JPH074891Y2 - Green sheet forming machine - Google Patents

Description

[Detailed Description of the Invention] [Outline] A green sheet molding machine for forming a ceramic circuit board of a printed board that is widely used in the construction of various electronic devices. For the purpose of forming a small number of green sheets, a means for equalizing the flow rate of the slurry forming the green sheets in a container in which a bottom plate with a slurry outlet is provided with a pair of side walls and a back wall on three sides and one side is open. A liquid tank surrounded by the dam disposed between the both side walls on the open side of the slurry discharge port and the both side walls and the back wall, and the slurry is supplied from the slurry discharge port of the liquid tank. The slurry accumulated in the liquid tank is configured to overflow from the upper end surface of the dam and flow toward the open end of the container.

[Industrial application field]

The present invention relates to a green sheet molding machine for forming a ceramic circuit board of a printed board that is widely used for the construction of various electronic devices.

Recently, various electronic devices are composed of printed circuit boards with high mounting density of electronic components, and the circuit board uses a ceramic substrate with a fine pattern printed.If there is variation in the thickness of the ceramic substrate, pattern printing is possible. There is a need for a green sheet forming machine capable of forming a green sheet having a small variation in thickness in order to exert an adverse effect and reduce the reliability of the entire printed board.

[Conventional technology]

The conventional green sheet forming machine is the 5th
As shown in the figure, a pair of side walls 1-2, each of which is formed with an arc that is in close contact with the outer peripheral surface of the doctor blade 4, are provided in parallel with the bottom plate 1-1 having the slurry discharge ports 1-1a at regular intervals. , A rectangular back wall 1-3 is formed on the slurry discharge port 1-1a side to form a liquid tank 1.

On the other hand, as shown in FIG. 4, the comma roll 6 around which the carrier film 7 is wound and the doctor blade 4 for adjusting the thickness of the green sheet 8 are horizontally opposed to each other so as to have a constant gap, A drying furnace 9 is arranged on the advancing direction side of the green sheet 8. The bottom plate 1-1 is inclined at a certain angle with respect to the horizontal with the arcs of both side walls 1-2 of the liquid tank 1 in close contact with the outer peripheral surface of the doctor blade 4 on the doctor blade 4 inlet side of such a device. Let it stick. A defoaming pump (not shown) is connected to the slurry discharge port 1-1a of the bottom plate 1-1 by a pipe 3, and the slurry 2 is attached to the upper part of the liquid tank 1.
A liquid level sensor 5 is provided to detect the liquid level and control the discharge amount of the slurry 2.

Then, the carrier film 7 is wound around the comma roll 6 facing the doctor blade 4, and the slurry 2 is discharged from the slurry discharge port 1-1a of the liquid tank 1 by the defoaming pump to be placed on the bottom plate 1-1. Carrier film 7 pooled and wound
The doctor blade 4 by moving in the direction of the arrow.
The slurry 2 is caused to flow out from the space between the comma rolls 6 to form the green sheet 8 on the carrier film 7, and the dried green sheet is formed by passing through the drying furnace 9 in this state.

[Problems to be solved by the device]

The problem with the conventional green sheet forming machine described above is that the slurry 2 supplied from one slurry discharge port 1-1a provided in the liquid tank 1 shown in FIG.
As shown in the figure, a mud flow is formed in the mark direction on the bottom plate 1-1 inclined at a constant angle, and the flow is gradually dispersed in the direction indicated by the arrow ↑ as it approaches the doctor blade 4. Therefore, the liquid level in the vicinity of the doctor blade 4 becomes higher in the central part with respect to the side walls 1-2, and the amount of the slurry flowing out from the gap between the doctor blade 4 and the comma roll 6 due to the pressure difference is in the central part. However, there is a problem in that the green sheet dried by passing through the drying oven has a thick central portion and thin side edges, which adversely affects pattern printing.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a new green sheet forming machine capable of forming a green sheet with a uniform thickness flow of a slurry and a small thickness deviation.

[Means for Solving the Problems]

The present invention, as shown in FIG. 1, has a bottom plate 1-1 having a slurry outlet 1-1a, a pair of side walls 1-2 and a rear wall 1-3.
In the same liquid tank as the conventional one formed as described above, as shown in FIG. 2, means for making the flow of the slurry uniform between the side walls 1-2, for example, a width smaller than the height of the side walls 1-2 and facing long sides. Between the side walls 1-2 provided on the bottom plate 1-1 with dams 11-1 and 11-1 'whose one side is corrugated or arc shaped to have a high central part Then, the back wall 1-
3, a liquid tank 11 is formed so that the slurry discharge port 1-1a is located in the center of the liquid tank 11, and a drying furnace 9 shown in FIG. The bottom plate 1-1 is fixed to the side by inclining at a constant angle with respect to the horizontal. Then, the slurry is supplied from the slurry discharge port 1-1a of the liquid tank 11 so that the slurry accumulated in the liquid tank 11 overflows from the upper end surfaces of the dams 11-1 and 11-1 'and flows toward the doctor blade 4. By doing so, a green sheet having a uniform plate thickness is formed.

[Action]

In the present invention, the high-viscosity slurry introduced from the slurry discharge port 1-1a provided at the bottom of the liquid tank 11 is accumulated in the liquid tank 11 and overflows toward the doctor blade 4 from the upper end surface of the dam 11-1. As a result, it is possible to reduce the influence of fluctuations in the supply pressure of the slurry introduced from the slurry discharge port 1-1a provided at the bottom of the liquid tank 11. Also, by making the upper end surface of the dam 11-1 into a corrugated shape or a circular arc shape with a high central portion, the slurry overflowing the dam 11-1 can have a side wall
The flow rate (thickness) in the width direction of the flow between the two becomes almost uniform,
The flow rate of the slurry flowing on the bottom plate 1-1 inclined at a constant angle toward the doctor blade 4 becomes uniform, and the flow rate (thickness) in the width direction of the doctor blade 4 is almost uniform near the inlet of the doctor blade 4. Since the surface (liquid surface) is flat and the thickness of the green sheet formed on the carrier film 7 is also uniform due to the gap between the doctor blade 4 and the comma roll 6, it is possible to make the green sheet plate thickness after drying uniform. Becomes

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view showing a liquid tank of a green sheet forming machine according to this embodiment, and FIG. 2 is a front view of a dam according to this embodiment.
In the figure, the same members as those in FIG. 4 are denoted by the same symbols, but the other 11 is a liquid tank for supplying the slurry to the doctor blade by making the slurry flow rate between both side walls uniform.

As shown in FIG. 1, the liquid tank 11 is a rectangular plate having a width smaller than the heights of the side wall 1-2 and the back wall 1-3 and aligned with the side walls 1-2, and a slurry corrugated at an arbitrary pitch. A means for equalizing the flow rate is formed on one side of the long side of the dam 11-1, or a dam 11-1 'is formed in a shape in which the central part is higher by a certain value than the both ends of the circular arc. The bottom plate 1-1 provided with 1a, a pair of side walls 1-2 and a back wall 1-3, and the same liquid tank as the conventional one, provided on the bottom plate 1-1 with the corrugated or arc side up. Between the side walls 1-2, the rear wall 1-on the doctor blade 4 side from the slurry discharge port 1-1a.
It is arranged so as to be 3.

As shown in FIG. 4, the green sheet forming machine using the above-mentioned members horizontally mounts the comma roll 6 doctor blade 4 facing each other with a constant gap, and installs the drying oven 9 on the advancing direction side of the green sheet 8. The arcs of the side walls 1-2 of the liquid tank 11 are closely attached to the outer peripheral surface of the doctor blade 4 on the inlet side of the doctor blade 4 having the same structure as the conventional one, and the bottom plate 1-1 thereof has a constant horizontal position. Tilt at an angle and fix.

Then, as in the conventional case, the slurry discharge port 1-1a and the defoaming pump are connected by the pipe 3, and the liquid level sensor 5 is attached to the upper part of the liquid tank 1.
Is arranged to form the green sheet 8 on the carrier film 7 and pass through the drying furnace 9 to form the green sheet.

As a result, the slurry discharged from the slurry discharge port 1-1a accumulates between the opposing dam 11-1 and the back wall 1-3, and as a result overflows from the upper end surface of the dam 11-1.
It is possible to reduce the influence of fluctuations in the supply pressure of the slurry introduced from the slurry discharge port 1-1a provided at the bottom of the nozzle 11. In addition, due to the corrugation formed on the upper end surface of the dam 11-1 or the slurry that overflows due to the middle-height shape, the overflowing slurry becomes almost even between the side walls 1-2, and the liquid surface near the doctor blade 4 is a direction orthogonal to the green sheet forming direction Is horizontal, the thickness of the green sheet 8 formed on the carrier film 7 by the doctor blade 4 is also uniform, and the plate thickness after drying can be uniform.

Further, as shown in FIG. 3, a diffusion plate 21-1 is arranged above the slurry discharge port 1-1a of the liquid tank 11 provided with the dam 11-1, and the slurry discharge port 1 is provided by the diffusion plate 21-1. The slurry 2 discharged from the -1a between the dam 11-1 and the back wall 1-3,
The same effect as described above can be obtained in other embodiments in which the flow is evenly divided in the -2 direction.

[Effect of device]

As is apparent from the above description, the present invention provides a green sheet forming machine which has an extremely simple structure and has advantages such as a uniform thickness of the green sheet, and which can be expected to significantly improve reliability. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing a liquid tank of a green sheet forming machine according to an embodiment of the present invention, FIG. 2 is a front view showing a dam of this embodiment, and FIG. 3 is a liquid tank of another embodiment. Fig. 4 is a perspective view, Fig. 4 is a schematic view showing a conventional green sheet forming machine, Fig. 5 is a perspective view showing a conventional liquid tank, and Fig. 6 is a plan view showing the flow of slurry in the liquid tank. In the figure, 1-1 is a bottom plate, 1-1a is a slurry discharge port, 1-2 is a side wall,
1-3 is a back wall, 4 is a doctor blade, 11 and 21 are liquid tanks, 11-1 are dams, 21-1 is a diffusion plate.

Claims (1)

[Scope of utility model registration request] 1. A container in which a bottom plate having a slurry discharge port is provided with walls on three sides by a pair of side walls and a back wall and one of which is open,
A dam disposed between the both side walls on the open side of the slurry discharge port and a liquid tank surrounded by the both side walls and the back wall are provided, and the slurry is supplied from the slurry discharge port of the liquid tank to the liquid tank. A green sheet forming machine, characterized in that the slurry accumulated in the overflows from the upper end surface of the dam to flow toward the open end of the container.