Apparatus for measuring the thickness of a continuous material web
Patent Information
- Application Number
- JP2024519038
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2021-09-23
- Filing Date
- 2022-08-26
- Publication Date
- 2025-06-05
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to an apparatus for continuous, in particular non-contact thickness measurement of flexible, elastic and / or coated material webs, which comprises: the material web being guided, in particular at least partially, on the surface of a cylindrical contact body; The sensor device includes a sensor arrangement for measuring the thickness of the material web, the sensor arrangement including at least one first sensor directed toward a top surface of the material web and at least one second sensor directed toward a bottom surface of the material web opposite the first sensor. [Background technology]
[0002] From the document German patent application no. 10 2019 121959 B4 a method for producing a plastic film is known, in which molten plastic material is discharged in the conveying direction from a flat nozzle and then cooled, the flat nozzle having several nozzle bolts adjacent to one another in the width direction of the plastic film. A measuring device for measuring the thickness of the produced plastic film is arranged in the conveying direction behind the flat nozzle, since this can affect the size of the discharge gap of the molten plastic material. However, the measuring device for measuring the thickness of the film is arranged in the conveying direction behind the lift roller. This arrangement has the disadvantage that the film floats freely at the measuring site, which is not provided with a support device, and therefore vibrations and fluctuations can occur, which can distort the measurement result.
[0003] From the document European Patent Application No. 0 472 872 A3 a method and an apparatus are known for determining the thickness of a coating applied to a web by a coating device. The thickness of the coating applied to a carrier web on a coating roller is measured in front of and behind the contact area between the coating roller and the web to be coated, and the thickness of the coating divided by the thickness of the web is determined from the difference in the measured film thicknesses. However, the disclosed apparatus has the disadvantage that the measurement result depends on the concentricity and vibration of the coating roller. Summary of the Invention [Problem to be solved by the invention]
[0004] The invention is therefore based on the object of improving an apparatus or method for measuring film thickness in such a way that more accurate measurement results are obtained.
[0005] This object is achieved by a device or a method having the features of the present independent claims. [Means for solving the problem]
[0006] The second sensor is therefore arranged at least partially under the contact area between the material web and the contact body. The invention thus has the advantage that on the one hand the film is supported by the contact body in the area of the thickness measurement and on the other hand vibrations of the film are avoided. The influencing variables induced by the contact body are also automatically calculated by simultaneously measuring the film thickness on the upper and lower sides of the film. The contact body may have a flat contact area. The contact body may also have an at least partially convex contact area. In particular, the lower side of the material web is guided past the surface of the contact body in the contact area. The material web may be deflected through the contact area to a predefined extent, so that the material web before the contact area and the material web after the contact area form an angle of more than 0°. In particular, the material web in the area of the thickness measurement may be at least partially supported by the contact body. The material web may in particular be a flexible, elastic and / or coated film. The range of the thickness measurement may be defined by the overlapping detection ranges of the mutually opposing sensors. A plurality of opposing pairs of sensors may be arranged across the width of the material web. In particular, a sensor of each pair may be arranged at least partially under a contact area between the material web and the contact body. The sensors may be designed to measure distances. A first sensor may be formed for detecting a distance between the first sensor and a top surface of the material web, and a second sensor may be formed for detecting a distance between the second sensor and a bottom surface of the material web. The first and second sensors may be arranged at a predetermined distance from each other.
[0007] The thickness of the material web can therefore be calculated from the difference between the predetermined distance of the sensors relative to each other and the sum of the two measured distances of the first and second sensor.
[0008] The second sensor may at least partially overlap the cross-section of the cylindrical roller body and be disposed between the axle and the surface of the cylindrical roller body. The second sensor may be located completely within the cross-sectional area of the cylindrical roller body.
[0009] The detection area of the second sensor may also at least partially include the lower surface of the contact body, in particular the inner surface of the cylindrical roller body. The detection device of the second sensor may face the lower or inner surface of the contact body. The detection device of the first sensor may be directed towards the upper surface of the material web. The detection range of the first sensor and the detection range of the second sensor may be diametrically opposed to each other.
[0010] In addition, the cylindrical roller body may have a cavity in which the second sensor is accommodated. The cavity may be dimensioned such that the second sensor in the cylindrical roller body may be stationary without contacting the cylindrical roller body that rotates around the second sensor. Furthermore, the cylindrical roller body may be sleeve-shaped. The cylindrical roller body may be rotatably mounted such that the moving material web rolls over it without any particular slippage. The cylindrical roller body may be manufactured by a galvanizing process.
[0011] The surface of the cylindrical roller body may have at least one penetration at least partially within the detection range of the second sensor. The material web may be guided past the penetration. It may be intended that the penetration leads to a cavity.
[0012] The perforations may also extend substantially tangentially along the surface of the cylindrical roller body, so that the perforations extend in the direction of movement of the material web along the material web extending past the perforations. The perforations may have a width of more than 0.5 cm. The perforations may be recesses in the material of the cylindrical roller body.
[0013] In addition, the perforations may extend with at least one interruption around the entire circumference of the cylindrical roller body. The perforations may in particular be periodically spaced and have two, three or four interruptions. Each of the perforations distributed on the circumference may have the same length. The interruptions may be characterized in that at least one material web of the cylindrical roller body is fed into this area, thereby stabilizing the structure of the cylindrical roller body.
[0014] The surface of the cylindrical roller body may have a plurality of parallel spaced apart perforations. The distance between the perforations may be the same. The perforations may be spaced apart from one another by bar-like spacers. The perforations may have a width greater than that of the web-like spacing elements.
[0015] The surface of the contact body, in particular the cylindrical roller body, may also have a sieve structure. The sieve structure may have a plurality of penetrations, particularly regularly distributed, on the surface of the contact body, in particular the cylindrical roller body. The penetrations may be elongated. The penetrations may be circular. The penetrations may be elliptical. The penetrations may be angled. The penetrations may be square. The penetrations may be rectangular. The penetrations may be quadrilateral. The penetrations may be honeycomb-shaped. The area ratio of the penetrations to the total surface area of the contact body may be more than 50%, preferably more than 60%, particularly preferably more than 70%.
[0016] In addition, the sensor can be mounted on at least one linear guide that can be adjusted transversely to the direction of movement of the material web. The linear guide can be electrically adjusted. The linear guide can also be provided with means for manual adjustment. The linear guide allows the sensor device to be adjusted transversely to the direction of movement of the material web to perform thickness measurements at various positions on the material web. The device can have a control device that can control the linear guide. For example, the sensor assembly can include two sensor pairs that can be arranged spaced apart from each other and perpendicular to the direction of movement of the material web and are linearly adjustable perpendicular to the material web. If the sensor pair of the sensor device detects a deviation in a predetermined or desired material thickness, the linear guide can be controlled such that the sensor device is adjusted transversely in the direction of the detected deviation. Furthermore, the control can include initiating an emergency stop when a maximum allowable deviation thickness is exceeded, for example stopping the supply of further material.
[0017] Furthermore, the cylindrical roller body may be mounted at its end faces via thin ring bearings, or alternatively, any additional bearings that ensure high concentricity accuracy may be used to support the cylindrical roller body.
[0018] Furthermore, the sensor may be arranged stationary relative to the direction of travel of the material web, which allows the sensor assembly to continuously detect the thickness of the passing material web. Furthermore, the sensor may be adjusted continuously or discontinuously transversely to the direction of travel of the material web. The sensor assembly may be adjusted in one direction until the outer edge of the material web is reached, and then adjusted in the opposite direction until the opposite edge of the material web is reached.
[0019] The invention also relates to a method for non-contact thickness measurement, in particular of a flexible, elastic and / or coated material web, comprising: Guiding the material web onto a contact body, which is in particular at least partially cylindrical; simultaneously detecting a top surface of the material web with a first sensor and a bottom surface of the material web with a second sensor, the detection ranges of both sensors being aligned with each other and the second sensor being positioned at least partially under a contact area between the material web and the contact body; Using the obtained sensor values of the first and second sensors to determine a thickness of the web of material.
[0020] The material web can be deflected by the contact body, the deflection of which can be such that the material web is supported by the contact body in the contact area and vibrations of the material web can be reliably avoided. [Brief description of the drawings]
[0021] Exemplary embodiments of the present invention are described with reference to the following figures.
[0022] [Figure 1] 1A and 1B show a cross-sectional view of a first method known from the prior art for detecting the thickness of a material web, and a cross-sectional view of a second method known from the prior art for detecting the thickness of a material web. [Diagram 2] 3A and 3B show a cross-sectional view of a third method known from the prior art for detecting the thickness of a material web, and a fourth method known from the prior art for detecting the thickness of a web. [Diagram 3] 3 shows a cross section of an embodiment of the method according to the invention for detecting the thickness of a material web. [Figure 4] 1 shows a perspective view of a sensor device according to the invention for detecting the thickness of a material web; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] 1a and 1b show an apparatus 1 for continuous thickness measurement, in which a thickness measurement of a material web 2 is performed by means of a light curtain 12, the shadowed area 13 caused by the material web being the basis for determining the thickness t of the material web. In FIG. 1a, the sensor arrangement 4 is arranged so that the light curtain 12 is flush with the upper surface of the roller 3, over which the material web 2 is guided so that the roller 3 does not directly block the light curtain 12. When the material web is guided into the detection area of the sensor assembly 4, the material web 2 protruding from the upper surface of the roller blocks the light curtain 12, so that the material thickness t of the material web 2 corresponds to the width of the shadowed area 13. The previously recorded run-out characteristic of the roller is subtracted from this. However, a disadvantage of this apparatus is that the thickness of the material web can only be calculated indirectly from the concentricity topography of the roller 3. If the movement characteristic of the roller 3 changes for any reason, measurement tolerances arise.
[0024] Fig. 1b shows a detection method for determining the thickness t of the material web 2, slightly modified compared to the configuration of Fig. 1a. In this detection method, the sensor device 4 is arranged in such a way that the light curtain 12 beyond the material web also detects the edge of the roller 3, so that a defined shaded area 13 always results, even if the material web 2 is not present. However, the disadvantage of this method is that the tolerances of the roller 3 are always included in the measurement tolerances, so that in this case the thickness t of the material web 2 can only be derived indirectly from the measurement result. The tolerances of the roller 3 are determined by the deviations in concentricity and cylindricity of the measurement points next to the material web 2 and on the material web 2.
[0025] 2a and 2b show two further methods known from the prior art for detecting the thickness t of a material web 2. The structure of FIG. 2a comprises a sensor device 4 oriented perpendicularly to the material web 2, which is guided in the material movement direction X by a rotating roller 3. The material thickness t is determined by triangulation, in which a light ray emitted by the sensor is reflected at the top surface 7 of the material and at the bottom surface 8 of the other material, the thickness t of the material corresponding to the displacement difference of the different reflected light rays. The stored runout characteristic of the roller is subtracted. However, the disadvantage of this device is also that the thickness t of the material web can only be calculated indirectly from the concentricity topography of the roller 3. If the movement characteristic of the roller 3 changes for any reason, measurement tolerances arise.
[0026] In contrast, the arrangement shown in Fig. 2b comprises two deflection rollers 3, through which the material web 2 passes continuously. A sensor assembly 4 is arranged between the deflection rollers 3, which comprises a first sensor 5 directed towards the top surface 7 of the material web and a sensor 6 directed towards the bottom surface 8 of the material web, each of which is arranged perpendicular to the material web 2 and the detection areas of both sensors 5, 6 are aligned. However, a disadvantage of this arrangement is that a free-floating material web is prone to vibrations or wobble. A smooth movement is hindered by the tolerances of the material web.
[0027] FIG. 3 shows a cross-sectional view of an embodiment of the inventive device 1 for non-contact thickness measurement, in particular of flexible, elastic and / or coated material webs 2. The device comprises a cylindrical roller body 3, which is sleeve-shaped and has a continuous cavity 9. The roller body 3 has a circular cross section A and a rotation axis R. The material web 2 is guided in the moving direction X by the outer upper surface of the cylindrical roller body 3, which deflects the material web 2 and rolls over it without slipping. The device 1 further comprises a sensor device 4 with a first sensor 5 directed towards the material web upper surface 7 and a second sensor 6 directed towards the material web bottom surface 8. The sensor comprises a detection device, the detection direction of which is perpendicular to the surface or bottom surface of the material. The detection ranges of both sensors 5, 6 are precisely aligned with one another such that the thickness t of the material web 2 is measured perpendicular to its main propagation direction. The second sensor 6 is arranged in a cavity 9 of the cylindrical roller body 3 and is located between the outer circumference of the cylindrical roller device 3 and its rotation axis R. The cylindrical roller body 3 has a number of penetrations 10 on its surface, each of which leads into the cavity 9. The penetrations 10 extend essentially tangentially along the surface of the roller body 3, so that when the cylindrical roller body 3 rotates, the detection area of the sensor 6 detects the bottom surface 8 of the material web via the penetrations 10 over a maximum time or circumferential part of the cylindrical roller body 3. The cylindrical roller body 3 is therefore essentially a sleeve with a sieve structure. The cylindrical roller body 3 has a high concentricity accuracy and can be produced by a galvanizing process. A great advantage of the device according to the invention is therefore that the material web 2 is supported in the detection ranges of both sensors 5, 6 by the cylindrical roller body 3, so that vibrations cannot occur as with a free-floating material web. At the same time, since detection is carried out simultaneously on the top surface 7 and on the bottom surface 8 of the material web 2, any errors in the concentricity of the cylindrical roller body 3 can always be eliminated.
[0028] FIG. 4 shows a perspective view of an embodiment of the device 1 according to the invention. As can be seen from the figure, the cylindrical roller body 3 is formed in the form of a sleeve with a number of uniform penetrations 10. The sleeve 3 has a rotation axis R and is mounted at its front side via a thin ring bearing, not shown. The sleeve 3 is adapted to move or rotate in a movement direction X. For the sake of clarity, the material path 2 is not shown in the figure. The penetrations 10 are designed in such a way that six equally spaced slots are distributed over the circumference of the sleeve 3, which are spaced apart from one another by short material webs. The sleeve has a number of penetrations 10 distributed over its circumference in the axial movement direction, which penetrations are each regularly spaced apart from one another in the transverse direction. The penetrations 10 each further extend perpendicularly to the rotation axis R. The sleeve 3 encloses a cross section A and has a cavity 9. The sensor assembly 4 is mounted on a sensor carrier 17, which engages the sleeve 3 over its edge area in a U-shape by means of carrier arms 18, with two first sensors 5 mounted on the sensor carrier 17, laterally spaced apart from one another, directed towards the outer surface of the sleeve 3, and two second sensors 6, laterally spaced apart opposite the first sensors 5, directed towards the inner surface of the sleeve 3. In this case, the first sensors 5 are respectively mounted on the outer carrier arms 18 and the second sensors 6 are respectively mounted on the inner carrier arms 18. The sensor carrier 17, which is guided via linear guides 11 transversely to the moving direction X of the material web 2, can be adjusted laterally. The handles 14 are attached to both ends of the sensor carrier 17. As a result, the two sensor pairs can be adjusted over the entire width of the material web 2 so that thickness measurements can be performed at any position. The linear guides 11 via hinges 16 are also hinged to covers 15 which can be folded to darken the detection area for improved sensor accuracy during operation. Each cover 15 has a handle 14 for manipulating the cover 15.
[0029] The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for the implementation of the invention both individually and in any combination.
[0030] Reference Code List 1. Apparatus for non-contact thickness measurement 2. Material Web 3. Cylindrical roller body 4. Sensor Device 5. First Sensor 6. Second Sensor 7. Material web top surface 8. Bottom of material web 9. Cavity 10. Penetration 11. Linear guides 12. Light Curtain 13. Shadow 14. Handle 15. Cover 16. Hinge 17. Sensor Carrier 18. Carrier arm A cross section t material web thickness R rotation axis X Direction of material web movement
Claims
1. An apparatus for non-contact thickness measurement of a continuous, particularly flexible, elastic, and / or coated material web, comprising: A material web guided at least in part on the surface of a contact body, which is at least partially cylindrical; A sensor assembly for measuring the thickness (t) of the material web, the sensor assembly having at least one first sensor directed towards the upper surface of the material web and at least one second sensor directed towards the bottom surface of the material web on the opposite side of the first sensor; The apparatus according to claim 1, characterized in that the second sensor is at least partially arranged below the contact area between the material web and the contact body.
2. The apparatus according to claim 1, characterized in that the second sensor at least partially overlaps the cross-section (A) of the cylindrical roller body and is arranged between the axis of rotation (R) and the surface of the cylindrical roller body.
3. The apparatus according to claim 1, characterized in that the detection area of the second sensor at least partially includes the back surface of the contact body, particularly the inner surface of the cylindrical roller body.
4. The apparatus according to claim 1, characterized in that the cylindrical roller body has a cavity in which the second sensor is accommodated.
5. The apparatus according to claim 1, characterized in that the cylindrical roller body is formed in a sleeve-like shape.
6. The apparatus according to claim 1, characterized in that the surface of the contact body, particularly the surface of the cylindrical roller body, has at least one through-hole in at least a part of the detection area of the second sensor.
7. The apparatus according to claim 6, characterized in that the through-hole extends substantially in a tangential direction along the surface of the cylindrical roller body.
8. The apparatus according to claim 6, characterized in that the through-hole having at least one interruption extends over the entire circumference of the cylindrical roller body.
9. The apparatus according to claim 1, characterized in that the surface of the cylindrical roller body has a plurality of parallel and spaced through-holes.
10. The apparatus according to claim 1, characterized in that the surface of the cylindrical roller body has a sieve structure.
11. The apparatus according to claim 1, characterized in that the sensor is arranged stationary with respect to the direction of movement (X) of the material web.
12. The apparatus according to claim 1, characterized in that the sensor is attached to at least one linear guide that can be adjusted transversely with respect to the direction of movement (X) of the material web.
13. The apparatus according to claim 1, characterized in that the cylindrical roller body is attached at its end face via a thin ring bearing.
14. A method for non-contact thickness measurement of a continuous, particularly flexible, elastic, and / or coated material web, comprising: Guiding the material web, in particular, at least partially onto a cylindrical contact body; Simultaneously detecting the upper surface of the material web by a first sensor and the lower surface of the material web by a second sensor, wherein the detection areas of both sensors are aligned with each other, and the second sensor is at least partially arranged below the contact area between the material web and the contact body; Determining the thickness (t) of the web using the sensor values obtained by the first and second sensors.
15. The method according to claim 14, wherein the material web is deflected by the cylindrical roller body.