JPS6223446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electrode for etching an electrolytic foil for an electrolytic capacitor.

[Technical background of the invention and its problems] Conventionally, etching of electrolytic foil for electrolytic capacitors has been carried out as shown in FIG. That is, a pair of carbon electrodes 1 having a rectangular shape slightly smaller in width than the electrolytic foil are provided in an etching bath so as to face each other, and masks are provided on both sides of each carbon electrode 1 to protrude toward the other carbon electrode. 2 will be provided. The mask 2 is provided with gas vent holes 3. A stepped portion 4 is formed on the inner edge of the mask 2 in the upper part of the figure on the surface facing the lower mask 2. The aluminum foil 5 travels between the two electrodes 1 with its both side edges engaged with the stepped portion 4. Then, each terminal of the AC power supply is connected to both carbon electrodes 1, or one terminal is connected to both carbon electrodes 1, and the other terminal is connected to aluminum foil 5, and etching is performed.
Gas generated during this etching is released to the outside through the gas vent hole 3 and diffused into the etching solution. When each terminal of an AC power supply is connected to both electrodes 1, the current flowing between the electrodes passes through the gas vent hole 3, so the current efficiency decreases, and the etching magnification decreases toward the edges of the aluminum foil 5. This is a cause of increased variation. Furthermore, the same problem as described above occurs when terminals of an AC power source are connected to the aluminum foil 5 and both electrodes 1, respectively.

[Object of the Invention] The present invention has been made based on the above circumstances, and provides an electrolytic foil for electrolytic capacitors that can improve the current efficiency of etching current during etching and further reduce variations in the etching magnification of the etched foil. The purpose is to obtain an electrode for etching.

[Summary of the Invention] The etching electrode of the electrolytic foil for an electrolytic capacitor of the present invention comprises a pair of carbon electrodes disposed facing each other, and a pair of carbon electrodes disposed on both sides of the carbon electrodes on a plane passing through the center thereof. and a pair of masks having grooves on mutually opposing surfaces that engage with both side edges of the aluminum foil at positions where they intersect with the plane.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1, in which the same parts as in FIG. , are provided at positions where a plane passing through the center of the carbon electrodes 1, 1 intersects with the wall surface 6. The mask 2 has a rectangular cross section, and grooves 7 are provided on the mutually opposing surfaces at positions where planes passing through the centers of the carbon electrodes 1 intersect.

In the etching electrode of the present invention having the above structure, the aluminum foil 5 travels with its edge engaged with the groove 7 of the mask 2. Therefore, the aluminum foil 5 itself acts as an electrical resistor, and the applied current flows from each electrode 1 through the aluminum foil 5 to the opposing electrode. Therefore, current efficiency is improved.

Note that in this embodiment, the corner portions of the mask act as resistance to the current flowing into the aluminum foil 5, and the edges of the aluminum foil 5 may not be etched uniformly. This is an example shown.

In this embodiment, the closer the mask 2 is to the groove 7, the more
Its cross section is determined to be thin. The illustrated cross section is an isosceles triangle. If such a mask 2 is used, the resistance of the mask 2 to the current flowing into the aluminum foil 5 will be significantly reduced.
The aluminum foil 5 is etched almost uniformly to the edges. In any of the above embodiments, the width of the carbon electrode 1 is determined in accordance with the width of the aluminum foil 5. Further, the width of the mask 2, that is, the depth of the groove 7, is determined by adding to the dimension to be masked a deviation due to meandering during travel based on distortion of the aluminum foil 5. Also, groove 7
The width of is within a range that allows continuous running of the aluminum foil 5,
It is better to be as narrow as possible.

FIG. 3A is a diagram showing the distribution of etching magnification in the width direction of etched foil etched with a conventional electrode, and FIG. 3B is a similar diagram according to the embodiment of FIG.
Figure C is a similar diagram when the same mask as in Figure 1 is used and the width of the etching electrode is made smaller than the width of the aluminum foil as in the embodiment in Figure 2, and Figure D is the same as in Figure 2. Similar figures according to the examples show that aluminum foil can be etched almost uniformly by use of the electrodes of the present invention.

[Effects of the Invention] As described above, by using the etching electrode of the present invention, aluminum foil can be etched almost uniformly, so that an electrolytic capacitor of excellent quality can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a sectional view of another embodiment, and FIGS. 3A to 3D are distributions of etching magnification in the foil width direction of etched foil using conventional etching electrodes. FIG. 4 is a cross-sectional view of a conventional etching electrode. 1... Carbon electrode, 2... Mask, 5... Aluminum foil, 7... Groove.

Claims (1)

[Claims] 1 A pair of carbon electrodes arranged facing each other, aluminum foils placed on both sides of the carbon electrodes on a plane passing through their centers, and aluminum foils placed on the mutually opposing surfaces at positions where they intersect with the plane. 1. An electrode for etching an electrolytic foil of an electrolytic capacitor, comprising a pair of masks having grooves that engage with both side edges of the electrode.