JPH06297568A - Controller of inflation film manufacturing device - Google Patents

Abstract

PURPOSE:To provide a controller for an inflation film manufacturing machine which can perform a stabilized manufacture of a film of a preset thickness by simplifying the constitution without using a metering hopper and controlling only a haul-up speed. CONSTITUTION:A pinch roll revolution sensor 6 which generates as many pulse signals as those corresponding to the number of revolutions of pinch rolls 4, a wind-up revolution sensor 9 which detects revolutions of a wind-up part of a wind-up machine 8 which winds film which has been hauled-up by the pinch rolls 4, and generates signals at every specified revolution are provided, and an operation means 10 of the film thickness and a pinch roll motor control means 20 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower film production machine controller for producing a tubular blown film.

[0002]

2. Description of the Related Art A blown film manufacturing machine continuously extrudes a thermoplastic resin from an inflation die by a screw extruder while continuously supplying a gas into the tubular film to create bubbles, which are continuously formed. Although it is an apparatus for manufacturing a laminated tubular film while taking it off, a control apparatus for controlling the take-up speed of the blown film in order to keep the thickness of the blown film constant is conventionally known.

This type of control device measures the consumption time per unit weight of the material in the material hopper extruded by the screw extruder, and according to the consumption time, the rotation speed of the pinch roll for taking the film, that is, the take-up speed. However, it is difficult to measure the consumption of resin material accurately, and it is possible to accurately control the film take-up speed according to the consumption of the material extruded by the extruder, that is, the extrusion amount of the material. It was difficult to do.

[0004]

Therefore, conventionally, in Japanese Patent Laid-Open No. 3-261538, etc., the weight of a material supply hopper is measured at regular time intervals, and the measured value is used as the material consumption amount at constant time intervals. Inflation that calculates the average consumption of material per unit time and controls to match the take-up speed of the pinch roll to the optimum take-up speed of the film calculated from the data of the average consumption, film thickness, width, etc. A control device for a film manufacturing machine has been proposed.

However, although this control device can take a film at an optimum speed according to the amount of material consumed and stably produce a film having a set thickness and width,
In order to measure the material consumption, it is necessary to provide a special-purpose weighing hopper with a weighing sensor at the material supply port of the extruder, which complicates the structure of the control device and increases the manufacturing cost. there were.

The present invention has been made in order to solve the above-mentioned problems, and can simplify the structure without using a weighing hopper, and by controlling only the take-up speed, a film having a preset thickness can be obtained. It is an object of the present invention to provide a control device for an inflation film manufacturing machine, which is capable of stably manufacturing a film.

[0007]

In order to achieve the above object, a control device for an inflation film manufacturing machine according to the present invention has a tubular shape extruded from an extruder of an inflation film manufacturing machine as shown in FIG. A pinch roll motor 5 for driving the pinch roll 4 for pulling the film of
A pinch roll rotation sensor 6 that generates a pulse signal of a number corresponding to the number of rotations of the pinch roll 4 and rotation of a winding unit of a winder 8 that winds the film taken up by the pinch roll 4 are detected, and a constant rotation is detected. The winding rotation sensor 9 that generates a signal for each time, and the pulse signal that is generated from the pinch roll rotation sensor 6 while the winding portion of the winding machine 8 rotates a predetermined number are counted,
The film thickness calculating means 10 calculates the circumference of the winding section from the number of pulses and the radius of the winding section, and calculates the increase in the radius of the winding section that occurs during one rotation of the winding section as the film thickness. And a deviation between the film thickness calculated by the film thickness calculation means 10 and a preset thickness setting value, and a pinch roll motor control for controlling the speed of the pinch roll motor 5 so that the deviation becomes zero. Means 20
And are configured.

[0008]

When the blown film manufacturing machine is automatically operated, the pinch roll 4 takes up the tubular film extruded from the extruder, and the winder 8 takes up the film taken up by the pinch roll 4. . In the meantime, the pinch roll rotation sensor 6 generates a pulse signal of a number corresponding to the number of rotations of the pinch roll 4, the winding rotation sensor 9 detects the rotation of the winding portion of the winder 8, and outputs a signal at every constant rotation. To occur.

Then, the film thickness calculating means 10 counts the pulse signals generated from the pinch roll rotation sensor 6 while the winding portion of the winder 8 rotates for a predetermined time, and the circle of the winding portion is calculated from the pulse number. Find the circumference and the radius,
The increase in the radius of the winding section that occurs during one rotation of the winding section is calculated as the film thickness.

The pinch roll motor control means 20
Is the deviation between the film thickness calculated by the film thickness calculation means 10 and the preset thickness setting value, and controls the speed of the pinch roll motor 5 so that the deviation becomes zero. The thickness of the film is controlled to the set value.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a schematic configuration diagram of an inflation film manufacturing machine. First, an outline of an inflation film manufacturing machine will be described with reference to this figure. Reference numeral 1 is an inflation film extruder, which has a built-in screw which is driven to rotate by a screw motor to extrude a synthetic resin material.

A feeder for feeding the material is provided above the material feeding port of the extruder 1, and the feeding side of the extruder 1 is
A blow head 2 with a built-in die is mounted vertically. The blow head 2 is a pump for blowing air into the extruded film to form a tubular bubble, for an air ring, that is, for cooling the air around the bubble. Blower is connected.

Above the blow head 2, there are provided a stabilizer 3 and a pinch roll 4 for sandwiching the tubular film F from both sides and bending it into a sheet to take it up. The pinch roll 4 is driven by a pinch roll motor 5, and the pinch roll 4 is provided with a pinch roll rotation sensor 6 that generates a number of pulse signals according to the rotation speed of the pinch roll 4.

The film taken up by the pinch roll 4 passes through the plurality of guide rolls, the dancer roll 7 and is sent to the winder 8 where it is wound up.

The winding machine 8 is rotationally driven by a motor,
The rotation speed of the motor is controlled so that the position of the dancer roll 7 is constant, and the film F is wound with a constant tension. Further, the winding machine 8 is provided with a winding rotation sensor 9 for detecting the rotation of the winding roll, and for example, outputs one pulse signal for each rotation of the winding section.

FIG. 3 shows a block diagram of a control unit of the blown film manufacturing machine. This control unit is mainly composed of a microcomputer,
Reference numeral 11 denotes a CPU, which calculates the thickness of a film to be manufactured as described below based on control program data stored in the ROM 12 in advance, and controls the take-up speed so that the film thickness matches the set value. Reference numeral 13 denotes a RAM that can be written and read at any time, and stores measured data input from various sensors, or various preset values and constants, numerical values necessary for calculation, calculation results, and the like. This RAM1
3 is backed up by a battery.

Reference numeral 14 is an input / output circuit to which various sensors and motors are connected, and includes a sensor amplifier, a D / A converter, a motor driving servo amplifier, and the like. CPU11,
The ROM 12, RAM 13, and input / output circuit 14 are connected to each other via a common bus, and data, address signals, and control signals are mutually transmitted.

The pinch roll motor 5, the pinch roll rotation sensor 6, the winding rotation sensor 9, the operation switch group 15 and the display 16 on the operation panel are the input / output circuit 14 as well.
Connected to.

As shown in FIG. 4, on the operation panel of the control unit, as a display 16, a film thickness set value display section for displaying the set film thickness, a manufactured film thickness and set value are displayed. Deviation display section for displaying the deviation of the film, a thickness correction value display section for displaying the set film thickness correction value, and a take-up speed display section for displaying the take-up speed of the film. Further, as the operation switch group 15, there are provided an input switch for inputting the respective set values, a manual switch for manual operation, an automatic switch for automatic operation, a speed increasing switch for increasing / decreasing the take-up speed during manual operation, a deceleration switch, and the like. . Further, an indicator lamp is provided which lights up when the film take-up speed is stable.

The calculation of the film thickness T executed by the CPU 11 uses the equations of T = (R1−R0) / 2n R1 = L1 / 2π, L1 = P1C R0 = L0 / 2π and L0 = P0C Is done.

Here, R1 is the radius of the winding portion at this time, and R0 is
Is the radius of the last winding section, n is the number of windings for one measurement of the winding machine, L1 is the circumference of this winding section, L0 is the circumference of the last winding section, and P1 is this time Is the number of pulses of the pinch roll rotation sensor 6 and P0 is the number of pulses of the previous pinch roll rotation sensor 6. C is a film length conversion constant, which is proportional to the film feed length per pulse of the pinch roll rotation sensor 6 and is calculated from the equation C = H · π / 1200 × 4. H is the diameter of the pinch roll 4.

The measurement of the pulse (count of the number of pulses) from the pinch roll rotation sensor 6 which indicates the take-up length (winding length) of the film is performed every time the winder 8 makes one rotation, and is temporarily stored in the RAM. Remembered. Then, the radius of the winding portion of the winder 8 is calculated by calculating the average winding length (circumferential length) of the film from the average value of the pulses for n rotations (for example, 10 rotations) for each rotation. Similarly, the film thickness T is calculated by calculating the average value of n rotations for each rotation of the winding unit.

Although not shown in FIG. 2,
The blown film manufacturing machine may be provided with a frost line control device, a film width control device, and the like in addition to the above control system, if necessary.

Next, the operation of the control device having the above configuration will be described with reference to the flowchart of FIG.

Prior to the operation of the blown film manufacturing machine, the thickness of the film to be manufactured (for example, 20 μm) is displayed on the film thickness set value display section of the operation panel of the control unit.
m) is set using the input switch. Initially, the thickness correction value is set to zero.

Then, the extruder 1 is started and the manual switch is operated to enter the preparation (setup) for manufacturing, and while the pinch roll motor 5 is in an adjustable state, the tubular shape extruded from the extruder 1 is set. The film F is passed between the stabilizer 3 and the pinch rolls 4, passed through the guide rolls, the dancer rolls 7, and guided to the winder 8. During this time, above the extruder 1, air is sent to the inside and outside of the tube from the pump and blower to create bubbles above the blow head 2.

While the manufacturing machine is being preliminarily operated in this way, the pulses sent from the pinch roll rotation sensor 6 are counted, the take-up speed (m / min) of the film F is calculated, and it is displayed on the take-up speed display section. To be done. Also, the winder 8 is 1
Each time the film is rotated, the thickness T of the film F is calculated by the pulse measurement value and the above equation.
And the set value are calculated and displayed on the thickness deviation display section.

In this state, the operator adjusts the film take-up speed to the optimum speed (for example, 50 m / min) by operating the speed increasing switch or the speed decreasing switch on the operation panel. When the film take-up speed becomes the optimum speed and the film take-up speed becomes stable, the operator operates the automatic switch to start the automatic operation.

When the automatic operation is started, the process proceeds from step 100 to step 110 in the flowchart of FIG.
The PU 11 counts the pulses sent from the pinch roll rotation sensor 6, calculates the take-up speed (m / min) of the film F, and displays it on the take-up speed display unit.

Next, in step 120, the thickness T of the film F is calculated. The film thickness T is calculated by using the formula such as T = (R1−R0) / 2n shown above.
The average value for n rotations is calculated for each one rotation of the winding section.

Then, in step 130, the deviation between the calculated film thickness T and the preset film thickness setting value is calculated, and the deviation is displayed on the thickness deviation display section.

Next, in step 140, the rotational speed of the pinch roll motor 5 is controlled so that the above deviation becomes zero. That is, when the measured film thickness is thicker than the set value, the speed of the pinch roll motor 5 is increased to increase the film take-up speed, and when the measured film thickness is thinner than the set value, the pinch roll motor 5 Control is provided to reduce the speed to reduce the film take-up speed. Such speed control of the pinch roll motor 5 is gradually performed stepwise.

Then, in the state where the deviation of the film thickness is sufficiently small, and good film production is possible,
A production start switch (not shown) is pressed to start production (step 150), and the winding length (production length) of the film F is
Measurement is performed by integrating the pulses generated from the pinch roll rotation sensor 6 (step 160). During the production of the film, the steps 110 to 170 are repeatedly executed, the film thickness is calculated as described above, and the pinch roll motor 5 is controlled so that the deviation between the film thickness and the set value becomes zero. , The film take-off speed is controlled. Therefore, even when the amount of material extruded changes due to changes in the operation of the extruder 1, the take-up speed is controlled so as to keep the film thickness constant, and a film having a set thickness is stably manufactured. To be done.

Since the film is manufactured in a tubular shape and wound on the winder in a double-layered state, the radius of the winding portion increases due to the air layer entering between the films, and The film thickness decreases due to the elongation of the film due to the tension during winding.

Therefore, if necessary, the thickness of the produced film is measured before starting the production of the film,
If the measured value is different from the thickness of the film to be produced, the thickness correction value is set so as to eliminate the difference. When this thickness setting value is set, this correction value is added when the thickness deviation is calculated, and a film having a more accurate thickness is produced.

[0037]

As described above, according to the control device of the blown film manufacturing machine of the present invention, the rotation of the pinch roll and the rotation of the winder are detected to calculate the thickness of the film, and the thickness of the film is calculated. Since the take-up speed of the pinch rolls is controlled so as to match the height with the set value, it is not necessary to provide the extruder with a weighing hopper, and the configuration of the control device can be simplified. Further, even for a ready-made blown film manufacturing machine, it is possible to stably manufacture a film having a set thickness simply by mounting a control device which has a simple structure and is relatively inexpensive.

[Brief description of drawings]

FIG. 1 is a configuration diagram of the present invention.

FIG. 2 is a schematic configuration diagram of an inflation film manufacturing machine showing an embodiment of the present invention.

FIG. 3 is a block diagram of a control device of the blown film manufacturing machine.

FIG. 4 is a front view of an operation panel.

FIG. 5 is a flowchart showing the operation of the control device.

[Explanation of symbols]

 1-Extruder, 4-Pinch Roll, 5-Pinch Roll Motor, 6-Pinch Roll Rotation Sensor, 8-Winding Machine, 9-Winding Rotation Sensor, 10-Film Thickness Calculating Means, 20-Pinch Roll Motor Control means.

Claims (1)

[Claims] 1. A pinch roll motor that drives a pinch roll that pulls a tubular film extruded from an extruder of an inflation film manufacturing machine, and a pinch that generates a number of pulse signals corresponding to the number of rotations of the pinch roll. A roll rotation sensor, a winding rotation sensor that detects a rotation of a winding unit of a winder that winds a film pulled by the pinch roll, and generates a signal at every constant rotation, and a winding of the winder. The pulse signal generated from the pinch roll rotation sensor is counted during the predetermined rotation of the winding section, the circumference of the winding section is calculated from the number of pulses, and the radius thereof is calculated, and while the winding section makes one rotation. A film thickness calculating means for calculating the resulting increase in radius of the winding portion as a film thickness, and a film thickness calculated by the film thickness calculating means and a preset thickness A deviation of the value, the control device of the inflation film manufacturing machine, characterized in that it comprises a pinch roll motor control means for controlling the speed of said pinch rolls motor such deviation becomes zero, the.