JP6741514B2 - Method and apparatus for optimizing press molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method and apparatus for optimizing press molding for determining an optimum press condition and material shape when a molded product is manufactured by press molding a plate material.

For example, when pressing a plate material to manufacture a product with a predetermined shape, a simulation is performed in advance using the finite element method, etc., and the material shape, the number of times of pressing, the mold shape, etc., which does not cause cracks during the press processing, etc. It is common practice to estimate For example, there is a prospective mold shape creating method and apparatus described in Patent Document 1 below.

JP, 2016-020000, A

In the conventional prospective mold shape creating method and apparatus described above, after performing the mold shape creating step, the shape after springback is acquired, and the expected mold quantity for the mold part that contacts the press-formed product is acquired. , The shape of the mold is corrected based on the estimated amount of the mold. However, as a factor that does not cause a crack or the like in the material during press working, it is often not only the mold but also the shape of the material, and optimization of the material shape is required.

The present invention is to solve the above-mentioned problems, and to provide an optimization method and apparatus for press molding that improves the accuracy of a product manufactured by press working and shortens the analysis time in optimizing the shape of a material. With the goal.

The optimization method of the press forming of the present invention to achieve the above object, a temporary material shape setting step of setting a temporary material shape, an analysis model creating step of creating an analysis model of press working, the analysis model A press condition determining step for determining a press condition including a pressing amount and a pressing frequency for the temporary material shape using the material, and a material shape for determining a material shape by a press working analysis considering springback using the analysis model and the pressing condition. And a determining step.

Therefore, by using the analysis model to determine the press conditions consisting of the indentation amount and the number of indentations with respect to the temporary material shape, and by using the analysis model to determine the material shape in consideration of springback, the product manufactured by press working The accuracy of can be improved, and the analysis time for forming the optimum shape of the material can be shortened.

In the method for optimizing press molding of the present invention, a simulation using the analysis model is performed with a predetermined first indentation amount smaller than the maximum indentation amount, a crack is determined based on a preset first cracking criterion, and a crack occurs. If it is determined that the first cracking amount is decreased, the first pushing amount is reduced, the simulation using the analysis model is performed again, and the cracking determination is performed based on the first cracking criterion.

Therefore, the first indentation amount is reduced based on the simulation result using the analysis model based on the simulation result using the analysis model, and if it is determined that the indentation has occurred, the first indentation amount is decreased and the simulation is performed again. By making the determination, the amount of one push can be set to an appropriate amount.

In the method for optimizing press molding of the present invention, a crack is determined by the first crack criteria, and when it is determined that no crack occurs, a second push amount obtained by subtracting the first push amount from the maximum push amount is used. A simulation is performed using the analysis model, and crack determination is performed based on the first crack criteria.

Therefore, if a crack does not occur in the simulation result with the first pushing amount, the pushing amount can be set to an appropriate amount for a plurality of times by setting the second pushing amount and performing the simulation.

The method for optimizing press molding of the present invention is characterized in that after the second indentation amount is set, a simulation for removing the residual strain of the material using the analysis model is performed.

Therefore, by performing a simulation in consideration of the residual strain of the material, highly accurate crack determination can be performed.

In the method for optimizing press molding of the present invention, a crack determination is performed based on the first crack criteria, and when it is determined that no crack occurs, whether a total value of a plurality of the set push amounts reaches the maximum push amount. If it is determined that the total value of the pushing amount does not reach the maximum pushing amount, the next pushing amount is set, while the total value of the pushing amount reaches the maximum pushing amount. If it is determined that the plurality of pushing amounts and the number of pushing times set up to this point are determined as the optimum pressing conditions.

Therefore, when the total value of the plurality of pressing amounts reaches the maximum pressing amount, the plurality of pressing amounts and the number of times of pressing set up to this point are determined as the optimum pressing conditions, so that the optimum pressing conditions can be easily set. be able to.

In the optimization method of press molding of the present invention, a simulation of press working in consideration of springback using the analysis model is performed on the basis of set press conditions, and crack determination is performed by a preset second crack criteria. When it is determined that a crack has occurred, the material shape is changed to a non-cracking material shape and a simulation using the analysis model is performed.

Therefore, it is possible to set a highly accurate material shape by performing crack determination based on the result of a simulation of press working in consideration of springback.

In the press forming optimization method of the present invention, the accuracy of the material shape after the simulation is within a preset target value when a crack is determined by the second crack criteria and it is determined that no crack occurs. If it is determined that the accuracy of the material shape after the simulation is not within the preset target value, the analysis is performed by changing the material shape so that the accuracy of the material shape is within the target value. It is characterized by performing a simulation using a model.

Therefore, when the accuracy of the material shape after the simulation is not within the target value, it is possible to easily set the accuracy of the material shape within the target value by changing the material shape and performing the simulation again.

In the press molding optimization method of the present invention, when the accuracy of the material shape after the simulation is determined to be within the target value, the material shape after the simulation is determined as the optimum material shape. There is.

Therefore, by comparing the accuracy of the material shape after simulation with the target value to determine the optimum material shape, it is possible to improve the accuracy of the product manufactured by press working.

In the method for optimizing press molding of the present invention, a temporary mold shape setting step of setting a temporary mold shape, and a mold shape determining step of determining a mold shape in consideration of springback using the analysis model. The feature is that it is provided.

Therefore, the precision of the product manufactured by press working can be improved by determining the forming die shape in consideration of springback using the analysis model.

Further, the press molding optimization apparatus of the present invention uses an input unit for inputting an initial pushing amount and a temporary material shape, and an analysis model based on the initial pushing amount and the temporary material shape input from the input unit. The calculation unit that obtains the material shape in consideration of the press condition and the springback, which consists of the amount of pressing and the number of times of pressing by performing the simulation, and the material shape and the springback that were simulated by the press condition obtained by the calculation unit were considered. If it is determined that a crack has occurred in the material shape based on the cracking criteria, and if it is determined that a crack has occurred, the press conditions and the material shape are changed and the simulation is performed again. It is characterized by comprising a condition and a determination unit for determining the material shape.

Therefore, the press condition consisting of the pressing amount and the pressing frequency for the temporary material shape is determined using the analysis model, and the material shape considering the spring back is determined using the analysis model. The accuracy can be improved, and the analysis time for forming the optimum shape of the material can be shortened.

According to the method and apparatus for optimizing press forming of the present invention, the pressing condition including the pressing amount and the pressing frequency for the temporary material shape is determined using the analysis model, and the material shape considering the springback is used using the analysis model. Therefore, the accuracy of the product manufactured by the press working can be improved, and the analysis time in the optimum shape forming of the material can be shortened.

FIG. 1 is a block configuration diagram showing an optimizing device for press molding according to the first embodiment. FIG. 2-1 is a schematic diagram showing a press molding apparatus. FIG. 2-2 is a schematic view showing a molded product by the press molding device. FIG. 3 is a flowchart showing the method for optimizing the press molding of the first embodiment. FIG. 4 is a flowchart showing a method of determining press conditions. FIG. 5 is a flowchart showing a method for determining the material shape. FIG. 6 is a graph showing a deformation limit diagram. FIG. 7 is a flowchart showing a mold shape determination process in the press molding optimization method of the second embodiment.

Preferred embodiments of a press molding optimization method and apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and when there are a plurality of embodiments, the present invention also includes those configured by combining the embodiments.

[First Embodiment]
The press forming optimization method and apparatus of the first embodiment performs a simulation using a finite element method or the like in advance when a plate material is pressed to manufacture a product having a predetermined shape, and cracks or the like are generated during the press processing. This is to estimate the press conditions and the material shape where wrinkles do not occur.

FIG. 2-1 is a schematic diagram showing a press molding device, and FIG. 2-2 is a schematic diagram showing a molded product by the press molding device.

As shown in FIG. 2A, the press molding apparatus 20 includes a die 21 fixed at a predetermined position and a punch 22 arranged above the die 21 and capable of moving up and down. The die 21 is formed with a concave portion 21a, and the punch 22 is formed with a convex portion 22a facing the concave portion 21a. The material 31 has a hole 32 formed in the center thereof, and the hole 32 is smaller than the concave portion 21a and the convex portion 22a. The shapes of the concave portions 21a, the convex portions 22a, and the holes 32 may be circular, polygonal, or irregular. Further, the material 31 may not have the hole 32.

Then, the material 31 is placed on the die 21 and positioned so that the hole 32 is arranged on the recess 21a, and the punch 22 is lowered in this state. Then, the convex portion 22a of the punch 22 is fitted into the concave portion 21a of the die 21 via the material 31, so that the material 31 is bent around the hole 32 as shown in FIG. A molded product (product) 41 having 42 and holes 43 is manufactured.

In the first embodiment, when the material 31 having the holes 32 is pressed to manufacture the product 41, a simulation by analysis is performed in advance to determine the press conditions and material shape such that cracks or wrinkles do not occur during the press processing. presume.

FIG. 1 is a block diagram showing the optimizing device for press molding according to the first embodiment.

As shown in FIG. 1, the press molding optimizing device 10 of the first embodiment includes an analyzing device 11, and the analyzing device 11 includes an input unit 12, a display unit 13, and a storage unit 14. It is connected. Further, the analysis device 11 includes a calculation unit 15 and a determination unit 16, the calculation unit 15 includes a first calculation unit 15A and a second calculation unit 15B, and the determination unit 16 is a first determination unit. 16A and the 2nd determination part 16B are included.

The input unit 12 is for inputting an initial pressing amount (a fitting amount of the convex portion 22a of the punch 22 into the concave portion 21a of the die 21) and a temporary material shape of the material 31 having the holes 32 when performing the press working. ..

The analysis device 11 forms, for example, an analysis model for finite element method (FEM) analysis based on the input initial indentation amount and temporary material shape, and estimates optimal press conditions and material shape using this analysis model. To do. The display unit 13 displays the optimum press conditions and the material shape estimated by the analysis device 11, and the storage unit 14 stores various data obtained by the arithmetic operation of the analysis device 11 sequentially, cracking criteria described later, and the like.

The first calculation unit 15A performs a simulation using the analysis model with a predetermined first pushing amount smaller than the maximum pushing amount set based on the height of the flange portion 42 of the product 41. 16 A of 1st determination parts perform a crack determination by the crack criteria (1st crack criteria) preset with respect to the processed product (material shape) simulated using the analysis model by the 1st pushing amount. Here, when it is determined that the processed product is cracked, the first calculation unit 15A reduces the predetermined amount from the first pushing amount, resets the first pushing amount, and resets the first pushing amount as described above. 1 The simulation using the analysis model is performed again according to the pushing amount.

When the first determination unit 16A determines that the crack does not occur as a result of the crack determination based on the crack criteria, the first calculation unit 15A sets the second pushing amount obtained by subtracting the first pushing amount from the maximum pushing amount. , A simulation using an analysis model is performed according to the first pushing amount and the second pushing amount. 16 A of 1st determination parts perform a crack determination by the crack criteria with respect to the processed product simulated using the analysis model by the 1st pushing amount and the 2nd pushing amount.

The first determination unit 16A sets a pressing amount for a plurality of times by the crack determination based on the crack criteria, and determines whether the total value of the plurality of set pressing amounts has reached the maximum pressing amount. That is, in the first determination unit 16A, the first calculation unit 15A sets the pushing amount until the total value of the pushing amounts reaches the maximum pushing amount, and when the total value of the pushing amounts reaches the maximum pushing amount. , The plurality of pushing amounts and the number of pushings set up to this point are determined as the optimum pressing conditions.

On the other hand, the second calculation unit 15B performs a springback simulation on the material 31 having a temporary material shape using an analysis model based on the press condition determined by the first determination unit 16A. The second determination unit 16B cracks a workpiece having a temporary material shape by a preset cracking criteria (second cracking criteria) with respect to a workpiece in which springback is simulated using an analysis model based on the press condition. The decision is made. Here, when it is determined that the processed product is cracked, the second calculation unit 15B changes the material shape so that it does not crack, and similarly to the above, the analysis model based on the press condition is applied to the material of the changed material shape. The simulation of press working considering the springback using is performed again.

The second determination unit 16B determines whether or not the accuracy of the processed product in the material shape after simulation is within a preset target value. Here, if it is determined that the accuracy of the processed product in the material shape after simulation is not within the preset target value, the second calculation unit 15B determines that the accuracy of the processed product in the material shape after simulation is within the target value. Then, the simulation of press working considering the springback using the analysis model based on the press conditions is performed again on the material of the changed material shape as described above.

When the second determination unit 16B determines that the precision of the processed product in the material shape after simulation is within the target value, it determines the material shape at this time as the optimum material shape.

Here, a method of optimizing the press molding of the first embodiment by the above-described press molding optimizing apparatus 10 will be described. FIG. 3 is a flow chart showing an optimization method for press molding according to the first embodiment, FIG. 4 is a flow chart showing a method for determining a press condition, FIG. 5 is a flow chart showing a method for determining a material shape, and FIG. 6 is a modification. It is a graph showing a limit diagram.

As shown in FIG. 3, in step S11, the operator temporarily sets the material shape by inputting the temporary material shape of the material 31 having the hole 32 using the input unit 12. In step S12, the calculation unit 15 creates an analysis model for optimizing the press conditions and the material shape when the material 31 is press-molded. Then, in step S13, the first calculation unit 15A and the first determination unit 16A determine the pressing conditions including the pressing amount and the pressing frequency for the temporary material shape using the analysis model. Further, in step S14, the second calculation unit 15B and the second determination unit 16B determine the material shape in consideration of springback using the analysis model. Then, in step S15, the display unit 13 displays the determined press conditions and material shape.

In the pressing condition determination process, as shown in FIG. 4, it is assumed in step S21 that the maximum pushing amount L=Li. Here, i is the number of times of pressing (the number of times of pressing). In step S22, the first pushing amount (initial pushing amount) L ₁ is set, and the simulation using the analysis model is performed with the first pushing amount L ₁ . The first pushing amount L ₁ is larger than 0 and the maximum pushing amount L is smaller, and may be obtained by an empirical value, a preliminary simulation, an experiment, or the like.

In step S23, crack determination using the crack criteria is performed on the processed product simulated by using the analysis model with the first pushing amount L ₁ . This cracking criterion is implemented, for example, using a deformation limit diagram (FLD) as shown in FIG. With respect to the increase or decrease of the minimum principal strain, the tension-compression limit boundary where the maximum principal strain increases in the drawing area and the overhang area is set, and the forming limit (fracture limit) boundary is also set. An appropriate area A is set so that there is no crack between the boundary of forming limit. In step S23, it is determined whether or not the strain of the work piece simulated by using the analysis model is within the proper region A in the crack criteria based on the first pushing amount L ₁ . It should be noted that this cracking criterion may be set in plural instead of one, and may be changed for each processing for performing the cracking determination.

That is, in step S23, when it is determined that the strain of the processed product simulated using the analysis model with the first pushing amount L ₁ is not within the proper region A in the crack criteria and there is a crack (No), the process proceeds to step S24. Then, the first push amount L ₁ is reduced by a predetermined amount to reset the first push amount L ₁ . Then, in step S22, the simulation using the analysis model is performed again with the reset first pushing amount L ₁ . Then, in step S23, the crack determination is performed again on the basis of the crack criteria for the simulated workpiece using the analysis model with the reset first pushing amount L ₁ . Here, when it is determined again that the processed product has a crack (No), the process returns to step S24, the first pushing amount L ₁ is reset, and the same process as described above is performed.

If it is determined in step S23 that the strain of the processed product simulated using the analysis model with the first pushing amount L ₁ is within the proper region A in the crack criteria and there is no crack (Yes), in step S25. , It is determined whether or not the total value ΣLi of the maximum pushing amounts Li has reached the maximum pushing amount L. If it is determined that the total value ΣLi of the maximum pushing amounts Li has not reached the maximum pushing amount L (No), the first pushing amount Li ₊₁ is set to the total value ΣLi of the maximum pushing amounts Li in step S26. Then, the second pushing amount L ₂ is set by subtracting the first pushing amount L ₁ from the maximum pushing amount L.

In step S27, a simulation for removing the strain (compressive stress, tensile stress) in the processed product caused by the press working is carried out if necessary. In this case, for example, a simulation of heat treatment for stress relief is performed.

Then, the process returns to step S22, and the simulation using the analysis model is performed with the set second pressing amount L ₂ . Then, similarly to the above, the processes of steps S23, S24, S25, S26 and S27 are repeated.

When it is determined in step S25 that the total value of the plurality of set maximum pushing amounts Li has reached the maximum pushing amount L (Yes), the plurality of pushing amounts and the number of presses set so far are determined in step S28. Determine as the optimum press conditions.

On the other hand, in the material shape determination process, when the optimum press condition is determined in the press condition determination process, as shown in FIG. Then, the simulation of the press working considering the springback using the analytical model is performed. That is, when the material is pressed, springback occurs after the processing, and the processed product is deformed to return to the material shape. Here, a simulation is performed in consideration of the return amount due to this springback. In step S32, crack determination is performed based on the crack criteria with respect to the processed product in which the press working in consideration of the springback using the analysis model based on the press condition is simulated for the material of the temporary material shape. As the cracking criteria, the one shown in FIG. 6 used in the pressing condition determination process may be used.

That is, in step S32, the strain of the work piece simulated in the press work in consideration of the spring back using the analysis model based on the press condition for the material of the temporary material shape is not within the proper region A in the crack criteria, If it is determined that there is a crack (No), a material shape that does not crack is predicted in step S33, and the analysis model is corrected (mesh morphing, etc.) with the predicted material shape in step S34. Specifically, the shape and formation position of the hole 32 in the material 31 are corrected. Then, in step S31, the simulation of the press working considering the springback using the analysis model is performed again on the corrected material shape. Then, in step S32, crack determination is performed on the basis of the crack criteria for the processed product that simulates the press working considering the spring back using the analysis model based on the press condition for the material of the corrected material shape. .. Here, if it is determined again that the processed product has a crack (No), the process returns to step S33, the material shape that does not crack is re-estimated, and the same processing as described above is performed.

In step S32, if the strain of the processed product simulating springback is within the proper region A in the crack criteria and it is determined that there is no crack (Yes), the processed product in the material shape after simulation is determined in step S35. It is determined whether the accuracy of is within a preset target value. The target value may be the dimensional tolerance of the processed product that is the product 41, or may be a value that is stricter than the dimensional tolerance.

Here, if it is determined that the precision of the processed product in the material shape after the simulation is not within the target value (No), the material shape in which the precision of the processed product is within the target value is predicted in step S36, and the step In S34, the analysis model is corrected according to the predicted material shape. Then, in step S31, the simulation of the press working considering the springback using the analysis model is performed again on the corrected material shape. Then, in step S32, crack determination is performed on the basis of the crack criteria for the processed product that simulates the press working considering the spring back using the analysis model based on the press condition for the material of the corrected material shape. .. Here, if it is determined again that the processed product has a crack (No), the process returns to step S33, the material shape that does not crack is re-estimated, and the same processing as described above is performed.

If it is determined in step S35 that the precision of the processed product in the material shape after simulation is within the target value (Yes), the material shape set up to this point is determined as the optimum material shape in step S37. ..

As described above, in the press forming optimization method of the first embodiment, the temporary material shape setting step for setting the temporary material shape, the analysis model creating step for creating the analysis model of the press working, and the analysis model are used. A press condition determining step that determines the press condition consisting of the amount of pressing and the number of times the temporary material shape is pressed, and a material shape determining step that determines the material shape by press working analysis that considers springback using the analysis model and press conditions. have.

Therefore, by using the analysis model to determine the press conditions consisting of the indentation amount and the number of indentations with respect to the temporary material shape, and by using the analysis model to determine the material shape in consideration of springback, the product manufactured by press working The accuracy of can be improved, and the analysis time for forming the optimum shape of the material can be shortened.

In the press molding optimization method of the first embodiment, a simulation using an analysis model is performed with a predetermined first indentation amount smaller than the maximum indentation amount, and a crack determination is performed according to a preset first crack criteria, and a crack is detected. If it is determined that the cracking has occurred, the first pushing amount is reduced, the simulation using the analysis model is performed again, and the crack determination is performed based on the first crack criteria. Therefore, the amount of pushing once can be set to an appropriate amount.

In the method for optimizing press molding of the first embodiment, crack determination is performed based on the first crack criteria, and when it is determined that no crack occurs, analysis is performed using the second push amount obtained by subtracting the first push amount from the maximum push amount. A simulation using a model is performed, and a crack is judged according to the first crack criteria. Therefore, it is possible to set the pushing amount of plural times to an appropriate amount.

In the method for optimizing the press forming of the first embodiment, after setting the second indentation amount, a simulation for removing the residual strain of the material using the analysis model is performed. Therefore, highly accurate crack determination can be performed.

In the press molding optimization method of the first embodiment, the crack determination is performed based on the first crack criteria, and if it is determined that the crack does not occur, whether or not the total value of the plurality of set push amounts has reached the maximum push amount. If it is determined that the total value of the push-in amount has not reached the maximum push-in amount, the next push-in amount is set, while it is determined that the total value of the push-in amount has reached the maximum push-in amount. , The plurality of pushing amounts and the number of pushings set up to this point are determined as the optimum pressing conditions. Therefore, the optimum press conditions can be easily set.

In the press molding optimization method of the first embodiment, a press working simulation considering springback using an analytical model is performed based on the set press conditions, and a crack determination is performed based on a preset second crack criteria. When it is determined that a crack has occurred, the material shape is changed to a crack-free material shape and a simulation using the analysis model is performed. Therefore, a highly accurate material shape can be set.

In the press molding optimization method of the first embodiment, the crack determination is performed based on the second crack criteria, and if it is determined that no crack occurs, the accuracy of the material shape after simulation is within a preset target value. If it is judged that the accuracy of the material shape after simulation is not within the preset target value, the material shape accuracy is changed to within the target value and the analysis model is used. Perform a simulation. Therefore, the accuracy of the material shape can be easily set within the target value.

In the press molding optimization method of the first embodiment, when it is determined that the accuracy of the material shape after simulation is within the target value, the material shape after simulation is determined as the optimum material shape. Therefore, the precision of the product manufactured by the press working can be improved.

Further, in the press molding optimization apparatus of the first embodiment, based on the input unit 12 for inputting the initial pushing amount and the temporary material shape, and the initial pushing amount and the temporary material shape input from the input unit 12. A calculation unit 15 that obtains a material shape in consideration of a spring condition and a press condition including an amount of pressing and a number of times of pressing by performing a simulation using an analysis model, and a material shape and a spring that are simulated under the press condition obtained by the operation unit 15. A crack is judged based on the crack criteria for the material shape considering the back, and if it is judged that a crack has occurred, the press conditions and the material shape are changed and the simulation is performed again, while it is judged that no crack occurs. A determination unit 16 that determines the press conditions and the material shape is provided.

Therefore, the press condition consisting of the pressing amount and the pressing frequency for the temporary material shape is determined using the analysis model, and the material shape considering the spring back is determined using the analysis model. The accuracy can be improved, and the analysis time for forming the optimum shape of the material can be shortened.

[Second Embodiment]
FIG. 7 is a flowchart showing a mold shape determination process in the press molding optimization method of the second embodiment. The basic configuration of the present embodiment is almost the same as that of the above-described first embodiment, and will be described with reference to FIG. 1 and members having the same functions as those of the above-described first embodiment will be described. , The same reference numerals are given and detailed description is omitted.

In the second embodiment, after the press conditions and the material shape are determined by the press molding optimization method of the first embodiment, the die shape determination processing is performed.

That is, as shown in FIG. 7, in the mold shape determination process, in step S41, an analysis model is used for the temporary mold shape (die 21, punch 22) under predetermined press conditions and material shapes. We will perform a simulation of the press processing that takes into account the springback that was present. In step S42, crack determination is performed based on the crack criteria for the processed product that simulates the press working in consideration of the springback using the analysis model based on the press condition for the temporary die shape.

That is, in step S42, the strain of the work piece simulating the press working considering the spring back using the analysis model based on the press condition for the temporary die shape is not in the proper region A in the crack criteria, and the crack is generated. If it is determined (No), a mold shape that does not break is predicted in step S43, and the analysis model is modified (mesh morphing or the like) with the predicted mold shape in step S44. Then, in step S41, the simulation of the press working considering the springback using the analytical model is performed again on the corrected die shape. Then, in step S42, crack determination is performed by the crack criteria with respect to the processed product that simulates the press working considering the springback using the analysis model based on the press condition for the material of the corrected mold shape. To do. Here, if it is determined again that the processed product has a crack (No), the process returns to step S43 to re-estimate the mold shape without cracking, and the same processing as described above is performed.

If it is determined in step S42 that the distortion of the work piece simulating press working in consideration of springback is within the proper region A in the crack criteria and there is no crack (Yes), in step S45, the post-simulation It is determined whether or not the precision of the processed product in the material shape is within a preset target value.

If it is determined (No) that the accuracy of the processed product in the material shape after simulation is not within the target value (No), the mold shape in which the accuracy of the processed product is within the target value is predicted in step S46, In step S44, the analysis model is corrected based on the predicted die shape. Then, in step S41, the simulation of the press working considering the springback using the analytical model is performed again on the corrected die shape. Then, in step S42, crack determination is performed based on the crack criteria with respect to the processed product in which the pressed mold in which the spring back using the analysis model is taken into consideration is simulated for the corrected mold shape based on the pressing condition. Here, if it is determined again that the processed product has a crack (No), the process returns to step S43 to re-estimate the mold shape without cracking, and the same processing as described above is performed.

If it is determined in step S45 that the precision of the processed product in the die shape after simulation is within the target value (Yes), in step S47, the die shape set up to this point is set to the optimum die shape. To decide.

As described above, in the method for optimizing the press molding of the second embodiment, the temporary molding die shape setting step of setting the temporary molding die shape and the molding die shape in consideration of the springback are determined using the analysis model. And a molding die shape determining step.

Therefore, the precision of the product manufactured by press working can be improved by determining the forming die shape in consideration of springback using the analysis model.

In the above-described embodiment, the optimum press condition is determined and then the optimum material shape is determined. However, the optimum material shape is determined and then the optimum press condition is determined. May be. Further, after determining the optimum press condition and then determining the optimum material shape, the optimum press condition determination process and the optimum material shape determination process may be performed again.

Further, in the above-described embodiment, in step S23, it is determined that the strain of the processed product simulated with the first pushing amount L ₁ using the analysis model is within the proper region A in the crack criteria and there is no crack (Yes). ), the process proceeds to step S25. However, for example, a process of increasing the first pushing amount L ₁ may be performed.

Further, in the above-described embodiment, in the pressing condition determination process, the mold is not changed for each number of pressings, but the mold may be changed.

Further, in the above-described embodiment, the crack determination is performed by using the deformation limit diagram (FLD) as the crack criteria, but another crack criterion may be applied or a plurality of crack criteria may be used in combination. May be. Further, the pressing condition determining process and the material shape determining process may be applied as different crack criteria.

10 Optimizer for press molding 11 Analysis device 12 Input unit 13 Display unit 14 Storage unit 15 Calculation unit 15A First calculation unit 15B Second calculation unit 16 Judgment unit 16A First judgment unit 16B Second judgment unit

Claims (8)

In an optimization method of press molding in which a material having a hole is bent by pressing to form a flange portion having a hole,
A temporary material shape setting step for setting the temporary material shape,
An analysis model creation step for creating an analysis model for press working,
A press condition determining step of determining a press condition consisting of a pressing amount and a pressing frequency for the temporary material shape using the analysis model;
A material shape determining step of determining a material shape by press working analysis in consideration of springback using the analysis model and the press conditions,
Have a,
In the pressing condition determining step, a simulation using the analysis model is performed with a predetermined first pushing amount smaller than the maximum pushing amount set based on the height of the flange portion, and a first cracking criterion set in advance is used. When a crack is determined and it is determined that a crack has occurred, the first indentation amount is reduced and the simulation using the analysis model is performed again, and the crack is determined by the first crack criteria,
When it is determined by the crack determination of the first crack criteria that a crack does not occur, a simulation using the analysis model is performed with a second push amount obtained by subtracting the first push amount from the maximum push amount, and When it is determined that a crack has occurred by performing the crack determination based on the crack criteria, the second indentation amount is reduced and the simulation using the analysis model is performed again. By setting the push amount, the push amount and push count are determined once.
A method for optimizing press molding, which is characterized in that The method for optimizing press molding according to claim 1 , wherein after the second indentation amount is set, a simulation for removing the residual strain of the processed product caused by press working is carried out. When a crack is determined according to the first crack criteria and it is determined that no crack occurs, it is determined whether or not the total value of the plurality of set pushing amounts has reached the maximum pushing amount, and the total value of the pushing amount. When it is determined that has not reached the maximum push amount, while setting the next push amount, when it is determined that the total value of the push amount has reached the maximum push amount, set up to here The method for optimizing press molding according to claim 1 or 2 , wherein a plurality of pressing amounts and the number of times of pressing are determined as optimum pressing conditions. A simulation of press working in consideration of springback using the analysis model is performed based on the set press conditions, and a crack determination is performed according to a preset second crack criteria, and when it is determined that a crack has occurred, 4. The simulation using the analysis model is performed by predictively changing a material shape in which no crack occurs in the crack determination based on the second crack criteria, and the simulation is performed according to any one of claims 1 to 3 . Optimization method for press molding. When the crack determination is performed by the second crack criteria and it is determined that the crack does not occur, it is determined whether the accuracy of the material shape after simulation using the analysis model is within a preset target value, When it is determined that the accuracy of the material shape after the simulation is not within the preset target value, the simulation using the analysis model is performed by changing the material shape so that the accuracy of the material shape is within the target value. The method for optimizing press molding according to claim 4, which is performed. The optimum press molding according to claim 5 , wherein when the accuracy of the material shape after the simulation is determined to be within the target value, the material shape after the simulation is determined as an optimum material shape. Method. A preformed shape setting step of setting a preliminarily molded shape, according claim 1, characterized in that providing the mold shape determining step of determining a mold shape in consideration of springback using the analysis model Item 6. The method for optimizing press molding according to any one of items 5 . In a press molding optimizing device that bends a material having holes by press working to form a flange portion having holes,
An input unit for inputting the initial pushing amount and temporary material shape,
An arithmetic unit that obtains a material shape in consideration of a press condition including a pressing amount and the number of pressings and a springback by performing a simulation using an analysis model based on the initial pressing amount and the temporary material shape input from the input unit. When,
Cracking is performed on the material shape simulated by the computing unit under the pressing conditions by the first cracking criterion, and the material shape in consideration of the springback determined by the computing unit is cracked by the second cracking criterion. If it is determined that a crack has occurred according to the first crack criteria, the press conditions are changed and a simulation is performed again, and if it is determined that a crack has occurred due to the second crack criteria, the material shape On the other hand, while performing the simulation again, a determination unit that determines the press condition and the material shape when it is determined that no crack occurs due to the first crack criteria and the second crack criteria .
Bei to give a,
The calculation unit performs a simulation using the analysis model with a predetermined first pushing amount smaller than the maximum pushing amount set based on the height of the flange portion, and the determining unit sets the first preset amount. A crack is determined by the crack criteria, and when it is determined that a crack has occurred, the first indentation amount is reduced and the simulation using the analysis model is performed again, and the crack is determined by the first crack criteria.
If it is determined by the crack determination of the first crack criteria that a crack does not occur, a simulation using the analysis model is performed with a second push amount obtained by subtracting the first push amount from the maximum push amount, and When it is determined that a crack has occurred by performing the crack determination based on the crack criteria, the second indentation amount is reduced and the simulation using the analysis model is performed again. By setting the push amount, the push amount and push count are determined once.
An apparatus for optimizing press molding, which is characterized in that

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