JPH0480001A - Slurry supply method - Google Patents

Abstract

PURPOSE:To keep the thickness of a green sheet constant by detecting the fluctuation of the liquid surface of the slurry in a slurry dam to simultaneously increase and decrease the feed pressure of the slurry and the thickness of a slurry supply pipe. CONSTITUTION:The slurry 2 received in a slurry tank 1 is pressurized by nitrogen gas 3 to be fed to a slurry dam 5 under pressure through a slurry supply pipe 11 and a definite amount of the slurry is accumulated to be molded into a green sheet through a doctor blade 6 and a back roll 7. At this time, a silicone tube is used as the slurry supply pipe 11 and an air actuator 12 is provided to the almost intermediate part of the pipe 11 and a partition member 13 is provided in the slurry dam 5. The liquid surface of the slurry in the slurry dam 5 is detected by a liquid surface sensor 10 and a valve controller 20 controls the air actuator 12 and the pressure of the nitrogen gas 3 and also controls the slurry supply pipe to prevent the fluctuation of the thickness of the green sheet.

Description

[Detailed Description of the Invention] [Summary] Regarding a slurry supply method, particularly regarding a method of supplying slurry to a slurry dam used when forming a green sheet on a film by the doctor blade method, undesirable plate thickness of the green sheet In a slurry supply method for the purpose of reducing fluctuations, a pressure gas is supplied into a slurry container containing slurry to convey the slurry to a slurry dam disposed near a doctor blade. The slurry liquid level is detected and the signal is used to control the supply of the pressure gas into the slurry container, and the slurry is supplied at at least one point of the slurry supply pipe arranged between the slurry container and the slurry dam. The configuration includes increasing or decreasing the size of the tube.

[Industrial application field]

The present invention relates to a slurry supply method, and particularly to a method for supplying slurry IJ- to a slurry dam used when forming a green sheet on a film by a doctor blade method.

[Conventional technology]

Before manufacturing a multilayer ceramic substrate from glass ceramic or the like, for example, alumina and glass are sized in a ball mill, kneaded, and then formed into a green sheet through a defoaming process.

The above-mentioned green sheet forming process is performed by the method shown in FIG.

That is, the slurry 2 contained in the slurry tank 1 is pressurized with nitrogen gas 3 and sent to the slurry dam 5 through the slurry supply pipe 4, and a certain amount of slurry is accumulated and then passed through the doctor blade 6 and back roll 7. A green sheet is formed by depositing it on a film (not shown).

The thickness of the green sheet formed using the doctor blade must be controlled to be constant.

Conventionally, in order to control the thickness, slurry dam 5
The liquid level of the slurry 2 accumulated in the slurry dam was detected by a liquid level sensor 10, and the signal was fed back to the supply pressure of nitrogen gas to the slurry tank 1 to control the supply of slurry to the slurry dam.

[Problem to be solved by the invention: If the conventional slurry level control method described above is simply on-off control, in the case of a sudden supply stop signal, the pressure memory (pressure remaining in the slurry tank) There was auburn neat (excess supply) in the slurry supply, which had a negative effect on the thickness of the green sheet.

The present invention aims to reduce undesirable thickness variations of green sheets.

[Means to solve the problem]

According to the present invention, in a slurry supply method in which pressure gas is supplied into a slurry container containing slurry and the slurry is conveyed to a slurry dam disposed near a doctor blade, the slurry inside the slurry dam is The slurry liquid level is detected and the signal is used to control the supply of the pressure gas into the slurry container, and the slurry is supplied at at least one point of the slurry supply pipe arranged between the slurry container and the slurry dam. The problem is solved by a slurry supply method characterized by increasing or decreasing the size of the tube.

[For production]

According to the present invention, fluctuations in the slurry liquid level in the slurry dam can be detected and the slurry pumping pressure and the size (thickness) of the slurry supply pipe placed between the slurry container (slurry tank) and the slurry dam can be increased or decreased at the same time. The thickness of the green sheet obtained from the slurry dam via the doctor blade can be kept constant.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic sectional view showing an embodiment for explaining the present invention in detail, and the same elements as those shown in FIG. 2 of the conventional method are designated by the same reference numerals.

The difference in FIG. 1 from the conventional method shown in FIG. 2 is that a silicon tube 11 is used instead of the slurry supply pipe 4, and the tube 11 has an air actuator 12 in the middle.
A partition member 13 made of aluminum or stainless steel is provided inside the slurry dam 5.

``This partition member 13 makes the slurry dam have a two-tiered structure.

In this example, the width of the green sheet (width of the slurry dam)
is 450m+! 1, the length of the first stage of the slurry dam was 5 Q mm, the length of the second stage was 150 mm, and the height of the slurry liquid level was 50 mm at the first stage and 20 mm at the second stage.

Pressurized air (nitrogen gas) 3 is maintained at a pressure of 1 kg/crl during work, and the slurry (consisting of ceramic, resin, solvent, etc.)
to be pumped. The length of the silicone tube 11 is approximately 3mm and the inner diameter is 8I! It was set to 1m. Same liquid level sensor 1 as before
0 to detect the slurry liquid level in the first stage and control the pressure of the air actuator 12 and nitrogen gas 3 via the valve controller 20 to control the slurry supply amount and prevent plate thickness fluctuation in green sheet forming. did.

Note that although the partition member 13 is preferably used in this embodiment, it is also possible to omit it.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to control the slurry liquid level in the slurry dam with higher precision, so that fluctuations in the thickness of the green sheet can be reduced when forming the green sheet.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing an embodiment for explaining the present invention in detail, and FIG. 2 is a schematic sectional view showing a conventional method. ■...Slurry tank, 2...Slurry 3...Pressure air (nitrogen gas), 4...Slurry supply pipe, 5...Slurry dam, 6...Doctor blade, 7...To back rono 10...Liquid level sensor 1
1... Silicon tube, 12... Air actuator 13... Partition member, 20... Valve controller

Claims (1)

[Scope of Claims] 1. A slurry supply method in which pressure gas is supplied into a slurry container containing slurry to convey the slurry to a slurry dam disposed near a doctor blade, comprising: The liquid level is detected and the signal is used to control the supply of the pressure gas into the slurry container, and at least one part of the slurry supply pipe arranged between the slurry container and the slurry dam is connected to the slurry supply pipe. A slurry supply method characterized by increasing or decreasing the size of a slurry.