阅读说明：本技术 模压成型方法、刚性提高位置确定方法、模压成型系统及模压成型品 (Compression molding method, rigidity-improving position determining method, compression molding system, and compression molded article ) 是由 仮屋崎祐太 藤井祐辅 山崎雄司 于 2019-01-15 设计创作，主要内容包括：本发明目的在于,提供能够高效地抑制回弹且能够简便地确定由刚性提高带来的回弹减小效果大的位置的模压成型方法,由板状材料模压成型出规定形状的成型品时使用的模压成型方法包括下述工序：改变进行约束的位置而反复进行使用实施了下述处理的解析模型进行的回弹解析,确定由刚性提高带来的回弹减小效果大的位置的第1工序,该处理中,在对具有上述规定形状的成型品模型的特定位置的伸缩变形进行约束的同时允许旋转,由此假想地使刚性提高；对上述板状材料的与上述成型品模型的在上述第1工序中确定的位置对应的位置实施刚性提高措施的第2工序；由实施了上述刚性提高措施的上述板状材料模压成型出所述模压成型品的第3工序。(The present invention aims to provide a press molding method capable of efficiently suppressing springback and easily determining a position where a spring-back reducing effect due to an improvement in rigidity is large, the press molding method used when a molded article having a predetermined shape is press-molded from a plate-like material, the press molding method including the steps of: a 1 st step of repeating springback analysis using an analysis model subjected to a process of restricting the position of restriction while allowing rotation while restricting the expansion and contraction deformation of a specific position of the molded product model having the predetermined shape, thereby virtually increasing the rigidity, and determining a position where the springback reduction effect by the improvement of the rigidity is large; a 2 nd step of applying rigidity improvement means to a position of the plate-like material corresponding to the position of the molded product model specified in the 1 st step; and a 3 rd step of press-molding the press-molded article from the plate-like material subjected to the rigidity improving measure.)

1. A press molding method for press molding a press molded article having a predetermined shape from a plate-like material, comprising:

a step 1 of changing a position to be restrained and repeating a springback analysis using an analysis model subjected to a process of restraining an expansion and contraction deformation of a specific position of a molded product model having the predetermined shape while allowing rotation to thereby improve the rigidity in an imaginary manner, and determining a position where a springback reduction effect by the improvement of the rigidity is large;

a 2 nd step of applying rigidity improvement means to a position of the plate-like material corresponding to the position of the molded product model specified in the 1 st step; and

and a 3 rd step of press-molding the press-molded article from the plate-like material subjected to the rigidity improving measure.

2. A molding press molding method according to claim 1,

in the step 1, when the springback analysis is repeated while changing the position where the restraint is performed,

the following treatments were first performed: dividing the entire molded product model to set a plurality of first divided positions, performing the springback analysis using the first divided positions in order as the constraining positions, and specifying a position having a large springback reduction effect due to an improvement in rigidity among the first divided positions,

then, the following processes are performed once or repeatedly: the position of the large spring-back reduction effect due to the rigidity improvement determined in the previous time is divided to set a plurality of subdivided positions, the subdivided positions are sequentially used as the positions for restraining to perform the spring-back analysis, and the position of the large spring-back reduction effect due to the rigidity improvement is further narrowed and determined in the subdivided positions.

3. A rigidity-improvement position specifying method for specifying a position at which a spring back reducing effect by rigidity improvement is large in a plate-like material used when a press molding product having a predetermined shape is press-molded,

repeating springback analysis by changing the position of constraint using an analysis model subjected to a process for virtually improving the rigidity by allowing rotation while constraining the expansion and contraction deformation of a specific position of the molded product model having the predetermined shape and repeating springback analysis to obtain a position of the molded product model where the springback reduction effect by the improvement of the rigidity is large,

the position of the plate-like material where the effect of reducing springback by increasing rigidity is large is determined by using correspondence with the position of the molded product model where the effect of reducing springback by increasing rigidity is large.

4. A press molding system used when a press molded article having a predetermined shape is press molded from a plate-like material, comprising:

a rigidity-improvement position specifying device that changes a position where the restraint is performed and repeats springback analysis using an analysis model to which processing is performed to obtain a position where a springback reduction effect by the improvement of rigidity of the molded product model is large, and specifies a position where a springback reduction effect by the improvement of rigidity of the plate-like material is large by using a correspondence relationship with a position where a springback reduction effect by the improvement of rigidity of the molded product model is large, the processing being performed to allow rotation while restraining expansion and contraction deformation of a specific position of the molded product model having the predetermined shape, thereby improving the rigidity in an imaginary manner; and

and a press molding device that press-molds the press molded product from the plate-shaped material at a position where the effect of reducing springback due to the increase in rigidity determined by the rigidity-increase-position determining device is large.

5. A molded article obtained by molding by the molding method according to claim 1 or 2.

Technical Field

The present invention relates to a press molding method for reducing spring back occurring in press molding of a plate-shaped material including a plurality of press molding steps and improving dimensional accuracy of a press molded article, a method for determining a position for improving rigidity of a plate-shaped material, a press molding system, and a press molded article molded by using the press molding method.

Background

In recent years, the use of high-strength steel sheets has been expanding in order to reduce the weight of automobile bodies for the purpose of improving fuel efficiency. By using the high-strength steel sheet, the strength and rigidity of the automobile body and the absorption energy at the time of collision can be improved without increasing the sheet thickness.

However, in the press molding which is frequently used in general in the processing of vehicle body parts, a shape freezing failure called springback (spring back) becomes a problem. Springback occurs when a press-molded article press-molded from a steel plate as a plate-shaped material is released from a mold, and increases as the material strength of the steel plate increases. Since springback not only deteriorates the appearance quality but also causes poor welding during assembly, springback measures are essential for the expansion of the application of high-strength steel sheets.

The cause of the springback is that a bending moment generated by the unevenness of the residual stress is released at the time of releasing the molded product to cause elastic recovery. Therefore, conventionally, as a measure against springback, a method of alleviating unevenness of residual stress has been proposed.

Patent document 1 proposes the following technique: an intermediate product having embossed portions disposed on the stretched flange portions and extra beads disposed on the shrunk flange portions is molded, and in molding of a final molded product, the embossed portions are crushed to apply compressive stress to the stretched flange portions and the extra beads apply tensile stress to the shrunk flange portions, whereby the residual stress distribution of the molded product is made uniform.

Patent document 2 proposes the following technique: a press molding analysis by a finite element method is performed to obtain residual stress before mold release in each region obtained by dividing the shape of a press molded product into a plurality of regions, springback analysis based on data after the residual stress is eliminated and results of the springback analysis based on data before the residual stress is eliminated are compared, the contribution degree of the residual stress to springback in each region is calculated, an uneven portion is provided in a portion corresponding to a punch bottom portion of a molding die with respect to a region with a high contribution degree, a material of a flange portion is made to flow into the punch side in the vicinity of a bottom dead center in the middle of press molding, and a compressive stress opposing a tensile stress toward the outside in the longitudinal direction of the flange portion is generated by movement of the material to the uneven portion, thereby relaxing the tensile stress of the flange portion.

Patent document 3 proposes the following technique: the shape of the molded product is divided into a plurality of regions, an arbitrary region is selected from the plurality of regions, the Young's modulus in an arbitrary direction in the X, Y, Z direction of the selected region is changed, the rebound analysis of the molded product after the Young's modulus change is performed, the difference between the rebound amount of the molded product before the Young's modulus change and the rebound amount of the molded product after the Young's modulus change is obtained, and the stress region and the stress direction effective for the measure against the rebound are determined by performing the above-described processing for each of the selected regions and for each of the specified directions.

Patent document 4 proposes the following technique: a shape optimization analysis such as a topology optimization analysis is performed on an analysis model of a molded product, a position having a high contribution to rigidity is detected, and a rigidity improvement measure such as fitting or overlapping a material having a large plate thickness, a material having a high rigidity, or overlapping the same material is performed at a corresponding position of a blank, thereby effectively suppressing springback.

Disclosure of Invention

Problems to be solved by the invention

As a method for making the residual stress uniform, patent document 1 proposes a method of forming an embossed portion in a stretched flange portion and forming an extra bead in a shrunk flange portion, but in a molded article having a complicated shape, it is not easy to determine a position to which a countermeasure shape is to be applied.

As a method for relieving residual stress, patent document 2 proposes a method for providing a concave-convex shape, and patent document 3 proposes a method for determining a stress region and a direction effective for springback by changing the young's modulus in a specific direction, but in a low-rigidity member, springback occurs even in the case of low residual stress, and therefore, even if the residual stress at a specific position is reduced, there are cases where springback remains due to residual stress at other positions, and further, there are cases where springback occurs due to new stress generated by providing a shape to the specific position, and therefore the above-mentioned methods are not sufficient as measures for springback.

The method of detecting the position of the rigidity contribution of patent document 4 can realize a design with a high degree of freedom by introducing a shape optimization analysis such as a topology analysis in the initial stage of the design, but the shape optimization analysis requires not only a high level of knowledge but also a shape that is not practically feasible and a very complicated shape, and has a drawback that an optimal shape of a molded product cannot be easily obtained.

That is, the problems to be solved by the prior art are listed as follows.

(1) A spring back countermeasure effective for a member having a low rigidity.

(2) Regardless of the shape of the member, a position where the spring-back reduction effect due to the increase in rigidity is large can be determined.

(3) The position at which the rigidity improvement measure shown in (2) above is taken can be easily determined.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a press-molded product having a small amount of springback after press molding and excellent shape fixability, by specifying a position effective for suppressing springback due to an increase in rigidity.

Means for solving the problems

A press molding method according to the present invention for advantageously solving the above-described problems is a press molding method used when a press molded article having a predetermined shape is press-molded from a plate-like material, the press molding method including the steps of:

a step 1 of changing a position to be restrained and repeating a springback analysis using an analysis model subjected to a process of restraining an expansion and contraction deformation of a specific position of a molded product model having the predetermined shape while allowing rotation to thereby improve the rigidity in an imaginary manner, and determining a position where a springback reduction effect by the improvement of the rigidity is large;

a 2 nd step of applying rigidity improvement means to a position of the plate-like material corresponding to the position of the molded product model specified in the 1 st step; and

and a 3 rd step of press-molding the press-molded article from the plate-like material subjected to the rigidity improving measure.

In addition, a rigidity improvement position specifying method according to the present invention for advantageously solving the above-described problems is a method for specifying a position at which a spring back reduction effect by rigidity improvement of a plate-like material used in press molding of a press molded article having a predetermined shape is large,

repeating springback analysis by changing the position of constraint using an analysis model subjected to a process for virtually improving the rigidity by allowing rotation while constraining the expansion and contraction deformation of a specific position of the molded product model having the predetermined shape and allowing rotation, and determining a position of the molded product model where the springback reduction effect by the improvement of the rigidity is large,

the position of the plate-like member where the effect of reducing springback by increasing rigidity is large is determined by the correspondence with the position of the molded product model where the effect of reducing springback by increasing rigidity is large.

Further, a press molding system of the present invention for advantageously solving the above-described problems is a press molding system used when a press molded article having a predetermined shape is press-molded from a plate-like material, the press molding system including:

a rigidity-improvement position specifying device that changes a position where the restraint is performed and repeats a springback analysis using an analysis model to which a process is performed, determines a position of the molded product model where a springback reduction effect by the improvement of rigidity is large, and specifies a position of the plate-shaped material where the springback reduction effect by the improvement of rigidity is large by using a correspondence relationship with the position of the molded product model where the springback reduction effect by the improvement of rigidity is large, the process being performed to allow rotation while restraining a stretching deformation of a specific position of the molded product model having the predetermined shape, thereby improving the rigidity in an imaginary manner; and

and a press molding device that press-molds the press molded product from the plate-shaped material at a position determined by the rigidity-improvement position determination device and at which the effect of reducing the spring-back due to the improvement in rigidity is large.

Further, a press-molded article of the present invention, which advantageously solves the above-mentioned problems, is characterized in that it is press-molded by the press-molding method of the present invention.

Effects of the invention

In the press molding method of the present invention, in order to evaluate the effect of reducing springback in the case of improving the rigidity of a press molded article, a mold of the molded article having the shape of the press molded article was partially subjected to a rigidifying treatment and springback analysis was performed. The rigidifying treatment in the present invention means the following method: the rigidity is improved in a virtual manner by giving a deformation condition for restricting the expansion and contraction deformation and allowing the rotation to the molded product at the bottom dead center.

According to the press molding method of the present invention, the position at which the rigidization treatment is performed is variously changed and the springback is analyzed to determine a position in the molded product mold where the springback suppression effect due to the improvement of rigidity is high, and the rigidity improvement measure is performed on the plate-like material at a position corresponding to the position of the molded product mold where the rigidity is improved, so that the springback of the plate-like material can be efficiently suppressed.

Further, according to the press molding method of the present invention, in order to specify the optimum rigidity improvement position, it is only necessary to repeat the springback analysis while changing the position to be subjected to the rigidization processing, without performing the optimization analysis requiring advanced knowledge and skill such as topology analysis, and therefore, it is possible to easily specify the position where the springback reduction effect by the rigidity improvement is large.

In the press molding method of the present invention, when the position where the restraint is performed is changed and the springback analysis is repeated in the step 1,

the following treatments were first performed: dividing the entire molded product model to set a plurality of first divided positions, performing the springback analysis using the first divided positions in order as the positions to be restrained, and specifying a position having a large springback reduction effect due to an improvement in rigidity among the first divided positions,

then, the following processes are performed once or repeatedly: the position where the springback reduction effect by the rigidity improvement is large is divided to set a plurality of divided positions, and the springback analysis is performed using the divided positions in order as the position to be restrained, and the position where the springback reduction effect by the rigidity improvement is large is further narrowed and specified in the divided positions.

This makes it possible to efficiently and accurately specify a position where the spring back reduction effect due to the improvement in rigidity is large.

Further, according to the rigidity improvement position specifying method of the present invention, when specifying the position where the spring back reducing effect by rigidity improvement is large in the plate-like material used in press molding of the press molded product having the predetermined shape, the method includes the steps of repeating springback analysis by changing a position where constraint is performed using an analysis model to which processing (processing for virtually improving rigidity by allowing rotation while constraining expansion and contraction deformation of a specific position of a molded product model having the predetermined shape) is performed, to obtain a position where a springback reduction effect by improvement of rigidity of the molded product model is large, and determining a position where a springback reduction effect by improvement of rigidity of the plate-like material is large by using a correspondence relationship with a position where a springback reduction effect by improvement of rigidity of the molded product model is large.

On the other hand, in the press molding system of the present invention, the rigidity-improvement position specifying means repeatedly performs springback analysis using an analysis model on which processing (processing for virtually improving rigidity by restricting only expansion and contraction deformation at a specific position of the molded product model having the predetermined shape) is performed by changing a position where the restriction is performed, obtains a position where a springback reduction effect by improvement of rigidity of the molded product model is large, specifies a position where a springback reduction effect by improvement of rigidity of the plate-like material is large by using a correspondence relationship with a position where a springback reduction effect by improvement of rigidity of the molded product model is large,

the plate-shaped material is molded into the molded article by the molding die, which is the molding apparatus, at a position where the effect of reducing the spring back due to the increase in rigidity determined by the rigidity-increase-position determining means is large.

Therefore, according to the press molding system of the present invention, springback of the press molded product can be suppressed efficiently.

Further, according to the press-molded article of the present invention, since it is press-molded by the press-molding method of the present invention, springback can be suppressed efficiently.

Drawings

Fig. 1 is a process flow chart showing steps of a press molding method according to an embodiment of the present invention and a rigidity improvement position determination method according to an embodiment of the present invention, which are performed by a press molding system according to an embodiment of the present invention.

FIG. 2 is a perspective view schematically showing an example of a molded article and a molded article mold having the shape of the molded article in the molding method of the above embodiment which is performed by the molding system of the above embodiment.

Fig. 3 is an explanatory diagram showing an example of division of the molded product model of the above example into three regions.

Fig. 4 is an explanatory diagram showing an example of division in which the central region determined to have a large effect of reducing springback due to an increase in rigidity among the three regions of the molded product model of the above example is further divided into 9 pieces.

Detailed Description

As a press molding method according to an embodiment of the present invention, first, it is determined based on information on the material, shape, and the like of a press molded article whether or not the press molding method according to the embodiment can be applied when a blank formed of a plate-like material is press molded into a press molded article of a predetermined shape. When it is determined that the press molding method of the present embodiment can be applied, a position of the molded product mold where the effect of reducing springback due to the improvement of rigidity is large is determined (step 1), a measure for improving rigidity is performed on a position of the blank corresponding to the position of the molded product mold determined in step 1 (step 2), and press molding is performed on the blank.

The plate-like material of the press molded article to which the press molding method of the present embodiment can be applied is preferably a steel plate having a tensile strength of 440MPa or more, more preferably 780MPa or more. This is because it is difficult to perform press molding using other press molding methods. In addition, the shape of the press-molded article to which the press-molding method of the present embodiment can be applied is such that the length in the short dimension direction (X-axis direction in fig. 4) after press-molding is 300 times or more the plate thickness and 10 times or more the height of the press-molded article, and for example, automobile body parts made of steel plate often have the shape of the press-molded article. In the determination as to whether or not the press molding method of the present embodiment relating to the shape of the press molded product can be applied, the second moment of cross section may be calculated from the cross sectional shape of the press molded product and used as the threshold value.

The following describes a press molding system and a press molding method according to the present embodiment, and a rigidity improvement position determination method according to the present embodiment, with reference to the flowchart shown in fig. 1 and the example of a press molded product shown in fig. 2. Fig. 1 is a flowchart showing steps of a press molding method according to an embodiment of the present invention performed by a press molding system according to an embodiment of the present invention and a method for determining a position for improving rigidity according to an embodiment of the present invention, and fig. 2 is a perspective view schematically showing an example of a press molded product and a mold of a molded product having a shape of the press molded product in the press molding method according to the embodiment performed by the press molding system according to the embodiment, as viewed obliquely from above.

As shown in the flowchart of fig. 1, the press molding method of the present embodiment includes all 4 steps from the press molding analysis step S1 to the press molding step S4, and in the first press molding analysis step S1, for example, a molded product model of the press molding M shown in fig. 2 is first created based on the shape of the press mold, the shape of the blank, the material of the blank, and the like (for convenience, the same reference numeral M as that of the press molding is used), and the press molding is simulated (simulated) by numerical calculation using a finite element method by a normal computer using this molded product model M, so as to obtain the molded shape of the press molding M at the molding bottom dead center of the press mold and the residual stress of each part of the molded shape.

The next rigidity improvement position determination step S2 includes a rigidization processing step S2-1 and a springback analysis step S2-2 executed by the above-mentioned normal computer, and in the rigidization processing step S2-1, the press-molded product M at the molding bottom dead center is divided into a plurality of regions, and a rigidization process for restraining the expansion and contraction deformation and allowing the rotation is performed for each region to create an analysis model. Then, in the springback analysis step S2-2, the final shape of the analysis model after the residual stress of each part of the analysis model at the molding bottom dead center of the press mold is released is analyzed.

That is, in the rigidity improvement position determination step S2, the rigidity improvement position determination method of the above embodiment is performed in the rigidization processing step S2-1 and the springback analysis step S2-2, and the springback reduction effect due to the improvement in rigidity is evaluated by comparing the springback amount in the case where the rigidization processing is not performed with the springback amount in the case where the rigidization processing is performed in each region. In this evaluation, as the springback amount, the "sag" or "rise" and the "twist" of the end portion of the analysis model were compared, as described later. At this time, by repeating the springback analysis while gradually narrowing the divided region of the press molded article M, it is possible to specify a position where the effect of improving the rigidity is large.

For example, fig. 3 is an explanatory view showing an example of primary division in which the molded article model M of the above example is viewed from obliquely above and the entire molded article model M is roughly divided into three regions, and as shown in fig. 3, the entire molded article model M at the molding bottom dead center of the press mold is divided into three parts in the longitudinal direction thereof, and three primary division regions (primary division positions) R11, R12, and R13 are set. Then, the respective primary divided regions of R11 to R13 of the molded product model M are subjected to a rigidization process in which the expansion and contraction deformation is restrained without restraining the rotation, and analysis models are created and the springback analysis is performed.

Fig. 4 is an explanatory view of the molded article model M as viewed from obliquely above and showing a finely divided example in which the center primary divided region R12, which is determined to have a large springback reduction effect due to the improvement in rigidity, of the three primary divided regions R11, R12, and R13 of the molded article model M of the above example is further finely divided into 9, and as shown in the coordinate system of fig. 4, the short dimension direction of the molded article model M is set to the X direction, the long dimension direction is set to the Y direction, and the height direction is set to the Z direction, and the Y direction positive side is set to the right direction of the paper surface, the negative side is set to the left direction of the paper surface, the Z direction positive side is set to the near-front direction of the paper surface, and the negative side is set to the deep-back direction. The "sag" is a phenomenon of displacement to the negative side in the Z direction due to springback, "float" is a phenomenon of displacement to the positive side in the Z direction due to springback, and "twist" is a phenomenon of twisting of the molded product model M due to the difference in the Z-direction displacement amount depending on the location.

In the rigidity improvement position determination step S2, the springback amount of the molded product model M in the case where no rigidization process is performed in any of the primary divided regions is compared with the springback amount of the molded product model M in the case where the rigidization process is performed on each of the primary divided regions R11 to R13 with respect to the sag amount, the floating amount, and the torsion angle, respectively, and when the springback reduction effect of the primary divided region R12 is maximized, for example, the primary divided region R12 is further divided into 9 sub-divided regions (sub-divided positions) R21 to R29 in a fine manner as shown in fig. 4, the rigidization process is performed on each sub-divided region in the same manner as the primary divided region, analysis models are created and the springback analysis is performed, and the sag amount, the floating amount, and the torsion angle, which are the springback amounts, are compared, respectively. The process of performing the fine division and the springback analysis once or twice or more after the initial division and the springback analysis further narrows down the region (position) where the springback reduction effect by the rigidity improvement is large, and the position where the springback reduction effect by the rigidity improvement is the maximum can be determined efficiently and with high accuracy.

In the rigidity improvement measure step S3, the rigidity improvement measure is locally applied to a position of the actual blank corresponding to the position of the molded article model M determined in the rigidity improvement position determination step S2 where the effect of reducing the springback due to the improvement in rigidity is large. As a measure for locally improving the rigidity of the blank member, it is possible to appropriately select and apply a method of increasing the plate thickness at a corresponding position of the blank member, a method of attaching a material identical to or having higher rigidity to the corresponding position of the blank member, a method of replacing the material at the corresponding position of the blank member with another material having high rigidity, a method of providing a concave-convex shape to the corresponding position, and the like, depending on the shape of the molded product, the mold structure, and the like.

Then, in the press molding step S4, press molding of the press molded article M is performed using the press mold determined up to the previous step and the blank subjected to the rigidity improvement measure.

Therefore, the press molding analysis step S1 and the rigidity improvement position determination step S2 correspond to the 1 st step in the press molding method of the present invention, and the rigidity improvement measure step S3 and the press molding step S4 correspond to the 2 nd step and the 3 rd step in the press molding method of the present invention, respectively. The computer that executes the press molding analysis step S1 and the rigidity-improvement-position determination step S2 based on a program provided in advance corresponds to the rigidity-improvement-position determination device in the press molding system of the present invention, and the press mold that performs press molding of the press molded product M in the press molding step S4 corresponds to the press molding device in the press molding system of the present invention. The rigidity improvement position determination step S2 implements the rigidity improvement position determination method according to the above embodiment.

(examples)

Examples of the present embodiment are explained below. As a countermeasure against the spring back of the vehicle body component having low rigidity, the press molding method of this embodiment is applied to press molding of a front pillar lower interior member material as the vehicle body component. The application details and the mechanical property values are as follows.

Application details: 980MPa high-tension steel plate/plate thickness 0.9 mm/front column lower part inner member

Mechanical property values: YP: 620MPa, TS: 1030MPa, El: 15 percent of

The shape of the above-mentioned application-specific molded article M is shown in FIG. 2. As described in the above embodiment, first, a press molding analysis is performed to obtain the part shape and the stress state of the vehicle body part at the bottom dead center of the press mold. Then, as shown in fig. 3, in order to specify the effective rigidity position, which is the position where the effect of reducing the springback due to the improvement in rigidity is large, the shape of the press molding product M is divided into three parts, and springback analysis is performed on each of the three analysis models in which the rigidization treatment is performed on the different primary divided regions.

As a result of the above-described springback analysis, since the effect of the first divided region (position) R12 in the central portion of the component is maximized, in this embodiment, as shown in fig. 4, the first divided region (position) R12 is further subdivided into 9 pieces, and springback analysis is performed on each of the 9 analysis models in which the rigidization is performed on the mutually different subdivided regions, and as a result, the effect of the subdivided region (position) R23 is maximized, and therefore, the subdivided region (position) R23 in which the first divided region (position) R12 previously determined as the rigid effective position is further narrowed down is determined (updated) as the rigid effective position.

In the above embodiment, sagging and twisting occur as springback. Table 1 below shows the results of analysis of the rigidization position and the spring back amount (sag amount, torsion angle) in the above example. Table 1 shows a case where the rigidizing position R0 is not subjected to the rigidizing treatment. In addition, bold characters show regions (positions) where the effect of the rigidization processing is the greatest in each of the analysis model in fig. 3 and the subdivided analysis model in fig. 4.

[ Table 1]

By subjecting the blank identified in this example to the rigidifying treatment at the position R23 and then actually press-molding the above-described finely molded product M using the blank, a molded product having a small spring back after press-molding and excellent shape fixability can be press-molded.

The above description has been made based on the illustrated examples, but the press molding method, the rigidity improvement position determination method, the press molding system, and the press molded article of the present invention are not limited to the above examples, and can be appropriately modified within the scope of the claims, and for example, the shape of the press molded article may be a shape other than the shape shown in fig. 2, and the division form of the mold of the molded article may be a form other than the forms shown in fig. 3 and 4.

Industrial applicability

As described above, according to the press molding method, press molding system, and press molded article of the present invention, it is possible to efficiently suppress springback and to easily specify a position where the effect of reducing springback due to the improvement in rigidity is large.

In addition, according to the rigidity improvement position specifying method of the present invention, it is possible to easily specify a position where the spring back reduction effect by the improvement of rigidity is large.

Description of the reference numerals

M compression molding product (molded product model)

Primary R11-R13 division regions

R21-29 subdivision area

S1 compression Molding analysis Process

S2 rigidity-improved position specifying step

S2-1 rigidifying treatment Process

S2-2 springback analysis step

S3 Process for rigidity improvement

S4 compression Molding Process