JPH0666221B2 - Method for manufacturing ceramic laminate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a method for producing a ceramic laminate by firing a laminated green chip obtained by laminating a plurality of ceramic green sheets, for example, a laminated capacitor or the like. To a method used in the manufacture of ceramic electronic components.

[Conventional technology]

Conventionally, an electronic component using a ceramic laminated body such as a laminated capacitor is obtained by laminating a plurality of ceramic green sheets coated with an internal electrode paste to obtain a laminated green chip, which is pressure-bonded in the thickness direction and then integrated. It was manufactured by firing and then applying an external electrode to the end face of the internal electrode, which is pulled out.

In the above process, as shown in FIG. 3, when the obtained sintered body 11 is angular, that is, the sintered body 1
If the connecting parts 11a of each surface of 1 are angular,
The external electrodes 12 and 13 may be insufficiently applied, and the sintered body 11 may be exposed in the angular portion.

Therefore, conventionally, prior to applying the external electrodes 12 and 13,
The corners of the sintered body were dropped by using a polishing method called so-called barrel processing in which a large number of the sintered bodies 11 were put into the rotating barrel and the rotating barrel was rotated.

[Technical problem to be solved by the invention]

Since a large number of sintered bodies are polished by a rotary barrel, it is possible to remove the angular portions, but chips and cracks tend to occur during barrel processing. As a result, the yield was not sufficient, and a considerable proportion of defective products were generated.

Also, in the case of laminated ceramic green sheets printed with internal electrode paste, such as a laminated capacitor,
Since ceramics and metals having different heat shrinkage rates during sintering are simultaneously sintered, peeling tends to occur on the side surface of the sintered body.

Therefore, it is an object of the present invention to provide a method for manufacturing a ceramic laminate that can reduce the occurrence of defective products due to the barrel processing as described above and that is unlikely to cause side peeling.

[Means for solving technical problems]

The manufacturing method of the present invention comprises a step of preparing a laminated green chip by laminating a plurality of ceramic green sheets, and a step of putting the plurality of laminated green chips together with organic powder and cobblestone in a rotating barrel and rotating the same. And a step of firing the raw chips after taking them out from the rotary barrel.

[Action]

The present invention prevents the occurrence of chipping and cracks by performing barrel processing in the state of soft laminated raw chips prior to sintering, and at the same time, the side surface of the laminated raw chips due to the collision action of the boulders put in the barrel. It is characterized in that it suppresses the occurrence of side surface peeling by pressing.
Furthermore, since the organic powder is put in the rotating barrel together with the cobblestone, the cobblestone is wrapped with the organic powder, and thus the degree of collision of the cobblestone with the laminated raw chips is effectively buffered.

[Explanation of Examples]

An embodiment of the present invention applied to manufacture of a laminated capacitor will be described below.

First, an electrode paste for forming internal electrodes is applied on a plurality of ceramic green sheets, the internal electrodes are alternately laminated so as to be drawn out to different end faces of the laminated body, and further pressure-bonded in the thickness direction. , Obtain laminated raw chips. The step of obtaining this laminated green chip can be performed by a well-known method used in manufacturing a conventional laminated capacitor.

Next, a large number of the obtained laminated raw chips were prepared as shown in FIGS.
It is put into the rotating barrel 1 shown in the figure. The rotating barrel 1
As shown in FIG. 2, it has a substantially cylindrical shape, and is made of a material such as a fluororesin that is flexible and hard to adhere to other materials.

Inside the rotating barrel 1, as shown in FIG.
And potato starch powder 3 is added as an organic powder. In this state, a large number of laminated raw chips are put into the rotary barrel 1 and rotationally driven in the arrow direction.

Along with the rotational driving, the cobbles collide with the laminated raw chips, or the laminated raw chips collide with each other. By repeating such collisions, the corners of the angular portion of the outer surface of the laminated raw chip are dropped. Since the corners are dropped in the state of soft raw chips, the corners are dropped in an extremely short time compared to the conventional method.

Moreover, since the boulders 2 are wrapped with the potato starch powder 3, such a collision action is moderately moderated. That is, the collision is not too strong and chipping does not occur. Further, when the boulders 2 collide with each other, the surface of the laminated raw chips is often darkened, but when the boulders 2 are wrapped with the starch starch 3, this darkening is also prevented. Furthermore, since the scraps of the laminated raw chips are also wrapped with the potato starch powder 3, reattachment to the laminated raw chips can be prevented.

In addition, the relatively heavy cobblestone 2 repeatedly collides with the laminated raw chips, so that the outer surface of the laminated raw chips is compacted by the collision. Therefore, the side surface of the laminated green chip, that is, the surface where the laminated surface of the ceramic green sheet is exposed is also pressed, and the density in the vicinity of the side surface is effectively increased.

Next, the barrel 1 is stopped, the laminated raw chips (not shown) whose corners have been dropped are taken out from the barrel 1, and firing is performed. After that, an external electrode is applied to a portion of the obtained sintered body where the internal electrode is drawn out. Sintering and application of external electrodes
It can be performed by a known method conventionally used for manufacturing a multilayer capacitor.

Next, more specific experimental results will be described.

As the rotating barrel 1, a flexible inner volume of 500 ml made of tetrafluoroethylene resin is used, and as the cobblestone 2 a silicon carbide having a diameter of 3 mm to 10 mm as a main component is used, and the barrel 1 has 150 to 200 ml. It was added so as to occupy a certain volume, and 100 ml of potato starch was added as the organic powder 3. A large number of laminated raw chips were placed in the rotating barrel 1 and the barrel was rotated. Thereafter, the laminated green chip was taken out from the rotary barrel and fired to obtain a sintered body.

When the barrel treatment was carried out at various rotation speeds and rotation times, side peeling was most unlikely to occur and optimum results were obtained under the conditions of a rotation speed of 250 rpm and 5 minutes.

In addition, in the above-mentioned example, the starch powder was used as the organic powder 3, but the starch powder is preferable because it does not stick so much, but the organic powder other than the starch powder is not limited as long as it is an organic powder that burns and scatters during firing. It is also possible to use.

Further, the size of the cobblestone 2 and the amount of the cobblestone 2 and the organic powder 3 to be charged into the barrel are different depending on the shape and the number of the stacked raw chips, and thus the above 3 to 10 mm.
It should be pointed out that the diameter and the numerical values of 150 to 200 ml and 100 ml are not limited.

Furthermore, in the above-mentioned embodiment, the one applied to the manufacturing method of the multilayer capacitor has been described, but the present invention can be applied to the general manufacturing of ceramic multilayer electronic components other than the multilayer capacitor, and the formation of the internal electrode is also possible. It can also be used for manufacturing an integrally fired laminate.

〔The invention's effect〕

As described above, according to the present invention, chamfering is performed by the rotating barrel process in the state of the laminated raw chips. Therefore, the chips can be chamfered in an extremely short time as compared with the conventional example in which the sintered body is barrel-processed. Not only that, but also because the chamfering is not performed in the state of a brittle sintered body, the occurrence of chipping, cracks, etc. can be effectively prevented.

Furthermore, in the present invention, since the cobblestone and the organic powder are put into the barrel, the density of the outer surface of the laminated raw chip is increased by the collision of the cobblestone, and as a result, the occurrence of side flaking during sintering is effective. Can be prevented. Also, the impact of the cobblestones is effectively buffered by the organic powder. Not only that, since the scraps of the laminated raw chips are wrapped by the organic powder, it is possible to keep the chip surface clean.

Therefore, according to the present invention, it is possible to effectively improve the yield of a ceramic multilayer electronic component such as a multilayer capacitor, and shorten the manufacturing process.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which cobblestone and organic powder are put into a rotary barrel used in the present invention, FIG. 2 is a perspective view of the rotary barrel, and FIG. 3 is a cross-sectional view for explaining problems of the conventional method. It is a figure. In the figure, 1 is a rotating barrel, 2 is a cobblestone, and 3 is a starch starch as an organic powder.

Claims (1)

[Claims] 1. A step of laminating a plurality of ceramic green sheets to prepare a laminated green chip, and a step of putting a plurality of the laminated green chips together with cobblestone and organic powder in a rotary barrel and rotating the same. And a step of firing the laminated green chip after taking it out from the rotary barrel.