JPH05329916A - Controlling device of multi-layered inflation film making machine - Google Patents

Abstract

PURPOSE:To automatically and stably manufacture multi-layered inflation film having exact thickness. CONSTITUTION:An objective take-off speed calculation means 3 calculates the objective take-off speed of film on the basis of the film thickness, film width, the specific gravity of material and objective extruder output, all of which are stored in a set point storing means 5. During the running of a multi- layered inflation film making machine, a present extruder output calculating means 1 calculates the average consumptions per unit time of respective extruders in the form of present extruder outputs on the basis of measured data sent from respective measuring sensors 15. A screw motor controlling means 2 controls the rotational frequencies of the screw motors 12 of the respective extruders so as to coincide the present extruder outputs calculated by the present extruder output calculating means 1 with objective extruder outputs. Further, a pinch roll motor controlling means 4 controls pinch rolls 37 so as to coincide the present take-off speeds, which are obtained on the basis of the detection signals emitted from pinch roll revolution sensors with an objective take-off speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a multi-layer blown film manufacturing machine.

[0002]

2. Description of the Related Art In a multi-layer blown film manufacturing machine for manufacturing a multi-layer film, a plurality of extruders are simultaneously operated to extrude a plurality of kinds of synthetic resin materials to produce a multi-layered film, but a multi-layered film of good quality is produced. In order to manufacture, the thickness of each layer of the film needs to be constant.

[0003]

However, the conventional multi-layer blown film manufacturing machine is provided with a control device for controlling the screw rotation speed of each extruder so that the material extrusion amount of each layer extruder is constant. However, there is no device for controlling the extrusion amount and the film take-up speed so as to set the total thickness of the multilayer blown film to be manufactured and adjust the film thickness to the set thickness. Therefore, in the conventional manufacturing machine, when manufacturing a multi-layer blown film, the extrusion rate of each extruder cannot be accurately controlled according to the operating state, and the rotation speed of the pinch roll for film take-up is actually manufactured. Since the film thickness is manually adjusted while watching the film thickness, there is a problem that a multilayer film having an accurate thickness cannot be automatically and stably manufactured.

The present invention has been made to solve the above problems, and provides a control device for a multi-layer inflation film manufacturing machine capable of automatically and stably producing a multi-layer inflation film having an accurate thickness. The purpose is to do.

[0005]

In order to achieve the above object, the control device of the multi-layer blown film manufacturing machine of the present invention, as shown in the configuration diagram of FIG. In a control device of a multi-layer blown film manufacturing machine that extrudes through a blow head to produce a multi-layer blown film, each weighing sensor 15 that measures the weight of the material in the hopper of each extruder, and the weighing from each weighing sensor 15 Based on the data
Current extrusion rate calculation means 1 for calculating the average consumption rate per unit time of each extruder as the current extrusion rate of material, thickness of each layer of film, specific gravity of material of each layer, film width, and total material per unit time Set value storage means 5 for pre-storing the target extrusion amount of, a screw motor 12 for rotationally driving the screw of each extruder, a screw rotation sensor 35 for outputting a signal according to the rotation speed of the screw of each extruder, The screw motor 12 of each extruder so that the current extrusion amount calculated by the current extrusion amount calculation means 1 matches the target extrusion amount.
Screw motor control means 2 for controlling the number of revolutions of the pinch roll motor, a pinch roll motor 37 for rotationally driving a pinch roll for pulling the film extruded from the blow head, and a pinch roll rotation sensor for outputting a signal according to the number of revolutions of the pinch roll. 38, the target take-up speed calculation means 3 for calculating the target take-up speed of the film from the film thickness, the film width, the specific gravity of the material, and the target extrusion amount stored in the set value storage means 5, and the pinch roll rotation sensor 38. And a pinch roll motor control means 4 for controlling the pinch roll motor 37 so that the current take-up speed obtained from the detection signal coincides with the target take-up speed.

[0006]

Before the production of the multilayer blown film, the set value storage means 5 stores the thickness of each layer of the film to be produced, the specific gravity of the material of each layer, the film width, and the target extrusion amount of the entire material per unit time. To do. The target take-up speed calculation means 3 calculates the target take-up speed of the film from the film thickness, the film width, the specific gravity of the material, and the target extrusion amount stored in the set value storage means 5.

During operation of the multi-layer blown film manufacturing machine, the current extrusion amount calculation means 1 calculates the average consumption amount per unit time of each extruder as the current extrusion amount of the material based on the measurement data from each measurement sensor 15. .. The screw motor control unit 3 controls the rotation speed of the screw motor 12 of each extruder so that the current extrusion amount calculated by the current extrusion amount calculation unit 1 matches the target extrusion amount. Further, the pinch roll motor control means 4 uses the pinch roll rotation sensor 38.
The pinch roll motor 37 is controlled so that the current take-up speed obtained from the detection signal of (1) matches the target take-up speed.

[0008]

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

FIG. 2 shows a schematic construction diagram of a multi-layer blown film manufacturing machine. Reference numerals 11 and 21 are blown film extruders, and the extrusion sides of these extruders 11 and 21 are a blow head 13 through a tube. Connected to.
The blow head 13 is arranged vertically, and a pump for blowing air into the extruded film to form a tubular bubble and a blower for an air ring, that is, for cooling the air around the bubble, are provided in the blow head 13 through a pipe line. Connected by.

The extruders 11 and 21 are screw motors 1
A screw for rotating and driving the synthetic resin material by 2 and 22 is built in, and the screw is connected to the blow head 13 so as to extrude each material from the extrusion side to the blow head 13. The extruders 11 and 21 are provided with screw rotation sensors 35 and 36 that output pulse signals according to the number of rotations of the screw.

A weighing hopper 14 is disposed above the material supply port of the extruder 11 so that its weight can be measured by a weighing sensor 15 such as a load cell, and a feeder for feeding the material to the hopper above the weighing hopper 14. 16 is installed, and below the feeder 16, a shutter 17 for supplying a material that is opened and closed electromagnetically is provided.

A similar weighing hopper 24 is disposed above the material supply port of the other extruder 21 so that its weight can be measured by a weighing sensor 25 such as a load cell.
A feeder 26 for supplying the material to the hopper is installed above it, and a shutter 27 for supplying the material that is opened and closed electromagnetically is provided below the feeder 26.

Although an example in which two extruders 11 and 21 are connected to the blow head 13 has been described in the drawing, three or more extruders are installed and three or more kinds of synthetic resin materials are used for the blow head 13. It is also possible to produce a film having three or more layers by supplying the film.

Further, in the blow head, two kinds of materials supplied from two different extruders are extruded by stacking one kind of material on one side and the other kind of material on the other side like a sandwich, and extruding it. A structure in which a layer of film is extruded, or one layer of a multilayer film is a film formed of two or more materials, that is, a film of two or more materials extruded from two or more extruders. It is also possible to use special blow heads for forming the layers.

Above the blow head 13, a pinch roll 20 and a stabilizer for sandwiching a tubular film from both sides and bending it into a sheet shape and pulling it out are disposed. The pinch roll 20 is driven by a pinch roll motor 37, and a pinch roll rotation sensor 38 that generates a pulse signal according to the rotation speed of the pinch roll 20 is provided.

FIG. 3 shows a block diagram of a control device of the multi-layer blown film manufacturing machine. This control device is mainly composed of a microcomputer.
The CPU executes processing such as setting value registration, extrusion amount control, and take-up speed control in a setting registration mode and an automatic operation mode, which will be described later, based on a control program stored in the ROM 32 in advance.

Reference numeral 33 denotes a RAM capable of writing and reading at any time,
A preset value, for example, an output value corresponding to the material weight of the weighing sensor, a weighing value when opening and closing the shutter, a unit time for calculating the average value of the material extrusion amount, or each layer of the film to be manufactured The data such as the thickness, the film width, and the specific gravity of the material of each layer are stored as preset values in advance. Also,
Temporary data such as measurement data and calculation results input from the weighing sensors 15 and 25 are also stored in the RAM 33.
3 is backed up by a battery.

Reference numeral 34 denotes an input / output circuit to which the weighing sensors 15 and 25, the keyboard 18, the display 19, the shutters 17 and 27, each rotation sensor and the motor are connected. An amplifier for the sensor, an A / D converter and each motor. The drive circuit, the encoder for the keyboard, and the controller for the display are included here. The CPU 31, the ROM 32, the RAM 33, and the input / output circuit 34 are mutually connected via a common bus, and data, address signals, and control signals are mutually transmitted.

A keyboard 18 including a ten-key pad, various function keys, a manual / automatic changeover switch, and the like, and a display 19 such as a CRT or PDP are arranged on an operation panel (control panel) not shown.

The control device of the multi-layer blown film manufacturing machine may be provided with a frost line control device, a film width control device, etc. in addition to the above control system.

Next, the operation of the control device of the above-mentioned multi-layer blown film manufacturing machine will be described.

First, when the power is turned on, the CPU 31 performs an initial setting to initialize various registers, and then selects a registration mode to display a product type setting screen on the display unit 19.

Then, the operator operates the keyboard 18 to input and register values such as the thickness and width of the film to be manufactured, the specific gravity of the material, and the extrusion amount on the screen.

That is, as shown in the flow chart of FIG. 4, the operator inputs the product type number and order number of the film to be manufactured, and then the thickness of each layer of the film is
For example, as shown in FIG.
007 mm, the second layer by the extruder 21 is 0.007 mm, the third layer by the third extruder (not shown) is 0.006 mm, and the specific gravity of the material for each extruder (specific gravity of each layer material) Also, a value such as the film width is input (step 100). These setting data are displayed on the screen and stored in the RAM 33.

Next, in step 110, the CPU 31 calculates the film thickness (0.02 mm in this case) from the thickness of each layer registered above, and displays and stores this value on the screen. This automatically registers the film thickness.

Next, in step 120, the operator operates the keyboard 18 to input the target extrusion rate per unit time (for example, 60 Kg / h) of all extruders. Then CP
U31 calculates the target extrusion amount of each layer, that is, each extruder, from the data of the thickness of each layer of the film already registered and the specific gravity of the material of each extruder (specific gravity of each layer material),
This value is displayed and stored on the screen (step 13).
0). As a result, the target extrusion rate of each layer is automatically registered.

Next, the CPU 31 at step 140,
From the above registered data, the target extrusion rate of all extruders ÷
The target take-off speed (m / min) is calculated using the formula [2 × film width × (thickness of each layer × total value of specific gravity)], and this value is displayed on the screen and stored. As a result, the target take-up speed of the film is automatically registered.

When one layer of the multi-layer film is formed of two or more kinds of materials, that is, two or more kinds of materials extruded from two or more extruders, the ratio% of the width of the layer is as shown in FIG. Enter the settings in the appropriate fields. In addition, for example, when two kinds of materials supplied from two different extruders are extruded, another one kind of material is laminated on both sides of one layer and extruded so as to form a three-layer film. When extruding,
In the case where the material of the third layer is extruded from the first extruder, the code 1 is entered in the third extruder column to indicate this.

Then, in addition to the registration of the setting data as described above, necessary setting values such as the film production planning length, the unit winding length, and the length correction value are input to complete the setting registration.

Next, each of the extruders 11 and 21 is started to start a preparatory operation, and the tubular film extruded from the extruders 11 and 21 is removed from the stabilizer by adjusting the screw rotation speed and the film take-up speed. Pass it between the pinch rolls 20,
Air is blown into the tube to form bubbles above the blow head 13.

When a weighing switch (not shown) is turned on during the above-described preparatory operation, the CPU 31 causes the CPU 31 of FIG.
From step 100 to step 110, the weighing data from the weighing sensors 15 and 25 is fetched at regular intervals (for example, every second), and the current value is subtracted from the previous value,
Calculate the material consumption of each extruder 11, 21 per second,
These are sequentially stored in the buffer memory, and for example, the average consumption per minute is calculated every second, and the consumption is stored and displayed as the current extrusion amount.

The material from the feeders 16 and 26 has the minimum weight (for example, 2) of the weighing hoppers 14 and 24.
(kg) or less, the shutters 17 and 27 open,
When the weight exceeds a maximum value (for example, 20 kg), the shutters 17 and 27 are controlled to be closed, and the material is automatically supplied. The feeders 16 and 2
When the material is charged from 6, the above-mentioned weighing operation is stopped for 10 seconds, for example.

At the stage of such a preparatory operation, the screw speeds of the screws of the extruders 11 and 21 and the pinch roll 20 are gradually increased by the manual switch operation of the operator. When the switch is operated, the CPU 31 determines in step 130 that there is an adjustment operation, and determines in step 130.
To 140, the rotation speeds of the screws of the extruders 11 and 21 and the pinch roll 20 are adjusted (accelerated) to a state close to the actual film production operation according to the operation of these switches.

Then, when the screw rotation speeds of the extruders 11 and 21 have reached appropriate speeds and the film take-up speed has reached near the set target take-up speed, when the automatic switch is turned on, the routine proceeds from step 150 to step 160. ,
Similarly to the above, the current consumption amount of the material is calculated based on the hopper weight data sent from the weighing sensors 15 and 25, and for example, the average consumption amount per minute is calculated every second, and the consumption amount is calculated as follows. The extrusion amount is stored and displayed.

Next, in step 170, control data for acceleration or deceleration is generated and output so that the current extrusion amount of the material calculated in step 160 matches the target extrusion amount calculated at the time of setting registration.

That is, first, with respect to the rotation speed of the screw, the average rotation speed of the screw at a constant time interval is calculated based on the detection signals (pulse signals) from the screw rotation sensors 35 and 36. Then, the command rotation speed is calculated from the arithmetic expression of target extrusion rate × average screw rotation rate ÷ current extrusion rate, and the control data of the command rotation rate is output to the drive circuit of the screw motor to drive the extruders 11 and 21. The screw motors 12 and 22 are controlled and driven.

Next, in step 180, the current takeoff speed of the film is calculated. Here, the film take-up speed (m / min) is calculated from the detection signal (pulse signal) output from the pinch roll rotation sensor 38.

Then, in step 190, the current film take-up speed calculated above is compared with the set take-up target take-up speed, and control data is created so as to match the present take-up speed with the target take-up speed. Output to the drive circuit of the motor 37. As a result, the pinch roll 20 is drive-controlled so as to draw the multilayer blown film at the target drawing speed.

Thereafter, when the production start switch is not turned on, the process returns to step 160, and steps 160 to 190 are executed as described above, the current extrusion amount of the material and the film transaction speed are repeatedly calculated, and the current extrusion amount of the material. Is changed, the rotation control of the screw is performed so as to match the current extrusion amount with the target extrusion amount, and the pinch roll 20 is controlled so as to match the current film drawing speed with the target drawing speed.

In this way, when the operation of the multi-layer blown film production machine becomes stable and a good blown film is produced, the production start switch is turned on to start the actual production run. Here, steps 220 to 230 are executed to start measuring the production length of the film. The production length of the film is measured by counting the pulse signals from the pinch roll rotation sensor 38. Then, during the production operation, step 160
~ 240 are repeatedly performed, and while controlling the extruders 11, 21, the pinch roll 20, etc., a multilayer inflation film having a constant thickness is stably produced. When the film reaches the unit take-up length, the take-up roll of the take-up machine is automatically replaced, and when the total production length of the film reaches the production plan length, the operation is terminated.

[0041]

As described above, according to the control device of the multi-layer blown film manufacturing machine of the present invention, the target take-up speed calculating means is such that the film thickness, the film width and the material stored in the set value storing means are set. The target take-up speed of the film is calculated from the specific gravity and the target extrusion rate, and the current extrusion rate calculation means calculates the average consumption rate per unit time of each extruder based on the measurement data from each measurement sensor as the current extrusion rate of the material. Calculate as Then, the screw motor control means controls the rotation speed of the screw motor of each extruder so that the current extrusion rate calculated by the current extrusion rate calculation means matches the target extrusion rate, and the pinch roll motor control means controls the pinch roll motor control means. Since the pinch roll motor is controlled to match the current take-up speed obtained from the detection signal of the roll rotation sensor with the target take-up speed, a multilayer blown film having an accurate thickness is automatically and stably manufactured. can do.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram of a multilayer blown film manufacturing machine showing an example of the present invention.

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

FIG. 4 is a flowchart of registration processing.

FIG. 5 is an explanatory diagram of a product type setting screen.

FIG. 6 is a flowchart of an extrusion amount / take-up speed control process.

[Explanation of symbols]

1-current extrusion amount calculation means, 2-screw motor control means, 3-target take-up speed calculation means, 4-pinch roll motor control means, 5-set value storage means, 12-screw motor, 15-metering sensor, 35- Screw rotation sensor, 37-pinch roll motor, 38-pinch roll rotation sensor.

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Claims (2)

[Claims] Claim: What is claimed is: 1. A synthetic resin material is extruded from a plurality of extruders through a blow head to measure a weight of the material in a hopper of each extruder in a control unit of a multi-layer blown film manufacturing machine for manufacturing a multi-layer blown film. And the current extrusion rate calculation means for calculating the average consumption rate per unit time of each extruder as the current extrusion rate of the material based on the measurement data from the respective measurement sensors, the thickness of each layer of the film, and each layer Specific gravity of material, film width,
And a set value storage means for storing in advance the target extrusion amount of the entire material per unit time, a screw motor for rotating the screw of each extruder, and a screw rotation for outputting a signal according to the rotation speed of the screw of each extruder. A sensor, a screw motor control unit that controls the rotation speed of the screw motor of each extruder so that the current extrusion amount calculated by the current extrusion amount calculation unit matches the target extrusion amount, and the screw head is extruded from the blow head. A pinch roll motor that drives a pinch roll that pulls in the film, a pinch roll rotation sensor that outputs a signal according to the number of revolutions of the pinch roll, a film thickness and a film width stored in the set value storage means, A target take-up speed calculation means for calculating a target take-up speed of the film from the specific gravity of the material and the target extrusion rate; Control device with a multilayer inflation film making machine equipped with pinch roll motor control unit, the controlling the pinch rolls motor so that the current take-up speed obtained from the detection signal of the roll rotation sensor coincides with the target take-up speed. 2. When the target extrusion amount data of the entire material is input, the target extrusion of the extruder for each layer is performed by using the thickness of each layer of the film and the specific gravity data of the material of each layer which are already stored in the set value storage means. The control device for a multi-layer blown film manufacturing machine according to claim 1, further comprising calculation means for calculating the amount.