EP0245112A2 - Dispositif de perforation des feuilles - Google Patents

Dispositif de perforation des feuilles Download PDF

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Publication number
EP0245112A2
EP0245112A2 EP87304116A EP87304116A EP0245112A2 EP 0245112 A2 EP0245112 A2 EP 0245112A2 EP 87304116 A EP87304116 A EP 87304116A EP 87304116 A EP87304116 A EP 87304116A EP 0245112 A2 EP0245112 A2 EP 0245112A2
Authority
EP
European Patent Office
Prior art keywords
electrodes
electrode
film
capacitor
high voltage
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Withdrawn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
EP87304116A
Other languages
German (de)
English (en)
Other versions
EP0245112A3 (fr
Inventor
Alan James Clegg
John Colin Dinsdale Smith
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.)
Bcl Ltd
Original Assignee
Bcl Ltd
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 Bcl Ltd filed Critical Bcl Ltd
Publication of EP0245112A2 publication Critical patent/EP0245112A2/fr
Publication of EP0245112A3 publication Critical patent/EP0245112A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26F—PERFORATING; PUNCHING; CUTTING-OUT; STAMPING-OUT; SEVERING BY MEANS OTHER THAN CUTTING
    • B26F1/00—Perforating; Punching; Cutting-out; Stamping-out; Apparatus therefor
    • B26F1/26—Perforating by non-mechanical means, e.g. by fluid jet
    • B26F1/28—Perforating by non-mechanical means, e.g. by fluid jet by electrical discharges

Definitions

  • This invention is concerned with film perforating apparatus.
  • the film is drawn between opposing electrodes across which a high electrical potential is applied of sufficient magnitude to initiate spark discharges between the electrodes through the film.
  • Each discharge perforates the film forming a pore having a beaded edge derived from molten plastics material.
  • each electrode is energised from a single source, on the formation of the first spark discharge between a pair of electrodes all the current passes through that discharge and so precludes spark discharges between other electrodes.
  • the film is not perforated with the desired pattern of pores. It is known to limit such a current surge in electrode circuits by providing current limiting resistors so that discharges can take place between other electrodes.
  • the present invention is concerned with an improved film perforating apparatus for perforating synthetic plastics film with electrical spark discharges in which each electrode has an independent source of high potential.
  • an apparatus for perforating a synthetic plastics film by means of electrical spark discharges comprises a set of first electrodes directed towards but spaced from a second electrode or electrodes so defining a gap through which the film may be drawn between the first electrodes and the second electrode or electrodes, a capacitor associated with each first electrode, a unidirectional high voltage source and a switching means for electrically connecting the high voltage source across each capacitor for the purpose of charging each capacitor and then disconnecting each capacitor from the high voltage source and electrically connecting each charged capacitor between its associated first electrode and the second electrode or electrodes whereby each capacitor is discharged by an electric spark discharge passing through the film.
  • each first electrode is a rod directed towards the second electrode or electrodes.
  • the rod preferably has a sharp point.
  • the second electrode may consist of an electrically conducting film guide plate or roller, or a bar or a vane with which the film makes no. contact.
  • the second electrode consists of a series of rod electrodes, preferably pointed, directed towards and corresponding with the first electrodes.
  • the invention also includes a process for the perforation of synthetic plastics film comprising passing the film through a gap between a set of first electrodes spaced from a second electrode or electrodes and applying a high voltage across the first electrodes and second electrode or electrodes such that electrical discharges pass between the first electrodes and second electrodes through the film causing the film to be perforated wherein each first electrode is supplied with high voltage from a separate charged capacitor.
  • the invention also includes a plastics film when perforated by an apparatus in accordance with the invention.
  • a film 1 of polypropylene is drawn through a gap between a set of pointed rod electrodes 2 directed towards a second set of earthed pointed rod electrodes 3 which correspond mirror-like with the electrodes 2, connected to a stud 4 on a four stud switching unit 5 (one unit 5 for each electrode 2) which comprises a connector arm 6 mounted upon a common rotatable electrically insulated rod 7.
  • the connector arm 6 in its vertical position, as shown in Figures 1 and 2, electrically connects stud 4 to a diametrically opposite stud 8 in each of the units 5.
  • the connector arm 6 on each unit 5 electrically connects diametrically opposite studs 9, 10 as shown in dotted outline in Figure 2.
  • a capacitor 11, earthed by one terminal to a common earth 12 is connected by the other terminal to stud 8 on each unit 5 and each stud 8 is connected to corresponding stud 9.
  • the remaining stud 10 in each unit 5 is connected by a common line 13 to a high potential DC generator 14 which, itself, is earthed by its second terminal.
  • the film 1 is drawn at a constant speed between the electrodes 2, 3.
  • the rod 7 rotates at a predetermined rate (by means not shown) which, in turn, rotates each arm 6 in each unit 5 in unison.
  • the arm 6 in each unit 5 connects stud 10 to stud 9
  • current flows to the capacitors 11 charging them with respect to earth to a high potential up to the level of the generator 14.
  • the arm 6 in each unit 5 breaks contact with the studs 9, 10 and connects the studs 4, 8 when the charge on each capacitor 11 passes through to its associated electrode 2 and a spark discharge shown at 15 in Figure 2 occurs between each electrode 2 and its corresponding earthed electrode 3 through the film 1.
  • Each discharge 15 perforates the film forming a pore 16 ( Figure 3) which is edged with a bead 17 ( Figure 4) of molten plastic material which solidifies on cessation of the discharge.
  • the bead 17 reinforces the edge of the pore 16 and inhibits tearing.
  • the size of the pore 16 depends upon the current flowing and duration of the discharge which in turn depends upon the electrical capacity of the capacitors 11. As this can be determined with some precision, close control upon hole size can be obtained independently of the speed of travel of the film 1, unlike the electric spark perforation apparatus of the prior art in which the discharge ceases less precisely as a pore moves away from the electrode area and the spark gap becomes too long for the potential difference to maintain the discharge.
  • the distance apart of the pores 16 in the film 1 is determined in the transverse direction of the film 1 by the spacing of the electrodes 2 and in the longitudinal direction by the speed of travel of the film 1 and the speed of rotation of the rod 7.
  • the pores 16 may range in size from about 6 microns to several hundred microns depending upon the capacity of the capacitors 11 and the magnitude of the potential from the generator 14 and the thickness of the film 1.
  • the generator 14 was rated at 23 kilovolts and the capacitors 11 had a capacity of 3C picofarads.
  • Polypropylene film 1 of thickness 25 microns was used and pores 16 formed in the film 1 had a diameter of about 50 microns.
  • the second set of electrodes 3 are replaced by an earthed vane or plate set on edge or by an earthed roller over which the film 1 travels.
  • the stud 4 and electrode 2 may be removed and the arm 6 may have pointed ends and serve both as a connector for the charging of the capacitor 11 when in the horizontal position and as an electrode when in the vertical position. It is understood that a film produced by the apparatus or process of the present invention is included in the scope of the invention.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Forests & Forestry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
  • Treatments Of Macromolecular Shaped Articles (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
EP87304116A 1986-05-08 1987-05-08 Dispositif de perforation des feuilles Withdrawn EP0245112A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB08611256A GB2190028A (en) 1986-05-08 1986-05-08 Perforating plastics film
GB8611256 1986-05-08

Publications (2)

Publication Number Publication Date
EP0245112A2 true EP0245112A2 (fr) 1987-11-11
EP0245112A3 EP0245112A3 (fr) 1990-02-07

Family

ID=10597528

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87304116A Withdrawn EP0245112A3 (fr) 1986-05-08 1987-05-08 Dispositif de perforation des feuilles

Country Status (3)

Country Link
EP (1) EP0245112A3 (fr)
AU (1) AU7263587A (fr)
GB (1) GB2190028A (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5308180A (en) * 1991-12-09 1994-05-03 Minnesota Mining And Manufacturing Company Liquid applicator with metering insert
JP3298887B2 (ja) * 1993-06-11 2002-07-08 ミネソタ マイニング アンド マニュファクチャリング カンパニー レーザー加工複製工具

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2545208A (en) * 1946-04-19 1951-03-13 John W Meaker Electrical perforating apparatus
FR1393500A (fr) * 1964-02-12 1965-03-26 Papiers Abadie Sa Des Appareil pour la perforation électrique de matériaux en feuilles
US3385951A (en) * 1966-05-20 1968-05-28 Du Pont Apparatus for perforating and bonding moving sheets of material by electrical discharges
US3419752A (en) * 1964-09-11 1968-12-31 Philips Corp Multiple spark printer
DE2410060A1 (de) * 1974-03-02 1975-09-11 Texmato Ges Fuer Automatisieru Vorrichtung zum perforieren von folien
DE2523608A1 (de) * 1975-05-28 1976-12-02 Fraunhofer Ges Forschung Anordnung fuer die elektroperforation von papier
FR2399307A1 (fr) * 1977-08-05 1979-03-02 Molins Ltd Appareil destine a perforer une bande de papier en mouvement, en particulier une bande de papier pour bout de cigarette
CA1122266A (fr) * 1981-10-14 1982-04-20 James Cross Appareil de traitement par etincelles electriques

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1603515A (en) * 1977-08-05 1981-11-25 Molins Ltd Spark perforation of moving webs of material

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2545208A (en) * 1946-04-19 1951-03-13 John W Meaker Electrical perforating apparatus
FR1393500A (fr) * 1964-02-12 1965-03-26 Papiers Abadie Sa Des Appareil pour la perforation électrique de matériaux en feuilles
US3419752A (en) * 1964-09-11 1968-12-31 Philips Corp Multiple spark printer
US3385951A (en) * 1966-05-20 1968-05-28 Du Pont Apparatus for perforating and bonding moving sheets of material by electrical discharges
DE2410060A1 (de) * 1974-03-02 1975-09-11 Texmato Ges Fuer Automatisieru Vorrichtung zum perforieren von folien
DE2523608A1 (de) * 1975-05-28 1976-12-02 Fraunhofer Ges Forschung Anordnung fuer die elektroperforation von papier
FR2399307A1 (fr) * 1977-08-05 1979-03-02 Molins Ltd Appareil destine a perforer une bande de papier en mouvement, en particulier une bande de papier pour bout de cigarette
CA1122266A (fr) * 1981-10-14 1982-04-20 James Cross Appareil de traitement par etincelles electriques

Also Published As

Publication number Publication date
GB2190028A (en) 1987-11-11
GB8611256D0 (en) 1986-06-18
EP0245112A3 (fr) 1990-02-07
AU7263587A (en) 1987-11-12

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Inventor name: SMITH, JOHN COLIN DINSDALE