A stamped part and a method of forming the same

Abstract

The application discloses a stamping part and a forming method thereof. The stamping part comprises a stamping body. The stamping body is in a plate structure and has a stamping groove. The stamping groove has a large opening arranged at one end of the stamping body and a small opening arranged at the other end of the stamping body. The large opening and the small opening are located at the same side of the stamping body, and the opening direction of the large opening cooperates with the opening direction of the small opening to form an included angle A. The included angle A is not less than 5° and not more than 10°. Along the stamping direction of the stamping part, a distance H is formed between the upper end of the large opening and the upper end of the small opening, and the distance H is not more than 30 mm. When 5°≤A≤10° and H≤30 mm are satisfied at the same time, the stamping part realizes the coordinated control of "low height difference + small included angle" in the same mold closing process. The stamping material is synchronously and uniformly drawn into the mold cavity along the directions of the two openings, and the forming defects are completely eliminated, thereby providing a stable geometric and wall thickness basis for subsequent flanging and welding processes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stamping forming, and more particularly to a stamping part and a forming method thereof. BACKGROUND

[0002] In the field of stamping forming, when a conical part needs to retain two openings of different sizes on a main body at the same time, the existing process usually arranges the two openings too close or too far apart, and the directions of the two openings are almost parallel or have too large an angle. From the perspective of stamping process, this arrangement brings two conflicting material flows: one flows to the large opening, and the other flows to the small opening. When the opening directions are too parallel, the metal in the flange area is strongly compressed in the circumferential direction, which is prone to wrinkling near the die port; if the angle is too large, the metal will be excessively elongated on the small opening side, resulting in local cracking. At the same time, the greater the height difference between the openings, the longer the material travels from the flange to the farthest port, and the metal at the small opening is insufficiently supplied, further exacerbating thinning or even cracking. Conversely, too small a difference will cause the metal on the large opening side to accumulate, also causing wrinkling. The existing technology has not found a geometric relationship that can balance the two flows at the same time and form once in a single die set, resulting in the coexistence of cracks and wrinkles, making it difficult to improve the yield. SUMMARY

[0003] In order to overcome the above-mentioned defects of the prior art, the present application provides a stamping part and a forming method thereof to solve at least part of the technical problems raised in the background art.

[0004] To achieve the above-mentioned purpose, the first aspect of the present application provides a stamping part, which comprises: a stamping body, the stamping body being a plate structure and having a stamping groove; the stamping groove has a large opening arranged at one end of the stamping body and a small opening arranged at the other end of the stamping body; the large opening and the small opening are both located on the same side of the stamping body, and the opening direction of the large opening cooperates with the opening direction of the small opening to form an included angle A; the included angle A is not less than 5° and not more than 10°; wherein, along the stamping direction of the stamping part, the distance H between the upper end of the large opening and the upper end of the small opening is not more than 30 mm.

[0005] The specific technical effect of the embodiment is that when the included angle A is strictly controlled within 5°-10°, a sufficient but not excessive "V-shaped" diversion angle is formed between the axes of the large and small openings. The angle ensures that the radial tensile stress is always maintained at 220-250 MPa, prevents circumferential compression wrinkling, and avoids material retention caused by traditional parallel openings, thereby reducing the probability of local compression wrinkling. Limiting the vertical distance H to within 30 mm compresses the material flow path difference between the two opening vertices, thereby ensuring that the feeding speeds on both sides are close to uniform, avoiding excessive thinning on one side, and ensuring that the mold stroke is short and the forming cycle is shortened by more than 15%. When 5°≤A≤10° and H≤30 mm are met at the same time, the stamping part realizes "low height difference + small included angle" coordinated control in the same clamping process; the stamping material is synchronously and uniformly drawn into the mold cavity along the two opening directions, and the maximum thinning rate is locked at ≤25%; forming defects (cracks, wrinkles) are completely eliminated, providing a stable geometric and wall thickness basis for subsequent flanging and welding processes.

[0006] Optionally, the shape of the large opening and the shape of the small opening are both semicircular, and the radius of the large opening is R and the radius of the small opening is r; wherein the difference between R and r is not more than 30 mm.

[0007] The specific technical effect of the embodiment is that the large and small openings are both semicircular, and the difference between the large opening radius R and the small opening radius r is ≤30 mm; when R-r exceeds 30 mm, the required material supplement amount of the two ports differs too much, which easily leads to thinning >35% at the small port; this limitation makes the required material flow of the two ports in the same order of magnitude, and the pressure fluctuation range can be compressed to ±3%, achieving a wall thickness difference <0.05 mm between the two pieces when one mold produces two pieces.

[0008] Optionally, the stamping part further comprises a pressure plate; the pressure plate is arranged around the stamping body, and along the stamping direction of the stamping part, the pressure plate is located at the lower end of the stamping body; wherein the width of the pressure plate is 15-20 mm, and along the direction from inside to outside of the pressure plate, the pressure plate is inclined upward by 1-3°.

[0009] The specific technical effect of the embodiment is that the pressure plate width of 15-20 mm and the 1-3° inclined angle form a conical pressure surface: the ring width of 15-20 mm ensures sufficient pressure area, and the pressure of 18-22 MPa prevents flange wrinkling; the 1-3° inclined angle provides pre-direction for the material entering the two-stage deep drawing rib, and reduces the rib top wear by 25%.

[0010] Optionally, the blank holder further comprises outer stretchers and inner stretchers; the outer stretchers and the inner stretchers are arranged around the stamping body, and the distance between the outer stretchers and the inner stretchers is 8-10 mm; the height of the outer stretchers is 1-1.2 mm, and the radius of the top round corner of the outer stretchers is 0.7-0.9 mm; the height of the inner stretchers is 0.5-0.7 mm, and the radius of the top round corner of the inner stretchers is 0.9-1 mm.

[0011] The specific technical effect of the embodiment is that the outer stretchers of the double-stage stretchers have a height of 1-1.2 mm, the top of the stretchers has a radius of 0.7-0.9 mm, the inner stretchers have a height of 0.5-0.7 mm, and the top of the stretchers has a radius of 0.9-1 mm, forming a "high-low-wide" gradient; the outer stretchers generate a local resistance of 260-280 MPa to establish a main tensile stress; the inner stretchers are secondarily homogenized to prevent local stress peaks; and the distance between the stretchers is 8-10 mm to ensure that a stable pressure buffer zone is formed between the stretchers to avoid cracks between the stretchers.

[0012] Optionally, along the extension direction of the stamping body from the large opening to the small opening, the stamping body comprises, in sequence, a corner material suction area, a first straight wall area, a corner material supplement area, and a second straight wall area; the corner of the corner material suction area is smaller than the corner of the corner material supplement area, and the first straight wall area and the second straight wall area are both conical cylinder structures.

[0013] The specific technical effect of the embodiment is that the stamping body comprises, in sequence along the extension direction, a corner material suction area, a first straight wall area, a corner material supplement area, and a second straight wall area; the design that the corner of the corner material suction area is smaller than the corner of the corner material supplement area preferentially guides the excess material at the large port into the material suction groove, and the small port is secondarily supplemented through the material supplement area, so that the material balance of "suction first and then supplement" is achieved; both the first straight wall area and the second straight wall area are conical cylinder structures, the draft angle is 0.5-1°, the demolding force is reduced by 15%, and 0.8 mm of uniform allowance is reserved for subsequent flanging.

[0014] Optionally, the radius of the inlet round corner of the corner material suction area is 2.5-3.5 mm, and the radius of the outlet round corner of the corner material suction area is 5-7 mm.

[0015] The specific technical effect of the embodiment is that the inlet round corner R2.5-3.5 mm and the outlet round corner R5-7 mm of the corner material suction area form a "slow-in and fast-out" streamline: the large inlet round corner reduces the initial bending strain by 20%; and the large outlet round corner prevents reverse bending cracks, so that the thinning rate at this position is stably maintained at 20-22%.

[0016] The second aspect of the application provides a forming method of a stamping part, which is used to manufacture the stamping part as described above.

[0017] Optionally, the forming method comprises: step one, stamping the plate material to form two stamping pieces through a stamping device, the two stamping pieces are symmetrically arranged and connected through a connecting part.

[0018] Step two, cutting the connecting part and the two stamping pieces through a cutting device, so as to obtain the two stamping pieces.

[0019] Step three, polishing the cutting areas of the two stamping pieces respectively.

[0020] The specific technical effect of the embodiment is that the two stamping pieces share a connecting part, the number of mold cavities is halved, and the mold cost is reduced.

[0021] Optionally, in step one, the two ends of the connecting part are connected with the large openings of the two stamping pieces respectively, and the distance between the large openings of the two stamping pieces is smaller than the distance between the small openings of the two stamping pieces.

[0022] The specific technical effect of the embodiment is that the two ends of the connecting part are connected with the large openings, and the distance between the two large openings is smaller than the distance between the two small openings; during mold closing, the material in the large opening area is compressed first, and then flows to the small opening area, naturally forming a gradient feeding from large to small, and extra drawbead adjustment is saved.

[0023] Optionally, the connecting part is in the form of an elbow pipe.

[0024] The specific technical effect of the embodiment is that the elbow pipe configuration acts as an elastic buffer section during mold closing, absorbs the pressure fluctuation, and reduces the instantaneous load peak value of the pressure ring; after cutting, the elbow pipe naturally separates without secondary deformation, and the shaping process required by the traditional straight connection is saved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A structure diagram of a stamping piece of the present application Figure One .

[0026] Figure 2 A structure diagram of a stamping piece of the present application Figure Two .

[0027] Figure 3 A schematic diagram of a stamping piece of the present application during stamping Figure One .

[0028] Figure 4 A schematic diagram of a stamping piece of the present application during stamping Figure Two .

[0029] The reference signs are: 1, large opening; 2, small opening; 3, pressure plate; 4, corner suction area; 5, first straight wall area; 6, corner supplement area; 7, second straight wall area; 8, connecting part. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0031] As shown in Figure 1 and Figure 2 , a stamping part includes a stamping body and a pressure plate 3.

[0032] The stamping body is a plate structure and has a stamping groove; the stamping groove has a large opening 1 arranged at one end of the stamping body and a small opening 2 arranged at the other end of the stamping body; the large opening 1 and the small opening 2 are both located on the same side of the stamping body, and the opening direction of the large opening 1 cooperates with the opening direction of the small opening 2 to form an included angle A; the included angle A is not less than 5° and not more than 10°; wherein, along the stamping direction of the stamping part, a distance H is formed between the upper end of the large opening 1 and the upper end of the small opening 2, and the distance H is not more than 30 mm.

[0033] It should be noted that the large opening 1 in the present embodiment refers to a larger opening cross-sectional area, and the small opening 2 refers to a smaller opening cross-sectional area, that is, the cross-sectional area of the large opening 1 in the present embodiment is larger than that of the small opening 2.

[0034] The included angle A in the present embodiment can be 5°, 6°, 7°, 8°, 9°, 10°, or any degree between 5° and 10°, and the present disclosure does not limit this.

[0035] When the included angle A is strictly controlled within 5°-10°, a sufficient but not excessive "V-shaped" angle of diversion is formed between the axes of the large opening 1 and the small opening 2. This angle ensures that the radial tensile stress is always maintained at 220-250 MPa, preventing circumferential compression wrinkles; and avoiding material stagnation caused by traditional parallel pipe openings, reducing the probability of local compression wrinkles. Limiting the vertical distance of the distance H to within 30 mm compresses the material flow path difference between the two opening vertices, thereby ensuring that the feeding speeds on both sides are close to uniform, avoiding excessive thinning on one side; and ensuring that the mold stroke is short, and the forming cycle is shortened by more than 15%. When 5°≤A≤10° and H≤30 mm are met at the same time, the stamping part realizes "low height difference + small included angle" collaborative control in the same clamping process; the stamping material is synchronously and uniformly drawn into the mold cavity along the direction of the two openings, and the maximum thinning rate is locked at ≤25%; forming defects (cracks, wrinkles) are completely eliminated, providing a stable geometric and wall thickness basis for subsequent flanging and welding processes.

[0036] As an optional implementation, the shapes of the large opening 1 and the small opening 2 are both semicircular, and the radius of the large opening 1 is R and the radius of the small opening 2 is r; wherein the difference between R and r is not more than 30 mm. Both the large opening 1 and the small opening 2 are semicircular, and the difference between the radius R of the large opening 1 and the radius r of the small opening 2 is ≤30 mm; when R-r exceeds 30 mm, the required material supplement amount of the two ports is too different, which easily leads to thinning >35% at the small port; the present limitation makes the required material flow of the two ports in the same order of magnitude, and the pressure fluctuation range can be compressed to ±3%, realizing that the wall thickness difference of the two pieces is <0.05 mm when one mold double pieces.

[0037] As an optional implementation, the blank holder plate 3 is arranged around the stamping body, and along the stamping direction of the stamping part, the blank holder plate 3 is located at the lower end of the stamping body. Wherein, the width of the blank holder plate 3 is 15-20 mm, and along the direction from inside to outside of the blank holder plate 3, the blank holder plate 3 is inclined upward by 1-3°. The 15-20 mm width of the blank holder plate 3 and the 1-3° inclined angle form a conical blank holder surface: the ring width of 15-20 mm ensures sufficient blank holding area, and the pressure is 18-22 MPa, preventing flange wrinkles; the 1-3° inclined angle provides pre-direction for the material entering the two-stage deep drawing rib, reducing the rib top wear by 25%.

[0038] As an optional implementation, the blank holder 3 is further provided with outer and inner stretchers; the outer and inner stretchers are arranged around the stamping body, and the distance between the outer and inner stretchers is 8-10 mm; the height of the outer stretcher is 1-1.2 mm, and the radius of the top corner of the outer stretcher is 0.7-0.9 mm; the height of the inner stretcher is 0.5-0.7 mm, and the radius of the top corner of the inner stretcher is 0.9-1 mm. The outer stretcher of the two-stage deep drawing stretcher has a height of 1-1.2 mm, and the top of the outer stretcher has a radius of 0.7-0.9 mm; the inner stretcher has a height of 0.5-0.7 mm, and the top of the inner stretcher has a radius of 0.9-1 mm, forming a “high-low-wide” gradient; wherein the outer stretcher generates a local resistance of 260-280 MPa to establish a main tensile stress; the inner stretcher is secondary homogenized to prevent local stress peaks; and the distance between the stretchers is 8-10 mm to ensure that a stable pressure buffer zone is formed between the two stretchers to avoid cracks between the stretchers.

[0039] As an optional implementation, along the extension direction of the stamping body extending from the large opening 1 to the small opening 2, the stamping body sequentially includes a corner material suction area 4, a first straight wall area 5, a corner material supplement area 6, and a second straight wall area 7; wherein the corner of the corner material suction area 4 is smaller than the corner of the corner material supplement area 6, and the first straight wall area 5 and the second straight wall area 7 are both conical cylinder structures. The stamping body sequentially includes the corner material suction area 4, the first straight wall area 5, the corner material supplement area 6, and the second straight wall area 7 along the extension direction; the design that the corner of the corner material suction area 4 is smaller than the corner of the corner material supplement area 6 preferentially guides the excess material of the large port into the material suction groove, and the small port is supplemented again through the material supplement area, so as to realize the material balance of “suction first and then supplement”; both of the straight wall areas adopt the conical cylinder structure, the draft angle is 0.5-1°, the demolding force is reduced by 15%, and 0.8 mm uniform allowance is reserved for subsequent flanging.

[0040] As an optional implementation, the radius of the inlet corner of the corner material suction area 4 is 2.5-3.5 mm, and the radius of the outlet corner of the corner material suction area 4 is 5-7 mm. The inlet corner radius 2.5-3.5 mm and the outlet corner radius 5-7 mm of the corner material suction area 4 form a “slow-in and fast-out” streamline: the large inlet corner reduces the initial bending strain by 20%; and the large outlet corner prevents reverse bending cracks, so that the thinning rate at this position is stably controlled within 20-22%.

[0041] As shown in Figure 3 and Figure 4 , the second aspect of the present application provides a forming method of a stamping part, and the forming method is used to manufacture the stamping part as above.

[0042] As an optional embodiment, the forming method comprises: step 0 - plate pretreatment: select a steel plate coil with an aluminum-silicon plated surface, after leveling, cleaning and on-line oiling, send it to the blanking station. After leveling, the plate waviness is <1 mm / m, the surface cleanliness is Sa 2.5 level, which ensures that the friction coefficient is stable at 0.10-0.12 during subsequent deep drawing, and reduces mold contamination.

[0043] Step 1 - blanking and pre-punching positioning hole: a ϕ200 mm disc is punched out by the first station of the die, and a ϕ4 mm positioning hole is pre-punched at both ends of the disc symmetry axis. The height of the blanking burr is <0.05 mm; the positioning hole makes the blank radial jump <0.1 mm in the mold during subsequent deep drawing, ensuring the symmetry of the two pieces.

[0044] Step 2 - mold deep drawing (synchronous forming of two pieces): 2.1 feeding: the manipulator sends the blanking disc into the deep drawing die, and the positioning pin is inserted into the pre-punched hole.

[0045] 2.2 pressing: the pressing plate 3 presses the flange ring with an initial force of 18 kN, and then the closed-loop hydraulic system adjusts the blank holder force in real time to 20 ± 0.4 kN according to the feedback of the four-point pressure sensor.

[0046] 2.3 deep drawing: the punch goes down 120 mm at an average speed of 100 mm / s, and stays at the end of the stroke for 0.3 s for pressure holding and shaping to obtain two symmetrically arranged stampings as shown in Figure 3 and Figure 4 , wherein the two stampings are connected by a connecting portion 8, Figure 3 is a top view of the two stampings, showing the outer convex outer surface of the two stampings and the connecting portion 8; Figure 4 is a bottom view of the two stampings, showing the inner concave inner surface of the two stampings and the connecting portion 8.

[0047] Such an arrangement can make the maximum thinning rate of the two stampings 23%, and the wall thickness difference between the two pieces ≤0.03 mm; pressure holding and shaping makes the flange flatness ≤0.15 mm, directly meeting the laser welding clamp; the cycle is 15 s / two pieces, which is 40% shorter than the traditional two-die scheme.

[0048] Step 3 - online detection and mold protection: the mold is integrated with an eddy current thickness gauge and an infrared temperature probe to provide real-time feedback of the wall thickness curve and the mold temperature; if the thinning in any area is found to be >25%, the system will automatically shut down and alarm. 100% online detection is achieved, the first piece qualification rate is improved from 15% to 95%, mold early wear is warned, and unexpected downtime is reduced.

[0049] Step 4 - connection 8 elbow forming: in the last 3 mm of the drawing stroke, the connection 8 is pressed into an R50 mm elbow by the in-mold movable wedge. The elbow absorbs the 18% pressure fluctuation when the mold is closed, reducing the instantaneous load peak of the pressure ring; the elbow springback is <0.1 mm, and no trimming is required after cutting.

[0050] Step 5 - laser cutting separation: after forming, the whole piece is moved to the fiber laser cutting station by the robot, and is cut along the center line of the elbow at a power of 3 kW and a spot of 0.15 mm. Nitrogen protection is provided during cutting, and the gas pressure is 0.8 MPa. The cutting seam width is 0.15 mm, the heat affected zone is <0.1 mm, and no secondary burr is generated after cutting; the cutting time is 3 s / piece, which is reduced by 50% compared with mechanical punching; the elbow naturally separates, and the center distance of the two pieces is maintained within ±0.05 mm.

[0051] Step 6 - polishing of the cut end face: after cutting, the individual punched part enters the sand belt polishing station, and the 400# sand belt is wet polished at a speed of 1200 rpm and a pressure of 0.2 MPa, with a cooling liquid flow of 2 L / min. The end face roughness Ra is ≤0.4 µm, and the laser welding penetration fluctuation CV is <3%; the polishing time is 2 s / piece, there is no dust, and it meets the clean production requirements.

[0052] As an optional embodiment, in step one, the two ends of the connection 8 are connected to the large openings 1 of the two punched parts, and the distance between the two large openings 1 is less than the distance between the two small openings 2. The two ends of the connection 8 are connected to the large openings 1, and the distance between the two large openings 1 is less than the distance between the two small openings 2; during mold closing, the material in the large opening 1 area is compressed first, and then flows to the small opening 2, naturally forming a "large to small" gradient material supply, and eliminating the need for additional drawbead adjustment.

[0053] As an optional embodiment, the connection 8 is in the form of an elbow. The elbow configuration acts as an "elastic buffer section" during mold closing, absorbing the pressure fluctuation and reducing the instantaneous load peak of the pressure ring; after cutting, the elbow naturally separates without secondary deformation, eliminating the need for the traditional straight connection trimming process.

[0054] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A stamped part, characterized by: The stamping piece comprises a stamping body which is in a plate structure and has a stamping groove; the stamping groove has a large opening arranged at one end of the stamping body and a small opening arranged at the other end of the stamping body; the large opening and the small opening are both located at the same side of the stamping body, and the opening direction of the large opening and the opening direction of the small opening form an included angle A; the included angle A is not less than 5° and not more than 10°; wherein, along the stamping direction of the stamping piece, a distance H is formed between the upper end of the large opening and the upper end of the small opening, and the distance H is not more than 30 mm.

2. A stamped part according to claim 1, characterized in that: The shapes of the large opening and the small opening are both semicircular, and the radius of the large opening is R and the radius of the small opening is r; wherein, the difference between R and r is not more than 30 mm.

3. A stamped part according to claim 2, characterized in that: The stamping piece further comprises a pressing plate; the pressing plate is arranged around the stamping body, and along the stamping direction of the stamping piece, the pressing plate is located at the lower end of the stamping body; wherein, the width of the pressing plate is 15-20 mm, and along the direction from inside to outside of the pressing plate, the pressing plate is inclined upward by 1-3°.

4. A stamped part according to claim 3, characterized in that: The pressing plate is further provided with an outer stretching rib and an inner stretching rib; the outer stretching rib and the inner stretching rib both surround the stamping body, and the distance between the outer stretching rib and the inner stretching rib is 8-10 mm; the height of the outer stretching rib is 1-1.2 mm, and the radius of the top round corner of the outer stretching rib is 0.7-0.9 mm; the height of the inner stretching rib is 0.5-0.7 mm, and the radius of the top round corner of the inner stretching rib is 0.9-1 mm.

5. A stamped part according to claim 2, characterized in that: Along the extension direction of the stamping body extending from the large opening to the small opening, the stamping body comprises, in sequence, a corner material suction area, a first straight wall area, a corner material supplement area and a second straight wall area; wherein, the corner of the corner material suction area is smaller than the corner of the corner material supplement area, and the first straight wall area and the second straight wall area are both in a conical cylinder structure.

6. A stamped part according to claim 5, characterized in that: The radius of the inlet round corner of the corner material suction area is 2.5-3.5 mm, and the radius of the outlet round corner of the corner material suction area is 5-7 mm.

7. A method of forming a stamped part, characterized by: The forming method is used for manufacturing the stamping piece according to any one of claims 1-6.

8. A method of forming a stamped part according to claim 7, wherein: The forming method comprises: step one, stamping a plate by a stamping device to form two stamping pieces, the two stamping pieces are symmetrically arranged and connected by a connecting part; step two, cutting the connecting part and the two stamping pieces by a cutting device to obtain two stamping pieces; step three, polishing the cutting areas of the two stamping pieces respectively.

9. A method of forming a stamped part according to claim 8, wherein: In step one, the two ends of the connecting part are respectively connected with the large openings of the two stamping pieces, and the distance between the large openings of the two stamping pieces is smaller than the distance between the small openings of the two stamping pieces.

10. A method of forming a stamped part according to claim 8, wherein: The connecting part is in the form of an elbow pipe.

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