Method for determining locally distributed ready-to-use values ​​for a stamping station

Abstract

A method according to the invention for determining locally distributed preparation values ​​for a punching station, wherein a sensor field (22) comprising several sensor elements (23) measures the values ​​of a local distribution of forces which several tool elements (11) of an actuated tool (10) produce, is characterized in that a) during the measurement a number I of tool elements (11) W i and number K of sensor elements (23) S k are present, where for the indices i and k: 1 ≤ i ≤ I and 1 ≤ k ≤ K; b) that for each tool element (11) W i a length value LW ik determined and a length-related target force value FW i to be specified, where the length value LW ik the length of the tool element (11) W i in the measuring area (24) of the sensor element (23) S k and the target force value FW i the length-related nominal force of the tool element (11) W ispecify; c) that for each sensor element (23) S k a target force value F k is calculated, whereby: F k = Σ j (LW jk × FW j ) for a plurality of tool elements (23) W j , where for the index j: 1 ≤ j ≤ I; d) that in the measuring range (24) of each sensor element (23) S k an actual force value FM k is measured; e) and that for each value k the target force value F k with the actual force value FM k is compared and based on the identified deviations DF k = F k - FM k Ready-to-use values ​​ZRW k for preparation elements (31) ZE k The invention offers the advantage of determining the locally distributed preparation values ​​with sufficient accuracy for a satisfactory die-cutting result; it is preferably used in the preparation (creation of preparation sheets) in the context of the industrial production of die-cut products.

Description

invention

[0001] The invention relates to a method for determining locally distributed trimming values ​​for a punching station having the features of the preamble of claim 1. field of technology

[0002] The invention lies in the technical field of the graphic industry and there in particular in the field of so-called print finishing, especially the punching of flexible, sheet-shaped printing materials or the industrial, i.e. high-quality and highly productive production of punched products such as labels or folding boxes preferably made of paper, cardboard, paperboard, plastic or composite material State of the artState of the art

[0003] When punching, e.g. in flatbed punches, it can happen that tool elements, e.g. punching knives, of the punching tool or the so-called punching die do not produce the desired punching result, i.e. they do not punch the product to be punched completely. This can best be determined during a test punch before actual production. The same applies to embossing. In such a case, it can be helpful to increase the punching force locally, i.e. in the area of ​​the tool element that is not punching correctly. For this purpose, a so-called trim sheet can be produced. This is traditionally provided by a machine operator by hand at the point where the punching force is to be increased locally with one (or more) adhesive strips of a certain thickness, known as trim elements. The thickness of the trim sheet can also be changed locally in many places.During production, the trim sheet is placed under the punching tool and, thanks to its adjusted thickness profile, locally increases the punching forces so that overall satisfactory products are produced.

[0004] EP2327521B1 discloses a method for trimming tools of a flatbed sheet punching and / or embossing machine with at least one punching and / or embossing station each having an upper and a lower platen. The pressure distribution during punching and / or embossing is measured using a flat, particularly foil-shaped, pressure distribution sensor extending over the surface of the tool, or using a so-called measuring mat. From this, the trimming requirement distribution is calculated, and the tool is trimmed accordingly. EP3153286B1 discloses a similar system.

[0005] DE102015106344B4 discloses a machine-specific trimming sheet that is derived directly from deformation measurements.

[0006] To create a suitable trim sheet, i.e. one that adequately compensates for potential punching errors, it is therefore necessary to be able to determine trim values, preferably thickness values, with sufficient accuracy for creating trim elements of the trim sheet. Technical task

[0007] It is an object of the present invention to provide an improvement over the prior art, which in particular makes it possible to determine the locally distributed trimming values ​​for a satisfactory punching result with sufficient accuracy. Inventive solution to the problem

[0008] This object is achieved according to the invention by a method according to claim 1.

[0009] Advantageous and therefore preferred developments of the invention emerge from the subclaims as well as from the description and the drawings.

[0010] A method according to the invention for determining locally distributed dressing values ​​for a punching station, wherein a sensor field comprising several sensor elements measures the values ​​of a local distribution of forces which cause several tool elements of an actuated tool, is characterized in that a) during the measurement a number I of tool elements W i and number K of sensor elements S k are present, where for the indices i and k: 1 ≤ i ≤ I and 1 ≤ k ≤ K; b) that for each tool element W i a length value LW ik determined and a length-related target force value FW i be specified, where the length value LW ik the length of the tool element W i in the measuring range of the sensor element S k and the target force value FW i the length-related target force of the tool element W i c) that for each sensor element S k a target force value F kis calculated, where: F k = Σ j (LW jk × FW j ) for a plurality of tool elements W j , where for the index j: 1 ≤ j ≤ I; d) that in the measuring range of each sensor element S k an actual force value FM k is measured; e) and that for each value k the target force value F k with the actual force value FM k is compared and based on the deviations found DF k = F k - FM k Adjustment values ​​ZRW k for dressing elements ZE k be calculated. Advantageous embodiments and effects of the invention

[0011] The invention advantageously enables the locally distributed trimming values ​​to be determined with sufficient accuracy for a satisfactory punching result. The invention provides a combined measurement and calculation method for this purpose.

[0012] The invention advantageously enables a significant reduction in effort and thus a significant time saving when setting up a punching station, especially when setting up so-called initial orders. The invention therefore enables cost savings, especially for the operating personnel, and enables higher productivity through additional production time on the punching station.

[0013] The state of the art has not yet taken into account that a discretized pressure measuring mat determines a total force per measuring field that acts on this measuring field.

[0014] For large-area loads (significantly larger than the discretization of the measuring mat) this can be interpreted as a pressure distribution.

[0015] The invention is based on the observational finding that the punching blades of a punching tool or punching die instead generate very local loads whose respective force per unit length is ideally constant over the length of the punching blades, i.e. the tool elements, and has a value suitable for the substrate. The force acting on a measuring element of the measuring mat therefore depends both on this value and on the length of the tool element within a measuring range of the measuring element. If this length is not taken into account, the measured force value, i.e. the target force value, cannot be calculated. This tool length per measuring field can be derived from the preliminary stage data and, according to the invention, is incorporated into the evaluation process of the measured data.

[0016] The invention is further based on the following observational finding: If the measured force value deviates downwards from the target value in a measuring field, this point has a local adjustment requirement ZRW k greater than zero, meaning the trimming arc must be locally thicker. If the measured force value in a measurement field deviates upwards from the target value, the surrounding area (e.g., all neighboring measurement fields) has a trimming requirement greater than zero. A reasonable size of the surrounding area to be considered for a measurement field can be determined experimentally once in advance and then provided to the process as an input value.

[0017] One goal of dressing is to achieve the same punching or creasing result across the substrate. To achieve this, the tool element-specific force must be approximately the same across the sheet or adjusted by local thickness changes of a dressing sheet. The value of the required thickness change (per unit of punching force change to be achieved) can be determined experimentally in advance and can be adjusted to the capabilities of the manufacturing process for the dressing sheet. This value can also be provided to the process as an input value.

[0018] The determined make-ready requirement can also be geometrically low-pass filtered to eliminate high-frequency noise in the make-ready requirement. Calculated make-ready values ​​that lie between the thickness resolution of the make-ready sheet manufacturing process can be rounded up or down. The make-ready requirements determined in this way are then implemented in the make-ready sheet as locally distributed thickness changes, preferably automated, for example, by printing the make-ready sheet with a thickness-changing ink.

[0019] The tool elements are preferably designed as knives, alternatively as creasing lines or pressure rubbers. The length-related target force value FW i is preferably a substrate-dependent value. Further developments of the invention

[0020] Preferred developments of the invention (hereinafter referred to as "developments") are described below. These can also be combined with one another, where not technically mutually exclusive.

[0021] A further development can be characterized by the fact that for only one value k using the adjustment value ZRW k a dressing element ZE k or that for several values ​​k using the adjustment value ZRW k one dressing element ZE each k or that for each value k using the adjustment value ZRW k one dressing element ZE each k is created. Preference is given to those values ​​of k for which there is actually a need for adjustment.

[0022] A further training can be characterized by the fact that in step e the adjustment values ​​ZRW kbe calculated as local height values ​​or thickness values ​​of a trim sheet, ie for the respective trim elements ZE k of the trimming sheet. This is preferred if the punching force needs to be increased locally.

[0023] A further training can be characterized by the fact that in step e the adjustment values ​​ZRW k are calculated as adjacent height values ​​or thickness values ​​of a trim sheet, ie for the adjacent trim elements of a respective trim element ZE k of the trimming sheet. This is preferred when the punching force is to be reduced locally, ie, conversely, increased in the local area.

[0024] A further development can be characterized by the fact that calculations of the local height values ​​and the neighboring height values ​​are combined for the production of a trim sheet.

[0025] Further training can be characterized by the fact that previously experimentally determined altitude values ​​or changes in altitude values ​​are specified and used.

[0026] A further development can be characterized by the fact that a trimming sheet is produced which contains all k trimming elements ZE k includes.

[0027] A further development can be characterized by the fact that the trimming sheet is manufactured additively.

[0028] A further training course may be characterized by the fact that the overlay sheet is printed. A further training course may be characterized by the fact that the overlay sheet is printed using the inkjet printing process.

[0029] A further development can be characterized by the fact that the trim sheet is produced automatically by locally gluing sections of a trim tape.

[0030] A further development can be characterized by the fact that the trim sheet is produced manually by locally gluing sections of a trim tape, with the gluing locations being displayed to an operator.

[0031] A further development can be characterized by the fact that the trim sheet is produced manually by locally gluing sections of a trim tape, whereby the thickness of the adhesive tape is displayed.

[0032] A further development can be characterized by the fact that the trimming sheet is produced subtractively.

[0033] A further development can be characterized by the fact that the trim sheet is produced automatically by locally removing layers of a multi-layer trim sheet.

[0034] A further development can be characterized in that steps d and e of the method are carried out iteratively, whereby intermediate dressing sheets are produced, and that the iteratively measured dressing values ​​ZRW k merged and used to create a final trim sheet. In each subsequent iteration step, a new measurement can be performed using the previously created intermediate trim sheet (as the sum of its previously created intermediate trim sheets) or all previously created intermediate trim sheets. Ultimately, only the final trim sheet is used for production.

[0035] A further training can be characterized by the fact that in step c the following applies: only for such tool elements W j which are located at least partially in the measuring range of a sensor element S k are located, ie for which the length value LW jk≠ 0. Tool elements that do not have a local effect can thus be ignored.

[0036] An alternative further development can be characterized by the fact that in step c the following applies: for all tool elements W j = W i .

[0037] A further development can be characterized in that step d is carried out with a measuring foil or measuring mat, which the sensor elements S k This is preferably flexible and can comprise electronic measuring cells arranged in a matrix.

[0038] A further development can be characterized by the fact that the measuring foil or measuring mat is placed next to the tool. It is preferably located behind the tool, i.e., on its back.

[0039] A further development can be characterized by the fact that tool data from the prepress stage is provided in step b.

[0040] A further training can be characterized by the fact that the tool data reflects the type of the respective work element W i include.

[0041] A further development can be characterized by the fact that the tool data contains the location and / or angle of the respective work element W i include.

[0042] A further development can be characterized by the fact that in step c the target force values ​​F k calculated as absolute values.

[0043] A further development can be characterized by the fact that in step c the target force values ​​F k calculated as relative values.

[0044] A further training can be characterized by the fact that in step d the actual force values ​​FM k be measured in a measurement time window in which the effect of the tool element is expected.

[0045] A further training can be characterized by the fact that the actual force values ​​FM kwithin the measurement time window with a specified temporal resolution. The resolution is preferably selected so fine that the peak of the punching force can be precisely captured and measured.

[0046] A further development can be characterized by performing step d in a measuring station different from the punching station. This is advantageous because production does not need to be interrupted for the measuring.

[0047] A further training can be characterized by the fact that the calculations of steps b and e are carried out using a digital computer.

[0048] The features and combinations of features disclosed in the above sections Technical Field, Invention and Further Developments as well as in the following section Exemplary Embodiments represent - in any desired combination with one another - further advantageous developments of the invention. Embodiments of the invention and figures

[0049] The Fig. 1 to 3 show a preferred embodiment of the invention and the further developments.

[0050] Fig. 1 shows a schematic representation of a (longitudinal) sectional view of a preferred machine configuration when carrying out a preferred embodiment of the method according to the invention. In Fig. 1 shows a flatbed die cutter 1 with a processing direction 1a for sheets and with an upper and movable lower tool. The die cutter comprises, in the processing direction, a feeder 2 for a stack of printed products to be processed, a feed table 3, a die cutting station 4, a stripping station 5, a blanking station 6, and a station 7 for sample sheet removal. The sheets 8 to be die cut are processed individually and automatically, for which purpose the die cutter comprises or is connected to a digital computer 17 that controls the production process. The (upper) tool 10 is designed as a die cutting tool and has corresponding tool elements 11, i.e., die cutting elements; opposite and interacting with the lower tool, the counter tool, is arranged.

[0051] The machine configuration optionally includes (shown on the right) a prepress device 15, e.g., a digital computer, in particular with a data memory 16; this device is preferably connected to the computer 17 for transmitting data.

[0052] The machine configuration further includes an optional measuring station 20 with a measuring device 21 for the automated measurement of the values ​​of a local distribution of forces during punching (shown as an example at the bottom left) and a device 32 for the automated production of make-ready sheets 30 based on the measured punching forces, which are processed by computer technology according to the invention (shown as an example at the top left); these two stations are also preferably connected to the computer 17 for data transmission. As an alternative to display, the punching forces can also be measured directly in the flatbed punch 1 or in its punching station 4; a separate measuring station 20 is then not required.

[0053] The measuring device 21 comprises a sensor field 22 with a plurality of sensor elements 23 arranged on a (preferably square) measuring grid, with each sensor element 23 being assigned its own measuring range 24. Each measuring range has dimensions 24a (see. Fig. 3).

[0054] The automated production device 32 can preferably produce trim sheets 30, intermediate trim sheets 30a, and / or final trim sheets 30b. Production can be effected by creating or applying trim elements 31: the creation can preferably be effected by applying a liquid or pasty (and curing or curable) trim material, such as an ink; the application can preferably be effected by applying a self-adhesive trim tape or sections thereof, such as pieces of adhesive tape.

[0055] The measurement is therefore preferably performed in measuring station 20, while punching station 4 can be operated for actual production. After the measurement is complete, tool 10 is removed from measuring station 20. Likewise, the trim sheet 30 created to fit tool 10 is removed from device 32. Both are then inserted into punching station 4 for punching-defect-free production.

[0056] The measuring system 20 and the device 32 can be arranged as a single unit, as shown, for example, one above the other or directly adjacent to each other. Alternatively, the two units can be arranged separately and, for example, remotely from each other; in this case, both units are preferably connected to the digital computer 17 via separate connections.

[0057] Fig. 2 shows a schematic flow chart of a preferred embodiment of the method according to the invention with the following steps: Step 40: A computer, preferably the digital computer 17, is provided, which carries out the calculations 40a including the comparisons.

[0058] Step 41: The (punching) tool 10 with the (punching) tool elements 11, preferably the punching blades, is prepared for a future punching job. Preparation preferably takes place in the measuring station 20 or alternatively directly in the punching station 4. This also determines the number I of tool elements W. i known, where: 1≤i≤I.

[0059] Step 42: Digital data on the tool 10 are provided, preferably data on the positions and angles of all its tool elements 11 and their respective length values, as well as data on the target force values. This data is transmitted to the provided computer 17, preferably from a data storage 16 of the prepress stage 15. The provided or specified values ​​preferably include the length-related target force values ​​FW. i .

[0060] Step 43: The measuring device 20 is optionally provided, provided that the measurement of the punching forces is not performed directly in the punching station 4; the measuring device comprises the sensor field 22 with the sensor elements 23. The measuring device 20 is preferably connected to the provided computer 17 for data transmission, in particular for transmitting the measured values. Thus, the number K of sensor elements S k known, where: 1 ≤ k ≤ K.

[0061] Step 44: Digital data are provided for the measuring device 20, preferably data for its measuring areas 24 of a measuring grid, e.g. the locations and dimensions 24a of the measuring areas 24.

[0062] Step 51: The length values ​​LW ik determined or calculated.

[0063] Step 52: The target force values ​​F k calculated with F k = Σ j (LW jk × FW j ) \for a plurality of tool elements W j , where for the index j: 1 ≤ j ≤ I. Preferably, the calculation is carried out for all tool elements 11 of the tool 10.

[0064] Step 53: The actual force values ​​FM kmeasured. At least one test punching is performed, preferably in measuring station 20. The substrate used and to be punched should match the substrate used in subsequent production or at least have similar relevant parameters, such as thickness.

[0065] Step 54: For each value k, the target force value F k with the actual force value FM k (computationally) compared and deviations DF k = F k - FM k determined or calculated. There are three cases: a) F k > FM k , b) F k ≈ FM k or c) F k < FM k In case a, there is a local need for adjustment in the area of ​​the locally measuring sensor element 23, in case b there is no need for adjustment, and in case c there is a need for adjustment in the local environment of the area of ​​the locally measuring sensor element 23.

[0066] Step 55: Based on the determined or calculated deviations, adjustment values ​​ZRW k , e.g. thickness values, for trimming elements ZE k These values ​​can preferably be transferred to the device 32 and used there for producing a make-ready sheet 30.

[0067] Fig. 3 shows six examples of different sensor elements 23 and their measuring ranges 24 with respective linear dimensions 24a, here exemplary square areas: Top left: In area 24, only one tool element 11 is arranged, here at an angle of 0°. Its length value LW ik Let 1 unit of length LE be (relative to the linear dimension 24a). The length-related target force value FW i be 400 N / LE. The target force value F k calculates to 400 N, for example. The actual force value FM k is measured at 400 N. This results in a dressing value ZRW k= 0. No local trimming is required.

[0068] Top center: In area 24, only one tool element 11 is arranged, here at an angle of 0°. Its length value LW ik Let 1 unit of length LE be (relative to the linear dimension 24a). The length-related target force value FW i be 500 N / LE. The target force value F k calculates to 500 N, for example. The actual force value FM k is measured at 500 N. This results in a dressing value ZRW k = 0. No local trimming is required.

[0069] Top right: In area 24, only one tool element 11 is arranged, here, for example, at a first angle different from 0°. Its length value LW ik be 1.25 length units LE (relative to the linear dimension 24a). The length-related target force value FW i be 400 N / LE. The target force value F k calculates to 500 N, for example. The actual force value FMk is measured at 500 N. This results in a dressing value ZRW k = 0. No local trimming is required.

[0070] Bottom left: In area 24, only one tool element 11 is arranged, here as an example at the first angle different from 0°. Its length value LW ik be 1.25 length units LE (relative to the linear dimension 24a). The length-related target force value FW i be 400 N / LE. The target force value F k calculates to 500 N, for example. The actual force value FM k is measured at 400 N. This results in a dressing value ZRW k > 0. Local trimming is required. The punching force must be increased locally.

[0071] Bottom center: In area 24, only one tool element 11 is arranged, here as an example at a second angle different from 0°. Its length value LW ikbe 0.4 length units LE (relative to the linear dimension 24a). The length-related target force value FW i be 400 N / LE. The target force value F k calculates to 160 N, for example. The actual force value FM k is measured at 130 N. This results in a dressing value ZRW k > 0. Local trimming is required. The punching force must be increased locally.

[0072] Bottom right: In area 24, two tool elements 11 are arranged, both at an angle different from 0°. The length values ​​LW ik be 0.4 length units LE and 1 LE (relative to the linear dimension 24a). The length-related target force values ​​FW i be 400 N / LE and 200 N / LE. The target force values ​​F k calculated as 160 N and 200 N, ie a total of 360 N. The actual force value FM k is measured at 400 N. This results in a dressing value ZRW k< 0. Local trimming is required. The punching force must be reduced locally.

[0073] These examples show that if the discretization of the sensor field 22, e.g., a measuring mat, is known, the tool element length LWik expected in each measuring field k can be calculated from the specified target values ​​and the tool-specific distribution of the tool elements 11 (number, angle). Together with the force target values ​​FWi, the expected force measurement value per measuring element is F k .

[0074] Optionally, sensor fields 22 that do not contain a tool element 11 can be excluded from the calculation so that any noise in the measurement signal does not lead to artifacts in this area. List of reference symbols 1 flatbed punch 1a Processing direction 2 investors 3 Plant table 4 punching stations 5 Stripping station 6 depaneling station 7 Sample sheet removal 8 sheets 10 tools 11 tool elements 15 Prepress 16 Data storage / data 17 digital computers 20 measuring stations 21 Measuring device 22 Sensor field 23 sensor element(s) 24 measuring range(s) 24a Dimension(s) Measuring range(s) 30 finishing sheets 30a Intermediate dressing sheet 30b Final trim sheet 31 finishing elements 32 Device for producing make-ready sheets 33 Finishing material 34 finishing tape 40 Provisioning Calculators 40a Calculations 41 Providing the tool with tool elements 42 Providing data (tool) 43 Provision of the measuring device with sensor elements 44 Provision of data (measuring device) 51 Determining the length values 52 Calculate target force values 53 Measuring actual force values 54 Computational Comparisons 55 Calculating the trimming values QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 2327521B1

[0004] EP 3153286B1

[0004] DE 102015106344B4

[0005]

Claims

[1] Method for determining locally distributed dressing values for a punching station, wherein a sensor field (22) comprising several sensor elements (23) measures the values of a local distribution of forces which cause several tool elements (11) of an actuated tool (10), characterized by , a) that during the measurement a number I of tool elements (11) W i and number K of sensor elements (23) S k are present, where for the indices i and k: 1 ≤ i ≤ I and 1 ≤ k ≤ K; b) that for each tool element (11) W i a length value LW ik determined and a length-related target force value FW i be specified, where the length value LW ik the length of the tool element (11) W i in the measuring range (24) of the sensor element (23) S k and the target force value FW i the length-related target force of the tool element (11) W i indicate; c) that for each sensor element (23) S k a target force value F k is calculated, where: F k = Σ j (LW jk × FW j ) for a plurality of tool elements (23) W j , where for the index j: 1 ≤ j ≤ I; d) that in the measuring range (24) of each sensor element (23) S k an actual force value FM k is measured; e) and that for each value k the target force value F k with the actual force value FM k is compared and based on the deviations found DF k = F k - FM k Adjustment values ZRW k for dressing elements (31) ZE k be calculated. [2] Method according to claim 1, characterized by that for only one value k using the adjustment value ZRW k a dressing element (31) ZE k or that for several values k using the adjustment value ZRW kone dressing element each (31) ZE k or that for each value k using the adjustment value ZRW k one dressing element (31) ZE k is created. [3] Method according to one of claims 1 or 2, characterized by that at step e the adjustment values ZRW k are calculated as local height values of a trimming arc (30), ie for the respective trimming elements (31) ZE k of the dressing sheet (30). [4] Method according to one of claims 1 or 2, characterized by that at step e the adjustment values ZRW k are calculated as adjacent height values of a trimming sheet (30), ie for the adjacent trimming elements (31) of a respective trimming element (31) ZE k of the dressing sheet (30). [5] Method according to one of the preceding claims, characterized by that a dressing sheet (30) is produced which contains all k dressing elements (31) ZE k includes. [6] Method according to claim 5, characterized by that the trimming sheet (30) is manufactured additively. [7] Method according to one of the preceding claims, characterized by that steps d and e of the method are carried out iteratively, whereby intermediate dressing sheets (30a) are produced, and that the iteratively measured dressing values ZRW k brought together and used to produce a final trim sheet (30b). [8] Method according to one of the preceding claims, characterized by that in step c applies: only for such tool elements (11) W j which are located at least partially in the measuring range (24) of a sensor element (23) S k are located, ie for which the length value LW jk ≠ 0. [9] Method according to one of the preceding claims 1 to 7, characterized by that in step c the following applies: for all tool elements (11) W j = W i . [10] Method according to one of the preceding claims, characterized by that step d is carried out in a measuring station (20) different from the punching station (4).

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