Deep drawing die suitable for small-diameter and thin-wall ellipsoid and forming method

Abstract

The invention discloses a deep drawing die suitable for a small-diameter and thin-wall ellipsoid and a forming method. The deep drawing die comprises an upper die assembly, a lower die assembly and an ejection mechanism. The lower die assembly comprises a lower die plate fixed to the upper surface of a lower platform of the hydraulic machine, an inverted-T-shaped male die corresponding to the female die is fixedly connected to the upper surface of the lower die plate, stroke limiting columns are arranged on the two sides of the inverted-T-shaped lower portion of the male die respectively, the inverted-T-shaped upper portion of the male die is sleeved with a floating blank holder, and the stroke limiting columns are located below the floating blank holder. The ejection mechanism comprises a hydraulic cushion ejection plate located at the bottom end of the hydraulic machine lower platform, and movable ejection rods are arranged on the left side and the right side in the hydraulic cushion ejection plate correspondingly. The movable ejector rod sequentially penetrates through the hydraulic machine lower platform and the lower die plate from the interior of the hydraulic cushion ejector plate till penetrating through the two sides of the inverted-T-shaped lower portion of the male die and extending to the position below the floating blank holder. The production cycle is shortened, and the obtained ellipsoid inner molded surface is high in size precision, stable in quality and excellent in consistency.

Description

Technical Field

[0001] This invention belongs to the field of metal deep drawing technology, specifically referring to a deep drawing die and forming method suitable for small-diameter, thin-walled ellipsoids. Background Technology

[0002] In the field of solid rocket motor manufacturing, ultra-high strength steel is currently the dominant material in my country's engine casing manufacturing. Ultra-high strength steel has advantages such as good elongation and reduction of area in the annealed state, as well as good plastic processing performance, and can be used for cold plastic forming.

[0003] However, deep drawing of ultra-high strength thin-walled ellipsoids has always been a technical challenge in forming. In actual production, there are two processing schemes for ultra-high strength thin-walled ellipsoids.

[0004] One approach is to use cold-rolled steel sheets for one-time deep drawing, but the deep drawing process often results in problems such as local bulging, wrinkling, and excessive thinning of the transition zone between the column segment and the ellipsoid. Another option is to use a forging machine to process thin-walled ellipsoids, but this has the problems of high cost and a single-piece processing cycle of more than 7 days, which cannot meet the schedule requirements of mass production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a deep-drawing die and forming method suitable for small-diameter, thin-walled ellipsoids. It can cold-form thin-walled ellipsoids in one step, ensuring that each ellipsoid has stable and consistent quality, avoiding problems such as local bulging and wrinkling. This not only reduces production costs but also enables batch and efficient processing and shortens the production cycle.

[0006] To achieve the above objectives, this invention designs a deep drawing die suitable for small-diameter, thin-walled ellipsoids, used for forming thin-walled ellipsoidal parts for engine combustion chamber housings. Its special feature is that it includes an upper die assembly, a lower die assembly, and an ejection mechanism. The upper mold assembly includes an upper mold plate that is fastened to the upper slide of the hydraulic press, and a downward-opening concave mold is fastened to the lower end of the upper mold plate; The lower mold assembly includes a lower template fixed on the upper surface of the lower platform of the hydraulic press. A type 1 punch corresponding to the concave mold is fixedly connected to the upper surface of the lower template. Stroke limiting posts are respectively provided on both sides of the lower part of the type 1 punch. A floating pressure ring is sleeved on the upper part of the type 1 punch, and the stroke limiting posts are located below the floating pressure ring. The ellipsoidal component is placed between the die and the punch, and the edge of the ellipsoidal component is pressed between the floating pressure ring and the die pressing surface. The ejection mechanism includes a hydraulic pad top plate located at the bottom of the lower platform of the hydraulic press. Movable ejector rods are respectively provided on the left and right sides inside the hydraulic pad top plate. The movable ejector rods extend from inside the hydraulic pad top plate, through the lower platform of the hydraulic press and the lower template, until they penetrate the lower sides of the upper part of the punch and extend to the bottom of the floating pressure ring. The top of the movable top rod is equipped with a dedicated adjustment head, which abuts against the bottom of the floating pressure ring. By rotating the dedicated adjustment head, the floating pressure ring is lifted up.

[0007] Furthermore, the concave mold and the upper template are fastened together by a first fastening bolt, which is placed in a T-groove inside the upper template.

[0008] Furthermore, the upper template is provided with first lifting screws for hoisting at both the left and right ends.

[0009] Furthermore, the contact gap between the floating pressure ring and the die pressing surface is ≤0.20mm.

[0010] Furthermore, the lower template and the punch are fastened together by a second fastening bolt, which is placed in a T-slot inside the lower template.

[0011] Furthermore, the lower template is provided with second lifting screws at both the left and right ends for hoisting.

[0012] Furthermore, the dedicated adjusting head includes an adjusting stud inserted into the top of the movable push rod; the adjusting stud includes an upper part and a lower part, with the diameter of the upper part being smaller than that of the lower part; the lower part of the adjusting stud is provided with a mounting hole for insertion into the top of the movable push rod, and the upper part of the adjusting stud is provided with an external thread; the upper part of the adjusting stud is threadedly connected to a rotating adjusting head, and the rotating adjusting head is connected to the external thread of the upper part of the adjusting stud through the internal thread of the inner hole.

[0013] This invention also designs a forming method suitable for small-diameter, thin-walled ellipsoids, applicable to the aforementioned deep drawing die for small-diameter, thin-walled ellipsoids, characterized by including the following steps: S1) Assemble the upper mold assembly and fasten the upper mold assembly to the upper slide block of the hydraulic press; Assemble the lower mold assembly, hoist and fix the lower mold assembly on the upper surface of the lower platform of the hydraulic press, so that the movable ejector rod passes through the lower template and punch, and ensure that the special adjusting head abuts against the bottom of the floating pressure ring, so as to support the floating pressure ring to move up and down. S2) Open the upper slide of the hydraulic press, which drives the upper mold assembly to move upward and separate from the floating pressure ring; S3) Place the cold-rolled steel sheet deep-drawn billet on the upper plane of the floating blank holder; S4) Start the hydraulic press and move the upper slide downwards, so that the die pressing surface contacts the blank. The die and the floating blank holder press the blank together. The upper slide of the hydraulic press applies pressure and moves downwards. The die drives the blank to undergo plastic deformation, so that the blank gradually fits the surface of the punch until it is completely fitted to the punch surface. The floating blank holder moves down synchronously as the deformation process progresses until it contacts the stroke limit post, thus obtaining an ellipsoidal part with the same surface as the punch.

[0014] Furthermore, in S2), after the floating pressure ring is separated from the upper die assembly, the rotating adjustment head of the special adjustment head is rotated to adjust the height and parallelism of the floating pressure ring, and control the contact gap between the floating pressure ring and the die pressing surface to be ≤0.20mm.

[0015] Furthermore, in S2), drawing oil is applied to the upper plane of the floating blank holder; in S3), drawing oil is applied to the contact area between the upper surface of the blank and the lower plane of the die.

[0016] The advantages of this invention are: 1. This invention can complete the plastic forming of cold-rolled steel sheet in one step. The ultra-high strength thin-walled ellipsoid obtained by the deep drawing method has a small gap between the inner surface and the template, high dimensional accuracy, and excellent matching with the spun cylinder welding assembly. 2. This invention can efficiently complete the processing and production of large batches of ellipsoids, and each piece has high dimensional accuracy and excellent quality stability and consistency; 3. The process of this invention is simple and the material utilization rate is high. It not only reduces production costs but also shortens the production cycle, and improves efficiency by more than 20 times compared with the machined ellipsoid method. This invention relates to a deep-drawing die and forming method for small-diameter, thin-walled ellipsoids. It can cold-form thin-walled ellipsoids from ultra-high-strength steel plates. The process is simple, with high material utilization, which not only reduces production costs but also shortens the production cycle. The resulting thin-walled ellipsoid has a small gap between its inner surface and the template, high dimensional accuracy, and stable and consistent quality, avoiding local bulging and wrinkling problems. It has excellent application prospects in the production of solid rocket engine combustion chamber shell parts in the aerospace field. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the deep drawing die for small-diameter, thin-walled ellipsoids in this invention. Figure 2 for Figure 1 Enlarged view of point I in the middle; Figure 3 for Figure 1 Enlarged structural diagram of components of a medium ellipsoidal body; In the diagram: Upper mold assembly 1 (not shown), Lower mold assembly 2 (not shown), Ejection mechanism 3 (not shown), Ellipsoidal component 4; The upper mold assembly 1 includes: upper template 1-1, die 1-2, first fastening bolt 1-3, first lifting screw 1-4; The lower mold assembly 2 includes: lower platform 2-1, lower template 2-2, punch 2-3, second lifting screw 2-4, stroke limit post 2-5, floating pressure ring 2-6, and second fastening bolt 2-7; The ejection mechanism 3 includes: a hydraulic cushion top plate 3-1, a movable ejector rod 3-2, and a special adjusting head 3-3; The special adjustment head 3-3 includes: adjustment stud 3-31 and rotary adjustment head 3-32. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0020] This invention can achieve one-time deep drawing of sheet metal into small-diameter ellipsoids with diameters of Φ300mm to Φ600mm.

[0021] Example 1 A thin-walled ellipsoid of ultra-high strength steel with dimensions of 2.9 mm (thickness δ) × φ400 mm (outer diameter D) × 200 mm (depth h) was prepared.

[0022] like Figure 1 As shown, the present invention provides a deep drawing die suitable for small-diameter, thin-walled ellipsoids, used for forming thin-walled ellipsoids for engine combustion chamber housings, comprising an upper die assembly 1, a lower die assembly 2, and an ejection mechanism 3.

[0023] The upper mold assembly 1 includes an upper template 1-1 that is fastened to the upper slider of the hydraulic press. The lower end of the upper template 1-1 is fastened to a downward-opening concave mold 1-2. The left and right ends of the upper template 1-1 are respectively provided with first lifting screws 1-4 for hoisting.

[0024] The concave mold 1-2 and the upper template 1-1 are fastened together by a first fastening bolt 1-3, which is placed in a T-slot inside the upper template 1-1.

[0025] The upper mold assembly 1 moves up and down along with the slide block on the hydraulic press.

[0026] The lower mold assembly 2 includes a lower template 2-2 fixed on the upper surface of the lower platform 2-1 of the hydraulic press. A top-shaped punch 2-3 corresponding to the concave mold 1-2 is fixedly connected to the upper surface of the lower template 2-2. Stroke limiting posts 2-5 are respectively provided on both sides of the lower part of the top part of the punch 2-3. A floating pressure ring 2-6 is sleeved on the upper part of the top part of the punch 2-3, and the stroke limiting posts 2-5 are located below the floating pressure ring 2-6.

[0027] The floating pressure ring 2-6 moves up and down by the ejection mechanism 3. The lower stroke position of the floating pressure ring 2-6 is controlled by the stroke limit post 2-5 to control the drawing stroke.

[0028] The lower template 2-2 and the punch 2-3 are fastened together by a second fastening bolt 2-7, which is placed in a T-slot inside the lower template 2-2.

[0029] The lower template 2-2 is equipped with second lifting screws 2-4 at both its left and right ends for hoisting.

[0030] An ellipsoidal component 4 is provided between the concave mold 1-2 and the convex mold 2-3.

[0031] Preferably, the contact gap between the floating pressure ring 2-6 and the pressure surface of the die 1-2 is ≤0.20mm.

[0032] The ejection mechanism 3 includes a hydraulic pad top plate 3-1 located at the bottom of the lower platform 2-1 of the hydraulic press. Movable ejector rods 3-2 are respectively provided on the left and right sides inside the hydraulic pad top plate 3-1. The movable ejector rods 3-2 extend from the inside of the hydraulic pad top plate 3-1, through the lower platform 2-1 and the lower template 2-2 of the hydraulic press, until they penetrate the lower sides of the upper part of the punch 2-3 and extend to the bottom of the floating pressure ring 2-6.

[0033] The center of the movable push rod 3-2 is aligned with the pressure center of the hydraulic press.

[0034] The movable top rod 3-2 is equipped with a dedicated adjusting head 3-3 at its top, and the dedicated adjusting head 3-3 abuts against the bottom end of the floating pressure ring 2-6. By rotating the dedicated adjusting head 3-3, the dedicated adjusting head 3-3 can lift the floating pressure ring 2-6.

[0035] like Figure 2 As shown, the dedicated adjusting head 3-3 includes an adjusting stud 3-31 that is inserted into the top of the movable push rod 3-2. The adjusting stud 3-31 includes an upper part and a lower part, with the diameter of the upper part being smaller than that of the lower part. The lower part is provided with a mounting hole for insertion into the top of the movable push rod 3-2, and the upper part is provided with an external thread.

[0036] The upper part of the adjusting stud 3-31 is threadedly connected to a rotary adjusting head 3-32, which is connected to the external thread on the upper part of the adjusting stud 3-31 through the internal thread of its inner hole. By rotating the rotary adjusting head 3-32, the parallelism of the floating pressure ring 2-6 can be adjusted, thereby controlling the contact gap between the floating pressure ring 2-6 and the pressing surface of the die 1-2.

[0037] In this embodiment, the lower mounting hole of the adjusting stud 3-31 is consistent with the outer diameter of the movable push rod 3-2, maintaining a single-sided mounting gap of 0.15mm.

[0038] When the ejection mechanism 3 moves up and down by the piston of the hydraulic cushion ejection cylinder, it drives the movable ejector rod 3-2 and the special adjustment head 3-3 installed on the hydraulic cushion top plate 3-1 to move the floating pressure ring 2-6 up and down together.

[0039] This invention also designs a forming method suitable for small-diameter, thin-walled ellipsoids, applicable to the deep drawing die for the aforementioned small-diameter, thin-walled ellipsoids, comprising the following steps: S1) is the step for installing the deep drawing die: Assemble the upper mold assembly 1 and fasten it to the upper slide of the hydraulic press, so that the center of the upper mold assembly 1 coincides with the center of the hydraulic press.

[0040] Assemble the lower mold assembly 2, hoist and fix the lower mold assembly 2 onto the upper surface of the lower platform 2-1 of the hydraulic press, so that the movable push rod 3-2 passes through the lower template 2-2 and the punch 2-3, and ensure that the special adjusting head 3-3 abuts against the bottom end of the floating pressure ring 2-6, so as to support the floating pressure ring 2-6 to move up and down; at the same time, ensure that the center of the lower mold assembly 2 coincides with the center of the hydraulic press.

[0041] Rotate the rotating adjustment head 3-32 of the special adjustment head 3-3 to adjust the height and parallelism of the floating pressure ring 2-6, and control the contact gap between the floating pressure ring 2-6 and the pressing surface of the die 1-2 to be ≤0.20mm.

[0042] S2) Open the upper slide of the hydraulic press, drive the upper die assembly 1 to move upward and separate from the floating pressure ring 2-6. Lock the upper slide with an opening and closing gap of ≥600mm. Apply a layer of special deep drawing oil evenly to the upper surface of the floating pressure ring 2-6. S3) Place the cold-rolled steel sheet with a thickness of 2.9mm and an outer diameter of φ670mm on the upper plane of the floating blank holder 2-6, so that the center of the blank coincides with the center of the hydraulic press, and apply a layer of special deep drawing oil to the contact area (blank surface) between the upper surface of the blank and the lower plane of the die 1-2. S4) The upper slide of the hydraulic press moves downward, causing the blanking surface of the die 1-2 to contact the blank. The die 1-2 and the floating blank holder 2-6 press the blank together. The upper slide of the hydraulic press applies pressure and moves downward, causing the die 1-2 to plastically deform the blank, gradually making the blank fit with the surface of the punch 2-3 until it is completely fitted with the surface of the punch 2-3. The floating blank holder 2-6 moves downward synchronously as the deformation process progresses until it contacts the stroke limit post 2-5, completing the entire deep drawing process and obtaining an ellipsoidal part 4 with the same surface as the punch 2-3, namely an ultra-high strength steel thin-walled ellipsoid with specifications of 2.9mm (thickness δ) × φ400mm (outer diameter D) × 200mm (depth h).

[0043] As attached Figure 3 The figure shows a schematic diagram of the structure of the small-diameter, ultra-high-strength steel thin-walled ellipsoid prepared by the present invention. In the figure, D is the outer diameter of the ellipsoid, h is the depth of the ellipsoid, R is the fillet, and δ is the wall thickness of the ellipsoid.

[0044] Example 2 A thin-walled ellipsoid of ultra-high strength steel with dimensions of 2.6 mm (thickness) × φ500 mm (outer diameter) × 230 mm (depth h) was prepared.

[0045] The difference between Example 2 and Example 1 is that: A method for forming small-diameter, thin-walled ellipsoids is designed. In step S3), the deep-drawing blank is a cold-rolled steel sheet deep-drawing blank with a thickness of 2.6 mm and an outer diameter of φ730 mm. In step S4), the prepared ellipsoidal part 4 is an ultra-high-strength steel thin-walled ellipsoid with dimensions of 2.6 mm (thickness) × φ500 mm (outer diameter) × 230 mm (depth h).

[0046] Example 3 A thin-walled ellipsoid of ultra-high strength steel with dimensions of 3.0 mm (thickness) × φ600 mm (outer diameter D) × 250 mm (depth h) was prepared.

[0047] The difference between Example 3 and Example 1 is as follows: A method for forming small-diameter, thin-walled ellipsoids is designed. In step S3), the deep-drawing blank is a cold-rolled steel sheet deep-drawing blank with a thickness of 3.0 mm and an outer diameter of φ876 mm. In step S4), the prepared ellipsoidal part 4 is an ultra-high-strength steel thin-walled ellipsoid with dimensions of 3.0 mm (thickness) × φ600 mm (outer diameter D) × 250 mm (depth h).

[0048] This invention relates to a deep-drawing die and forming method for small-diameter, thin-walled ellipsoids. It can cold-form thin-walled ellipsoids from ultra-high-strength steel plates. The process is simple, with high material utilization, which not only reduces production costs but also shortens the production cycle. The resulting thin-walled ellipsoid has a small gap between its inner surface and the template, high dimensional accuracy, and stable and consistent quality, avoiding local bulging and wrinkling problems. It has excellent application prospects in the production of solid rocket engine combustion chamber shell parts in the aerospace field.

[0049] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A deep drawing die suitable for small-diameter, thin-walled ellipsoids, used for forming thin-walled ellipsoidal parts (4) for engine combustion chamber housings, characterized in that: It includes an upper mold assembly (1), a lower mold assembly (2), and an ejection mechanism (3); The upper mold assembly (1) includes an upper template (1-1) that is fastened to the upper slide of the hydraulic press, and a downward-opening concave mold (1-2) is fastened to the lower end of the upper template (1-1). The lower mold assembly (2) includes a lower template (2-2) fixed on the upper surface of the lower platform (2-1) of the hydraulic press. A type punch (2-3) corresponding to the concave mold (1-2) is fixedly connected to the upper surface of the lower template (2-2). Stroke limiting posts (2-5) are respectively provided on both sides of the lower part of the type punch (2-3). A floating pressure ring (2-6) is sleeved on the upper part of the type punch (2-3), and the stroke limiting posts (2-5) are located below the floating pressure ring (2-6). The ellipsoidal component (4) is placed between the die (1-2) and the punch (2-3), and the edge of the ellipsoidal component (4) is pressed between the floating pressure ring (2-6) and the pressure surface of the die (1-2); The ejection mechanism (3) includes a hydraulic pad top plate (3-1) located at the bottom of the lower platform (2-1) of the hydraulic press. Movable ejector rods (3-2) are respectively provided on the left and right sides inside the hydraulic pad top plate (3-1). The movable ejector rods (3-2) extend from inside the hydraulic pad top plate (3-1), through the lower platform (2-1) and the lower template (2-2) of the hydraulic press, until they penetrate the lower sides of the upper part of the punch (2-3) and extend to below the floating pressure ring (2-6). The top of the movable top rod (3-2) is provided with a special adjustment head (3-3), and the special adjustment head (3-3) abuts against the bottom of the floating pressure ring (2-6). By rotating the special adjustment head (3-3), the special adjustment head (3-3) lifts the floating pressure ring (2-6).

2. The deep drawing die for small-diameter, thin-walled ellipsoids according to claim 1, characterized in that: The concave mold (1-2) and the upper template (1-1) are fastened together by a first fastening bolt (1-3), which is placed in a T-slot inside the upper template (1-1).

3. The deep drawing die for small-diameter, thin-walled ellipsoids according to claim 2, characterized in that: The upper template (1-1) is provided with first lifting screws (1-4) at both the left and right ends for hoisting.

4. The deep drawing die for small-diameter, thin-walled ellipsoids according to claim 1, characterized in that: The contact gap between the floating pressure ring (2-6) and the pressing surface of the die (1-2) is ≤0.20mm.

5. The deep drawing die for small-diameter, thin-walled ellipsoids according to claim 4, characterized in that: The lower template (2-2) and the punch (2-3) are fastened together by a second fastening bolt (2-7), which is placed in a T-slot inside the lower template (2-2).

6. The deep drawing die for small-diameter, thin-walled ellipsoids according to claim 5, characterized in that: The lower template (2-2) is equipped with second lifting screws (2-4) at both the left and right ends for hoisting.

7. The deep drawing die for small-diameter, thin-walled ellipsoids according to claim 1, characterized in that: The special adjusting head (3-3) includes an adjusting stud (3-31) inserted into the top of the movable push rod (3-2); the adjusting stud (3-31) includes an upper part and a lower part, and the diameter of the upper part is smaller than that of the lower part. The lower part of the adjusting stud (3-31) is provided with a mounting hole for insertion into the top of the movable push rod (3-2), and the upper part of the adjusting stud (3-31) is provided with an external thread; the upper part of the adjusting stud (3-31) is threadedly connected to a rotating adjusting head (3-32), and the rotating adjusting head (3-32) is connected to the external thread on the upper part of the adjusting stud (3-31) through the internal thread of its inner hole.

8. A forming method for small-diameter, thin-walled ellipsoids, applicable to the deep drawing die for small-diameter, thin-walled ellipsoids as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1) Assemble the upper mold assembly (1) and fasten the upper mold assembly (1) to the upper slide of the hydraulic press; Assemble the lower mold assembly (2), hoist and fix the lower mold assembly (2) on the upper surface of the lower platform (2-1) of the hydraulic press, so that the movable push rod (3-2) passes through the lower template (2-2) and the punch (2-3), and ensure that the special adjusting head (3-3) abuts against the bottom end of the floating pressure ring (2-6) to support the floating pressure ring (2-6) to move up and down; S2) Open the upper slide of the hydraulic press, drive the upper mold assembly (1) to move upward, and separate it from the floating pressure ring (2-6); S3) Place the cold-rolled steel sheet deep-drawn billet on the upper plane of the floating blank holder (2-6); S4) Start the hydraulic press and move the upper slide downwards, so that the die (1-2) pressing surface contacts the blank. The die (1-2) and the floating blank holder (2-6) press the blank together. The upper slide of the hydraulic press applies pressure and moves downwards. The die (1-2) drives the blank to undergo plastic deformation, so that the blank gradually fits the surface of the punch (2-3) until it is completely fitted to the surface of the punch (2-3). The floating blank holder (2-6) moves down synchronously as the deformation process proceeds until it contacts the stroke limit post (2-5) and is in place, so as to obtain an ellipsoidal part (4) with the same surface as the punch (2-3).

9. The forming method for small-diameter, thin-walled ellipsoids according to claim 8, characterized in that: In S2), after the floating pressure ring (2-6) is separated from the upper mold assembly (1), rotate the rotating adjustment head (3-32) of the special adjustment head (3-3) to adjust the height and parallelism of the floating pressure ring (2-6) and control the contact gap between the floating pressure ring (2-6) and the pressing surface of the die (1-2) to be ≤0.20mm.

10. The forming method for small-diameter, thin-walled ellipsoids according to claim 9, characterized in that: In S2), deep drawing oil is applied to the upper plane of the floating blank holder (2-6); in S3), deep drawing oil is applied to the contact area between the upper surface of the blank and the lower plane of the die (1-2).

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