JPH047122A - Control device of film width spreading position of inflation film producing machine - Google Patents

Abstract

PURPOSE:To make it possible to easily set reference width spreading position optimum in response to the kind of film to be produced by a method wherein width spreading position data, which is detected under the condition that the film width spreading position stabilizes at optimum position on the detecting position of a photoelectric detector, are stored as reference position data. CONSTITUTION:When an inflation film producing machine is started, a photoelectric detector 30 detects film width spreading position every certain period of time so as to input detection signal to a controlling circuit. Under the condition that the film width stabilizes and the film width spreading position stabilizes at optimum position on the detecting position of a photoelectric detector 30, an operator turns on a reference position setting switch 29 so as to store the width spreading position data detected at that time is stored as reference position data in a reference position storing means 8. After that time, a blower controlling means 9 compares the width spreading position data detected with the photoelectric detector 30 with the reference position data stored in the reference position storing means 8 so as to bring the film width spreading position to the reference position by controlling a blower 18 on the basis of the result of the compression.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is a film manufacturing machine for manufacturing a cylindrical blown film. The present invention relates to a film widening position control device for controlling a widening position to a set position.

<Prior art> A blown film manufacturing machine continuously extrudes thermoplastic resin from an inflation die into a cylindrical film using a screw extrusion method, supplies gas into the cylindrical film to create bubbles, and continuously extrudes the film. A stacked tube-shaped film is produced while being removed.

The width of the film to be manufactured varies depending on the amount of gas (air) supplied into the cylindrical film (bubbles), so the width of the cylindrical film can be adjusted by adjusting the amount of air supplied into the cylindrical film. is set to the set value, but if the bottom of the bubble, that is, the position where the cylindrical film widens, changes up or down, the volume of the bubble changes, so even if the amount of air supplied into the cylindrical film is controlled. Also, the film width cannot be controlled to the set value. Therefore, it is necessary to control the widening position of the cylindrical film (the position near the frost line below the bubble) to a predetermined constant position.

<Problems to be Solved by the Invention> To this end, conventionally, as described in Japanese Patent Publication No. 59-40608, Japanese Patent Application Laid-Open No. 58-78725, etc., the frost line or the width of the film has been widened using a charge detector. A control device is known that controls the frost line to a constant position by detecting the position and adjusting the amount of air supplied around the bubble according to the detection signal.

However, this type of conventional frost line control device has a charge detector of various sizes (for example, a film width of 2
0 C11 to 100 ca+) film width cannot be detected, and the optimal frost line or bubble widening position depends on the environmental temperature at the time of film production, the thickness of the film to be produced, the film width, etc. The problem is that it is extremely difficult to set the optimal width expansion position depending on the type of film being manufactured, as the setting device that sets the width expansion position is simply a setting device that sets numerical values. There was a flash.

The present invention has been made to solve the above problems, and can be used in film manufacturing machines of various film widths, and can easily determine the optimal standard widening position of the film depending on the type of film, etc. An object of the present invention is to provide a film widening position control device for a blown film manufacturing machine that can be set and controlled.

Means for Solving the Problems> In order to achieve the above object, the film widening position control device of the present invention optically controls the widening position of the cylindrical film extruded from the blow head, as shown in FIG. In order to detect The blower 18 blows air, the reference position setting switch 29 sets the film width reference position, and when the reference position setting switch 29 is turned on when the film width expansion position is at the optimal position during preparatory operation of the manufacturing machine. , a reference position storage means 8 that stores the current widening position data detected by the photoelectric detector 30 as reference position data; and a blower control means 9 that compares the stored reference position data and controls the blower 18 so that the film widening position becomes the reference position based on the comparison result.

Prior to operation of the manufacturing machine, the positions of the light receiver and the light emitter of the photoelectric detector 30 are adjusted vertically or horizontally or horizontally depending on the thickness, film width, etc. of the film to be manufactured.

The blown film manufacturing machine is started, and the extruder, pinch rolls, etc. are manually adjusted to bring the film take-up speed close to the actual film production speed. The photoelectric detector 30 detects the widening position of the film at regular intervals, and its detection signal is input to the control circuit.

Then, when the film width is stabilized and the film widening position is stabilized at the optimum position above the detection position of the charging detector, the operator turns on the reference position setting switch.

Then, the detected widening position data at that time is stored in the reference position storage means 8 as reference position data. Thereafter, the blower control means 9 compares the widening position data detected by the photoelectric detector 30 and the reference position data stored in the reference position storage means 8, and based on the comparison result, the widening position of the film is set to the reference position. The blower 18 is controlled so that the position is the same.

<Example> Embodiments of the present invention will be described below based on the drawings.

First, the schematic structure of a blown film manufacturing machine will be explained with reference to FIG. 2. Reference numeral 11 is a blown film extruder, which has a built-in screw that is rotationally driven by a screw motor 12, and is capable of extruding synthetic resin material supplied from a material supply hopper 13. extrude. A blow head 15 containing a die is vertically attached to the extrusion side of the extruder 11 via a pipe 14. In this Blow Herad 15,
A pump (not shown) for blowing air into the extruded cylindrical film 25 to create a tubular bubble is connected to a pipe line, and a blower 18 for blowing cooling air to the outer periphery of the film 25 is connected. Conduit connected. This blower 18 is rotationally driven by a blower motor 19, and the rotation of the blower motor 19 is controlled by a control device described later.

A photoelectric detector 30 is installed above the blow head 15 in order to detect the widening position (lower part of the bubble) where the extruded cylindrical film 25 widens.

This photoelectric detector 30, as shown in FIGS. 3 and 4,
At the widening position of the film, a large number of horizontal light beams are generated vertically at regular small intervals, and transmission or non-transmission of each light beam is detected. That is, the photoelectric detector 3o includes a mounting body 3 in which a light receiver 31 and a light emitter 32 arranged on both sides of the film 25 can be adjusted vertically and horizontally.
This is the structure attached to 3.34.

The support stands on both sides that support the mounting body 33 , 34 have completely the same structure, and the mounting body 33 , 34 is supported by the guide shaft 36 of the vertical moving part 35 so as to be able to slide up and down, and with respect to the screw shaft 37 . The female screw portions are screwed together, and the screw shaft 37 is rotated to be vertically movable. Further, the vertical moving section 35 is supported so as to be movable in the horizontal direction by a guide shaft 39 of the horizontal moving section 38, and is movable in the horizontal direction by the rotation of the screw shaft 40 by screwing the female threaded part onto the screw shaft 40. will be placed. Then, the horizontal moving section 38 is fixed on the support leg 41.

The light receiver 31 and the light emitter 32 are, for example, as shown in FIG.
Eight phototransistors or photodiodes are arranged in two vertical rows at 10 mm intervals, and each row is shifted vertically by 5 cm, so that each light emitter/receiver 31, 32 does not interfere with each other, 16 in total. The horizontal light beams are arranged at regular intervals of, for example, 5 square meters so that they are generated on one vertical line at the widening position of the film 25, as shown in FIG.

Further, in order to prevent mutual interference, the light projectors and receivers are arranged alternately, and the light projecting and receiving operations of each light beam are sequentially performed using a scanning method. If the film is translucent, ultraviolet rays, infrared rays, etc. other than visible light are used to ensure detection of the film. The film widening position is detected from the reception state of each light beam as the boundary position between the light beam where the film is detected and the light beam where the film is not detected.

Such a photoelectric detector 30 can be moved according to the width of the film to be manufactured. For example, if the film width becomes large, the photodetector 30 may be shifted upward at the outer periphery of the light receiver 31 and the emitter 32, and if the film width becomes smaller. For example, the receiver 31 and the emitter 32
Adjust the position by turning screw shafts 3 and 40 so as to shift the position downward on the inner circumferential side.

Above the blow head 15, a stabilizing plate 20 and a pinch roll 21 are disposed for sandwiching a tubular film from both sides and folding it into a sheet shape to take it off.
The film 25 taken up by 1 passes through a guide roll 22 and a width measuring device 26 that measures the film width.
It passes through the second pinch roll 23 and is wound up by a winding machine 24.

As shown in FIG. 6, the film widening position control device to which the blower motor 19 and photoelectric detector 30 are connected is composed of a microcomputer as a main part, and a CPU 50.
measures the widening position of the film based on the program data stored in advance in the ROM 51, and controls the rotational speed of the blower motor 29, that is, the amount of air blown by the blower 28, according to the widening position, so that the film widening position is the set standard. In addition, the ROM 51 contains calculation formulas, etc. for calculating the blower air volume and motor speed command signal from the measured widening position data and the set reference position data. is stored as fixed data.

CPO50% ROM51, RAM52, input/output circuit 53
are interconnected via a common bus, and the photoelectric detectors 30,
A blower motor 19 and a reference position setting switch 29 are connected to an input/output circuit 53. The input/output circuit 53 includes a light projection drive circuit for a light projector, a conversion circuit that converts a received light signal into a pulsed signal, a drive control circuit for the blower motor 19, and the like. The reference position setting switch 29 is provided on a control panel or the like that can be easily operated by an operator while driving.

Next, the operation of the film widening position control device having the above configuration is as follows.
First, the extruder 1 will be explained using a flowchart in FIG.
1 is started, preparations for production are started, the molten tubular film is extruded from the blow head 15, and the tubular film 25 is pushed out from the stabilizer plate 20 while manually adjusting the screw motor 12, pinch roll 21, etc. It is passed between pinch rolls 21 and guided to a winder 24. Then, drive the pump to blow from the rad 15 to the cylindrical film 25.
Air is blown into the film 25 to form a film bubble upward, and the blower 18 is operated to blow clearing air from the blow head 15 toward the upper part of the outer periphery of the film 25.

In this state, the operator manually operates the switch to
The rotational speed of the screw, pinch roll, etc. of the extruder 11 is gradually increased to bring the film take-up speed close to the actual film production speed. Then, the film width becomes stable,
The expanded position of the film 25 becomes stable on the detection position of the photoelectric detector 30.

In such an operating state, the CPU 50 takes in data on the widening position of the film 25 obtained by driving the photoelectric detector 30 in step 100, and then in step 110.
Then, it is determined whether the reference position setting switch 29 has been turned on. When the operator turns on the switch 29 to set the current widening position of the film as the reference position, the process proceeds to step 120, where the widening position data at that time is stored in the RAM 82 as reference position data.

Next, in step 130, the CPU 50 again drives the charge detector 30 and takes in the data on the widening position of the film 25 obtained, and in step 140, the CPU 50 compares the current widening position data with the reference position data, Step 150
Then, it is determined whether the difference between the widening position data and the reference position data is greater than or equal to a preset value (for example, 25 mm), and if the difference is smaller than the set value, the process returns to step 130 and the photoelectric detector is again The film widening position data from 30 is taken in.

Then, steps 130 to 150 described above are repeatedly executed, and when the difference between the widening position data of the film 25 detected by the charge detector 30 and the reference position data exceeds a preset value, steps 150 to 160 are performed. Then, the rotation speed of the blower motor 19 is controlled and the film 2 is
The amount of air blown to the outer periphery of 5 is adjusted to control the current widening position to match the reference position.

That is, when the detected film widening position is larger (higher) than the reference position, the rotational speed of the blower motor 19 is increased and the air flow rate of the blower 18 is increased, and the film widening position is lowered downward. , if the detected film widening position is lower than the reference position, the number of revolutions of the blower motor 19 is decelerated and the amount of air blown by the blower 18 is reduced;
Raise the film widening position upward.

Then, return to step 130 again, and step 130
By repeating the process in step 160 as described above, control is performed so that the film width expansion position becomes the set reference position based on the width expansion position detected by the photoelectric detector 30. If you want to change the standard film widening position for some reason during automatic operation, switch the production machine from automatic operation to manual operation, and when switching to manual operation, erase the memory of the standard position and change the pinch rolls and extruder. While adjusting the operation manually, adjust the film widening position to a stable and optimal position, and at that point,
The reference position setting switch 29 is turned on again to store new reference position data.

<Effects of the Invention> As explained above, according to the film widening position control device of the blown film manufacturing machine of the present invention, the widening position of the cylindrical film extruded from the blow head is optically detected, and the detection Since we have installed a photoelectric detector with a photodetector and emitter that can be adjusted by moving vertically and horizontally, if you are trying to manufacture different types of films with different widths and thicknesses using the same manufacturing machine, you will need to check the type of film. The photoelectric detector can be easily adjusted to detect the optimal widening position depending on the

In addition, a reference position setting switch is provided to set the film width reference position, and when the film width is stabilized during the preparatory operation stage and the film width expansion position is stabilized at the optimum position above the detection position of the photoelectric detector, the operator can Since the reference position setting switch is turned on and the detected widening position data at that point is stored in the reference position storage means as reference position data, the operator can
The optimal widening reference position can be easily set according to the type of film to be manufactured.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the present invention, Figs. 2 to 7 show an embodiment of the present invention, Fig. 2 is a schematic block diagram of a blown film manufacturing machine, and Fig. 3 is a front view of a charging detector. , Fig. 4 is a plan view of the arrangement of the charge detector, Fig. 5 is an explanatory diagram of the arrangement of the light beam of the photoelectric detector, Fig. 6 is a block diagram of the control circuit, and Fig. 7 is a flowchart of widening position control. 8...
Reference position storage means, 9... Blower control means, 18... Blower, 29... Reference position setting switch, 30... Photoelectric detector. Figure 1 Patent applicant 16m Figure Figure Figure Figure

Claims (1)

[Claims] In order to optically detect the widening position of the cylindrical film extruded from the blow head, there is provided a photoelectric detector including a detection light receiver and a light emitter that can be adjusted vertically and horizontally. , a blower for blowing cooling air to the outer periphery of the cylindrical film extruded from the blow head; a reference position setting switch for setting a film widening reference position; is at the optimum position and the reference position setting switch is turned on, reference position storage means for storing the current widening position data detected by the photoelectric detector as reference position data; The widening position data detected by this method,
Blower control means for comparing the reference position data stored in the reference position storage means and controlling the blower so that the film widening position becomes the reference position based on the comparison result. Film widening position control device for manufacturing machines.