JP2013039677A - Device and method of manufacturing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for manufacturing a sheet and a method of manufacturing the sheet suppressing a reduction in manufacturing efficiency and allowing manufacture of the sheet having a desired thickness without changing a management indicator.SOLUTION: The device includes a die 20 discharging molten resin in the sheet-shaped form and having a plurality of thickness adjusting means 22 adjusting a molten resin discharging gap 21, a thickness measuring instrument 50 measuring the thickness of the sheet made of the resin discharged from the die 20 while scanning it along its width direction, and a control means 60 preparing a thickness profile from a result of measurement by the thickness measuring instrument 50 and controlling a manipulated variable of the plurality of thickness adjusting means 22 such that the width-wise thickness of the sheet reaches a target value based on the prepared thickness profile. The thickness measuring instrument 50 measures the width-wise thickness of the sheet at a plurality of different scanning speeds. The control means 60 prepares the thickness profile using a result of measurement measured at the plurality of different scanning speeds.

Description

  The present invention relates to a sheet manufacturing apparatus such as a film and a sheet manufacturing method.

  2. Description of the Related Art Conventionally, an apparatus for manufacturing a sheet such as a film is generally configured to include a die, a stretching machine, a winder, a thickness measuring device, and a control unit. The die discharges the molten resin extruded from the extruder into a sheet shape. Such a die is provided with a plurality of thickness adjusting means for adjusting the discharge gap. The stretching machine stretches the sheet-like resin discharged from the die in the transport direction (hereinafter also referred to as MD (Machine Direction) direction) and the width direction (hereinafter also referred to as TD (Transversal Direction) direction). A sheet is formed. The winder winds a sheet formed by a stretching machine in a roll shape.

  The thickness measuring device is generally disposed between the die and the stretching machine and / or between the stretching machine and the winder, and the sensor is predetermined along the width direction of the sheet. By reciprocating at a constant speed, the thickness of the sheet is measured as a distribution in the TD direction. The control means creates a thickness profile from the measurement result of the thickness measuring instrument, and uses the created thickness profile and a preset desired thickness profile so that the thickness in the width direction of the sheet becomes a target value. For example, the operation amount of the thickness adjusting means is controlled by PID control.

  In such a sheet control device, it is possible to manufacture a sheet having a desired thickness by feeding back the measurement result of the thickness measuring device and controlling the operation amount of the thickness adjusting means.

  However, due to uneven discharge of the molten resin discharged from the die, uneven stretching in the MD direction by the stretching machine, film vibration between the die and the cooling drum provided in the vicinity of the discharge gap of this die, etc. Has a thickness distribution also in the MD direction of the sheet. For this reason, the thickness distribution in the MD direction is included in the measurement result of the thickness measuring instrument in addition to the thickness distribution in the TD direction. Therefore, if the measurement result is fed back as it is to control the operation amount of the thickness adjusting means, the thickness unevenness is created, and there is a possibility that a sheet having a desired thickness cannot be manufactured.

  Therefore, the scanning speed for reciprocating the sensor is set to a predetermined speed determined in advance from the conditions in the manufacturing process so that the thickness meter can measure only the thickness distribution in the TD direction by removing the thickness distribution component in the MD direction. Has been proposed (see, for example, Patent Document 1).

JP 2003-291204 A

  However, in the manufacturing apparatus proposed in Patent Document 1 described above, since the scan speed of the sensor is slower than a predetermined speed obtained in advance from the conditions in the manufacturing process, the scan speed of the sensor is low. It will be slower than before. Generally, since the control of the adjustment amount of the thickness adjusting means is performed at the timing when the sensor reaches the scanning end, the time interval for controlling the operation amount of the thickness adjusting means becomes long, resulting in the sheet being This causes a decrease in manufacturing efficiency.

  Moreover, in the manufacturing apparatus proposed in Patent Document 1, since the thickness distribution component in the MD direction is removed by making the scan speed of the sensor slower than in the past, the MD direction to the thickness profile created by the thickness measuring instrument The influence of the thickness distribution component is different. Since this thickness profile is generally also used for thickness management, various management indexes associated with sheet manufacture must be changed.

  In view of the above circumstances, the present invention is a sheet manufacturing apparatus and sheet manufacturing method capable of manufacturing a sheet having a desired thickness without suppressing a decrease in manufacturing efficiency and without requiring a change in management index. The purpose is to provide.

  In order to achieve the above object, a sheet manufacturing apparatus according to claim 1 of the present invention discharges molten resin in a sheet shape, and has a plurality of thickness adjusting means for adjusting the discharge gap of the molten resin. A thickness profile is created from a measurement result of the die, a thickness measurement unit that scans the thickness of the sheet formed from the sheet-like resin discharged from the die along the width direction, and a measurement result by the thickness measurement unit. An apparatus for manufacturing a sheet having a desired thickness, comprising: a control unit that controls an operation amount of the plurality of thickness adjusting units so that a thickness in the width direction of the sheet becomes a target value based on the created thickness profile The thickness measuring means measures the thickness in the width direction of the sheet at a plurality of different scanning speeds, and the control means has a plurality of different thicknesses. Characterized in that to create the thickness profile by using the measurement results measured by the scanning speed.

  The sheet manufacturing apparatus according to a second aspect of the present invention is the sheet manufacturing apparatus according to the first aspect, wherein the control means integrates the measurement results measured at a plurality of different scanning speeds to create the thickness profile. It is characterized by that.

  The sheet manufacturing apparatus according to a third aspect of the present invention is the sheet manufacturing apparatus according to the first or second aspect, wherein the thickness measuring means is configured so that the forward scanning speed and the backward scanning speed are different. The thickness of the sheet is measured by reciprocating along the width direction.

  The sheet manufacturing apparatus according to claim 4 of the present invention is the sheet manufacturing apparatus according to any one of claims 1 to 3, wherein the thickness measuring unit reciprocates along the width direction of the sheet. The sheet thickness is measured, and the scanning speed varies depending on the position in the sheet width direction in the forward path and / or the backward path.

  In the sheet manufacturing method according to claim 5 of the present invention, the thickness measurement is performed by scanning the thickness of the sheet formed from the resin discharged from the die having a plurality of thickness adjusting means along the width direction of the sheet. A thickness measurement step measured by means, a thickness profile creation step for creating a thickness profile from the measurement result of the thickness measurement step, and the thickness of the sheet based on the thickness profile created in the thickness profile creation step And calculating a manipulated variable of the plurality of thickness adjusting means so that a sheet having a desired thickness is manufactured, wherein the thickness measuring step is performed at a plurality of different scanning speeds through the thickness measuring means. Measuring the thickness in the width direction of the sheet, and the thickness profile creating step comprises measuring the thickness profile. Through le forming means, characterized in that to create the thickness profile by using the measurement results measured by different scanning speeds.

  The sheet manufacturing method according to claim 6 of the present invention is the sheet manufacturing method according to claim 5, wherein the thickness profile creating step integrates measurement results measured at a plurality of different scanning speeds through the thickness profile creating means. Processing to create the thickness profile.

  The sheet manufacturing method according to a seventh aspect of the present invention is the sheet manufacturing method according to the fifth or sixth aspect, wherein the thickness measurement step is performed in such a manner that the scanning speed of the outward path and the scanning speed of the backward path are different. The means measures the thickness of the sheet by reciprocating along the width direction of the sheet.

  The sheet manufacturing method according to an eighth aspect of the present invention is the sheet manufacturing method according to any one of the fifth to seventh aspects, wherein the thickness measuring unit reciprocates along the width direction of the sheet. The thickness of the sheet is measured by moving, and the scanning speed varies depending on the position in the sheet width direction in the forward path and / or the backward path.

  According to the sheet manufacturing apparatus of the present invention, since the thickness measuring unit measures the thickness in the width direction of the sheet at a plurality of different scanning speeds, the phase of the thickness unevenness component in the sheet conveyance direction is set. Can be obtained as data. In addition, since the control means creates a thickness profile using the measurement results measured at a plurality of different scanning speeds, the thickness unevenness component in the transport direction of the sheet that is out of phase is added, resulting in a phase shift state. By setting this, it is possible to reduce the influence of thickness unevenness in the sheet conveyance direction. As a result, it is possible to obtain the thickness unevenness data in the width direction by reducing the influence of the thickness unevenness in the conveyance direction of the sheet. Using the thickness unevenness data in the width direction, the thickness in the width direction of the sheet is the target value. Since the operation amount of the plurality of thickness adjusting means is controlled so as to satisfy the following, a sheet having a desired thickness can be manufactured. In addition, since the measurement by the thickness measurement means is only performed at different scanning speeds, the measurement time by the thickness measurement means can secure a desired range, and the manufacturing efficiency due to the slow scan speed as in the prior art. There is no risk of a decline. If one of the scanning speeds to be set is set to the same speed as the conventional one, the same thickness management as the conventional one can be realized by using the thickness profile at that time. Therefore, it is possible to manufacture a sheet having a desired thickness without suppressing a decrease in manufacturing efficiency and without requiring a change in management index.

  Further, according to the sheet manufacturing method of the present invention, since the thickness measurement step measures the thickness in the width direction of the sheet at a plurality of different scanning speeds through the thickness measuring means, the thickness unevenness component in the sheet conveyance direction Can be acquired as data while causing a set deviation. In addition, since the thickness profile creation process creates a thickness profile using the measurement results measured at a plurality of different scanning speeds through the thickness profile creation means, the thickness unevenness component in the transport direction of the sheet that is out of phase is added. Therefore, by setting the phase shift, the influence of thickness unevenness in the sheet conveyance direction can be reduced. As a result, it is possible to obtain the thickness unevenness data in the width direction by reducing the influence of the thickness unevenness in the conveyance direction of the sheet. Using the thickness unevenness data in the width direction, the thickness in the width direction of the sheet is the target value. Since the operation amount of the plurality of thickness adjusting means is controlled so as to satisfy the following, a sheet having a desired thickness can be manufactured. In addition, since the measurement by the thickness measuring means is only performed at different scanning speeds, the measurement time in the thickness measuring process can secure a desired range, and the manufacturing efficiency can be improved by slowing down the scanning speed as in the past. There is no risk of a decline. If one of the scanning speeds to be set is set to the same speed as the conventional one, the same thickness management as the conventional one can be realized by using the thickness profile at that time. Therefore, it is possible to manufacture a sheet having a desired thickness without suppressing a decrease in manufacturing efficiency and without requiring a change in management index.

FIG. 1 is a schematic configuration diagram of a sheet manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a die constituting the sheet manufacturing apparatus shown in FIG. FIG. 3 is a schematic diagram schematically showing a characteristic control system of the sheet manufacturing apparatus shown in FIG. FIG. 4 is a flowchart showing the contents of the thickness adjustment process performed by the control means shown in FIGS.

  Exemplary embodiments of a sheet manufacturing apparatus and a sheet manufacturing method according to the present invention will be explained below in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of a sheet manufacturing apparatus according to an embodiment of the present invention. The sheet manufacturing apparatus 1 exemplified here includes an extruder 10, a die 20, a stretching machine 30, a winder 40, a thickness measuring device (thickness measuring means) 50, and a control means 60. The extruder 10 extrudes a resin (for example, PET (polyethylene terephthalate)), which is a raw material of the sheet, in a heated and melted state.

  FIG. 2 is a perspective view showing a die 20 constituting the sheet manufacturing apparatus 1 shown in FIG. As shown in FIG. 2, the die 20 has a slit-shaped discharge gap 21, and the molten resin extruded from the extruder 10 is discharged from the discharge gap 21 into a sheet shape. The resin discharged in a sheet form from the discharge gap 21 is cooled by the cooling drum 2 and solidifies.

  The die 20 is provided with a plurality of thickness adjusting means 22. These thickness adjusting means 22 are provided at equal intervals in a manner of being arranged along the longitudinal direction of the discharge gap 21, and adjust the size of the discharge gap 21. Here, as the thickness adjusting means 22 according to the present embodiment, a heat bolt method is adopted in which a bolt incorporating a cartridge heater is thermally expanded and contracted to adjust the size of the discharge gap 21.

  The stretching machine 30 forms a sheet by stretching the sheet-like resin cooled by the cooling drum 2 and transported via the transport roller 3 in the transport direction (MD direction) and the width direction (TD direction). Is.

  The winder 40 winds a sheet formed by the stretching machine 30 and conveyed via the conveying roller 3 in a roll shape.

  The thickness measuring device 50 is disposed between the stretching machine 30 and the winder 40, and the thickness of the sheet is determined by reciprocating the sensor 51 (see FIG. 3) along the TD direction of the sheet. The measurement is performed for each predetermined portion (that is, the adjustable region corresponding to the operation point of each thickness adjusting means 22) and measured as a distribution in the TD direction.

  As such a thickness measuring device 50, an arbitrary device such as a device using an absorptivity of β rays, infrared rays, ultraviolet rays, X rays, etc., a device using light interference phenomenon, etc. can be adopted. As the thickness measuring instrument 50 in the form, a device using a β-ray absorption phenomenon is adopted.

  Further, in the thickness measuring instrument 50, the forward scanning speed and the backward scanning speed of the sensor 51 are made different. More specifically, when the length in the width direction of the sheet is 3500 mm and the sheet conveyance speed at the position where the thickness measuring device 50 measures the thickness is 100 m / min, the scanning time of the forward path of the sensor 51 is set to, for example, Forty seconds (same scan speed as before) and the return scan time is set to 35 seconds, for example, and the forward scan speed and the return scan speed are different.

  The scanning speed of the reciprocating movement of the sensor 51 in the thickness measuring device 50 is set as follows. Needless to say, the following is an example, and the present invention is not limited to this.

  The sensor 51 of the thickness measuring device 50 is fixedly arranged at the center in the TD direction of the sheet, the thickness along the MD direction of the sheet is measured, and the measurement result is Fourier-transformed to examine the spectrum. It is assumed that it has been found that there is a thickness unevenness having a peak near 0.5 Hz in the direction. Next, consider the scanning speed at which the sensor 51 is reciprocated along the TD direction of the sheet. At this time, the forward scan time of the sensor 51 is fixed to, for example, the same 40 seconds as in the prior art, and the backward scan time is determined by simulation. In this simulation, the actually measured thickness unevenness in the MD direction is used to determine the scan time for the return path that minimizes the influence of the thickness unevenness in the MD direction. Specifically, the scanning speed of the sensor 51 on the return path is changed, and thickness unevenness in the MD direction measured at each position in the width direction of the sheet is calculated at each scanning speed. Then, the thickness unevenness measurement values that are continuously repeated at each TD position are added over the entire width of the sheet. The scan time of the return path in which the difference between the maximum value and the minimum value of the added value of the thickness unevenness measurement values over the entire width of the sheet is the smallest is obtained, and the scan speed calculated based on the scan time Set to speed. Here, thickness unevenness measurement values for 10 times were added.

  FIG. 3 is a schematic diagram schematically showing a characteristic control system of the sheet manufacturing apparatus 1 shown in FIG. As shown in FIG. 3, the control means 60 includes a control processing unit 61. The control processing unit 61 controls the operation amounts of the plurality of thickness adjusting means 22 according to data and programs stored in the memory 62. The control processing unit 61 includes an input processing unit 611, a thickness profile creation processing unit 612, and an operation amount calculation processing unit 613. And an output processing unit 614 as a main component.

  When the sensor 51 constituting the thickness measuring instrument 50 measures the thickness of the sheet, the input processing unit 611 inputs a measurement signal that is a measurement result from the sensor 51. The measurement result input by the input processing unit 611 is stored in the memory 62 as appropriate.

  The thickness profile creation processing unit 612 performs integration processing on the measurement result input through the input processing unit 611 and the measurement result for the most recent predetermined number of times (for example, nine times) stored in the memory 62, that is, For example, the measurement results for 10 times are integrated and a thickness profile for each location corresponding to the operating point of each thickness adjusting means 22 in the TD direction of the sheet is created. Thus, the thickness profile creation processing unit 612 creates a thickness profile by integrating the measurement results measured at a plurality of different scanning speeds.

  The operation amount calculation processing unit 613 obtains a deviation between the thickness profile created through the thickness profile creation processing unit 612 and the target thickness profile stored in advance in the memory 62, and performs PID calculation based on the deviation to perform each PID calculation. The operation amount of the thickness adjusting means 22 is calculated.

  The output processing unit 614 outputs the operation amount calculated through the operation amount calculation processing unit 613 to each thickness adjusting unit 22 via a power unit (not shown).

  FIG. 4 is a flowchart showing the processing contents of the thickness adjustment processing performed by the control means 60 shown in FIGS. This thickness adjustment processing is performed every time the thickness measuring instrument 50 measures the thickness of the sheet once, that is, every time when the movement of one way (outward path or backward path) when reciprocating along the width direction of the sheet is completed. Is.

  In this thickness adjustment processing, the control means 60 creates a thickness profile through the thickness profile creation processing unit 612 when the measurement result is input from the sensor 51 constituting the thickness measuring device 50 through the input processing unit 611 (step S101: Yes). (Step S102).

  In step S102, the control means 60 performs an integration process on the measurement result input through the input processing unit 611 and the measurement result for the most recent predetermined number of times (for example, nine times) stored in the memory 62, A thickness profile is created for each location corresponding to the operating point of each thickness adjusting means 22 in the TD direction of the sheet.

  The control means 60 that created the thickness profile obtains a deviation between the thickness profile and the target thickness profile read from the memory 62 through the operation amount calculation processing unit 613, performs PID calculation based on the deviation, and adjusts each thickness. The operation amount of the means 22 is calculated (step S103).

  Then, the control unit 60 outputs the calculated operation amount to each thickness adjusting unit 22 through the output processing unit 614 (step S104), and then returns the procedure to end the current process. However, only this step S104 may be performed every time the thickness measuring instrument 50 measures the sheet thickness a preset number of times.

  As described above, the control unit 60 creates a thickness profile from the measurement result of the thickness measuring device 50, and operates the plurality of thickness adjusting units 22 based on the created thickness profile so that the thickness in the TD direction of the sheet becomes a target value. The amount is to be controlled.

  In the sheet manufacturing apparatus 1 according to the present embodiment, the thickness measuring device 50 reciprocates along the TD direction of the sheet in a manner in which the scanning speed of the forward path and the scanning speed of the backward path are different, thereby reducing the thickness of the sheet. Since the measurement is performed, it is possible to acquire a thickness unevenness (for example, 0.5 Hz) component in the MD direction of the sheet as data in a state where the set phase shift is provided. And since the control means 60 integrates the measurement results measured at a plurality of different scanning speeds to create a thickness profile, the data in a phase shifted state are stacked, resulting in the MD direction of the sheet. The effect of uneven thickness can be reduced. Thereby, it is possible to obtain the data of the thickness unevenness in the TD direction by minimizing the influence of the thickness unevenness in the MD direction of the sheet, and the thickness in the TD direction of the sheet is the target value by using the data of the thickness unevenness in the TD direction. Since the operation amount of the plurality of thickness adjusting means 22 is controlled so as to satisfy the following, a sheet having a desired thickness can be manufactured.

  In addition, since the scanning speed by the thickness measuring device 50 is merely different between the forward path and the backward path, the scanning time required for the reciprocating movement can ensure a desired range, and the scanning speed can be increased as in the past. There is no possibility of causing a decrease in production efficiency due to slowing down.

  Therefore, according to the sheet manufacturing apparatus 1 according to the embodiment of the present invention, a sheet having a desired thickness can be manufactured while suppressing a decrease in manufacturing efficiency.

  According to the sheet manufacturing apparatus 1, since the scanning speed by the thickness measuring device 50 is merely different between the forward path and the backward path, for example, the thickness profile measured at the scanning speed with the forward path set to the same scan speed as before. If the thickness management by is performed, it is possible to use the same management index as the conventional one.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to this, and various modifications can be made.

  In the embodiment described above, the thickness profile creation processing unit 612 of the control means 60 creates the thickness profile by integrating the measurement results measured at a plurality of different scan speeds. In addition to the integration processing, the integration processing may be performed by weighting or the like, or the thickness profile may be created using a method other than the integration processing.

  In the above-described embodiment, the scanning speed by the thickness measuring device 50 is changed between the forward path and the backward path. However, in the present invention, the thickness measuring unit has a plurality of sensors, and the plurality of sensors are different from each other. The thickness in the width direction of the sheet may be measured at the scanning speed. Also by this, data in a state where the set phase shift is given is acquired, and by stacking these data, it is possible to reduce the influence of thickness unevenness in the sheet conveyance direction.

  In the above-described embodiment, the scanning speed by the thickness measuring device 50 is changed between the forward path and the backward path. However, in the present invention, the scanning speed may be periodically changed. Also by this, data in a state where the set phase shift is given is acquired, and by stacking these data, it is possible to reduce the influence of thickness unevenness in the sheet conveyance direction.

  As described above, the sheet manufacturing apparatus and the sheet manufacturing method according to the present invention are useful for manufacturing a sheet such as a film having a predetermined thickness.

DESCRIPTION OF SYMBOLS 1 Sheet manufacturing apparatus 10 Extruder 20 Die 21 Discharge gap 22 Thickness adjustment means 30 Stretching machine 40 Winding machine 50 Thickness measuring device 51 Sensor 60 Control means 61 Control processing part 611 Input processing part 612 Thickness profile creation processing part 613 Operation amount Calculation processing unit 614 Output processing unit 62 Memory

Claims (8)

A die having a plurality of thickness adjusting means for adjusting the discharge gap of the molten resin, which discharges the molten resin into a sheet shape,
A thickness measuring means for measuring the thickness of the sheet formed from the sheet-like resin discharged from the die while scanning along the width direction;
A control unit that creates a thickness profile from the measurement result of the thickness measurement unit, and controls the operation amounts of the plurality of thickness adjustment units based on the created thickness profile so that the thickness in the width direction of the sheet becomes a target value; In an apparatus for manufacturing a sheet having a desired thickness,
The thickness measuring means measures the thickness in the width direction of the sheet at a plurality of different scanning speeds,
The sheet producing apparatus, wherein the control unit creates the thickness profile using measurement results measured at a plurality of different scanning speeds.   2. The sheet manufacturing apparatus according to claim 1, wherein the control unit creates the thickness profile by integrating the measurement results measured at a plurality of different scanning speeds.   The thickness measurement unit measures the thickness of the sheet by reciprocating along the width direction of the sheet in a manner in which the scanning speed of the forward path and the scanning speed of the backward path are different. Item 3. The sheet manufacturing apparatus according to Item 2.   The thickness measuring means measures the thickness of the sheet by reciprocating along the width direction of the sheet, and the scanning speed changes depending on the position in the sheet width direction in the forward path and / or the return path. The sheet manufacturing apparatus according to claim 1, wherein A thickness measuring step of measuring the thickness of the sheet formed from the resin discharged from the die having a plurality of thickness adjusting means by a thickness measuring means that scans along the width direction of the sheet;
A thickness profile creating step for creating a thickness profile from the measurement result of the thickness measuring step;
A calculation step of calculating an operation amount of the plurality of thickness adjusting means so that the thickness of the sheet becomes a target value based on the thickness profile created in the thickness profile creation step, and manufacturing a sheet having a desired thickness In the way to
The thickness measuring step is to measure the thickness in the width direction of the sheet at a plurality of different scanning speeds through the thickness measuring means,
The thickness profile creating step creates the thickness profile using the measurement results measured at a plurality of different scanning speeds through the thickness profile creating means.   The sheet manufacturing method according to claim 5, wherein the thickness profile creating step creates the thickness profile by integrating the measurement results measured at a plurality of different scanning speeds through the thickness profile creating means. Method.   The thickness measuring step is characterized in that the thickness measuring unit measures the thickness of the sheet by reciprocating along the width direction of the sheet in a manner in which the scanning speed of the forward path and the scanning speed of the backward path are different. The manufacturing method of the sheet | seat of Claim 5 or Claim 6.   In the thickness measuring step, the thickness measuring unit measures the thickness of the sheet by reciprocating along the width direction of the sheet, and is scanned according to the position in the sheet width direction in the forward path and / or in the return path. The method of manufacturing a sheet according to any one of claims 5 to 7, wherein the speed is changed.

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