Drawing flanging die and method for controlling flanging springback of sheet metal part

Abstract

The invention relates to a drawing and flanging die and a method for controlling flanging springback of a sheet metal part, the drawing and flanging die comprises a drawing male die and a drawing female die, a blanking gap is arranged between the drawing male die and the drawing female die, and the blanking gap comprises a plane gap section, a flanging fillet gap section and a flanging section gap section which are communicated in sequence; the flanging section gap section comprises a flanging springback value small linear gap section, one end of the flanging springback value small linear gap section is communicated with the flanging rounded corner gap section, and the flanging springback value small linear gap section obliquely extends in the direction close to the drawing male die from the connecting position of the flanging springback value small linear gap section and the flanging rounded corner gap section. And the flanging springback value small linear gap section is used for pre-shaping the flanging section section C part of the sheet metal part to form a pre-shaped flanging springback value small linear section D1. And the straight line section D1 with the small pre-shaping flanging springback amount has the smaller springback tendency, so that the sheet metal part can keep the shape and the size meeting the design requirement after being unloaded.

Description

Technical Field

[0001] The present application relates to the field of automobile cover mold tooling, and in particular to a drawing and flanging mold and a method for controlling the flanging springback of a sheet metal part. Background Art

[0002] In the stamping process, flanging is a common processing method. The ideal flanging state is as follows Figure 1 As shown, the cross-sectional shape of the sheet metal part 1 includes a sheet metal part plane section A, a flanged corner section B and a flanged cross-sectional section C. The corresponding drawing die is as follows Figure 2 As shown in the figure, due to the plastic deformation of the material and the influence of internal stress during the flanging process, springback often occurs, resulting in the size and shape of the stamping parts not meeting the requirements.

[0003] Flanging springback refers to the phenomenon that when the external load is removed during the stamping process, the material in the plastic deformation zone deforms the sheet metal due to residual stress. This phenomenon is caused by the elastic recovery of the elastic deformation zone of the sheet metal and the elastic recovery of the elastic deformation part of the material in the plastic deformation zone, causing the shape and size of the sheet metal to change in the opposite direction of the deformation during loading.

[0004] This flanging springback problem is a difficult point in the sheet metal stamping process. Figure 3 As shown, the ideal state C of the flange cross-section shape becomes a straight line segment C1 with a small flange springback, a straight line segment C3 with a large flange springback, and a transition straight line segment C2 between segments C1 and C3.

[0005] In the related art, the traditional solution is to add a mold for the side shaping process to reduce the springback of the flanging through side shaping. Since the mold for the side shaping process of the sheet metal part needs to be added with an additional set of molds, the mold structure becomes complicated and the cost increases. Summary of the invention

[0006] The present application provides a drawing flanging die and a method for controlling the flanging springback of a sheet metal part, which can avoid the traditional method of adding a side shaping process die and reduce the flanging springback through side shaping. Since the sheet metal part needs to add a set of die for the side shaping process, the die structure becomes complicated and the cost increases.

[0007] In a first aspect, an embodiment of the present application provides a drawing and flanging die, comprising:

[0008] A drawing punch and a drawing die, wherein a blanking gap is provided between the drawing punch and the drawing die, and the blanking gap comprises a plane gap section, a flanged corner gap section and a flanged section gap section which are connected in sequence;

[0009] The flanging cross-section gap section includes a straight line gap section with small flanging springback, one end of which is connected to the flanging rounded corner gap section, and the straight line gap section with small flanging springback extends obliquely from the connection with the flanging rounded corner gap section toward the direction close to the drawing punch, and the straight line gap section with small flanging springback is used to pre-shape the flanging cross-section section C of the sheet metal part to form a pre-shaped straight line section D1 with small flanging springback.

[0010] In combination with the first aspect, in one embodiment, a portion where one end of the straight line gap section with a small amount of flanging rebound is connected to one end of the flanging rounded corner gap section is chamfered.

[0011] In combination with the first aspect, in one embodiment, the flange cross-section gap segment includes a linear gap segment with a large flange rebound amount, and one end of the linear gap segment with a large flange rebound amount is connected to one end of the linear gap segment with a small flange rebound amount;

[0012] The straight line gap section with large flanging springback extends obliquely from the connection with the straight line gap section with small flanging springback toward the direction close to the drawing punch, and the straight line gap section with large flanging springback is used to pre-shape another part of the flanging section section C of the sheet metal part to form a pre-shaped straight line section D3 with large flanging springback.

[0013] In combination with the first aspect, in one implementation, the inclination angle of the straight line gap section with a small flanging rebound amount is smaller than the inclination angle of the straight line gap section with a large flanging rebound amount.

[0014] In combination with the first aspect, in one embodiment, the flange section gap segment also includes a transition straight line gap segment, which is connected between the straight line gap segment with small flange springback and the straight line gap segment with large flange springback, and the transition straight line gap segment is parallel to the plane gap segment. The transition straight line gap segment is used to pre-shape the remaining part of the flange section segment C of the sheet metal part into a pre-shaped transition straight line segment D2.

[0015] In combination with the first aspect, in one embodiment, a chamfer is provided at a connection point between one end of the transition straight line gap section and the other end of the straight line gap section with small flanging rebound amount.

[0016] In combination with the first aspect, in one embodiment, a chamfer is provided at a connection point between the other end of the transition straight line gap section and one end of the straight line gap section with large flanging rebound amount.

[0017] In combination with the first aspect, in one embodiment, the drawing and flanging die further comprises:

[0018] A flanging punch and a flanging die, wherein a reserved groove is provided on the side of the flanging punch facing the flanging die, and the reserved groove is used to accommodate a pre-shaped transition straight line segment D2 and a pre-shaped flanging large springback straight line segment D3 formed by pre-shaping of the sheet metal part.

[0019] In a second aspect, the embodiments of the present application provide a method for controlling the springback of a sheet metal flanging using a drawing flanging die as described in some of the above embodiments, which comprises the following steps:

[0020] The sheet metal part is drawn by using a drawing punch and a drawing die. During the drawing process, the flanging section section C of the sheet metal part is pre-shaped by using a straight line gap section with a small flanging springback amount to form a pre-shaped straight line section D1 with a small flanging springback amount;

[0021] The sheet metal parts are stamped and flanging are performed using a flanging punch and a flanging die to complete the drawing and flanging process of the sheet metal parts.

[0022] In combination with the second aspect, in one embodiment, before the sheet metal part is stamped and flanging by using the flanging punch and the flanging die to complete the drawing and flanging process of the sheet metal part, the method further includes:

[0023] Cut out the stretched area of ​​the sheet metal.

[0024] The beneficial effects brought by the technical solution provided by the embodiments of the present application include:

[0025] The flange section gap section includes a straight gap section with a small amount of flange springback. One end of the gap section is connected to the flange radius gap section and gradually approaches the drawing punch along its length. This design enables the flange section section C of the sheet metal part to be pre-shaped into a pre-shaped straight line section D1 with a small amount of flange springback during the stamping process. Through the design of the straight line gap section with a small amount of flange springback, the die can pre-shape the flange part of the sheet metal part during the drawing and stamping process, thereby effectively reducing the amount of springback. The pre-shaped straight line section D1 with a small amount of flange springback after pre-shaping has a smaller springback tendency, so that the sheet metal part can more accurately maintain the shape and size required by the design after unloading. Reducing springback directly improves the dimensional accuracy and shape stability of the sheet metal part, thereby improving the overall quality of the sheet metal part. This helps to reduce the scrap rate and rework rate caused by the springback problem and reduce production costs. Compared with the traditional method of adding a side shaping process die to reduce springback, the improved technical means does not require additional die parts, thereby simplifying the die structure. This reduces mold manufacturing and maintenance costs and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 It is a structural schematic diagram of an ideal state of flanging of a sheet metal part;

[0028] Figure 2 It is a schematic diagram of the cross-sectional structure of a drawing die in the prior art;

[0029] Figure 3 It is a schematic diagram of the structure of the sheet metal part in the springback state after stamping and flanging;

[0030] Figure 4 Schematic diagram of the cross-sectional structure of the drawing die in this application;

[0031] Figure 5 This is a schematic diagram of the structure of the sheet metal part in this application after being pre-shaped by drawing with a drawing die;

[0032] Figure 6 It is a schematic diagram of the cross-sectional structure of the flanging die in this application.

[0033] In the figure: A, sheet metal plane section; B, flanged corner section; C, flanged section section; C1, straight section with small flange springback; C2, transition straight section; C3, straight section with large flange springback; D, pre-shaped flanged section section; D1, straight section with small pre-shaped flange springback; D2, pre-shaped transition straight section; D3, straight section with large pre-shaped flange springback;

[0034] 1. Sheet metal; 2. Drawing punch; 3. Drawing die; 4. Blanking gap; 41. Plane gap section; 42. Flanging radius gap section; 43. Flanging section gap section; 431. Straight line gap section with small flanging springback; 432. Transition straight line gap section; 433. Straight line gap section with large flanging springback; 5. Flanging punch; 51. Reserved groove; 6. Flanging die. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] It should be understood that flanging is a common processing method in stamping forming process. The ideal flanging state of sheet metal part 1 is as follows Figure 1 As shown, the cross-sectional shape of the sheet metal part 1 includes a sheet metal part plane section A, a flanged corner section B and a flanged cross-sectional section C. The corresponding drawing die is as follows Figure 2 As shown, due to the plastic deformation and internal stress of the sheet metal part 1 during the flanging process, springback often occurs, resulting in the size and shape of the stamped part not meeting the requirements.

[0037] Flanging springback refers to the phenomenon that when the external load is removed during the stamping process, the material in the plastic deformation zone deforms the sheet metal due to residual stress. This phenomenon is caused by the elastic recovery of the elastic deformation zone of the sheet metal and the elastic recovery of the elastic deformation part of the material in the plastic deformation zone, causing the shape and size of the sheet metal to change in the opposite direction of the deformation during loading.

[0038] This flanging springback problem is a difficult point in the sheet metal stamping process. Figure 3 As shown, the ideal state C of the flange cross-section shape becomes a straight line segment C1 with a small flange springback, a straight line segment C3 with a large flange springback, and a transition straight line segment C2 between segments C1 and C3.

[0039] Among them, the traditional solution is to add a side shaping process mold to reduce the flanging springback through side shaping. Since the sheet metal part needs to add a set of molds to add the side shaping process mold, the mold structure is complicated and the cost is increased.

[0040] The embodiment of the present application provides a drawing flanging die and a method for controlling the flanging springback of a sheet metal part, which can avoid the traditional method of adding a side shaping process die and reduce the flanging springback through side shaping. Since the sheet metal part needs to add a set of die for the side shaping process, the die structure becomes complicated and the cost increases.

[0041] First, as Figure 4 As shown, an embodiment of the present application provides a drawing and flanging die, which includes: a drawing punch 2 and a drawing die 3, a blanking gap 4 is arranged between the drawing punch 2 and the drawing die 3, the blanking gap 4 includes a plane gap section 41, a flanging corner gap section 42 and a flanging cross-sectional gap section 43 which are connected in sequence; the flanging cross-sectional gap section 43 includes a straight line gap section 431 with small flanging springback, one end of the straight line gap section 431 with small flanging springback is connected with the flanging corner gap section 42, the straight line gap section 431 with small flanging springback extends obliquely from the connection with the flanging corner gap section 42 toward the direction close to the drawing punch 2, the straight line gap section 431 with small flanging springback is used to pre-shape the flanging cross-sectional segment C of the sheet metal part 1 into a pre-shaped flanging cross-sectional segment D of a pre-shaped straight line segment D1 with small flanging springback.

[0042] In this embodiment, the mold includes a drawing punch 2 and a drawing die 3, and a blanking gap 4 is arranged between the two. The blanking gap 4 includes three parts, a plane gap section 41, a flanging radius gap section 42 and a flanging section gap section 43. This segmented design helps to more accurately control the deformation of the material during the stamping process. The flanging section gap section 43 further includes a straight line gap section 431 with a small flanging springback. One end of the gap section is connected to the flanging radius gap section 42 and gradually approaches the drawing punch 2 along its length. This design enables the flanging section section C of the sheet metal part 1 to be pre-shaped into a pre-shaped straight line section D1 with a small flanging springback during the stamping process, such as Figure 5 As shown. Through the design of the straight gap section 431 with small flanging springback, the mold can pre-shape the flanging part of the sheet metal 1 during the drawing and stamping process, thereby effectively reducing the springback amount. The pre-shaped straight segment D1 with small flanging springback after pre-shaping has a smaller springback tendency, so that the sheet metal 1 can more accurately maintain the shape and size required by the design after unloading. Reducing springback directly improves the dimensional accuracy and shape stability of the sheet metal 1, thereby improving the overall quality of the sheet metal 1. This helps to reduce the scrap rate and rework rate caused by the springback problem and reduce production costs. Compared with the traditional method of adding a side shaping process mold to reduce springback, the improved technical means does not require additional mold parts, thereby simplifying the mold structure. This reduces the manufacturing and maintenance costs of the mold and improves production efficiency. In summary, the improved technical means effectively solves the springback problem in the subsequent flanging forming process by optimizing the design of the blanking gap 4, especially the structure of the flanging section gap section 43. This not only improves the quality and production efficiency of the sheet metal part 1, but also simplifies the mold structure, reduces production costs, and enhances the adaptability of the mold.

[0043] In combination with the first aspect, in one embodiment, Figure 4 As shown, the connection between one end of the straight gap section 431 with small flanging rebound amount and one end of the flanging rounded gap section 42 is chamfered.

[0044] In this embodiment, Figure 4As shown, the connection between one end of the linear gap section 431 with a small amount of flanging rebound and one end of the flanged rounded gap section 42 is designed to be rounded. This design not only takes into account the manufacturing process of the mold, but also fully considers the stress distribution of the material during the stamping process. The rounded corner design helps the sheet metal part 1 to be smoother during the stamping process and reduces the stress concentration caused by sharp corners, which helps to improve the forming quality of the sheet metal part. Sharp corners often lead to stress concentration and increase the risk of material rupture or rebound. By adopting the rounded corner design, the stress can be effectively dispersed and these risks can be reduced, thereby improving the forming stability and dimensional accuracy of the sheet metal part 1. The rounded corner design can also reduce the wear and damage of the mold during the stamping process and extend the service life of the mold. This is because the rounded corners are less likely to produce stress concentration and wear, thereby reducing the frequency of mold maintenance and replacement. The rounded corner design is combined with the design that the linear gap section 431 with a small amount of flanging rebound gradually approaches the drawing punch 2, which further optimizes the control of rebound. This combined design can more accurately guide the deformation of the material, thereby more effectively reducing the amount of rebound. In summary, by adopting the chamfer design to connect the linear gap section 431 with small flanging springback amount and the flanging rounded corner gap section 42, stress concentration is reduced, the mold life is improved, and the control of springback is further optimized.

[0045] In combination with the first aspect, in one embodiment, Figure 4 As shown, the flanging cross-sectional gap segment 43 includes a straight gap segment 433 with large flanging springback, one end of which is connected to one end of the straight gap segment 431 with small flanging springback; the straight gap segment 433 with large flanging springback extends obliquely from the connection with the straight gap segment 431 with small flanging springback toward the direction close to the drawing punch 2, and the straight gap segment 433 with large flanging springback is used to pre-shape the flanging cross-sectional segment C of the sheet metal part 1 to form a pre-shaped straight gap segment D3 with large flanging springback of the flanging cross-sectional segment D.

[0046] In this embodiment, Figure 4 As shown, the flange cross-section gap segment 43 includes not only a linear gap segment 431 with small flange springback, but also a newly added linear gap segment 433 with large flange springback. One end of the linear gap segment 433 with large flange springback is connected with one end of the linear gap segment 431 with small flange springback, forming a continuous gap segment. Along the length direction of the linear gap segment 433 with large flange springback, and gradually away from the flange fillet gap segment 42, the gap segment gradually approaches the drawing punch 2. This design allows the flange cross-section segment C of the sheet metal part 1 to be pre-shaped by the linear gap segment 431 with small flange springback, further shaped by the linear gap segment 433 with large flange springback, and finally pre-shaped into a pre-shaped linear gap segment D3 with large flange springback, as shown in FIG. Figure 5As shown. By introducing the straight gap segment 433 with large flanging springback, segmented control of springback is achieved. First, the straight gap segment 431 with small flanging springback performs preliminary pre-shaping on the sheet metal part 1 to reduce the initial springback. Subsequently, the straight gap segment 433 with large flanging springback further shapes the sheet metal part 1 to ensure that the sheet metal part 1 can more accurately maintain the shape and size required by the design after unloading. The segmented shaping design enables each gap segment to focus more on its specific shaping task, thereby improving the accuracy and effect of the shaping. The straight gap segment 431 with small flanging springback is mainly responsible for reducing the springback of the transition straight segment C2 and the straight segment C3 with large flanging springback, while the straight gap segment 433 with large flanging springback is responsible for further reducing the springback of the straight segment C3 with large flanging springback, ensuring that the final shape and size of the sheet metal part 1 meet the requirements.

[0047] In combination with the first aspect, in one embodiment, Figure 4 As shown, the inclination angle of the straight line gap section 431 with small flanging springback is smaller than the inclination angle of the straight line gap section 433 with large flanging springback, that is, taking the length direction of the planar gap section 41 as the X-axis, and taking the stamping direction of the drawing punch 2 and the drawing die 3 as the Y-axis, the slope of the straight line gap section 431 with small flanging springback is smaller than the slope of the straight line gap section 433 with large flanging springback.

[0048] In this embodiment, Figure 4 In the figure, a coordinate system is defined with the length direction of the plane gap segment 41 as the X-axis and the stamping direction of the drawing punch 2 and the drawing die 3 as the Y-axis. In this coordinate system, the slope of the linear gap segment 431 with a small flanging springback is designed to be smaller than the slope of the linear gap segment 433 with a large flanging springback. This means that during the stamping process, the first step is to pass through a linear gap segment 431 with a small flanging springback and then pass through a linear gap segment 433 with a large flanging springback and. By designing gap segments with different slopes, such as Figure 3As shown, the smaller slope of the linear gap segment 431 with small flanging springback helps the subsequent transition linear segment C2 and the linear segment C3 with large flanging springback to have a smaller rebound compensation in the opposite direction. Subsequently, the linear gap segment 433 with large flanging springback helps the linear segment C3 with large flanging springback to further have a larger rebound compensation in the opposite direction, ensuring that the sheet metal part 1 can more accurately maintain the shape and size required by the design after unloading. The quality of the sheet metal part 1 is directly improved. The sheet metal part 1 can more accurately maintain the shape and size required by the design after unloading, reducing the scrap rate and rework rate caused by the springback problem. At the same time, the surface quality and dimensional accuracy of the sheet metal part 1 are also improved. By adjusting the slopes of the linear gap segment 431 with small flanging springback and the linear gap segment 433 with large flanging springback, different stamping conditions and sheet metal part 1 requirements can be flexibly adapted. This design makes the mold more adaptable and flexible when dealing with different materials, thicknesses and flanging requirements.

[0049] In combination with the first aspect, in one embodiment, Figure 4 and Figure 5 As shown, the flange section gap segment 43 includes a transition straight line gap segment 432, and the transition straight line gap segment 432 is connected between the straight line gap segment 431 with small flange springback and the straight line gap segment 433 with large flange springback. The transition straight line gap segment 432 is parallel to the plane gap segment 41, and the transition straight line gap segment 432 is used to pre-shape the remaining part of the flange section segment C of the sheet metal part 1 into a pre-shaped transition straight line segment D2 of the flange section segment D.

[0050] In this embodiment, a transition straight line gap section 432 is newly added in the flange cross-sectional gap section 43, which is located between the straight line gap section 431 with small flange springback and the straight line gap section 433 with large flange springback, and plays a role of connection and transition. The transition straight line gap section 432 is designed to be parallel to the plane gap section 41, which means that during the stamping process, after the material is initially pre-shaped by the straight line gap section 431 with small flange springback, it will enter a transition area parallel to the plane gap section 41, and then enter the straight line gap section 433 with large flange springback for further shaping. The main function of the transition straight line gap section 432 is to pre-shape the flange cross-sectional section C of the sheet metal part 1 to form a pre-shaped transition straight line segment D2. The introduction of the transition straight gap section 432 provides a smooth transition area for the sheet metal part 1, so that the material can be shaped more smoothly from the straight gap section 431 with a small amount of flanging rebound to the straight gap section 433 with a large amount of flanging rebound, reducing the stress concentration and uneven deformation caused by the gap change. By designing the transition straight gap section 432, the flanging rebound amount of the sheet metal part 1 can be more finely controlled. The straight gap section 431 with a small amount of flanging rebound is responsible for initially reducing the rebound, and the transition straight gap section 432 provides a stable transition area, so that the straight gap section 433 with a large amount of flanging rebound can be further shaped and rebound controlled more effectively. Smooth transition and optimized rebound control directly improve the quality of the sheet metal part 1. After unloading, the sheet metal part 1 can more accurately maintain the shape and size required by the design, reducing the scrap rate and rework rate caused by the rebound problem. The design of the transition straight gap section 432 enhances the adaptability of the mold to plates of different materials and thicknesses and different flanging requirements. By adjusting the length and gap size of the transition straight line gap section 432 , different stamping conditions and sheet metal part 1 requirements can be flexibly adapted.

[0051] In combination with the first aspect, in one embodiment, Figure 4 As shown, the connection between one end of the transition straight line gap section 432 and the other end of the flanging rebound small straight line gap section 431 is rounded.

[0052] In this embodiment, a rounded corner setting is adopted at the connection point between one end of the transition straight gap section 432 and the other end of the straight gap section 431 with small flanging rebound. This means that the connection between the two gap sections is not a sudden right-angle turn, but a smooth rounded corner transition. Such a design is intended to reduce the stress concentration and scratches that may be generated when the material passes through the connection, and ensure that the material can transition from one gap section to another more smoothly. The rounded corner setting can effectively disperse the stress generated by the material when passing through the connection, and avoid deformation or damage of the material caused by stress concentration. This helps to maintain the integrity and stability of the material and improve the quality of the sheet metal part 1. The rounded corner transition can reduce the risk of scratching the material by the mold. During the stamping process, the material may rub against the edge of the mold, and the rounded corner design can reduce this friction, thereby protecting the surface quality of the material. The rounded corner transition can reduce the wear and damage of the mold during the stamping process, thereby extending the service life of the mold. This reduces production costs and maintenance costs and improves production efficiency. By reducing stress concentration, preventing scratches and enhancing mold durability, the rounded corner setting can comprehensively improve the forming effect of the sheet metal part 1. After unloading, the sheet metal part 1 can more accurately maintain the shape and size required by the design, and the surface quality and dimensional accuracy are also significantly improved.

[0053] In combination with the first aspect, in one embodiment, Figure 4 As shown, the other end of the transition straight line gap section 432 is connected to one end of the straight line gap section 433 with large flanging rebound amount, and a rounded corner is set.

[0054] In this embodiment, the chamfer setting is also adopted at the connection point between the other end of the transition straight gap section 432 and one end of the straight gap section 433 with large flanging rebound. This means that when the material is stretched and shaped from the transition straight gap section 432 to the straight gap section 433 with large flanging rebound, it will go through a smooth rounded transition instead of a sudden right-angle turn. Similar to the rounded corner design between the transition straight gap section 432 and the straight gap section 431 with small flanging rebound, the rounded corner here can also effectively disperse the stress generated by the material when passing through the connection, further reducing the deformation or damage of the material caused by stress concentration. The rounded corner transition can significantly reduce the friction between the material and the edge of the mold when passing through the connection, thereby avoiding scratches and cracks. This is very important for maintaining the integrity of the material and improving the surface quality of the sheet metal part 1. The rounded corner transition can reduce the wear and damage of the mold during the stamping process. This helps to extend the service life of the mold and reduce production costs and maintenance costs. By reducing stress concentration, avoiding scratches and cracks, and improving the life of the mold, the rounded corner design can significantly enhance the overall forming stability of the sheet metal part 1. This enables the sheet metal component 1 to maintain its shape and size more stably after unloading, thereby improving the quality and reliability of the sheet metal component 1 .

[0055] In combination with the first aspect, in one embodiment, Figure 6 As shown, the drawing and flanging die also includes: a flanging punch 5 and a flanging die 6. A reserved groove 51 is provided on the side of the flanging punch 5 facing the flanging die 6. The reserved groove 51 is used to accommodate the pre-shaped transition straight line segment D2 and the pre-shaped flanging large springback straight line segment D3 formed by the sheet metal part 1.

[0056] In this embodiment, the drawing and flanging die includes a flanging punch 5 and a flanging die 6, which are the main working parts of the die and are used to perform flanging on the sheet metal part 1. A reserved groove 51 is specially provided on the side of the flanging punch 5 facing the flanging die 6. The design of the reserved groove 51 is very critical, and its shape and size match the pre-shaping transition straight line segment D2 and the pre-shaping flanging springback large straight line segment D3 formed after the sheet metal part 1 is pre-shaped. During the stamping process, when the sheet metal part 1 is fed into the drawing die (drawing punch 2 and drawing die 3), it will pass through the previously described flange section gap section 43 (including the linear gap section 431 with small flange springback, the transition linear gap section 432 and the linear gap section 433 with large flange springback) for pre-shaping. After pre-shaping, the sheet metal part 1 will form a pre-shaping linear segment D1 with small flange springback, a pre-shaping transition linear segment D2 and a pre-shaping linear segment D3 with large flange springback. Subsequently, when the subsequent flanging dies (flanging punch 5 and flanging die 6) are closed, the flanging punch 5 and the flanging die 6 are closed. The concave die 6 will act together on the rounded corner section B of the flanging and the straight section C1 with small flanging springback of the sheet metal part 1, while the reserved groove 51 will accurately accommodate the pre-shaped transition straight section D2 and the pre-shaped flanging springback straight section D3. The design of the reserved groove 51 makes the flanging forming process more precise. It can ensure that the pre-shaped sheet metal part 1 avoids deformation during the forming process. The reserved groove 51 accommodates the pre-shaped transition straight section D2 and the pre-shaped flanging springback straight section D3, thereby preventing the pre-shaped transition straight section D2 and the pre-shaped flanging springback straight section D3 from flanging.

[0057] In combination with the first aspect, in one embodiment, Figure 5 As shown, the sheet metal part 1 may be a front fender of an automobile. If the maximum rebound amount of the straight line segment D3 with a large rebound amount of the pre-shaped flange is a, the straight line segment D3 with a large rebound amount of the pre-shaped flange is compensated for rebound in the opposite direction of the rebound direction, and the compensation amount a1 = (1.05~1.1)*a.

[0058] Combined with the first aspect, in one embodiment, the width dimension of the pre-shaping flange springback large straight line segment D3 is obtained according to the finite element analysis (FEA) software. For example, when the flange height of the flange section segment C of the front dash panel is 20.5 mm, according to the finite element analysis (FEA) software analysis, the width dimension of the straight line gap segment 433 with large flange springback is about 12 mm. According to the empirical value, the width dimension of the transition straight line gap segment 432 is within the range of 2 to 3 mm, and its line segment is also horizontal with the sheet metal plane segment A. The width dimension of the straight line gap segment 431 with small flange springback is 20.5-12-3=5.5 mm, and the angle between the straight line gap segment 431 with small flange springback and the horizontal line is 10° to 12°. The purpose of taking the angle between the straight line gap segment 431 with small flange springback and the horizontal line as 10° to 12° here is to stretch and pre-form the material at the flange, which is beneficial to the freezing of the part shape after the later flanging.

[0059] In combination with the first aspect, in one embodiment, Figure 4 As shown, the chamfer R1 between the flange rounded gap section 42 and the straight gap section 431 with small flange rebound amount can be 1 to 2 mm, the chamfer R2 between the straight gap section 431 with small flange rebound amount and the transition straight gap section 432 can be 5 to 6 mm, and the chamfer R3 between the transition straight gap section 432 and the straight gap section with large flange rebound amount can be 1 to 2 mm.

[0060] In combination with the first aspect, in one embodiment, Figure 6 As shown, the flanging gap between the flanging punch 5 and the flanging die 6 is changed from the original uniform gap (1.0 times the material thickness t) to a variable gap. Starting from the tangent point of the flanging radius section B to the pre-shaping flanging springback small straight line section D1, the flanging gap is 1.0 times the material thickness. Starting from the pre-shaping transition straight line section D2, the flanging gap increases to S, forming a reserved groove 51. The flanging gap is increased here to ensure that when the flanging punch 5 is in the working state to the bottom dead center, the pre-shaping transition straight line section D2 and the pre-shaping flanging springback large straight line section D3 that have been drawn and compensated for the flanging springback are not squeezed into a straight edge state by the flanging gap of 1.0 times the material thickness t. Here, the pre-shaping transition straight line section D2 and the pre-shaping flanging springback large straight line section D3 in the open state are released after the flanging punch returns and the flanging action is completed, and the pre-shaping transition straight line section D2 and the pre-shaping flanging springback large straight line section D3 rebound to a reasonable range.

[0061] In a second aspect, an embodiment of the present application provides a method for controlling the springback of a sheet metal flanging using a drawing flanging die as described in some of the above embodiments, which comprises the following steps:

[0062] S1: The sheet metal part 1 is drawn by using the drawing punch 2 and the drawing die 3. During the drawing process, the flanging cross-section section C of the sheet metal part 1 is pre-shaped into a pre-shaped flanging springback small straight line section D1 by using the flanging springback small straight line gap section 431;

[0063] S3: The sheet metal part 1 is punched and flanginged using the flanging punch 5 and the flanging die 6 to complete the drawing and flanging process of the sheet metal part 1 .

[0064] In this embodiment, S1 uses a drawing punch 2 and a drawing die 3 to draw the sheet metal part 1. During the drawing process, the flanging section section C of the sheet metal part 1 is pre-shaped by using the linear gap section 431 with a small flanging springback amount, so as to form a pre-shaped linear section D1 with a small flanging springback amount. The purpose of this step is to preliminarily control the flanging springback through pre-shaping and to prepare for the subsequent flanging process. S3 uses a flanging punch 5 and a flanging die 6 to stamp and flanging the sheet metal part 1. During the stamping process, the reserved groove 51 on the flanging punch 5 will accurately accommodate the remaining part of the sheet metal part 1. Through the close cooperation of the flanging punch 5 and the flanging die 6, the drawing and flanging process of the sheet metal part 1 is completed to form the final flanging shape.

[0065] In conjunction with the second aspect, in one implementation, before S3, the following steps are included:

[0066] S2: Cutting the stretched area of ​​sheet metal part 1.

[0067] In this embodiment, after the drawing pre-shaping is completed, S2 cuts the sheet metal part 1 to remove unnecessary parts and retain the area segment for flanging processing. The cutting can be completed by a cutting knife on the mold or a separate cutting process to ensure that the size and shape of the cut sheet metal part meet the requirements of the subsequent flanging processing. The purpose of this step is to optimize material utilization, reduce unnecessary material waste, and prepare the shape of the sheet metal part 1 suitable for flanging processing.

[0068] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0069] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0070] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A drawing and flanging die, characterized in that: It includes: A drawing punch (2) and a drawing die (3), wherein a blanking gap (4) is provided between the drawing punch (2) and the drawing die (3), and the blanking gap (4) comprises a plane gap section (41), a flanged corner gap section (42) and a flanged cross-section gap section (43) which are connected in sequence; The flanging cross-sectional gap section (43) comprises a straight line gap section (431) with small flanging springback, one end of which is connected to the flanging rounded corner gap section (42), and the straight line gap section (431) with small flanging springback extends obliquely from the connection with the flanging rounded corner gap section (42) toward the direction close to the drawing punch (2), and the straight line gap section (431) with small flanging springback is used to pre-shape the flanging cross-sectional section C of the sheet metal part (1) to form a pre-shaped straight line section D1 with small flanging springback.

2. The drawing and flanging die according to claim 1, characterized in that: The connection between one end of the straight gap section (431) with a small amount of flanging rebound and one end of the flanging rounded gap section (42) is arranged in a rounded shape.

3. The drawing and flanging die according to claim 1, characterized in that: The flange cross-section gap section (43) comprises a linear gap section (433) with a large flange springback amount, and one end of the linear gap section (433) with a large flange springback amount is connected to one end of the linear gap section (431) with a small flange springback amount; The straight line gap section (433) with large flanging springback extends obliquely from the connection with the straight line gap section (431) with small flanging springback toward the direction close to the drawing punch (2), and the straight line gap section (433) with large flanging springback is used to pre-shape another part of the flanging cross-section section C of the sheet metal part (1) to form a pre-shaped straight line section D3 with large flanging springback.

4. The drawing and flanging die according to claim 3, characterized in that: The inclination angle of the linear gap section (431) with a small amount of flanging rebound is smaller than the inclination angle of the linear gap section (433) with a large amount of flanging rebound.

5. The drawing and flanging die according to claim 3, characterized in that: The flange cross-sectional gap segment (43) further includes a transition straight line gap segment (432), wherein the transition straight line gap segment (432) is connected between the straight line gap segment (431) with small flange springback and the straight line gap segment (433) with large flange springback, and the transition straight line gap segment (432) is parallel to the plane gap segment (41). The transition straight line gap segment (432) is used to pre-shape the remaining part of the flange cross-sectional segment C of the sheet metal part (1) into a pre-shaped transition straight line segment D2.

6. The drawing and flanging die according to claim 5, characterized in that: The connection between one end of the transition straight line gap section (432) and the other end of the straight line gap section (431) with small flanging rebound amount is provided with a rounded corner.

7. The drawing and flanging die according to claim 5, characterized in that: The point where the other end of the transition straight line gap section (432) is connected to one end of the straight line gap section (433) with large flanging rebound amount is rounded.

8. The drawing and flanging die according to claim 5, characterized in that: The drawing and flanging die also includes: A flanging punch (5) and a flanging die (6), wherein a reserved groove (51) is provided on a side of the flanging punch (5) facing the flanging die (6), and the reserved groove (51) is used to accommodate a pre-shaped transition straight line segment D2 and a pre-shaped straight line segment D3 with a large amount of flanging rebound formed by pre-shaping of the sheet metal part (1).

9. A method for controlling the springback of a sheet metal flanging using the drawing flanging die according to any one of claims 1 to 8, characterized in that: It includes the following steps: The sheet metal part (1) is drawn using a drawing punch (2) and a drawing die (3). During the drawing process, the flanging cross-section section C of the sheet metal part (1) is pre-shaped using a flanging springback small linear gap section (431) to form a pre-shaped flanging springback small linear section D1; The sheet metal part (1) is punched and flanging performed using a flanging punch (5) and a flanging die (6), thereby completing the drawing and flanging process of the sheet metal part (1).

10. The method for controlling the springback of a sheet metal flanging of a drawing flanging die according to claim 9, characterized in that: Before the sheet metal part (1) is stamped and flanging is performed using the flanging punch (5) and the flanging die (6) to complete the drawing and flanging process of the sheet metal part (1), the method further comprises: Cutting the stretched area of ​​the sheet metal part (1).

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