JP7249192B2 - Inflation molding equipment - Google Patents

Description

The present invention relates to inflation molding equipment.

Inflation molding is known, in which melted resin is extruded from a die into a tubular shape, air is blown into the inside of the tube to expand it, and a thin film is formed. Conventionally, there has been proposed a technique for keeping the thickness of the film within a target range by adjusting the lip width as an adjusting element.

WO2017/090694

In inflation molding there is a desire to have as little adjustment of the adjustment element as possible. According to Patent Document 1, since the thickness of the film can be made relatively uniform in the circumferential direction, it is possible to form a film roll body with few or small bumps and dents, but the above-mentioned demand cannot be taken into consideration.

The present invention has been made in view of these circumstances, and one exemplary object of certain aspects thereof is to provide a film roll having relatively few or few bumps or depressions while providing a relatively small amount of adjustment of the adjustment elements. To provide an inflation molding device capable of forming a body.

In order to solve the above problems, an inflation molding apparatus according to one aspect of the present invention is an inflation molding apparatus that molds a tubular film, folds it into a flat film, and winds up the flat film to form a roll body. A controller is provided for determining the amount of adjustment of the adjustment element for adjusting the thickness of the tubular film based on the information regarding the thickness of the flat film.

Arbitrary combinations of the above constituent elements, and mutual substitution of the constituent elements and expressions of the present invention in methods, devices, systems, etc. are also effective as aspects of the present invention.

According to the present invention, it is possible to provide an inflation forming apparatus capable of forming a film roll body with relatively few or small bumps and dents while reducing the amount of adjustment of the adjusting elements.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the inflation molding apparatus which concerns on 1st Embodiment. 2(a) and 2(b) are diagrams showing the cross-sectional shape of the film. 2 is a block diagram schematically showing the functions and configuration of the control device of FIG. 1; FIG. It is a figure which shows schematic structure of the inflation molding apparatus based on the modification of 2nd Embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent constituent elements, members, and processes shown in each drawing are denoted by the same reference numerals, and duplication of description will be omitted as appropriate. Moreover, the embodiments are illustrative rather than limiting the invention, and not all features and combinations thereof described in the embodiments are necessarily essential to the invention.

FIG. 1 shows a schematic configuration of an inflation molding apparatus 1 according to the first embodiment. The inflation molding device 1 includes a die 2 , a cooling device 3 , a pair of stabilizers 4 , a take-up device 5 , a thickness measuring section 6 and a control device 7 .

A molten resin supplied from an extruder (not shown) is extruded from a ring-shaped discharge port 2 a formed in the die 2 . At this time, air is jetted into the extruded resin from an air jet port 2b formed in the center of the die 2, forming a tube-shaped film (hereinafter also referred to as a "bubble").

The die 2 is configured to be able to adjust the width of the discharge port 18a (hereinafter referred to as lip width) at each position in the circumferential direction by an adjustment element (not shown). By adjusting the lip width, the thickness of the film at the corresponding position can be adjusted.

A cooling device 3 is arranged above the die 2 . The cooling device 3 cools the bubbles by blowing cooling air.

A pair of stabilizers 4 are arranged above the cooling device 3 and guide the bubbles to the take-up machine 5 . The take-up machine 5 is arranged above the stabilizer 4 . Take-up machine 5 includes a pair of pinch rolls 38 . A pair of pinch rolls 38 are driven by a motor (not shown) to rotate and pull up the guided bubble to flatly fold it. Hereinafter, the flatly folded film is also referred to as a "flat film". The winder 20 winds the flat film to form the film roll body 11 .

A thickness measuring unit 6 is arranged between the cooling device 3 and the stabilizer 4 . The thickness measuring unit 6 measures the thickness of each position in the circumferential direction of the bubble while rotating around the bubble. Thickness data measured by the thickness measuring unit 6 is transmitted to the control device 7 .

The control device 7 is a device for integrally controlling the inflation molding device 1 .

2(a) and 2(b) are diagrams showing the cross-sectional shape of the film. FIG. 2(a) is a cross-sectional view of a bubble, and FIG. 2(b) is a cross-sectional view of a flat film. The bubble has a substantially circular cross section as shown in FIG. 2(a). The flat film, as shown in FIG. 2(b), is a two-ply film in which bubbles are folded at circumferential positions of 0° and 180°. That is, the flat film is a two-ply film in which the portion of the bubble in the circumferential position of 0° to 180° and the portion of the bubble in the circumferential position of 360° to 180° overlap, more specifically, the bubble in the circumferential position θ. It is a two-ply film in which each portion and each portion at the circumferential position (360°-θ) are overlapped.

FIG. 3 is a block diagram schematically showing the functions and configuration of the control device 7. As shown in FIG. Each block shown here can be implemented in terms of hardware by elements such as the CPU of a computer or a mechanical device, and in terms of software is implemented by a computer program or the like. It depicts functional blocks that Therefore, those skilled in the art will understand that these functional blocks can be realized in various ways by combining hardware and software.

The control device 7 includes a communication unit 40 that executes communication processing with the thickness measurement unit 6 according to various communication protocols, a U/I unit 42 that receives operation input by the user and displays various screens on the display unit, A data processing unit 46 that executes various data processing based on data acquired from the communication unit 40 and the U/I unit 42, and a storage unit 48 that stores data referenced and updated by the data processing unit 46. ,including.

Storage unit 48 includes a thickness storage unit 64 . The thickness storage section 64 stores the thickness data transmitted from the thickness measurement section 6 .

The data processing unit 46 includes a receiving unit 50, a determining unit 52, and an operation control unit 54.

The receiving unit 50 receives thickness data from the thickness measuring unit 6 . The receiving unit 50 causes the thickness storage unit 64 to store the received thickness data.

The determination unit 52 determines the adjustment amount of the lip width at each position in the circumferential direction based on the measured values of the thickness of the bubble at each position in the circumferential direction, which are stored in the thickness storage unit 64 . The determining unit 52 particularly adjusts the lip width at each position in the circumferential direction so that the thickness of the bubble at each position in the circumferential direction is within the allowable range and that no large bumps or dents are formed on the outer periphery of the film roll body 11. to decide.

Here, if the bubble thickness is uniform in the circumferential direction, the film roll body 11 can be formed without large bumps or dents on the outer periphery. If the film thickness T (see FIG. 2(b)) is uniform in the width direction, the film roll body 11 can be formed without large bumps or dents on the outer circumference. Considering this, in the present embodiment, the amount of adjustment of the lip width at each position in the circumferential direction is determined as follows in order to reduce the amount of adjustment.

(1) The thickness of the two parts that overlap when the bubble is folded, that is, the measured value t _θ (see FIG. 2A) of the thickness of the bubble at the circumferential position (θ) and the circumferential position (360°- θ) when the measured bubble thickness t _360°-θ (see Fig. 2(a)) is equal to the bubble reference thickness (target thickness or average thickness in the circumferential direction)

In this case, the sum of the thicknesses of the two overlapping portions, i.e., the thickness of the flat film corresponding to the two portions, is equal to the standard thickness of the flat film (twice the standard thickness of the bubble). In this case, the determining unit 52 determines that the lip width adjustment amount corresponding to the two overlapping portions is zero (the lip width is not adjusted).

(2) When the thickness of the two parts that overlap when the bubble is folded is both thicker than the standard thickness of the bubble

In this case, the sum of the thicknesses of the two overlapping portions, that is, the thickness of the flat film corresponding to the two portions is thicker than the reference thickness of the flat film. In this case, the determination unit 52 adjusts only the lip width corresponding to one of the two portions to make the total thickness equal to the standard thickness of the flat film.

Preferably, the determining unit 52 compares the difference between the two portions with respect to the bubble reference thickness, and then adjusts only the lip width corresponding to the one with the greater difference from the bubble reference thickness, and adds them together. Make the thickness equal to the reference thickness of the flat film. For example, if one thickness is the bubble reference thickness +0.2 mm and the other thickness is the bubble reference thickness +0.3 mm, the determination unit 52 determines that the other thickness, which is significantly different from the reference thickness, is the reference thickness - Determine the corresponding lip width adjustment to be 0.2 mm.

Note that the determination unit 52 may adjust only the lip width corresponding to the smaller difference from the bubble reference thickness. +0.3 mm, the adjustment amount of the corresponding lip width may be determined so that the one thickness having a smaller difference from the reference thickness becomes the reference thickness -0.3.

(3) When the thickness of the two parts that overlap when the bubble is folded is both thinner than the standard thickness of the bubble

In this case, the sum of the thicknesses of the two overlapping portions, that is, the thickness of the flat film corresponding to the two portions is thinner than the reference thickness of the flat film. In this case, the determination unit 52 adjusts only the lip width corresponding to one of the two portions to make the total thickness equal to the standard thickness of the flat film.

Preferably, the determination unit 52 adjusts only the lip width corresponding to the larger difference from the standard thickness of the bubble out of the two parts, and makes the total thickness equal to the standard thickness of the flat film. For example, if one thickness is the reference thickness −0.2 mm and the other thickness is the reference thickness −0.3 mm, the determination unit 52 determines that the other thickness, which is significantly different from the reference thickness, is the reference thickness +0.2 mm. The amount of adjustment of the corresponding lip width is determined so that

Note that the determining unit 52 may adjust only the lip width corresponding to the smaller difference from the reference thickness of the bubble. If it is −0.3 mm, the adjustment amount of the corresponding lip width may be determined so that the one thickness with the smaller difference from the reference thickness becomes the reference thickness +0.3 mm.

(4) When the thickness of one of the two parts that overlap when the bubble is folded is thicker than the standard thickness of the bubble and the thickness of the other is thinner than the standard thickness of the bubble.

In this case, the determining unit 52 first compares the sum of the thicknesses of the two overlapping portions, that is, the thickness of the flat film corresponding to the two portions with the reference thickness of the flat film.

If both are equal, the determination unit 52 determines that the lip width adjustment amount corresponding to the two portions is zero. If the two portions are not equal, the determination unit 52 adjusts only the lip width corresponding to the one of the two overlapping portions that has a larger absolute difference from the reference thickness of the bubble, and makes the sum of the thicknesses the reference thickness of the flat film. equal to For example, the determining unit 52 determines zero as the adjustment amount of the lip width corresponding to the smaller absolute difference from the reference thickness of the valve. Further, the determination unit 52 determines that the thickness of the bubble having a larger absolute difference from the reference bubble thickness is, for example, the bubble reference thickness + 0.2 mm, and the bubble thickness having the larger absolute difference is the bubble thickness. If the reference thickness is −0.3 mm, then the amount of adjustment of the corresponding lip width is determined so that the thickness with the larger absolute difference becomes the reference thickness of the bubble −0.2 mm.

Note that the determination unit 52 compares the absolute differences between the two portions with respect to the bubble reference thickness, and then adjusts only the lip width corresponding to the one with the smaller absolute difference from the bubble reference thickness, and adds The thickness obtained may be equal to the reference thickness of the flat film. In this case, the determination unit 52 determines zero as the adjustment amount of the lip width corresponding to the larger absolute difference from the reference thickness of the valve. Further, the determination unit 52 determines that the thickness of the bubble having a smaller absolute difference from the reference bubble thickness is, for example, the bubble reference thickness + 0.2 mm, and the bubble thickness having a larger absolute difference is the bubble thickness. If the reference thickness is −0.3 mm, the corresponding adjustment amount of the lip width may be determined so that the thickness with the smaller absolute difference becomes the bubble reference thickness +0.3 mm.

The motion control section 60 controls the motion of the inflation molding device 1 . The operation control section 60 particularly controls the lip width according to the adjustment amount determined by the determination section 52 .

The above is the configuration of the inflation molding apparatus 1 . Next, the operation will be explained. This process is repeatedly executed at a predetermined cycle.

The thickness measuring unit 6 measures the thickness at each position in the circumferential direction of the bubble during molding, and transmits the measured thickness to the control device 7 .

Based on the thickness of the bubble at each position in the circumferential direction, the controller 7 determines the adjustment amount of the lip width at each position in the circumferential direction so that the thickness of the flat film is uniform in the width direction. The controller 7 then adjusts the lip width at each position in the circumferential direction according to the determination.

Next, the effects of this embodiment will be described. According to this embodiment, when both of the two portions that overlap when folded are thicker than the standard thickness of the bubble, or both are thinner than the standard thickness, one of the two portions corresponds to the Only the lip width is adjusted and the corresponding lip width is not adjusted. As a result, the amount of adjustment (position to be adjusted) can be relatively small. Also, preferably, only the lip width corresponding to the larger difference from the reference bubble thickness of the two portions is adjusted. In this case, the thickness of the two portions can be brought closer to the reference thickness of the bubble than otherwise.

Further, according to the present embodiment, when the thickness of one of the two portions that overlap when folded is thicker than the standard thickness of the bubble and the thickness of the other is thinner than the standard thickness of the bubble, the thickness of the two portions is equal to the reference thickness of the flat film, the lip width corresponding to the two portions is not adjusted. As a result, the amount of adjustment (position to be adjusted) can be relatively small.

If the sum of the thicknesses of the two portions is not equal to the reference thickness of the flat film, only the lip width corresponding to one of the two portions is adjusted and the lip width corresponding to the other is not adjusted. As a result, the amount of adjustment (position to be adjusted) can be relatively small. Also, preferably, only the lip width corresponding to the larger absolute difference from the reference bubble thickness of the two portions is adjusted. In this case, the thickness of the two portions can be brought closer to the reference thickness of the bubble than otherwise.

One aspect of the present invention has been described above based on the first embodiment. Next, a modification related to the first embodiment will be described.

A first modification of the first embodiment will be described.
In the embodiment and the modified example described above, the case where the lip width is adjusted for both the case where the bubble thickness is thicker than the reference thickness and the case where the bubble thickness is thinner than the reference thickness has been described. The lip width may be adjusted, or may be adjusted only when the film is thicker than the reference film thickness. According to this modified example, the adjustment amount (adjustment location) can be reduced.

A second modification of the first embodiment will be described.
In the embodiment and the modified example described above, the case where the lip width is controlled so that the thickness of the flat film approaches the reference thickness has been described. may be controlled to have a thickness that is reversed.

(1) When the thickness of the two portions that overlap when the bubble is folded is equal to the reference thickness of the bubble Determine the adjustment amount as zero.

(2) When the thicknesses of the two portions that overlap when the bubble is folded are both thicker than the standard thickness of the bubble, or both are thinner than the standard thickness of the bubble. The lip widths corresponding to both of the portions are adjusted to determine the sum of the thicknesses of the two portions to be the inverse of the current flat film thickness with respect to the reference thickness of the flat film. . For example, if the thickness of one of the two portions is the reference thickness of the bubble + 0.2 mm and the thickness of the other is the reference thickness of the bubble + 0.3 mm, that is, the total thickness is ( 2×reference thickness+0.5 mm), the total thickness is (2×reference thickness−0.5 mm), that is, the thickness of the flat film after reversal is the current thickness of the flat film−1. Determine the adjustment amount of the lip width corresponding to the two overlapping portions so that the width is 0 mm.

In this case, the determining unit 52 may, for example, determine the adjustment amount of the lip width corresponding to the two portions so that the amount of change in the thickness of the two portions is equal. Specifically, the determining unit 52 sets the thickness variation of the two portions to 0.5 mm, that is, the thickness of one of the portions is the reference thickness of the bubble −0.3 mm, and the thickness of the other is the thickness of the bubble. A corresponding lip width adjustment amount may be determined so that the reference thickness is −0.2 mm.

Further, for example, the determination unit 52 compares the differences between the two portions with respect to the bubble reference thickness, and determines that the adjustment amount of the lip width corresponding to the one with the smaller difference from the bubble reference thickness is smaller (in other words, the thickness Each adjustment amount may be determined so that the amount of adjustment of the lip width corresponding to the larger difference from the reference thickness of the bubble is larger (in other words, the amount of change in thickness is larger). Specifically, for example, the determining unit 52 determines that the one thickness having a smaller difference from the reference bubble thickness is the reference bubble thickness −0.1 mm (the amount of change in thickness is 0.3 mm), and the difference from the reference bubble thickness is The corresponding adjustment amount of the lip width may be determined so that the thickness of the other layer with the larger difference is equal to the reference thickness of the bubble minus 0.4 mm (the amount of change in thickness is 0.7 mm). For example, the determining unit 52 determines that one thickness is the reference thickness of the bubble −0.25 mm (the amount of change in thickness is 0.45 mm), and the other thickness is also the reference thickness of the bubble −0.25 mm (the amount of change in thickness is 0.45 mm). 0.55 mm), i.e., the difference from the reference thickness is equal for the two portions, the corresponding adjustment of the lip width may be determined. Further, for example, the determination unit 52 sets the one thickness to the bubble reference thickness +0.2 mm (the amount of change in thickness is 0 mm), and sets the other thickness to the reference bubble thickness -0.7 mm (the amount of change in thickness is 1.0 mm). In other words, only the lip width corresponding to the larger difference from the reference thickness of the bubble may be adjusted.

Further, for example, the determination unit 52 compares the differences between the two portions with respect to the bubble reference thickness, and determines that the adjustment amount of the lip width corresponding to the one with the smaller difference from the bubble reference thickness is larger (in other words, the thickness Each adjustment amount may be determined such that the adjustment amount of the lip width corresponding to the larger difference from the reference bubble thickness is smaller (in other words, the thickness variation is smaller). Specifically, for example, the determining unit 52 determines that the one thickness having a smaller difference from the reference bubble thickness is the reference bubble thickness −0.4 mm (the amount of change in thickness is 0.6 mm), and the difference from the reference bubble thickness is The corresponding adjustment amount of the lip width may be determined so that the thickness of the other layer with the larger difference is equal to the reference thickness of the bubble minus 0.1 mm (the amount of change in thickness is 0.4 mm). Further, for example, the determination unit 52 determines that one thickness is the reference thickness of the bubble −0.8 mm (the amount of change in thickness is 1.0 mm), and the other thickness remains the reference thickness of the bubble +0.3 mm (change in thickness A corresponding amount of lip width adjustment may be determined such that the amount is 0 mm). In other words, only the lip width corresponding to the smaller difference from the reference thickness of the bubble may be adjusted.

(3) When the thickness of one of the two parts that overlap when the bubble is folded is thicker than the standard thickness of the bubble and the thickness of the other is thinner than the standard thickness of the bubble.

In this case, the determining unit 52 first compares the sum of the thicknesses of the two overlapping portions, that is, the thickness of the flat film corresponding to the two portions with the reference thickness of the flat film.

If both are equal, the determination unit 52 determines that the lip width adjustment amount corresponding to the two portions is zero. If the two are not equal, the determination unit 52 adjusts the lip width corresponding to at least one of the two overlapping portions to make the thickness of the sum of the thicknesses of the two portions different from the reference thickness of the flat film. is determined to be the inverse thickness of the current flat film thickness. For example, the determining unit 52 determines that the thickness of one of the two portions is the reference thickness of the bubble +0.2 mm and the thickness of the other is the reference thickness of the bubble -0.3 mm. If (2×reference thickness−0.1 mm), the total thickness is (2×reference thickness+0.1 mm), that is, the thickness of the flat film after reversal is the current thickness of the flat film+0.1 mm. Determine the amount of lip width adjustment corresponding to the two overlapping portions so that it is 2 mm.

In this case, the determining unit 52 may, for example, determine the adjustment amount of the lip width corresponding to the two portions so that the amount of change in the thickness of the two portions is equal. Specifically, the determination unit 52 sets the thickness variation of the two portions to 0.1 mm, that is, the thickness of one of the portions is the reference thickness of the bubble + 0.3 mm, and the thickness of the other is the reference thickness of the bubble. A corresponding lip width adjustment may be determined for a thickness of -0.2 mm.

Further, for example, the determination unit 52 compares the differences between the two portions with respect to the bubble reference thickness, and determines that the adjustment amount of the lip width corresponding to the one with the smaller difference from the bubble reference thickness is smaller (in other words, the thickness Each adjustment amount may be determined so that the amount of adjustment of the lip width corresponding to the larger difference from the reference thickness of the bubble is larger (in other words, the amount of change in thickness is larger). Specifically, for example, the determining unit 52 determines that the one thickness having a smaller difference from the reference bubble thickness is the reference bubble thickness +0.25 mm (the amount of change in thickness is 0.05 mm), and the difference from the reference bubble thickness is The corresponding adjustment amount of the lip width may be determined so that the thickness of the other layer having the larger value is the reference thickness of the bubble minus 0.15 mm (the amount of change in thickness is 0.15 mm). Further, for example, the determining unit 52 determines that one thickness is the bubble reference thickness +0.05 mm (thickness variation is 0.15 mm), and the other thickness is the bubble reference thickness +0.05 mm (thickness variation is 0.05 mm). .35 mm), i.e., the difference from the reference thickness is equal for the two portions, the corresponding adjustment of the lip width may be determined.

Further, for example, the determination unit 52 compares the differences between the two portions with respect to the bubble reference thickness, and determines that the adjustment amount of the lip width corresponding to the one with the smaller difference from the bubble reference thickness is larger (in other words, the thickness Each adjustment amount may be determined such that the adjustment amount of the lip width corresponding to the larger difference from the reference bubble thickness is smaller (in other words, the thickness variation is smaller). Specifically, for example, the determining unit 52 determines that the one thickness having a smaller difference from the reference bubble thickness is the reference bubble thickness +0.35 mm (the amount of change in thickness is 0.15 mm), and the difference from the reference bubble thickness is The corresponding adjustment amount of the lip width may be determined so that the thickness of the other lip with the larger value is the reference thickness of the bubble minus 0.25 mm (the amount of change in thickness is 0.05 mm). Further, for example, the determination unit 52 sets the one thickness to the bubble reference thickness +0.4 mm (the amount of change in thickness is 0.2 mm), and sets the other thickness to the bubble reference thickness -0.3 mm (the thickness change amount is 0.3 mm). A corresponding amount of lip width adjustment may be determined such that the amount is 0 mm). In other words, only the lip width corresponding to the smaller difference from the reference thickness of the bubble may be adjusted.

According to this modification, a flat film thicker than the reference thickness and a flat film thinner than the reference thickness are alternately wound and averaged at a certain position in the width direction of the flat film. becomes uniform in the width direction. That is, the bumps and dents of the film roll body 11 can be reduced or made smaller.

A third modification of the first embodiment will be described.
In the embodiment and the modified example described above, the thickness of the flat film at each position in the width direction is estimated based on the thickness at each position in the circumferential direction of the bubble measured by the thickness measuring unit 6, and the estimated thickness of the flat film is obtained. As for the position where is the reference thickness, the case where the corresponding lip width is not adjusted has been described, but the present invention is not limited to this. FIG. 4 is a diagram showing a schematic configuration of an inflation molding apparatus 1 according to a modification. In this modification, the inflation molding apparatus 1 further includes another thickness measuring section 22 between the take-up machine 5 and the winder 20 for measuring the thickness of each position in the width direction of the flat film. The thickness measurement unit 22 transmits the measured thickness data to the control device 7 . The determining unit 52 compares the thickness of each position in the width direction of the flat film measured by the thickness measuring unit 22 with the reference thickness of the flat film (twice the reference thickness of the bubble). With respect to each position in the width direction of the flat film, the determining unit 52 determines that the adjustment amount of the corresponding two lip widths is zero for positions where the thickness is equal to the reference thickness of the flat film, and for other positions, particularly For example, without limitation, it may be determined to adjust only one lip width of the two corresponding lip widths, or it may be determined to adjust both lip widths so that the amount of change in thickness is equal. Alternatively, it may be determined to adjust both lip widths so that the absolute differences from the bubble reference thickness are equal. According to this modification, the same effects as those of the embodiment can be obtained.

(Second embodiment)
2nd Embodiment is demonstrated centering around difference with 1st Embodiment.

In the present embodiment, the determination unit 52 determines the adjustment amount of the lip width at each position based on the thickness of each position in the circumferential direction of the bubble, that is, regardless of the thickness of the overlapping portion when folded. Determines the amount of position lip width adjustment.

Specifically, the determining unit 52 determines the amount of adjustment of the corresponding lip width so that the portion of the bubble thicker than the reference thickness becomes the reference thickness, and the lip width corresponding to the portion of the bubble equal to or thinner than the reference thickness. Determine the width adjustment amount as zero.

As a modified example, the determining unit 52, on the contrary, determines the amount of adjustment of the corresponding lip width so that the portion of the bubble thinner than the reference thickness becomes the reference thickness, and the portion of the bubble thicker than or equal to the reference thickness is determined. may be determined to be zero.

According to this embodiment, it is possible to reduce the amount of adjustment (position to be adjusted).

One aspect of the present invention has been described above based on the second embodiment.

Next, a modification common to the first and second embodiments will be described.

In the first and second embodiments, the lip width is adjusted to adjust the thickness of the bubble at each position in the circumferential direction, and thus the thickness at each position in the width direction of the flat film. , and may be achieved by adjusting at least one other adjustment element instead of, or in addition to, the lip width. In this case, the determination unit 52 also determines the adjustment amounts of the other adjustment elements. Other adjustment factors include, for example, the air volume and air temperature of the cooling air.

In addition, in the first and second embodiments, the lip width adjustment margin may be used up while the lip width is being adjusted. In particular, if the lip width is adjusted only when the bubble is thicker than the reference thickness or thinner than the reference thickness, as in the first modification of the first embodiment and the second embodiment, , such a situation is likely to occur. When the adjustment allowance is used up, no further adjustment is possible.

Therefore, when the adjustment allowance is used up, or when the remaining adjustment allowance at any position in the circumferential direction becomes equal to or less than a predetermined value, the control device 7 adjusts the adjustment allowance at all positions in the circumferential direction, for example, When the allowance is used up or the remaining adjustment allowance reaches a predetermined value, the adjustment margin may be secured by, for example, returning to the state at the start of molding, or a predetermined amount may be secured. In this case, the influence of securing the adjustment margin is absorbed by adjusting other adjustment elements, such as the air volume and air temperature of the cooling air, or both, so that the thickness of the bubble does not fall outside the allowable range. good too. The amount of adjustment of other adjustment elements for absorbing the influence of securing the adjustment margin may be determined in advance based on experiments or the like.

The control device 7 may store the position in the circumferential direction at which the adjustment margin is secured and the secured amount. The control device 7 may also store the circumferential positions and adjustment amounts of other corresponding adjustment elements adjusted to ensure the adjustment allowance. The control device 7 displays the stored amount of adjustment allowance for each position in the circumferential direction, and the circumferential positions and adjustment amounts of other adjustment elements adjusted to secure the adjustment allowance, on a screen on which setting conditions are displayed. may be displayed in

Further, when the lip width adjustment margin is used up, the control device 7 may change the adjustment element for adjusting the film thickness from the lip width to another adjustment element thereafter. For example, when the lip width adjustment margin is used up, the control device 7 may thereafter adjust the film thickness by adjusting the cooling air volume, air temperature, or both. The control device 7 may display on the screen which adjustment element is currently adjusting each position in the circumferential direction. Specifically, for example, the control device 7 determines that for each position in the circumferential direction, one position is adjusted by the lip width, another position is adjusted by the cooling air, and another position is adjusted by both the lip width and the cooling air. You may display on a screen the information that it is adjusted by .

The configuration and operation of the inflation molding apparatus according to the embodiment have been described above. Those skilled in the art will understand that these embodiments are merely examples, and that various modifications can be made to the combination of each component, and that such modifications are within the scope of the present invention.

1 inflation molding device, 2 die, 6 thickness measuring section, 7 control device, 52 determining section.

Claims (4)

An inflation molding device that forms a tubular film, folds it into a flat film, and winds up the flat film to form a roll body,
a controller for determining the amount of adjustment of the adjustment element for adjusting the thickness of the tubular film based on the information about the thickness of the flat film ;
When the thickness at a certain position in the width direction of the flat film indicated by the information is different from the reference thickness of the flat film, the control device determines the reference thickness of the tubular film for two corresponding portions of the tubular film. A inflation molding apparatus, characterized in that the differences in thickness are compared with each other and the adjustment elements are adjusted such that the amount of adjustment for the larger difference is greater than the amount of adjustment for the smaller difference. 2. The inflation molding apparatus according to claim 1, wherein the control device determines the amount of adjustment of the adjustment element based on a result of comparison between the thickness indicated by the information and a reference thickness of the flat film. When the thickness at a certain position in the width direction of the flat film indicated by the information is equal to the reference thickness of the flat film, the control device does not adjust the adjusting elements for the corresponding two portions of the tubular film. The inflation molding apparatus according to claim 1 or 2, characterized by: 4. The inflation molding apparatus according to any one of claims 1 to 3 , wherein the thicknesses indicated by the information are measured values of thicknesses of two corresponding portions of the tubular film.

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