EP2206666A1 - Method for registering an error in a strip of material - Google Patents

Abstract

The method involves determining a position of an error (F) on a material web (10). A diameter of a winding of the material web is determined during rolling of the material web to a material roll (16) as a reference value for recognizing the error during unrolling of the material web from the material roll. The determined diameter is electronically stored, and a signal for measuring and storage of time and length of the material web is released by an operating person during occurrence of the error at a monitoring place.

Description

The invention relates to a method for registering a defect on a material web prior to winding the material web into a roll of material and recognizing the defect when unwinding the material web from the roll of material, in which method for determining an error on the material web to be wound at the time of the appearance of the defect used at an observation location wound length of the material web is used.

For current webs, especially in highly sensitive film webs, such. B. single or multi-layer plastic films, optionally in combination with other materials such. As paper or metal foils, different errors may occur, such as material cracks, distortions, refolding and the like. In the printing of such webs moreover can also cause errors due to misprints or the like.

From practice, it is known to insert paper strips at those points of the roll of material at which defects are present when printing on plastic film webs. By inserting paper strips an operator is given an indication that there is a fault at this point. The operator then has the opportunity to take the appropriate measures to ensure that the fault does not cause a fault in a subsequent processing step. The material web can also be rewound in order to separate areas with faulty locations from the material web, so that a faultless material web is available again for a subsequent processing step. Out DE 198 47 466 A1 It is known in such a method to automatically detect the paper strip wrapped in a material web roll with a sensor and to trigger control signals via a signal processing device to automatically shut down or slow down a system when an error occurs, for example. The insertion of paper strips, however, is a cumbersome, time-consuming procedure and is Moreover, associated with an accident risk for the operator when the paper strip is not inserted with a device.

Out DE 20 2004 014 157 A1 a marking device for the marking of defects on moving webs in printing devices is known. The marking device has an automatic or manually remotely controllable application device with an application head for a contact application of a colored liquid on the web.

Although color marking systems allow a precise localization of faulty areas. However, especially with packaging materials strict regulations must be observed in terms of the colors used. In addition, marking on the edge of webs of material is a rather expensive process.

Out WO 99/10833 A1 is a monitoring system for moving material webs known. The system includes a video camera positioned close to the web which provides images of the web surface to an image processing system in real time. Errors can also be detected with the image processing system. The entire web of material is recorded by the video camera, and the images can interactively during recording or for a detailed examination after rewinding z. B. be viewed in slow motion. Video cameras are not well-suited to detecting true imperfections because setting appropriate sensitivity is not easy.

Marking methods that use up to the appearance of a fault wound up or unwound length of the web as a reference for the localization of errors, are poorly for a web processing over several stages, when the web repeatedly wrapped and at each Umwickelvorgang a substantially unknown, under However, considerable length of defective material is cut out of the material web.

The invention has for its object to provide a method of the type mentioned, which allows a simple way and regardless of the length of the wound material web accurate localization of defects.

To the inventive solution of the problem leads to the fact that at the time of the error at the observation point, the diameter of the winding containing the error of the web when winding the web to the roll of material as the comparison value for recognizing the error in unwinding of the web is determined by the roll of material.

In a first embodiment of the method according to the invention, the length of the material web wound up per revolution of the roll of material is measured, and the diameter of the winding of the material web having the defect on the roll of material is calculated therefrom.

Suitably, the length is measured to perform from 1 to 10, for example, about 3 to 6 revolutions and an average value for calculating the diameter determined. When measuring the ideal length of the wound material web and the thickness of the material is taken into account, since z. B. 2 mm of a 20 micron thick material on a large scale more material (running meter) are than 2 mm of a 100 micron thick material.

Upon the appearance of a fault at the point of observation, an operator may trigger a signal to measure and store the time and length of the web wound at n revolutions of the roll of material.

The appearance of a fault at the point of observation can also be detected automatically and trigger a signal to measure and store the time and length of the wound at n revolutions of the material roll web.

The diameters assigned to all faults are preferably stored electronically in a so-called shop floor system (shop floor system) and reused in the next processing step. If a video train monitoring system is installed, an image with the error could also be saved.

In a second embodiment of the method according to the invention, at the time of an error, the radius of the winding containing the fault is measured by measuring the distance between a fixedly mounted and non-contact length measuring sensor and the surface of the wound material web on the roll of material along a measuring beam directed perpendicular to the material web determined.

When an error occurs at the observation location, an operator can trigger a signal to store the distance measured by the length measuring sensor.

The appearance of a fault at the point of observation can also be detected automatically and trigger a signal to store the distance measured by the length measuring sensor.

Fig. 1, 2

das Verfahrensprinzip einer ersten Ausführungsform des erfindungsgemässen Verfahrens;

Fig. 3, 4

das Verfahrensprinzip einer zweiten Ausführungsform des erfindungsgemässen Verfahrens.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing; this shows schematically in

Fig. 1, 2

the method principle of a first embodiment of the inventive method;

Fig. 3, 4

the process principle of a second embodiment of the inventive method.

In the figures, for reasons of a clearer representation in each case Position of the diameter D mentioned in the description of the corresponding radius R drawn. It should be mentioned at this point that, taking into account the relationship 2R = D, radius and diameter are synonymous and thus interchangeable parameters.

In a first embodiment of the inventive method is according to Fig. 1 in a not shown in the drawing, first processing step A, for example, from a first plastic film by extrusion lamination with a second plastic film a sheet-shaped material web 10 - z. B. a packaging film of a thickness of for example 40 microns - prepared and then wound onto a cylindrical winding core 12 to a roll of material 16. The winding core 12 comprises a drive shaft 14, which can be set in rotation by means of a control in the direction of belt travel y via a drive unit, not shown in the drawing.

n

Anzahl Umdrehungen der Materialrolle 16

L_Fn

Länge der Materialbahn 16 für n Umdrehungen der Materialrolle 16 bei Erscheinen eines Fehlers F

U_F

Umfang der Materialrolle 16 bei Erscheinen eines Fehlers F

D_F

Durchmesser der Materialrolle 16 bei Erscheinen eines Fehlers F

Immediately prior to winding, the web 10 is visually inspected by an operator or automatically by means of an error detection system, e.g. B. via a web of material 10 arranged line scan camera 18, examined for faulty locations. As soon as an error F passes an observation point P, the length L _Fn required for n revolutions of the material roll 16 is measured, and from this the location of the error F on the material web 10 as the instantaneous diameter D _{F of} the material roll 16 at the time the error F appears Observation point P calculated as follows: $$\begin{array}{cc}\begin{array}{cc}{\mathrm{L}}_{\mathrm{Fn}}\mathrm{/}\mathrm{n}\mathrm{=}{\mathrm{U}}_{\mathrm{F}}& {\mathrm{U}}_{\mathrm{F}}\end{array}\mathrm{=}{\mathrm{D}}_{\mathrm{F}}\mathrm{\cdot }\mathrm{\pi }& {\mathrm{D}}_{\mathrm{F}}\mathrm{=}{\mathrm{U}}_{\mathrm{F}}\mathrm{/}\mathrm{\Pi }\end{array}$$

n

Number of revolutions of the material roll 16

L _Fn

Length of the material web 16 for n revolutions of the roll of material 16 in the event of an error F

U _F

Scope of the roll of material 16 in the event of an error F

D _F

Diameter of the roll of material 16 in the event of an error F

Depending on the web running speed, the number of revolutions which is ideal for a length measurement is between 1 and about 10, with average web running speeds of about 100 to 200 m / minute between about 3 and 6.

During the winding process, the length L of the wound up or unwound web 10 is registered continuously. When an error occurs, a time t _{1 is} determined for a length L ₁ . After n turns, the length L _{2 is determined} at a time t ₂ . The length L _{Fn of} the material web 10 for n revolutions of the material roll 16 results from L _Fn = L ₂ - L ₁ . The diameter D _F is determined for a mean value (t ₁ + t ₂ ) / 2 with a time measurement of ± 1 second which is sufficiently accurate for later finding of the error F.

For each error F, the associated diameter D _F at the beginning and at the end of the error and the length of the error (running meter) are stored in a computer system.

The triggering of the length measurement when an error occurs can, for. B. by an operator by pressing a button. The length measurement can also be triggered automatically by arranging a corresponding error detection system. In conjunction with a video camera, it is also possible to couple the triggering of the length measurement with an image acquisition, so that the error z. B. can be made visible before the subsequent processing stage.

The finished wound roll of material 16 of Fig. 1 will now according to Fig. 2 unwound and fed to a next processing stage B. In this case, the number n revolutions of the material roll 16 and the length L _{x of} the wound up or unwound web 10 is continuously registered continuously, and from this the actual diameter D _{x of} the material roll 16 corresponding to each length L _{x is} calculated. In this case, a previous removal of the outermost few turns when setting up the material web 10 for further processing in the subsequent processing stage B has no influence on the calculation of the instantaneous Diameter D _x . By comparing D _F with D _x , the error F detected after the processing stage A can be localized with high accuracy when unwinding the material web 10 from the material roll 16 before further processing in the processing stage B with a match D _x = D _F. An operator may at this time either remove the error F before processing stage B, or allow the error F to pass through the processing stage B and, if appropriate, locate and remove it before entering a further processing stage C in the same manner described.

In one of the first embodiment according to the Fig. 1 and 2 corresponding second embodiment of the inventive method is according to Fig. 3 when passing an error F on the material web 10 at the observation point P, the instantaneous diameter D _{F of} the material roll 16 by measuring the distance e _F between a constant distance S to the axis of rotation of the roll of material 16 fixedly mounted and non-contact length measuring sensor 20 and the surface of the wound material web 10 on the roll of material 16 along a direction perpendicular to the surface of the roll of material 10 directed measuring beam M in a simple manner from the difference between the distance S and the distance e _F to R _F = S - e _F determined and stored. With R _F here the instantaneous radius corresponding to the half instantaneous diameter D _F / 2 of the material roll 16 is designated.

When unwinding the roll of material 16 and feeding the web 10 to a next processing stage B is according to Fig. 4 continuously determines the instantaneous diameter D _{x of} the material roll 16. As described above with reference to Fig. 2 2, by comparing R _F with R _x, the error F detected after processing stage A can be located during unwinding of the material web 10 from the material roll 16 before further processing in the processing stage B at the match R _x = R _F. Essential in the direct measurement of the distance e _F or e _x by means of a length measuring sensor 20 is its measuring accuracy in a range of about 20 to 50 microns and the concentricity of the roll of material 16th

Claims (9)

Method for registering a fault (F) on a material web (10) before winding the material web (10) into a roll of material (16) and recognizing the defect (F) during unwinding of the web (10) from the roll of material (16) which method for determining the location of a defect (F) on the material web (10) to be wound up serves the length of the material web (10) wound up at the time of appearance of the defect (F) at an observation location (P),
characterized in that
at the time of the appearance of the fault (F), the diameter (D _F ) of the winding (10) containing the defect (F) during winding of the material web (10) to the material roll (16) as a comparison value for recognizing the defect (F) Unwinding of the material web (10) from the roll of material (16) is determined. Method according to Claim 1, characterized in that the length (L _F ) of the material web (10) wound up per revolution of the material roll (16) is measured and, mathematically, the diameter (D _F ) of the winding of the material web (10) has the defect (F) ) is determined on the roll of material (16). A method according to claim 2, characterized in that the length (L _Fn ) for the execution of 1 to 10, in particular about 3 to 6 revolutions measured and an average value for calculating the diameter (D _F ) is determined. A method according to claim 2 or 3, characterized in that an operator at the appearance of an error (F) at the observation site (P) a signal for measuring and storing the time (t) and the length (L _Fn ) of n revolutions of the roll of material ( 16) wound material web (10) triggers. A method according to claim 2 or 3, characterized in that the appearance of a fault (F) at the observation (P) is automatically detected and a signal for measuring and storing the time (t) and the length (L _Fn) of at n revolutions of the Material roll (16) wound material web (10) triggers. Method according to one of claims 1 to 5, characterized in that the diameters (D _F ) are stored electronically for all errors (F). A method according to claim 1, characterized in that at the time of appearance of a fault (F) the radius (R _F ) of the winding containing the fault (F) by measuring the distance (e _F ) between a fixedly mounted and non-contact length measuring sensor (20 ) and the surface of the wound material web (10) on the roll of material (16) along a perpendicular to the material web (10) directed measuring beam (M) is determined. A method according to claim 7, characterized in that an operator at the appearance of a fault (F) at the observation (P) measured from a signal for storing the length measuring sensor (20) distance (e _F) is triggered. A method according to claim 7, characterized in that the appearance of a fault (F) at the observation location (P) is detected automatically and a signal for storing the distance measuring sensor (20) measured distance (e _F ) triggers.

Images