A drawing slab clamping structure and slab shrinkage control optimization method

Abstract

The present invention discloses a drawing plate pressing structure, wherein the mating surface between the drawing die and the drawing press forms a pressing surface group, and the pressing surface group comprises an outer guide part, a drawing rib pressing part and an inner guide part connected sequentially from the outside to the inside, wherein the drawing rib pressing part is a pair of mutually matched arc surfaces facing each other, used to press the plate processed by the drawing die, and provide flow resistance of the plate, and the inner guide part and the outer guide part are both mutually matched plane surfaces, and the surface gap D1 of the inner guide part and the surface gap D2 of the outer guide part respectively satisfy the following relationship with the plate thickness T: T+0.05mm≤D1≤T+0.1mm; T+0.05mm≤D2≤T+0.1mm. The present invention also provides a plate shrinkage control optimization method. The present invention has the beneficial effects that the dimensional deviation redundancy of the mold pressing surface is greatly improved, and the coating requirements of the pressing surface are greatly reduced, which greatly reduces the difficulty and workload of mold debugging, and at the same time ensures the working life of the mold, thereby reducing the mold cost as a whole.

Description

Technical Field

[0001] The invention belongs to the field of stamping technology, and in particular relates to a drawn slab clamping structure and a slab shrinkage control optimization method. Background Art

[0002] Drawing is a widely used stamping production method, which is widely used in the production of automobile body parts. Traditional production uses more steel sheets. In recent years, aluminum alloy light materials have also been used in automobile body parts. Drawing is carried out using a drawing die, which is used to process the slab into a product blank with a general shape. During the drawing process, the slab is pressed by the drawing die and the blank holder to provide flow resistance of the slab and control the flow speed of the sheet within an appropriate range, so as to obtain a qualified product with a good appearance. The pressing and fitting surface between the drawing die and the blank holder includes an air avoidance area from outside to inside, a non-functional surface pressing part, a draw rib pressing part and a functional surface pressing part. Among them, the gap of the functional surface pressing part is equal to the thickness T of the slab to be processed, the gap of the non-functional surface pressing part is not less than T and not greater than the gap of the air avoidance area, and the gap of the air avoidance area is T~T+1mm. The friction force of the functional surface pressing part and the convex arc surface of the draw rib on the slab is the main source of resistance to material flow. The functional clamping surface and the non-functional clamping surface are very sensitive to the gap. Every increase or decrease of 0.01 mm in the gap will greatly increase or decrease the resistance.

[0003] However, the actual slab thickness tolerance is 3% to 5% of the material thickness. The drawn slab will also wrinkle during the flow process, and the local thickness of the drawn slab will increase. This poses a great challenge to the functional clamping surface and the non-functional clamping surface. It is necessary to ensure that the mating surfaces are evenly fitted, with high surface hardness and high surface roughness.

[0004] Appearance defects such as cracking, necking, and roughening often occur, making the mold debugging cost very high. In addition, surface coating treatment is required to ensure the stability of mass production. Since the coating cost is higher than the mold insert material cost, coating treatment greatly increases the equipment cost.

[0005] Specifically, the main reasons for the difficulty in mold debugging are: first, the early drawing die is assembled and debugged at the mold supplier, while mass production is carried out on the stamping machine in the stamping factory. The two ejector pins are inconsistent, and the parallelism of the upper slider and the work table has a difference of more than plus or minus 0.1 mm. This difference requires the mold fitter to use red lead or blue lead to color and check the gap between the pressing surfaces to ensure it. This work needs to be done twice, and it is completely dependent on the personal experience of the mold fitter, making debugging difficult. Since the flow resistance of the drawn slab is controlled by the resistance provided by the combined effects of the clamping contact of the functional surface clamping part, the clamping contact of the non-functional surface clamping part and the shape of the drawbead, the speed at which the drawn slab shrinks into the mold cavity is controlled. All three variables are possible and adjustment is very inconvenient. It may be that the gap of the non-functional clamping surface is too small, or that the drawbead is too high. If the mold fitter does not have enough debugging experience and cannot ensure that the gap of the clamping surface is uniform, the local pressure of the clamping surface will be too high and the drawn slab will not be able to flow. After the height of the drawbead is mistakenly lowered and the clamping surface is polished, it is found that the resistance provided is insufficient and the drawbead needs to be re-welded, which affects the life of the surface coating treatment.

[0006] Secondly, the drawing die and the drawing edge ring control the gap size to change the clamping force to provide friction resistance, thereby controlling the shrinkage speed and shrinkage of the drawn slab. The heat generated by friction will change the friction coefficient of the friction surface, causing the friction resistance to change with the extension of production time. In addition, the friction force will reduce the roughness of the mold surface and damage the mold surface, which will cause the product quality to be scratched or roughened, so that continuous and stable mass production cannot be achieved, and coating is needed to solve this problem. In short, the existing drawing die pressing structure consumes a lot of time and manpower and material resources for mold debugging, and the production stability is not high, which needs to be solved urgently. Summary of the invention

[0007] In view of this, one of the purposes of the present invention is to provide a drawn slab clamping structure, which breaks away from the design and improvement ideas of the existing drawing die pressing material structure, redefines the pressing material functional surface, and relies on the drawing ribs to provide the main slab flow resistance. The original functional surface clamping part and non-functional surface clamping part do not generate clamping force on the slab, but only play a guiding and limiting constraint role, so that the dimensional deviation redundancy of the mold clamping fitting surface is greatly improved, and the coating requirements of the clamping fitting surface are greatly reduced, which greatly reduces the difficulty and workload of mold debugging, and at the same time ensures the working life of the mold.

[0008] The technical solution is as follows:

[0009] A drawing plate blank clamping structure, comprising a drawing die and a drawing punch arranged oppositely, the drawing die is provided with a die cavity, the drawing die surface around the die cavity forms a pressure surface, the drawing die is provided with a pressing assembly, the pressing assembly comprises a drawing press, the drawing press is directly opposite to the pressure surface, the surface of the drawing press facing the pressure surface forms a top pressure surface, the top pressure surface and the pressure surface form a pressing fit surface group, the key is that the pressing fit surface group comprises an outer guide part, a drawing rib pressing part and an inner guide part connected in sequence from outside to inside;

[0010] The drawbead pressing part is a pair of arc surfaces facing each other, and the drawbead pressing part is used to press the slab to be processed and provide flow resistance for the slab;

[0011] The inner guide part and the outer guide part are both planar faces that match each other, and the surface clearance of the inner guide part is D 1 , the surface clearance of the outer guide portion is D 2 , the thickness of the slab is T, and:

[0012] T+0.05mm≤D 1 ≤T+0.1mm;

[0013] T+0.05mm≤D 2 ≤T+0.1mm.

[0014] As a preferred technical solution, the above-mentioned drawing rib pressing part includes a drawing convex rib arranged on the pressure-bearing surface, and a drawing concave rib opened on the top pressure surface and adapted to the drawing convex rib, and the two cooperate with each other;

[0015] The surface of the drawn convex rib is an arc surface, and the arc surface transitions with the pressure-bearing surfaces on both sides thereof with rounded corners.

[0016] As a preferred technical solution, the above-mentioned press fit surface group also includes a gap avoidance portion, which is located outside the outer guide portion, and the surface gap of the gap avoidance portion gradually decreases from the outside to the inside. The surface gap at any point of the gap avoidance portion is D 3 , D 3 The relationship with T is

[0017] T <D 3 ≤T+1mm.

[0018] As a preferred technical solution, the drawing presser on the outside of the above-mentioned compression fitting surface group and the surfaces opposite to the drawing die are spaced apart from each other to form a balance adjustment cavity, and a drawing balance adjustment block is sandwiched between the opposite surfaces of the balance adjustment cavity.

[0019] As a preferred technical solution, at least one drawing balance adjustment block gasket is further provided in the balance adjustment cavity, and the drawing balance adjustment block gasket and the drawing balance adjustment block are stacked between opposite surfaces of the balance adjustment cavity.

[0020] As a preferred technical solution, the above-mentioned pressing assembly also includes a machine tool push rod, and the front end of the machine tool push rod vertically presses the drawing presser so that the pressing surface presses the pressure-bearing surface.

[0021] The second object of the present invention is to provide a slab shrinkage control optimization method. The technical solution is as follows:

[0022] A slab shrinkage control optimization method includes the following steps:

[0023] S1, draw bead design: For the drawing die used to process the slab with a thickness of T, in the design stage, the stamping simulation software is used for simulation. The gap control is used in the simulation analysis. The surface gap between the inner guide and the outer guide is set to T+0.1mm. The size parameters of the draw bead are adjusted until the simulation analysis result shows that the slab does not crack and neck. The height H of the draw bead at this time is recorded. 0 , Radius R of the arc surface of the drawn rib 50 , and the inner and outer corner radius R 40 size;

[0024] S2, Processing of the drawing die pressing fit surface group: Based on the simulation data, in order to deal with the error between the real object and the simulation, the drawing rib height is H. 0 +1mm, inner and outer corner radius is R 40 -1mm is used as the processing parameter to maintain the radius R of the drawn rib corner 50 The width of the drawing rib remains unchanged, and the pressing fit surface group of the drawing die is processed by CNC;

[0025] S3, mold debugging: first polish the drawing die pressing mating surface group, then add 0.05 mm thick drawing balance adjustment block gaskets to all the drawing balance adjustment blocks in the drawing die balance adjustment cavity, that is, form the drawing die pressing structure as described above, use the blank to draw the trial production on the stamping machine, and inspect the trial product to observe whether there are cracks, necking, wrinkles, scratches, lack of material and other appearance defects;

[0026] S4, mold modification: if there is only a tensile defect, add a 0.05 mm drawing balance adjustment block gasket;

[0027] If there are only cracking or necking defects, enlarge the inner corner radius of the drawing rib corresponding to the cracking or necking area of ​​the trial product by 1mm, and then try again and observe the trial product. If the improvement is not obvious, enlarge the outer corner radius by 1mm, and finally reduce the height of the drawing rib by 0.5mm.

[0028] If only wrinkles occur, increase the pressure provided by the machine tool push rod, adjusting the amount by 50kN each time, and conduct trial production and observe the trial product until there is no wrinkle visible on the trial product.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: the dimensional deviation redundancy of the mold compression fitting surface is greatly improved, and the coating requirements of the compression fitting surface are greatly reduced, which greatly reduces the difficulty and workload of mold debugging, while ensuring the working life of the mold, thereby reducing the mold cost as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the drawing die structure of the control example;

[0031] Figure 2 for Figure 1 Enlarged view of the middle m part;

[0032] Figure 3 for Figure 2 The size of each area in the

[0033] Figure 4 It is a schematic diagram of the structure of the drawing die pressing material of the present invention;

[0034] Figure 5 The FLD diagram of cracking and wrinkling of a wheel cover inner panel stamping part was simulated and analyzed using the drawing die of the control example;

[0035] Figure 6 The coating requirement diagram of the blank face (pressure-bearing face) of a wheel cover inner panel stamping part using the drawing die of the control example for simulation analysis;

[0036] Figure 7 The FLD diagram of cracking and wrinkling of a wheel cover inner plate stamping part is simulated and analyzed by using the drawing die of the present invention;

[0037] Figure 8 A coating requirement diagram of the pressing surface (pressure-bearing surface) of a wheel cover inner plate stamping part subjected to a simulation analysis using the drawing die of the present invention;

[0038] Fig. 9 The product photo is of a wheel cover inner panel stamping part produced by using the drawing die of the present invention. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with embodiments and drawings.

[0040] Comparison Example

[0041] like Figure 1 and 2As shown, a drawing die comprises a drawing die 1 and a drawing punch 2 which are arranged opposite to each other, the drawing die 1 is provided with a die cavity 11, the die surface of the drawing die 1 around the die cavity 11 forms a pressure surface, the drawing die 1 is provided with a pressing assembly, the pressing assembly comprises a drawing press 3, the drawing press 3 is directly opposite to the pressure surface, the drawing press 3 forms a top pressure surface facing the surface of the pressure surface, and the top pressure surface forms a pressing fit surface group with the pressure surface. The pressing fit surface group comprises an air avoidance area 6, a non-functional surface pressing portion 7, a draw rib pressing portion 8 and a functional surface pressing portion 9 from outside to inside.

[0042] like Figure 3 , the surface gap d of the functional surface pressing part 9 1 The thickness T of the slab to be processed satisfies d 1 =T, surface gap d of non-functional surface pressing part 7 2 , the surface gap d of the avoidance area 6 3 , T≤d 2 ≤d 3 , the surface gap d of the avoidance area 6 3 Satisfy T≤d 3 ≤T+1mm.

[0043] The drawing bead pressing part 8 includes a drawing convex rib 12 arranged on the pressure bearing surface, and a drawing concave rib 31 opened on the top pressure surface and adapted to the drawing convex rib 12, and the two cooperate with each other. The height of the drawing convex rib 12 is denoted as h, and the surface of the drawing convex rib 12 is an arc surface, and the arc radius is denoted as R 5 The arc surface and the pressure-bearing surfaces on both sides have a rounded transition, and the radius of the inner and outer fillets formed are recorded as R 4 .

[0044] The surfaces of the drawing press 3 and the drawing die 1 on the outside of the press-fit surface group are spaced apart from each other to form a balance adjustment cavity, and a drawing balance adjustment block 4 is sandwiched between the opposite surfaces of the balance adjustment cavity. A drawing balance adjustment block gasket 5 can also be arranged in the balance adjustment cavity, and the drawing balance adjustment block gasket 5 and the drawing balance adjustment block 4 are stacked between the opposite surfaces of the balance adjustment cavity. The drawing balance adjustment block 4 and the drawing balance adjustment block gasket 5 are used to adjust the surface clearance of the press-fit surface group.

[0045] The pressing assembly also includes a machine tool push rod 32, which is arranged perpendicular to the parting line. The front end of the machine tool push rod 32 vertically presses the drawing press 3 so that the pressing surface presses the pressure-bearing surface, which is used to adjust the clamping force of the clamping fit surface group on the slab, thereby regulating the material flow resistance during drawing.

[0046] The friction force of the arc surface of the functional surface pressing part 9 and the drawing rib 12 on the slab is the main source of resistance to material flow.

[0047] The control example is an existing drawing die.

[0048] Embodiment 1

[0049] A drawn slab pressing structure, which is different from the control example in that Figure 4 As shown, the press-fit surface group includes an outer guide portion, a drawbead pressing portion, an inner guide portion and a gap-avoiding portion which are sequentially connected from the outside to the inside.

[0050] The inner guide part and the outer guide part are both planar faces that match each other. The outer guide part corresponds to the non-functional surface pressing part 7 in the control example, and the inner guide part corresponds to the functional surface pressing part 9. However, unlike the control example, the surface gap D of the inner guide part is 1 Surface clearance D with outer guide 2 They satisfy the following relationship with the plate blank thickness T:

[0051] T+0.05mm≤D 1 ≤T+0.1mm;

[0052] T+0.05mm≤D 2 ≤T+0.1mm.

[0053] The surface gap of the avoidance portion gradually decreases from the outside to the inside, and the surface gap d at any point of the avoidance portion 3 Still satisfied with T

[0054] T <D 3 ≤T+1mm.

[0055] The radius of the arc surface of the drawn rib 12' is denoted by R 5 ’ , 5mm≤R 5 ’ ≤7mm, the inner and outer fillet radii on both sides of the arc surface are recorded as R 4 ’ , 1mm≤R 5 ’ ≤3mm, the height of the drawn rib 12' is recorded as H, 0mm <H≤10mm。

[0056] The drawbead pressing part is a pair of arc surfaces facing each other, and the drawbead pressing part is used to press the slab to be processed and provide flow resistance for the slab.

[0057] The outer guide and the inner guide constrain the slab in a non-pressing manner, that is, the pressing force on the slab is close to zero. During the drawing process, the flow resistance of the outer guide to the slab is f 1, the flow resistance of the inner guide to the slab is f 2 The flow resistance of the drawbead pressing part to the slab is f 0 , f 0 With f 1 and f 2 satisfy

[0058] f 1 <f 0 ×5%;

[0059] f 1 <f 0 ×5%.

[0060] Since in the prior art (control example), the non-functional surface clamping part 7 and the functional surface clamping part 9 are very sensitive to the gap, a gap change of 0.01 mm will increase or decrease the flow resistance of the drawn sheet blank, and the difference between the stamping machine of the mold supplier and the stamping machine of the stamping factory cannot be less than plus or minus 0.05. The drawing rib 12' is used to provide the flow resistance of the drawn sheet blank, and the resistance is determined by the inner and outer fillets of the drawing rib 12' and the height of the drawing rib 12'. The effect of a change of 0.05 mm on the drawing rib 12' can be ignored. Once the height adjustment of the drawing rib 12' is completed, there is no need to worry about the influence of the difference between different stamping machines, and there is no need to control the gap within 0.05 mm. Generally, the area of ​​the die pressing surface accounts for 20% to 50% of the entire drawing die surface. The die surface gap adjustment needs to be performed twice on the stamping machine of the mold supplier and the stamping factory, thereby saving the mold fitter 20% to 50% of the die surface gap adjustment workload twice, reducing the mold manufacturing cost.

[0061] Compared with the control example, this embodiment breaks away from the design and improvement ideas of the existing drawing die pressing material structure, redefines the pressing material functional surface, relies on the drawing rib 12' to provide the main flow resistance of the slab, and the original functional surface pressing part and non-functional surface pressing part are designed as inner guide part and outer guide part, which do not generate pressing force on the slab, but only play a guiding and limiting constraint role, so that the dimensional deviation redundancy of the mold pressing fitting surface is greatly improved, which greatly reduces the difficulty and workload of mold debugging.

[0062] Embodiment 2

[0063] A method for optimizing shrinkage control of a drawn slab, comprising the following steps:

[0064] S1, draw bead design: For the drawing die used to process the slab with a thickness of T, in the design stage, use stamping simulation software (such as AUTOFORM R7) for simulation. Use gap control during simulation analysis. The surface gap between the functional surface clamping part 9 and the non-functional surface clamping part 7 is set to T+0.1mm. Adjust the size parameters of the draw bead until the simulation analysis result shows that the slab does not crack and neck. Record the height H of the draw rib 12' at this time.0 , Drawing rib 12' arc surface fillet radius R 50 , and the inner and outer corner radius R 40 size;

[0065] S2, processing of the drawing die pressing fit surface group: Based on the simulation data, in order to deal with the error between the real object and the simulation, the height of the drawing rib 12' is H 0 +1mm, inner and outer corner radius is R 40 -1mm is the processing parameter, and the radius of the drawn rib is 12'. 50 The width of the drawing rib 12' remains unchanged, and the drawing die pressing fit surface group is subjected to CNC machining;

[0066] S3, mold debugging: first polish the pressing and fitting surface group of the drawing die, then add 0.05 mm thick drawing balance adjustment block gaskets 5 to all the drawing balance adjustment blocks 4 in the drawing die balance adjustment cavity, use the blank to draw the trial production on the stamping machine, and check the trial production products to observe whether there are cracks, necking, wrinkles, scratches (hair), missing materials and other appearance defects;

[0067] S4, mold modification: if there is only a tensile (hair) defect, add a 0.05 mm drawing balance adjustment block gasket 5;

[0068] If there is only a crack or necking defect, enlarge the inner corner radius of the drawing rib 12 corresponding to the crack or necking area of ​​the trial product by 1mm, and then try again and observe the trial product. If the improvement is not obvious, enlarge the outer corner radius by 1mm, and finally reduce the height of the drawing rib 12 by 0.5mm.

[0069] If only wrinkles occur, increase the pressure provided by the machine tool push rod, adjusting the amount by 50kN each time, and conduct trial production and observe the trial product until there is no wrinkle visible on the trial product.

[0070] The final modified mold is the mold having the drawn slab clamping structure described in Example 1.

[0071] Taking the drawing forming of a wheel cover inner panel of a vehicle model as an example, the optimization process of blank shrinkage control is specifically described. The blank material grade DC04 and the thickness of the wheel cover inner panel are 0.65mm.

[0072] The drawing die of the existing control example is used. Pressure control is used in the simulation analysis. The gap between the functional surface pressing part 9 and the non-functional surface pressing part 7 is set to the material thickness of 0.65 mm. The drawing rib is adjusted to the size parameter of the non-cracking neck according to the analysis results. The height H of the drawing rib 12 is 0 =4mm. Forming limit diagram (cracking and wrinkling FLD diagram) is as follows Figure 5As shown in Figure 2, the simulation analysis results show that the inner fillet of the drawing rib and the 9 positions of the functional surface pressing part need to be coated. Figure 6 shown.

[0073] The material pressing structure of the first embodiment is adopted. The gap control is used in the simulation analysis, and the surface gap D of the inner guide part is 1 Surface clearance D with outer guide 2 The material thickness is set to 0.65mm, and the drawing rib 12' is adjusted to the size parameter of no cracking and necking according to the analysis results: H = 7mm. Figure 7 As shown in FIG. 1 , the simulation analysis results show that coating treatment is only required at the inner fillet of the drawn rib 12 ′, such as Figure 8 As shown, however, since the wear of the R corner and the reduction of the fillet radius of the drawing rib 12' by 0.1-0.5 mm will not have a significant impact on the resistance generated by the drawing rib 12', there is no need for surface coating treatment.

[0074] By comparison Figure 5 and Figure 7 , using the drawing die of the existing control example and the drawing die of Example 1, both schemes can simulate qualified results, but in the actual mold debugging, the drawing rib parameters calculated by the stamping simulation software are different from the actual ones. This is because the clearance of the pressing fit surface during simulation is uniform and consistent in the ideal state, but the actual mold CNC machining and mold fitter mold repair cannot meet the requirements. The scheme of Example 1 is different. After the drawing rib parameters are obtained by the stamping simulation software, since the pressing surfaces of the outer guide part and the inner guide part do not need to be in a fitting state, the CNC machining accuracy and mold fitter can be well met by using the drawing balance adjustment block gasket 5. The flow resistance of the slab is completely provided by the drawing rib, so the drawing rib parameters obtained by the stamping simulation software can be consistent with the actual ones, which also proves that the improved scheme is effective.

[0075] The wheel cover inner panel has completed the development and debugging of the drawing die through the improved method, such as Fig. 9 The drawn products have no appearance defects and meet the needs of mass production.

[0076] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Under the guidance of the present invention, ordinary technicians in this field can make various similar expressions without violating the purpose and claims of the present invention, and such changes all fall within the scope of protection of the present invention.

Claims

1. A slab shrinkage control optimization method, which adopts a drawn slab clamping structure, the drawn slab clamping structure comprises a drawing die (1) and a drawing punch (2) arranged relatively to each other, the drawing die (1) is provided with a die cavity (11), the die surface of the drawing die (1) around the die cavity (11) forms a pressure surface, the drawing die (1) is provided with a pressing assembly, the pressing assembly comprises a drawing press (3), the drawing press (3) is directly opposite to the pressure surface, the surface of the drawing press (3) facing the pressure surface forms a top pressure surface, the top pressure surface and the pressure surface form a pressing fit surface group, characterized in that: The press-fit surface group comprises an outer guide portion, a drawbead pressing portion and an inner guide portion which are sequentially connected from outside to inside; The drawbead pressing part is a pair of arc surfaces facing each other, and the drawbead pressing part is used to press the slab to be processed and provide flow resistance for the slab; The inner guide part and the outer guide part are both planar faces that match each other, the surface gap of the inner guide part is D1, the surface gap of the outer guide part is D2, the thickness of the slab is T, and: T+0.05mm≤D1≤T+0.1mm; T+0.05mm≤D2≤T+0.1mm; The drawing rib pressing portion comprises a drawing convex rib (12') arranged on the pressure-bearing surface, and a drawing concave rib (31') opened on the top pressure surface and adapted to the drawing convex rib (12'), the two cooperating with each other; The surface of the drawn convex rib (12') is an arc surface, and the arc surface has a rounded transition with the pressure-bearing surfaces on both sides thereof; The press-fit surface group further includes a clearance portion, which is located outside the outer guide portion. The surface clearance of the clearance portion gradually decreases from the outside to the inside. The surface clearance at any point of the clearance portion is D3, and the relationship between D3 and T is: T< D3≤T+1mm; The surfaces of the drawing press (3) and the drawing die (1) on the outside of the press-fit surface group are spaced apart from each other to form a balance adjustment cavity, and a drawing balance adjustment block (4) is sandwiched between the opposite surfaces of the balance adjustment cavity; At least one drawing balance adjustment block gasket (5) is also provided in the balance adjustment cavity, and the drawing balance adjustment block gasket (5) and the drawing balance adjustment block (4) are stacked between opposite surfaces of the balance adjustment cavity; The material pressing assembly further comprises a machine tool push rod (32), the front end of which vertically presses the drawing press (3) so that the pressing surface presses the pressure bearing surface; It is characterized by comprising the following steps: S1, draw bead design: For the drawing die used to process the slab with a thickness of T, in the design stage, the stamping simulation software is used for simulation. The gap control is used in the simulation analysis. The surface gap between the inner guide and the outer guide is set to T+0.1mm. The size parameters of the draw bead are adjusted until the simulation analysis result shows that the slab does not crack and shrink. The height H0 of the drawing rib (12') and the radius R of the arc surface of the drawing rib (12') are recorded. 50 , and the inner and outer corner radius R 40 size; S2, processing of the drawing die pressing fit surface group: Based on the simulation data, in order to deal with the error between the real object and the simulation, the height of the drawing rib (12') is H0+1mm, the radius of the inner and outer corners is R 40 -1mm as processing parameter, keep the radius R of the drawn rib (12') 50 The width of the drawing rib (12') remains unchanged, and the drawing die pressing fit surface group is subjected to CNC machining; S3, mold debugging: first polish the pressing and fitting surface group of the drawing die, then add 0.05 mm thick drawing balance adjustment block gaskets (5) to all the drawing balance adjustment blocks (4) in the drawing die balance adjustment cavity, so as to form the drawing slab pressing structure, use the slab to draw the trial production on the stamping machine, and inspect the trial product to observe whether there is cracking, necking, wrinkling, tearing, or material shortage; S4, mold modification: if there is only a tensile defect, add a 0.05 mm tensile balance adjustment block gasket (5); If there is only a crack or necking defect, enlarge the inner corner radius of the drawing rib (12') corresponding to the crack or necking area of ​​the trial product by 1mm, and then re-produce and observe the trial product. If there is no obvious improvement, enlarge the outer corner radius by 1mm, and finally reduce the height of the drawing rib (12') by 0.5mm. If only wrinkles occur, increase the pressure provided by the machine tool push rod, adjusting the amount by 50kN each time, and conduct trial production and observe the trial product until there is no wrinkle visible on the trial product.

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