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CN-122015668-A - Method and system for measuring thickness of material in film blowing production line

CN122015668ACN 122015668 ACN122015668 ACN 122015668ACN-122015668-A

Abstract

The application relates to the technical field of tube film thickness measurement, in particular to a method and a system for measuring the thickness of a tube film material in a film blowing production line, which comprises the steps of aligning and flattening the tube film to obtain a double-layer film when the tube film blown by a film blowing machine enters a traction flattening roller, carrying out continuous scanning measurement along the film advancing direction by adopting a thickness gauge based on the double-layer film to obtain a double-layer thickness data sequence, collecting rotation phase data of the film blowing machine in real time, and based on the double-layer thickness data sequence, determining the circumferential point alignment relation of the double-layer film corresponding to each thickness measurement moment, obtaining an overdetermined observation equation set based on the circumferential point alignment relation and corresponding double-layer thickness data, and performing data solving to obtain the thickness value of each single-layer point in the circumferential direction of the tubular film, thereby solving the problems that the alignment relation is uncertain due to dynamic rotation in the prior art, a thickness gauge cannot accurately measure the double-layer measured value to the corresponding single-layer point, and the single-layer thickness distribution accuracy is reduced.

Inventors

  • ZHOU HONGJUN

Assignees

  • 无锡动视宫原科技有限公司

Dates

Publication Date
20260512
Application Date
20260212

Claims (10)

  1. 1. A film blowing line material thickness measurement method, comprising: when a tubular film blown by a film blowing machine enters a traction flattening roller, aligning and flattening the tubular film to obtain a double-layer film; Based on the double-layer film, adopting a thickness gauge to perform continuous scanning measurement along the film travelling direction to obtain a double-layer thickness data sequence; acquiring rotation phase data of the film blowing machine in real time, and determining circumferential point position alignment relation of the double-layer film corresponding to each thickness measurement moment based on the double-layer thickness data sequence; obtaining an overdetermined observation equation set based on the circumferential point position alignment relation and the corresponding double-layer thickness data; And carrying out mathematical solution on the overdetermined observation equation set to obtain thickness values of each single-layer point position of the tubular film in the circumferential direction.
  2. 2. The method for measuring the thickness of a blown film production line material according to claim 1, wherein the continuous scanning measurement is performed along the film travelling direction by using a thickness gauge based on the double-layer film to obtain a double-layer thickness data sequence, comprising: driving a thickness gauge to perform reciprocating scanning in the width direction of the double-layer film at a preset fixed frequency, and performing equidistant sampling along the film advancing direction in each scanning period to obtain a thickness measuring point set; and correlating each thickness measurement point with the corresponding sampling time and the position coordinate of the probe in the width direction of the film to obtain a double-layer thickness data sequence.
  3. 3. The blown film line thickness measurement method according to claim 1, wherein determining a circumferential point alignment relationship of the bilayer film corresponding to each thickness measurement time based on the bilayer thickness data sequence comprises: equally dividing the circumference of the tubular film into a plurality of discrete points; establishing a mapping function of the rotation phase data and the discrete point positions; Inquiring rotation phase data at corresponding time based on the sampling time of each data point in the double-layer thickness data sequence; and obtaining the circumferential point alignment relation corresponding to each sampling time according to the rotation phase data at the corresponding time and the mapping function.
  4. 4. A blown film line thickness measurement method according to claim 3, wherein said establishing a mapping function of said rotational phase data and said discrete points comprises: the phase inversion data comprises a die rotation angle; Determining the actual phase of each point on the die head in the film blowing machine at the current moment according to the die head rotation angle and the total number of the discrete point positions; based on the actual phase, compensating by combining known advancing time of the tubular film from the outlet of the film blowing die head to the measuring position of the thickness gauge and a preset film stretching rate, and obtaining a compensating phase of a film point position at the measuring position of the thickness gauge; Matching the compensation phase with discrete points of the circumference of the tubular film to obtain a plurality of pairs of aligned circumferential point numbers; and establishing a mapping function based on the multi-aligned circumferential point position numbers.
  5. 5. The blown film line thickness measurement method according to claim 4, wherein said establishing a mapping function based on said plurality of aligned circumferential point locations numbers further comprises: setting optical mark points on the tubular section of the tubular film before the tubular film enters the traction flattening roller; continuously capturing the actual positions of the optical mark points; comparing the actual position with a preset theoretical position to obtain position deviation; and adjusting the mapping function based on the position deviation.
  6. 6. The blown film line thickness measurement method according to claim 3, wherein the obtaining the overdetermined observation equation set based on the circumferential point alignment relation and the corresponding bilayer thickness data further comprises: Acquiring temperature distribution data of the double-layer film at a measuring position of a thickness gauge in real time; And carrying out thermal expansion compensation correction on the original measured value in the double-layer thickness data sequence based on the temperature distribution data and a preset material thermal expansion coefficient to obtain a corrected double-layer thickness data sequence.
  7. 7. A blown film line thickness measurement method according to claim 3, wherein the obtaining an overdetermined observation equation set based on the circumferential point alignment relation and the corresponding bilayer thickness data comprises: Defining the thickness of the monolayer film corresponding to each discrete point as an unknown variable; establishing a linear equation aiming at each pair of circumferential point alignment relations and corresponding double-layer thickness measurement values; And summarizing the linear equations established at all measurement moments to form a linear equation set serving as an overdetermined observation equation set.
  8. 8. A blown film line thickness measurement system, comprising: A film blowing machine for blowing a tubular film; a flattening traction unit for flattening the tubular film into a double-layer film when the tubular film is detected; The thickness gauge is arranged at the downstream of the flattening traction unit and is used for continuously scanning and measuring the double-layer film along the film travelling direction to obtain a double-layer thickness data sequence; the rotary phase sensor is arranged on a rotary component of the film blowing machine and used for collecting rotary phase data in real time; The data processing and control unit is respectively in communication connection with the thickness gauge and the rotation phase sensor and performs the following steps: Receiving the bilayer thickness data sequence and the rotational phase data; determining the circumferential point alignment relationship corresponding to each measurement time; Constructing an overdetermined observation equation set based on the circumferential point position alignment relation and the corresponding double-layer thickness data, and solving; Outputting the thickness value of each single-layer point position of the tubular film in the circumferential direction.
  9. 9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program which, when executed by the processor, causes the processor to perform the steps of the blown film production line thickness measurement method according to any one of claims 1 to 7.
  10. 10. A computer-readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed, implements the blown film line material thickness measurement method according to any one of claims 1-7.

Description

Method and system for measuring thickness of material in film blowing production line Technical Field The application relates to the technical field of pipe film thickness measurement, in particular to a method and a system for measuring the thickness of a material in a film blowing production line. Background With the continuous expansion of the application fields of packaging, agriculture and industrial films, the quality requirements on blown film products are increasingly improved, wherein the uniformity of the thickness of the film is a key index for influencing the mechanical property, the optical property and the barrier property of the film. In order to realize high-precision thickness control, a film blowing production line is commonly provided with a thickness measuring system, in particular to a non-contact thickness meter based on an optical principle (such as laser, infrared interference and the like), and the film blowing production line is widely applied due to high response speed and high precision. In the existing optical thickness measurement method, after a tubular film is pulled and flattened to form a double-layer film, transverse scanning measurement is directly carried out on the flattened film, and total thickness data of the flattened film are obtained. However, in the film blowing process, in order to achieve uniformity of film thickness, the film blowing die is often designed in a rotatable structure, which causes the distribution of material on the circumference of the tubular film after forming to be in a continuously rotating and varying state with respect to the die outlet position. When the tubular film having the rotation phase variation is flattened, at any measurement time, the upper and lower films constituting the total thickness of the double-layered film are dynamically varied, not fixedly varied, respectively corresponding to specific points on the circumference of the original tubular film. The optical thickness measurement scheme described in the prior art mostly ignores the dynamic change characteristic of the flattening alignment point caused by the rotation of the die head, thereby causing fundamental measurement principle errors, namely, combining the dynamically-changed random upper and lower layer thicknesses to be mistakenly considered as a simple superposition of two layers with fixed alignment and equal thicknesses. Therefore, even if a high-precision optical thickness gauge is used, the double-layer thickness data directly output by the optical thickness gauge cannot accurately reflect the actual single-layer thickness distribution of the original tubular film in the circumferential direction. Such distortions mask critical information of film circumferential non-uniformity, such that process adjustments (e.g., die gap adjustments) based on such measurement data lose accurate basis and are difficult to meet the fine control requirements of high end film fabrication for thickness uniformity. Disclosure of Invention In view of the above, the application provides a method and a system for measuring the thickness of a material in a film blowing production line, which are used for synchronously collecting dynamic alignment relation and double-layer thickness data after film flattening, and constructing and solving an overdetermined observation equation set, so that the measurement accuracy of the thickness distribution of each single-layer point position of a tubular film in the circumferential direction is improved on the premise of keeping the advantages of non-contact and continuous optical thickness measurement, and the technical problems that the alignment relation is uncertain due to dynamic rotation in the prior art, a thickness gauge cannot accurately measure double-layer measured values to corresponding single-layer point positions and the single-layer thickness distribution accuracy is reduced are solved. The application provides a method and a system for measuring the thickness of a material of a film blowing production line, which adopts the following technical scheme: A film blowing production line material thickness measuring method comprises the following steps: When the tubular film blown by the film blowing machine enters a traction flattening roller, aligning and flattening the tubular film to obtain a double-layer film; based on the double-layer film, adopting a thickness gauge to perform continuous scanning measurement along the film travelling direction to obtain a double-layer thickness data sequence; acquiring rotation phase data of the film blowing machine in real time, and determining circumferential point alignment relations of the double-layer film corresponding to each thickness measurement moment based on the double-layer thickness data sequence; Obtaining an overdetermined observation equation set based on the circumferential point position alignment relation and the corresponding double-layer thickness data; and carrying out mathe