A stamping method for aluminum rear door outer panel of automobile

Abstract

This invention relates to a stamping method for an aluminum rear door outer panel for automobiles, comprising the following five steps: drawing, with a supplementary process design for the B-pillar position of the rear door outer panel to achieve a shallow shell state; trimming, sequentially removing waste material around the product; first shaping, designed as a clamping shaping process, not directly shaping to the finished product state, but shaping to the over-drawn state; second shaping, shaping from the finished part state of the first shaping process to the stepped surface state of the product; and flanging, either straight flanging at 0 degrees according to the stamping direction or oblique flanging designed according to the pressing angle requirements, to complete the stamping of the aluminum rear door outer panel. This invention's stamping method for aluminum rear door outer panels for automobiles, through the design of a supplementary process for a shallow shell shape and two shaping processes—the first clamping shaping to the over-drawn state and the second straight shaping to the finished product—solves the problem of cracking and wrinkling on the stepped surface of the B-pillar of the aluminum rear door outer panel, provides better springback control, and achieves superior surface quality.

Description

Technical Field

[0001] This invention belongs to the field of automobile manufacturing technology, specifically relating to a stamping method for an aluminum rear door outer panel of an automobile. Background Technology

[0002] With the development of lightweight technology, aluminum sheets are being used more and more widely in automotive exterior body panels. However, the problems associated with aluminum sheet stamping are also becoming increasingly prominent. In particular, for exterior parts such as hoods and door panels, the poor formability of aluminum sheets limits the design of exterior feature lines. Figure 1 This is a product drawing of an aluminum rear door exterior panel. The overlap between the B-pillar and the rear end of the front door is designed as a stepped surface, i.e., the B-pillar step surface. A partial cross-section of the B-pillar step is shown below. Figure 2 As shown, the step fillet R1 is the appearance fillet, typically around R1.2mm-1.7mm for steel parts and R2.5mm-3mm for aluminum parts. The draft angle of the step sidewall is set according to the springback angle, typically 3 degrees for steel parts and 5 degrees for aluminum parts. The step fillet R2 is typically 2mm-3mm for steel parts and 2.5mm-5mm for aluminum parts. The step depth H is typically 10mm-12mm. When the feature edge is sharp, the step depth at the corresponding position is generally about 1mm deeper than other positions. Due to the small fillet, small draft angle, and deep depth of the B-pillar step, and the even deeper step depth at the feature edge position, the step cannot be directly formed by drawing; it must be shaped to achieve the product feature, and the sharp points of the feature edge are prone to cracking.

[0003] Currently, there are two main process solutions used in the industry. One is to overdraw the B-pillar step during the drawing process and then shape it into the product. The advantage of this solution is that cracking can be improved by adjusting the overdrawing parameters. The disadvantage is that the greater the difference between the overdrawing parameters and the product, the more likely wrinkling will occur, and the surface finish and springback will also be worse. Moreover, excessive thickening during shaping can easily cause cracking at the sharp edges. The other solution is to design the B-pillar step as a shallow shell shape with a depth of about 2mm, which is shifted upwards from the product step surface. During the subsequent shaping process, the material is clamped and shaped into the product step by increasing the pressure material. The advantage of this solution is that the surface finish, wrinkling, and springback are better controlled. The disadvantage is that pulling the material during clamping can easily cause cracking at the sharp edges, especially since aluminum sheet material has poor formability, making the cracking problem more prominent. Summary of the Invention

[0004] The purpose of this invention is to provide a stamping method for aluminum rear door outer panels of automobiles, so as to solve the problems of severe wrinkling during the shaping of the stepped surface where the B-pillar of the rear door outer panel overlaps with the front door, as well as the cracking of the characteristic edge points and the sidewalls of the stepped surface on the outer panel.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A stamping method for an aluminum rear door outer panel for automobiles includes the following five steps:

[0007] Step S1, drawing, the drawing process of the B-pillar position of the rear door outer panel is designed as a process supplement to the shallow shell state;

[0008] Step S2: Trim the edges and remove waste material around the product in sequence;

[0009] Step S3, the first shaping, is designed as clamping shaping, not directly shaping to the product state, but shaping to the over-drawing state of the product;

[0010] Step S4, second shaping, shaping from the state of the workpiece after the first shaping to the state of the product step surface;

[0011] Step S5, Flanging: Flanging is done by straight flanging at 0 degrees in the stamping direction or by designing a slanted flanging according to the pressing angle requirements, to complete the stamping of the aluminum rear door outer panel product.

[0012] Further, in step S1, the supplementary surface of the shallow shell process is obtained by shifting the product step surface upward by 8mm-11.5mm along the stamping direction of the first forming process. This ensures that the shallow shell surface is about 0.5mm-5mm deep from the product A surface. It should be noted that the depth of the shallow shell surface obtained by shifting the product step surface upward is different from that of the A surface. They are not the same depth. The depth of the shallow shell surface obtained by shifting the product step surface upward is about 0mm-3mm deeper than that of the other parts. Therefore, the local step surface corresponding to the feature edge position can be shifted upward by 0mm-3mm more than that of the other parts, and then smoothly connected with other parts to avoid cracking during drawing.

[0013] Further, in step S1, the design parameters of the supplementary surface of the shallow shell drawing process are as follows: R3 can be designed as R6mm-R15mm, preferably R10mm; R4 can be designed as R10mm-R50mm, wherein R4-1 is preferably designed as R20mm; R4-2 corresponds to the tip of the feature edge, which is prone to cracking during drawing, and is preferably designed as R35mm; large rounded corner process allowance is set on the outside of the shallow shell, and allowance R5 can be designed as R20mm-R50mm, preferably R30mm; allowance R6 can be designed as R20mm-R50mm, preferably R30mm; the height of the allowance corresponding to the feature edge is designed to be 1mm-2mm higher than the feature edge of the product, ensuring that the thinning rate of drawing is preferably controlled within 12%, and the maximum does not exceed 14%; the drawing depth h2 is designed according to the overall product shape, and is generally 30mm-70mm deep.

[0014] Furthermore, in step S2, waste material around the product is removed in sequence, with the trimming angle controlled within 15 degrees. The obtuse trimming angle can be up to 18 degrees depending on the situation.

[0015] Furthermore, in step S3, the parameters for the first clamping and shaping to the over-drawing state of the product are designed as follows: R7 can be designed as R4mm-R8mm, preferably R5mm; R8 can be designed as R4mm-R12mm, preferably R5mm; the sidewall draft angle can be designed as 0 degrees-5 degrees, preferably 1 degree. The specific shaping parameter values ​​are adjusted according to the cracking state analyzed in the simulation to ensure that the final product thinning value is within 25%. For example, if the product thinning is about 20% after the first clamping and shaping, it is necessary to ensure that the sheet elongation is controlled within 5% when shaping the product in the second subsequent step, that is, (product line length - first shaping line length) / first shaping line length < 5%.

[0016] Furthermore, in step S3, the stroke of the lower pressure plate for the first clamping and shaping is set according to the translation stroke of the shallow shell surface during drawing. The position corresponding to the non-feature edge can be directly shaped to the product step surface, while the position corresponding to the feature edge, the distance h between the first shaping step surface and the product step surface can be designed to be 0-2mm. h should not exceed 2mm as much as possible, otherwise there is a risk of wrinkling.

[0017] Furthermore, in step S3, the power source for the lower movable pressure plate of the first clamping and shaping is a delayed nitrogen cylinder to prevent the lower pressure plate from lifting up during the return stroke of the upper mold, which would cause the workpiece to be deformed.

[0018] Furthermore, in step S4, the second shaping involves designing the product step wall as a 0-degree straight shaping to ensure that the product step wall meets a 5-degree draft angle after springback, while avoiding surface defects caused by angular shaping.

[0019] Furthermore, in step S5, the flanging design is a straight flanging at 0 degrees in the stamping direction or an oblique flanging designed according to the pressing angle requirements. The radius of the flanging punch R9 is generally 1mm-1.5mm, designed according to the actual flanging cracking situation and pressing requirements. The radius of the flanging die R10 is generally designed to be 2mm-3mm. For non-clamping flanging, R2mm is preferred, and for clamping flanging, R2.5mm is preferred. For the flanging at the B-pillar position of the rear door outer panel, non-clamping flanging is preferred.

[0020] Furthermore, the shaping and flanging processes in steps S4 and S5 can be designed to be implemented in one process, with the intermediate shaping using a movable pressure plate, saving one process.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The present invention relates to a stamping method for aluminum rear door outer panels of automobiles. By designing a process supplement of drawing shallow shell shape and two forming processes, the first forming process is to clamp and shape the material to the over-drawing state of the product, and the second forming process is to directly shape the product. This solves the problem of cracking and wrinkling on the B-pillar step surface of the aluminum rear door outer panel, has better springback control, and can obtain better surface quality. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 Structural diagram of the outer aluminum rear door panel of a certain automobile;

[0025] Figures 2-3 Enlarged view and cross-sectional view of the rear door outer panel;

[0026] Figures 4-5 Schematic diagram of the partial stamping process for the B-pillar of the rear door outer panel;

[0027] Figures 6-7 Partial schematic diagram and cross-sectional view of the B-pillar of the rear door outer panel drawing process;

[0028] Figure 8 Schematic diagram of the partial trimming process of the rear door outer panel;

[0029] Figure 9 Schematic diagram of the partial trimming process of the rear door outer panel;

[0030] Figures 10-11 A partial schematic diagram and cross-sectional view of the first clamping and shaping process of the rear door outer panel;

[0031] Figure 12 Schematic diagram of the first clamping and shaping process of the rear door outer panel;

[0032] Figures 13-14 Schematic diagram of secondary straightening and flanging of the rear door outer panel. Detailed Implementation

[0033] The present invention will be further described below with reference to embodiments:

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0035] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] This invention primarily addresses the stamping process for the stepped surface where the rear door outer panel overlaps with the front door at the B-pillar position. This stepped surface is visible when the front door is opened, thus requiring high quality. To avoid severe wrinkling during the forming process and to prevent sharp edges on the door outer panel and cracking of the stepped sidewalls, a new stamping process method is proposed. Figures 4-5 As shown, it includes the following steps:

[0037] 1. Drawing: During the drawing process at the B-pillar position, a shallow shell is created. The shallow shell shape is achieved by shifting the product's stepped surface upwards along the stamping direction of the first forming process, ensuring an overall shallow shell depth of 0.5mm-5mm. The specific design of the shallow shell surface can be adjusted appropriately based on the thinning state during drawing. Large rounded corners are provided on the outside of the shallow shell, and the height of the excess material corresponding to the feature edges is 1mm-2mm higher than the product's feature edges to protect the edge tips from contacting the material in the initial stage of drawing. The principle is to delay the edge tips from contacting the material as much as possible, ensuring that the thinning rate is preferably controlled within 12%, and at most not exceeding 14%.

[0038] 2. Trim the edges, removing waste material around the product in sequence.

[0039] 3. The first shaping process is designed as clamping shaping. To optimize cracking issues, the first clamping shaping does not directly shape the product to its final state, but rather shapes it to the over-drawn state, such as... Figures 4-5 As shown, the specific shaping parameter values ​​are designed based on the actual cracking state analysis to ensure that the final product thinning value is within 25%. The stroke of the lower pressure plate is set according to the translation stroke of the shallow shell surface during drawing. The final shaping state is shown in the figure. The distance h between the local shaping step surface at the corresponding position of the feature edge and the product step surface is generally 0-2mm, and should not exceed 2mm as much as possible, otherwise there is a risk of wrinkling.

[0040] 4. Second shaping: Shape the workpiece from the state of the workpiece after the first shaping to the product state. Note that the shaping step wall is designed to be straight at 0 degrees to ensure that the product meets the 5-degree draft angle after springback, while avoiding surface defects caused by angular shaping.

[0041] 5. Flanging: Flanging at 0 degrees in the stamping direction or designing a slanted flange according to the pressing angle requirements.

[0042] Specifically, the stamping method for the outer aluminum rear door panel of an automobile of the present invention includes the following steps:

[0043] Step S1, drawing, as follows Figures 6-7The diagram shows a partial schematic and cross-sectional view of the B-pillar component in the rear door outer panel drawing process. The diagram illustrates a shallow shell state during the drawing process of the B-pillar. The shallow shell surface is shifted upwards by 8mm-11.5mm along the stamping direction of the first forming process, ensuring the depth h1 between the shallow shell surface and the product A-side is approximately 0.5mm-5mm. It's important to note that the product step depth H is obtained by offsetting the product A-side extension surface, which differs from the stamping direction during forming. Therefore, when the product step surface is shifted upwards along the stamping direction, the depth h1 between the resulting shallow shell surface and the A-side varies; they are not equal in depth. At the feature edge position, the shallow shell surface is locally 0mm-3mm deeper than other positions. Therefore, the local step surface corresponding to the feature edge position can be shifted upwards by 0mm-3mm more than other positions, and then smoothed with other parts to avoid drawing cracks. The specific design of the shallow shell surface can be adjusted appropriately based on the thinning state during drawing. Among them, R3 can be designed to be R6mm-R15mm, preferably R10mm, and R4 can be designed to be R10mm-R50mm. R4-1 is preferably designed to be R20mm. R4-2 corresponds to the sharp point of the feature edge, which is prone to cracking during drawing; therefore, it is preferably designed to be R35mm. A large rounded corner is provided on the outer surface of the shallow shell as processing allowance. Allowance R5 can be designed to be R20mm-R50mm, preferably R30mm. Allowance R6 can be designed to be R20mm-R50mm, preferably R30mm. The allowance height corresponding to the feature edge is designed to be 1mm-2mm higher than the feature edge of the product to protect the edge tip from contacting the material in the initial stage of drawing. The principle is to delay the edge tip contacting the material as much as possible, ensuring that the thinning rate is preferably controlled within 12%, with a maximum not exceeding 14%. The drawing depth h2 is designed according to the overall product shape, generally 30mm-70mm deep.

[0044] Step S2, trimming: Remove waste material around the product in sequence, such as... Figure 8 , Figure 9 As shown, the trimming angle should be controlled within 15 degrees, and the obtuse angle trimming angle can be up to 18 degrees depending on the situation.

[0045] Step S3, first shaping, designed as clamping shaping, such as... Figures 10-11 The image shown is a partial schematic diagram and cross-sectional view of the part during the first shaping process. Figure 12 This is a cross-sectional diagram of the first clamping and shaping process. To optimize cracking issues, the first clamping and shaping does not directly shape the product to its final state, but rather shapes it to the over-drawn state. For example... Figures 10-11As shown, R7 can be designed from R4mm to R8mm, preferably R5mm, and R8 can be designed from R4mm to R12mm, preferably R5mm. The draft angle of the side wall can be designed from 0 degrees to 5 degrees, preferably 1 degree. The specific forming parameter values ​​are adjusted according to the cracking state of the simulation analysis to ensure that the thinning value of the final product is within 25%. For example, if the product thins by about 20% after the first forming, it is necessary to ensure that the sheet elongation is controlled within 5% when forming the product in the second subsequent forming, i.e., (product line length - first forming line length) / first forming line length < 5%. The stroke of the lower pressure plate is set according to the translation stroke of the shallow shell surface during drawing. The position corresponding to the non-feature edge can be directly formed to the product step surface, i.e., the h value in the figure is 0mm. For the position corresponding to the feature edge, the distance h between the first forming step surface and the product step surface can be designed to be 0-2mm. h should not exceed 2mm as much as possible, otherwise there is a risk of wrinkling. The power source of the lower movable pressure plate is a delayed nitrogen cylinder to prevent the lower pressure plate from being lifted up during the return stroke of the upper die, which would cause the part to be deformed.

[0046] Step S4, second plastic surgery, as follows Figures 13-14 As shown, from the process state of the workpiece after the first forming to the product state, the product step wall is designed to be straight with a 0-degree angle to ensure that the product step wall meets the 5-degree draft angle state after springback, while avoiding surface defects caused by forming with an angle.

[0047] Step S5, flip the edge, as shown Figures 13-14 As shown, a straight flanging with a 0-degree angle is designed according to the stamping direction or a slanted flanging according to the pressing angle requirements. The radius of the flanging punch R9 is generally 1mm-1.5mm, designed according to the actual flanging cracking situation and pressing requirements. The radius of the flanging die R10 is generally designed to be R2mm-3mm. R2mm is preferred for non-clamping flanging and R2.5mm is preferred for clamping flanging. Non-clamping flanging is preferred for flanging at the B-pillar position of the rear door outer panel.

[0048] The second shaping and final flanging can be designed to be completed in one process, using a movable pressure plate for shaping in the middle, saving one process. This invention solves the problem of cracking and wrinkling on the B-pillar step surface of the aluminum rear door outer panel by designing a process supplement for the shallow shell shape of the drawing process and a two-stage shaping process (the first shaping is done by clamping the material to the product over-drawing state, and the second shaping is done directly to the product). It also has better control over springback and can achieve better surface quality.

[0049] Example 1

[0050] A partial cross-section of the B-pillar step of a certain aluminum rear door outer panel product is shown below. Figures 2-3 As shown, the step fillet R1 is R3mm, the step sidewall draft angle is 5 degrees, the step fillet R2 is R4mm, the step depth H at the non-feature edge position is 10mm, and the step depth H at the corresponding position of the feature edge is 11mm.

[0051] The specific stamping process for this aluminum rear door outer panel includes the following steps (taking a portion of the B-pillar step surface as an example):

[0052] 1. First process: drawing, such as Figures 6-7 The diagram shows a partial schematic and cross-sectional view of the B-pillar part in the back door outer panel drawing process. The diagram shows the shallow shell state of the B-pillar part during the drawing process. The shallow shell surface is shifted upward by 8mm along the stamping direction of the first forming process, with the product step surface. The feature ridge line is shifted upward by 9mm along the local product step surface. The depth h1 of the resulting shallow shell surface from the product A surface is 2mm-3mm. R3 is designed as R10mm, R4-1 as R20mm, and R4-2 as R35mm. Large rounded corner process allowance is set on the outside of the shallow shell. The allowance R5 is designed as R30mm, and the allowance R6 is designed as R30mm. The height of the allowance corresponding to the feature ridge line is designed to be 1mm higher than the feature ridge line of the product to protect the ridge tip from contacting the material in the initial stage of drawing. The final part has the maximum thinning rate of 13% at the ridge tip position. The drawing depth h2 is designed to be 40-50mm.

[0053] 2. Second step: Straight edge trimming, such as... Figure 8 The diagram shown is a partial schematic diagram and a partial cross-sectional view of the B-pillar component in the second process of the rear door outer panel. This process removes waste material within a 15-degree straight repair angle from the outer ring of the product.

[0054] 3. Third step: Straight edge trimming + bevel edge trimming, such as... Figure 9 The image shows a partial schematic diagram and a partial cross-sectional view of the B-pillar component in the three-stage process of the rear door outer panel, with the remaining waste material around the product removed.

[0055] 4. Fourth process: First shaping, designed as clamping shaping, such as... Figures 10-11 The image shown is a partial schematic diagram and cross-sectional view of the part during the first shaping process. Figure 12 This is a cross-sectional diagram of the first clamping and shaping process. To optimize cracking issues, the first clamping and shaping does not directly shape the product to its final state, but rather shapes it to the over-drawn state. Figures 10-11 As shown, R7 is designed to be R5mm, R8 is designed to be R5mm, the side wall draft angle is designed to be 1 degree, the sheet metal elongation is 2.4%, the product thinning rate after the first clamping and shaping is a maximum of 18%, the lower pressure plate stroke is 8mm, the position corresponding to the non-feature edge is directly shaped to the product step surface, that is, the h value in the figure is 0mm, while the position corresponding to the feature edge, the distance h between the first shaping step surface and the product step surface is 1mm. The power source of the lower movable pressure plate is a delayed nitrogen cylinder to avoid the lower pressure plate being lifted up when the upper mold returns, which would cause the part to be deformed.

[0056] 5. Fifth step: Second shaping + flanging, such as... Figures 13-14As shown, the product's stepped wall is designed with a 0-degree straight forming to ensure that the product's stepped wall meets a 5-degree draft angle after springback, while avoiding surface defects caused by angular forming. The flanging adopts a 0-degree straight flanging, which is not clamping flanging. The flanging punch radius R9 is 1.5mm, and the flanging die radius R10 is 2mm. After the final forming and flanging, the maximum thinning of the product is 20% at the tip of the feature edge, and it is in a bi-directional stretching state, which meets the design standards for aluminum plate parts.

[0057] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A stamping method for an aluminum rear door outer panel for automobiles, characterized in that, It includes the following five steps: Step S1, drawing, the drawing process of the B-pillar position of the rear door outer panel is designed as a shallow shell state, forming a drawing shallow shell process supplementary surface; Step S2: Trim the edges and remove waste material around the product in sequence; Step S3, the first shaping, is clamping shaping. It does not directly shape the product to the product state, but shapes the product to the over-drawing state. Step S4, second shaping, shaping from the state of the workpiece after the first shaping to the state of the product step surface; Step S5, Flanging: Flanging straight at 0 degrees in the stamping direction or designing a slanted flange according to the pressing angle requirements to complete the stamping of the aluminum rear door outer panel product. In step S1, the supplementary surface of the shallow shell drawing process is obtained by shifting the product step surface upward by 8mm-11.5mm along the stamping direction of the first forming process, ensuring that the shallow shell drawing surface is 0.5mm-5mm deep from the product A surface. The local step surface corresponding to the feature edge position is shifted upward by 0mm-3mm more than other positions, and is smoothly connected with other parts. In step S3, the stroke of the lower pressure plate for the first clamping and shaping is set according to the translation stroke of the shallow shell surface during drawing. The position corresponding to the non-feature edge can be directly shaped to the product step surface, while the position corresponding to the feature edge, the distance h between the first shaping step surface and the product step surface is 0-2mm. In step S3, the power source for the lower movable pressure plate of the first clamping and shaping is a delayed nitrogen cylinder; In step S4, the second shaping process involves straightening the product steps at a 0-degree angle.

2. The stamping method for an aluminum rear door outer panel of an automobile according to claim 1, characterized in that: In step S1, the parameters of the supplementary surface of the shallow shell drawing process are as follows: R3 is R6mm-R15mm, R4 is R10mm-R50mm, excess material R5 is R20mm-R50mm, excess material R6 is R20mm-R50mm, and the height of the excess material corresponding to the feature edge is designed to be 1mm-2mm higher than the feature edge of the product to ensure that the thinning rate of drawing is controlled within 12%, and the maximum does not exceed 14%. The drawing depth h2 is designed according to the overall shape of the product and is 30mm-70mm deep.

3. The stamping method for an aluminum rear door outer panel of an automobile according to claim 1, characterized in that: In step S2, waste material around the product is removed in sequence, and the trimming angle is controlled within 15 degrees. The obtuse angle trimming angle can be up to 18 degrees depending on the situation.

4. The stamping method for an aluminum rear door outer panel of an automobile according to claim 1, characterized in that: In step S3, the first clamping and shaping process is carried out until the product is in the over-drawing state. The parameters are as follows: R7 is R4mm-R8mm, R8 is R4mm-R12mm, the side wall draft angle is 0 degrees-5 degrees, and the shaping parameter values ​​are adjusted according to the cracking state of the simulation analysis to ensure that the final product thinning value is within 25% and the sheet elongation is controlled within 5%.

5. The stamping method for an aluminum rear door outer panel of an automobile according to claim 1, characterized in that: In step S5, the flanging is a straight flanging at 0 degrees in the stamping direction or a slanted flanging designed according to the pressing angle requirements. The radius R9 of the flanging punch is 1mm-1.5mm. Depending on the actual flanging cracking situation and pressing requirements, the radius R10 of the flanging die is 2mm-3mm. The non-clamping flanging is R2mm, the clamping flanging is R2.5mm, and the flanging at the B-pillar position of the rear door outer panel is a non-clamping flanging.

6. The stamping method for an aluminum rear door outer panel of an automobile according to claim 1, characterized in that: The shaping and flanging processes in steps S4 and S5 can be designed to be completed in one process. The intermediate shaping is carried out using a movable pressure plate, which saves one process.

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