Method for producing corrugated cardboard web by means of corrugated cardboard installation, corrugated cardboard installation and computer program product

Abstract

The invention relates to a method for producing a corrugated cardboard web (4) by means of a corrugated cardboard installation (2), in which a plurality of paper rollers (10, 12) are provided, each paper roller having a paper web of paper, the paper rollers (10, 12) being each characterized by a plurality of paper parameters (16) having individual values for each of the paper rollers (10, 12), such that the paper rollers (10, 12) have individual values for each of the paper rollers (10, 12). Each of the two paper rollers (10, 12) is individually characterized on the basis of its value for the paper parameter (16), a distribution rule (18) is provided which associates the paper parameter (16) of the two paper rollers (10, 12) with a quality parameter (20) generated in combination of the two paper rollers (10, 12) for producing the corrugated cardboard web (4), a first paper roller (10) and a second paper roller (912) are selected from the paper rollers (10, 12) by means of the distribution rule (18), and the first paper roller (10) and the second paper roller (912) are selected from the paper rollers (10, 12) by means of the distribution rule (18). In order to optimize the quality parameter (20), the corrugated cardboard web (4) is produced by feeding the first and second paper rollers (10, 12) to the corrugated cardboard installation (2), and then the corrugated cardboard installation (2) connects the paper webs of the first and second paper rollers (10, 12) to each other. The invention also relates to a corrugated board device (2) and a computer program product.

Description

Technical Field

[0001] The invention relates to a method for producing a corrugated board web by means of a corrugated board machine, a corresponding corrugated board machine and a computer program product. Background Art

[0002] Corrugated board plants are used to produce corrugated board webs. In this case, the corrugated board plant is loaded with a plurality of paper webs in the form of paper rolls. The paper rolls are unrolled by a corresponding unrolling machine of the corrugated board plant, and the paper webs produced therefrom are connected to one another via several processing units to form a corrugated board web. For example, one of the paper webs (the so-called shaft) is corrugated with a corrugating roll and then glued with two non-corrugated paper webs (e.g. outer layers). Multi-layer corrugated board webs with more than one corrugated web are also possible. The finished corrugated board web is finally optionally assembled by the corrugated board plant, i.e. cut into individual parts and, if necessary, still slit and / or slotted.

[0003] The quality of the produced corrugated board web depends on the one hand on the selection of suitable values ​​for the operating parameters of the corrugated board machine during operation (i.e. during the production of the corrugated board web), but on the other hand also on the properties of the paper web from which the corrugated board web is produced. For example, during the operation of the corrugated board machine, the operating parameters are set manually by an operator or automatically based on measurements using sensors immediately before the respective processing unit (online measurement). In this way, it is possible to react to changing ambient conditions as well as to changing properties of the paper web. For example, temperature and humidity regulation is conceivable for adapting the temperature and humidity of the respective paper web as part of the control of the corrugated board machine in order to influence the processing result of this processing unit as optimally as possible immediately before the respective processing unit.

[0004] Despite efforts to make the webs as similar as possible, the properties of different webs can sometimes differ greatly, so that webs with different properties are often connected to one another. Depending on the properties of the webs and the degree of their differences, the quality of the corrugated board web can be reduced or even directly waste can result. For example, deformations of the corrugated board web (also called "warping") are often due to the different properties of the webs that are connected together. Furthermore, depending on the moisture content of the webs, the webs may not be optimally glued to one another in certain circumstances. In principle, it is conceivable to control the corrugated board plant in such a way that its operating parameters are set in such a way that the varying properties of the webs are compensated as much as possible.

[0005] Reference US11,162,226B2, US10,095,206B2, EP 3 392 649 B1, EP 3 369564B1, EP 2572 038 B1, EP 2 406 616 B1, EP 2 391 505 B1, EP 1 902833A1, EP 0 936 059 A2, DE10 2017 219 064 A1, DE 10 2015 206 650 A1, CN 107 458 032A, CN 107 631 684A, CN112 644 092B, CN 207 105 756U, CN 210 553 357U. Summary of the invention

[0006] In this context, an object of the present invention is to improve the production of corrugated board webs. To this end, a suitable method, a corrugated board apparatus and a computer program product for producing a corrugated board web will be provided.

[0007] According to the invention, this object is achieved by a method having the features of claim 1, a corrugated cardboard machine having the features of claim 14 and a computer program product having the features of claim 15. Advantageous embodiments, improvements and variants are subject matter of the dependent claims. The statements made in connection with the method apply equally to the corrugated cardboard machine and the computer program product and vice versa. If the steps of the method are given below, an advantageous design of the corrugated cardboard machine is that it is designed to carry out one or more of these steps (in particular with the aid of a control unit of the corrugated cardboard machine). Similarly, an advantageous design of the computer program product is that it comprises commands which, when executed by the corrugated cardboard machine, cause the corrugated cardboard machine to carry out one or more of these steps.

[0008] The method is used to manufacture a corrugated board web by a corrugated board machine. First, a plurality of paper rolls are provided, each paper roll having a paper web. The paper rolls are arranged in particular in roll bearings, from which the paper rolls are supplied to the corrugated board machine as required and, if necessary, replenished by supplying new paper rolls. The roll bearings are usually located near the corrugated board machine.

[0009] The paper rolls are each characterized by a plurality of paper parameters having individual values ​​for each of the paper rolls, such that each of the paper rolls is individually characterized based on its values ​​for the paper parameters. The term "plurality" is to be understood here and more generally as "one or more" or "at least one". The paper parameters of an individual paper roll and their values ​​are also referred to as "paper data", which together form a data set for the paper roll.

[0010] The core idea of ​​the invention is in particular that among the several paper rolls (which can be used to produce a corrugated board web), those which, due to their paper parameters, lead to the best possible production result, i.e., a corrugated board web of the highest possible quality, are precisely combined with one another during the production of the corrugated board web. This process is also referred to as "role matching" or "role pairing" for short. In this respect, the method described here is also a method for selecting paper rolls for producing a corrugated board web. The paper rolls are therefore not combined arbitrarily, but are selected and combined intelligently based on paper parameters. The selection, preferably the entire method, is particularly automatic. With the help of paper data, different paper rolls are combined in a smart way, thereby optimizing the production of the corrugated board web. In this way, an intelligent "role matching" is achieved, in which two paper rolls are combined with one another while taking their paper data into account. Instead of an arbitrary supply of paper rolls, the paper roll supplied at a given point in time is selected according to its degree of matching with other paper rolls that have just been supplied or have already been processed.

[0011] In this case, an assignment rule is provided, which associates the paper parameters of two (i.e. at least two) paper rolls with the quality parameters for manufacturing a corrugated board web produced at the combination of the two paper rolls. The quality parameter thus indicates the degree to which the two paper rolls cooperate with each other and is in particular also directly or indirectly a measure of the quality of the corrugated board web, which can be achieved by the combination of these paper rolls. The assignment rule thus serves to evaluate a specific combination of two paper rolls, thereby allowing an optimized selection. In the following, for the sake of simplicity and without limiting the generality, it is assumed that only two paper rolls are combined with each other, but these statements apply equally to combinations of more than two paper rolls. Thus, the assignment rule assigns a quality parameter to the corresponding combination of paper parameters, more precisely: its value, more precisely: the value of the quality parameter. For different combinations of paper rolls, the quality parameter changes regularly, but not mandatory. The details of the assignment rule are initially secondary; initially it is only important that the assignment rule associates a specific combination of paper rolls with a quality parameter based on the paper parameters of the paper rolls. This is achieved, for example, by a suitable calculation model and / or on the basis of historical data.

[0012] In a suitable embodiment, the allocation rule is semi-learned, that is, it is generated in advance in a machine learning method, in particular, in which the quality parameter is measured as a function of the paper parameter. The allocation rule is then derived from this function. Different methods are suitable for the learning process; in this case, the details are initially unimportant. Knowledge of the causal or cause-effect relationships is not necessarily important, but it is basically sufficient to predetermine the allocation rule empirically by suitable experiments, learning methods and / or big data methods. In this regard, the allocation rule itself is also not necessarily known, but is in particular a black box that only outputs the corresponding value of the quality parameter for the given paper data (or for the paper data of the first paper roll combined with the quality parameter and then outputs the paper data of the best second paper roll). For example, the allocation rule is implemented by a neural network or the like, for example in a virtual sensor of a corrugated board machine. In principle, various solutions that achieve similar or identical results in different ways are conceivable and suitable.

[0013] Within the framework of the method, a first paper roll and a second paper roll are selected from the paper rolls in such a way that the quality parameter is optimized by means of an allocation rule. The combination of the first and second paper roll is also referred to as a "roller pair" (if there are more than two rolls, a "roller tuple"). How exactly the quality parameter is optimized is initially secondary and depends to a large extent on the quality parameter actually used. The term "optimize" is preferably understood to mean "minimize", "maximize" or "get as close as possible to a set value".

[0014] In principle, various procedures are possible and advantageous in each case when selecting the paper rollers. In a first embodiment, the first paper roller is selected arbitrarily or predetermined in another way, for example, the first paper roller is already contained in the corrugated board machine. In this case, the second paper roller is then selected, for example by determining the quality parameters for each combination of the first paper roller with the remaining available paper rollers using an allocation rule, and then selecting the corresponding best combination. Alternatively, the entire roller pair, i.e. the first paper roller, is selected by optimization, i.e. the best roller pair is selected from all available paper rollers. For example, the quality parameters of all possible roller pairs are determined by an allocation rule, and then the roller pair with the highest quality parameters is used.

[0015] In order to enable a selection, at least two paper rollers are expediently provided as possible second paper rollers.

[0016] In this case, without limiting the generality, it is assumed that the paper parameters of the actually existing paper roll are provided to the allocation rules in order to then determine the optimization parameters. This is also referred to as the "best available result" method. An equivalent variation to this is to use the allocation rules to determine the optimal paper data for the second paper roll from the paper data of the first paper roll and predetermined optimization parameters, and then select from the existing paper rolls the paper roll whose paper data is closest to the optimal paper data as the second paper roll. This is also referred to as the "best available match" method. In both cases, the optimization parameters are optimized.

[0017] Finally, within the framework of the method, a corrugated board web is produced by supplying a first and a second paper roll to a corrugating board machine, which then connects the paper webs of the first and second paper rolls to one another. In other words, the corrugating board machine is loaded with two paper rolls, which then produce a corrugated board web from their paper webs, if necessary in combination with other paper webs of other paper rolls. Thus, the paper webs of the first and second paper rolls are either directly connected together or indirectly connected via one or more additional paper webs. The first and second paper rolls are supplied to the corrugating board machine simultaneously or in a chronological sequence. It should be emphasized that the paper webs of the first and second paper rolls are also connected to one another, because only in this case do the two paper webs interact in such a way that it is relevant and advantageous to consider their paper parameters.

[0018] In particular, a plurality of paper rolls are supplied to the corrugated board machine in two ways. On the one hand, a plurality of paper rolls are supplied to the corrugated board web, the paper webs of which are connected to one another as different layers of the corrugated board web, that is, a plurality of paper rolls for different layers are supplied more or less simultaneously. On the other hand, a plurality of paper rolls are also supplied to the corrugated board web in a chronological order in succession to achieve a continuous operation. For the method described here, the paper webs of the first and second paper rolls preferably form different layers (e.g. fluting, front / rear covering layers, etc.) of the corrugated board web. Without limiting the generality, this will be assumed in the following. However, the invention described here is also advantageous in principle if the two paper webs form the same layer. This usually occurs during splicing, i.e. when the first paper roll is almost used up, and then the second paper roll is spliced ​​with the first paper roll at the end to ensure the continuous operation of the corrugated board machine. This produces a splicing point where the two paper rolls are connected to one another and, if necessary, this splicing point benefits from the optimization described here.

[0019] The corrugated board machine has a number of adjustable operating parameters with the help of which the behavior of one or more processing units of the corrugated board machine is controlled. Examples of processing units are unrollers, splicers, printers, single facers, bridges, preheaters, gluing units, double facers, drying sections, cutting units, slitting units, slotting units, etc. However, the details of the processing units are not important in this case. Examples of operating parameters include: conveying speed, tensile stress, ink amount, corrugating roller temperature, glue amount, water amount for wetting, drying temperature, slitting and / or slotting positions, etc. The details of the processing parameters are also not important in this case.

[0020] The respective paper roll is formed in particular of a paper web and a sleeve (also called a bushing) on ​​which the paper web is rolled up, which is unwound from a corrugated board machine for producing the corrugated board web by means of an unwinder and which is suitably connected to other paper webs of other paper rolls. The respective paper web is made of paper or consists of paper.

[0021] As mentioned above, paper rolls are in each case characterized by a plurality of paper parameters. More precisely, the paper of the respective paper roll is characterized by these paper parameters. Thus, the paper parameters specifically characterize the paper of the respective paper roll, however, in this case, for the sake of simplicity, only the paper roll is occasionally mentioned, however, in this case, specifically its paper is referred to. The paper parameters respectively describe one or more properties of the paper of the paper roll indirectly or directly, so that different values ​​respectively represent or imply different properties. The term "paper parameter" here is particularly broad and refers not only to the physical, mechanical or chemical properties of the paper itself, but also to any information that can characterize the paper, such as the place of manufacture of the paper, the time of manufacture, the storage time or the operating parameters of the paper machine during the paper manufacturing process. In a suitable design, the paper data are average values ​​or spatially and / or time-resolved values ​​(e.g. spatially resolved humidity along the length and width of the paper web) or a combination thereof. For example, the paper parameter is the fiber orientation of the paper in the paper roll, and the associated value for the first paper roll is a, for the second paper roll is b and for the third paper roll is c.

[0022] The values ​​of the paper parameters are thus individual for each paper roll (more precisely: its paper), which does not, however, exclude that two paper rolls do not have the same value for a particular paper parameter. However, often, due to its manufacture, storage, transport, etc., the paper of two paper rolls differs in one or more paper parameters and therefore has different properties, which influence the processing in the corrugated board plant. In this case, this individuality of the paper rolls is taken into account and used in the production of the corrugated board web in order to optimize the production of the corrugated board web by a clever combination of paper rolls. In this case, the paper data are not or not completely determined only in the corrugated board plant, but are determined before the corrugated board plant, in particular outside and independently of the corrugated board plant. The paper data advantageously contain the history and / or previous life of the paper of the paper roll, so that the paper data represent, so to speak, the resume of the paper roll. In particular, the paper data do not necessarily contain only paper parameters that can also be determined online in the corrugated board plant, but advantageously also paper parameters that in principle cannot be determined at all in the corrugated board plant, such as papermaking process parameters. The method proposed here is therefore correspondingly dynamic, since the individual characteristics of the paper roll are taken into account. The paper parameters themselves, and therefore the paper data as a whole, are either static, i.e. constant for the paper of the entire paper roll, or dynamic, i.e. varying along the paper roll, so that, for example, a parameter curve is generated depending on the corresponding just unrolled section of the paper web. Combinations are also possible, so that one or more paper parameters are static, and one or more other paper parameters are dynamic.

[0023] Typically, up to now, no particular coordination between the paper rolls has been provided. This itself was not originally necessary either, since for the corrugated board layer, a feedback control is in principle possible, in which any errors and inaccuracies caused by the paper rolls in combination with the changing paper parameters are reacted on the basis of the manufactured corrugated board web by readjusting. However, readjustment is not necessarily possible in all cases. Moreover, readjustment often leads to the manufacture of waste or at least a non-optimal product in the meantime, which reduces the economic viability of the corrugated board plant. In contrast, the method proposed here allows the predictive selection of the best paper roll in each case, i.e. the paper roll that leads to the best result, so that the need for readjustment is particularly small. Since the paper rolls are intelligently combined, the controlled system for readjustment is released accordingly.

[0024] Preferably, the usage values ​​of the paper parameters of the individual paper rolls are as aggregated as possible, i.e. received by the corrugator from as few different sources as possible, and preferably only from a single source, and thus as a data set that is as combined as possible. Thus, the paper data are preferably not transmitted to the corrugator at different locations and / or at different times, but rather are collected in a single data set and / or at a single time. Optionally, even the paper data of a plurality of paper rolls are aggregated in a similar manner, i.e. individual values ​​can still be assigned to the individual paper rolls, conveniently with the aid of the ID of the respective paper roll.

[0025] The invention makes use in particular of the fact that the properties of the paper of the respective paper roll are also taken into account individually in order to select, starting from a first paper roll with given properties, the best matching second paper roll and then to manufacture a corrugated board web with the highest quality. A further advantage is therefore that paper rolls with greater tolerances can also be used, since any deviations from the ideal values ​​defined as paper parameters can now be optimally compensated by a clever combination with a suitably matched second paper roll. As a result, paper and paper rolls in general can be manufactured more easily and more economically. Furthermore, paper rolls which were previously discarded due to too great defects can now also be used.

[0026] Optimization of production can be achieved in various ways. Suitably, the production of the corrugated board web is optimized with the aim of improving the properties of the corrugated board web (corrugated board properties) or of improving the operation, in particular the control, of the corrugated board plant. Accordingly, in a first suitable embodiment, the quality parameter is a corrugated board parameter describing the properties of the corrugated board web or depends on such a corrugated board parameter (e.g. it is also advantageous to combine several corrugated board parameters into a single quality parameter). Suitable corrugated board parameters are in particular the degree of curvature of the corrugated board web, also called "warp", strength values ​​of the corrugated board web, in particular the resistance to edge compression (e.g. according to ECT=edge crush test), the resistance to flat compression (e.g. according to FCT=flat crush test), etc., and generally any corrugated board property.

[0027] Alternatively or additionally, the quality parameter is a variation (e.g. a control range or interval) of an operating parameter of the corrugator during the production of the corrugated board web, or depends on such a variation (e.g. a combination of several variations to form a single quality parameter is also advantageous). This is based on the consideration that the corrugator has a certain margin in terms of operating parameters, and then it is convenient to select and combine paper rolls so that only the smallest possible margin is required. In other words, the variations are minimized. Then, the corrugator requires particularly few readjustments during operation.

[0028] In an advantageous embodiment, the allocation rule is designed and the quality parameter is selected in such a way that the latter is optimized by such a combination of paper rollers with paper parameters that compensate for one another. The type of compensation depends in particular on the paper parameter. "Compensation" means in particular that the two values ​​of the paper parameter of the two paper rollers have the same absolute value but opposite signs, or that the distance between the values ​​is in each case equal to a set value, or that the difference between the two values ​​does not exceed a maximum difference. In the case of paper parameters that specify orientations or angles (e.g. fiber orientation), "compensation" means in particular that the orientations are perpendicular to one another.

[0029] In a preferred embodiment, one of the paper parameters of the respective paper roll is the humidity (dynamic or static) and the quality parameter is a measure of the humidity difference (difference), i.e. the quality parameter indicates how much the humidity of two paper rolls processed simultaneously differs. For example, the quality parameter is directly the difference or ratio of the humidity of the two paper rolls. Alternatively, the quality parameter is a parameter that depends on it, such as the so-called warp (curvature or bend) of the corrugated board web produced from the paper roll. The allocation rule links the humidity accordingly, for example, subtracts the humidity from each other. The quality parameter is then optimized, for example by minimizing it in the case of a difference or at least not exceeding a predetermined maximum value.

[0030] Advantageously, during or after the manufacture of the corrugated board web, the quality parameters of the respective combination of two paper rolls are repeatedly measured and the paper parameters of the two paper rolls are stored in a database together with the quality parameters as historical data. The allocation rules are then appropriately based on the historical data. In this way, an automated "role matching" based on experience is achieved. As described above, this use of historical data is also applicable to learning allocation rules. A simple comparison with historical data is also useful, for example, for a given first paper roll, the paper roll that is most similar to the first paper roll in terms of paper parameters is searched in the historical data. In the historical data, the second paper roll is assigned to the second paper roll with paper parameters that optimize the quality parameters. Therefore, now find a roll among the remaining paper rolls that is most similar to the second paper roll in history and then select it.

[0031] Which paper parameters are used specifically is initially secondary, and as the number of paper parameters increases, the relevance becomes less important. Therefore, it is preferred to use at least 10 paper parameters, in particular at least 100. The total amount of paper data is mainly generated by the number of values ​​stored for the respective paper parameters. Static paper parameters contain only a single value (e.g. a flow meter on a paper roll, a production date or an average value of a dynamic paper parameter, an average humidity), while dynamic paper parameters contain multiple values ​​(e.g. humidity as a function of the width and length of the paper roll), which depends in particular on the value density / sampling rate (e.g. 1 / cm) and is usually in the range of 1,000 to 1,000,000 or more. Paper parameters also do not necessarily have a directly identifiable causal relationship with the quality parameters. In particular in the aforementioned big data methods, the knowledge of the relationship is secondary. However, some paper parameters generally have a greater influence on the quality of the corrugated board web than other paper parameters and are therefore preferably used, in particular when only a few (i.e. a maximum of 10) or only a single paper parameter is used. Therefore, in a suitable design, the one or more paper parameters are selected from the following paper parameters: fiber orientation of the paper of the paper roll, failure stress of the paper of the paper roll.

[0032] In a suitable design, at least one paper parameter is a dynamic paper parameter, the value of which is specified as a function of the width and / or length of the paper web of the paper roll. In contrast, static paper parameters have the same value along the entire paper web. Suitable dynamic paper parameters are: fiber orientation as a function of the width and / or length of the paper web, temperature as a function of the width and / or length of the paper web, for example in the form of a "heat map", which indicates the temperature at corresponding locations of the paper web, and humidity as a function of the width and / or length of the paper web, similar to, for example, in the form of a "humidity map". Dynamic paper parameters differ in that they have potentially different values ​​at different points in the paper web and thus describe the inhomogeneities of the paper roll. By using one or more dynamic paper parameters, a more detailed image of the paper roll is obtained, which image is advantageously used to combine paper rolls for optimization.

[0033] Papermaking process parameters, i.e. process parameters used in the papermaking process of the respective paper roll itself, are also suitable as paper parameters. Papermaking process parameters are not direct, immediate properties of paper (such as moisture, fiber orientation, length, width, etc.), but are parameters of paper manufacturing and are therefore only indirect or indirect paper parameters. In a suitable design, the paper parameters accordingly include a plurality of papermaking process parameters used in the manufacture of the paper roll. Papermaking process parameters are in particular operating parameters of a paper machine used to manufacture the paper roll and / or the paper used to manufacture the paper roll. With papermaking process parameters, correlations are conveniently determined between the manufacture of corrugated board and the manufacture of the paper used, which cannot be identified in direct paper parameters in some cases. Therefore, in some cases, it is not necessary to subsequently determine other paper parameters, such as failure stress and fiber orientation, temperature, humidity, etc., and these parameters are therefore completely or partially omitted in an advantageous design. In this case, use is made of the knowledge that the manufacture of the paper roll ultimately significantly affects its properties, and that the manufacture in turn significantly affects the papermaking process parameters. Therefore, these are advantageously used directly in the selection and combination of the paper roll.

[0034] Suitable paper parameters are specifically listed below:

[0035] a) Paper Roll Characteristics

[0036] - (precise) sleeve outer diameter

[0037] - (accurate) flow meter on the paper roll

[0038] -Splicing points in paper rolls

[0039] b) History of Paper

[0040] - Date of production

[0041] - Manufacturer name

[0042] - Manufacturing location

[0043] - Date of manufacture

[0044] - Storage time

[0045] - Storage conditions (e.g. ambient humidity and / or temperature)

[0046] -Transportation time

[0047] - Transportation conditions (e.g. ambient humidity and / or temperature)

[0048] c) Basic properties of paper

[0049] -Humidity / moisture content

[0050] - Area quality

[0051] -thickness

[0052] -Ash content

[0053] -Fiber orientation (also called fiber orientation angle)

[0054] d) Tensile properties of paper

[0055] - Breaking force

[0056] -Tear length

[0057] - Elongation at break

[0058] -Modulus of elasticity

[0059] e) Surface / printing properties of paper

[0060] - Smoothness, e.g. according to Bekk

[0061] - Roughness, e.g. according to Bendtsen

[0062] - Breathability, e.g. according to Bendtsen / Gurley

[0063] f) Characteristics of corrugated board (especially the characteristics of corrugated board base paper)

[0064] - Flat compression resistance (e.g. according to CMT = Concora Medium Test, FCT = Flat Crush Test, etc.)

[0065] - Strip compression resistance (e.g. according to SCT = Short Crush Test)

[0066] The above list lists preferred paper parameters, but is not final. It may already be advantageous to use only a subset (optionally only one) of the paper parameters.

[0067] Regardless of whether the paper parameters are static or dynamic, paper parameters are particularly suitable which vary minimally or not at all during the service life of the paper roll, ie until it is processed in a corrugated board plant.

[0068] Suitably, the values ​​of the paper parameters of the respective paper roll are already determined during its manufacture, in particular in the case of the above-mentioned papermaking process parameters. Alternatively or additionally, the values ​​of the paper parameters of the respective paper roll are determined after manufacture, in particular by laboratory tests. In general, it is advantageous if at least some of the paper parameters are already determined during or immediately after manufacture, in particular still by the manufacturer of the paper roll itself, and are suitably stored, for example on a data carrier, for later transfer to the corrugator.

[0069] The corrugated board machine advantageously has a data interface via which the paper parameter values ​​of the paper of the respective paper roll are transmitted to the corrugated board machine. In the sense of the preferred proactive approach here, all values ​​are preferably transmitted together as a single aggregate data set via the data interface and are then immediately available, i.e. the corrugated board machine can access the paper data while the paper roll is for example still stored in the roll bearing, or even earlier. The corrugated board machine is suitably connected to the roll bearing via the data interface.

[0070] In a particularly preferred embodiment, a data carrier is assigned to each paper roll, on which a single value of the paper parameter of the paper of the corresponding paper roll is stored. Thus, the corresponding data carrier is precisely assigned to one paper roll and contains in particular only the paper data of a single paper roll. Preferably, the data carrier for the method described here is read from a corrugated cardboard machine. For this purpose, the corrugated cardboard machine has a suitable reader. The reader is in particular part of the data interface already mentioned. The data carrier is suitably a code, such as a QR code or a barcode, a transponder, such as an RFID tag or an NFC tag, or a volatile or non-volatile memory, such as a floppy disk, a CD or a flash memory. Accordingly, the reader is, for example, a scanner, a receiving unit with an antenna, a drive, a USB port, etc. The data carrier enables an offline solution, in which the values ​​of the paper parameters are transmitted to the corrugated cardboard machine, and the corrugated cardboard machine does not have to be connected to the Internet or other networks to receive the data set about the corresponding paper roll.

[0071] The data carrier is either attached to the paper roll or provided separately from the paper roll. According to one embodiment, the data carrier is a label or a data sheet for the paper roll and is also referred to as a "roll label". Furthermore, the data carrier can advantageously be transported together with the paper roll. Therefore, in an advantageous design, the data carrier is connected to the paper roll, for example directly to its paper web or to the packaging of the paper roll, for example directly glued or printed on the paper or sleeve. As a result, the distribution and handling of the data set are particularly simple. For example, the data carrier is a code that is attached to the paper roll and, when conveyed into the roller bearing, is read by a reader.

[0072] In principle, it is conceivable that a paper roll is used several times (for example three times), that is, after being supplied to the corrugated board machine, it is not necessarily used completely, but only partially used, and then removed from the corrugated board machine and stored again. If necessary, the now partially used paper roll is supplied to the corrugated board machine again at a later point in time. Therefore, the data carrier is preferably designed in such a way that it is reliably connected to the paper roll even in the case where the paper roll is supplied to and removed from the corrugated board machine several times. In a suitable design, for this purpose, the data carrier is detachable and is removed during the supply of the paper roll and is reattached to the paper roll during removal and subsequent storage. In another suitable design, the data carrier is attached to the paper roll in such a way that the data carrier does not need to be removed, i.e. remains on the paper roll when the paper roll is processed in the corrugated board machine. For this purpose, the data carrier is conveniently attached to the center of the paper roll, in particular on or in the sleeve of the paper roll. Contactless or electronically readable data carriers, such as RFID and NFC tags, etc., are particularly suitable for this purpose. Overall, this ensures that the paper parameters are available throughout its entire service life, even in the case of repeated use of the paper roll. What has been said about the data carrier applies analogously to the already mentioned ID, which will be described in more detail below.

[0073] In particular in the case of paper rolls that are reused, the updating of paper parameters is advantageous. To this end, in a suitable embodiment, if the paper roll is removed from the corrugating machine when it is only partially consumed and temporarily stored for later reuse, in particular away from the corrugating machine, for example in a roll bearing, one or more paper parameters of the paper roll are updated. An update is a change to an existing paper parameter or an addition of a new paper parameter. For example, it is convenient to update the length of the paper, i.e. to store the remaining length of the paper or the diameter of the paper roll, as well as essentially all properties of the paper roll that change due to processing in the corrugating machine. Suitable newly added paper parameters are, for example, the unwinding direction, i.e. the direction in which the paper roll is unwound during processing (in particular in the case of fluted paper for the manufacture of corrugated board webs). A particularly advantageous embodiment is one in which one or more operating parameters of the corrugating machine used in the processing of the paper roll are stored during the updating of the paper roll, so that when the paper roll is reused, the operating parameters last used for the paper roll can be immediately accessed and used. Once the operating parameters are selected, they are inherited, so to speak. Alternatively or additionally, during the updating, it is stored with which other paper rolls the paper roll was processed and optionally under which operating parameters the paper roll was processed. In this way, the operating parameters are advantageously learned, which is particularly advantageous in the interaction with this or similar paper rolls (e.g. from the same batch). The updating is performed in particular with a writer of the corrugated board machine. Optionally, the reader and the writer are combined into a writer and a reader.

[0074] As an alternative or supplement to the offline solutions described, online solutions are also advantageous in principle, such as cloud solutions. Such online solutions have the advantage, in particular, that the paper parameters can be determined, for example, by laboratory tests in parallel (i.e. simultaneously) with the transport of the paper rolls, and then the paper parameters are transmitted online. In a suitable design for this purpose, at least one subset (one or more), in particular each, of the paper rolls has a particularly individual ID (also referred to as an identifier or identification mark), which is stored together with the paper data of the corresponding paper roll in a database (the same as the above database or separate), such as a data lake. In a suitable design, the database is part of the cloud. With the help of the ID, it is achieved that a specific paper roll is assigned its paper data, which is then determined and / or stored independently of the paper roll. The paper parameters appropriately reach the database and / or the corrugated board machine via a data interface, but the data interface is not necessarily connected to the roller bearing, but to a suitable network. The use of IDs to assign paper rolls to a set of multiple aggregated data sets has been outlined above. In a suitable design, the database is designed separately from the corrugated board machine and is connected to the corrugated board machine for data transmission, for example via the Internet or via another network. A design in which the database is part of a corrugated board machine is also suitable. The database is either connected only to a single corrugated board machine or, alternatively, to a plurality of corrugated board machines. The corrugated board machine requests the paper data of the respective paper roll from the database based on the ID of the respective paper roll. In principle, it is also advantageous that the assignment rules are also stored in the database and when the corrugated board machine requests a given ID for a first paper roll, the database then directly outputs the ID of the second paper roll that best matches. The ID is advantageously attached to the paper roll, so that the statements about the already mentioned data carrier also apply analogously to the ID.

[0075] The corrugated board machine according to the invention has a control unit which is designed to carry out the method as described above. In particular, the control unit is designed to carry out one or more of the described steps of the method. To this end, the control unit in particular has the database and / or is connected to the database. The control unit conveniently contains the allocation rules.

[0076] Suitably, the corrugated board machine has an order planning system. Using the order planning system, the selection, combination and supply of paper rolls from the roll bearings can be planned in advance. The order planning system in particular interrogates the paper data of the corresponding first paper roll, for example by means of a reader or by means of an ID, and transmits the paper data to the control unit, which then determines the best second paper roll for combination with the first paper roll by means of an allocation rule.

[0077] The computer program product according to the invention comprises commands which, when executed by a corrugated board machine, in particular as described above, cause the corrugated board machine to select a second paper roll from a plurality of paper rolls (minus the first paper roll) using an allocation rule in the method as described above to optimize the quality parameter. In particular, the allocation rule for allocating the two paper rolls to each other is implemented by the computer program product. Suitably, the computer program product also comprises commands which, when executed by the corrugated board machine, implement the order planning system described. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Hereinafter, embodiments of the present invention are explained in more detail based on the accompanying drawings. Figure 1 A corrugated board machine and roller bearings are shown schematically. DETAILED DESCRIPTION

[0079] Figure 1 A corrugated board machine 2 for manufacturing a corrugated board web 4 is shown. The corrugated board machine 2 has a plurality of adjustable operating parameters. The term "plurality" is understood here and more generally as "one or more" or "at least one". The operating parameters are used to control the behavior of one or more processing units 6 of the corrugated board machine 2. Examples of processing units 6 are an unwinder 8, a splicer, a printer, a single facer, a bridge, a preheater, a gluing unit, a double facer, a drying section, a cutting unit, a slitting unit, a slotting unit, etc.

[0080] In the method for manufacturing a corrugated board web 4, several paper rolls 10, 12 are provided, each with a paper web. The paper rolls 10, 12 are arranged in roll bearings 14, from which the paper rolls 10, 12 are supplied to the corrugating board machine 2 as required and, if necessary, the roll bearings 14 are replenished by supplying new paper rolls 10, 12. The roll bearings 14 are usually located spatially close to the corrugating board machine 2.

[0081] The paper rolls 10, 12 are each characterized by a plurality of paper parameters 16, which have individual values ​​for each paper roll 10, 12, so that each paper roll 10, 12 is individually characterized based on its values ​​for the paper parameters 16. The paper parameters 16 and their values ​​associated with an individual paper roll 10, 12 are also referred to as "paper data" and together form a data set associated with this paper roll 10, 12.

[0082] Furthermore, an assignment rule 18 is provided, which associates the paper parameters 16 of two (i.e. at least two) paper rolls 10, 12 with a quality parameter 20 for producing a corrugated board web 4 in the case of a combination of these two paper rolls 10, 12. The quality parameter 20 thus indicates how well the two paper rolls 10, 12 fit each other. In the following, for the sake of simplicity and without limiting generality, it is assumed that only two paper rolls 10, 12 are combined with each other, but these statements also apply analogously to combinations of more than two paper rolls 10, 12. For different combinations of paper rolls 10, 12, the quality parameter 20 changes regularly, but this is not mandatory.

[0083] For example, the allocation rule 18 is semi-learned, that is, it is generated in advance in a machine learning method, in particular, in which the quality parameter 20 is measured as a function of the paper parameter 16. The allocation rule 18 is then derived from this function. The allocation rule 18 itself is not necessarily known, but is in particular a black box, which only outputs the corresponding value of the quality parameter 20 for a given paper parameter 16 (or for the paper parameter 16 of the first paper roll 10, then outputs the paper parameter 16 of the optimal second paper roll 12 in combination with the quality parameter 20). For example, the allocation rule 18 is implemented by a neural network or the like.

[0084] With the aid of the allocation rule 18, a first paper roller 10 and a second paper roller 12 are selected from the paper rollers 10, 12 such that the quality parameter 20 is optimized. The combination of the first and second paper rollers 10, 12 is also referred to as a "roller pair". In one possible design, the first paper roller 10 is randomly selected or otherwise predetermined, for example, the first paper roller 10 has already been received in the corrugated board machine 2. In this case, the second paper roller 12 is then selected, for example, by determining the quality parameter 20 for each combination of the first paper roller 10 with the remaining available paper rollers 10, 12 in the roller bearing 14 using the allocation rule 18, and then selecting the corresponding best combination. Alternatively, the entire roller pair, i.e. the first paper roller 10, is selected by optimization, i.e. the best roller pair is selected from all available paper rollers 10, 12. For example, the quality parameter 20 is determined for all possible roller pairs using the allocation rule 18, and then the roller pair with the highest quality parameter 20 is used.

[0085] In this case, without limiting the generality, it is assumed that the paper parameters 16 of the actually existing paper rolls 10, 12 are supplied to the allocation rules 18 in order to then determine the optimization parameters 20. This is also referred to as the "best available result" method. A variant equivalent to this is to determine the optimal paper parameters 16 of the second paper roll 12 from the paper parameters 16 of the first paper roll 10 and the predetermined optimization parameters 20 with the aid of the allocation rules 18, and then to select the paper roll 12 whose paper parameters 16 are closest to the optimal paper data 16 from the existing paper rolls 10, 12 as the second paper roll 12. This is also referred to as the "best available match" method.

[0086] Finally, the corrugated board web 4 is manufactured by feeding the first and second paper rolls 10, 12 to the corrugator machine 2, which then connects the paper webs of these first and second paper rolls 10, 12 to each other and, if necessary, to other paper webs of other paper rolls 10, 12. The first and second paper rolls 10, 12 are fed to the corrugator machine 2 simultaneously or in a time sequence.

[0087] In the embodiment shown, the paper webs of the first and second paper rolls 10, 12 form different layers of the corrugated board web 4. However, the statements made here also apply if the two paper webs form the same layer. This usually occurs during splicing, i.e. when the first paper roll 10 is almost used up and the second paper roll 12 is then spliced ​​with the first paper roll 10 at the end to ensure continuous operation of the corrugated board machine 2.

[0088] In this case, the respective paper roll 10, 12 is formed by a paper web and a sleeve (also called a liner), on which the paper web is rolled up, which is unrolled from a corrugated board machine 2 for manufacturing a corrugated board web 4 by means of an unwinder 8 and appropriately connected to the other paper webs of the other paper rolls 10, 12.

[0089] The values ​​of the paper parameters 16 are individual for each paper roll 10, 12 (more precisely: its paper), which does not, however, exclude that the two paper rolls 10, 12 also do not have the same value for a particular paper parameter 16. However, usually, due to their manufacture, storage, transport, etc., the paper of the two paper rolls 10, 12 differs in one or more paper parameters 16 and therefore has different properties, which influence the processing in the corrugated board machine 2. In this case, such individualities of the paper rolls 10, 12 are taken into account and utilized in order to optimize the production of the corrugated board web 4 by a clever combination of the paper rolls 10, 12. For example, the paper data contain the history and / or previous life of the paper of the paper rolls 10, 12, so that the paper data can be said to represent the resume of the paper rolls 10, 12. The paper parameters 16 themselves and therefore the paper data as a whole are either static, i.e. constant for the paper of the entire paper roll 10, 12, or dynamic, i.e. varying along the paper of the paper roll 10, 12, so that, for example, a parameter curve is obtained depending on the respectively just unrolled portion of the paper web. Combinations are also possible, such that one or more paper parameters 16 are static, while one or more other paper parameters 16 are dynamic.

[0090] Optimization of production can be achieved in various ways. For example, the production of the corrugated board web 4 is optimized with the aim of improving the properties of the corrugated board web 4 (corrugated board properties), or of improving the operation, in particular the control, of the corrugated board machine 2. In the first case, the quality parameter 20 is, for example, a corrugated board parameter describing the properties of the corrugated board web 4, or depends on such a corrugated board parameter. Suitable corrugated board parameters are the degree of curvature of the corrugated board web 4, also called "warp", strength values ​​of the corrugated board web 4, in particular the resistance to edge compression (for example according to ECT=Edge Crush Test), the resistance to flat compression (for example according to FCT=Flat Crush Test), etc., and in general any corrugated board property. Alternatively or additionally, the quality parameter 20 is a change (for example a control range or interval) of an operating parameter of the corrugated board machine 2 during the production of the corrugated board web 4, or depends on such a change.

[0091] In one possible embodiment, the allocation rule 18 is designed and the quality parameter 20 is selected in such a way that the latter is optimized by the combination of paper rolls 10, 12 with mutually compensating paper parameters 16. The type of compensation depends in particular on the paper parameters 16.

[0092] exist Figure 1 In an embodiment of the invention, during or after the production of the corrugated board web 4, the quality parameters 20 of the respective combinations of the two paper rolls 10, 12 are repeatedly measured, here using a sensor 24, and the paper data of the two paper rolls 10, 12 are stored together with the quality parameters 20 as historical data in a database 26. The assignment rule 18 is then optionally based on the historical data. In this way, an automated "role matching" based on experience is achieved. This use of historical data is also suitable for learning the assignment rule 18. A simple comparison with historical data is also advantageous, for example, for a given first paper roll 10, the paper roll 10, 12 that is most similar to the first paper roll 10 in terms of paper parameters 16 is searched in the historical data. In the historical data, the second paper roll 12 with the paper parameters 16 that optimize the quality parameters 20 is assigned to it. Therefore, the paper roll that is most similar to the second paper roll 12 in history is now searched among the remaining paper rolls 10, 12, and then selected.

[0093] Which paper parameters 16 are used specifically is initially of secondary importance and also becomes less relevant as the number of paper parameters 16 increases. For example, at least 10 paper parameters 16 are used. The total amount of paper data results primarily from the number of values ​​stored in the individual paper parameters 16. Static paper parameters 16 contain only a single value (e.g. a flow meter on the paper roll 10, 12, production date or average value of dynamic paper parameters 16, average humidity), whereas dynamic paper parameters 16 contain a plurality of values ​​(e.g. humidity as a function of the width and length of the paper roll 10, 12). However, in principle it is also possible to use only a single paper parameter 16, such as, for example, the fiber orientation of the paper of the paper roll 10, 12 or the failure voltage of the paper of the paper roll 10, 12.

[0094] In one possible design, at least one of the paper parameters 16 is a dynamic paper parameter 16, the value of which is specified as a function of the width and / or length of the paper web of the paper rolls 10, 12. In contrast, static paper parameters have the same value along the entire paper web. Also suitable as paper parameters 16 are papermaking process parameters, i.e. process parameters used in the paper manufacturing of the respective paper rolls 10, 12 themselves.

[0095] The corrugator machine 2 has a data interface 28, via which the values ​​of the paper parameters 16 of the paper of the respective paper rolls 10, 12 are transmitted to the corrugator machine 2. For example, all values ​​are transmitted together as a single aggregate data set via the data interface 18 and are then immediately available, i.e. the corrugator machine 2 can access the paper data while the paper rolls 10, 12 are, for example, still stored in the roller bearing 14, or even earlier. In the embodiment shown here, the corrugator machine 2 is connected to the roller bearing 14 via the data interface 28.

[0096] In this case, each paper roll 10, 12 is assigned a data carrier 30 on which a single value of the paper parameter 16 of the respective paper roll 10, 12 is stored (offline solution). The data carrier 30 for the method described here is read out from the corrugated board machine 2. For this purpose, the corrugated board machine 2 has a suitable reader, for example as part of the data interface 28. In this case, the data carrier 30 is attached to the respective paper roll 10, 12 and is read with the reader, for example, when it is conveyed to the roll bearing 14. As an alternative or in addition to the described offline solution, an online solution is also possible, for example a cloud solution. For this purpose, for example, each paper roll 10, 12 has a separate ID (for example, attached to the paper roll 10, 12 instead of the data carrier 30), which is stored in the database 26 together with the paper data 16 of the respective paper roll 10, 12. By means of the ID, a specific paper roll 10, 12 is assigned its paper data 16, which is then determined and / or stored independently of the paper roll 10, 12. The paper parameters 16 also reach the database 26, for example, via a data interface 28, but the data interface 28 is not necessarily connected to the roller bearing 14, but to a suitable network. Optionally, the database 26 is designed separately from the corrugated board machine 2 and is connected to the corrugated board machine 2 for data transmission, for example via the Internet or via another network. Figure 1 In the embodiment, the database 26 is part of the corrugated board machine 2.

[0097] In principle, it is conceivable that the paper rolls 10, 12 are used multiple times, that is, after being supplied to the corrugated board machine 2, the paper rolls are not necessarily used completely, but only partially, and then removed from the corrugated board machine 2 and stored again. Figure 1 This is indicated by an arrow from the corrugating machine 2 toward the roller bearing 14 and is also illustrated by the fact that a partially consumed paper roll 10, 12 is shown in the roller bearing 14 and is therefore thinner than the other paper rolls 10, 12. If necessary, this partially used paper roll 10, 12 is supplied to the corrugating machine 2 again at a later point in time. In this case, therefore, the data carrier 30 is designed in such a way that it is reliably connected to the paper roll 10, 12 even in the case where the paper roll 10, 12 is supplied to and removed from the corrugating machine 2 several times. For example, for this purpose, the data carrier 30 is detachable and is removed during the supply of the paper roll 10, 12 and is reattached to the paper roll 10, 12 during removal and subsequent storage. In the case of the partially used paper roll 10, 12 shown here, the data carrier 30 is attached in such a way that it does not need to be removed when the paper roll 10, 12 is processed in the corrugating machine 2, i.e. remains on the paper roll 10, 12. To this end, Figure 1In the embodiment, the data carrier 30 is centered on the sleeve of the paper roll 10, 12. The statements about the data carrier 30 apply analogously to the ID already mentioned.

[0098] In this case, the corrugated board machine 2 also has a control unit 32, which is designed to carry out the method as described above. The control unit 32 is designed to carry out one or more of the described steps of the method and has a database 26 for this purpose. In addition, Figure 1 The control unit 32 in also contains the allocation rules 18 .

[0099] Individual aspects which are described or shown only in conjunction with an explicitly shown exemplary embodiment can in principle also be transferred to other exemplary embodiments independently of other concepts contained in the exemplary embodiment.

[0100] Reference numerals list

[0101] 2 Corrugated cardboard equipment

[0102] 4 Corrugated board webs

[0103] 6 Processing Units

[0104] 8 Expanding Machine

[0105] 10 First paper roll

[0106] 12 Second paper roller

[0107] 14 Roller bearing

[0108] 16 Paper Parameters

[0109] 18 Allocation Rules

[0110] 20 Quality parameters

[0111] 24 Sensors

[0112] 26 Database

[0113] 28 Data Interface

[0114] 30 Data carrier

[0115] 32 control unit.

Claims

1. A method for producing a corrugated board web (4) by means of a corrugated board machine (2), -in, providing a plurality of paper rolls (10, 12), each paper roll having a web of paper, - wherein the paper rolls (10, 12) are each characterized by a plurality of paper parameters (16), the plurality of paper parameters having separate values ​​for each of the paper rolls (10, 12), such that each of the paper rolls (10, 12) is individually characterized based on its value for the paper parameter (16), - wherein an allocation rule (18) is provided, which associates the paper parameters (16) of the two paper rolls (10, 12) with the quality parameters (20) for producing the corrugated board web (4) resulting from the combination of the two paper rolls (10, 12), - wherein the first paper roll (10) and the second paper roll (12) are selected from the paper rolls (10, 12) by means of the allocation rule (18) such that the quality parameter (20) is optimized, - wherein the corrugated board web (4) is manufactured by supplying the first and second paper rolls (10, 12) to the corrugated board machine (2), which then connects the paper webs of the first and second paper rolls (10, 12) to each other.

2. The method according to claim 1, in, The quality parameter (20) is a corrugated board parameter describing the properties of the corrugated board web (4) or depends on the corrugated board parameter.

3. The method according to any one of claims 1 or 2, in, The quality parameter (20) is a variation of an operating parameter of the corrugated board machine (2) during the production of the corrugated board web (4), or is dependent on said variation.

4. The method according to any one of claims 1 to 3, in, The allocation rule (18) is designed and the quality parameter (20) is selected to optimize the combination of the paper rolls (10, 12) whose paper parameters (16) compensate for one another.

5. The method according to any one of claims 1 to 4, in, One of the paper parameters (16) of the respective paper roll (10, 12) is humidity, and the quality parameter (20) is a measure of humidity differences.

6. The method according to any one of claims 1 to 5, in, During or after the production of the corrugated board web (4), the quality parameters (20) of the respective combinations of the two paper rolls (10, 12) are repeatedly measured and the paper parameters (16) of the two paper rolls (10, 12) are stored together with the quality parameters (20) as historical data in a database (26), Therein, the allocation rule (18) is based on the historical data.

7. The method according to any one of claims 1 to 6, in, The paper webs of the first and second paper rolls (10, 12) form different layers of the corrugated board web (4).

8. The method according to any one of claims 1 to 7, in, The number of paper parameters (16) of the respective paper roll (10, 12) is at least 10, preferably at least 100.

9. The method according to any one of claims 1 to 8, in, One or more of the paper parameters (16) are selected from the following paper parameters (16): fiber orientation of the paper of the paper roll (10, 12), failure stress of the paper of the paper roll (10, 12).

10. The method according to any one of claims 1 to 9, in, At least one of the paper parameters (16) is a dynamic paper parameter (16), the value of which is assigned as a function of the width and / or length of the paper web of the paper roll (10, 12).

11. The method according to any one of claims 1 to 10, in, The paper parameters (16) include a plurality of papermaking process parameters used to manufacture the paper of the corresponding paper roll (10, 12).

12. The method according to any one of claims 1 to 11, in, Before the respective paper roll (10, 12) is supplied to the corrugated board machine (2), the value of the paper parameter (16) of the paper of the paper roll (10, 12) is determined.

13. The method according to any one of claims 1 to 12, in, At least one subset of the paper rolls (10, 12), in particular each, has an ID, which is stored in a database (26) together with the value of the paper parameter (16) of the corresponding paper roll (10, 12), The corrugated board machine (2) requests the value of the paper parameter (16) of the corresponding paper roll (10, 12) from the database (26) based on the ID of the corresponding paper roll.

14. A corrugated board machine (2) comprising a control unit (32) designed to carry out the method according to any one of claims 1 to 13.

15. A computer program product comprising instructions which, when executed by the corrugated board machine (2), cause the corrugated board machine to select a second paper roll (12) for a first paper roll (10) from the plurality of paper rolls (10, 12) using the allocation rule (18) in the method according to any one of claims 1 to 13 such that the quality parameter (20) is optimized.

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