JP2004125756A - Method and apparatus for measuring dimension of gap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a dimensional variation of a gap in a width direction of coating made by a discharge slit of a die-head without damaging the discharge slit. <P>SOLUTION: In the measuring method, a measuring block 6 is installed so as to cover a portion of a discharge opening 2a of the discharge slit 2, and air is introduced from the discharge slit into the measuring block 6 by acting the vacuum of a vacuum tank 8 keeping a constant vacuum level, and a pressure resistance value of the air generated during above air introduction is measured by a differential pressure gauge 11. The measurement of the pressure resistance value is carried out at a plurality of measurement points arranged in the width direction of the coating made by the discharge slit, and the dimensional variation of the gap in the discharge slit is determined from the variation of the measured values. Alternatively, a pressurized tank keeping a constant pressure level is used instead of the vacuum tank 8, and pressurized air is injected into the discharge slit through the measuring block 6, and the pressure resistance value is measured, thereby measuring the dimensional variation of the gap. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for measuring a variation in a gap width of a discharge slit of a die head in a coating width direction (longitudinal direction of a die head) for coating a coating liquid on a web, a plate material, or the like in a strip shape.
[0002]
[Prior art]
Conventionally, as means for coating a web or a plate material, as shown in FIG. 6, a discharge slit 2 having a narrow width gap and a supply passage (not shown) for supplying a coating liquid thereto are provided. Die head 1 is used. In the coating using the die head 1, the gap dimension d of the discharge slit 2 is an important factor of the coating thickness, and in order to reduce the thickness unevenness in the coating width direction, the gap dimension d is applied. It is necessary to make it uniform in the width direction (the longitudinal direction of the die head 1). Therefore, it is necessary to measure variations in the gap width d in the application width direction. Conventionally, a gap gauge 4 made of stainless steel has been adopted as a method of measuring the variation in the gap dimension in the application width direction. That is, the gap gauge 4 is inserted into the discharge slit 2, and the thickness of the gap gauge when the gap gauge 4 reaches the limit at which the gap gauge 4 can be pulled out is defined as a gap dimension, and measurement is performed at a plurality of points in the coating width direction. I knew the variation in
[0003]
[Problems to be solved by the invention]
However, the resolution of the gap gauge is limited to about 10 μm, and there is a problem that the resolution (about 1 μm) required for high-precision coating recently required is not satisfied. In addition, in the case of the gap gauge made of stainless steel, since the gap gauge is brought into direct contact with the inner surface of the discharge slit, there is also a problem that the inner surface of the discharge slit is damaged.
[0004]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a technique capable of measuring a variation in a gap dimension in a coating width direction with high accuracy without damaging a discharge slit. .
[0005]
[Means for Solving the Problems]
The present invention utilizes the pressure resistance of air generated at the time of suction or injection of air from a discharge slit in order to measure variations in the gap dimension in the application width direction. That is, in the present invention, the operation of sucking or injecting air from a partial area of the discharge port of the discharge slit and measuring the pressure resistance value of the air generated at that time is performed in different areas in the application width direction of the discharge slit. And the variation of the gap size of the discharge slit is measured from the variation of the measured value. Since the measured pressure resistance value of the air is a value corresponding to the gap size of the discharge slit, by measuring the variation of the pressure resistance value, the variation of the gap size can be detected, and therefore, the inner surface of the discharge slit can be detected. The gap size variation can be measured without damage.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
One embodiment of a gap size measuring apparatus used for carrying out the present invention is a measuring block that covers a partial area of a discharge port of a discharge slit formed in a die head and has a passage for sucking air from the discharge port. A decompression tank connected to the measurement block via an air hose, a means for maintaining the inside of the decompression tank at a predetermined pressure, and a pressure measurement means for measuring a pressure in the air hose in or near the measurement block. Is provided. With this configuration, the measurement block is set on the discharge port of the discharge slit, suction is performed by applying vacuum from the decompression tank, and the pressure in the measurement block at that time or in the air hose near the pressure measurement is measured. By measuring by means, the pressure resistance value of the air in the discharge slit in the area where the measuring block is set can be measured, and the same operation is performed at a plurality of points in the application width direction of the discharge slit, so that the gap dimension can be reduced. Variation in the coating width direction can be measured without damaging the inner surface of the discharge slit.
[0007]
Another embodiment of the gap size measuring device includes a measurement block that covers a partial area of the discharge port of a discharge slit formed in a die head and includes a passage for supplying air to the discharge port. A pressurized tank connected to the block via an air hose, a means for maintaining the inside of the pressurized tank at a predetermined pressure, and a pressure measuring means for measuring the pressure in the air hose in or near the measuring block. It is configured. Also in this configuration, the measurement block is set on the discharge port of the discharge slit, air is supplied from the pressurized tank, and the pressure in the measurement block at that time or in the air hose in the vicinity thereof is measured by a pressure measurement unit. By measuring, the pressure resistance value of the air in the discharge slit in the area where the measurement block is set can be measured, and the same operation is performed at a plurality of points in the application width direction of the discharge slit, so that the application width of the gap dimension is obtained. The variation in the direction can be measured without damaging the inner surface of the discharge slit.
[0008]
The measurement block used in the above-described apparatus is preferably formed of a resin block having a contact surface that can be in close contact with the top surface of the die head so as to straddle the discharge port. With this configuration, when measuring pressure is performed by pressing the measurement block against a desired position on the tip surface of the die head, air leakage between the measurement block and the die head is satisfactorily prevented to improve measurement accuracy. In addition, since the measuring block is made of resin, the tip surface of the die head such as the lip surface is not damaged.
[0009]
The measurement block is provided with a film material for preventing air leakage by contacting the surface of the die head at the lower end portions on both sides thereof, so that air leakage can be further prevented and accurate measurement can be performed. preferable.
[0010]
Hereinafter, preferred embodiments of the present invention shown in the drawings will be described. FIG. 1 is a schematic perspective view showing a gap size measuring apparatus according to an embodiment of the present invention in a state where a gap size of a discharge slit 2 of a die head 1 is being measured. The gap size measuring apparatus generally designated by reference numeral 5 includes a measuring block 6, a pressure reducing tank 8 connected to the measuring block 6 via an air hose 7, and an air supply hose 9 connected to the pressure reducing tank 8. A means (not shown) connected to and connected to the vacuum tank 8 for vacuum suction to maintain a predetermined pressure (a predetermined degree of vacuum), a differential pressure gauge 10 for detecting the pressure in the vacuum tank 8, and a measuring block 6 Alternatively, a pressure measuring means for measuring the pressure in the air hose 7 in the vicinity thereof, for example, a differential pressure gauge 11 is provided. Here, the measuring block 6 covers a partial area in the longitudinal direction of the discharge port 2a of the discharge slit 2 formed in the die head 1, as shown in cross sections in FIGS. 2 (a) and 2 (b). It has a structure that can be mounted as described above and has a passage 12 that sucks air from the discharge port 2a, and the passage 12 is connected to the air hose 7 (see FIG. 1). Further, this measuring block 6 can be tightly attached to the top surface of the die head 1 so as to straddle the discharge port so as to prevent air from leaking from the periphery when the discharge port 2a is suctioned from the passage 12 and to be sucked. The contact surface 6a is provided. The measurement block 6 is formed of a resin block so as not to damage the lip surface of the die head 1 when pressed against the front end surface of the die head 1. Further, a film material 14 such as a fluororesin film which is in contact with the surface of the die head 1 to prevent air leakage is attached to the lower end portions on both sides of the measurement block 6. The dimension L of the measurement block 6 in the longitudinal direction of the discharge slit may be selected to be about 10 to 50 mm, preferably about 25 to 30 mm.
[0011]
Next, the gap size measuring operation will be described. The measurement block 6 is mounted on the die head 1 so as to cover the area where the gap dimension of the discharge slit 2 is to be measured, and the vacuum tank 8 is evacuated to a predetermined degree of vacuum. Thus, the vacuum in the pressure reducing tank 8 acts on the measuring block 6, and air is sucked from the discharge slit 2 through the passage 12. At this time, the pressure value (the differential pressure value in this case) indicated by the differential pressure gauge 11 depends on the magnitude of the amount of air sucked from the discharge slit 2, and the amount of air depends on the magnitude of the pressure resistance value of the discharge slit 2. It is according to. The pressure resistance value is in accordance with the gap size of the discharge slit 2. Therefore, the pressure value indicated by the differential pressure gauge 11 corresponds to the pressure resistance value corresponding to the gap size of the discharge slit 2 at the measurement position. In addition, the pressure value indicated by the differential pressure gauge 11 changes within a sufficiently detectable range even in response to a slight change in the gap size, for example, a change of about 1 μm in the discharge slit 2 having a gap size of 30 μm. Therefore, the pressure value is measured by the differential pressure gauge 11 while the air is sucked from the measurement block 6, and then the measurement block 6 is moved to another measurement point of the discharge slit 2. Measure the pressure value. Hereinafter, the same operation is successively performed on a plurality of points to be measured in the application width direction of the discharge slit 2 to measure the variation in the pressure value. Since the obtained variation in the pressure value corresponds to the variation in the gap size, the variation in the gap size is ultimately measured. That is, by performing the measurement of the pressure value at a plurality of points in the application width direction of the discharge slit 2, a slight variation in the gap dimension in the application width direction, for example, a variation of 1 μm or less can be measured. In addition, since the inner surface of the discharge slit is not in contact with the surface during the measurement, the inner surface of the discharge slit is not damaged.
[0012]
FIG. 4 shows the differential pressure gauge 11 in a state where the vacuum tank 8 is maintained at a degree of vacuum of a differential pressure value of 600 mmAq and the vacuum from the vacuum tank 8 is applied to the measuring block 6 in the gap size measuring apparatus of FIG. 5 is a graph obtained by measuring a relationship between a reading (differential pressure value) and a gap size. As is clear from this graph, when the discharge slit 2 is wide (when the gap size is large), the pressure resistance value is small, so that the air amount increases and the differential pressure value decreases. Pressure value is too large. In addition, the differential pressure value changes considerably with the change in the gap size. Therefore, even a slight change in the gap size can be detected. FIG. 5 is a graph showing differential pressure values measured by the differential pressure gauge 11 at nine measurement points in the application width direction of the discharge slit having a gap size of 30 μm. As is clear from this graph, the measured differential pressure values varied. The gap size of the discharge slit 2 used for the measurement could not be measured with the gap gauge, but only at each measurement point of 30 μm.
[0013]
In the embodiment shown in FIG. 1, air is sucked from the discharge slit 2 by the measuring block 6, and the pressure value at that time is measured to measure the variation in the gap size. Even if the compressed air is injected, the variation in the gap size can be measured in the same manner. FIG. 3 is a schematic perspective view showing the gap dimension measuring apparatus according to the embodiment in that case in a state where the gap dimension of the discharge slit 2 of the die head 1 is being measured. The gap size measuring device 15 of this embodiment includes a measuring block 6, a pressurized tank 18 connected to the measuring block 6 via an air hose 7, and an air supply hose 9 connected to the pressurized tank 18. A means (not shown) for supplying pressurized air into the pressurized tank 18 and maintaining the same at a predetermined pressure; a pressure gauge 20 for detecting the pressure in the pressurized tank 18; Alternatively, a pressure measuring means for measuring the pressure in the air hose 7 in the vicinity thereof, for example, a pressure gauge 21 or the like is provided. The measurement block 6 has the same structure as the measurement block 6 used in the embodiment shown in FIGS.
[0014]
3, the measurement block 6 is mounted on the die head 1 so as to cover the area where the gap size of the discharge slit 2 is to be measured, and the pressurizing tank 18 is pressurized so as to have a predetermined pressure. Supply compressed air. Thereby, the air in the pressurized tank 18 is supplied to the measurement block 6 and is injected into the discharge slit 2 through the internal passage. At this time, the pressure value indicated by the pressure gauge 21 corresponds to the magnitude of the amount of air injected into the discharge slit 2, and therefore corresponds to the pressure resistance value corresponding to the gap dimension of the discharge slit 2. ing. Therefore, the pressure value is measured by the pressure gauge 21 while air is being injected from the measurement block 6, and then the measurement block 6 is moved to another measurement point of the discharge slit 2. Measure the pressure value. Hereinafter, the same operation is successively performed for a plurality of points to be measured, and a slight variation in the gap size can be measured from the variation in the measured pressure value. That is, by performing the measurement of the pressure value at a plurality of points in the application width direction of the discharge slit 2, a slight variation in the gap dimension in the application width direction, for example, a variation of 1 μm or less can be measured. In addition, since the inner surface of the discharge slit is not in contact with the surface during the measurement, the inner surface of the discharge slit is not damaged.
[0015]
【The invention's effect】
As described above, according to the present invention, the operation of sucking or injecting air from a part of the discharge opening of the discharge slit of the die head and measuring the pressure resistance value of the air generated at that time is performed by the discharge slit of the discharge slit. Performed in different areas of the outlet, and by measuring the variation in the gap size of the discharge slit from the measurement value variation, it is possible to detect even a slight variation in the gap size in the application width direction of the discharge slit, therefore This has the effect that the variation in the gap dimension can be measured with high accuracy without damaging the inner surface of the discharge slit.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a gap size measuring apparatus according to an embodiment of the present invention. FIG. 2 (a) A schematic cross section showing a measuring block 6 and a die head 1 in a cross section perpendicular to the longitudinal direction of the die head. FIG. 3B is a schematic sectional view of the measuring block 6 and the die head 1 as viewed in the direction of arrows AA in FIG. 3A. FIG. 3 is a schematic perspective view of a gap size measuring apparatus according to another embodiment of the present invention. 4 is a graph showing a relationship between a reading (differential pressure value) of a differential pressure gauge 11 measured by a gap size measuring device shown in FIG. 1 and a gap size. FIG. 5 is a graph showing a difference measured by a gap size measuring device shown in FIG. FIG. 6 is a graph showing the relationship between the reading of a pressure gauge 11 (differential pressure value) and the position of a discharge slit. FIG. 6 is a schematic perspective view showing a die head and a gap gauge.
DESCRIPTION OF SYMBOLS 1 Die head 2 Discharge slit 2a Discharge port 5, 15 Gap size measuring device 6 Measurement block 7 Air hose 8 Decompression tank 9 Air hose 10, 11 Differential pressure gauge 12 Passage 14 Film material 18 Pressurized tank 20, 21 Pressure gauge

Claims (5)

A method for measuring variation in a gap dimension in a coating width direction of a discharge slit formed in a die head, wherein air is sucked or injected from a partial area of a discharge port of the discharge slit, and air generated at that time is sucked or injected. Performing the operation of measuring the pressure resistance value of the discharge slit in different regions in the application width direction of the discharge slit, and measuring the gap size variation in the application width direction of the discharge slit from the measurement value variation. Dimension measurement method. A measurement block that covers a partial area of the discharge port of the discharge slit formed in the die head and includes a passage for sucking air from the discharge port, and a decompression tank connected to the measurement block via an air hose. A gap size measuring apparatus comprising: means for maintaining the inside of the pressure reducing tank at a predetermined pressure; and pressure measuring means for measuring the pressure in an air hose in or near the measuring block. A measuring block which covers a partial area of the discharge port of the discharge slit formed in the die head and has a passage for supplying air to the discharge port, and a pressurized tank connected to the measurement block via an air hose And a means for maintaining the pressure in the pressurized tank at a predetermined pressure, and a pressure measuring means for measuring a pressure in an air hose in or near the measuring block. The gap size measuring apparatus according to claim 2, wherein the measurement block is formed of a resin block having a contact surface that can be in close contact with the top surface of the die head so as to straddle the discharge port. 5. . 5. The gap size measuring apparatus according to claim 4, wherein said measurement block has a film material attached to a lower end portion on both sides thereof to prevent air leakage by contacting a surface of said die head.

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