Electrode according to claim 10, characterized in that   that the protrusions and recesses are of a similar size between 0.5 and 20 microns.   15. Method for machining a conductive part by electro-erosion   electricity by means of a circulating wire machining electrode, characterized in that it comprises the measures of   a) making an elongated element having a thickness of   between 0.05 and 0.5 mm; b) axially moving the elongated member along a predetermined path to form therewith the machining electrode   wire, and place the coin and the   machining trode by circulating wire to form a machining gap; c) providing a machining liquid at the interval; d) applying a machining current between the electrode and the workpiece through the machining gap to electro-erode the material from the workpiece, thereby machining the workpiece while allowing gaseous bubbles to form in the meantime by the electrical decomposition of the machining liquid, these bubbles having a tendency to adhere to the machining surface of the electrode, thus acting as a heat insulator between the machining surface and the liquid of the electrode. 'machining; e) relatively moving the path and the workpiece to form a contour machined therein; and f) promoting detachment of the gas bubbles from the machining surface by providing the elongated member with a rough peripheral surface along a length thereof crosses the room.   Method according to claim 15, characterized in that the rough peripheral surface is provided with projections   and recesses placed in a uniform pattern pre-   determined. 17. The method of claim 16, characterized in that the projections and the surface recesses have a   between one-fiftieth and one-third of the thickness the elongated element.   18. The method of claim 17, characterized in that   the size is between one thirtieth and one fifth.   19. The method of claim 17, characterized in that   the size is between one-tenth and one-fifth.   20. Process according to claim 17, characterized in that   the size is between 5 and 20 microns.   21. The method of claim 15, characterized in that the measures a) and f) comprise the torsade of a multiplicity   of threads for preparing the elongated element having the rough rip.   22. Method according to claim 15, characterized in that the measures a) and -f) comprise the weaving of a multiplicity   of wire to prepare the elongate member having the perimeter surface rough phérique.   23. A method according to claim 15, characterized in that, in the measure a), the elongated element is formed by a wire having a diameter of between 0.05 and 0.5 mm, and in that the measurement f) comprises forming on the surface of said wire a multiplicity of projections and recesses arranged according to   a predetermined uniform pattern through a forming process.   24. The method of claim 23, characterized in that the forming process is a veneer without the aid electricity.   25. The method of claim 23, characterized in that   the forming process is chemical etching.   26. The method of claim 23, characterized in that   the forming process is electro-plating.   27. The method of claim 23, characterized in that   the forming process is electrochemical etching.   28. The method of claim 23, characterized in that   the forming process is sandblasting.   29. The method of claim 23, characterized in that   the forming process is knurling.   30. The method of claim 23, characterized in that the forming process is a powder projection using of plasma.   31. The method of claim 23, characterized in that the forming process is a spray or atomization a powder.   32. The method of claim 23, characterized in that   the forming process is sintering.   The method of claim 23, characterized in that the forming process comprises the step of drawing the wire through a rotating die to prepare the elongated element.