An ultrasonic-assisted radial zoned variable blank holder force drawing device and method

Abstract

An ultrasonic-assisted radially zoned variable blank holder force deep drawing device and method belongs to the field of sheet metal deep drawing. The device includes modular blank holder rings, independent hydraulic drive units, ultrasonic vibration auxiliary devices, upper die base, lower die base, punch, and die. The modular blank holder rings are circumferentially integral and radially replaceable structures, consisting of at least two sets of concentric circular ring blank holder rings. The independent hydraulic drive unit uses hollow piston hydraulic cylinders, with each cylinder arranged radially nested, the outer hollow area accommodating the inner hydraulic cylinders, achieving coaxial integration. Each piston rod has built-in pressure and displacement sensors, enabling independent real-time control of the blank holder force. The ultrasonic vibration auxiliary device is integrated into each blank holder ring, allowing for independent application of ultrasonic friction reduction in different zones. The upper die base has lead wire notches for oil pipes and cables. This invention achieves localized friction reduction and differentiated blank holder force through structure-force-energy field coordinated control, improving forming limits and wall thickness uniformity, and reducing die change time and costs.

Description

Technical Field

[0001] This invention belongs to the field of metal sheet deep drawing equipment, specifically relating to a deep drawing die pressing device, which is particularly suitable for deep drawing processing of lightweight, high-strength thin sheet materials such as aluminum alloys and high-temperature alloys. Background Technology

[0002] With the increasing demand for lightweight materials in the aerospace and new energy vehicle sectors, lightweight, high-strength sheet metal such as aluminum alloys and high-temperature alloys are widely used in the production of thin-walled deep-drawn components. During the sheet metal deep-drawing process, there are significant differences in the material flow resistance in the radial regions of the flange—the outer edge metal undergoes circumferential compression first and flows inward, making it prone to wrinkling; the inner edge material faces the risk of excessive thinning or even cracking. This differentiated flow characteristic places drastically different requirements on the radial distribution of the blank holder force.

[0003] Traditional deep drawing dies use an integral blank holder ring to apply a constant blank holder force across the entire flange area. If the blank holder force is too large, material flow in the inner edge area is obstructed, leading to excessive thinning or even tearing of the sidewalls; if the blank holder force is too small, wrinkling cannot be suppressed in the outer edge area. This "one-size-fits-all" pressure application method cannot adapt to the differentiated needs of the inner and outer flange areas, resulting in a narrow process window. This is a fundamental contradiction that has long remained unresolved in the field of deep drawing.

[0004] To resolve the aforementioned contradictions, the zoning variable pressure edge force technology has emerged. Existing zoning schemes are mainly divided into two categories:

[0005] One method is the circumferentially segmented splicing type. The pressure ring is divided into multiple independent pressure blocks along the circumference, and each block can be pressured independently. Although this method achieves zoned control of force, splicing gaps inevitably exist between the pressure blocks. The board at these gaps lacks pressure restraint and is very prone to instability and wrinkling under tangential compressive stress, becoming a new weak point.

[0006] The second method is radially zoned elastomer adjustment. The blank holder ring is divided into inner and outer rings radially, with a polyurethane rubber elastomer placed beneath each ring. The ratio of blank holder force in each region is preset by changing the number of elastomers. While this method avoids the circumferential gap problem, it has two fundamental limitations: 1) The blank holder force provided by the elastomer is passive and preset, and cannot be actively adjusted in real time according to the punch stroke during deep drawing; 2) The blank holder forces in each region are coupled, and adjusting one region inevitably affects the pressure distribution in other regions, making it difficult to achieve truly independent and precise control.

[0007] In the field of ultrasonic-assisted forming, existing technologies mostly use uniform vibration excitation across the entire area, that is, applying the same ultrasonic vibration to the entire pressure ring, which cannot make differentiated adaptations for the different friction states of the outer and inner edges of the flange.

[0008] From a theoretical perspective, synergistically coupling "regional variable blank holder force" and "regional ultrasonic assistance" is the optimal technical path to simultaneously solve differentiated flow control and global drag reduction and plasticization. However, there is currently no integrated solution for synergistic coupling of the two technologies. The fundamental reason lies in the physical constraints of structural space: if traditional piston-type hydraulic cylinders are used to independently provide blank holder force to each radial zone, multiple hydraulic cylinders need to be arranged side by side within the limited upper mold space. Since each blank holder ring has a concentric nested structure, its driving element must be arranged within the same circumferential area. However, the axial dimension and radial space occupied by traditional hydraulic cylinders are relatively large, making it impossible to simultaneously accommodate multiple sets of independent hydraulic cylinders and ensure their independent stroke and pressure control within the limited mold space. This is the fundamental structural obstacle preventing the synergistic integration of regional variable blank holder force and regional ultrasonic assistance. Summary of the Invention

[0009] This invention provides an ultrasonic-assisted radially partitioned variable blank holder force deep drawing device and method. It mainly divides the blank holder ring radially according to the different blank holder forces required for different parts in the diameter direction of the circular part, so as to solve the wrinkling and cracking problems caused by unsuitable blank holder force during the deep drawing process. At the same time, it reduces the frictional resistance of each area by independent ultrasonic vibration of each partition, so as to achieve coordinated control of structure-force-energy field.

[0010] To achieve the above objectives, the present invention adopts the following technical solution.

[0011] The present invention discloses an ultrasonic-assisted radially partitioned variable blank holder drawing device, comprising an ultrasonic vibration auxiliary device, a modular blank holder ring, an independent hydraulic drive unit, an upper die base, a lower die base, a punch, and a die.

[0012] The modular blank holder is a replaceable blank holder structure that is circumferentially integral and radially partitioned. It consists of multiple sets of concentric circular blank holders arranged independently along the radial direction of the workpiece. Each set of circular blank holders is independent of each other and not rigidly connected. All concentric circular blank holders are arranged coaxially with the die. The modular blank holder integrates an ultrasonic vibration auxiliary device.

[0013] The independent hydraulic drive unit includes independent hydraulic devices that correspond one-to-one with each concentric ring pressure ring. Each independent hydraulic device adopts a hollow piston hydraulic cylinder structure. The hydraulic cylinder body of this structure is in the shape of a concentric ring. The hydraulic cylinders of each section are arranged in a radially nested manner. The hollow area in the center of the outer hydraulic cylinder is used to accommodate the adjacent inner hydraulic cylinder, thereby realizing the coaxial integrated arrangement of multiple sets of independent hydraulic cylinders within the limited upper mold base space.

[0014] The output end of the hydraulic cylinder is connected to the circular pressure ring, enabling independent stroke and independent pressure adjustment control for each pressure ring. The independent hydraulic device is connected to an independent pressure regulating valve and has a built-in independent displacement sensor. It can set the pressure force and pressing stroke of each zone individually according to the deformation differences in different radial areas of the workpiece, so as to achieve circumferential overall forming and radial zone variable pressure forming of the workpiece.

[0015] As a further limitation of the above technical solution: each independent hydraulic device includes a hydraulic cylinder inner shell, a hydraulic piston rod, a hydraulic cylinder outer shell, and a hydraulic cylinder end cap; the hydraulic cylinder inner shell and the hydraulic cylinder outer shell are fixedly connected by threads, the hydraulic piston rod is placed between the hydraulic cylinder inner shell and the hydraulic cylinder outer shell, and the hydraulic cylinder end cap is fixedly connected to the hydraulic cylinder outer shell by threads; each independent hydraulic device is fixedly installed on the upper mold base through its respective hydraulic cylinder outer shell, and all are arranged coaxially with the punch.

[0016] Each of the hydraulic piston rods has a built-in pressure sensor and a displacement sensor. The pressure sensor and displacement sensor are used to monitor the blank holder force and pressing stroke of the corresponding zone in real time, and control the blank holder force of each zone based on the punch stroke feedback.

[0017] The ultrasonic vibration auxiliary device includes ultrasonic vibration units corresponding to each concentric circular pressure ring. Each ultrasonic vibration unit includes an ultrasonic transducer and an amplitude transformer. The ultrasonic transducer is fixedly installed in the mounting groove on the back of the circular pressure ring. One end of the amplitude transformer is connected to the ultrasonic transducer, and the other end is fixed to the center of the back of the circular pressure ring through a threaded connection, so as to transmit ultrasonic vibration to the circular pressure ring and act on the workpiece through the working surface. Each group of pressure rings is matched with an independent ultrasonic start / stop and power adjustment unit to realize independent ultrasonic vibration output in different zones.

[0018] The upper mold base has a lead wire notch, through which the hydraulic oil pipes of each zone hydraulic device and the connecting cables of the ultrasonic transducer are led out to the top of the upper mold base.

[0019] The die cavity is installed in the groove of the lower die base and is installed coaxially with the groove; the punch is assembled coaxially with the axis of the die cavity; the independent hydraulic device is installed on the upper die base.

[0020] Preferably, the radially partitioned pressing edge assembly includes at least two concentric circular pressing edge rings.

[0021] Preferably, the modular pressure ring can be adapted to replace concentric ring pressure ring combinations of different specifications according to different diameter plates.

[0022] The modular deep drawing method for radially partitioned variable pressure edge force described in this invention, using the aforementioned device, includes the following steps:

[0023] (1) Fix the die on the lower die base, select the appropriate pressure ring according to the diameter of the plate to be processed, place the metal plate blank between the die and the modular pressure ring, and ensure that the blank and the die are coaxial.

[0024] (2) Start the hydraulic drive unit, and each zone pressing ring applies an initial pressing force to the sheet metal to press the sheet metal blank tightly;

[0025] (3) The punch presses down to start drawing the metal sheet blank. The blank holders in each zone adjust the blank holder force independently according to the punch stroke to suppress wrinkling and cracking of the sheet in the flange area.

[0026] (4) Activate the ultrasonic vibration auxiliary module to apply ultrasonic vibrations of different frequencies and powers to the pressure rings of each zone independently, thereby reducing the frictional resistance between the sheet metal and the pressure rings and the die.

[0027] (5) After the deep drawing is completed, stop the ultrasonic vibration, raise the blank holder, and take out the formed workpiece.

[0028] Preferably, in step (3), the blank holder rings of each zone adjust the blank holder force independently according to the punch stroke. This is achieved by real-time monitoring and feedback control of pressure sensors and displacement sensors integrated in an independent hydraulic device.

[0029] Preferably, the ultrasonic vibration with different frequencies and powers applied independently to the pressure rings of each partition in step (4) is set according to the different material flow states and friction characteristics of the flange areas corresponding to each partition.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) A hollow piston hydraulic cylinder structure is adopted, and the hydraulic cylinders of each section are arranged in a radial nested manner. The hollow area in the center of the outer hydraulic cylinder is used to accommodate the adjacent inner hydraulic cylinder. Multiple independent hydraulic cylinders can be coaxially integrated in the limited upper mold base space. This breaks through the structural barrier that traditional hydraulic cylinders cannot achieve multiple independent drives in the concentric ring nested structure due to space limitations. This enables the synergistic coupling of the section pressing force and the section ultrasonic assistance to be realized in the physical structure.

[0032] (2) Structure-force-energy field coordinated control: The present invention organically integrates the radial partitioned variable pressure edge force structure with partitioned independent ultrasonic vibration excitation, which can actively regulate the flow of slab flange material in partitioned areas, simultaneously realize local friction reduction and differentiated pressure edge, effectively avoid or suppress wrinkling and cracking of parts, and significantly improve forming limit and wall thickness uniformity.

[0033] (3) Optimized edge pressing structure with circumferential integral and radial partition: The concentric ring nested edge pressing structure is adopted. The radial gap between the inner and outer ring edge pressing rings is perpendicular to the radial flow direction of the material. The impact on the material flow is much smaller than the splicing gap of the circumferential segment. The ring edge pressing ring ensures the continuous support of the material in the edge pressing area and effectively prevents the material from deforming and becoming unstable at the gap.

[0034] (4) Independent ultrasonic vibration friction reduction in each zone: Each zone of the pressure ring can be independently subjected to ultrasonic vibration of different frequencies and powers, which can be precisely controlled according to the different friction states and material flow requirements of each zone. Compared with uniform ultrasonic vibration in the whole area, it has better targeting.

[0035] (5) Modular and replaceable structure: The blank holder adopts a modular and detachable structure, which can be adapted to the processing of cylindrical parts of different diameters, greatly reducing the mold change time and cost. The mold versatility and process adjustability are significantly better than the traditional integral blank holder deep drawing scheme.

[0036] (6) Real-time precise control: Each independent hydraulic device integrates pressure sensor and displacement sensor, which can adjust the blank holder force of each zone in real time according to the punch stroke, so as to realize precise closed-loop control of variable blank holder force.

[0037] (7) A lead wire notch is opened on the upper mold base. The hydraulic oil pipe and transducer cable are led out through the notch in a unified manner, which can effectively avoid interference of the cable during the mold operation. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the mold operation of the ultrasonic-assisted radially partitioned variable pressure edge force deep drawing device of the present invention;

[0039] Figure 2 This is a schematic diagram of the radial partitioning of the pressure ring of the present invention;

[0040] Figure 3 This is a schematic diagram of the overall mold structure of the present invention;

[0041] Figure 4 This is a schematic diagram showing the positions of the independent hydraulic device, ultrasonic device, and sensor within this invention;

[0042] Figure 5 This is a schematic diagram showing the positions of the external independent hydraulic device, ultrasonic device, and sensor of the present invention.

[0043] The meanings of the markings in the diagram are as follows:

[0044] 1-Outer hydraulic cylinder inner shell; 2-Outer hydraulic piston rod; 3-Outer hydraulic cylinder outer shell; 4-Outer hydraulic cylinder end cap; 5-Upper mold base; 6-Outer pressure ring; 7-Inner hydraulic cylinder inner shell; 8-Inner hydraulic cylinder outer shell; 9-Inner hydraulic piston rod; 10-Inner hydraulic cylinder end cap; 11-Inner pressure ring; 12-Punch; 13-Sheet metal; 14-Lower mold base; 15-Support column; 16-Die; 17-Displacement and pressure sensor; 18-Inner ultrasonic vibration auxiliary module; 19-Outer ultrasonic vibration auxiliary module. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] The basic idea of ​​this invention is to address problems such as uneven material flow, edge wrinkling, excessive wall thinning, and low forming limits in the deep drawing of rotary thin sheet flanges by integrating ultrasonic vibration to control friction and radially partitioned variable blank holder force regulation. A modular concentric ring combined segmented blank holder structure is used as the core execution unit, dividing the flange radially into two or more independent annular partitions. Each partition is connected to an independent hydraulic cylinder, and the pressure can be adjusted according to the punch stroke. Simultaneously, an ultrasonic vibration auxiliary device is integrated into the corresponding partition blank holder module, utilizing the ultrasonic interface friction reduction effect to reduce the frictional resistance between the sheet metal and the blank holder / die contact surface. The core structural basis for achieving the above synergistic coupling scheme lies in the fact that each independent hydraulic device adopts a hollow piston-type hydraulic cylinder structure, arranged radially in a nested manner. The hollow area in the center of the outer hydraulic cylinder is used to accommodate the adjacent inner hydraulic cylinder, and the hollow structure of the inner hydraulic cylinder provides clearance space for the punch extension and retraction, thus achieving the coaxial integrated arrangement of multiple independent hydraulic cylinders within the limited upper die holder space. The device's blank holder ring adopts a modular and detachable structure, which can be adapted to the processing of cylindrical parts of different diameters. The mold versatility and process adjustability are significantly better than the traditional integral blank holder deep drawing solution.

[0047] (I) Device Structure

[0048] The overall structure of this invention is as follows Figure 1 and Figure 3As shown. The inner shell 1 and outer shell 3 of the outer hydraulic cylinder are connected by threads. The outer hydraulic piston rod 2 is placed between the inner shell 1 and outer shell 3. The outer hydraulic cylinder end cap 4 is connected to the outer shell 3 by threads. The inner shell 1, outer hydraulic piston rod 2, outer shell 3, and outer shell 4 together form an independent external hydraulic device, which is fixed to the upper mold base 5 by the outer shell 3. The inner shell 7 and outer shell 8 of the inner hydraulic cylinder are connected by threads. The inner hydraulic piston rod 9 is placed between the inner shell 7 and outer shell 8. The inner shell 10 is connected to the outer shell 8 by threads. The inner shell 7, inner hydraulic piston rod 9, inner shell 8, and inner shell 10 together form an independent internal hydraulic device, which is fixed to the upper mold base 5 by the inner shell 8 and is coaxially assembled with the independent external hydraulic device. The die 16 is fixed in the groove of the lower mold base 14. The outer pressure ring 6 and the inner pressure ring 11 are fixed to the outer hydraulic piston rod 2 and the inner hydraulic piston rod 9 respectively by threaded connection. The upper mold base 5 and the lower mold base 14 are fixedly connected by the support column 15.

[0049] The outer hydraulic piston rod 2 and the inner hydraulic piston rod 9 are equipped with pressure and displacement sensors 17, which can adjust the pressure of the blank holder ring according to the downward stroke of the punch 12. The inner blank holder ring 11 and the outer blank holder ring 6 respectively integrate an inner ultrasonic vibration auxiliary module 18 and an outer ultrasonic vibration auxiliary module 19, which can apply ultrasonic vibrations of different frequencies. Since the hydraulic device and the ultrasonic vibration auxiliary device are independent devices, precise control of forming can be achieved by changing the blank holder force and the ultrasonic vibration frequency.

[0050] The upper mold base 5 has a lead wire notch (not shown in the figure). The hydraulic oil pipes of each section hydraulic device and the connecting cables of the ultrasonic transducer are led out through this notch to the top of the upper mold base to avoid interference between the cables during the mold operation.

[0051] (II) Working Methods

[0052] The modular deep drawing method with ultrasonic-assisted radial partitioned variable pressure edge force provided by the present invention, using the above-mentioned device, includes the following steps:

[0053] Step 1: Mold Installation and Blank Positioning

[0054] Fix the die 16 on the lower die base 14. Select the appropriate outer pressure ring 6 and inner pressure ring 11 according to the diameter of the sheet metal 13 to be processed, and install them on the corresponding piston rods. Place the metal sheet blank between the die 16 and the outer pressure ring 6 and inner pressure ring 11, ensuring that the blank and the die are coaxial.

[0055] Step 2: Initial edge pressing

[0056] When the hydraulic system is started, the external independent hydraulic device and the internal independent hydraulic device apply initial blanking force to the sheet metal 13 through the external blanking ring 6 and the internal blanking ring 11, respectively, and the metal sheet blank is pressed between the die 16 and the blanking ring.

[0057] Step 3: Variable blank holder force deep drawing

[0058] The punch 12 presses down to begin drawing the sheet metal blank. During the drawing process, the outer pressure ring 6 and the inner pressure ring 11 independently adjust their pressure according to the stroke of the punch 12—the outer pressure ring 6 applies a pressure force suitable for suppressing wrinkling in the outer edge area, while the inner pressure ring 11 applies a pressure force suitable for preventing excessive thinning in the inner edge area. The pressure force in each zone changes dynamically with the punch stroke, suppressing wrinkling and cracking of the sheet metal in the flange area and ensuring smooth drawing.

[0059] Step 4: Zonal Ultrasonic Vibration Assistance

[0060] During deep drawing, the ultrasonic vibration auxiliary device is activated. The inner ultrasonic vibration auxiliary module 18 and the outer ultrasonic vibration auxiliary module 19 apply ultrasonic vibrations of different frequencies and powers to the inner blank holder 11 and the outer blank holder 6, respectively. The ultrasonic vibrations are transmitted to the working surface of the blank holder through the transducer and amplitude transformer, reducing the frictional resistance between the sheet metal and the blank holder and die, promoting material flow, and reducing the forming load.

[0061] Step 5: Pick up the package

[0062] After the deep drawing is completed, the ultrasonic vibration is stopped, the blank holder is raised with the hydraulic cylinder, the formed workpiece is taken out, and the forming process is completed.

[0063] The above embodiments use two sets of annular pressure rings (outer annular pressure ring and inner annular pressure ring) as examples for illustration, but the scope of protection of this invention is not limited to two sets. Those skilled in the art can expand the number of annular pressure rings to three or more sets according to the workpiece size and process requirements. Correspondingly, the number of independent hydraulic devices and ultrasonic vibration units also increases accordingly. During expansion, the hydraulic cylinders in each zone are still arranged in a radially nested manner, with the central hollow area of ​​the outer hydraulic cylinder used to accommodate the adjacent inner hydraulic cylinder; each annular pressure ring is still connected to the output end of the corresponding hydraulic cylinder and is equipped with an independent pressure regulating valve, pressure sensor, displacement sensor, and ultrasonic vibration unit. Its nesting arrangement and working principle are exactly the same as the two sets of embodiments described above.

[0064] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultrasonic-assisted radially partitioned variable blank holder drawing device, comprising an ultrasonic vibration assist device, a modular blank holder ring, an independent hydraulic drive unit, an upper die base, a lower die base, a punch, and a die, characterized in that: The modular pressure ring is a replaceable pressure ring structure that is circumferentially integral and radially partitioned. It consists of at least two sets of concentric circular pressure rings arranged independently along the radial direction of the workpiece. Each set of circular pressure rings is independent of each other and not rigidly connected to each other. All concentric circular pressure rings are arranged coaxially with the die. The independent hydraulic drive unit includes independent hydraulic devices corresponding to each concentric ring pressure plate. Each independent hydraulic device adopts a hollow piston hydraulic cylinder structure. The body of the hydraulic cylinder is in the shape of a concentric ring. The hydraulic cylinders of each section are arranged in a radially nested manner. The central hollow area of ​​the outer hydraulic cylinder is used to accommodate the adjacent inner hydraulic cylinder. The output end of the hydraulic cylinder is connected to the ring pressure plate to realize independent stroke and independent pressure adjustable control of a single pressure plate. The hydraulic circuit of the independent hydraulic device is equipped with an independent pressure regulating valve, and the output end has a built-in pressure sensor and displacement sensor for real-time monitoring of the pressure force and pressing stroke of the corresponding section, and controlling the pressure force of each section according to the punch stroke feedback. The ultrasonic vibration auxiliary device includes ultrasonic vibration units that correspond one-to-one with each concentric circular pressure ring. Each ultrasonic vibration unit includes an ultrasonic transducer and an amplitude transformer. The ultrasonic transducer is fixedly installed in the mounting groove on the back of the circular pressure ring. One end of the amplitude transformer is connected to the ultrasonic transducer, and the other end is fixed to the center of the back of the circular pressure ring, transmitting ultrasonic vibration to the circular pressure ring and acting on the workpiece through the working surface. Each group of pressure rings is matched with an independent ultrasonic start / stop and power adjustment unit to achieve independent ultrasonic vibration output in different zones.

2. The ultrasonic-assisted radially partitioned variable pressure edge force deep drawing device according to claim 1, characterized in that, Each independent hydraulic device includes a hydraulic cylinder inner shell, a hydraulic piston rod, a hydraulic cylinder outer shell, and a hydraulic cylinder end cap; the hydraulic cylinder inner shell is fixedly connected to the hydraulic cylinder outer shell, the hydraulic piston rod is placed between the hydraulic cylinder inner shell and the hydraulic cylinder outer shell, and the hydraulic cylinder end cap is fixedly connected to the hydraulic cylinder outer shell; the pressure sensor and displacement sensor are built into the hydraulic piston rod.

3. The ultrasonic-assisted radially partitioned variable pressure edge force deep drawing device according to claim 2, characterized in that, The fixed connection is a threaded connection.

4. The ultrasonic-assisted radially partitioned variable pressure edge force deep drawing device according to claim 1, characterized in that, The upper mold base has a lead wire notch, through which the hydraulic oil pipes of each zone hydraulic device and the connecting cables of the ultrasonic transducer are led out to the top of the upper mold base.

5. The ultrasonic-assisted radially partitioned variable pressure edge force deep drawing device according to claim 1, characterized in that, The die cavity is installed in the groove of the lower die base and is installed coaxially with the groove; the punch is assembled coaxially with the axis of the die cavity; the independent hydraulic device is installed on the upper die base.

6. The ultrasonic-assisted radially partitioned variable pressure edge force deep drawing device according to claim 1, characterized in that, The modular pressure ring can be adapted to different diameter plates by replacing concentric ring pressure ring combinations of different specifications.

7. A method for deep drawing with ultrasonic-assisted radially partitioned variable pressure edge force, employing the apparatus described in any one of claims 1 to 6, characterized in that... Includes the following steps: (1) Fix the die on the lower die base, select the appropriate pressure ring according to the diameter of the plate to be processed, place the metal plate blank between the die and the modular pressure ring, and ensure that the blank and the die are coaxial. (2) Start the hydraulic drive unit, and each zone of the pressing ring applies an initial pressing force to the sheet metal to press the sheet metal blank tightly; (3) The punch presses down to start drawing the metal sheet blank. The blank holders in each zone adjust the blank holder force independently according to the punch stroke to suppress wrinkling and cracking of the sheet in the flange area. (4) Activate the ultrasonic vibration auxiliary device to apply ultrasonic vibrations of different frequencies and powers to the pressure rings of each zone independently to reduce the frictional resistance between the plate and the pressure rings and the die. (5) After the deep drawing is completed, stop the ultrasonic vibration, raise the blank holder, and take out the formed workpiece.

8. The ultrasonic-assisted radially partitioned variable pressure edge force deep drawing method according to claim 7, characterized in that, The independent adjustment of the blank holder force of each partition in step (3) according to the punch stroke is achieved by real-time monitoring and feedback control by pressure sensor and displacement sensor integrated in independent hydraulic device.

9. The ultrasonic-assisted radially partitioned variable pressure edge force deep drawing method according to claim 7, characterized in that, The ultrasonic vibration with different frequencies and powers applied to each zone pressure ring in step (4) is set according to the different material flow states and friction characteristics of the flange areas corresponding to each zone.

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