Method, Apparatus and Program for Determining Construction Data of the Deep-Drawing Tool Geometry by Means of Hybrid Springback Compensation

Abstract

Methods, systems, and devices for determining construction data for producing a forming die are provided. Using an electronic computing device, a simulation is carried out that includes moving die parts of a die toward each other to a closed position, reshaping a workpiece reshaping a workpiece from an initial state to a first deformed state due to the moving of the die parts to the closed position, keeping the die parts at least temporarily in the closed state to maintain the workpiece in the first deformed state, moving the die parts away from each other to an open position, and deforming the workpiece to a second deformed state from the first deformed state due to internal stresses of the workpiece and due to moving of the die parts to the open position. A geometry of a new die part that influences the reshaping is determined.

Claims

1.-11. (canceled)

12. A method for determining design data for producing a forming die provided for reshaping components, comprising: carrying out, using an electronic computing device, a first simulation, comprising: moving die parts of a die toward each other to a closed position, reshaping a workpiece from an initial state to a first deformed state due to the moving of the die parts to the closed position, keeping the die parts at least temporarily in the closed position to maintain the workpiece in the first deformed state, moving the die parts away from each other to an open position, and deforming the workpiece to a second deformed state from the first deformed state due to internal stresses of the workpiece and due to moving of the die parts to the open position; calculating, using the electronic computing device, a stress state that characterizes the internal stresses of the workpiece while in the first deformed state, wherein the deformation of the workpiece in the second deformed state is based on an inversion of the stress state; determining, using the electronic computing device, a geometry of a new die part that influences the reshaping; and carrying out, using the electronic computing device, a second simulation comprising: reshaping the workpiece using the new die part having the geometry from an initial state to a third deformed state, comparing the third deformed state with a target state, calculating a vector field that characterizes a difference between the third deformed state and the target state, and calculating the design data as a function of the geometry and an inversion of the vector field.

13. The method according to claim 12, wherein the reshaping of the workpiece is a deep-drawing of the workpiece.

14. The method according to claim 12, wherein the workpiece is a sheet metal component.

15. The method according to claim 12, further comprising: simulating, using the electronic computing device: a first shape of the workpiece in the first deformed state, and a second shape of the workpiece in the second deformed state, wherein the geometry is calculated using the electronic computing device as a function of the simulated first and second shapes.

16. The method according to claim 15, further comprising: calculating a further vector field characterizing a difference between the first and second simulated shapes is calculated, wherein the geometry is calculated using the electronic computing device as a function of the further vector field.

17. The method according to claim 12, wherein the first simulation is carried out based on a simulation model of the die, wherein the simulation model describes an initial geometry of the die.

18. The method according to claim 17, wherein the initial geometry of the die is changed to a different geometry of the new die part as a function of the second deformed state.

19. The use of a method according to claim 12, wherein the method is used to produce the forming die.

20. An electronic computing device comprising: a processor; and a memory in communication with the processor and storing instructions executable by the processor to configure the electronic computing device to perform the method according to claim 12.

21. A non-transitory computer readable medium comprising instructions operable, when executed by one or more computing systems to configure the one or more computing systems to carry out the method according to claim 12.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0046] FIG. 1 shows a flowchart to illustrate a method according to the present subject matter for determining design data for producing a forming die provided for reshaping components.

DETAILED DESCRIPTION

[0047] A method is described below using which design data are determined, in particular calculated. The design data can be used or are used in order to produce an actually physically existing, physical forming die, which means to design and/or to fabricate the same. In its finished or completely produced state, the forming die has die elements which are also designated as die parts or die halves. The die elements can be moved relative to each other, in particular translationally, and as a result moved toward each other and away from each other. In order, for example, to reshape an actually physically existing, physical component using the forming die, the component is laid in the forming die—while the die parts and thus the forming die are open—consequently arranged between the die parts that have been opened and moved apart from each other here or away from each other. The die parts are then moved toward each other, as a result of which the die parts and thus the forming die are closed, while the component is arranged between the die parts. The fact that the die parts are moved toward each other, consequently closed, means that respective active surfaces of the die parts, also designated as die active surfaces, come into at least indirect, in particular direct, contact with the component, in particular at least with respective partial or wall regions of the component. As a result, the die parts exert external forces, in particular external contact forces, on the component via the active surfaces, as a result of which the component, in particular starting from an original state, is reshaped and, as a result, brought for example into a first deformed state. If the die parts are initially kept closed, then the contact forces continue to act from the die parts on the component, which is thus kept in the first deformed state. In the first deformed state, internal stresses act within the component, wherein the component, despite or counter to the internal stresses, is kept in the first deformed state using the closed die parts. If, then, the die parts are moved away from each other, consequently opened, then the internal stresses can be dissipated, so that the component, starting from the first deformed state, deforms automatically or independently into a second deformed state because of the internal stresses and because of the opening of the die parts. This takes place since, as a result of opening the die parts, external contact forces from the die parts can no longer act on the component. The automatic deformation of the component, starting from the first deformed state and, for example, taking place because of the internal stresses, is also designated as springing up, spring up, springing back, spring back, springing open or elastic springback. As a result of the elastic springback, the component therefore comes into the second deformed state, in which the component, for example, has or assumes a final state and, for example, a final shape or final geometry in the process. The first deformed state is also designated as an initial state, for example, in which the component has or assumes an initial shape or initial geometry, for example. It is desirable here that the final shape or final geometry does not differ or not differ unduly from a desired target shape or target geometry. The method now makes it possible to find such a geometry of the die parts, in particular of the active surfaces, in a time-saving and cost-efficient manner, such that the final shape or final geometry of the component, following the elastic springback, corresponds to the desired target shape or target geometry or at least does not differ unduly from the target shape or target geometry.

[0048] To this end, in a first step S1 of the method, provision is made for a simulation to be carried out using an electronic computing device. In the simulation, it is simulated that die parts of a die are moved toward each other and, as a result, are moved into a closed position. The die used within the context of the simulation is, for example, the aforementioned forming die or a simulation or a simulation model of the forming die so that, for example, the die parts used within the context of the simulation or mentioned with respect to the simulation can be the die parts or simulation models of the die parts of the forming die. In the simulation, it is additionally simulated that, as a result of moving the die parts into the closed position, a workpiece is reshaped and, as a result, is transferred from an initial state into a first deformed state.

[0049] The workpiece mentioned or used within the context of the simulation is thus, for example, the component or a simulation model of the or a physical component. In the simulation, it is additionally simulated that the die parts remain at least temporarily in the closed state and, as a result, keep the workpiece in the first deformed state. In the simulation, it is additionally simulated that the die parts are moved away from each other and, as a result, moved from the closed position into an open position, consequently opened. In the simulation, it is further simulated that, as a result of the movement of the die parts into the open position, starting from the first deformed state, the workpiece deforms automatically into a second deformed state on account of internal stresses of the workpiece that is in the first deformed state.

[0050] In a second step S2 of the method, using the electronic computing device, a stress state is calculated, which characterizes the internal stresses of the workpiece that is held in the first deformed state and, as a result, is in the first deformed state.

[0051] In a third step S3 of the method, using the electronic computing device, the stress state is inverted, in particular mathematically, as a result of which an inverted stress state is calculated from the initially determined actual stress state. The inversion of the stress state, also designated as inversion or stress inversion, comprises, for example, that, in particular all, mathematical signs of the actual stress state are inverted. Thus, for example, positive signs become negative signs and vice versa. In the method, provision is additionally made for the automatic deformation of the workpiece into the second deformed state, consequently the elastic springback, to be simulated on the basis of the inverted stress state.

[0052] In a fourth step S4 of the method, using the electronic computing device and as a function of the second deformed state, a geometry of the forming die influencing the reshaping and also designated as first geometry is determined, in particular calculated.

[0053] For example, respective shapes of the workpiece in the deformed states are calculated. In addition, for example, a first vector field is calculated, which describes a difference between the shape of the workpiece in the first deformed state and the shape of the workpiece in the second deformed state. By using the first vector field, a correction or a correction rule can be determined or the vector field is a correction or correction rule, wherein the correction or correction rule describes such a geometry in the form of the first geometry or such a change of a starting initial geometry of the die into the first geometry of the tool parts such that the first geometry of the die parts resulting from the change in the initial geometry and different from the initial geometry leads to the situation in which, when the component is reshaped using the die parts, following the elastic springback, the component has such a shape which already very closely resembles the desired target shape. In order to compensate for any remaining differences and thus to be able to determine the design data in a particularly time-saving and cost-efficient manner and, as a result, to be able to produce the forming die or its die parts in a particularly time-saving and cost-efficient manner, in a fifth step S5 of the method, a second simulation is carried out using the electronic computing device, in particular after the first simulation. In the second simulation, it is simulated that, starting from the initial state, the workpiece is reshaped using the die having the first geometry and, as a result, is transferred from the initial state into a third deformed state. Preferably, the third deformed state is different from the first deformed state since, preferably, in the first simulation the die had the initial geometry different from the first geometry and, in the first simulation, starting from the initial state, the workpiece is or was reshaped using the die having the initial geometry, wherein, by contrast, in the second simulation the die has the first geometry preferably differing from the initial geometry and, in the second simulation, starting from the initial state, the workpiece is reshaped using the die having the first geometry.

[0054] In a sixth step S6 of the method, the third deformed state is compared with a target state using the electronic computing device. The target state corresponds to the desired target shape, so that the workpiece then has the target state if the workpiece has the target shape. A second vector field, which characterizes a difference between the third deformed state and the target state, is calculated here using the electronic computing device.

[0055] In a seventh step S7 of the method, a path inversion is carried out using the electronic computing device, in which the second vector field is inverted, in particular mathematically. As a result of the inversion of the initially calculated second vector field, an inverted vector field is calculated or determined. In an eighth step S8 of the method, using the electronic computing device, the design data are finally calculated as a function of the first geometry and as a function of the inverted vector field. It should be mentioned at this point that the stress inversion can be carried out exactly once, that is to say performed a single time, consequently once and, in particular, the combination of stress inversion and path inversion is therefore carried out in order to be able to implement the forming die in a time-saving and cost-efficient manner. However, it is entirely conceivable that the path inversion can nevertheless be carried out at least once or repeatedly after that.