US 3895208 A
A burning electrode is used to produce metal-free paths in metal foil layer disposed upon insulator foils, in particular capacitor foils. A high-frequency relatively low voltage is applied to the burning electrode which is placed in direct contact with the metal foil. The contact portions of the electrode are continuously renewed, since the electrode is a circular disk which is elastically pressed against the metal foil, and the metal foil is supported by two guide rollers.
Description (OCR text may contain errors)
O United States Patent 11 1 BEST LABLE cor! 1111 3,895,208 Kraus July 15, 1975  METHOD AND DEVICE FOR THE 3,177,337 4/1965 Kohles 219/119 x PRODUCTION OF METAL-FREE PATHS 0N gig? Z METALIZED INSULATOR FOILS 3,562,479 2/1971 Karl et al. 219/119 X  Inventor: Hubert Kraus, Regensburg, 3,585,338 6/1971 Rosenthal et al. 219/68 Germany  Assignee: ISvilemenhs zgktiengesellschaft, Berlin & Primary Examiner j v- Truhe umc ermany Assistant ExaminerN. D. Herkamp  Filed: Apr. 15, 1974 Attorney, Agent, or Firml-lill, Gross, Simpson, Van  pp NO: 460,893 Santen, Steadman, Chiara & Simpson  Foreign Application Priority Data  APSTRACT Se t. 28 1973 German 2348904 A buinmg electiode i p y paths 1n metal fOll layer dlsposed upon lnsulator fo1ls,
in particular capacitor foils. A high-frequency rela- C(il 2l9/68B,223lp9/l tively low voltage is pp to the burning electrode  Field 383 384 which is placed in direct contact with the metal foil. The contact portions of the electrode are continuously  References Cited renewed, since the electrode is a circular disk which is elastically pressed against the metal foil, and the metal UNITED STATES PATENTS foil is supported by two guide rollers. 2,435,441 2/1948 Grouse 219/68 X 2,671,157 3/1954 Dubilier 219/68 7 Clams, 1 Drawmg Flgure METHOD AND DEVICE FOR THE PRODUCTION OF METAL-FREE PATHS ON METALIZED INSULATOR FOILS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a burning electrode used for burning a metal-free strip or path into metal layers upon insulator foils and more particularly, to a burning electrode for the production of metal-free margins for electric capacitor foils.
2. Prior Art The present invention is an improvement of the copending application, Ser. No. 459,621, corresponding to German application P23187544. In this patent application, tapes or wires are used as burning electrodes. They are wound from one coil onto a second one, or they are endless tapes supported on rollers. They usually contact the metal layer in the area ofa guide roller.
The above methods, however, are very cumbersome, and it is desirable to construct an electrode whereby the usual high production speeds can be applied without requiring the exchange of tapes or the threading of new tapes.
In addition, it is desirable to avoid that folds in the foil which may occur upon a guide roller, or the surface of the guide roller itself, can influence the quality of the metal-free path, which has previously influenced the quality of burn paths produced by the method of said invention.
SUMMARY OF THE INVENTION It has therefore been found desirable to provide an electrode which is able to operate at the high production speeds of capacitor foils.
It has also been found desirable to apply this electrode in such a way that foil folds upon guide roller or imperfection of the guide roller surface do not influence the quality of the burn path. To achieve these results, the electrode is a circular disk, and it is springingly pressed against the metal layer which is freely supported between two guide rollers. Said metal layer usually is a regenerable metallization.
These and other objects, features and advantages of the invention will be understood in greater detail from the following description and the associated drawings.
BRIEF DESCRIPTION OF THE DRAWING The drawing illustrates a preferred embodiment of a device according to this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS According to a preferred embodiment of this invention, one or several rotating burning disk electrodes which are resistant to aluminum, are applied to the metal layer. It is advantageous to use slowly rotating burning disks with a joint axis, if several disks are applied.
The axis of the disk or disks are not springingly mounted, but the foil contacting the burning disk is maintained in a constant mechanic tension and is 6 pressed against the burning disks. It IS easy to construct such a device since the foils are elastic and provide a good contact with the burning disks. In an advantageous manner, the contacting part o'f th'e burning disks is made of boron nitride or titanium diboride;
It is possible to control the contact pressure by providing means for adjusting the axes of the disk or disks and guide rollers with respect to one another.
According to an advantageous embodiment of this invention, depositions of metal and oxides upon the burning disks are removed by a rotating brush, for instance a steel wire brush. This should be done continuously, and the speed of rotation of the burning disks is adjusted such that a good contact with the metal layer is obtained, along with a complete removal of the deposition.
Referring to the drawing, an insulator foil 1, provided with a metal layer 2 moves via the guide rollers 3 and 4 and is pressed by them against the burning disk electrode 5 which rotates slowly in the arrow direction A. The voltage contact 6 connects the burning disk 5 with a voltage source, supplying a high-frequency alternate voltage or pulsing direct voltage with a minimum frequency of kHz (100,000 cycles/second).
Depositions of metal or metal oxide upon the burning disk 5 are removed by the brush 7 which rotates in the direction B, opposite to the moving direction of the burning disk at the contact point.
The foil itself moves in the direction C which is also the opposite to the moving direction of the burning disk at the corresponding contact point.
It will be apparent from the above description of the preferred embodiments that this invention provides a simple, practical and effective method and device for burning narrow paths into metal layers disposed upon insulator material foils, while moving them at their high production speeds. Although there may be variations and modifications made by those skilled in the art, it is desired to include them within the scope of the invention as defined in the appended claims.
1. Method for producing free paths in metal layers upon insulator foils, comprising the steps of applying a relatively low voltage of a high frequency to at least one circular-disk electrode to form a capacitive coupling between the electrode and the metal layer, pressing the electrode elastically against the metal layer, between two guide rollers, and
moving the electrode with respect to the metal layer thereby continuously renewing the contact portion of the electrode.
2. A device for producing metal-free strips in metal layers disposed upon insulator foils, comprising:
at least two guide rollers for guiding thereon insulator foil having a metal layer disposed thereon;
at least one rotatable circular disk burning electrode disposed between the two guide rollers in such a position that the metallayer of the insulator foil guided on said guide rollers will be resiliently pressed against said electrode;
said electrode being formed of materials which are resistant to aluminum;
means associated with said rotatable burning electrode for cleaning the contact surface of the electrode.
3. A device in accordance with claim 2 wherein the electrode contact surface is formed of boron nitride.
4. A device in accordance with claim 2, wherein the electrode is moved on a rigid axis.
7. A device in accordance with claim 2 wherein the electrode contact surface is formed of titanium diboride.