JPH0232774B2 - SEKISOFUIRUMUKONDENSANOSEIZOHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a multilayer film capacitor in which a cutting means for cutting a mother element into unit elements is improved. Generally, a method for manufacturing a laminated film capacitor is known from Japanese Patent Publication No. 1021/1983 or West German Patent No. 176454. In other words, the outline is that a mother element made by winding a pair of metallized films around a large diameter winding core and forming metallicon electrodes on both end faces is removed from said large diameter winding core and cut into the required size in the radial direction with a rotating saw blade. This is a manufacturing method for manufacturing a plurality of unit elements. However, the electrical dielectric strength of the cut surface created by the lever is caused by the metal layer on the film being broken near the cut surface due to the heat and mechanical vibrations generated during cutting with the saw blade. However, it is actually difficult to uniformly heat the cut surface to a constant temperature with a saw blade.
In other words, when using a regular circular saw blade (metal saw, etc.), if the heating is too small, the metal layer will not break sufficiently and the dielectric strength will be low; if the heating is too large, a kind of thermal runaway will occur and the cut surface will become rough, reducing the electrical dielectric strength. decreases rapidly, narrowing the range of cutting conditions.
The reason for this is that it is necessary to uniformly heat the cut surface when cutting, whereas a regular circular saw blade (metal saw, etc.)
Although the sides of the saw blade that come into contact with the cutting surface are designed to reduce friction to prevent burning with metal, they are not suitable for cutting multilayer film capacitors made of plastic.

The present invention has been made in view of the above points, and provides a method for manufacturing a laminated film capacitor in which a cut surface with good electrical insulation voltage can be obtained by using a rotary saw blade with an improved cutting edge shape. The purpose is to

The present invention will be explained below with reference to the drawings. FIG. 1 shows an example of the rotary saw blade 1 used in the present invention.
The figure is an enlarged view of FIG. 1A viewed in the direction of the arrow, and FIG. 3 is an enlarged view of FIG. That is, the rotary saw blade 1 according to the present invention has a shape of the cutting edge 2 that is thicker toward the tip and toward the rotation direction, and due to this shape, the cutting surface is formed on the side surface of the tip of the saw blade 1. It is possible to effectively rub the saw blade, and thermal runaway does not occur even when the saw blade rotates at high speed. In this case, the side angle A in FIGS. 2 and 3 is preferably 0.5° to 2.0°, and the side angle B is preferably 0° to 1.0°. If the side angle A is less than 0.5°, the blade becomes similar to a normal saw blade, and the cutting burr is generated due to high speed rotation, which causes problems in subsequent handling. If it is larger than 2.0°, the friction effect will be reduced and at the same time the width of the blade will increase, resulting in increased cutting loss, which is undesirable, and if the side angle B is larger than 1°, it is also undesirable for the same reasons as mentioned above.

Example 1 Two metallized polyester films (margin width 0.5 mm) with a thickness of 5μ and a width of 8 mm were stacked together as a pair, wound 800 times on a winding drum with a diameter of 1000 mm, and metallicon electrodes were applied to both end surfaces. After being left in a constant temperature bath at 120°C for 15 hours for heat aging, it was removed from the winding drum to obtain a mother element. Then, the mother element is used as a normal metal saw (125mmφ×0.5t×68 blades).
Conventional example X was cut to a width of approximately 10 mm using
1.5°, and the side angle B shown in Fig. 3 was 0°, and the electrical dielectric strength of the cut surface according to the present invention Y, which was cut to a width of about 10 mm, was investigated, and the result was as shown in Fig. 4. Ta. The breakdown voltage in this case was defined as the voltage at which discharge began to occur at the cut surface. As is clear from Fig. 4, the starting voltage of the cutting surface of Conventional Example X is
While it varies from 150V to 500V (DC), the discharge starting voltage of Invention Y is 600 to 850V.
(DC), the variation was small, and the absolute value was high, demonstrating the superiority of the present invention. There were 10 samples for each of X and Y, and the circles indicate the average values.

Example 2 Two metallized polyester films (margin width 0.5 mm) with a thickness of 5 μm and a width of 8 mm were stacked together as a pair and wound 800 times on a winding drum with a diameter of 1000 mm, with metallized electrodes applied to both ends and rolled at an angle of 120°. After heat aging by leaving the sample in a constant temperature bath for 15 hours, the sample was removed from the winding drum to obtain a mother element. However, the mother element was cut into a metal saw (125mmφ) with varying side angles A and B.
Figure 5 shows the results of examining the breakdown voltage of a unit element cut into a width of approximately 10 mm at a saw blade rotation speed of 6000 rpm and a cutting speed of 3.0 mm/sec.
In the figure, a shows the side angle B0°, b shows the side angle 0.5°, c shows the side angle 1.0°, d shows the side angle 1.5°, and e shows the side angle 2.0°.
The breakdown voltage in this case was defined as the voltage at which discharge began to occur at the cut surface. As is clear from Figure 5, it is also possible to use a rotary saw blade with side angle A in the range of 0.5° to 2.0° and side angle B in the range of 0° to 1.0°; It was demonstrated that using a rotating saw blade causes a sudden drop in breakdown voltage, which is undesirable. Ten samples were used for each, and the numerical values are the average values.

In the above embodiment, a so-called metal saw was used as the rotary saw blade, but a tip saw with carbide welded to the cutting edge may also be used.

According to the manufacturing method of the multilayer film capacitor constructed as described above, frictional heat is effectively generated on the side surface of the cutting edge, and the dielectric strength of the cut surface is improved by uniformly heating the cut surface, as well as the effect of improving the dielectric strength of the cut surface. Even when the blade rotates at high speed, thermal runaway does not occur and the range of cutting conditions is expanded to a practically sufficient range. Since high-speed rotation is possible and the amount of cutting can be increased, cutting speed can be increased and efficiency can be significantly improved.

The plastic film melted by the high-speed rotation is scattered and does not stick to the saw blade, so a uniform cut surface can always be obtained and the life of the saw blade can be maintained for a long time. It has many excellent effects such as good friction, no cutting burrs, and no problems in subsequent handling.

As described above, according to the present invention, an excellent cutting surface can be obtained by using a rotary saw blade having an edge shape that has an angle on both sides in the direction toward the tip and on both sides in the direction of rotation. It is possible to efficiently obtain a multilayer film capacitor with

[Brief explanation of drawings]

Figures 1 to 3 relate to the present invention; Figure 1 is a plan view showing a rotary saw blade, Figure 2 is an enlarged view of part A in Figure 1 viewed in the direction of the arrow, and Figure 3 is the bottom view of Figure 1. Fig. 4 is a characteristic diagram showing a comparison of the breakdown voltage of the cut surface of the conventional example and the present invention, and Fig. 5 shows the breakdown voltage as a function of the side angle of the tip of the rotary saw blade. It is a characteristic curve diagram. 1...Rotary saw blade, 2...Blade tip.

Claims (1)

[Scope of Claims] 1. A lamination method in which a pair of metallized films are laminated and wound around a large-diameter winding core, and a mother element with metallized electrodes formed on both end faces is cut in the radial direction using a rotary saw blade to divide it into unit elements. In the method for manufacturing a film capacitor, the saw blade has a cutting edge shape that is thicker toward the tip, with both sides having an angle of 0.5° to 2.0°, and having both sides having an angle of 0° to 1.0° in the direction of rotation. A method for manufacturing a multilayer film capacitor, characterized in that it is made of a multilayer film capacitor having a thickness within a range. 2. The method for manufacturing a multilayer film capacitor according to claim 1, characterized in that a tip saw with carbide welded to the cutting edge is used as the saw blade.