JPH0586902B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus capable of producing a cylindrical inflation film without uneven thickness.

[Conventional technology]

When producing a thin cylindrical inflation film by drawing molten resin through a narrow lip in a film molding die, the thickness of the film may vary.

To remove uneven thickness during melt extrusion film molding, there are two methods: mechanical control by changing the lip spacing, and thermal control by changing the lip temperature distribution. .

Mechanically adjusting the lip spacing to remove uneven thickness has a limited accuracy, takes time to adjust, and has poor responsiveness.

On the other hand, it is already well known that uneven thickness can be removed by changing the temperature distribution of the lip. It is not easy to properly remove uneven thickness.

[Problem to be solved by the invention]

The factors that cause uneven thickness in the manufacturing process of synthetic resin films are complex, and the main parameters are mechanical structural dimensions and shapes, and parameters such as temperature, drawing speed, and cooling air speed. It can be divided into

Thickness unevenness caused by parameters including time elements such as speed and wind speed, and by including temperature, which changes from moment to moment, in the parameters, although time is not directly included in the parameters, is It is difficult or impossible to remove by changing the size or shape of the molding equipment.

On the other hand, in the production of inflation films, it is not possible to stop the film from being pulled out even during the adjustment of the film thickness and uneven thickness, and the films produced during the adjustment period become defective.

Therefore, it is desirable that the time required to adjust the uneven thickness and the response time of the adjusted parameters to the finished product be as short as possible.

In particular, unless the initial settings of the film manufacturing apparatus are quickly completed at the start of operation so that films of desired specifications can be manufactured in a short period of time, yields will be poor and the price of the film will increase.

Further, when producing a wide variety of products in small quantities, the specifications of the film may be changed without stopping the film manufacturing apparatus. Even in such cases, it is desirable to be able to quickly perform adjustments such as removing uneven thickness with simple operations so that a product with the desired specifications can be quickly obtained.

For this reason, conventional equipment that removes uneven thickness by installing a large number of heaters around the lip of a film forming die has the effect of removing uneven thickness in principle, but In order to correct the uneven thickness according to the degree of uneven thickness, it is necessary to promptly control a large number of heaters as required, and it is desired to put such a means into practical use.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a film molding die having an annular die lip and provided with a plurality of heating means and temperature measuring means near the die lip, and a molten resin discharged from the die lip. A film pulling means that pulls out the film at a required speed, and a film thickness of a ring-shaped sample film cut at appropriate lengths in the direction perpendicular to the film drawing direction, are continuously measured along the cut edge of the film. a film thickness measuring means for measuring the film thickness;
Based on the film thickness data measured by the film thickness measuring means, the position data of the film thickness data is made to correspond to the die lip periphery, and the film thickness data is made to correspond to a plurality of heating means provided near the die lip. and a calculation means for calculating an electrical value for electrically controlling the amount of heat generated by each heating means in order to equalize the film thickness of the film based on the film thickness data corresponding to each heating means; production of a cylindrical inflation film characterized by comprising a heating amount control means for controlling the heating amount of each heating means based on the electrical control value corresponding to each heating means determined by Equipment is provided.

[Effect]

The thickness of the completed film is continuously measured in the cut direction of the film using a film thickness measuring means.The measured values are input into a computer, and based on the film thickness measurement values, uneven thickness areas and die lips of the film are determined. The correspondence of neighboring heating elements is calculated and determined, and the amount of heat generated by the corresponding heating element is suitably controlled according to the amount of uneven thickness of the uneven thickness portion.

〔Example〕

FIG. 1 shows an embodiment of the apparatus of the present invention.

1 is an extruder, 2 is a film molding die, 3 is
Bubble film drawn from die 2, 4
is Nitzprol for pulling out film 3,
Reference numeral 5 indicates a plurality of heating elements provided near the die lip 2a of the die 2, and reference numeral 6 indicates a temperature measuring element for measuring the temperature near any one of the plurality of heating elements 5.

7 is a calculation means for controlling the amount of heat generated by each heating element 5 as required. Around the calculation means 7, a film thickness measuring means 8 is provided which measures the thickness of the completed film 3a obtained by folding the film 3 which has been cooled as required into a flat shape with the nip roll 4, and inputs the measured data to the calculation means 7. and display the required data of the calculation means 7 or display the required instructions.
A CRT monitor device 9 and a key device 10 for inputting required function codes, numerical data, etc. to the calculation means 7 are provided.

Each heating element 5 can individually control the amount of heat generated, and in the embodiment, a ceramic sheath type electric heater is used. This heating element 5 is provided around the outer periphery of the annular die lip 2a, with the elements closely approaching each other.

The temperature measuring element 6 is arranged close to one of the heating elements 5 and measures the temperature in the vicinity of the heating element 5 at an absolute level. In the embodiment, four temperature measuring elements 6 are arranged at equal intervals, and each of these temperature measuring elements 6 measures the temperature of the heating element 5 closest to the temperature measuring element 6, and divides the total heating element 5 into four equal parts. It also measures the representative temperature of the heating element group.

A film 3 is formed by drawing out the molten resin from the die 2, and the film thickness of the formed film is measured by the film thickness measuring means 8 at the point where the film is divided in a direction perpendicular to the drawing direction of the film, and the measured value is measured. is input to the calculation means 7.

In the calculation means 7, the film thickness measurement data at each measurement position is made to correspond to the plurality of heating elements 5 provided at the periphery of the die lip 2a, and the film thickness data corresponding to each heating means are made equal. An electrical control value for controlling heat generation of the heating element 5 is calculated.

By drawing out the molten resin from the die 2 in which each heating element 5 is controlled by the electric control value determined in this way and forming it into a film 3,
A cylindrical inflation film of uniform thickness is obtained.

FIG. 3 is a longitudinal sectional view of the die 2 showing a state in which the heating element 5 and the temperature measuring element 6 are installed near the die lip 2a.

A mandrel 2c is fitted in the center of the die body 2b, and a lip adjustment ring 2c is fitted on the outer periphery of the upper end 2d of the mandrel 2c at an interval that forms the die lip 2a. An air ring 2f for air cooling the film 3 pulled out from the die lip 2a is provided above the lip adjustment ring 2e.

In inflation molding, an inside mandrel that generates the internal pressure of the film 3, a guide that guides the outer periphery of the film 3, etc. are provided, but since these are not deeply related to the essence of the present invention, they are not shown in the drawings. Omitted.

A band heater 2g is wound around the outer periphery of the die body 2b and lip adjustment ring 2e, and the temperature of the die 2 is measured by a temperature measuring element 2h provided on the die body 2b and controlled as required.

The lip adjustment ring 2e is centered with respect to the mandrel 2c by an adjustment screw 2i, so that the spacing between the die lips 2a remains uniform over the entire circumference.

Each of the heating elements 5 is embedded in the lip adjustment ring 2e toward the axis of the die 2 at a location close to the die lip 2a.

The four temperature measuring elements 6 are embedded in the lip adjustment ring 2e close to the heating element 5. The temperature measuring element 6 may be a thermocouple, a platinum resistor, or any other temperature-sensitive type, and a thermocouple is used in the embodiment.

In the embodiment, four temperature measuring elements 6 are used, but this is because it is suitable for a case where the heating element 5 is an electric heater and its calorific value is controlled by proportional power control. However, as will be described later, in this proportional control, it is not essential to know the temperature of the heating element 5.

However, by knowing the temperature of the die lip 2a, other factors that cause uneven thickness can be compensated over time using the temperature as a parameter, so four temperature measuring elements 6 are provided.

It is also possible to control the amount of heat generated by each heating element 5 by temperature.
One temperature measuring element 6 is provided for each.

Rather than controlling the amount of heat generated by proportionally controlling the electric power of the electric heater, which is the heating element 5, controlling the temperature of the electric heater provides feedback control and generally has higher responsiveness.

Note that the control and responsiveness of the heating element 5 will be described later.

The calculation means 7 is comprised of a microcomputer having a microprocessor unit (hereinafter referred to as MPU) 11, as shown in FIG.

The film thickness measuring means 8 measures the film thickness of a ring-shaped sample film 3b obtained by cutting the completed film 3a in a direction perpendicular to the drawing direction at appropriate lengths (approximately 10 to 20 mm) in the drawing direction. The measurement is carried out continuously in the direction perpendicular to the drawing direction, that is, along the cut.

That is, the film thickness measuring means 8 sequentially measures the film thickness while moving the ring-shaped sample film 3b along the cut, and also uses the film thickness measurement data and the measurement in the direction orthogonal to the direction in which the film is pulled out. The film thickness measurement data is input into the calculation means 7 in correspondence with the position data.

The film thickness measuring means 8 is a rotary encoder 8a.
a drive roller 8b, a guide roller 8c,
The sample film 3b is wound around an annular tape running means consisting of a tension roller 8d, and the sample film 3b is run along the cut, and the rotary encoder 8a detects measurement position data P in the running direction. ing.

A film thickness detection sensor 8e and a light projector 8f are provided between the drive roller 8b and the guide roller 8c. The film thickness detection sensor 8e continuously measures the film thickness of the running sample film 3d, and when this measurement output is an analog output, the A/D converter 12
It is converted into digital film thickness data D via .

The position data P and film thickness data D are taken into the MPU 11, and are either table-like one-dimensional array data in which the position data P is associated with addresses, or separate consecutive addresses with the position data P and film thickness data as a pair. The data is stored in a required working memory M1 as two-dimensional array data corresponding to .

Position data P of the ring-shaped sample film 3b
will circulate endlessly, so set a reference point in advance,
Define the start and end of position data.

If the fold line 3c formed when the film 3 is folded by the nip roll 4 is made to correspond to the opening of the die lip 2a, the fold line 3c will always be in a constant position.

That is, when the contact surface of the nip roll 4 is projected onto the die 2 directly below, it becomes
This becomes the line X', and the intersection of this line X-X' and the die lip 2a is the position where the fold 3c is pulled out.

The fold 3c also remains on the sample film 3b, and one of the folds 3c is used as a reference point.

When sampling the sample film 3b, mark one of the folds 3c, for example, the X' side, as a reference point, and
Marks such as arrows are also placed on the direction of withdrawal of the book so that the front and rear directions can be determined later.

As a result, the positional data P of the sample film 3b is divided into required positional data P during one rotation of the fold 3c' marked as the reference point.

The starting point and ending point of the position data P obtained in this way correspond to the fold line 3c', and also correspond to the opening periphery of the die lip 2a.
It also corresponds to each heating element 5 provided close to a.

FIG. 5 shows the position of the fold 3c and the positional relationship of each heating element 5 with respect to the position data P of the sample film 3b and the corresponding film thickness data D.

Note that each heating element 5 has a fold 3 with a mark attached thereto.
From the reference point X′ from which part c′ was extracted,
Element numbers N are assigned in order in a counterclockwise direction.

As shown in FIG. 5, the element number N is attached.
Measured film thickness data D for each heating element 5
corresponds to this, and thereby, to remove uneven thickness,
The required electrical control value for each heating element 5 can then be calculated.

For example, the film thickness reference value (hereinafter referred to as a set value) required for the completed film 3a is compared with the film thickness data D, and the deviation thereof is determined.

This shows that the heating elements 5 corresponding to the film thickness data D that match the set value, for example, the seventh to twelfth heating elements 5 in FIG. 5, can be kept in the current control state.

When the film thickness data D is larger than the set value, the heating element 5 corresponding to the part where the thickness is large;
For example, the amount of heat generated by the first to sixth heating elements 5 may be increased to raise the temperature of the die lip 2a near the heating elements 5, thereby reducing the film thickness during film formation.

The degree of increase in the amount of heat generated by the heating element 5 at this time is directly proportional to the deviation value of the film thickness data D corresponding to the heating element 5 from the set value.

In addition, when the film thickness data D is smaller than the set value, the heating element corresponding to the part with insufficient thickness, for example, the 15th to 25th heating element 5, is heated by reducing the amount of heat generated. The temperature of the die lip 2a near the element 5 may be lowered to increase the film thickness during film formation.

In this case, as in the case of an increase in the amount of heat generated, the degree of decrease in the amount of heat generated by the corresponding heating element 5 is directly proportional to the deviation value of the film thickness data D corresponding to the heating element 5 from the set value.

Note that since the deviation value itself from the reference value takes a positive or negative value, the amount of heat generated by the heating element 5 is generally said to be directly proportional to the difference between the film thickness data D corresponding to the heating element 5 and the set film thickness value. be able to.

Thereby, the amount of heat generated by each heating element 5 necessary to remove uneven thickness can be determined not at an absolute level but at a relative level.

That is, each heating element 5 when the sample film 3b was molded (hereinafter this point will be referred to as the present).
For example, if the heating element 5 is an electric heater, the power value of the increase or decrease from the current value of power consumption, regardless of the actual amount of power consumption. The calorific value is calculated as follows.

When controlling the power of an electric heater, when the temperature coefficient of the resistance of the electric heater is zero or extremely small, the power consumption, that is, the amount of heat generated, is exactly proportional to the square of the current or voltage, so proportional control is easy. Therefore, there is no need for temperature compensation.

As described above, the heat generation adjustment data Δd for each heating element 5 corresponding to each heating element 5 is based on the set value C according to the reference film thickness, the position data P, and the film thickness data D.
According to the position data P, the MPU 11 performs
It is obtained by calculating Δd=D−C.

Position data P created by this MPU11
Based on the table that corresponds to the addition/subtraction data Δd,
On the position data P, the element number N attached to each heating element 5 is associated, and a heating element control table Tx is created in which the element number N is associated with the adjustment data Δd. This control table Tx is temporarily stored in the working memory M1.

The calculation means 7 is a nonvolatile memory M2, such as a ROM or backed up by a battery.
A memory area such as RAM is provided, and a heating element reference control table Tf is stored in this memory M2.

The reference control table Tf is designed to prevent thickness deviations caused by the peculiarities of the die determined in advance during manufacturing of the die 2 and when adjusting the interval between the die lips 2a, such as deviations in the spacing between the die lips 2a and variations in the heat generation characteristics of each heating element. This is data from which components are removed.

For example, during initial adjustments such as test runs,
The heating of each heating element 5 is controlled to a constant value close to the center of the control range, and the film specifications and operating conditions are set to standard conditions, and the film 3 is formed, and the sample obtained at that time. The aforementioned control table T _X is created based on the measurement data of the film 3b.

Next, changes are made to the control values for each heating element 5 based on the control table _TX . That is, addition/subtraction data Δd corresponding to each element is added to the initial constant reference value of each element.

After the control of each heating element 5 is changed to change the amount of heat generated, the next sample film 3b is collected after waiting for thermal equilibrium of the changed heating element 5.

This adjustment is repeated in the same way until the sample film 3b has no uneven thickness or until the uneven thickness becomes smaller than a required reference value.

This repeated adjustment by collecting the sampling film 3b is essentially feedback control in automatic control. The amount of feedback corresponds to the addition/subtraction data Δd, and if this amount of feedback is negative feedback, that is,
If it acts in the direction of removing the uneven thickness, the uneven thickness component will converge to zero over a long period.

As a result of the above adjustment, when the uneven thickness is removed and a film 3a with a uniform thickness can be obtained, the control table Tx at that point is set as the control reference table Tf, and it is stored in the nonvolatile memory M2. do.

In addition, in the control reference table Tf, the part related to the control data d of each heating element 5 is a relative value with respect to a reference value similar to the addition/subtraction data Δd, or
It may be any absolute level value corresponding to the amount of heat generated (or power consumption) of the heating element.

The reference control table Tf may be created when assembling the die 2 and when adjusting the lip interval of the die lip 2a.

At the start of normal film forming, each heating element 5 is first controlled by the standard control Cheeble Tf.
is controlled. However, there are many parameters that cause uneven thickness, and it is complicated because it is related to temperature. Furthermore, when producing a film with specifications different from those used when creating the reference control table Tf, uneven thickness may occur.

Therefore, at the start of film forming, after the die 2 is preheated by the reference control table Tf and the film 3 is in a state where it can be stably formed after the die 2 is in thermal equilibrium, the film forming is started and the sample film 3b is Extract the sample film 3b
As described above, the film thickness is measured by being attached to the film thickness measuring means 8, and position data P and film thickness data D are collected.

Using this position data P and film thickness data D, the amount of variation in the reference control table Tf is calculated, and the amount of heat generated by each heating element 5 is quickly reset.

Heating element number N calculated by MPU11
and the corresponding control data d are converted into a digital-to-analog (hereinafter abbreviated as D/A) converter 1.
3 and a power control section 14, each heating element 5 is controlled.

Further, the measured value of each temperature measuring element 6 is determined by the temperature measuring section 1.
5 and an analog-to-digital (hereinafter abbreviated as A/D) converter 16, the data is taken into the MPU 11 at a proper time.

FIG. 6 shows an example in which the electrical power of the electric heater of each heating element 5 is controlled by proportional control, and FIG.
An example will be shown in which each heating element 5 is subjected to feedback control using a temperature measuring element 6' paired with it.

To explain FIG. 6, the power control section 14
is equipped with a plurality of power control circuits 14a for each heating element 5 to control the power consumption of each heating element 5.

The power control circuit 14a controls the power consumption of the output load according to the value of the input voltage, and if the input voltage is constant, the power consumption of the output load (electric heater) is also constant, and the input voltage is When changing, the output power also changes in proportion to the magnitude of the input voltage.

Such a power control circuit 14a can be achieved by a circuit that squares the input voltage by using an electric heater of the load whose temperature coefficient of resistance is extremely small or zero, as described above.

Moreover, power control is also possible in time division control using thyristors. In this case, the corresponding linearity between control data d and power consumption is MPU1
This can be handled by the operation in 1. This linearity is not required.

By the former square circuit or by control data d
will be squared in advance on the MPU 11 side and then proportional control applied to the power control circuit 14a will be explained.

From the MPU 11, control data d (or 2
The multiplied data d ² ) is sent to the D/A converter 13,
This control data d is taken into the latch circuit 13a of the circuit that controls the heating element 5 of the number N in accordance with the heating element number N corresponding to the control data d.

The captured control data d is sent to the latch circuit 13
control data d sent from a to the D/A conversion circuit 13b and D/A converted by the D/A conversion circuit 13b;
is sent to the power control circuit 14a.

The configuration of the D/A converter 13 is just one example, and may include a sample-and-hold circuit that pre-processes the D/A conversion and then holds the analog signal. In this case, the D/A converted analog signal can be distributed to sample-and-hold circuits corresponding to each number N by a multiplexer such as an analog switch.

Each latch circuit 13a specifies the heating element number N by the port address of the MPU 11,
The control data d can also be directly taken in from the bus line of the MPU 11.

FIG. 7 shows another embodiment of the power control unit 14, and the power circuit 14a may be the same as that in FIG.

The temperature measuring element 6' is provided in a one-to-one correspondence with each heating element 5, and measures the temperature of each heating element 5.

The temperature detected by the temperature measuring element 6' is transferred to the amplifier 14b.
is converted into a temperature signal via the comparator 14
input to the control input terminal of c.

Control data from the D/A conversion circuit 13b similar to that described above is input to the reference signal input terminal of the comparator 14c. This allows comparator 1
4c controls the power circuit 14a so that the control data d from the D/A conversion circuit 13b and the temperature signal output from the amplifier 14b are equal.

The power circuit 14a in FIG. 7 is controlled by the output of the comparator 14c, so when the control data d is changed to a new one, the output is greatly varied to improve responsiveness and control the heating element 5. The temperature is quickly controlled according to the data d.

In the power circuit 14a shown in FIG. 6, when the control data d is changed to a new one, the amount of change in output power changes only by the magnitude of the addition/subtraction data Δd.
Therefore, responsiveness is poor.

In order to solve this problem, when changing the control data d, depending on the magnitude of the adjustment data Δd, differential waveform components with a large rise and a required attenuation rate are superimposed in the calculation of the MPU 11 to improve the response. All you have to do is increase it.

On the other hand, the temperature measuring element 6' in FIG. 7 is connected to the amplifier circuit 14b.
The accuracy of the absolute level of the temperature signal obtained by the above method, that is, the accuracy of matching of mutual reference levels, may be lower than that related to general temperature control.

For example, a temperature measuring element 6' corresponding to each heating element 5
There is no problem even if there is an offset error of several degrees Celsius in the relative error of the detected temperature characteristics.

That is, the adjustment data Δd for removing the uneven thickness component occurring in the sample film 3b is a relative temperature difference component that should be adjusted with respect to the detected temperature when the sample film 3b was produced, and is a relative temperature difference component that should be adjusted. Absolute level error in detected temperature does not affect control.

This also applies to the power circuits 14a in FIG. 6, and there is no need to match the absolute levels of the input/output characteristics between the power circuits 14a.

However, during the first sampling, the influence of variations in the input/output characteristics of each power circuit 14a in FIG. 6 or the detected temperature characteristics in FIG. 7 appears.

That is, even if each D/A conversion circuit 13b outputs the same value as a reference value, due to variations in the input/output characteristics or detected temperature characteristics,
The amount of heat generated by each heating element 5 varies, and as a result, the uneven thickness of the first sample film 3b is affected.

When the amount of heat generated by the heating element 5 is changed, it takes time for the heating element 5 to reach thermal equilibrium with the changed amount of heat. This time is the response time, and in order to shorten it, the differential control and feedback control described above are required.

However, the die lip 2a has a large heat capacity, and even if the above control is performed, it will take some time to reach a stable period.

The time from when the calorific value is changed until the thermal stability period is reached is proportional to the degree of change in the calorific value. That is, it is proportional to the magnitude of the absolute value (|Δd|) of the addition/subtraction data Δd, and if the addition/subtraction data Δd varies widely, and the fluctuation value is large, it will take time to adjust the uneven thickness removal.

The heating reference control table Tf includes components for eliminating variations in input/output characteristics and detected temperature characteristics, and at the beginning of normal film forming, each heating element 5 is controlled by this control table Tf. ,
After the die 2 has been sufficiently preheated and thermally stabilized, film forming is started.

In this way, a high-quality film with less uneven thickness can be quickly produced by adjusting the first sample extraction at the start of a normal operation.

During daily film manufacturing, necessary data such as film thickness, film width, film drawing speed, etc. are input from the key device 10 to the MPU 11.

Once a high-quality film can be stably obtained by adjusting the uneven thickness removal, it is confirmed by collecting a sample film 3b as necessary, and the control data of each heating element 5 at that time is recorded. d,
It is associated with the heating element number N and stored in the non-performance memory M3 as a control table Tl according to the film specifications.

Further, each time the film specifications are changed, the control tables are stored as control tables T2, T3, etc., and even if the film specifications are the same, they are updated to the latest one.

Control tables T1 and T2 according to film specifications
... is selected based on film specification data input to the MPU 11 at the beginning of operation, and controls each heating element at the start of operation instead of the heating element reference control table Tf.

Thereby, the film thickness can be controlled according to the film specifications using the latest control tables T1, T2, . . . . The nonvolatile memory _M3 that stores the control tables _T1 , _T2 ...Tn may be a removable IC card. When using an IC card, one IC card has one control table, and one IC card has one control table.
Individual IC cards, film specifications and special orders from suppliers,
A plurality of control tables may be recorded in association with specific elements such as specifications.

〔Effect of the invention〕

Since the thickness of the film is continuously measured and controlled in a direction perpendicular to the feeding direction, it is possible to obtain a film with a uniform thickness with little thickness deviation.

Since the adjustment to remove uneven thickness is performed quickly, there are fewer defective products molded during the adjustment, and the yield is improved.

We can quickly respond to changes in film specifications,
Therefore, it becomes easy to produce a wide variety of films in small quantities, and no skill is required to adjust the film thickness.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an enlarged plan view of the die taken along the line - in FIG. 1, and FIG. 3 is an enlarged longitudinal sectional view taken along the line - in FIG. FIG. 4 is a block diagram of the calculation means shown in FIG. 1, and FIG. 5 is a graph of the position data P of the sample film and the corresponding film thickness data D, and the graph of each heating element provided at the periphery of the die lip opening. FIG. 6 is a block diagram showing an embodiment of the power control section shown in FIG. 4;
FIG. 7 is a block diagram showing another embodiment of the power control section of FIG. 4. 1... Extruder, 2... Film forming die, 2
a...Die lip, 2b...Die body, 2c...
Mandrel, 2d... Upper end, 2e... Lip adjustment ring, 2f... Air ring, 2g... Band heater, 2h... Temperature measuring element, 2i... Adjustment screw, 3... Film, 3a... Completed film ,2
b...Sample film, 3c...Fold, 4...
Nipprol, 5... Heating element, 6... Temperature measuring element, 7... Calculating means, 8... Film thickness measuring means, 8a
... Rotary encoder, 8b ... Drive roller, 8c ... Guide roller, 8d ... Tension roller, 8e ... Film thickness detection sensor, 8f ... Light emitter, 9 ... CRT monitor device, 10 ... Key device 10 , 11...MPU, 12...A/D converter,
13...D/A converter, 13a...latch circuit,
13b...D/A conversion circuit, 14...Power control unit, 14a...Power control circuit, 14b...Amplifier, 14c...Comparator, 15...Temperature measurement unit, 16...Analog-digital conversion unit, d …
...Control data, D...Film thickness data, P...Position data, Δd...Adjustment data, d2...Data, N
...Element number, M1...Working memory, M2, M3
...Non-performance memory, tx...Heating element control table, Tf...Heating element reference control table, Tl~Tn
...control table.

Claims (1)

[Scope of Claims] 1. A film molding die having an annular die lip and provided with a plurality of heating means and temperature measuring means near the die lip; and a membrane for continuously measuring the film thickness of a ring-shaped sample film cut at appropriate lengths in the direction perpendicular to the film drawing direction along the cut edge of the film. A thickness measuring means; Based on the film thickness data measured by the film thickness measuring means, the positional data of the film thickness data is made to correspond to the die lip periphery and is connected to a plurality of heating means provided near the die lip. In addition to matching the film thickness data, based on the film thickness data corresponding to each heating means, calculation is performed to calculate the electrical value for electrically controlling the amount of heat generated by each heating means in order to equalize the film thickness of the film. and a heating amount control means for controlling the amount of heat generated by each heating means based on the electrical control value corresponding to each heating means determined by the calculation means. Flation film manufacturing equipment.