JPH0361325B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting multilayer ceramic green sheets.

A ceramic green sheet is a flexible sheet obtained by kneading unfired or calcined ceramic powder with an organic solvent as a binder, for example, by extrusion molding.

This ceramic green sheet is used in the field of electronic components, such as multilayer ceramic capacitors, wound type ceramic capacitors, multilayer inductors, and wound type inductors.

As a preferred example for explaining the use of ceramic green sheets, an example of manufacturing a multilayer ceramic capacitor will be described below.

First, prepare a ceramic green sheet molded to a certain size in advance, and place Pt, which will become the internal electrode, on this ceramic green sheet.
A high-melting point conductive paste such as Pd or Pt-Pd is printed, and the ceramic green sheets are laminated so that the internal electrodes appear alternately on the sides of the laminated body. After the laminated body is crimped, it is fired, and then the fired body is This is obtained by forming an external electrode electrically connected to the internal electrode on the side surface.

Since these laminated ceramic capacitors have small individual dimensions, larger ceramic green sheets are used to form a laminate, and before firing, they are cut perpendicular to the main surface of the laminate to a certain size. Things were being done. This cutting process was carried out by warming the laminate in advance and cutting it with a knife.

However, if the temperature at which the laminate is heated is too high, the organic solvent and water contained in the laminate will evaporate, causing layer peeling.
This was a cause of failures due to decreased capacity. On the other hand, if the temperature at which the laminate is heated is low, the laminate cannot be given plasticity, making it difficult to cut.

Therefore, the present invention has been made to solve these problems, and an object of the present invention is to provide a method for cutting a green ceramic laminate that can easily cut a multilayered ceramic green sheet.

Another object of the present invention is to provide a method for cutting a green ceramic laminate that does not cause peeling between ceramic green sheets during cutting.

That is, the gist of the present invention is a method for cutting a green ceramic laminate, which is characterized in that a multilayered ceramic green sheet is cut by a heated blade.

In the present invention, the multilayer ceramic green sheet is not limited to a laminated ceramic green sheet stacked as described in the above-mentioned conventional example, but can also be applied to, for example, a wound ceramic green sheet. be able to.

The present invention will be explained below with reference to an example in which a green ceramic multilayer body made of ceramic green sheets is cut.

Figures 1a and 1b and 2 show an example of obtaining a wound type ceramic capacitor.

In the figure, internal electrodes 3 and 4 are provided on one surface of two ceramic green sheets 1 and 2, respectively.
is formed. The internal electrodes 3 and 4 are formed at different positions so that one side edge appears on the edge of the ceramic green sheets 1 and 2, and the other portions are formed with gaps left.

Ceramic green sheet 1 is attached to the other ceramic green sheet 2 in the same direction as shown in the drawing.
2, and is rolled up around an unfired ceramic core 5, as shown in FIG. The wound laminate is in a state in which internal electrodes 3 and 4 are interposed between ceramic green sheets 1 and 2. Therefore, as shown in FIG. 3, the internal electrode 3 is located at one end of the laminate;
In the illustrated state, it appears on the left edge, and the internal electrode 4 appears on the other end of the stacked body, and in the illustrated state, on the right edge. A laminate having such a structure becomes a sintered body by being subjected to a firing process, and has electrodes 6 on both sides.
By forming 7, a wound type ceramic capacitor can be obtained.

As shown in FIG. 4, such a wound type ceramic capacitor usually uses slightly larger ceramic green sheets 11 and 12, and each ceramic green sheet 11 and 12 has a plurality of internal electrodes 13, 14 are formed respectively.

Therefore, when wound around the ceramic core 15, a single wound type ceramic capacitor including a plurality of capacitors is obtained. Of course, in this state it is unfired and has not been subjected to the firing process.

In order to obtain individual ceramic capacitors, prior to the firing process, cutting is performed at the positions of cutting lines (dotted and dashed lines) A, B, C, and D, as shown in FIG.

In the method of this invention, the blade is heated in advance using a heater or the like, and the wound rod-shaped ceramic capacitor is cut at the positions of cutting lines A, B, C, and D in a direction perpendicular to the axial direction of the wound rod-shaped ceramic capacitor.

The heating temperature of the blade used for cutting may be a temperature sufficient to warm the ceramic green sheet to some extent and plasticize it, for example, at a temperature of 60°C. At this time, the material of the ceramic green sheet, the amount of binder, etc. are taken into consideration.

At the stage of cutting with the blade, the temperature of the blade warms and plasticizes the ceramic green sheet that is in contact with the blade, allowing for smooth cutting. On the other hand, the evaporation of the organic solvent and water contained in the ceramic green sheet is almost non-problematic, and there is no occurrence of layer peeling like in conventional examples, and there is no layer peeling on the cut surface as well. It's nothing to worry about.

The cut multilayer body is subjected to a firing process in the same manner as in the conventional example, and electrodes are further formed on both side edges to obtain a capacitor.

In the above embodiments, a winding type green ceramic laminate was explained, but it goes without saying that the method of the present invention can also be applied to a laminated green ceramic laminate made by stacking ceramic green sheets.

In addition, when heating the blade, the blade may be heated by indirect heat conduction without bringing the heating element into direct contact with the blade, but it is also possible to heat the blade by directly thermally coupling the heating element to the blade. be.

Furthermore, the cutting direction is not limited to the case where the cutting is perpendicular to the main surface of the stacked laminate, and the cutting may be performed in an oblique direction.

As described above, according to the method of the present invention, a multilayered ceramic green sheet is cut by a blade whose temperature has been raised by heating, so the ceramic green sheet is heated by the blade near the cutting position, so that the ceramic green sheet has plasticity. This makes cutting easier. In addition, since the other parts of the ceramic green sheet are not heated, there is no occurrence of layer peeling that occurs when the entire ceramic green sheet is heated, and the problem of reduced capacity can be solved.

[Brief explanation of drawings]

Figures 1a, b, 2, and 3 are diagrams for explaining an example of manufacturing a wound type ceramic capacitor; Figures 1a, b are plan views, and Figure 2 is a perspective view. , FIG. 3 is a longitudinal sectional view. FIGS. 4 and 5 are diagrams for explaining the method of carrying out the present invention, with FIG. 4 being a perspective view and FIG. 5 being a longitudinal sectional view. 11 and 12 are ceramic green sheets, 1
3 and 14 are internal electrodes.

Claims (1)

[Scope of Claims] 1. A method for cutting a green ceramic laminate, which comprises cutting a multilayered ceramic green sheet body using a heated blade. 2. The method for cutting a green ceramic laminate according to claim 1, wherein the multilayered ceramic green sheet body is a laminate of ceramic green sheets. 3. The method for cutting a green ceramic laminate according to claim 1, wherein the multilayer ceramic green sheet body is a ceramic green sheet wound around the body.