JPH0969472A - Manufacture of pellet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitor which is provided with a wire that is restrained from being bent or broken inside it or a pellet, very stable in characteristics, high in reliability, and enhanced in productivity. SOLUTION: A wire 1 is made to protrude in a cavity 4 made up with a lower punch 2, a die base 8, and a side punch 3 passing through the lower punch 2, and then powder is put into the cavity 4 and compressed by the side punch 3 for the formation of a pellet, wherein cavities are provided on the same plane, and a pallet forming process can be executed through the cavities for the formation of pellets.

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 pellets of a sintered capacitor element.

[0002]

2. Description of the Related Art In a method of manufacturing a sintered capacitor element, a pellet made of a powder compact in which a wire to be an anode is embedded is used. As shown in FIG. 2, the pellets are molded by first filling a molding powder 5 into a cavity 4 formed by a lower punch 2 and a die 6, and then projecting a wire 1 from a lower portion 6A of the upper punch 1A. In this state, the upper punch 6 is fitted into the cavity 4 along the die 7 to be embedded in the powder 5 in the wire and the powder 5 is compressed.

After that, the upper punch 6 is pulled out from the cavity 4 and the wire rod 1 is cut at a predetermined position, and the powder compact having the wire rod 1 embedded therein is discharged out of the die 7 to form pellets. This pellet is heated and sintered in a non-oxidizing atmosphere or vacuum,
It is used as a capacitor element.

[0004]

The powder 5 has a particle size of 0.
001-0.4mm, wire rod 1 has a diameter of 0.15-0.6mm
Are used. When the wire rod 1 is inserted into the powder 5 at the time of pellet molding, the contact resistance between the particles of the powder 5 and the wire rod 1 increases, and the wire rod 1 is less likely to be inserted into the powder 5. Inserting wire 1 and lower punch 2, die base 8
Further, since the powder 5 in the cavity 4 formed by the side punch 3 and the side punch 3 is compressed, the resistance of insertion of the wire 1 into the powder 5 becomes large.

For the above reasons, the wire rod 1 may not be embedded in a predetermined size, may not be inserted sufficiently, or may be bent. For this reason, there are drawbacks that the wire rod 1 is pulled out during the process or when it is used as a capacitor, and the pull-out strength does not reach a predetermined strength, so that the reliability is lowered.

Further, conventionally, a series of operations for independently filling the cavity 4 with the powder 5 and compressing it and taking out the powder compact have been carried out, resulting in poor molding efficiency and a great obstacle to productivity improvement.

[0007]

In order to solve such a problem, the present invention solves the above problems by, as shown in FIG. 3, forming a lower punch 2 in an empty cavity 4 formed by a lower punch 2, a die base 8 and a side punch 3. 1 part of the wire rod 1 protrudes from the upper surface 2A of the
Then, as shown in FIG. 4, the powder 5 is filled in the cavity 4, and then the bottom surface 6A of the upper punch 6 is lowered to the surface 3A of the side punch 3 as shown in FIG. Move the side punch 3 toward the center to move the powder 5
Compress.

After that, as shown in FIG. 5, the pellet 9 in which the wire rod 1 is embedded is pushed up to the outside of the cavity 4 to form the pellet 9
Is held by an arm 10 and the wire 1 is cut into a predetermined size by a cutter 11 to produce a pellet 9.

Further, in order to improve the productivity of the pellets 9, a plurality of independent cavities 4 are installed on the same surface, and the plurality of cavities 4 are filled with the protrusions 1A of the wire 1 and the powder 5.
The compression by the side punch 3 and a large number of the pellets 9 taken out may be simultaneously performed.

[0010]

According to the present invention, as shown in FIG. 1, the wire 4 is first filled on the upper surface of the lower punch 2 without first filling the powder 5 into the cavity 4 formed by the lower punch 2, the die base 8 and the side punch 3. Since the powder 5 is filled after the protrusion 1A from the wire 2A, the contact resistance between the particles of the powder 5 and the wire 1 is small, so that the wire 1 is not embedded in the pellet 9, or the insertion is insufficient, It is possible to manufacture pellets that do not bend and have stable pull-out strength with stability and high reliability, and by installing a plurality of cavities 4 on the same surface, a series of operations up to compression are manufactured simultaneously. Therefore, there is a feature that the productivity is very excellent and the productivity is high.

[0011]

Embodiments of the present invention will be described with reference to the drawings taking tantalum pellets as an example. As shown in Figure 3, 1.0 x 3.5 mm
A cavity 4 made of a lower punch 2, a die base 8 and a side punch 3 having a corner sectional area and a depth of 1.2 mm is used. Diameter 0.25 from the upper surface 2A of the lower punch 2.
The tantalum wire 1 of mm is projected by 0.8 mm by 1 A.

Next, as shown in FIG. 4, the average particle size is 3 μm, 2
The cavities 4 are filled with tantalum powder 5 having a secondary particle size of about 100 μm. Next, as shown in FIG. 1, the bottom surface 6 of the upper punch 6 is
After pressing A until it is bonded to the upper surface 3A of the side punch 3, the side punches 3 are moved toward each other toward the center and the powder 5 is compressed until the inner diameter of the side punch 3 becomes 0.9 mm.

After compression, the upper punch 6 is first pulled up,
The side punches 3 are retreated to the left with respect to each other, and then the upper surface 2A of the lower punch 2 becomes the upper surface 3A of the side punch 3 as shown in FIG.
The lower punch 2 is pushed up until it coincides with, and the pellet 9 is discharged to the outside of the cavity 4.

The tantalum wire 1 is fed by the feed roller 12 to 10 mm.
At the same time as sending out and pushing up the pellet 9, the arm 1
At the same time when the pellet 9 is pushed up by 0, the pellet 9 is held by the arm 10, and then the tantalum wire 1 is cut by the cutter 11.

In order to improve the productivity of the above operation, a plurality of cavities 4 are installed in parallel on the same plane, and the plurality of cavities 4 are provided with a protrusion 1A of the wire rod 1, a powder 5 filled, and a compressed pellet by a side punch 3. It is also possible to take out 9 and cut the tantalum wire 1 at the same time.

[0016]

Since the pellets of the present invention are manufactured as described above, they have the following unique effects. Lower punch 2, die base 8 and side punch 3
After the wire rod 1 is made to protrude from the upper surface 2A of the lower punch by passing the lower punch 2 into the cavity 4 made by, the powder is filled in the cavity 4 and the powder 5 is compressed by the side punches 3, so that the particles of the powder 5 are formed. Since the contact resistance between the wire rod 1 and the wire rod 1 is small, the wire rod 1 is not embedded in the pellet 9, is not inserted sufficiently, or is not bent, and the wire rod 1 is pulled out after sintering. There is no such thing. When the pull-out strength layers of the wire rod 1 from the pellet 9 of the present invention product and the conventional product are compared with each other for 500 samples, it is 4
Although the individual pieces were pulled out, the product of the present invention was not pulled out. By arranging the cavities 4 in parallel on the same plane, the working time for manufacturing the pellets 9 could be shortened to 1/3 of the conventional time.

[Brief description of drawings]

FIG. 1 shows a sectional view of the present invention.

FIG. 2 shows a conventional sectional view.

FIG. 3 shows a sectional view of the present invention.

FIG. 4 shows a cross-sectional view of the present invention.

FIG. 5 shows a cross-sectional view of the present invention.

[Explanation of symbols]

1 ... Wire rod, 1A ... Projection, 2 ... Lower punch, 2A ... Lower punch upper surface, 3 ... Side punch, 3A ... Side punch upper surface, 4 ... Cavity, 5 ... Powder, 6 ... Upper punch,
6A ... Upper punch bottom surface, 7 ... Die, 8 ... Die base, 9 ... Pellet, 10 ... Arm, 11 ... Cutter

Claims (2)

[Claims] 1. A pellet manufacturing method for producing pellets in which wire rods are embedded, wherein a wire rod is projected from an upper surface of the lower punch into a cavity formed by a lower punch side punch and a die base. A method for producing pellets, comprising filling powder, and then pressing down the bottom surface of the upper punch until it joins the upper surface of the side punch, and then moving the side punches toward each other toward the center to compress the powder. 2. The pellet according to claim 1, wherein cavities formed by a plurality of independent lower punches and side punches are provided on the same plane, and a plurality of side punches belonging to the plurality of cavities are simultaneously compressed and a plurality of pellets are simultaneously pelletized. A method for producing pellets, comprising: