JP2017177691A - Inspection method, film production method, inspection instrument, film production apparatus, and inspection program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection method capable of early detecting a periodical thickness unevenness of a film, a film production method, an inspection instrument, a film production apparatus, and an inspection program.SOLUTION: An inspection method regarding one embodiment of the present invention includes: a first data transformation step S13 of computing a first frequency spectrum H(f) by subjecting data h(t) of a thickness distribution in a flowing direction of a film to Fourier transformation; an alarm step S32 of alarming when there is a peak in the first frequency spectrum H(f); a second data transformation step S23 of computing a plurality of second frequency spectra R(f) corresponding to respective rolls by subjecting data r(t) of rotation amounts of a plurality of the rolls conveying the film to Fourier transformation; and an information-submitting step S34 of indicating a roll corresponding to a second frequency spectrum R(f) in which a frequency generating a peak equates to the first frequency spectrum H(f).SELECTED DRAWING: Figure 4

Description

  The present invention relates to an inspection method, a film manufacturing method, an inspection apparatus, a film manufacturing apparatus, and an inspection program.

  Unevenness in the thickness of the film adversely affects the physical properties, processability and winding shape of the film. Therefore, it is important to form the film uniformly. For example, Patent Documents 1 and 2 describe a film with reduced film thickness unevenness and manufacturing conditions thereof.

JP-A-8-281794 JP 2000-103177 A

  If a machine trouble occurs during film formation, the film thickness may periodically fluctuate in the film flow direction. Periodic thickness unevenness of the film adversely affects the physical properties, processability and winding shape of the film. Therefore, it is necessary to detect such thickness unevenness at an early stage and to promptly respond to machine troubles.

  An object of the present invention is to provide an inspection method, a film manufacturing method, an inspection apparatus, a film manufacturing apparatus, and an inspection program that can detect the periodic thickness unevenness of the film at an early stage.

  An inspection method according to an aspect of the present invention includes a first data conversion step of calculating a first frequency spectrum by performing Fourier transform on thickness distribution data in the film flow direction, and a peak in the first frequency spectrum. An alarm step for issuing an alarm when present, and a Fourier transform of rotation amount data of a plurality of rolls conveying the film, respectively, and calculating a plurality of second frequency spectra corresponding to the respective rolls A data conversion step, and an information presentation step for presenting information indicating the roll corresponding to the second frequency spectrum in which a frequency at which a peak occurs coincides with the first frequency spectrum.

  According to this configuration, periodic thickness unevenness of the film can be detected at an early stage, and prompt response to machine troubles can be promoted. In addition, it is possible to easily identify the roll that causes the uneven thickness of the film.

  In the inspection method according to an aspect of the present invention, for example, the plurality of rolls include a cast roll to which a resin that is a raw material of the film adheres, a nip roll that sandwiches the resin between the cast rolls, The take-off roll that receives the resin attached to the cast roll and at least one roll are included.

  According to the inventor's investigation, the periodic thickness unevenness of the film is mainly caused by fluctuations in the rotation amount of the cast roll, nip roll, or take-off roll. Therefore, by monitoring the rotation amount of these rolls, it is possible to quickly cope with machine troubles.

  In the inspection method according to an aspect of the present invention, for example, in the first data conversion step, the thickness distribution data of the film on the downstream side of the take-off roll is Fourier-transformed.

  By monitoring the thickness distribution of the film that has passed through the cast roll, nip roll, and take-off roll, it is possible to monitor fluctuations in the rotation amount of these rolls that are likely to cause periodic thickness unevenness of the film.

  In the inspection method according to an aspect of the present invention, for example, in the first data conversion step, the thickness distribution data in a plurality of inspection lines parallel to the flow direction is Fourier-transformed to each inspection line. A plurality of corresponding first frequency spectra are calculated, and in the alarm step, an alarm is issued when a peak exists in at least one of the first frequency spectra.

  According to this configuration, even if it is difficult to detect the peak of the first frequency spectrum in a specific inspection line, it is possible to reliably detect periodic thickness unevenness of the film.

  The film manufacturing method according to an aspect of the present invention includes a forming step of transferring a film while forming the film, and calculating a first frequency spectrum by performing Fourier transform on data of a thickness distribution in the flow direction of the film being transferred. One data conversion step, an alarm step for issuing an alarm when a peak exists in the first frequency spectrum, and a Fourier transform for each of the rotation amount data of a plurality of rolls transporting the film, A second data conversion step for calculating a plurality of second frequency spectra corresponding to the information, and information indicating the roll corresponding to the second frequency spectrum in which the frequency at which the peak occurs coincides with the first frequency spectrum An information presenting step to present.

  According to this configuration, periodic thickness unevenness of the film can be detected at an early stage, and prompt response to machine troubles can be promoted. In addition, it is possible to easily identify the roll that causes the uneven thickness of the film.

  An inspection apparatus according to an aspect of the present invention includes a first data conversion unit that calculates a first frequency spectrum by Fourier-transforming data on a thickness distribution in the film flow direction, and a peak in the first frequency spectrum. An alarm unit that issues an alarm when present, and a Fourier transform of each of rotation amount data of a plurality of rolls conveying the film, and a second frequency spectrum corresponding to each of the rolls is calculated. A data conversion unit; and an information presentation unit that presents information indicating the roll corresponding to the second frequency spectrum in which a frequency at which a peak occurs matches the first frequency spectrum.

  According to this configuration, periodic thickness unevenness of the film can be detected at an early stage, and prompt response to machine troubles can be promoted. In addition, it is possible to easily identify the roll that causes the uneven thickness of the film.

  A film manufacturing apparatus according to an aspect of the present invention calculates a first frequency spectrum by Fourier-transforming a forming unit that conveys a film while forming the film, and data on a thickness distribution in the flow direction of the film being conveyed. One data conversion unit, an alarm unit that issues an alarm when a peak is present in the first frequency spectrum, and a Fourier transform of each rotation amount data of a plurality of rolls carrying the film, and each of the rolls A second data converter that calculates a plurality of second frequency spectra corresponding to the information, and information indicating the roll corresponding to the second frequency spectrum in which the frequency at which the peak occurs coincides with the first frequency spectrum And an information presentation unit to present.

  According to this configuration, periodic thickness unevenness of the film can be detected at an early stage, and prompt response to machine troubles can be promoted. In addition, it is possible to easily identify the roll that causes the uneven thickness of the film.

  An inspection program according to an aspect of the present invention includes a first data conversion step of calculating a first frequency spectrum by Fourier-transforming data on a thickness distribution in the film flow direction, and a peak in the first frequency spectrum. An alarm step for issuing an alarm when present, and a Fourier transform of rotation amount data of a plurality of rolls conveying the film, respectively, and calculating a plurality of second frequency spectra corresponding to the respective rolls The computer executes a data conversion step and an information presentation step for presenting information indicating the roll corresponding to the second frequency spectrum in which the frequency at which the peak occurs matches the first frequency spectrum.

  According to this configuration, periodic thickness unevenness of the film can be detected at an early stage, and prompt response to machine troubles can be promoted. In addition, it is possible to easily identify the roll that causes the uneven thickness of the film.

  According to the present invention, it is possible to provide an inspection method, a film manufacturing method, an inspection apparatus, a film manufacturing apparatus, and an inspection program that can detect the periodic thickness unevenness of the film at an early stage.

FIG. 1 is a schematic view of a film manufacturing apparatus according to the first embodiment. FIG. 2 is a diagram showing the arrangement of the first sensor. FIG. 3 is a flowchart for explaining the film manufacturing method. FIG. 4 is a flowchart for explaining the inspection method in detail. FIG. 5 is a diagram illustrating a first frequency spectrum of a film thickness distribution when a malfunction occurs in the cast roll. FIG. 6 is a diagram illustrating a second frequency spectrum of the rotation amount of the cast roll when a malfunction occurs in the cast roll. FIG. 7 is a diagram showing a first frequency spectrum of the film thickness distribution when no periodic thickness unevenness occurs in the film. FIG. 8 is a diagram showing a second frequency spectrum of the rotation amount of the cast roll when no periodic thickness unevenness occurs in the film. FIG. 9 is a diagram showing a second frequency spectrum of the rotation amount of the nip roll when no periodic thickness unevenness occurs in the film. FIG. 10 is a diagram illustrating a second frequency spectrum of the rotation amount of the take-off roll when no periodic thickness unevenness occurs in the film. FIG. 11 is a view of the thickness measuring unit according to the second embodiment as viewed from above the film conveyance path.

[First embodiment]
FIG. 1 is a schematic view of a film manufacturing apparatus 1 according to the first embodiment. The film manufacturing apparatus 1 includes, for example, a forming unit 200 and an inspection unit 100.

  The forming unit 200 conveys the film 250 while forming it. The forming unit 200 includes, for example, a T die 210 and a plurality of rolls 290.

  The T die 210 pushes out a resin 250a that is a raw material of the film 250 from a linear discharge port. The resin 250a is conveyed while being cooled by a plurality of rolls 290. The resin 250 a becomes a thin long film 250 while being conveyed by the plurality of rolls 290. The film 250 conveyed by the plurality of rolls 290 is wound into a roll and shipped.

  The plurality of rolls 290 include, for example, a cast roll 220, a nip roll 230, and a take-off roll 240. The cast roll 220 is installed immediately below the T die 210, and the resin 250a pushed out from the T die 210 adheres thereto. The nip roll 230 sandwiches the resin 250 a between the cast roll 220. The take-off roll 240 receives the resin 250 a attached to the cast roll 220 and supplies it to the downstream roll 290.

  The inspection unit 100 is an inspection device that inspects the thickness unevenness of the film 250. The inspection unit 100 includes, for example, a thickness measurement unit 10, a processing unit 20, a plurality of sensors 30, an alarm unit 41, and an information presentation unit 42.

  The thickness measuring unit 10 measures the thickness of the film 250. For example, the thickness measuring unit 10 is installed above the conveyance path of the film 250. The thickness measuring unit 10 measures the thickness of the film 250 flowing in one direction at regular intervals. The thickness measuring unit 10 supplies the measured value hD of the thickness of the film 250 to the processing unit 20. Thereby, the thickness distribution of the flow direction FR of the film 250 is measured. The flow direction FR means the transport direction of the film 250 transported by a plurality of rolls 290. The flow direction FR coincides with the longitudinal direction of the film 250. The thickness measuring unit 10 measures, for example, the thickness of the film 250 at the center in the film width direction orthogonal to the flow direction FR.

  The plurality of sensors 30 monitor the operation of the molding unit 200. In the present embodiment, for example, a first sensor 31, a second sensor 32, and a third sensor 33 are provided as the plurality of sensors 30. The first sensor 31 detects the amount of rotation of the rotary shaft 221 of the cast roll 220. The second sensor 32 detects the amount of rotation of the rotating shaft 231 of the nip roll 230. The third sensor 33 detects the amount of rotation of the rotation shaft 241 of the take-off roll 240.

  FIG. 2 is a diagram showing the arrangement of the first sensors 31. The first sensor 31 is, for example, a rotary encoder attached to the rotation shaft 221 of the cast roll 220. The first sensor 31 rotates integrally with the rotation shaft 221 and detects the rotation amount of the outer peripheral surface of the rotation shaft 221. Although not shown, the second sensor 32 and the third sensor 33 have the same configuration as the first sensor 31. The plurality of sensors 30 detect the rotation amount of the outer peripheral surface of the rotation shaft of the corresponding roll 290 and supply the measured value rD of the rotation amount to the processing unit 20.

  Hereinafter, when distinguishing a plurality of rolls 290, a number is added to the end of the code of each roll 290. For example, the roll number of the cast roll 220 corresponding to the first sensor 31 is the first. The roll number of the nip roll 230 corresponding to the second sensor 32 is second. The roll number of the take-off roll 240 corresponding to the third sensor 33 is third. The same applies to the case where the measured value rD corresponding to each roll 290 is distinguished. The same applies to the case where the machining data of the actual measurement value rD corresponding to each roll 290 is distinguished.

  The processing unit 20 includes a first data acquisition unit 21, a second data acquisition unit 22, a first data conversion unit 23, a second data conversion unit 24, an analysis unit 25, and an output unit 26. And a program storage unit 29.

  The first data acquisition unit 21 acquires an actual measurement value hD of the thickness of the film 250 measured by the thickness measurement unit 10. The first data acquisition unit 21 creates time-series data of the thickness of the film 250 by associating the actual measurement value hD with the measurement time t. The first data acquisition unit 21 supplies this time-series data to the first data conversion unit 23 as data h (t) of the thickness distribution in the flow direction FR of the film 250 being conveyed in the forming unit 200.

  The first data converter 23 performs Fourier transform on the thickness distribution data h (t) in the flow direction FR of the film 250 to calculate the first frequency spectrum H (f). f is the frequency. H (f) represents the ratio of the vibration component of the frequency f included in the data h (t). The first data conversion unit 23 supplies the first frequency spectrum H (f) to the analysis unit 25.

The second data acquisition unit 22 acquires an actual measurement value rD of the rotation amount of each roll 290. The second data acquisition unit 22 creates time-series data regarding the rotation amount of each roll 290 by associating the actual measurement value rD of the rotation amount of each roll 290 with the measurement time t. The second data acquisition unit 22 associates these time series data with the roll number of each roll 290. The second data acquisition unit 22 supplies a plurality of time-series data associated with the roll number to the second data conversion unit 24 as rotation amount data r (t) of the plurality of rolls 290. For example, assuming that the rotation amount data of the i-th roll (i is an integer from 1 to 3) 290 _i is r _i (t), the second data acquisition unit 22 has three rolls from the first to the third. 290 rotation amount data r ₁ (t) to r ₃ (t) are supplied to the second data conversion unit 24.

The second data conversion unit 24 performs Fourier transform on the rotation amount data r (t) of the plurality of rolls 290 that transport the film 250, and a plurality of second frequency spectra R (f) corresponding to the respective rolls 290. ) Is calculated. f is the frequency. R (f) indicates the ratio of the vibration component of the frequency f included in r (t). For example, assuming that the second frequency spectrum corresponding to the i-th roll 290 _i is R _i (f), the second data conversion unit 24 includes the three frequency bands corresponding to the three rolls 290 from the first to the third. The second frequency spectra R ₁ (f) to R ₃ (f) are respectively supplied to the analysis unit 25.

  The analysis unit 25 detects the peak frequency fH of the first frequency spectrum H (f). The analysis unit 25 supplies the frequency fH to the output unit 26 as first frequency information. The analysis unit 25 determines that a peak equal to or higher than the first threshold is a peak of the first frequency spectrum H (f). The first threshold is 0.04%, for example. When no peak exists in the first frequency spectrum H (f), the analysis unit 25 sets, for example, a specific numerical value (for example, 0) as the frequency fH.

The analysis unit 25 detects the peak frequency fR for each of the plurality of second frequency spectra R (f) corresponding to each roll 290. The analysis unit 25 supplies the frequency fR corresponding to each roll 290 to the output unit 26 as second frequency information. For example, if the peak frequency corresponding to the i-th roll 290 _i is fR _i , the analysis unit 25 outputs the three frequencies fR _{1 to} fR ₂ corresponding to the first to third rolls 290 as the output unit. 26. The analysis unit 25 determines that the peak equal to or higher than the second threshold is the peak of the second frequency spectrum R (f). The second threshold is, for example, 0.4%. When no peak exists in the second frequency spectrum R (f), the analysis unit 25 supplies a specific numerical value or symbol to the output unit 26 as second frequency information.

  The output unit 26 determines whether or not a peak exists in the first frequency spectrum H (f) based on the first frequency information. The output unit 26 supplies information regarding whether or not a peak exists in the first frequency spectrum H (f) to the alarm unit 41 as the first output information IO1.

  Based on a plurality of pieces of second frequency information corresponding to each roll 290, the output unit 26 generates a second frequency spectrum R (f) (hereinafter referred to as the first frequency spectrum H (f) at which the frequency at which the peak occurs corresponds. , Described as a specific second frequency spectrum R (f)). The output unit 26 supplies the roll number of the roll 290 corresponding to the specific second frequency spectrum R (f) to the information presentation unit 42 as the second output information IO2.

  Whether the frequency fR and the frequency fH coincide with each other is determined by comprehensively considering the measurement error of the thickness measurement unit 10, the measurement error of the sensor 30, the calculation error of the processing unit 20, and the like. For example, if the difference between the frequency fR and the frequency fH is 5% or less of the frequency fH, the output unit 26 determines that the frequency fR and the frequency fH match.

  Based on the first output information IO1, the alarm unit 41 issues an alarm notifying that a periodic thickness unevenness has occurred in the film 250 during the formation of the film 250. For example, the alarm unit 41 issues an alarm when a peak exists in the first frequency spectrum H (f). The alarm may be anything that can alert the user. The alarm means is not particularly limited. For example, the alarm unit 41 may be a siren device that alerts the user with sound and light, or may be a display device that displays characters and images that alert the user.

  Based on the second output information IO2, the information presentation unit 42 presents information on a specific roll 290 that causes periodic thickness unevenness of the film 250 to the user during the formation of the film 250. For example, the information presentation unit 42 corresponds to a specific second frequency spectrum R (f) (a second frequency spectrum R (f) in which the frequency at which the peak occurs matches the first frequency spectrum H (f)). Information indicating the role 290 is presented. The means for presenting information is not particularly limited. For example, the information presentation unit 42 may be a siren device installed in the vicinity of each roll 290, or may be a display device that displays characters and images that inform the user of the position and type of the roll 290.

  The program storage unit 29 stores an inspection program and data for the processing unit 20 to perform various processes. The inspection program is a program that causes a computer to execute the inspection method according to the present embodiment. The processing unit 20 performs various processes according to the inspection program stored in the program storage unit 29. The processing unit 20 is, for example, a computer that includes a processor and a memory. The memory includes a RAM (Random Access Memory) and a ROM (Read Only Memory). The processing unit 20 executes the inspection program to thereby execute a first data acquisition unit 21, a second data acquisition unit 22, a first data conversion unit 23, a second data conversion unit 24, an analysis unit 25, and an output. It functions as the unit 26.

  FIG. 3 is a flowchart for explaining the film manufacturing method of this embodiment.

  First, the forming unit 200 conveys the film 250 while forming it (forming step S1). The resin 250a extruded from the T die 210 is caused to flow downstream while the thickness is made uniform by a plurality of rolls 290 including a cast roll 220, a nip roll 230, and a take-off roll 240. As a result, the long film 250 is continuously formed.

  Next, the inspection unit 100 sequentially measures the thickness of the film 250 flowing on the conveyance path, and inspects whether or not periodic thickness unevenness occurs in the film 250 being conveyed (inspection step S2).

  Next, when it is determined that periodic thickness unevenness occurs in the film 250 being conveyed (inspection step S2: Yes), the alarm unit 41 issues an alarm and alerts the operator (alarm) Step S3). For example, it is determined that periodic unevenness occurs when a peak equal to or higher than the first threshold exists in the first frequency spectrum H (f).

  The worker continues to operate the molding unit 200 for a while after the warning is issued. The operator observes whether or not there is no peak in the first frequency spectrum H (f) that is greater than or equal to the third threshold greater than the first threshold (follow-up step S4). The third threshold is, for example, 0.06%.

  During the follow-up observation, when a peak equal to or greater than the third threshold is present in the first frequency spectrum H (f) (follow-up observation step S4: Yes), the operator stops the operation of the forming unit 200, The forming of the film 250 is interrupted. Then, the worker performs maintenance of the film manufacturing apparatus 1 (maintenance step S5). When periodic thickness unevenness does not occur in the film 250 being conveyed (inspection step S2: No), and during the follow-up observation, a peak equal to or higher than the third threshold is present in the first frequency spectrum H (f). When not (follow-up observation step S4: No), the formation of the film 250 is continued.

  FIG. 4 is a flowchart for explaining in detail the inspection method used in the inspection step S2 and the alarm step S3.

  The inspection method of the present embodiment includes, for example, a first analysis step S10, a second analysis step S20, and a third analysis step S30. The first analysis step S10 is a step of performing frequency analysis on time-series data indicating the thickness distribution of the film 250 in the flow direction FR. The second analysis step S <b> 20 is a step of performing frequency analysis on time-series data indicating a temporal change in the rotation amount of the roll 290 that conveys the film 250. The third analysis step S30 detects a change in the film 250 being formed on the basis of the analysis result of the first analysis step S10 and the analysis result of the second analysis step S20, and forms the cause of the change. This is a step of detecting an abnormal part of the unit 200. Either the first analysis step S10 or the second analysis step S20 may be performed first.

  In the first analysis step S10, first, the thickness measuring unit 10 installed above the transport path measures the thickness of the film 250 being molded flowing on the transport path at regular intervals. The thickness measuring unit 10 measures the thickness of the film 250 on the downstream side of the take-off roll 240. The thickness measuring unit 10 supplies an actual measured value hD of the thickness of the film 250 measured at regular intervals to the first data acquiring unit 21 (thickness measuring step S11).

  Next, the first data acquisition unit 21 creates time-series data of the thickness of the film 250 by associating the actual measurement value hD with the measurement time t. The first data acquisition unit 21 supplies this time-series data to the first data conversion unit 23 as thickness distribution data h (t) in the flow direction FR of the film 250 being conveyed in the forming unit 200 (thickness). Distribution data creation step S12).

  Next, the first data converter 23 performs Fourier transform on the thickness distribution data h (t) in the flow direction FR of the film 250 to calculate the first frequency spectrum H (f) (first data conversion). Step S13). In the first data conversion step S <b> 13, the first data conversion unit 23 performs Fourier transform on the thickness distribution data of the film 250 on the downstream side of the take-off roll 240. The Fourier transform is performed using, for example, an algorithm of Fast Fourier Transform (FFT).

  Next, the analysis unit 25 detects the peak frequency fH of the first frequency spectrum H (f). The analysis unit 25 supplies the frequency fH to the output unit 26 as first frequency information (first frequency information detection step S14). If no peak exists in the first frequency spectrum H (f), the analysis unit 25 supplies a specific numerical value to the output unit 26 as first frequency information.

  In the second analysis step S20, first, the plurality of sensors 30 respectively measure the rotation amounts rD of the plurality of rolls 290 that transport the film 250 being formed (rotation amount measurement step S21).

  The plurality of rolls 290 whose rotation amount is detected include, for example, at least one of a cast roll 220, a nip roll 230, and a take-off roll 240. In the present embodiment, the rotation amounts of the cast roll 220, the nip roll 230, and the take-off roll 240 are measured by the plurality of sensors 30.

  Next, the second data acquisition unit 22 creates time-series data regarding the rotation amount of each roll 290 by associating the measured value rD of the rotation amount of each roll 290 with the measurement time t. The second data acquisition unit 22 associates these time series data with the roll number of each roll 290. The second data acquisition unit 22 supplies a plurality of time-series data associated with the roll number to the second data conversion unit 24 as rotation amount data r (t) of the plurality of rolls 290 (rotation amount data). Creating step S22).

  Next, the second data conversion unit 24 performs Fourier transform on the rotation amount data r (t) of the plurality of rolls 290 that transport the film 250, and a plurality of second frequency spectra corresponding to the respective rolls 290. R (f) is calculated (second data conversion step S23). The Fourier transform is performed using a known fast Fourier transform algorithm.

  Next, the analysis unit 25 detects the peak frequency fR for each of the plurality of second frequency spectra R (f) corresponding to each roll 290. The analysis unit 25 supplies the frequency fR corresponding to each roll 290 to the output unit 26 as second frequency information (second frequency information detection step S24). When no peak exists in the second frequency spectrum R (f), the analysis unit 25 supplies a specific numerical value or symbol to the output unit 26 as second frequency information.

  In the third analysis step S30, first, the output unit 26 determines whether or not there is a peak in the first frequency spectrum H (f) based on the first frequency information (first determination step). S31).

  When a peak exists in the first frequency spectrum H (f) (first determination step S31: Yes), the alarm unit 41 issues an alarm (alarm step S32). As a result, the user recognizes that periodic thickness unevenness has occurred in the film 250. The user performs follow-up for a while after the alarm is issued (see follow-up step S4 in FIG. 3).

  When no peak exists in the first frequency spectrum H (f) (first determination step S31: No), the formation of the film 250 is continued.

  When a peak exists in the first frequency spectrum H (f), the output unit 26 includes the first frequency spectrum H (f) in the plurality of second frequency spectra R (f) corresponding to each roll 290. It is determined whether there is a peak with the same frequency as () (second determination step S33).

  In the specific second frequency spectrum R (f), when there is a peak at the same frequency as the first frequency spectrum H (f) (second determination step S33: Yes), the information presentation unit 42 Information indicating the roll 290 corresponding to the second frequency spectrum R (f) is presented (information presentation step S34). Thereby, the user recognizes the roll 290 that causes periodic thickness unevenness of the film 250. In the maintenance step S5 of FIG. 3, the worker inspects the roll 290 for which information is presented for the presence of malfunction.

  When a peak having the same frequency as the first frequency spectrum H (f) does not exist in the plurality of second frequency spectra R (f) (second determination step S33: No), the sensor 30 is not installed. It is presumed that a malfunction occurred in the roll 290 or the T-die 210. In the maintenance step S5 of FIG. 3, the operator inspects the other rolls 290 or the T-die 210 on which the sensor 30 is not installed for malfunction.

  FIG. 5 is a diagram showing a first frequency spectrum H (f) of the thickness distribution of the film 250 when a malfunction occurs in the cast roll 220. FIG. 6 is a diagram illustrating a second frequency spectrum R (f) of the rotation amount of the cast roll 220 when an operation failure occurs in the cast roll 220. FIG. 7 is a diagram illustrating a first frequency spectrum H (f) of the thickness distribution of the film 250 when no periodic thickness unevenness occurs in the film 250. 8 to 10 are diagrams showing second frequency spectra R (f) of the rotation amounts of the cast roll 220, the nip roll 230, and the take-off roll 240 when no periodic thickness unevenness occurs in the film 250, respectively. is there.

  As shown in FIGS. 5 and 6, the first frequency spectrum H (f) and the second frequency spectrum R (f) have peaks at the same frequency. As shown in FIGS. 7 to 10, when the thickness unevenness does not occur in the film 250, no periodic fluctuations occur in the rotation amounts of the cast roll 220, the nip roll 230, and the take-off roll 240. From these facts, it can be seen that there is a strong correlation between the fluctuation period of the rotation amount of the roll 290 and the fluctuation period of the thickness of the film 250.

  As described above, according to the inspection method of this embodiment, the periodic thickness unevenness of the film 250 is constantly monitored using the frequency analysis technique. Therefore, the periodic thickness unevenness of the film 250 can be detected at an early stage, and prompt response to a machine trouble can be promoted.

  In this embodiment, when the frequency at which the peak occurs in the specific second frequency spectrum R (f) matches the first frequency spectrum, the roll 290 corresponding to the specific second frequency spectrum R (f). Information pointing to is presented. Therefore, the roll 290 that causes the uneven thickness of the film 250 can be easily identified.

  In the present embodiment, a change in the rotation amount of at least one of the cast roll 220, the nip roll 230, and the take-off roll 240 is monitored. The periodic thickness unevenness of the film 250 is mainly caused by fluctuations in the rotation amount of the cast roll 220, the nip roll 230, or the take-off roll 240. Therefore, by monitoring the rotation amount of these rolls, it is possible to quickly cope with machine troubles.

  In the present embodiment, the thickness distribution data h (t) of the film 250 on the downstream side of the take-off roll 240 is subjected to Fourier transform. By monitoring the thickness distribution of the film 250 that has passed through the cast roll, nip roll, and take-off roll, it is possible to monitor fluctuations in the rotation amount of these rolls that are likely to cause periodic thickness unevenness of the film 250.

[Second Embodiment]
FIG. 11 is a view of the thickness measuring unit 60 according to the second embodiment as viewed from above the conveyance path of the film 250. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  This embodiment is different from the first embodiment in that the thickness measuring unit 60 measures the thickness at a plurality of positions in the film width direction.

  The thickness measuring unit 60 includes, for example, a plurality of thickness gauges 18. The plurality of thickness gauges 18 are attached to a construction member 19 that crosses the conveyance path, for example. The plurality of thickness gauges 18 are installed at different positions in the film width direction orthogonal to the flow direction FR. The plurality of thickness gauges 18 are respectively provided corresponding to the plurality of inspection lines DL set in the film width direction. The plurality of thickness gauges 18 supplies the measured value hD of the thickness of the film 250 along different inspection lines DL to the processing unit 20.

  Hereinafter, when distinguishing a plurality of inspection lines DL, a number is added to the end of the code of each inspection line DL. The same applies to the case where the actual measurement value hD corresponding to each inspection line DL and the machining data of the actual measurement value hD are distinguished.

  In the present embodiment, for example, as the plurality of thickness gauges 18, a first thickness gauge 11, a second thickness gauge 12, and a third thickness gauge 13 are provided. The erection member 19 includes, for example, a first guide rail 14 and a second guide rail 15. The first guide rail 14 holds the first thickness gauge 11 so as to be slidable in the film width direction. The second guide rail 15 holds the second thickness gauge 12 and the second thickness gauge 13 so as to be slidable in the film width direction.

First thickness meter 11 is disposed in a central portion of the film width direction, and supplies the measured value hD ₁ of the thickness of the first inspection line DL ₁ to along the film 250 to the first data acquisition unit 21. Second thickness meter 12 is disposed at a first end of the film 250, and supplies the measured value hD ₂ of the thickness of the second inspection line DL ₂ in along the film 250 to the first data acquisition unit 21. Third thickness meter 13 is disposed at a second end of the film 250, and supplies the measured value hD ₃ of the thickness of the film 250 along the third inspection line DL ₃ to the first data acquisition unit 21.

  The first data acquisition unit 21 creates time-series data of the thickness of the film 250 corresponding to each inspection line DL by associating the measured value hD of the thickness of the film 250 in each inspection line DL with the measurement time t. . The first data acquisition unit 21 supplies these time series data to the first data conversion unit 23 as thickness distribution data h (t) in each inspection line DL.

  The first data conversion unit 23 Fourier-transforms the thickness distribution data h (t) in the plurality of inspection lines DL parallel to the flow direction FR, and a plurality of first frequency spectra corresponding to the inspection lines DL. H (f) is calculated. The first data conversion unit 23 supplies a plurality of first frequency spectra H (f) corresponding to each inspection line DL to the analysis unit 25, respectively.

  The analysis unit 25 detects the peak frequency fH of each first frequency spectrum H (f). The analysis unit 25 supplies the plurality of frequencies fH detected for each of the plurality of first frequency spectra H (f) to the output unit 26 as first frequency information. When no peak exists in the first frequency spectrum H (f), the analysis unit 25 sets, for example, a specific numerical value (for example, 0) as the frequency fH.

  The output unit 26 determines whether or not there is a peak in each first frequency spectrum H (f) based on the first frequency information. The output unit 26 supplies information related to whether or not a peak exists in each first frequency spectrum H (f) to the alarm unit 41 as first output information IO1. The alarm unit 41 issues an alarm when a peak exists in at least one first frequency spectrum H (f).

  As described above, in the inspection method of the present embodiment, a plurality of inspection lines DL are set in the film width direction, and the thickness distribution of the film 250 is measured along each inspection line DL. Therefore, even if it is difficult to detect the peak of the first frequency spectrum H (f) on the specific inspection line DL, the periodic thickness unevenness of the film 250 can be reliably detected.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment. The content disclosed in the embodiment is merely an example, and various modifications can be made without departing from the spirit of the present invention. Appropriate changes made without departing from the spirit of the present invention naturally belong to the technical scope of the present invention. All the inventions that can be implemented by those skilled in the art based on the above-described inventions are also within the technical scope of the present invention as long as they include the gist of the present invention.

  For example, in the above-described embodiment, the rotation amounts of the cast roll 220, the nip roll 230, and the take-off roll 240 are measured by the plurality of sensors 30, respectively. However, the roll for measuring the rotation amount is not limited to the cast roll 220, the nip roll 230, and the take-off roll 240. For example, the rotation amount of the stretching roll and the touch roll of the film 250 may be measured.

  In the above-described embodiment, the example in which the film 250 is formed of a single resin has been described. However, the film 250 may contain materials other than resin. For example, the film 250 may be a composite or laminate of a resin and a metal material or an inorganic material.

  In general, a “film” is a thin flat product that is extremely small compared to its length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll (Japan). Industrial standard JISK6900). In general, the term “sheet” refers to a product that is thin according to the definition in JIS and generally has a small thickness and a flatness instead of length and width. However, the boundary between the film and the sheet is not clear. In the present specification, both are used as terms having the same meaning, and both are unified and referred to as “film”.

DESCRIPTION OF SYMBOLS 1 Film manufacturing apparatus 23 1st data conversion part 24 2nd data conversion part 41 Alarm part 42 Information presentation part 100 Inspection part (inspection apparatus)
200 Forming part 220 Cast roll 230 Nip roll 240 Take-off roll 250 Film 250a Resin 290 Roll DL Inspection line FR Flow direction

Claims (8)

A first data conversion step of Fourier transforming the thickness distribution data in the film flow direction to calculate a first frequency spectrum;
An alarm step for issuing an alarm when a peak is present in the first frequency spectrum;
A second data conversion step of Fourier-transforming the rotation amount data of a plurality of rolls carrying the film, and calculating a plurality of second frequency spectra corresponding to the respective rolls;
An information presentation step for presenting information indicating the roll corresponding to the second frequency spectrum in which a frequency at which a peak occurs coincides with the first frequency spectrum;
Inspection method having The plurality of rolls include: a cast roll to which a resin that is a raw material of the film is attached; a nip roll that sandwiches the resin between the cast rolls; and a take-off roll that receives the resin attached to the cast roll. The inspection method according to claim 1, wherein at least one of the rolls is included. The inspection method according to claim 2, wherein in the first data conversion step, the thickness distribution data of the film on the downstream side of the take-off roll is Fourier-transformed. In the first data conversion step, each of the thickness distribution data in a plurality of inspection lines parallel to the flow direction is Fourier transformed to calculate a plurality of the first frequency spectra corresponding to each inspection line,
The inspection method according to claim 1, wherein in the alarm step, an alarm is issued when a peak exists in at least one of the first frequency spectra. A molding step of transporting the film while molding;
A first data conversion step of calculating a first frequency spectrum by Fourier transforming the thickness distribution data in the flow direction of the film being conveyed;
An alarm step for issuing an alarm when a peak is present in the first frequency spectrum;
A second data conversion step of Fourier-transforming the rotation amount data of a plurality of rolls carrying the film, and calculating a plurality of second frequency spectra corresponding to the respective rolls;
An information presentation step for presenting information indicating the roll corresponding to the second frequency spectrum in which a frequency at which a peak occurs coincides with the first frequency spectrum;
A method for producing a film. A first data conversion unit for calculating a first frequency spectrum by Fourier transforming the thickness distribution data in the film flow direction;
An alarm unit that issues an alarm when a peak exists in the first frequency spectrum;
A second data conversion unit that performs Fourier transform on the rotation amount data of a plurality of rolls that transport the film, and calculates a plurality of second frequency spectra corresponding to the respective rolls,
An information presentation unit for presenting information indicating the roll corresponding to the second frequency spectrum in which a frequency at which a peak occurs matches the first frequency spectrum;
Inspection device having A molding section for conveying the film while molding;
A first data converter for calculating a first frequency spectrum by Fourier transforming the thickness distribution data in the flow direction of the film being conveyed;
An alarm unit that issues an alarm when a peak exists in the first frequency spectrum;
A second data conversion unit that performs Fourier transform on the rotation amount data of a plurality of rolls that transport the film, and calculates a plurality of second frequency spectra corresponding to the respective rolls,
An information presentation unit for presenting information indicating the roll corresponding to the second frequency spectrum in which a frequency at which a peak occurs matches the first frequency spectrum;
A film manufacturing apparatus comprising: A first data conversion step of Fourier transforming the thickness distribution data in the film flow direction to calculate a first frequency spectrum;
An alarm step for issuing an alarm when a peak is present in the first frequency spectrum;
A second data conversion step of Fourier-transforming the rotation amount data of a plurality of rolls carrying the film, and calculating a plurality of second frequency spectra corresponding to the respective rolls;
An information presentation step for presenting information indicating the roll corresponding to the second frequency spectrum in which a frequency at which a peak occurs coincides with the first frequency spectrum;
Inspection program that causes a computer to execute.

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