JP4660637B2 - Press molding system - Google Patents

Description

  The present invention relates to a press molding system. More specifically, the present invention relates to a press molding system that allows simple and quick press molding under optimum molding conditions.

  Conventionally, press-molded plate materials (hereinafter referred to as molded plate materials) have been used in various industries. If the molding conditions are not appropriate for this molded plate material, cracks, wrinkles and the like occur during press molding. The search for the appropriate molding conditions has heretofore been made based on the intuition of experts and trial and error.

  However, diversification of products, reduction of lead time for new product development, introduction of difficult-to-form materials such as ultra-high-strength steel sheets, reduction of the number of processes in multi-stage pressing from the viewpoint of cost reduction, dimensional accuracy required for forming plate materials Due to reasons such as higher accuracy, there are many scenes that cannot be dealt with by the conventional methods described above.

  For example, a high-strength steel sheet has an extremely small amount of elongation, and cracks are more likely to occur during press forming than conventional mild steel sheets. For this reason, it is necessary to repeatedly adjust the shape of the press mold to adjust the mold in order to achieve molding conditions that do not cause problems.

  Further, from the viewpoint of cost reduction, in multi-stage drawing, reduction of the number of steps and substitution of an inexpensive steel sheet with poor formability are required, and the difficulty of press forming is increasing.

  Therefore, in recent years, mainly in the automobile manufacturing industry, by predicting the molding result under the set molding conditions by computer simulation, molding conditions for obtaining a desired molding result without actually creating a mold or the like can be set. It is required to search (see Patent Documents 1 and 2).

However, the conventional computer simulation only outputs the simulation result under arbitrarily set conditions. The operator adjusts the molding conditions by trial and error based on his own experience and intuition. It is necessary to repeat the simulation using the determined molding conditions. For this reason, there is a problem that the optimum molding conditions cannot be searched quickly and the request for shortening the lead time for new product development cannot be sufficiently met.
JP-A-11-319971 JP 2004-42098 A

  The present invention has been made in view of the problems of the prior art, and provides a press molding system that can sufficiently meet the demand for shortening the lead time of new product development using press molded products. It is aimed.

The press molding system of the present invention is a press molding system including an optimum condition searching unit and an optimization processing unit that optimizes the press molding process so as to obtain the optimum molding condition searched by the optimum condition searching unit. And
The optimal condition search unit includes an optimization calculation condition setting unit, an optimization calculation unit, and an optimal solution output unit,
The optimization calculation condition setting unit includes a design variable setting unit, an objective function setting unit, and a constraint condition setting unit.
The design variable setting unit is configured to be able to specify a predetermined parameter as a design variable for molding conditions used in plate press molding,
The objective function setting unit is configured to set one of predetermined parameters as an objective function for a design target used in plate press molding,
The constraint condition setting unit is configured so that a predefined parameter can be designated as a constraint condition for a constraint condition used in plate press molding,
The optimization calculation unit includes optimization calculation execution means, molding simulation means, simulation execution file creation means, and simulation response file creation means ,
The optimization calculation execution means has a selectable program based on various optimization algorithms,
The optimization calculation execution means evaluates a simulation result by the molding simulation means for the designated design variable by a selected program, and determines a search direction of the design variable based on the evaluation result. The design variable is adjusted in the direction .

In press forming system of the present invention, so that the design variables setting unit has a display means for displaying a screen for specifying the parameter, specifies the same parameters by the screen displayed by the display means is made It is preferable to be made.

In the press-forming system of the present invention, the objective function setting unit has a display means for displaying a screen for setting the parameters, setting the parameters is performed by the screen displayed by the display means It is preferable that it is made to be made.

Furthermore, in the press-forming system of the present invention, the constraint condition setting unit has a display means for displaying a screen for specifying the parameter, specifies the same parameters is performed by the screen displayed by the display means It is preferable that it is made to be made.

  Further, in the press molding system of the present invention, it is preferable that the design variable is a bead, and the optimum solution is searched by deforming or moving the initial bead.

Further, in the press molding system of the present invention, it is preferable that the bead is an equivalent draw bead displayed by a single parameter of drawing resistance by the bead .

  Furthermore, in the press molding system of the present invention, it is preferable that the objective function is the maximum sheet thickness, the constraint condition is the minimum sheet thickness, and the search is performed so as to minimize the maximum sheet thickness.

  Furthermore, in the press molding system of the present invention, it is preferable that the design variable is a trim line, and the trim line is changed by morphing a trim mesh having a function of cutting a blank.

  Furthermore, in the press molding system of the present invention, it is preferable that the morphing is performed by changing a weight value for the basic shape of the trim mesh.

Furthermore, in the press-forming system of the present invention, evaluation by the optimization calculation execution means is made to break risk, evaluation of the fracture risk is preferably done by thickness or forming limit diagram.

  According to the present invention, since the optimum press molding conditions are searched in a short time, an excellent effect of shortening the lead time for new product development using the press molded product can be obtained.

  Hereinafter, although the present invention is explained based on an embodiment, referring to an accompanying drawing, the present invention is not limited only to this embodiment.

  A plate press forming system according to an embodiment of the present invention is shown in a block diagram in FIG.

  As shown in FIG. 1, the press molding system P includes an optimum condition search unit S and an optimization processing unit T that optimizes the press molding process so that the optimum molding condition searched by the optimum condition search unit S is obtained. It is supposed to be.

  As shown in FIG. 2, the optimum condition search unit S includes an optimization calculation condition setting unit 1, an optimization calculation unit 2, and an optimum solution output unit 3.

  For example, as shown in FIG. 3, the optimum condition search unit S includes a CPU (Central Processing Unit) 11, a memory 12, an input device 13 such as a keyboard and a mouse, and an output such as a display device and a printer. The computer 10 includes a device 14 and an auxiliary storage device 15 such as a hard disk drive. When the CPU 11 executes a corresponding program, the optimization calculation condition setting unit 1, the optimization calculation unit 2, and the optimization Each function of the solution output unit 3 is realized.

  As shown in FIG. 4, the optimization calculation condition setting unit 1 includes a design variable setting unit 21, an objective function setting unit 22, and a constraint condition setting unit 23.

The design variable setting unit 21 has one or several parameters x _i (i: i = 1, 2,..., N) defined in advance for each of typical forming conditions frequently used in plate press forming. ) As a design variable by the operator, and a program module having a function of supporting the operator to appropriately set the upper limit value and the lower limit value of the design variable.

Here, the parameter x _i, as can be optimized each molding condition as a design variable of the so-called optimization algorithm, is assumed to be defined in advance in correspondence to each of the typical molding conditions. In addition, as shown in FIG. 2, such representative molding conditions include a blank outer shape, a die shape, a wrinkle holding force, a bead (hereinafter also referred to as a draw bead) position and shape, There are friction coefficient, physical property values of each material, molding speed, and the like.

Further, the design variable setting unit 21, an operator display unit that displays such a design variable x _i input easy to be made in various settings screens U (see FIG. 6), for example a GUI as (graphical user interface) It has a function. The display means has a function of displaying a design variant shapes within the upper and lower limits of the variable x _i, for example, or by scaling and rotation, results or moved. The same applies to the following display means.

The objective function setting unit 22 causes the operator to designate one of several predefined parameters F ₀ (x) as an objective function for each typical design target frequently used in plate press forming. And a program module having a function for assisting the operator to appropriately set the evaluation target range.

Here, the parameter F ₀ (x) is defined in advance corresponding to each of the representative design targets so that the optimum solution can be searched by the optimization algorithm by evaluating the response of the simulation under a predetermined molding condition. It is supposed to be done. In addition, as shown in FIG. 2, such representative design goals include an evaluation of the disposal area, an evaluation of the amount of penetration of the outer shape of the molded product, an evaluation of the minimum plate thickness, an evaluation of the presence or absence of cracks, and a risk of breakage. Evaluation of the difference from the ideal shape, evaluation of the presence or absence of wrinkles, evaluation of the molding load, and the like.

The objective function setting unit 22 has a function as display means, for example, a GUI for displaying various setting screens so that the operator can easily input the objective function F ₀ (x).

The constraint condition setting unit 23 sets one or several kinds of parameters F _j (x) for each of typical constraint conditions frequently used in plate press forming, that is, conditions to be observed when achieving a predetermined design goal. This is a program module having a function for assisting the operator to specify the constraint value and to set the condition value appropriately by the operator. Here, the parameter F _j (x) is defined in advance corresponding to each of the representative constraint conditions so that a simulation response under a predetermined molding condition can be evaluated and an optimum solution can be searched by an optimization algorithm. It is supposed to be done. In addition, as shown in FIG. 2, such typical constraint conditions include evaluation of the disposal area, evaluation of the amount of intrusion of the outer shape of the molded product, evaluation of the minimum plate thickness, evaluation of the presence or absence of cracks, risk of fracture Evaluation of the difference from the ideal shape, evaluation of the presence or absence of wrinkles, evaluation of the molding load, and the like.

Further, the constraint condition setting unit 23 has a function as display means, for example, a GUI, for displaying various setting screens so that the operator can easily input the constraint condition F _j (x).

  Hereinafter, the function of each unit of the optimum condition search unit S will be described by taking as an example the case of optimizing the arrangement and shape of the beads.

  As shown in FIG. 5, the bead is a protrusion provided on the die face in order to suppress an excessive flow of a material leading to generation of wrinkles into the mold. That is, in order to prevent wrinkles, it is necessary to give an appropriate stretch to the blank, and the drawing resistance is increased by the bead while applying an appropriate wrinkle holding pressure with the blank holder, thereby holding the blank. At this time, insufficient pulling resistance cannot prevent wrinkling, but if the resistance is too high, the blank breaks.

  For this reason, the necessity for making the arrangement and shape of the beads appropriate is high. When finding an appropriate bead arrangement and shape by computer simulation using an optimization algorithm, it is not well known, but the bead arrangement and shape are set as optimization target molding conditions (design variables) to generate wrinkles. Set as a design goal (objective function) to prevent the occurrence of wrinkles or to reduce the probability of wrinkles as much as possible, and to achieve the design goal, do not cause breakage in the middle of molding, or have a predetermined strength as a molded product A method is conceivable in which the minimum value of the plate thickness for maintaining the thickness is set as a condition (constraint condition) to be kept to be a predetermined value or more.

  However, when trying to incorporate complex elements such as bead layout and shape into the optimization framework based on computer simulation as design variables, it is necessary to optimize near-infinite combinations using highly flexible data called shape data. Thus, it is impossible to obtain an optimal solution within a practical time.

  Therefore, as shown in FIG. 6, the design variable setting unit 21 causes the operator to temporarily place a bead (hereinafter referred to as an initial bead) on the setting screen U based on the experience value. ) 31 is drawn over the die face corresponding part 32, the mode of deformation is designated, and a reasonable deformation range (the rational meaning will be described later), that is, when the deformation is variable magnification Upper / lower limit values of enlargement / reduction ratio, upper / lower limit values of rotation angle for rotational movement, maximum length of movement direction for parallel movement, upper limit value of pulling resistance per unit length of bead・ Enter each value such as the lower limit. When this input is performed, a bead deformation state corresponding to the input deformation mode, that is, a deformation beat (indicated by a simple line segment in the drawing) is drawn on the screen U (FIG. 6A to FIG. 6). (See (e)), the operator can change the settings as necessary while viewing the displayed image.

In this case, the enlargement / reduction magnification, the rotation angle, the movement amount, and the drawing resistance correspond to the parameter x _i , so that the design variable setting unit 21 sets the design variable to the parameter x _i . It can be represented by one or several types. Therefore, compared with the case where the bead shape itself is used as the design variable x _i (in this case, the coordinates of all the intersections (nodes) of the shape data (mesh) become the design variables x _i to be adjusted), the amount of calculation As a result, the optimal solution can be searched quickly.

Here, the pull-out resistance of the bead actually varies depending on various parameters such as the cross-sectional shape of the bead (projection height, etc.) and the wrinkle holding force of the blank holder. However, since causing an increase in calculation amount and calculated by selecting each parameter individually, it is assumed to use a single parameter called pull-out resistance by the beads is a correspondence between these parameters is known as the design variables x _i . This also allows the draw bead to be represented by a simple straight line or curve (hereinafter referred to as an equivalent draw bead).

  FIG. 6C shows the case where the setting of the upper limit value and the lower limit value of the rotation angle with respect to the initial bead 31 is inappropriate, and the existence range of the bead protrudes from the die face corresponding portion 32. FIG. 6 (d) shows a partially enlarged view of FIG. 6 (c). FIG. 6E shows a case where the operator sets appropriate upper and lower limit values while referring to the setting screen U.

Thus, the operator can set with reference to the screen U, with the exclusion of the design variable x _i improbable, easily forming a set of upper and lower limits of the rational design variable x _i. Therefore, it is possible to prevent the calculation time from being extended due to unnecessary calculation.

Figure 7 shows an example of an operation window for the operator to set the design variables x _i. The operation window 33 is displayed on a display device as the output device 14.

  Next, the objective function setting unit 22 and the constraint condition setting unit 23 will be described.

  When examining the possibility of occurrence of wrinkles by computer simulation, it is usually necessary to visually check the simulation result to determine whether or not wrinkles will occur. Therefore, it is not possible to automatically search for an optimal bead arrangement and shape with a small possibility of wrinkles using an optimization algorithm as it is.

Therefore, the objective function setting unit 22 uses the maximum sheet thickness of the molded product as an objective function F ₀ (x) for wrinkle evaluation based on the knowledge that wrinkles are likely to occur at locations where the sheet thickness increases due to molding. It is supposed to be used. That is, the operator designates the maximum thickness of the molded product as the objective function F ₀ (x) on the predetermined setting screen displayed by the objective function setting unit 22 and minimizes the target (objective function (maximum thickness)). To be set).

In this case, the constraint condition setting unit 23 sets the constraint condition not to cause breakage or to set the minimum thickness to a predetermined value or more. As such a constraint condition F _j (x), for example, the minimum thickness of the molded product may be used, or the strain margin up to the fracture limit in the maximum principal strain direction in FLD (molding limit diagram) is used. It is good.

  Further, the objective function and the constraint function are not necessarily evaluated for the entire molded product, and can be limited to a specific part of the molded product according to the purpose. By performing such a limitation, the initial purpose is achieved while reducing the time required for the search. For example, in press molding, since it is known from experience that it is easy for cracks to occur in the bent portion of the bottom where drawing is performed, the evaluation target region can be limited to the vicinity including the bent portion of the bottom. .

  FIG. 8 shows an evaluation target region in which such a limitation is made in the case where the crack evaluation of the bent portion at the bottom portion is performed using FLD as a constraint function. FIG. 8A shows an inappropriate example in which the bent portion at the bottom to be evaluated is not included in the evaluation target area. As described above, when the region where evaluation is desired is out of the evaluation target region, the evaluation target region is appropriately corrected while viewing the setting screen U so that the bent portion at the bottom is included in the evaluation target region. FIG. 8B shows an example in which such a correction is made so that the bent portion at the bottom is included in the evaluation target region. FIG. 9 shows an example of the operation window 33 for the operator to make such settings for the constraint function.

  Next, the optimization calculation unit 2 will be described.

  The optimization calculation unit 2 includes an optimization calculation execution unit 4, a molding simulation unit 5, a simulation execution file creation unit 6, and a simulation response file creation unit 7.

  The optimization calculation execution means 4 is optimized using optimization calculation programs based on various optimization algorithms such as an algorithm based on the successive approximation response surface method, an algorithm based on the sequential correction method, and an optimization algorithm combined with a high-precision / low-precision analysis model. An interface having a function of causing the CPU 11 to execute a process for searching for a solution, and allowing an operator to designate an optimization calculation program based on which optimization algorithm to search for an optimal solution among the optimization algorithms. Including.

For example, in some simulations, detailed analysis is indispensable, and in such a case, the calculation time becomes very long. For this reason, when an optimization calculation program using an optimization algorithm such as a successive approximation response surface method that requires simulation to be repeated several tens of times is applied to such a simulation, an optimal solution may not be obtained within a practical time. . Therefore, in such a case, the operator, optimization relatively simple optimization algorithms, such as successive correction method capable of repeatedly reducing the number of calculations by the modification of the design variable x _i with the result of decision operator intervention A calculation program is selected and used for optimization. This makes it possible to obtain an optimal solution within a practical time.

  In addition, the operator selects an optimization calculation program based on the optimization algorithm combined with the high-precision / low-precision analysis model, so that a high-precision model with high accuracy but a long calculation time and a low-precision but low calculation time are obtained. The optimal solution is searched mainly using the tuned low accuracy model while using the accuracy model together and tuning the low accuracy model according to the result of the high accuracy model. Thereby, optimization can be performed in a short time.

Thus, optimization calculation executing means 4, the optimization calculation program based on the selected optimization algorithm, the objective function F ₀ (x) and constraints is the response of the forming simulation means 5 with respect to the design variables x _i that are set The condition F _j (x) is evaluated, the search direction of the design variable x _i is determined based on the evaluation result, the value of the design variable x _i is adjusted in the determined search direction, and the design variable x _i whose value is adjusted is used. The optimum design variable x _i is searched for in such a procedure that the design variable x _i is output to the forming simulation means 5 via the simulation execution file creation means 6 so as to execute the simulation again.

  The molding simulation means 5 is provided with plate press molding analysis software (also referred to as a solver), and uses the shape data of the blank to be molded and its physical property value data, and press molding is performed with a set mold. It has a function of predicting the molding result by simulation and outputting it. Examples of plate press forming analysis software include PAM-STAMP, QUIK-STAMP, and LS-DYNA.

The simulation execution file creation means 6 uses the design variable x _i instructed by the optimization calculation execution means 4 so that the molding simulation means 5 can execute the simulation so that the design variable x output by the optimization calculation execution means 4 can be executed. _It has a function of automatically creating a predetermined simulation execution file based on _i .

For example, the simulation execution file creation means 6, the shape of the equivalent drawbead fix the forming simulation means 5 is executable form in accordance with the design variable x _i, it writes it to the simulation executable to forming simulation means 5 Send out or create a morphing trim mesh by deforming the basic trim mesh according to the design variable x _i1 (weight), and move, rotate, enlarge / reduce the morphing trim mesh according to the design variable x _i2 After the trim mesh is created, the blank is cut at the overlapping portion, and the blank after the cut is modified into a format that can be executed by the molding simulation means 5 and written into a simulation execution file, which is then sent to the molding simulation means 5 To do. The weight and trim mesh will be described later.

The simulation response file creation means 7 automatically calculates the objective function F ₀ (x) and the constraint condition F _j (x) based on the simulation result by the molding simulation means 5 and is optimal as a response to the designated design variable x _i . It has a function of outputting to the calculation calculation execution means 4.

  As described above, various types of plate press forming analysis software are commercially available, and can be applied to various software by appropriately adjusting the simulation execution file creation means 6 and the simulation response file creation means 7. Is possible.

Hereinafter, the operation of the optimum condition search unit S will be described with reference to the flowcharts of FIGS. 10 and 11 by taking as an example the case of optimizing the arrangement and shape of the beads. Figure 10 is a flowchart of setting processing of the design variable _{x i} to design variable setting unit 21 to be executed by the CPU 11. The following steps are executed after selecting the item “bead optimization” from a plurality of prescribed molding condition optimizations. In the figure, S1 to S7 indicate step numbers.

  Step S1: An initial bead is set.

Step S2: The deformation mode (movement, rotation, enlargement / reduction) of the initial bead is set. Incidentally, the procedure of step S1, S2, the design variables _{x i} are set.

  Step S3: Necessary specifications are set according to the mode of deformation (movement direction in the case of movement, reference point in the case of enlargement / reduction, rotation center in the case of rotation).

Step S4: To set the range of the design variable x _i (upper and lower limit values of the movement amount, the rotation angle and scaling factor).

  Step S5: The operator can visually check whether the setting contents in Steps S1 to S4 are reasonable, such as displaying the initial bead and the existence range of the beads by deformation from the upper limit to the lower limit (see FIG. 6). Thus, the display based on the setting content is performed on the setting screen U.

  FIG. 12 shows an example of such display. In FIG. 5A, when the initial bead B1 is displayed at a predetermined position on the die face near the product shape corresponding portion W1 of the die, and the deformation is a horizontal translation in the figure, the deformation range (movement amount) is the operator. Shows a case where the bead existence range is set without being overlapped with the product shape corresponding portion W1 of the die. In FIG. 5B, when the initial bead B2 is displayed at a predetermined position on the die face near the product shape corresponding portion W2 of the die, and the deformation is a rotational movement around the point C1, the deformation range (rotation angle) is The case where it is set rationally by the operator is shown. In FIG. 8C, when the initial bead B3 is displayed at a predetermined position on the die face near the product shape corresponding portion W3 of the die, and the deformation is the enlargement / reduction in the vertical direction in the figure, the deformation range (magnification) is the operator. The case where it is set rationally by is shown.

  Step S6: If there is a defect according to the result of confirming whether or not the setting has a defect by displaying the setting screen, the process returns to step S4, and if there is no defect, the process proceeds to step S7. For example, the operator checks whether the existence range of the beads protrudes from the part corresponding to the molded product. If there is a defect, the operator reviews the set value.

  Step S7: The initial value of the bead pulling resistance and its upper and lower limit values are set.

  FIG. 11 is a flowchart of a procedure relating to processing by the simulation execution file creation means 6 and processing by the molding simulation means 5. During each of the following steps, steps S11 to S14 are executed by the simulation execution file creation means 6, and step S15 is executed by the molding simulation means 5. In the figure, S11 to S15 indicate step numbers.

  Step S11: A simulation execution file is read from the memory 12.

Step S12: Based on the output by the design variable x _i of the optimization calculation execution means 4, moving the initial drawbead, rotation, expansion and shrinking, to create a drawbead subject to this simulation.

  Step S13: The created draw bead is projected onto the die face surface.

Step S14: To set in accordance with the design variable x _i the pull-out resistance by drawbead. As a result, it is possible to accurately execute a simulation using a draw bead expressed as a simple curve as an equivalent draw bead. The obtained equivalent draw bead is changed to a format that can be simulated by the molding simulation means 5 and written into the simulation execution file. This simulation execution file is sent to the molding simulation means 5.

  Step S15: The simulation is executed, and a file representing the result is output to the simulation response file creating means 7.

  FIG. 13 shows a case where the arrangement and shape of the two beads B11 and B12 are optimized.

Here, as shown in FIG. 6A, the rotation angles and pull-out resistances of the beads (initial beads) B11 and B12 are set as design variables x ₁ , x ₂ , and x ₃ . FIG. 5B shows the simulation result for a predetermined setting variable. Here, the constraint condition (minimum plate thickness) is 0.7 mm or more, the objective function is the maximum plate thickness, and the target is to minimize the objective function (maximum plate thickness). FIG. 3C shows a setting example and optimum solution for the design variables x ₁ , x ₂ , and x ₃ in a table.

  FIG. 14 shows another example in which the arrangement and shape of two beads are optimized. The figure (a) shows the initial bead (initial value) and the optimum bead corresponding to the optimum solution, and the figure (b) shows the respective responses (objective function (maximum thickness), constraint condition (minimum thickness)). ). From the table, it is understood that the maximum plate thickness is reduced from 1.854 mm to 1.598 mm, and the minimum plate thickness satisfies the constraint condition.

  FIG. 15 shows a simulation result in the example of FIG. FIG. 4A shows the simulation result of the initial bead (initial value), and FIG. 4B shows the simulation result of the optimum solution. Here, both the minimum and maximum plate thicknesses are improved. FIG. 14C is the same diagram as FIG.

  Next, the operation of the optimum condition search unit S will be described with reference to FIGS. 16 to 23, taking as an example the case where the blank shape is optimized.

  It is natural that a blank shape cannot be obtained in a desired shape unless it is appropriate, and it causes wrinkles and breakage. High importance.

When a blank shape is optimized using an optimization algorithm, it is practically impossible to perform optimization calculation using the shape itself as a design variable x _i , so what parameters are set as the design variable x _i Is the key.

Although it is not publicly known, the basic blank shape is set, and the range of deformation is set for the part where wrinkles etc. are likely to occur, and the change ratio between the innermost outline and the outermost outline in and to represent a blank shape, a method of performing optimization calculation the change rate as a design variable x _i is considered.

  However, in this method, as shown in FIGS. 16A and 16C, the shape of the basic blank W2 (see FIG. 16A) needs to be deformed by morphing. That is, it is necessary to adjust the blank shape by extending or compressing the distance between the eyes of the blank-shaped mesh. However, if the mesh interval is changed in this way, elements with extremely different aspect ratios or twisted elements are generated, and the calculation time may be extremely increased, or accurate simulation may not be possible.

Thus, in the embodiment, instead of the rate of change of changing the shape of the blank itself and the design variable x _i, as shown in FIG. 16 (a) and (b), the local contour morphing trim mesh blank W2 shall trim lines L1, deformation ratio of morphing trim mesh, that is assumed to perform optimization calculation deformation rate of the local contour line L1 as a design variable x _i. The morphing trim mesh will be described later.

  Specifically, as shown in FIGS. 17 and 18, a trim mesh T3 for cutting an extra portion with respect to the blank W3 is considered. As shown in FIG. 17A, the trim mesh T3 is arranged in the vicinity of the blank W3 on the setting screen U, and is configured as a shape changing tool having a function of cutting a portion overlapping the blank W3 from the blank W3. . Therefore, by modifying the trim mesh T3 (by morphing), the trim line L3 is changed, and the shape of the blank W3 can be adjusted. Moreover, by doing in this way, even if the elements constituting the trim mesh T3 are twisted, since only the trim line L3 is used in the simulation, an accurate simulation can be performed.

That is, the basic shape (minimum shape, see FIG. 17B) and the limit shape (see FIG. 18C) of the trim mesh T3 are set, the weight of the basic shape is “0”, and the weight of the limit shape is The value “1” is set, and the weight x _i (0 ≦ x _i ≦ 1) is used as a design variable to represent the shape of the trim mesh T3, that is, the shape of the trim line L3 or the blank W3. Thus, the shape of the blank W3 regardless of the morphing itself, since it is possible to adjust in accordance with the design variable x _i, can explore the optimum shape of the blank W3 using an optimization algorithm It becomes possible.

Also in this case, whether the range of the design variable x _i is reasonable, for example, trim line L3 is possible to perform setting while confirming the like or not bite into the molded article the corresponding parts in the setting screen U Become.

  Hereinafter, the operation of the optimum condition search unit S will be described with reference to the flowcharts of FIGS. 19 and 20, taking as an example the case of optimizing the blank shape.

  FIG. 19 shows processing by the design variable setting unit 21. The following steps are executed after selecting the item “blank optimization” from a plurality of prescribed molding condition optimizations. In the figure, S21 to S26 indicate step numbers.

  Step S21: An initial blank shape is set.

  Step S22: A basic trim mesh is set.

Step S23: A trim mesh (limit trim mesh) for cutting the blank to the maximum from the initial blank shape is created by morphing and deforming the basic trim mesh created in step S22. A trim mesh (morphing trim mesh) for cutting a blank is created by appropriately changing a trim mesh between a basic trim mesh and a limit trim mesh. The deformation ratio (weight) is the first design variable x _i.

Step S24: If necessary to make the cut portion of the blank more appropriate, the trim mesh (final trim mesh) to be cut is set by moving, enlarging, reducing, and rotating the morph trim trim mesh. Movement amount or the like at this time is the second design variable x _i. If it is not necessary to move, enlarge, reduce, or rotate the morphing trim mesh, the morphing trim mesh created in step S23 is set as the final trim mesh.

Step S25: final trim mesh when position of the last trim mesh, or shape is not as unreasonable that in order to check the operator, was varied between 0 and 1 each design variable x _i to the setting screen U Is displayed.

  Step S26: If a malfunction is confirmed by the operator, the process returns to step S22, and if there is no malfunction, the process is terminated.

  FIG. 20 is a flowchart of a procedure relating to processing by the simulation execution file creation means 6 and processing by the molding simulation means 5. In the following steps, steps S31 to S34 are executed by the simulation execution file creation means 6, and step S35 is executed by the molding simulation means 5. In the figure, S31 to S35 indicate step numbers. Moreover, the order of step S32 and step S33 may be changed.

  Step S31: A simulation execution file is read from the memory 12.

Step S32: reads the first design variable x _i, that weights the output of the optimization calculation executing means 4, to create a morphing trim mesh by modifying the basic trim mesh based on the weight.

Step S33: reads the second design variable x _i outputted optimization calculation execution means 4, deforming the morphing trim mesh according to the value (amount of movement, etc.), to create a final trim mesh. Thereby, the trim line L3 is determined.

  Step S34: The overlapping portion of the blank and the final trim mesh is cut out from the blank W3. Thereby, a blank shape is adjusted.

  Step S35: A simulation is executed using the blank W3 from which the overlapping portion has been removed, and a file representing the result is output to the simulation response file creation means 7.

FIG. 21 shows an example in which the blank shape is optimized. Here, as shown in FIG. 9A, in the setting screen U, the basic trim mesh (weight = 0) is set, the limit trim mesh (weight = 1) is set, and the weight is set between 0 and 1. appropriately adjusted, the adjusted weight is adjusted blank configuration accordingly is set as the first design variable x _11, blank holding force (BHF) is set as the second design variables x _12. FIG. 5B shows the initial analysis result, where the objective function and its target are set to maximize the minimum plate thickness (to avoid fracture), and the constraint condition is that the maximum plate thickness is equal to or less than a predetermined value. The flange line included in the evaluation target area does not enter the product line. FIG. 4C is a table showing the setting of the design variables x ₁₁ and x ₁₂ and the obtained optimum solutions in this example.

  FIG. 22 shows another example in which the blank shape is optimized. FIG. 5A shows an initial blank, a maximum blank corresponding to the basic trim mesh, a minimum blank corresponding to the limit trim mesh, and an optimal blank corresponding to the optimal solution, that is, the final trim mesh. FIG. 4B shows the entire initial blank and optimum blank. FIG. 4C shows an initial blank (initial value) and an optimal solution response (objective function (maximum thickness) and constraint condition (minimum thickness)) in this example.

  FIG. 23 shows a simulation result (molding result) in another example in which the blank shape is optimized. FIG. 4A shows the simulation result of the initial blank, and FIG. 4B shows the simulation result of the optimum solution. Here, both the minimum thickness (objective function) and the maximum thickness (constraint function) were improved. FIG. 10C is the same diagram as FIG.

  The present invention can be applied to press molding of various plate materials.

It is a block diagram showing the whole press molding system composition concerning one embodiment of the present invention. It is a block diagram which shows the detail of the optimal condition search part of the press molding system. It is a block diagram which shows an example of the hardware constitutions of the optimal condition search part. It is a block diagram which shows the detail of an optimization calculation condition setting part. It is a schematic diagram which shows an example of a press machine. It is a figure which shows the example of a setting of the design variable by a design variable setting part. It is a schematic diagram which shows an example of the operation window for an operator to set a design variable. It is a schematic diagram which shows the limited evaluation object area | region, Comprising: The same (a) shows an example with limitation inappropriate, (b) shows an example with limitation appropriate. It is a schematic diagram which shows an example of the operation window for an operator to set a constraint function. It is a flowchart about the setting process of the design variable by a design variable setting part. It is a flowchart about the process sequence in a simulation execution file preparation means and a shaping | molding simulation part. It is a figure which shows the Example of the display by a design variable setting part. It is a figure which shows the Example which optimized the arrangement | positioning and shape of two beads. It is a figure which shows the other Example which implemented arrangement | positioning and shape optimization of two beads. It is a figure which shows the simulation result in the example of FIG. It is a figure which shows the basic principle for optimizing a blank shape using an optimization algorithm, (a) shows the blank shape used as object, (b) shows the case where it trims with a mesh, (c) shows the case of correcting by morphing. It is a figure which shows the specific setting method for setting a blank shape as a design variable by a design variable setting part. It is a figure which shows the specific setting method for setting a blank shape as a design variable by a design variable setting part. It is a flowchart about the setting process of the design variable by a design variable setting part. It is a flowchart about the process sequence in a simulation execution file preparation means and a shaping | molding simulation part. It is a figure which shows the setting and the optimal solution of the Example which optimized the blank shape using the optimization algorithm. It is a figure which shows the setting and optimal solution of another Example which optimized the blank shape using the optimization algorithm. It is a figure which shows the simulation result in the Example.

Explanation of symbols

P Press forming system S Optimal condition search unit T Optimization processing unit 1 Optimization calculation condition setting unit 2 Optimization calculation unit 3 Optimal solution output unit 4 Optimization calculation execution unit 5 Molding simulation unit 6 Simulation execution file creation unit 7 Simulation response File creation means 21 Design variable setting part 22 Objective function setting part 23 Constraint condition setting part

Claims (10)

A press molding system comprising: an optimal condition search unit; and an optimization processing unit that optimizes the press molding process so as to be the optimal molding condition searched by the optimal condition search unit,
The optimal condition search unit includes an optimization calculation condition setting unit, an optimization calculation unit, and an optimal solution output unit,
The optimization calculation condition setting unit includes a design variable setting unit, an objective function setting unit, and a constraint condition setting unit.
The design variable setting unit is configured to be able to specify a predetermined parameter as a design variable for molding conditions used in plate press molding,
The objective function setting unit is configured to set one of predetermined parameters as an objective function for a design target used in plate press molding,
The constraint condition setting unit is configured so that a predefined parameter can be designated as a constraint condition for a constraint condition used in plate press molding,
The optimization calculation unit includes optimization calculation execution means, molding simulation means, simulation execution file creation means, and simulation response file creation means ,
The optimization calculation execution means has a selectable program based on various optimization algorithms,
The optimization calculation execution means evaluates a simulation result by the molding simulation means for the designated design variable by a selected program, and determines a search direction of the design variable based on the evaluation result. A press molding system characterized in that the design variable is adjusted in a direction . It said design variable setting unit has a display means for displaying a screen for specifying the parameter, characterized by comprising been so specified the parameters is performed by the screen displayed by the display means The press molding system according to claim 1. The objective function setting unit has a display means for displaying a screen for setting the parameter, characterized by comprising been to set the same parameters is performed by the screen displayed by the display means The press molding system according to claim 1. The constraint condition setting unit has a display means for displaying a screen for specifying the parameter, characterized by comprising been so specified the parameters is performed by the screen displayed by the display means The press molding system according to claim 1. 3. The press molding system according to claim 2, wherein the design variable is a bead, and an optimum solution is searched by deforming or moving the initial bead. 6. The press forming system according to claim 5, wherein the bead is an equivalent draw bead displayed by a single parameter of drawing resistance by the bead . 2. The press forming system according to claim 1, wherein the objective function is a maximum sheet thickness, the constraint condition is a minimum sheet thickness, and a search is performed to minimize the maximum sheet thickness. The press forming system according to claim 1, wherein the design variable is a trim line, and the trim line is changed by morphing a trim mesh having a function of cutting a blank. The press forming system according to claim 8, wherein the morphing is performed by changing a weight value for a basic shape of the trim mesh. 2. The press molding system according to claim 1, wherein the optimization calculation execution means is evaluated for the fracture risk, and the fracture risk is evaluated based on a plate thickness or a molding limit diagram.