Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/20—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils
  • H01B3/22—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances liquids, e.g. oils hydrocarbons
• • 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

• This invention relates to the electro-discharge machining of metals for reproducing from or on a block of metal the form or surface contour of a model by electrically cutting or eroding the block of metal with an electric spark or are from the model and, more particularly, to liquid hydrocarbon compositions in which such electric machining is carried out with the model and the block of metal immersed in the hydrocarbon composition for enhancing the speed and efficiency of the operation.
• This application is a continuation-in-part of copeuding application Serial -No. 13,411, filed October 22, 1959.
• Such metal working techniques are well known and, as will be understood, provide a method for rapidly and readily forming in a block of metal various shapes and configurations which would be quite difiicult to obtain by other more classic means of metal working such as turning, grinding, cutting, etc.
• Such an electro-erosion forming operation may be carried out, as is well understood, with the anode and cathode surrounded by air or various other media. Certain enhanced results are achieved if the medium surrounding the anode and cathode at least in the portions thereof where the eroding or forming action occurs, is a liquid medium or a medium other than air, advantageously circulated around the electrodes. Such a liquid medium has been found to produce a number of advantages in operation.
• a surrounding liquid medium absorbs heat energy liberated during the operation and also may aid materially in the physical elimination of particles of metal eroded by the electrical operation from the anode.
• a hydrocarbon liquid medium is provided, particularly adapted for use in an electro-erosion operation of the character described, and utilizing a dielectric hydrocarbon liquid which, particularly, permits augmenting the speed of erosion and permits, for the same consumption of energy, an increase in the yield of the process as well as substantially diminishing the consumption or erosion or necessary wastage of the cathodic driving model or electrode.
• Such liquid medium comprises primarily hydrocarbons having a carbonto-hydrogen weight ratio of equal to or greater than 7, which hydrocarbons are readily obtained from various treatments of certain petroleum fractions and otherwise in accordance with this invention as noted in more detail below; and, preferably, such liquid hydrocarbon medium includes aromatic and solvent-extracted cuts or fractions of petroleum distillates and/or monocyclic monoalkyland polyalkyl-benzenes of the general formula C H and having the above noted carbonhydrogen weight ratio, all treated in accordance herewith to produce a liquid dielectric medium adapted for achieving the enhanced results disclosed in an electroerosion operation of the character to which this invention relates.
• hydrocarbons for use in connection herewith will be understood and are well known in the art of electrodischarge machining (and, particularly, for so-called inside machining where the entire workpiece is immersed in the dielectric bath, as compared with outside machining where merely a film of dielectric liquid is maintained between the electrode and a workpiece forming a spark gap therewith).
• hydrocarbon liquids in accordance herewith and/or the dielectric baths including such hydrocarbons may vary somewhat depending upon or in accordance with the particular machining operation being used and/ or such characteristics thereof as the particular type of apparatus being used, the desired speed of cutting, the configuration being cut, etc.
• a hydrocarbon having an excessively high vapor tension such as associated with hydrocarbons boiling above about 260 C. at atmospheric pressure.
• hydrocarbon baths in accordance herewith may comprise one or another of individual hydrocarbons disclosed, or mixtures thereof, or mixtures of various hydrocarbons which, individually and alone, may not come within the definitions hereof provided that such mixture thereof in the bath as used is in accordance with the ranges of weight ratios of carbon to hydrogen, etc., in accordance herewith.
• hydrocarbon materials may be obtained from a variety of sources and by a variety of diiferent means or processes.
• they may be produced by thermal or catalytic decomposition or conversion of hydrocarbons, by chemical synthesis techniques, by physical separation or distilla tion, or by combinations thereof. Satisfactory results in accordance herewith have been achieved with hydrocarbon materials prepared, in known manner, by such well known cracking processes as catalytic platforming, or reforming or hydrofining, by steam cracking, etc., whereby cuts or fractions are produced rich in alkylsubstituted aromatic hydrocarbons.
• compositions embodying and for practicing this invention Utilizing compositions embodying and for practicing this invention, however, it is noted that, for any given electrical potential, the products embodying this invention, while producing a faster forming or cutting or eroding rate, also achieve a status of operation where the anodic model is less consumed.
• compositions embodying and for practicing this invention as oil immersents for the cutting electrodes of an electro-erosion device of the character described and as mentioned above, one may note a number of comparative data collected with regard to an other composition in accordance with this invention, which will be here designated as Product D.
• compositions embodying and for practicing this invention may note the comparative results achieved with, for example, a lubricating oil composition such as that described above as Product C, as compared with another product according to this invention.
• a composition which may be herein designated as Prodnot B
• Prodnot B a composition
• the designated mixture has the characteristics noted below:
• Such enhanced advantages may include the aspect of the superficial hardening to a certain extent through the surface of, for example, steel treated in accordance with the foregoing, and the tempering thereof, as one would expect from the intense heating by the electrode discharge of rough steel in a bath of oil, as one might temper a steel member by heating it and then quenching it in a bath of oil.
• comparative data which, according to the foregoing, has been developed from various satisfactory uses of, for example, Product A as compared with Product B in an operation embodying and in accord ance with this invention.
• comparative data in Table IV below illustrative of the invention, is set forth as between a Product A in accordance with the invention and the previous Product B:
• any material treated in accordance with this invention may be expected to be altered as the material is heated, in connection with the electro-erosion thereof, in the presence of a circulating liquid in accordance with this invention, and, as will be well understood, the superior treatment of any material in accordance with this invention will, as is well understood, be calculated so as to accommodate whatever treating or other metallurgical or crystalographic changes may be undergone in accordance with the electro-erosion heating as immersed in one or another of the materials or compositions set forth herein.
• the electro-erosion treatment according to this invention dependingupon, to some extent, the particular composition of the metal being treated, may, indeed, have no eflect whatsoever, metallurgically, on the metal being treated.
• the surface hardening mentioned above depends, on a large measure, on the viscosity, among other factors, of the composition in which the metal being treated is immersed during the electro-erosion treatment.
• PRODUCT H An alkyl-substituted mono-aromatic hydrocarbon corresponding approximately to the formula 0 1-1 boiling between about 205 225 C. at atmospheric pressure, and having a carbon-hydrogen weight ratio of about 8.05 was used as the dielectric liquid bath for an electro ero'sion machining operation on a block of extra hard steel (at about 1% carbon) with a copper electrode under power input of the order of 1 ,kw. at a frequency of about 3600 hertz, to achieve satisfactory cutting conditions and a desirably fine surface finish.
• the cutting speed here was increased by a factor of about 1.65 that of the conventional technique, while the wastage or consumption of the copper electrode was only about half that experienced with the conventional hydrocarbon outside the ranges in accordance herewith.
• this invention is not limited to the utilization of the particular materials set forth in the various illustrative examples above, it may be noted that the alkyl benzene materials within the weight ratio disclosed have produced particularly favorable results especially when it is desired to obtain a fine finish on the surfaces being machined, as well as when it is particularly desired to utilize relatively low power input (of the order of 1 kw.) for the machining operation. If, on the other hand, it is desired to utilize a higher power input for machining, other aromatic extracts may be preferred, such as those obtained in the course of solvent refining of petroleum distillates during lubricating oil manufacture, as exemplified by such materials as noted above as Product A or Product B, etc.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (7)

Cited By (1)

Citations (4)

• 0
  • NL NL120664D patent/NL120664C/xx active
  • NL NL244666D patent/NL244666A/xx unknown
• 1958
  • 1958-10-24 FR FR777436A patent/FR1254411A/fr not_active Expired
• 1959
  • 1959-10-23 BE BE583966A patent/BE583966A/fr unknown
  • 1959-10-23 CH CH7978559A patent/CH403111A/fr unknown
  • 1959-10-23 GB GB35977/59A patent/GB877597A/en not_active Expired
  • 1959-10-23 DE DEC20032A patent/DE1110341B/de active Pending
• 1961
  • 1961-07-24 US US125931A patent/US3084245A/en not_active Expired - Lifetime

Patent Citations (4)

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