JPH1012502A - Method for manufacturing pellet for solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a method for manufacturing a pellet for a solid electrolytic capacitor, having a penetrating anode lead-out line for better productivity and workability. SOLUTION: A mold 4 is provided with two opposed horizontal punches 3 which are movable in a horizontal direction. In a cavity 5 of the mold 4, a penetrating anode lead-out line 1 is held by an extruder 9 provided in a vertical direction, so that it may protrude to the level of the top of the mold 4. Metallic powder 6, acting as a valve, is charged into the cavity 5 and compressed by the two oppositely located horizontal punches 3 toward the central line to form a pellet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a pellet having a structure having an anode lead-out wire penetrating a pellet of a solid electrolytic capacitor using metal powder having a valve action.

[0002]

2. Description of the Related Art In a conventional solid electrolytic capacitor pellet, a metal powder 6 having a valve action is filled in a cavity 23 formed by a lower punch 21 and a die 22 as shown in FIG. The upper punch 25 is fitted along the die 22 into the cavity 23 with the anode lead-out wire 26 protruding from the lower part 25A of the slab, and the anode lead-out wire 26 is implanted in the metal powder 6 having a valve action. It is compressed and formed into pellets. However, according to this method, only a pellet having a shape in which the anode lead-out wire 26 was led out in one direction as shown in FIG. 5 was obtained. Until now, the pellets 2 of most solid electrolytic capacitors have been shaped as shown in FIG.

[0003] There are two known methods for manufacturing a pellet 2 having an anode lead wire 1 penetrating the pellet 2 as shown in FIG. One of them is as shown in FIG. 6, after the anode lead wire 1 penetrating from the lower punch 21 is projected into the cavity 23, the metal powder 6 having a valve action is filled in the cavity 23, and the anode The lead-out wire 1 is inserted into the center hole 24 of the upper punch 25, the upper punch 25 is fitted into the cavity 23, and the metal powder 6 having a valve action is compression-molded to form a pellet 2 as shown in FIG.
Is produced with the anode lead-out wire 1 penetrating through.

[0004] As another method, as described above, the pellet 2 having the tip of the anode lead wire 26 exposed at one side as shown in FIG.
There is a method in which the anode wire 27 is butt-welded to the tip of the exposed anode lead wire 26 to obtain a pellet 2 having a shape in which the anode lead wire 26 penetrates the pellet 2 apparently.

[0005]

In recent years, in electronic equipment such as information communication equipment, the use of high-frequency electronic circuits has been rapidly expanding in response to miniaturization of equipment, high-speed information processing, digitization, and the like. Accordingly, solid electrolytic capacitors have also been required to be small, light, and compatible with high frequencies in accordance with the above requirements. However, due to its structure, the solid electrolytic capacitor has a large anode internal resistance and cannot be used in a specification corresponding to a high frequency. As one method of manufacturing a solid electrolytic capacitor having good high frequency characteristics by reducing the internal resistance of the anode, a pellet 2 having an anode lead wire 1 penetrating the pellet 2 as shown in FIG. 2 has been required.

As described above, as a method of manufacturing the pellet 2 having the anode lead wire 1 penetrating the pellet, the anode lead wire 1 penetrating from the lower punch 21 is inserted into the cavity 23 by using a mold as shown in FIG. The cavity 23 is filled with metal powder 6 having a valve action, and the penetrating anode lead wire 1 is inserted into the center hole 24 of the upper punch 25.
The upper punch 25 is inserted into the cavity 23 by inserting the metal powder 6 into a metal powder 6 having a valve action.
A method of obtaining the pellet 2 as shown in FIG. 4 and a method of forming a pellet 2 in which the tip of the anode lead wire 26 is exposed to one side as shown in FIG. Are known in which an anode wire 26 is butt-welded 27 to the tip end of the wire.

However, in the above method, as shown in FIG. 6, a method of compression-molding a metal powder having a valve action through the anode lead wire 1 penetrating the upper punch 25 and the lower punch 21 is not used. Anode lead wire 1 penetrating through hole 24
And the upper punch 25 must be fitted into the cavity 23 at the same time as the passage, and the workability is extremely poor. In addition, the method described above uses a diameter of 1 as shown in FIG.
Anode lead wire 26 mm or less is butt-welded to anode wire 27
8, there is a problem in the reliability of welding.

[0008]

In order to solve the above-mentioned problems, as shown in FIG. 1, the flow line of the horizontal pressing punch 3 for compressing the powder in the cavity 5 and the direction of the anode lead wire 1 penetrating therethrough are perpendicular to each other. The structure of the mold body 4 is as follows. That is, the anode lead-out wire 1 penetrating in a direction perpendicular to the center line of the laterally-pressed punch 3 is projected from the end of the cavity 5 into the cavity 5 of the mold body 4 including two opposed laterally-pressed punches 3. I do.

Next, after filling the cavity 5 with the metal powder 6 having a valve action up to the upper portion of the mold body 4, the purpose is to prevent the metal powder 6 having the valve action from overflowing from the upper portion of the mold body 4. The abutment 7 is moved to the upper part of the mold body 4 for the two purposes of fixing the anode lead wire 1 to the center position of the pellet 2. Next, after the metal 7 is pressed from above by the upper punch 8, 2
The opposing side-pressing punches 3 are moved inward to compression-mold metal powder 6 having a valve action.

Next, the upper punch 8, the abutment 7, and the laterally-pushed punch 3 are sequentially moved, and the extruding body 9 is pushed up to take out the molded body from the cavity 5, and then the anode lead-out wire 1 penetrating therethrough.
Is cut into a predetermined length to obtain a pellet 2. As shown in FIG. 2, the pellets 2 thus formed have high reliability because there is no welded portion, and the workability is good, so that the number of steps is greatly reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described by taking a chip type tantalum solid electrolytic capacitor as an example. As shown in FIG. 1, the die body 4 is 1.7 mm wide and 1.1 mm deep by the left and right lateral pressing punches 3.
A cavity 5 having a diameter of 5 mm and a punch distance of 5 mm is provided. Next, a penetrating anode lead wire 1 made of a tantalum wire having a diameter of 0.25 mm 1
Is inserted into the cavity 5 through the central shaft hole of the extrusion body 9 used for extruding the molded body until it coincides with the upper surface 10 of the mold body.

Next, a metal powder 6 having a valve action by a scraping method is placed in a cavity 5 in which the anode lead wire 1 penetrating is installed.
After filling about 13.5 mg of (tantalum metal powder), the penetrating anode lead wire 1 is projected 2 mm from the upper surface 10 of the mold body. Next, the metal 7 is placed so as to sandwich the protruding portion of the anode lead-out wire 1 penetrating while being rubbed with the upper surface 10 of the mold body. Next, while pressing the abutment 7 with the upper punch 8, the left and right laterally-pressed punches 3 are compressed inward with the same force until the distance between the leading ends of the laterally-pressed punches 3 becomes 1.1 mm.

After the metal powder (tantalum metal fine powder) 6 having a valve action is compressed by the left and right lateral pushing punches 3, the upper punch 8, the abutment 7, and the left and right lateral pushing punches 3 are sequentially retracted, and the extrusion body 9 is pressed. , And the molded body is taken out of the cavity 5, and the penetrating anode lead wire 1 is cut into a predetermined length to obtain a pellet 2 as shown in FIG.

The molding may be performed using a two-piece mold as follows. As shown in FIG. 3, two cavities 16 having a cross section of 1.1 mm × 1.7 mm and a depth of 5 mm are formed by two lower punches 13 integrated by a die 11 and a lower punch unit 12.
Is provided. Next, a guide groove 15 provided for the purpose of facilitating the removal of the molded body having the anode lead-out wire 1 penetrating the die 11 from the two cavities 16 and regulating the installation position of the anode lead-out wire 1 penetrating therethrough. A penetrating anode lead wire 1 made of a 0.25 mm tantalum wire is provided.

Next, metal powder 6 (tantalum fine powder) having a valve action is scraped into two cavities 16 by abrasion method for about 2 hours.
After filling 7 mg, the distance between the tip of the upper punch and the lower punch is reduced by using two upper punches 18 integrated by the upper punch unit 17 and two lower punches 13 integrated by the lower punch unit 12. Compress with the same force until 1.1 mm. Next, after the end of the compression, the penetrating anode lead wire 1 is cut out of the die 11, and two upper punches 18 integrated by an upper punch unit 17 and a metal 2 integrated by a metal unit 19.
0 are sequentially retracted from the die 11 to the original position.

Next, the two lower punches 13 integrated by the lower punch unit 12 are pushed up to take out two connected molded bodies out of the cavity 14 and to connect the two molded bodies.
The molded body is cut off into pellets 2 as shown in FIG. The pellets 2 formed by the above two methods can be formed without a density unevenness and without crushing of holes on the surface and have sufficiently high pull-out strength of the anode lead-out wire 1 penetrating therethrough. No burrs were observed at the contact portion of the wire 1 with the pellet 2.

[0017]

The present invention is configured as described above.
It has the following unique effects. As in the present invention, by improving the molding die and the manufacturing method, the production time of the pellets can be reduced to half of the conventional one, and the yield of the pellets has been remarkably improved. A solid electrolytic capacitor having a penetrating anode lead wire that has become impractical due to the high price of the product has become commercially available.

[Brief description of the drawings]

FIG. 1 is a perspective view of a molding die of the present invention.

FIG. 2 is a perspective view of a pellet having a penetrating anode lead wire of the present invention.

FIG. 3 is a perspective view of a molding die of the present invention.

FIG. 4 is a sectional view of a conventional molding die.

FIG. 5 is a perspective view of a conventional pellet.

FIG. 6 is a cross-sectional view of a conventional molding die for pellets having a penetrating anode lead-out line.

FIG. 7 is a perspective view of the pellet manufactured in FIG. 4;

FIG. 8 is a perspective view of a conventional pellet having a penetrating anode lead wire.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Anode lead wire penetrating 2 ... Pellet 3 ... Side pushing punch 4 ... Mold main body 5 ... Cavity 6 ... Metal powder having valve action 7 ... Abutment 8 ... Upper punch 9 ... Extruded main body 10 ... Upper surface of mold main body 11: Die 12: Lower punch unit 13: Two lower punches 14
... cavity 15 ... guide groove 16 ... two cavities 17 ... upper punch unit 18 ... two upper punches 19 ... paying unit 20 ... paying 21 ... lower punch 22 ... dice 23 ... cavity 24 ... center hole 25
... upper punch 25A ... upper part of upper punch 26 ... anode lead wire 27 ... anode wire 28 ... butt welding 29 ... mold body 30 ... end face

Claims (2)

[Claims] 1. A method for manufacturing a pellet having a structure having an anode lead-out wire penetrating a pellet of a solid electrolytic capacitor, comprising: a mold body having two opposing side-pressing punches movably mounted in a horizontal direction; In the cavity, a penetrating anode lead wire held by an extruding body provided in a direction perpendicular to the horizontal pressing punch is projected so as to coincide with the upper surface of the mold body, and a valve action is formed in the cavity. After filling the metal powder having, after slidably mounting the abutment on the upper part of the cavity, the lateral pressing punch is compressed toward the center of the cavity to form a pellet, wherein the pellet has a penetrating anode lead-out wire. Manufacturing method. 2. A method of manufacturing a pellet having a structure having an anode lead-out line penetrating a pellet of a solid electrolytic capacitor, comprising: a die having opposed guide grooves; and two lower punches integrated by a lower punch unit; In two cavities of the mold body constituted by the metal unit, the anode lead wire penetrating the guide groove is made to protrude the die from both end faces,
After that, the cavity is filled with metal powder having a valve action, and two upper punches integrated by an upper punch unit are fitted into the two cavities and compressed to form a pellet. For producing a pellet having an anode lead wire.