JP3576009B2 - Operation control method of sheet forming machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet manufacturing apparatus for extruding and forming a molten sheet extruded from a T-die into a predetermined thickness via a cast roll and a touch roll. The present invention relates to an operation control method of a sheet forming machine for always forming sheets of stable quality while preventing adverse effects due to speed differences.
[0002]
[Prior art]
Generally, a sheet manufacturing apparatus is configured by an extruder, a T-die, a sheet forming machine, a winding machine, and the like. However, at the time of forming the sheet, the molten sheet extruded from the T-die is continuously formed to a predetermined thickness through a sheet forming machine including a cast roll (first cooling roll) and a touch roll contacting with the cast roll. Then, there is known an apparatus which is configured to be sequentially wound around a winding machine.
[0003]
In the drive control of the cast roll and the touch roll that comes into contact with the cast roll in the conventional sheet manufacturing apparatus, it is configured to perform speed control on each roll, in order to prevent stress applied to the sheet due to a speed deviation between both rolls. For example, the correction of the speed command for the touch roll is periodically performed.
[0004]
That is, when the drive control of the cast roll and the touch roll is performed by speed control, a minute speed difference of the touch roll with respect to the cast roll accumulates as stress on the sheet over a long period of time, and this causes scratches and thicknesses on the sheet surface. It occurs as unevenness. For this reason, a draw control (speed ratio control) system for artificially correcting the speed command so as to keep the ratio of the rotation speed of the touch roll constant based on the rotation speed of the cast roll is adopted.
[0005]
However, the speed control for driving the cast roll and the touch roll in contact with the cast roll in the sheet forming machine is performed by a circuit configuration as shown in FIG. That is, in FIG. 3, the molten sheet 12 extruded from the T-die 10 is continuously formed to a predetermined thickness via a cast roll 14 and a touch roll 16 that comes into contact with the cast roll 14. In this case, the cast roll 14 is positioned and fixed at a predetermined position, and the touch roll 16 is configured and arranged to appropriately contact the cast roll 14 via the cylinder 18.
[0006]
The cast roll 14 and the touch roll 16 are configured to be driven by independent servo motors 20 (M1) and 22 (M2), respectively, and the servo motors 20 and 22 are respectively controlled by vector control inverter devices 21 and 23, respectively. Thus, the speed of each of the rolls 14 and 16 is controlled. The speed control value set by the main speed setting device 24 is supplied to each of the vector control inverter devices 21 and 23, and the speed control of the servo motor 22 with respect to the touch roll 16 is performed. The vector control inverter device 23 for performing the operation is configured to be able to supply the degree command value via the draw setting device 25.
[0007]
According to the speed control circuit configured as described above, the cast roll 14 performs speed control by the vector control inverter device 21 and the servo motor 20 (M1) based on the speed command value set by the main speed setting device 24. . Using the rotation speed obtained by controlling the speed of the cast roll 14 as a reference value, the draw setting device 25 is artificially adjusted so that the ratio of the rotation speed of the touch roll 16 is kept constant, and the vector control inverter device 23 and the servo motor 22 are adjusted. The speed of the touch roll 16 is controlled via (M2).
[0008]
[Problems to be solved by the invention]
However, according to the operation control method including the speed control in such a conventional sheet forming machine, the cast roll 14 and the touch roll 16 are drive-controlled by a common speed control method, and the operator controls both roll drive ammeters. Since the draw setting device 25 is adjusted while watching, a speed difference occurs between the cast roll 14 and the touch roll 16. This speed difference is caused as a set speed error generated from an electrical or mechanical factor between the roll drive current and the actual roll rotation speed. Therefore, as shown in FIG. 4, for example, when the rotation speed of the touch roll 16 is lower than the rotation speed of the cast roll 14, the rotation of the servomotor 22 becomes irregular, and the torque value rapidly increases in a cycle of 1 to 2 hours. I do. As a result, when the torque value drops sharply, the molten sheet 12 passes between the two rolls at a speed exceeding a predetermined speed, and there is a problem that scratches and thickness unevenness occur on the sheet surface with which the touch roll 16 contacts. For this reason, there has been an inconvenience that the draw setting device 25 must be periodically adjusted for the touch roll 16 to adjust its rotation speed. If the adjustment is neglected, the servomotor 22 may be burned.
[0009]
Therefore, as a result of intensive studies, the inventor of the present invention has performed a drive control on a cast roll for a molten sheet extruded from a T-die by applying a speed command set in a speed setting unit to the first motor drive control device. The speed control of the first roll drive motor is performed so that the rotation speed becomes constant via the first roll drive motor. The drive control of the touch roll is performed by adjusting the speed command set in the speed setting unit by the draw setting device and by controlling the second speed. The motor is controlled by the speed control of the second roll drive motor so that the rotation speed becomes constant through the motor drive control device, and the torque limit command set by the torque limiter is transmitted through the second motor drive control device. By performing the limit control, the speed of the touch roll is not periodically adjusted, and a stable, high-quality Have found that it is possible to achieve a long-term stable operation control of the sheet molding machine can be carried out the molding of the over bets.
[0010]
Accordingly, an object of the present invention is to add a control for limiting the torque to the drive control of the touch roll with respect to the cast roll when the molten sheet extruded from the T-die is formed by the cast roll and the touch roll contacting with the cast roll. Accordingly, it is an object of the present invention to provide an operation control method of a sheet forming machine that can form a high-quality sheet stably and easily for a long period of time without performing periodic speed adjustment.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a method for controlling the operation of a sheet forming machine according to the present invention is characterized in that a molten sheet extruded from a T-die of an extruder is cooled to a predetermined temperature by a cast roll, and the molten sheet passing through the cast roll is melted. A sheet forming machine for forming a sheet of a predetermined thickness by pressing a touch roll on the sheet, and forming the cast roll through a first motor drive control device based on a speed set value set in a main speed setter. The first roll drive motor is driven to rotate by controlling the speed, and the speed setting value of the touch roll set in the main speed setter can be adjusted by the draw setter, and the touch roll can be adjusted via the second motor drive controller. In the operation control method of the sheet forming machine configured to be rotationally driven by controlling the speed of the second roll drive motor,
A second motor drive control device that controls the drive of a second roll drive motor that rotationally drives the touch roll is provided with a speed command unit and a torque command unit, and a speed set value set in the main speed setter. Is adjustable by the draw setting device and is input to the speed command section to control the speed of the second roll drive motor, and the torque command section is capable of adjusting and setting a torque limit value to be externally operable. And performs torque limiting control of a second roll drive motor to cause the rotation speed of the touch roll to follow the rotation speed of the cast roll.
[0012]
In this case, at the time of the torque limit control of the second roll drive motor that rotationally drives the touch roll, the torque limit value set in the torque limiter can be set to a value corresponding to a mechanical loss torque value that drives the touch roll.
[0013]
Further, as the motor drive control device, a vector control inverter device or a servo motor control device can be used.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a method for controlling the operation of a sheet forming machine according to the present invention will be described in detail below with reference to the accompanying drawings in relation to an apparatus for performing the method.
[0015]
FIG. 1 is a control system diagram showing one embodiment of an operation control method for a sheet forming machine according to the present invention. The basic configuration of the sheet manufacturing apparatus for implementing this operation control method is the same as that of the conventional apparatus, and the configuration of the main control system is also the same as the configuration shown in FIG.
[0016]
In this embodiment, however, the drive control for the cast roll 14 is performed by the speed control method of the servo motor 20 as a roll drive motor using a vector control inverter device 21 as a motor drive control device as shown in FIG. Is done. In this embodiment, the speed control method of the servo motor 22 as a roll drive motor using a vector control inverter device 23 as a motor drive control device is provided for the touch roll 16 by the configuration of the control system shown in FIG. And a torque control method is applied.
[0017]
Therefore, in the present embodiment, the touch roll drive control device 30 for the servo motor 22 for controlling the drive of the touch roll 16 includes a vector control inverter device 23, a speed command unit 32, and a torque command unit 34. The speed command unit 32 includes a main speed setting unit 24 (see FIG. 3) for generating a speed command to the vector control inverter device 21 for the servo motor 20 for controlling the drive of the cast roll 14 described above. It is connected via the setting device 25. The torque command unit 34 is connected to a torque limiter 35 capable of adjusting and setting a torque limit value by an external operation.
[0018]
Next, an operation control method of the sheet forming machine based on the control system configured as described above will be described.
[0019]
First, as described above, the cast roll 14 inputs the speed set value set by the main speed setter 24 to the vector control inverter device 21 for the servo motor 20 that controls the drive of the cast roll 14, and Is set to perform speed control. Accordingly, in this case, as shown in FIG. 2, the cast roll 14 is driven at a constant rotation speed by a required torque.
[0020]
On the other hand, as shown in FIG. 1, the touch roll 16 is set by the main speed setting unit 24 to a speed command unit 32 provided in the touch roll drive control device 30 including the vector control inverter device 23. The speed setting value is input via the draw setting device 25 to set the speed of the touch roll 16 to be controlled, and the torque limiter 35 sets the torque command portion 34 provided in the touch roll drive control device 30. By inputting the set torque limit value, it is set to perform the torque limit control of the touch roll 16.
[0021]
That is, in the drive control of the touch roll 16, as shown in FIG. 2, the drive value of the touch roll 16 is controlled to be substantially constant by being limited to the torque limit value. As a result, the rotation speed of the touch roll 16 tends to swing around following the rotation speed of the cast roll 14 to which the touch roll 16 comes into contact, and the speed control of the touch roll 16 is adjusted to substantially match the rotation speed of the cast roll 14. Is achieved.
[0022]
In this case, if the torque limit value set in the torque limiter 35 is set to a value corresponding to a mechanical loss torque value for driving the touch roll 16, the rotation speed of the touch roll 16 can be extremely favorably controlled by the rotation speed of the cast roll 14. It can be made to follow and swing around.
[0023]
In this embodiment, the case where the vector control inverter device is used as the motor drive control device has been described. However, a servo motor control device may be used instead. Furthermore, although the case where a servo motor is used as the roll drive motor has been described, an induction motor or the like may be used instead.
[0024]
The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and many design changes can be made without departing from the spirit of the present invention.
[0025]
【The invention's effect】
As is clear from the above-described embodiment, the operation control method of the sheet forming machine according to the present invention is such that the molten sheet extruded from the T-die of the extruder is cooled to a predetermined temperature by a cast roll, and the cast roll is cooled. A sheet forming machine for forming a sheet of a predetermined thickness by pressing a touch roll against a passing molten sheet, and a first motor drive control device based on a speed set value set in the main speed setter for the cast roll. The first roll drive motor is rotationally driven by controlling the speed of the first roll drive motor, and the speed set value set in the main speed setter can be adjusted by the draw setter. In a method for controlling the operation of a sheet forming machine configured to be rotationally driven by controlling the speed of a second roll drive motor via A second motor drive control device that performs drive control of a second roll drive motor that rotationally drives the stitch roll is provided with a speed command section and a torque command section, and the speed set value set in the main speed setter is set to the above-described value. Adjustable by a draw setting device, input to the speed command section to control the speed of the second roll drive motor, and connect a torque limiter capable of externally operable adjustment of a torque limit value to the torque command section. By performing torque limiting control of the second roll drive motor and setting the rotation speed of the touch roll to follow the rotation speed of the cast roll, a good quality sheet having a predetermined thickness can be properly and properly formed. It can be formed stably.
[Brief description of the drawings]
FIG. 1 is a schematic system explanatory diagram showing one embodiment of a main configuration of a control circuit for performing an operation control method of a sheet forming machine according to the present invention.
FIG. 2 is a control characteristic diagram showing operation control characteristics in the sheet forming machine of the present invention.
FIG. 3 is a schematic system explanatory diagram showing a basic configuration of a sheet forming machine for controlling operation of a conventional sheet forming machine and a control circuit thereof.
FIG. 4 is a control characteristic diagram showing operation control characteristics by speed control in a conventional sheet forming machine.
[Explanation of symbols]
Reference Signs List 10 T die 12 Fused sheet 14 Cast roll 16 Touch roll 18 Cylinder 20 Servo motor (M1) (roll drive motor)
21 Vector control inverter device (motor drive control device)
22 Servo motor (M2) (Roll drive motor)
23 Vector control inverter device (motor drive control device)
24 Main speed setting device 25 Draw setting device 30 Touch roll drive control device 32 Speed command unit 34 Torque command unit 35 Torque limiter

Claims (4)

A sheet forming machine for cooling a molten sheet extruded from a T-die of an extruder to a predetermined temperature by a cast roll, and pressing a touch roll against a molten sheet passing through the cast roll to form a sheet of a predetermined thickness. The cast roll is rotationally driven by controlling the speed of a first roll drive motor via a first motor drive control device based on a speed set value set in a main speed setter, and the touch roll is driven by the touch roll. A sheet configured so that the speed set value set in the main speed setter can be adjusted by the draw setter and the second roll drive motor is rotationally driven by controlling the speed via the second motor drive control device. In the operation control method of the molding machine,
A second motor drive control device that controls the drive of a second roll drive motor that rotationally drives the touch roll is provided with a speed command unit and a torque command unit, and a speed set value set in the main speed setter. Is adjustable by the draw setting device and is input to the speed command section to control the speed of the second roll drive motor, and the torque command section is capable of adjusting and setting a torque limit value to be externally operable. And controlling the torque of the second roll drive motor to cause the rotation speed of the touch roll to follow the rotation speed of the cast roll. 2. The sheet according to claim 1, wherein a torque limit value set in the torque limiter is set to a value corresponding to a mechanical loss torque value for driving the touch roll when performing torque limit control of a second roll drive motor that rotationally drives the touch roll. Operation control method for molding machine. 3. The operation control method for a sheet forming machine according to claim 1, wherein the motor drive control device includes a vector control inverter device. 3. The operation control method for a sheet forming machine according to claim 1, wherein the motor drive control device includes a servo motor control device.

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