US3750441A - Device for forming workpieces by means of underwater spark discharges - Google Patents

Device for forming workpieces by means of underwater spark discharges Download PDF

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Publication number
US3750441A
US3750441A US00119158A US3750441DA US3750441A US 3750441 A US3750441 A US 3750441A US 00119158 A US00119158 A US 00119158A US 3750441D A US3750441D A US 3750441DA US 3750441 A US3750441 A US 3750441A
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US
United States
Prior art keywords
thread
electrodes
ignitor
wire
diameter
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.)
Expired - Lifetime
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US00119158A
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English (en)
Inventor
G Schneider
J Mammann
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.)
Siemens AG
Siemens Corp
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Siemens Corp
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Publication date
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Publication of US3750441A publication Critical patent/US3750441A/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/68—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts by incorporating or moulding on preformed parts, e.g. inserts or layers, e.g. foam blocks
    • B29C70/82—Forcing wires, nets or the like partially or completely into the surface of an article, e.g. by cutting and pressing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/06—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves
    • B21D26/10—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure by shock waves generated by evaporation, e.g. of wire, of liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B1/00—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/313—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of semiconductor devices with two electrodes, one or two potential barriers, and exhibiting a negative resistance characteristic
    • H03K3/315—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of semiconductor devices with two electrodes, one or two potential barriers, and exhibiting a negative resistance characteristic the devices being tunnel diodes
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma

Definitions

  • Appl' ll9l58 generated in a liquid by an undersurface spark discharge has two electrodes in the liquid and mutually [30] Foreign Application Priority Data separated so as to define a spark gap.
  • a capacitor bat- Mar. 18, 1970 Germany P 20 12 783.7 y is connected across the electrodes and an isnimr is suspended between the electrodes in the spark gaps.
  • US. Cl. 72/56 The 8 has a Synthetic carrier thread made of 51 Int.
  • Our invention relates to a device for forming workpieces by the action of pressure waves produced by underwater spark discharges occasioned by the discharge of a bank of capacitors over a spark gap. A thin metal wire is suspended across the spark gap.
  • the flash over of the underwater spark discharge occurs between the electrodes located in the water after the high voltage charged capacitor batteries are connected into the electrode circuit provided the electric field strength determined by the electrode spacing and condensor voltage is sufficient for collision ionizing the water or corresponding transmission medium. Since in the known apparatus, the stored voltage of 25 to 30 kv is not exceeded, the electrode spacing for a free flashover is limited to several centimeters.
  • the ignition must be introduced in a manner other than by a free flash-over.
  • the best known measure is to use an ignitor in the form of a thin wire as an electrical conductor which is tensioned between the electrodes and becomes vaporized in an explosion-like manner when the capacitor discharge is initiated.
  • ignition wires must be used having a diameter less than 0.1 mm. This type of thin wire is difficult to handle because of its small mechanical strength.
  • the wires are completely destroyed in the ignition action, so that each time the ignition wire must be threaded anew into the forming device.
  • a device for forming workpieces hydroelectrically is disclosed in patent application, Ser. No. 834,690 of H. Seiffert and G. Hausler, filed June 19, 1969 assigned to the assignee of the instant application and having the title: Device for Forming workpieces Hydroelectrically.
  • the application discloses how the abovementioned difficulties are prevented.
  • an ignitor is used which I has a nonconductive carrier with a conducting jacket. The nonconductive carrier is not destroyed by an underwater discharge. The ignitor can, therefore, be pulled through the electrodes for a renewed discharge so that the spark gap is again bridged by the metallic jacket of the ignitor.
  • the metallic jacket can for example be produced through chemical or electro-chemical deposition or through vapor deposition. In order to achieve a reproducible forming of material, it is necessary that the metal content and electrical characteristics of the metallic jacket of such a type of ignitor be as constant as possible.
  • a metallic wire is embedded in the surface region of a carrier comprising a thermoplastic synthetic thread so as to precisely define a metal surface zone.
  • the ignitor is dimensioned so that the diameter of the metal wire is from 0.02 to 0.06 mm and the diameter of the synthetic thread is from 0.5 to 1 mm.
  • the ignitor according to the invention has all the desired characteristics required for the forming of material by means of underwater spark discharge.
  • the mechanical strength is determined by the insulating synthetic carrier.
  • the synthetic thread is not destroyed either by the underwater spark or by the exploding of metal wire. Threading and pulling a new length of the ignitor into the spark gap in a forming device is therefore very simple.
  • the consistency with which material is formed by a device equipped with the ignitor of the invention is guaranteed by the constancy of the wire diameter and its ever constant electrical characteristics.
  • the cross-section and material characteristics of the metal embedded in the thread can be optimally selected for the best forming efficiency.
  • FIG. 1 illustrates in section an ignitor according to the invention
  • FIG. 2 is a schematic representation of an apparatus for producing the ignitor of FIG. 1;
  • FIG. 3 illustrates a device for forming workpieces hydroelectrically which is equipped with an ignitor according to the invention.
  • FIG. 1 illustrates in section an ignitor according to the invention wherein reference numeral 11 designates a thin copper wire having a diameter of 0.05 mm and is embedded in the surface region of the synthetic thread 12.
  • reference numeral 11 designates a thin copper wire having a diameter of 0.05 mm and is embedded in the surface region of the synthetic thread 12.
  • the wire 11 is shown embedded in thread 12 so that the surface of the wire coincides with the surface of the thread to provide the latter with metal surface zone.
  • the thread 12 can be made of polyamide and has a diameter of 0.9
  • the mechanical strength of the ignitor is determined by the synthetic thread 12. Thread 12 is not destroyed by the electrical discharge so that for a new discharge another length of the thread can be pulled into the spark gap of the forming device.
  • the copper wire 11 can be optimally selected with respect to its crosssection for obtaining a large forming action.
  • FIG. 2 schematically illustrates, for example, a simple apparatus for economically producing an ignitor according to the invention in practically any desired length.
  • the metal wire 21 and the synthetic thread material 22 is directed from delivery spools 23 and 24 through a heated pull nozzle 25.
  • the temperature of the pull nozzle 25 is selected so that the metal wire 21 is melted into the surface region of thread 22. For polyamide this temperature is approximately 250 C.
  • the synthetic thread 22 is preheated in a preheating nozzle 26 before the metal wire 21 is embedded into the thread.
  • the metal wire 21 and the synthetic thread 22 are pulled through the nozzle 25 by transport rollers 27 with a constant velocity, for example with a velocity of 0.] m per second.
  • the finished ignitor 28 is taken up by the take-up spool 29.
  • the nozzle 25 is heated by means of a heating winding 210 disposed in a thermal insulation 21].
  • FIG. 3 illustrates a device used for forming workpieces having a cylindrical configuration.
  • This device is equipped with an ignitor according to the invention and makes it possible to form an elongated cylindrical workpiece according to the hydro-spark method with multiple discharges and a one-time installation of the workpiece in the workpiece forming device.
  • reference numeral 1 denotes the workpiece to be formed, namely, a water-filled tube which is sealed on top and bottom by insulating parts 2.
  • two electrodes 3a, 3b extend into the water chamber and are screwed into the terminal brackets 4 of the hydro-spark installation.
  • the ignitor 5 starts from a reel 6 and is guided through the bore of earth grounded electrode 3a.
  • electrode 3b is connected to a bank of capacitors 7 via three-electrode spark gap 8. When the capacitor bank is energized, a high voltage is applied to electrode 3b.
  • the non-conductive carrier of the ignitor 5 is transported along the electrode 3b such that the segment of the ignitor 5 between the electrodes will again conductively bridge the electrodes.
  • the second discharge can follow provided the assembly remains tight after the first discharge.
  • the assembly will remain tight because the second and subsequent discharges are of significant consequence only if the preceding discharge results in a slight forming of the workpiece.
  • the means required to ensure a good seal are only symbolically represented by the sealing rings 9.
  • an apparatus for forming workpieces by pressure waves generated in a liquid by an undersurface spark discharge comprising two electrodes immersed in the liquid and mutually separated so as to define a spark gap, a capacitor battery connected across the electrodes, and an ignition assembly suspended between the electrodes in said spark gap, said assembly being provided with a carrier of thermoplastic synthetic thread, a thin metal wire of a diameter smaller than the diameter of said thread disposed in and partially surrounded by said thread, to thereby expose a defined surface area of said wire coincidental with the outside of such thread.
  • An ignition assembly for use in an apparatus for forming workpieces with pressure waves generated in a liquid by an undersurface spark discharge, wherein: said ignition assembly comprises; a thermoplastic synthetic carrier thread having an exposed surface, and a metal wire partially encapsulated by said carrier thread to thereby define an exposed surface zone of said wire at said thread outer surface.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Fluid Mechanics (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Resistance Heating (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
US00119158A 1970-03-18 1971-02-26 Device for forming workpieces by means of underwater spark discharges Expired - Lifetime US3750441A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2012783A DE2012783C3 (de) 1970-03-18 1970-03-18 Vorrichtung zum Umformen von Werkstücken durch Unterwasser-Funkenentladung

Publications (1)

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US3750441A true US3750441A (en) 1973-08-07

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US00119158A Expired - Lifetime US3750441A (en) 1970-03-18 1971-02-26 Device for forming workpieces by means of underwater spark discharges

Country Status (5)

Country Link
US (1) US3750441A (enrdf_load_stackoverflow)
CH (1) CH527008A (enrdf_load_stackoverflow)
DE (1) DE2012783C3 (enrdf_load_stackoverflow)
FR (1) FR2083363B1 (enrdf_load_stackoverflow)
GB (1) GB1301955A (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4030329A (en) * 1976-07-12 1977-06-21 Viktor Nikolaevich Chachin Device for electrical discharge forming
RU2186648C2 (ru) * 2000-04-14 2002-08-10 Волгоградский государственный технический университет Устройство для электровзрывной запрессовки труб
RU2245753C1 (ru) * 2003-07-30 2005-02-10 Волгоградский государственный технический университет (ВолгГТУ) Устройство для электровзрывной запрессовки труб
RU2378075C1 (ru) * 2008-04-22 2010-01-10 Государственное образовательное учреждение высшего профессионального образования Волгоградский государственный технический университет (ВолгГТУ) Электрогидроимпульсный способ запрессовки труб в труднодоступных местах
RU2378074C1 (ru) * 2008-04-22 2010-01-10 Государственное образовательное учреждение высшего профессионального образования Волгоградский государственный технический университет (ВолгГТУ) Электрогидроимпульсный способ запрессовки труб в труднодоступных местах
US20100175449A1 (en) * 2007-05-22 2010-07-15 Andreas Stranz Ignition device for explosive forming
US7905129B1 (en) * 2009-09-21 2011-03-15 Ford Global Technologies, Llc Method and tool for contracting tubular members by electro-hydraulic forming before hydroforming
US20110067470A1 (en) * 2009-09-21 2011-03-24 Ford Global Technologies, Llc Method and Tool for Expanding Tubular Members by Electro-Hydraulic Forming
US20110088442A1 (en) * 2009-10-19 2011-04-21 Ford Global Technologies, Llc Hydromechanical Drawing Process and Machine
US20120312060A1 (en) * 2011-06-10 2012-12-13 Ford Global Technologies, Llc Method and Apparatus for Pulsed Forming, Punching and Trimming of Tubular Members
US20130067976A1 (en) * 2011-09-20 2013-03-21 Ford Global Technologies, Llc Apparatus and Method Using Reduced Volume Electro-Hydraulic Chambers for Trimming and Joining Panels
US10012063B2 (en) 2013-03-15 2018-07-03 Chevron U.S.A. Inc. Ring electrode device and method for generating high-pressure pulses
RU2690798C1 (ru) * 2018-07-18 2019-06-05 Федеральное государственное автономное образовательное учреждение высшего образования "Сибирский федеральный университет" Устройство для запрессовки труб в трубную решетку
US11648741B2 (en) * 2020-05-19 2023-05-16 The Boeing Company Methods of embedding an elongate susceptor within a thermoplastic body
WO2025015062A1 (en) 2023-07-12 2025-01-16 Ene29, Inc. High-power electrical discharge tool with plastic wire

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU3581784A (en) * 1984-01-16 1985-07-25 Budd Company, The Fiber-reinforced pultrusion
DE3419816C2 (de) * 1984-05-28 1987-04-30 Dornier System Gmbh, 7990 Friedrichshafen Vorrichtung zur Erzeugung hoher Drucke
US4943755A (en) * 1985-05-20 1990-07-24 Mitsubishi Denki Kabushiki Kaisha Magnetic shielding with constant-current coils for CRT
FR2648076B1 (fr) * 1989-06-09 1991-11-15 Boulet D Auria Terlizzi Fil gaine profile destine notamment a former un insert d'electro-soudure
DE102016010730A1 (de) * 2016-09-07 2018-03-08 Karl Klink Gmbh Vorrichtung und Verfahren zum Umformen von Blechen

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3200626A (en) * 1961-12-26 1965-08-17 Gen Electric Electrical explosion forming
US3228221A (en) * 1961-09-18 1966-01-11 Aerojet General Co Apparatus for forming material
US3603127A (en) * 1968-06-24 1971-09-07 Siemens Ag Device for forming workpieces hydroelectrically

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3228221A (en) * 1961-09-18 1966-01-11 Aerojet General Co Apparatus for forming material
US3200626A (en) * 1961-12-26 1965-08-17 Gen Electric Electrical explosion forming
US3603127A (en) * 1968-06-24 1971-09-07 Siemens Ag Device for forming workpieces hydroelectrically

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4030329A (en) * 1976-07-12 1977-06-21 Viktor Nikolaevich Chachin Device for electrical discharge forming
RU2186648C2 (ru) * 2000-04-14 2002-08-10 Волгоградский государственный технический университет Устройство для электровзрывной запрессовки труб
RU2245753C1 (ru) * 2003-07-30 2005-02-10 Волгоградский государственный технический университет (ВолгГТУ) Устройство для электровзрывной запрессовки труб
US20100175449A1 (en) * 2007-05-22 2010-07-15 Andreas Stranz Ignition device for explosive forming
US9393606B2 (en) * 2007-05-22 2016-07-19 Cosma Engineering Europe Ag Ignition device for explosive forming
RU2378075C1 (ru) * 2008-04-22 2010-01-10 Государственное образовательное учреждение высшего профессионального образования Волгоградский государственный технический университет (ВолгГТУ) Электрогидроимпульсный способ запрессовки труб в труднодоступных местах
RU2378074C1 (ru) * 2008-04-22 2010-01-10 Государственное образовательное учреждение высшего профессионального образования Волгоградский государственный технический университет (ВолгГТУ) Электрогидроимпульсный способ запрессовки труб в труднодоступных местах
US7905129B1 (en) * 2009-09-21 2011-03-15 Ford Global Technologies, Llc Method and tool for contracting tubular members by electro-hydraulic forming before hydroforming
US20110067470A1 (en) * 2009-09-21 2011-03-24 Ford Global Technologies, Llc Method and Tool for Expanding Tubular Members by Electro-Hydraulic Forming
US20110067467A1 (en) * 2009-09-21 2011-03-24 Ford Global Technologies, Llc Method and tool for contracting tubular members by electro-hydraulic forming before hydroforming
US8567223B2 (en) 2009-09-21 2013-10-29 Ford Global Technologies, Llc Method and tool for expanding tubular members by electro-hydraulic forming
US8534106B2 (en) * 2009-10-19 2013-09-17 Ford Global Technologies, Llc Hydromechanical drawing process and machine
US9375775B2 (en) 2009-10-19 2016-06-28 Ford Global Technologies, Llc Hydromechanical drawing process and machine
US20110088442A1 (en) * 2009-10-19 2011-04-21 Ford Global Technologies, Llc Hydromechanical Drawing Process and Machine
US8534107B2 (en) * 2011-06-10 2013-09-17 Ford Global Technologies, Llc Method and apparatus for pulsed forming, punching and trimming of tubular members
US20120312060A1 (en) * 2011-06-10 2012-12-13 Ford Global Technologies, Llc Method and Apparatus for Pulsed Forming, Punching and Trimming of Tubular Members
US20130067976A1 (en) * 2011-09-20 2013-03-21 Ford Global Technologies, Llc Apparatus and Method Using Reduced Volume Electro-Hydraulic Chambers for Trimming and Joining Panels
US8667823B2 (en) * 2011-09-20 2014-03-11 Ford Global Technologies, Llc Apparatus and method using reduced volume electro-hydraulic chambers for trimming and joining panels
US10012063B2 (en) 2013-03-15 2018-07-03 Chevron U.S.A. Inc. Ring electrode device and method for generating high-pressure pulses
US10077644B2 (en) 2013-03-15 2018-09-18 Chevron U.S.A. Inc. Method and apparatus for generating high-pressure pulses in a subterranean dielectric medium
RU2690798C1 (ru) * 2018-07-18 2019-06-05 Федеральное государственное автономное образовательное учреждение высшего образования "Сибирский федеральный университет" Устройство для запрессовки труб в трубную решетку
US11648741B2 (en) * 2020-05-19 2023-05-16 The Boeing Company Methods of embedding an elongate susceptor within a thermoplastic body
WO2025015062A1 (en) 2023-07-12 2025-01-16 Ene29, Inc. High-power electrical discharge tool with plastic wire
FR3150969A1 (fr) 2023-07-12 2025-01-17 ENE29 Inc, Outil de décharge électrique à haute puissance à fil plastique

Also Published As

Publication number Publication date
FR2083363B1 (enrdf_load_stackoverflow) 1974-03-01
DE2012783B2 (de) 1973-09-27
DE2012783C3 (de) 1974-05-09
FR2083363A1 (enrdf_load_stackoverflow) 1971-12-17
GB1301955A (enrdf_load_stackoverflow) 1973-01-04
DE2012783A1 (de) 1971-10-07
CH527008A (de) 1972-08-31

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