EP0314711A1 - Liquide pour usinage edm - Google Patents

Liquide pour usinage edm

Info

Publication number
EP0314711A1
EP0314711A1 EP19880902779 EP88902779A EP0314711A1 EP 0314711 A1 EP0314711 A1 EP 0314711A1 EP 19880902779 EP19880902779 EP 19880902779 EP 88902779 A EP88902779 A EP 88902779A EP 0314711 A1 EP0314711 A1 EP 0314711A1
Authority
EP
European Patent Office
Prior art keywords
liquid
machining
lamellae
conductive
dielectric
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19880902779
Other languages
German (de)
English (en)
French (fr)
Inventor
Charles Frei
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Agie Charmilles New Technologies SA
Original Assignee
Agie Charmilles New Technologies SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Agie Charmilles New Technologies SA filed Critical Agie Charmilles New Technologies SA
Publication of EP0314711A1 publication Critical patent/EP0314711A1/fr
Withdrawn legal-status Critical Current

Links

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
    • 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
    • B23H1/08—Working media

Definitions

  • the present invention relates to a liquid for EDM machining, to one of its manufacturing processes and to its use in EDM machining.
  • EDM EDM
  • solid and conductive particles such as carbon or metal particles such as aluminum or copper plays an important role in initiating landfills.
  • These particles can also come from electrode debris due to erosion or the decomposition of the dielectric. Their concentration varies during the machining, this all the more that the circulation of the dielectric and therefore the evacuation of the polluted dielectric, more or less trapped in the machining slot separating the two electrodes, are often difficult.
  • a dielectric liquid facilitating the adjustment of certain machining parameters, in particular that of the flow rate of the machining liquid, has been described in Swiss patent 627,393. It is a stable suspension of solid and conductive particles or semi -conductive, with a particle size less than or equal to 5 ⁇ m. This liquid makes it possible in particular to choose a larger inter-electrode distance (also called here "gap" or machining slot), which reduces the risks of short circuit, improves the regularity of the circulation of the dielectric as well as the cooling speed. and therefore increases the stability of the machining.
  • This improvement in the circulation of the dielectric also allows a good homogenization of the suspension and consequently a regular distribution of the discharges, as well as a uniform priming of the latter, which increases the stability of the priming conditions (waiting time t d ) improves the state of the machined surface and reduces the mechanical stresses and consequently the risks of deformation or rupture for the electrodes.
  • the dead times, and consequently the yield and the speed of machining, (in particular the quantity of eroded material per unit of time) increase.
  • the quality of the dielectric depends on the concentration, the composition, the shape and the dimensions of the particles suspended in the liquid.
  • These particles are preferably constituted by a metal or by graphite powder in suspension in a usual dielectric, such as water or a mixture of hydrocarbons. The best results were obtained with irregularly shaped solid particles with a large number of roughness.
  • the object of the present invention is therefore a dielectric machining liquid, constituted by a stable and homogeneous dispersion of conductive or semi-conductive lamellae in a dielectric liquid.
  • the largest dimension of these lamellae can reach several tens of microns, while their thickness can be of the order of only a few nanometers. They have an "average diameter” which can range from 0.001 to 50 microns, preferably from 0.1 to 5 microns. By “average diameter” is meant the average of the largest of the three dimensions of these strips.
  • suspensions or dispersions of the colloidal type that is to say of which the particle size is less than one micron, in particular in order to simplify the handling and recycling of the machining liquid.
  • the concentration of these strips in the dielectric can vary between
  • the lamellae used are preferably constituted by metals which are good conductors of electricity, such as aluminum, copper, iron. Good results can also be obtained with the powders of certain metalloids such as graphite, for example. We also cite silver, magnesium, cobalt, nickel, zinc, cadmium, molybdenum. It may be advantageous to use a metal with a low vaporization point, such as, for example, indium, magnesium, cadmium, zinc, (already mentioned), tin or lead (despite their toxicity) and also bismuth although it is the least conductive of metals.
  • alloys such as brass, certain steels or bronzes, or certain semiconductors like molybdenum sulfide MoS 2 .
  • dielectric liquid it is possible to use water, preferably deionized, a hydrocarbon, or a mixture of hydrocarbons, such as kerosene or certain mixtures commercially available, such as that marketed by ELF under the name FLUX ELF 1 and 2 , by BP under the reference BP 180, BP 200 or BP 250, by AVIA under the name AVIA IME
  • SHELL 43 or UNIVOLT 54, by SHELL under the name SHELL.
  • liquids can be mixed together such as, for example, an emulsion of hydrocarbons in water.
  • the criteria, which must be taken into account when choosing this liquid, are: - good stability and homogeneity of the dispersion, - rapid deionization, - low viscosity, - absence of toxicity - high flash point - good filterability, - little chemical reactivity, in particular with ion exchange resins possibly used to regenerate the dielectric in the case of an aqueous dielectric as well as any other property simplifying the handling and regeneration of the machining liquid, as well as favoring the cooling of the electrodes during machining.
  • it must preferably be transparent, so that the operator can follow the work, must be brought into contact with both ferrous and non-ferrous metals and must not make foams.
  • the dispersions according to the present invention can also contain one or more additives, such as those usually used for dielectric machining liquids. They can be, in particular, anti-rust or anti-corrosion agents such as 1,1,1-tri (hydroxymethyl) ethane, or alkanolamines or certain of their derivatives such as borates, phosphates or their salts with fatty acids or arylsulfonamidocarboxylic acids, or like other soaps, optionally added with water-soluble metal derivatives such as hydroxides, borates, nitrates, nitrites, sulfates or oxides.
  • additives such as those usually used for dielectric machining liquids. They can be, in particular, anti-rust or anti-corrosion agents such as 1,1,1-tri (hydroxymethyl) ethane, or alkanolamines or certain of their derivatives such as borates, phosphates or their salts with fatty acids or arylsulfonamidocarboxylic acids, or
  • surfactants or surfactants preferably nonionic agents
  • Some, such as soaps can also act as anti-corrosion agents and improve the shiny appearance of cut surfaces.
  • the salts of diethanolamine and fatty acid such as oleic, palmitic or stearic acid. Good results can also be obtained with diethylethanolamine, aminoethylethanolamine, triisopropanolamine, for example.
  • the dielectric is a mixture of hydrocarbons and water, for example, they can also play the role of an emulsifier.
  • a water-based liquid it can also be a conductivity modifier capable of increasing the specific resistivity of deionized water.
  • the present invention also relates to a method of manufacturing such a dielectric dispersion, as well as a means for implementing it.
  • This process is characterized by the fact that a powder, a paste or another liquid containing conductive or semi-conductive lamellae is added to a dielectric liquid and that sufficient stirring is carried out to obtain a stable and homogeneous dispersion. It is thus possible to add a conductive or semiconductive powder to an insulating liquid, optionally containing a surfactant, while effective agitation is maintained by any known means, the quantity of powder corresponding to a predetermined concentration.
  • the contamination of the machining liquid generally increases during machining due to the dispersion of conductive debris due to this machining, it may be advantageous to continuously adjust the concentration of the conductive particles during of this machining, possibly after filtration.
  • machining liquid would be obtained by mixing two different fluids, one free of conductive lamellae, the other containing a given concentration of these slats.
  • the proportions of this mixture are automatically adjusted, either so as to modify the rate of conductive particles as a function of the variation of certain machining parameters, or in order to maintain a constant rate.
  • the addition of conductive strips to the during machining may be carried out so as to maintain the conductivity of the dielectric at a predetermined constant value, this in order to obtain good machining stability.
  • the addition of the lamellae can also be carried out so as to modulate their concentration, depending for example on a machining parameter, such as the average ignition time or the low-level sparking rate, as described in the Swiss patent 632,176 or in Swiss application 384/87. It is possible to avoid this continuous adjustment of the content of conductive particles by appropriately adjusting the flow rate of the machining fluid, for example as a function of the quantity of material removed.
  • the concentration of conductive particles in the latter can be monitored by known means, either optically, using photoconductive elements or photometric sensors for example, or electrically, using measurements of the ignition delay for example. .
  • the present invention also relates to a use in electroerosive machining by electrical discharges (EDM machining) of the dispersions described above. This use can be carried out both in wire electrode cutting machines and in driving electrode machines.
  • EDM machining electrical discharges
  • These machines may be provided with devices making it possible to prevent possible sedimentation of the dispersions according to the present invention, for example devices for agitation with ultrasound arranged in the supply circuit and renewal of the machining liquid.
  • They may also have a circuit controlling the concentration of the conductive or semi-conductive lamellae in the machining liquid of the present invention to the variation of one or more several machining parameters.
  • machining liquids of the present invention can have a large number of compositions, methods of preparation and possible uses. Only some of these possibilities will be described below, by way of examples, and with the aid of the appended drawing.
  • Figure 1 shows schematically the measuring cell used to determine the ignition characteristics of the machining liquids according to the invention.
  • FIG. 2 is a diagram representing the variation of the voltage or potential difference between the electrodes as a function of time during machining by electroerosive electric discharges supplied by rectangular voltage pulses.
  • FIG. 3 represents the variation over time of an average statistical value of the initiation time t d carried out on approximately 30 discharges for known machining liquids and for the liquids of the present invention.
  • FIG. 4 represents the variation of the logarithm of this statistical mean of the ignition delay t d as a function of the inverse of the interelectrode distance g, (or of the electric field applied to the electrodes).
  • FIG. 5 shows diagrammatically the mounting on an EDM machine of a device for readjusting the concentration of conductive strips in the machining liquid.
  • metal powders are available on the market, in particular because of their use in metallurgy, for the production of parts by compression, with or without sintering, or by fusion (metallization, solders, solder pastes, etc.) ..) or their use as a catalyst or in exothermic (flame cutting, explosives, pyrotechnics, aluminothermic, etc.) or also as composite materials (foundry molds, reinforced plastics) or also associated with mineral and organic binders, as constituents in printing inks, paints, coatings and various coatings, etc.
  • the metal powders with which the various dispersions used for the tests described below have been prepared, are sold by BAUDIER under the brand POUDMET.
  • the graphite lamellae are marketed for example by LONZA under the reference K S 2.5, by ACHESON COLLOIDEN B.V. under the name DAG 386 or - still sold under the name "Madagascar graphite".
  • the dielectric liquid used to disperse these metal or graphite lamellae is a paraffinic oil sold by BP under the name BP 180.
  • An orifice connected to an appropriate device allows the cell to be emptied and cleaned between two series of measurements involving different liquids.
  • FIG. 1 This cell consists of a glass cylinder 1.
  • the mounting of these electrodes has has been done with care to ensure as much as possible their parallelism.
  • Their outside and inside diameter are 64 and 40 mm respectively.
  • the electric discharges bursting between these electrodes 2 and 3 are supplied by a voltage of 400 V and rectangular pulses of current of 3 A having a duration of 1 ⁇ s.
  • the dispersions of conductive particles are injected between the electrodes 2 and 3 through a network 4 of capillary tubes connected to the reservoirs containing the dispersions which it is desired to test. This injection is carried out at the speed of approximately 1 ml / mm.
  • Each series of measurements of the average initiation time is carried out for approximately 10,000 discharges, using a measurement and calculation circuit of known type, not shown in FIG. 1. An orifice connected to an appropriate device (not shown) used to empty and clean the cell between two series of measurements involving different liquids.
  • phase d priming during which a given potential difference in level is established and applied between the two electrodes during the time t d , the discharge having not yet burst, and the discharge phase during which the discharge bursts and causes the erosion of the electrodes during the time t e .
  • Two successive pulses are separated by time t o .
  • the characteristics of the priming phase are strongly influenced by the dielectric properties of the machining fluid.
  • the concentration of aluminum grains is the same in both cases: 10 -4 by volume as well as the average diameter of these grains: approximately 6 microns.
  • a t d value of approximately 16 ⁇ s is obtained for the dispersion A according to the invention, while it reaches approximately 1000 ⁇ s for the dispersion B of non-lamellar particles.
  • the machining liquids of the present invention have the same advantages, but to an even greater extent, than the dielectrics described in Swiss patent 627393, namely the possibility of machining with an even greater distance between electrodes while retaining a sufficiently short priming time, and without the constraint of limiting the flow rate of the machining liquid in order to maintain a certain concentration of conductive particles, the latter being introduced voluntarily into the machining fluid.
  • the discharge regime has good stability; this further improves that of the machining as it appears on figure 3 where the oscillations of the value of t d in the course of time are much weaker (between 8 and 20 ⁇ s approximately) in the case of dispersion A than in that dispersion B (between approximately 130 and 4000 ⁇ s).
  • the lamellar dispersions of the present invention it is possible to determine the value of the interelectrode distance g by measuring the statistical mean value t d with constant concentration of conductive particles and by working with the same interelectrode voltage. This was not possible with the known dispersions, because the slope of the line representing the variations of log t d as a function of 1 / g varied from one measurement to another, while it remains substantially constant with the dispersions according to the present invention.
  • This stability of the dispersion also contributes to the stability of the machining.
  • FIG. 5 shows diagrammatically a device integrated into an electroerosion machining machine making it possible to adjust and follow the evolution of the concentration of conductive particles of a machining liquid according to the present invention, for example by measuring times of successive waits, and subjecting it to at least one machining parameter by adjusting this concentration during machining by adding appropriate conductive or semiconductor lamellae.
  • the workpiece-electrode 11 to be machined and the tool-electrode 12 are immersed in a machining liquid 13 retained in a tank 14 and arranged at a distance g from one another.
  • An electrical circuit (of known type, not shown) is connected to these electrodes 11 and 12 and supplies them with the pulses necessary for the bursting of erosive electrical discharges through the liquid 13 bathing the machining slot 15.
  • the electrode- tool 12 can be a driving tool whose slow penetration into the workpiece is programmed so that the slot 15 has a depth g determined as the erosion progresses. This depth g can be variable or constant.
  • the tool electrode 12 can also be a wire electrode traveling through an orifice passing through the part 11 from side to side and cutting it along a predetermined path as the erosion progresses.
  • Other types of movements (vertical, rotary, etc.) relating between the part 11 and the electrode 12 can be printed on the latter by means of known devices placed in the guide heads, in the case of a wire electrode, or in the fixing head, in the case of a driving-in electrode.
  • the machining liquid 13 can be injected into the slot 15 thanks to at least one injection nozzle connected by a line 16 to the supply circuit.
  • a driving-in electrode it can also be injected through a pipe formed in the electrode itself and connected to the supply circuit.
  • the liquid brought in by this pipe or pipe 16 was obtained by mixing, under mechanical or ultrasonic agitation, in a container 17, a dielectric liquid with a concentrated dispersion of conductive or semi-conductive lamellae, optionally coated with a surface-active binder, produced in that same liquid.
  • the dielectric liquid comes from a reservoir 18 in which it is stored after having been taken from the tank 14 and then cleaned and regenerated by passing through a system 30 comprising decanters, filters, ion exchange resins, etc.
  • the concentrated dispersion is taken from a reservoir 19 by any pumping means of known type, at a rate controlled by a metering system 20 controlled by a signal emitted by the control circuit 23.
  • Devices 21 and 22 for measuring the concentration of particles are disposed respectively downstream of the machining slot and at the outlet of the container 17.
  • the measurements are carried out optically or electrically in a known manner , or by a cell measuring the waiting time like that described in the Swiss patent 632 340, or by a device measuring the low level of sparks such as that described in the Swiss application
  • the device 21 can be replaced by a device performing measurements directly in the machining slot.
  • a circuit connected to the tool electrode 12, produced for example as described in US Pat. No. 3,825,714, makes it possible to measure the waiting time t d for each discharge and to calculate a representative average statistical value. In particular, it makes it possible to detect respectively the instant when the starting voltage is started to apply and the instant when the discharge begins.
  • These devices 21 and 22 generate electrical signals, compare them to a reference value and allow the control of the dosing system 20 thanks to the logic control circuit 23. It is thus possible to regulate the concentration of the conductive particles dispersed in the liquid 13 in l 'slaving to at least one machining parameter, the variations of which are communicated to this circuit 23.
  • the spark-off distance g is kept constant by a servomotor provided with an adjustment device, such as that described, for example, in US Pat. No. 4,049,942, both not shown in FIG. 5.
  • the control circuit 23 actuates the dosing system 20 until the concentration measured by the device 22 reaches this reference value. It is thus possible to change in a predetermined manner the composition of the machining liquid (and the average priming time) during machining.
  • Such a device makes it possible to maintain the stability of the machining conditions and to regulate the latter so as to machine at the optimum speed while ensuring the quality of the machined surfaces. It is understood that the above examples have no limiting character, and are given only by way of illustration. Many modifications can be made, in particular with regard to the various ingredients making up these dispersions, their proportions, the methods of preparation of these dispersions and the conditions of their use in electroerosion, without departing from the scope of the present invention.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
EP19880902779 1987-04-03 1988-04-05 Liquide pour usinage edm Withdrawn EP0314711A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH128987A CH670785A5 (enrdf_load_stackoverflow) 1987-04-03 1987-04-03
CH1289/87 1987-04-03

Publications (1)

Publication Number Publication Date
EP0314711A1 true EP0314711A1 (fr) 1989-05-10

Family

ID=4206949

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19880902779 Withdrawn EP0314711A1 (fr) 1987-04-03 1988-04-05 Liquide pour usinage edm

Country Status (4)

Country Link
EP (1) EP0314711A1 (enrdf_load_stackoverflow)
JP (1) JPH01500983A (enrdf_load_stackoverflow)
CH (1) CH670785A5 (enrdf_load_stackoverflow)
WO (1) WO1988007428A1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2269756A2 (en) 2007-01-16 2011-01-05 Charmilles Technologies S.A. Devices designed to treat defects of the residual white layer left by the electrical discharge machining process

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5189276A (en) * 1990-02-13 1993-02-23 Mitsubishi Denki K.K. Method and apparatus for treating the dielectric used in electrical discharge machining
JP2590633B2 (ja) * 1990-11-30 1997-03-12 三菱電機株式会社 放電加工装置
JPH07108419A (ja) * 1993-10-08 1995-04-25 Sodick Co Ltd 放電加工装置及びこの装置を用いる放電加工方法
JP2001252828A (ja) * 2000-02-24 2001-09-18 Charmilles Technol Sa 放電加工機用加工液の負荷粒子及びその製造方法
ES2234508T3 (es) * 2000-12-22 2005-07-01 Charmilles Technologies S.A. Dispositivo de purificacion de liquidos de mecanizado para maquinas de electroerosion.
CN101954517B (zh) * 2009-07-20 2012-07-18 财团法人工业技术研究院 放电加工液及放电加工方法
JP6531263B2 (ja) * 2016-02-29 2019-06-19 ミクロン精密株式会社 表面処理装置および表面処理方法
CN115055770B (zh) * 2022-06-25 2024-08-13 湖北欧米隆精密机械有限公司 一种电火花成型机油槽用放油机构

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5543849A (en) * 1978-09-25 1980-03-27 Hitachi Ltd Integrated circuit device
JPS5993239A (ja) * 1982-11-17 1984-05-29 Inoue Japax Res Inc 放電加工用加工液
JPH0643012B2 (ja) * 1984-05-23 1994-06-08 株式会社井上ジャパックス研究所 放電加工方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8807428A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2269756A2 (en) 2007-01-16 2011-01-05 Charmilles Technologies S.A. Devices designed to treat defects of the residual white layer left by the electrical discharge machining process

Also Published As

Publication number Publication date
JPH01500983A (ja) 1989-04-06
WO1988007428A1 (fr) 1988-10-06
CH670785A5 (enrdf_load_stackoverflow) 1989-07-14

Similar Documents

Publication Publication Date Title
WO1988007428A1 (fr) Liquide pour usinage edm
EP1064100B9 (fr) Moyens de pulverisation electrohydrodynamique
CH649025A5 (fr) Procede et appareil d'usinage electriques d'une piece a usiner.
FR2492297A1 (fr) Procede et appareil de forage par electro-erosion
WO2020008312A1 (fr) Fil electrode a couche poreuse pour electroerosion
EP3479660B1 (fr) Dispositif pour le traitement électrique d'un corps gras d'origine végétale
CA2476184C (fr) Procede de nettoyage de la surface d'un materiau enduit d'une substance organique, generateur et dispositif de mise en oeuvre
CH632176A5 (fr) Procede et dispositif pour usiner par etincelage erosif.
FR2476523A1 (fr) Procede et appareil d'usinage par electro-erosion a coupe par fil
DE3310995A1 (de) Edm-verfahren und -vorrichtung
CH627393A5 (fr) Procede d'usinage par decharges electriques erosives.
EP1127647B1 (fr) Charge de particules pour liquides d'usinage pour machines à électroérosion, son procédé de fabrication, son utilisation et liquide d'usinage contenant une telle charge
FR2477932A1 (fr) Procede et dispositif d'usinage par electro-erosion
CN111020572A (zh) 一种电火花沉积金刚石线锯丝生产装置
FR2516000A1 (fr) Procede et dispositif d'usinage par decharges electriques
JPS6059314B2 (ja) 放電加工液
CH638125A5 (fr) Procede et dispositif pour l'usinage par etincelage.
SU1637979A1 (ru) Способ электроконтактной наплавки ферромагнитными порошками и устройство дл его осуществлени
EP2546017B1 (fr) Procédé et dispositif de soudage à l'arc avec électrode consommable comprenant en alternance des cycles de soudage par court circuit et des cycles de soudage par transfert pulsé
FR2473362A1 (fr) Procede et appareil d'usinage electrique avec liquide d'usinage interpose entre l'outil et la piece a usiner
EP1512469B1 (fr) Procédé et installation pour la lubrification de cylindres de laminage
DE1058169B (de) Elektrode fuer die Funkenerosion unter Verwendung eines dielektrischen Mediums
FR2480165A1 (fr) Procede perfectionne pour l'usinage par decharges electriques
FR2492294A1 (fr) Procede de soudage en bout par etincelage et assemblages soudes obtenus par ledit procede
FR3149528A1 (fr) Fil électrode

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19890502

17Q First examination report despatched

Effective date: 19900611

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19901103