Method for determining at least one detection point for detecting the material flow on a circuit board

Abstract

The invention relates to a method for determining at least one detection point, in particular a plurality of detection points, for detecting the material flow on a circuit board in a processing operation, in particular a shaping operation, comprising the following steps: simulating a simulation set, comprising a plurality of processing operations of a plurality of different simulation circuit boards; determining the material flow of the circuit boards in the simulated processing operations; determining a variance of the material flow between the simulated processing operations; determining the at least one detection point on the basis of the determined material flow and / or the determined variance of the material flow.

Description

[0001] Method for determining at least one detection point for detecting the material flow on a circuit board

[0002] The invention relates to a method for determining at least one detection point, in particular a plurality of detection points, for detecting the material flow on a blank in a machining process, in particular a forming process.

[0003] Methods for processing blanks, for example forming processes, in particular deep-drawing processes, are generally known from the prior art. At the beginning of the forming process, the blank, for example a flat sheet, is placed on a sheet holder of the processing device. A ram with a die can then move towards the blank. As soon as the blank holder, the blank and the die are in contact, the blank holder is displaced downwards. As the blank holder is displaced, the sheet is pulled over the punch. The shape of the die and punch determines the geometry of the drawn part, which represents the result of this process step and can also be referred to as an intermediate product. During forming, the sheet is plastically stretched. In addition, a relative movement also occurs between the sheet and the surface of the die and the blank holder, which is referred to below as material flow.

[0004] Material flow can be measured, for example, by measuring the position of the edge of the intermediate product after forming. This edge is also referred to as the drawn part edge. As material flow increases, the orthogonal distance between the edge of the intermediate product and the punch outline decreases.

[0005] Material flow is a key parameter for controlling the quality of the forming process. In this context, it should be emphasized that material flow analysis can also be used when process parameters are manually selected. For example, excessive material flow in the blank holder area can lead to the formation of wrinkles. Conversely, insufficient material flow may lead to cracking. This relationship allows material flow to be considered as a proxy for the quality of the final product and the component.

[0006] Determining the sampling points, i.e. the positions at which the material flow is to be measured during production, is a challenge. For example, if sampling points are selected that have a low variance in the material flow, the fluctuation in the material flow may be underestimated and incorrect or incomplete conclusions may be drawn.

[0007] The invention is based on the object of specifying an improved method for determining at least one detection point for detecting the material flow on a circuit board.

[0008] The object is achieved by a method according to claim 1. The dependent claims relate to possible embodiments.

[0009] As described, the invention relates to a method for determining at least one detection point, in particular a plurality of detection points, for detecting the material flow on a blank during a machining process, in particular a forming process. The method comprises the following steps:

[0010] Simulating a first machining process of a first simulation board having a first set of semi-finished product properties;

[0011] Simulation of at least one second machining process of at least one second simulation board, in particular of a simulation set comprising a plurality of machining processes of a plurality of different simulation boards, which second simulation board has a second set of semi-finished product properties, wherein at least one process parameter and / or process state of the first machining process is different from at least one similar process parameter and / or process state of the at least one second machining process and / or at least one semi-finished product property of the second set of semi-finished product properties is different from at least one similar semi-finished product property of the first set of semi-finished product properties; Determination of the material flow of the boards in the simulated machining processes;

[0012] Determination of a variance of the material flow between the simulated machining processes;

[0013] Determining the at least one detection point based on the determined material flow and / or the determined variance of the material flow.

[0014] In other words, in the described method, at least one first machining process is initially simulated based on at least one first simulation blank having a first set of semi-finished product properties. In addition, at least one second machining process is simulated using at least one second simulation blank having a second set of semi-finished product properties. Specifically, a simulation set can be simulated that includes a plurality of machining processes and a plurality of simulation blanks. In each of the machining processes, a plurality of simulation blanks can in turn be simulated. The machining processes differ in at least one process parameter and / or at least one process state.In other words, a multitude of process parameters and / or process states of different machining processes can be simulated with a multitude of semi-finished product properties of different simulation blanks. Process states can be understood as, for example, the surface temperatures of a tool and / or the blank. The material flow can be influenced by changing the contact pressure distribution between the blank holder and the die. The contact pressure can be influenced, for example, by selecting the forces of displacement cylinders acting on the blank holder or by adjusting drawing aids. These values ​​can be used, for example, as process parameters and can be combined into a vector. If the values ​​of the components of two vectors differ, these are two different process parameter combinations.With the additional use of a lubricant application, the number of components of this vector can be more than 1000.

[0015] For example, the simulations can be performed as multiple FE (finite element) simulations of the respective production process, with the semi-finished blank properties and the process parameters and / or process states being varied between the individual simulations. A single simulation can be referred to as a simulation variant and represents, for example, the simulation of a first machining process with first process parameters and / or process states using a first simulation blank with a first set of semi-finished blank properties.

[0016] The material flow of the simulation blanks can then be determined in the simulated machining processes. This results from the described simulations, which ultimately describe real machining processes by modeling the simulation blanks and the machining device. Furthermore, in addition to determining the material flow of the blanks, the variance of the material flow between the simulated machining processes is also determined. As a result, at least one detection point can be obtained that is based on the determined material flow and / or the determined variance of the material flow. Based on the results of the simulations, suitable, in particular ideal, detection points, i.e. locations for measuring the material flow with a measuring system, can be determined during series production.

[0017] Furthermore, it has been shown that measuring the material flow at acquisition points with a low variance in the material flow is not suitable, since at these points, changed semi-finished product properties or process parameters have no or only a minor effect on the material flow. The proposed method therefore makes it possible to consider both the material flow and the variance in the material flow between the various simulations and to automatically evaluate the simulation results. In this case, it can be provided to visualize the variance in the material flow on one of the calculated drawn parts or the intermediate product obtained from the simulated machining processes based on the obtained simulation result, for example, an FE mesh, and / or to further evaluate it automatically. This step results in the specific acquisition points for measuring the material flow during operation of the production system.Finally, the coordinates of the locations are transformed from the simulation coordinate system to the coordinate system of the material flow measurement system. This allows the material flow to be measured at detection points that, according to the simulation results, exhibit a particularly large variation in material flow.

[0018] As described, the detection point on a printed circuit board is determined using the method proposed herein. The term "printed circuit board" encompasses all states or forms of change of the printed circuit board. During the processing, the printed circuit board is formed, as described, into an intermediate geometry, i.e., an intermediate component or intermediate product is produced, and then shaped into a final geometry, i.e., a final product or finished component is produced. The detection points can be determined for each stage. Specifically, the detection point on the printed circuit board is determined for the processing step in which an intermediate geometry or intermediate product is produced from the original printed circuit board. The designation can therefore be changed within the scope of the description, so that the detection point can also be determined, for example, "on the intermediate component" and the like.

[0019] As previously described, determining the material flow serves to characterize the machining process. For example, excessive material flow in the area of ​​the blank holder can lead to the formation of wrinkles, while insufficient material flow can potentially lead to cracking. This relationship makes it possible to consider the material flow as a proxy for the quality of the final product and the component. Material flow can also correlate with other quality characteristics, such as the geometry of the produced component or the intermediate geometry. For example, elastic springback is also influenced by the material flow, thus influencing the properties of the intermediate product and thus also the final product.

[0020] The method can further provide for a minimum material flow to be specified, wherein in determining the material flow, only potential detection points are determined at which a material flow above the minimum material flow occurs in the simulation. As already described, in order to determine a suitable detection point, it is necessary, on the one hand, that the variance of the material flow in the machining process at the detection point is as high as possible so that fluctuations in the process can be well resolved there. The described embodiment also provides that a minimum material flow must occur in the simulation in order to classify that location as a detection point. In other words, locations in the simulation can be excluded as potential detection points if the material flow there does not at least assume the minimum material flow.In particular, it is excluded that recording points are selected where the variance of the material flow is high, but which have a low absolute value of the material flow, so that fluctuations, for example in the measuring process, are particularly pronounced there.

[0021] As described, the method essentially determines a detection point or a plurality of detection points at which the material flow is to be measured in a real-life machining process. The measured material flow can be used as a parameter that allows conclusions to be drawn about the quality of the intermediate products. The simulation or the determination of the detection points can already take into account the areas in the process where material flow measurement is appropriate.According to one embodiment of the method, it can be provided that the determination of the detection point is carried out in a limited manner on at least one characteristic region of the blanks, in particular an edge, for example a drawn part edge, and / or a starting edge and / or a trailing edge and / or a position of a drawing aid of a tool in the machining process, wherein the at least one detection point is determined within the at least one characteristic region. At least one such characteristic region can be weighted when determining the detection point. In particular, different such characteristic regions can be weighted differently.

[0022] As described, the material flow does not only occur in the area of ​​the blank holder, but specific characteristic areas of the blanks can be selected that are suitable for measurement, for example, the starting edge and / or the trailing edge and / or an edge of the drawn part produced from the blank. Basically, on sufficiently curved surfaces in the contact area between the tool and the sheet metal surface, relative movements occur in the contact area that leave visible marks on the sheet metal surface. These are marks in the form of scratches on the surfaces of the intermediate product that are caused by the relative movement between the tool surface and the sheet metal surface. The starting edge is the beginning of the aforementioned marks. If the material flow changes, the position of the starting edges on the intermediate product also changes.When a lead-in edge is created, a trailing edge is always induced on the opposite side of the sheet. The position of this edge can also be used to assess material flow. The drawing edge is defined as the edge of the intermediate component into which the blank is machined or formed, particularly deep-drawn, during the machining process. In this context, detection points on the respective drawn part that exhibit a particularly large variance in material flow and are located near the edge of the drawn part or a lead-in or trailing edge are particularly well suited for measuring material flow.

[0023] As already described, the method can be used to determine at least one detection point at which the material flow is to be measured or recorded in the real process. Based on the results of the simulations or based on the determination of the detection point, the user can, for example, manually select sensible locations at which the material flow is to be measured. For example, as described in the present embodiment, characteristic areas of the blanks or the intermediate components can be taken into account for this purpose. For example, all potential detection points that are not located in a characteristic area can be excluded. Therefore, it can also be automatically taken into account that the specific detection points should be located near the edge of the drawn part or near leading and trailing edges.

[0024] The method can further provide for at least two detection points, in particular a defined number of detection points, to be determined, wherein the at least two detection points have a minimum distance from one another. As described, the method selects detection points for which a high variance in the material flow has been determined. According to the described embodiment, it is further taken into account that the detection points have a certain spatial distance from one another. The detection points can, for example, be specified by a user by selecting specific detection points that have the required minimum distance. Alternatively or additionally, the detection points that have a large variance in the material flow could also be determined automatically. In this case, it can be provided, in particular, that a defined number of detection points is specified, in particular by a user.For example, it is possible to specify how many detection points should be determined using the method described here. For example, it is possible to specify how many detection points should be determined or at how many detection points in the actual production process the material flow should be measured. Knowing the number of required detection points further improves the determination of the detection points. For example, it is possible to search for a specified number "n" of detection points with a pronounced variance in the material flow, where "n" is defined by the user or is fixed. The number "n" could, for example, be a value of 50.

[0025] As previously described, it can be ensured that the individual detection points are not too close to one another, but are spaced apart by the minimum distance. Otherwise, in the worst case, the material flow is only considered locally in a region. Ideally, the locations for determining the material flow should be as close as possible to the edge of the drawn part or to a leading or trailing edge, as also previously described. This can be achieved, for example, by limiting the search for detection points to at least one characteristic area. This criterion can also be checked automatically, since the location of these characteristic areas, for example the edge and the edges, can be determined from the simulation results.For example, it is also possible, especially by a user, to select the characteristic areas in which the detection points should be located or across which characteristic areas the detection points should be distributed. It is also possible to define specific exclusion areas in which no detection points should be determined, for example, if measuring the material flow is not possible in such exclusion areas.

[0026] The described method can be carried out, for example, by first determining the number of detection points sought or to be determined. Furthermore, it is determined in which characteristic regions the detection points are to be determined, or what proportion of the total number of detection points are to be determined in which characteristic regions, or whether there are exclusion regions in which no detection points are to be determined. Subsequently, for example, in at least one characteristic region or in each of the characteristic regions, the location or node of the model is determined as the first detection point that has a material flow in the simulation above the minimum material flow and at which the variance of the material flow is highest.

[0027] Based on this, the minimum distance around the first determined detection point can be specified, for example, 50 mm. This excludes all potential detection points within the minimum distance around the first determined detection point. Finally, the second detection point can be determined as the location or node in the model that is not excluded and that has the highest material flow variance above the minimum material flow. The minimum distance can again be applied around the second determined detection point to exclude potential additional detection points that are too close to the already determined detection points. The described procedure can be continued until the specified number of detection points has been determined.

[0028] In a further development of the described method, it can be provided that at least one detection point is excluded that correlates above a defined correlation value with at least one previously determined detection point in relation to the material flow. As described, the material flow is determined based on the simulation variants, i.e., based on the simulations of the machining processes of the various simulation blanks. When determining a further detection point, for example, a second detection point or any other detection point, the correlation of the material flow at the second detection point to the at least one previously determined detection point can be determined.

[0029] If the correlation of the material flow at the detection point to be determined, for example, the second detection point, exceeds the correlation value with respect to at least one previously determined detection point, the potential detection point to be determined is excluded and, instead, another potential detection point is determined as the second detection point that correlates with the already determined detection points below the defined correlation value. Furthermore, potential detection points can be specifically selected that have the lowest possible correlation value. The described embodiment thus advantageously enables there to be no or only a weak causal connection between the material flow at the individual detection points. In particular, it is possible to perform a correlation analysis in the simulation to take this aspect into account.

[0030] The method can further provide for a defined number of detection points to be determined iteratively. This can ensure that the detection points can be determined or modified in such a way that the subsequent measurement of the material flow in the actual production process is as robust as possible against fluctuations. As described, the individual detection points can be determined one after the other, whereby the determination of a first detection point excludes potential detection points for the determination of a second detection point, in particular due to the correlation, the minimum distance, the characteristic range, and the like. In other words, the determination of a preceding detection point includes the selection of the remaining potential detection points for the determination of the subsequent detection point, in particular by taking into account the minimum distance, correlation, and characteristic range.

[0031] The described method can further be developed such that the sets of semi-finished product properties are determined based on a variance of a starting set, in particular comprising a lubricant quantity and / or an elasto-plastic property and / or a tribological property, and / or based on a recording of sets of semi-finished product properties of at least one batch of real blanks. As described above, the variance of the material flow is to be determined by the various simulation blanks in the various simulated machining processes in order to be able to determine suitable recording points for measuring the material flow in the real production process. The different sets of semi-finished product properties assigned to the different simulation blanks can be determined, for example, by varying a starting set, for example by changing the individual semi-finished product properties.The starting set, which can also be referred to as the target set or measured set, forms the starting point for the variation. In other words, a starting set of semi-finished product properties can be provided that the ideal board exhibits. Each individual value of these semi-finished product properties can then be varied to obtain different sets of semi-finished product properties that can be assigned to the different simulation boards. Alternatively, it is possible to measure a batch of real boards in order to determine the actual fluctuations in the semi-finished product properties. These can then be assigned to the simulation boards. The starting set can be predetermined or formed by (randomly) selecting previously measured semi-finished product properties.

[0032] In other words, to use simulations to determine the fluctuation in material flow expected in series production, it is possible to vary the semi-finished product properties, particularly the elasto-plastic properties and tribological properties of the blanks, in the simulation model. For example, using a sampling method, variants of semi-finished product properties can be generated that are intended to represent the fluctuation in the properties of the actual blanks. However, with this approach, it should be noted that semi-finished product properties could potentially arise that do not physically occur in a real process.For example, if the R values ​​of a material are arbitrarily varied at 0, 45, and 90 degrees to the rolling direction and these values ​​are used to calibrate a yield locus, it is possible that a model of the material's anisotropy will result that does not occur in real rolling processes. To account for this, the variance of the semi-finished product properties can be limited to certain ranges.

[0033] Alternatively, it is also possible to characterize at least one batch of blanks, or in particular, several batches, using laboratory tests and to derive a model of the semi-finished product properties, particularly the elastoplastic and tribological properties, from these results. This ensures that the respective model reflects the physical behavior of a batch. However, this approach generally results in higher costs for modeling the fluctuations in the semi-finished product properties, and compared to the sampling approach, it can also be assumed that fewer variants can be considered.

[0034] In addition to the fluctuation in semi-finished product properties, the influence of process parameters on material flow should also be considered. Examples of this include the selection of the forces of the displacement cylinders or the additional application of lubricant. Process parameters are variables that are changed, particularly on the processing equipment, to influence the quality of the produced components. There is usually also a relationship between the process parameters and the material flow. This makes it possible to vary not only the semi-finished product properties but also relevant process parameters in order to find zones of greatest variance in the material flow.

[0035] In order to take the effect of these parameters into account, it is also conceivable to introduce sampling of the parameters. However, the definition range of the individual parameters must be taken into account. This definition range specifies the limits within which the respective value may be selected. If necessary, only discrete values ​​may be used. In this case, it can be advantageous to define a set of permissible values. Consequently, in this case, only values ​​contained in this set may be used to vary the process parameters. Ideally, the effects of varying the semi-finished product properties and the process parameters are not considered separately, but the simulation variants are generated by simultaneously varying both of the aforementioned groups of variables (semi-finished product properties, process parameters).

[0036] Regardless of which approach is chosen for modeling the fluctuation in the semi-finished product properties and how the variation in process parameters is taken into account, as already described, a simulation can be carried out for each simulation variant, i.e. for each simulated machining process with each simulation blank. An FE mesh that describes the respective drawn part can be exported from each simulation variant. In this case, it can be provided that the simulation of the machining processes is carried out based on a mesh having a large number of nodes, wherein the at least one detection point is determined based on a node position, in particular based on a distance of the node position to a center of gravity position of a large number of node positions of nodes of different simulated machining processes.In particular, the same node number can always be considered in different simulations, so that the change in the different simulations can always be related to the same node. In this case, the previously described sword point positions are calculated from the individual positions of the nodes with the same node number in the different simulation variants.

[0037] Shell elements are typically used in forming simulations. The aforementioned FE mesh often describes the midplane of these elements. Alternatively, solid elements can also be used. The resulting FE mesh can also be exported and further processed as described below. In principle, each simulation variant should be tested using suitable models to determine whether tensile instabilities or ductile fractures are to be expected. If material failure is predicted, the result of this simulation variant should be critically examined with regard to its suitability for determining the variance of the material flow.

[0038] In the following, it is assumed that the topology of the FE meshes of all simulation variants is identical. This is ensured, for example, by not performing adaptive refinement of the meshes during the forming simulation. This can be achieved, for example, by starting with the finest possible mesh so that no further refinement of the mesh is necessary. Alternatively, refinement of the mesh can be permitted, whereby the individual nodes or node positions can be back-calculated. The description is transferable accordingly. Under the condition of back-calculated node positions or identical node positions, the coordinates of an individual node from the different simulation variants can be directly compared with each other, or the variance of the node positions of these nodes can be used as a measure of the variance of the material flow.

[0039] This can be performed for all nodes of an FE mesh. Each node has a unique identification number, often referred to as a node number. Using the identification number, the coordinates of an individual node can be extracted from the calculated simulation variants. After extracting the coordinates of an individual node from all FE meshes of the respective simulation variants, these can be combined into a point cloud. The variance of the material flow could, for example, be determined by determining the distance of all these points from the center of gravity of the point cloud. This step is performed for all nodes of the FE mesh.

[0040] This variance is a scalar quantity that can subsequently be visualized on one of the FE meshes created from one of the simulation variants. This scalar quantity can also be used for automatic analysis of the material flow. In this context, it is also possible to color the surface of one of the FE meshes during visualization depending on the variance. The visualization can, for example, be output on a display device of a processing device. FE meshes for this application typically contain several million nodes. Based on these results, suitable positions for measuring the material flow can be determined automatically or visually, as described previously. As already mentioned, these would be detection points that exhibit a particularly large variance in the material flow.As described, the method can also be used when performing adaptive refinement of the FE mesh modeling the blank or semi-finished product. In this case, additional nodes may need to be introduced into the FE mesh. However, it is important to ensure that the identification numbers are unique in all FE meshes of all simulation variants.

[0041] In the next step, these locations are transformed into the coordinate system of the material flow measurement system. Finally, the system can automatically adopt these detection points, or detection points can be manually selected in the measurement system that are close to the detection points that, according to the simulation prediction, exhibit a particularly large material flow variance. It is advantageous to ensure that the selected measurement points are located on the edge of the drawn part or on a leading or trailing edge.

[0042] This procedure allows the material flow to be determined particularly advantageously, and these results can then be used as input variables for process control or for suggesting suitable process parameters in order to achieve the desired quality of the produced components despite fluctuating semi-finished product properties.

[0043] In addition to the described method, the invention relates to a determination device for determining at least one detection point, in particular a plurality of detection points, for detecting the material flow on a blank in a machining process, in particular a forming process, wherein the determination device is designed to carry out the steps:

[0044] Simulating a first machining process of a first simulation board having a first set of semi-finished product properties;

[0045] Simulation of at least one second machining process of at least one second simulation board, in particular of a simulation set comprising a plurality of machining processes of a plurality of different simulation boards, which second simulation board has a second set of semi-finished product properties, wherein at least one process parameter and / or at least one process state of the first machining process is different from at least one similar process parameter and / or process state of the at least one second machining process and / or at least one semi-finished product property of the second set of semi-finished product properties is different from at least one similar semi-finished product property of the first set of semi-finished product properties;

[0046] Determination of the material flow of the blanks in the simulated machining processes;

[0047] Determination of a variance of the material flow between the simulated machining processes;

[0048] Determining the at least one detection point based on the determined material flow and / or the determined variance of the material flow.

[0049] The described determination device is particularly designed to carry out the method described above. The detection points determined by means of the method or by means of the determination device can subsequently be used in a method for processing a blank board by measuring the material flow at the determined detection points and using this to control the processing process. In particular, the processing process can be controlled based on the measured material flow at the at least one detection point. The present description is therefore also applicable within the framework of a method for processing at least one blank board or a processing device for processing at least one blank board.

[0050] All advantages, details, embodiments and / or features described with respect to the method for determining at least one detection point are fully transferable to the determination device, the processing device and the method for processing at least one circuit board.

[0051] The invention is explained using an exemplary embodiment with reference to the figure. The figure is a schematic representation and shows a flow chart of a method for determining a detection point for detecting the material flow on a blank in a machining process.

[0052] The figure shows a schematic flow diagram in the form of blocks 1-5. The method can start, for example, in block 1, in which simulation data for the simulation of machining processes, in particular a simulation set, is provided. For example, the simulation set can have different simulation variants of machining processes from different simulation boards. The different machining processes can differ in terms of their process parameters, for example in the settings of the modeled machining device. The simulation boards can differ from one another based on the semi-finished product properties. For example, in a first machining process, the machining of a first simulation board with first semi-finished product properties can be simulated or modeled based on first process parameters.In a second machining process, the machining of a second simulation blank with second semi-finished product properties can be simulated based on second process parameters. The number of machining processes and the number of simulation blanks can be freely selected. For each simulated machining process, a large number of different simulation blanks can be simulated, and vice versa. For example, the different process parameters can be obtained by varying real process parameters. The different sets of semi-finished product properties can be obtained accordingly by varying a starting value or a fixed starting set of semi-finished product properties.For example, different properties of the semi-finished product, such as a lubricant quantity, sheet thickness, mechanical properties, geometric properties, physical properties, chemical properties, and the like, can be changed. Furthermore, it is possible to determine the various simulation blanks, in particular their semi-finished product properties, based on at least one batch of real blanks. In other words, a specific number of real blanks can be measured to determine the semi-finished product properties. Since the real blanks will differ from one another, at least slightly, with regard to their semi-finished product properties, deviations or variations, and thus individual sets of semi-finished product properties, can be determined for the different simulation blanks.

[0053] The individual simulation variants, i.e. the different simulated machining processes and different simulation blanks, represent the execution of real machining processes on real blanks as a model. In Block 2, the material flow can be determined for each of the simulations carried out in Block 1, in particular at each point or node of the model, e.g. an FE model or FE mesh. In other words, the simulation contains nodes that move or deform as a result of the machining processes, just as the spatial points in the blank would during the machining process. Across the individual simulation variants, the variance of the material flow between the individual simulated machining processes can be determined in Block 2. In other words, for each node, it can be determined how the material flow changes at this point between the different simulation variants.This is a measure of the change in material flow for different blanks with different semi-finished product properties or a change in the process parameters.

[0054] In block 3, the number of detection points to be determined in the method is then specified, for example by a user. Furthermore, in block 3 it can be specified in which area the detection points are to be determined or the areas in which detection points can be determined can be limited. Specifically, in block 3 it is specified that such characteristic areas are the edge of the drawn part that is produced from the blank by machining. Furthermore, lead edges and trailing edges can be selected as characteristic areas in which the detection points are to be determined. Furthermore, it is possible to define at least one exclusion area in block 3 in which the node points are excluded, i.e. that these cannot be determined as detection points regardless of their material flow or the variance of the material flow.

[0055] Subsequently, in block 4, a first detection point is determined. For this purpose, the node of the simulated processes is selected that exhibits the highest variance and, optionally, that exhibits a specific material flow, namely above a defined minimum material flow. This prevents the selection of a detection point that exhibits a high material flow variance but a very low absolute material flow value. Subsequently, further detection points can be determined, for example, the detection points with the next highest variance, until the specified number of detection points has been determined, for example, per specified area.

[0056] Optionally, it is shown that an iterative selection of the detection points can be carried out in block 5 by restricting the available or remaining potential detection points. For example, it can be ensured that there is a minimum distance between the determined detection points. To do this, for the first or generally a preceding - or every - determined detection point, a minimum distance range is defined around the detection point or node, in which all other detection points or nodes are excluded. This means that when branching from block 5 to block 4, the next detection point can be determined as the detection point that has the highest variance of the material flow above the minimum material flow and that is at least the minimum distance away from the predetermined and all other detection points.

[0057] Furthermore, in Block 5, it can be taken into account that each detection point to be determined correlates with the already determined detection points with regard to the material flow by less than a maximum correlation value. For example, this prevents a situation in which several detection points with high variance in the material flow are determined, but these are strongly correlated, making the measurement of the material flow at the different detection points redundant. For example, in Block 5, a correlation analysis is carried out to exclude strongly correlated detection points, namely detection points correlating above the correlation value. In other words, in Block 4, the detection point with the highest variance in the material flow is iteratively determined or selected across the simulation variants, which remains in the remaining set of potential detection points.This results in a restriction of the potentially available detection points in block 5, from which the detection point with the highest variance can be selected in block 4.

[0058] The method can be carried out until the desired or specified number of detection points, in particular per area, has been determined. The detection points can, for example, be output visually, in particular using an FE mesh or a simulation mesh, specifically a mesh that was determined in the simulation. By outputting the detection points, it can be directly shown, for example to a plant operator, where in the real series process or production process the material flow on the drawn part produced from the blank is to be measured in order to use the material flow to characterize the machining process. In particular, the machining process can be controlled based on the material flow measured in this way. For example, at least one process parameter of the machining device can be adjusted based on the measured material flow.

[0059] The described method can be carried out, in particular, by means of a determination device. All advantages, details, and features described with reference to the method are fully applicable to the determination device. As described, the determined detection points for detecting the material flow can be used in a method for detecting the material flow. In particular, a machining process for machining blanks can be controlled based on the detection of the material flow at the at least one determined detection point. The preceding description is therefore also applicable to such a method for machining blanks or a blank machining device in which the machining process is controlled based on the detected material flow at the at least one determined detection point.

[0060] LIST OF REFERENCE SYMBOLS

[0061] 1-5 blocks

Claims

CLAIMS 1. Method for determining at least one detection point, in particular a plurality of detection points, for detecting the material flow on a blank in a machining process, in particular a forming process, characterized by Simulating a first machining process of a first simulation board having a first set of semi-finished product properties; Simulation of at least one second machining process of at least one second simulation board, in particular of a simulation set comprising a plurality of machining processes of a plurality of different simulation boards, which second simulation board has a second set of semi-finished product properties, wherein at least one process parameter and / or at least one process state of the first machining process is different from at least one similar process parameter and / or process state of the at least one second machining process and / or at least one semi-finished product property of the second set of semi-finished product properties is different from at least one similar semi-finished product property of the first set of semi-finished product properties; Determination of the material flow of the blanks in the simulated machining processes; Determination of a variance of the material flow between the simulated machining processes; Determining the at least one detection point based on the determined material flow and / or the determined variance of the material flow.

2. Method according to claim 1, characterized in that a minimum material flow is determined, wherein in the determination of the material flow only potential detection points are determined at which a material flow above the minimum material flow occurs in the simulation.

3. Method according to claim 1 or 2, characterized in that the determination of the detection point is based on at least one characteristic area of the boards, in particular an edge and / or a starting edge and / or a trailing edge and / or a position of a pulling aid of a tool in the machining process, wherein the at least one detection point is determined within the at least one characteristic region.

4. Method according to one of the preceding claims, characterized in that at least two detection points, in particular a defined number of detection points, are determined, wherein the at least two detection points have a minimum distance from one another.

5. Method according to one of the preceding claims, characterized in that a defined number of detection points is determined, in particular by a user.

6. Method according to one of the preceding claims, characterized in that at least one detection point is excluded which correlates with at least one already determined detection point above a defined correlation value related to the material flow.

7. Method according to one of the preceding claims, characterized in that a defined number of detection points is determined iteratively.

8. Method according to one of the preceding claims, characterized in that the sets of semi-finished product properties are determined based on a variance of a starting set, in particular comprising a lubricant quantity and / or an elasto-plastic property and / or a tribological property, and / or based on a recording of sets of semi-finished product properties of at least one batch of real blanks.

9. Method according to one of the preceding claims, characterized in that the simulation of the machining processes is carried out based on a network having a plurality of nodes, wherein the at least one detection point is determined based on a node position, in particular based on a distance of the node position to a Center of gravity position of a variety of node positions of nodes of different simulated machining processes.

10. Determination device for determining at least one detection point, in particular a plurality of detection points, for detecting the material flow on a blank in a machining process, in particular a forming process, characterized in that the determination device is designed to carry out the steps: Simulating a first machining process of a first simulation board having a first set of semi-finished product properties; Simulation of at least one second machining process of at least one second simulation board, in particular of a simulation set comprising a plurality of machining processes of a plurality of different simulation boards, which second simulation board has a second set of semi-finished product properties, wherein at least one process parameter and / or at least one process state of the first machining process is different from at least one similar process parameter and / or process state of the at least one second machining process and / or at least one semi-finished product property of the second set of semi-finished product properties is different from at least one similar semi-finished product property of the first set of semi-finished product properties; Determination of the material flow of the blanks in the simulated machining processes; Determination of a variance of the material flow between the simulated machining processes; Determining the at least one detection point based on the determined material flow and / or the determined variance of the material flow.

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