JPS6395904A - Method and device for forming ceramic sheet kerf - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for forming cutting grooves on the surface of an unfired ceramic sheet in the production of chip-shaped ceramic resistors, etc., and a method for carrying out the method. Relating to a device for

[Conventional technology]

Conventionally, cutting grooves formed on the surface of an unfired ceramic sheet a have been formed using a press device as shown in FIG. That is, a lower mold 1 with protruding cutting edges 2° 2- arranged in parallel at regular intervals as shown in FIG. 10 is placed on the lower side, and an unfired mold A ceramic sheet a is introduced, and an upper mold 3 is pressed against the ceramic sheet a by means such as a crank press mechanism 4, and a parallel cut groove is formed on the side of the sheet a that is in contact with the lower mold 1.
This is a method of forming b, -.

After repeating this method twice by changing the direction of the ceramic sheet a by 90 degrees and forming grid-like grooves b- on the surface of the same sheet a, as shown in FIG. Screen print conductive paste C. Next, after firing this, the ceramic sheet a is cut into the above-mentioned grooves,
Fold along line b- to cut. by this,
A fine rectangular chip resistor is created.

[Problem that the invention seeks to solve]

However, the conventional kerf forming method and apparatus described above have the following problems.

When the ceramic sheet a is pushed into the cutting edge 2.2-,
The cutting edge 2.2- attempts to break through the surface of the ceramic sheet a at once and bite into it. Therefore, the surface of the ceramic sheet a is drawn inward, and the edges of the kerfs b- become rounded, as shown in FIG.

In the printing process of the conductor paste c, the conductor paste C is not applied to the edge portion of the rounded groove b-. Therefore, the total length of the ceramic chip 11 after cutting is calculated.

If the length of the printable portion of the conductor base lc is taken as 1, the value of 1/L must be small.

In other words, the area on which the conductor base (c) can be printed on the chip, that is, the effective printing area, is narrower than the total projected area of the chip.

In addition, since the kerf b- is formed by applying an impact, fine cracks d as shown in Fig. 11 are likely to occur in the kerf b- part, making the direction of cracking and the fracture surface irregular. It has the disadvantage of being easy.

The present invention has been made to solve the above-mentioned problems in the conventional kerf forming method and apparatus.

[Means to solve the problem]

The structure of the present invention will be explained with reference to the reference numerals in FIGS. 1 to 5. First, the kerf forming method according to the first invention involves applying one main surface of the ceramic sheet a to the hard holding surface 27. The cutting edges 19a, 19a of cutters 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, and 19 are made to cut into the ceramic sheet A from a shallow position to a gradually deeper position. This is a method of forming grooves b- in the ceramic sheet a.

Next, a second invention relating to an apparatus for carrying out the above method will be described.

A member for holding the ceramic seam 1-a having a hard holding surface 27, and a cutter 19 disposed opposite to the holding surface 27.
Equipped with. The cutter 19 has a cutting edge 19a formed with a contour whose distance from the holding surface 27 gradually and continuously changes from a part wider than the thickness of the ceramic sheet a to a part narrower. Also.

The cutter 19 and the ceramic sheet a are connected to the cutting edge 19a.
A feeding mechanism is provided that moves relatively in a direction along.

[For production]

In the above-mentioned kerf forming method and device, the cutting edge 19 of the cutter 19 is
Since a first makes a shallow cut into the surface of the ceramic sheet a, and then gradually makes a deeper cut, the edge of the cutting groove b- is pulled inward, as in the case where the cutting edge 19a breaks through the surface of the ceramic sheet a all at once. Phenomena such as falling are less likely to occur. Therefore, as shown in FIG. 8, the edge of the groove b- has a monogonal cross section even when viewed microscopically, and the conductive paste C or the like can be applied to the very edge.

〔Example〕

Next, an embodiment of the present invention will be described with reference to one drawing.

First, an embodiment of the apparatus of the second invention for forming one cut groove will be described with reference to FIGS. 1 to 4. As shown in FIG.
2.22 are erected, and bearings ii and ii are fixed at positions corresponding to each other.

Both ends of a shaft 13 of the base roller 12 are rotatably supported by this bearing 11.11, and a handle 23 is attached to one end of the shaft 16. This base roller 1
2 has a relatively large diameter and a smooth circumferential surface, and the circumferential surface serves as a holding surface 27 that holds the ceramic sheet a on one main surface. The illustrated base roller 12
is rotated by operating the handle 23, but a motor or the like may also be used as the driving source.

Above the bearings 11 and 11, there is another set of bearings 14°1.
4 are arranged so as to be movable up and down. In the illustrated embodiment,
A bearing 14.14 is fixed to a hair ring holder 24.24 arranged to be movable up and down along the side plate 22.22, and moves up and down the side plate 22.22 as the holder 24.24 moves up and down. Furthermore, an inter-axis adjustment mechanism 17.17 such as a micrometer head fixed to the side plate 22.22 is connected to the bearing holder 22.22.
．． The vertical position of the side plates 22 and 22 of No. 14 can be adjusted thereby.

The shaft 16 of the rotary cutter 15 is attached to the bearing 14.14.
Both ends are rotatably supported. As shown in FIG. 2, this rotary cutter 15 includes a spacer 18 having a uniform diameter in the thickness direction. Between I8-.

A thin disk-shaped cutter 19.1 with larger diameter cutting edges 19a and 19a- than this! J- are sandwiched alternately and fixed to the shaft 16. As shown in Fig. 3 and 4, as shown in Fig. 3 and 4, the cutter 19.19----- 19a, 19, 19a, 19, 19, 19a, 19, 19A, 19a, 19a.
a- stands out.

Both sides of the spacers 1B, I8- and the cutters 19.19- are sandwiched between side plates 25.25 having a larger diameter than the cutters 19.19-, and nuts 26.25 screwed into male threads cut into the shaft 16. 26.

Therefore, by removing this nut 26.26 from the shaft 16, the spacer 18.18- and the cutter 19.1
9- are separated. The inner dimension between the side plates 25 and 25 is set to be slightly wider than the width of the base roller 12.

Cutter 19.19-・Spacer 18.18 from both sides
Since it is strongly sandwiched between -, it is possible to use a fairly thin one. For example, if general cemented carbide is used and the cross section of the cutting edge is made to have a sharp V-shape as shown in Figure 3, a material with a thickness of about 0.1 to 0.3 m1 can be used. .

Next, an embodiment of the method of forming a kerf according to the first invention using this device will be described. First, the distance between the base roller 12 and the rotary cutter 15 is adjusted by the inter-axis adjustment mechanism 17.17. Adjust and cutter 19.19-
The minimum distance from the cutting edge of the base roller 12 to the circumferential surface of the base roller 12 is appropriately adjusted within the range of the thickness of the ceramic sheet a. At the same time, the cutting edges 19a, 19a- of all cutters 19, 19-
Adjustments are made so that the minimum distances are all equal distances from the circumferential surface of the base roller 12. Further, the base roller 12 is sandwiched between the side plates 25 and 25 on both sides of the rotary cutter 15 so that the side surfaces of the base roller 12 are in contact with each other.

In this state, while rotating the base roller 12, one main surface of the unfired ceramic sheet a is placed on its holding surface 27, and the ceramic sheet a is fed between the rotary cutter 15 and the base roller 12. go. By doing this.

As is clear from Fig. 4, the cutting edge 19 has a circular outline.
a, 19a- is first cut into the surface of the ceramic sheet a from a shallow position, and then gradually cut deeper, and the cutting depth is reached at the point where the distance between the holding surface 27 and the cutting edge 19a, 19a- is the narrowest. Maximum. Subsequently, the cutting edges 19a, 1.9a- are gradually removed from the ceramic sheet a. In this way, grooves are cut on the surface of the ceramic sheet a.
b- is inserted.

At the same time, the inner surface of the side plate 25.degree. 25 of the rotary cutter 15 engages with the side surface of the base roller 12, so that the ceramic sheet a is cut into the same width y' as that of the base roller 12.

In the above embodiment, the base roller 12 side is driven as shown by the arrow in FIG. 4, and the rotary cutter 15 is driven by this.

Both can also be driven together. In this case, holding surface 2
7 and the speed of the cutting edges 19a, 19a- can be made equal,
It can also be made different.

Use a cutter made of carbide with a thickness of 0.3mm as the cutter 19.19-, with the cutting edges 19a and 19a- having a V-shaped cross section, and actually cut the groove using the above method. - was formed and when its cross section was observed under magnification, as shown in Fig. 8, there was almost no roundness of the edges like b-, which was formed using a conventional press machine. An extremely thin kerf, b-, was formed. For this reason, the value of l/L in Fig. 8 is thicker (1,7 mm vertically) compared to the conventional crank press method in which grooves and b- are formed.
43 ya*, width 0.944mm, thickness 0.5911
With this ceramic chip, an effective printing area that was more than 20% larger than that of the conventional chip was obtained.

In the embodiment shown in FIG. 5, the holding surface 27 is a circumferential surface, and the linear cutting edge 19a of the cutter 19, which is oriented perpendicularly to the central axis of the base roller 12, is placed close to the holding surface 27. This is what was placed.

In this embodiment, one main surface of the ceramic seam 1-a is held against the holding surface 27, and by moving the holding surface 27 in the direction of the arrow, a cutter 19 forms a groove on the other main surface. do. In this way, if the holding surface 27a is a circumferential surface, even if the cutting edge 19a is straight, it is possible to make the cutting edge 19a gradually cut deeper into the surface of the ceramic sheet a from a shallow position. be.

Next, in the embodiments of FIGS. 6 and 7, the ceramic sheet a
Separately from the base roller 12 for feeding, a fixed base 2 having a fixed flat holding surface 27 is provided, and the cutter 19 is disposed on this fixed base. In FIG. 6, a disk-shaped cutter 19 that can freely rotate twice is used, and in FIG. 7, a holding surface 2 is used.
A fixed cutter 19 is used in which the height of the cutting edge 19a from 7 is gradually lowered. In either case, as the ceramic sheet a is fed, the cutting edge 19a can be made to cut gradually deeper into the surface of the ceramic sheet a.

〔Effect of the invention〕

As explained above, according to the kerf forming method and device according to the present invention, the cutting edges 19a, 19a of the cutter 19, 19-
This is because the surface of the unfired ceramic sheet a is not pushed and cut all at once, but is cut gradually deeper from a shallow position.

There is almost no retraction of the surface into the interior, and the edges can form a square kerf. This makes it possible to increase the effective printing area.

In addition, since the cutting is performed without applying an impact, the ceramic sheet a is less likely to crack, and is less likely to break irregularly during cutting, ensuring a generally constant breakability.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a kerf forming device showing an embodiment of the second invention, and FIG. 2 is a partially cutaway front view. FIG. 3 is an exploded perspective view showing the main parts of the device, FIG. 5 to 7 are longitudinal sectional side views showing the cutting state of the cutting edge of the cutter into the ceramic sheet according to another embodiment;
FIG. 8 is a cross-sectional view illustrating a state in which conductive paste is applied to the surface of a ceramic sheet with grooves formed by the method of the second invention, and FIG. 9 is a part showing a conventional example of a groove forming device. A cutaway side view. FIG. 10 is a cross-sectional view showing the cutting state made by the same device, and FIG. 11 is a cross-sectional view showing the state in which a conductive paste is applied to the surface of a ceramic sheet in which grooves have been cut by the same device.

Claims (1)

[Claims] 1. Cut grooves b, b-- in an unfired ceramic sheet a.
---, one main surface of a ceramic sheet a is held against a hard holding surface 27, and cutters 19, 19 are placed on the other main surface side of the ceramic sheet a.
---- Cutting edges 19a, 19a of ceramic sheet a
A method for forming grooves in a ceramic sheet, characterized by cutting from a shallow position to a gradually deeper position. 2. Cut grooves b, b-- in the unfired ceramic sheet a
--- In an apparatus for forming a ceramic sheet a, a member for holding a ceramic sheet a having a hard holding surface 27;
The cutter 19 has a cutting edge 19a formed with a contour in which the distance from the holding surface 27 gradually and continuously changes from a part wider than the thickness of the ceramic sheet a to a part narrower. A ceramic sheet kerf forming device characterized in that it is further equipped with a feeding mechanism that relatively moves the ceramic sheet a and the cutter 19 in a direction along the cutting edge 19a.