A forming device and method for coordinated regulation of plate partition edge pressing and rapid heating

Abstract

This invention discloses a forming device and method for synergistic control of sheet metal partitioned edge pressing and rapid heating. Utilizing the Joule heating effect generated when a pulsed current passes through metal, electrodes built into the partitioned edge pressing device enable rapid heating and temperature control of the forming blank in different regions. This allows for the design of the partitioned edge pressing device's shape and size based on the specific shape characteristics of the part. Furthermore, the device synergistically controls the edge pressing force and forming temperature of different partitioned blanks during the forming process, reducing work hardening and improving material fluidity, thereby achieving high-quality forming of complex-shaped thin-walled components. The comprehensive utilization of the rapid heating and high plastic deformation capabilities of the metal sheet assisted by current, along with the design concept and tooling structure featuring independent partitioned edge pressing force and forming temperature control, makes this patent inventive and novel in the field of high-quality, precise forming of thin-walled metal components.

Description

Technical Field

[0001] This invention relates to the field of precision plastic forming technology for thin-walled components, and in particular to a forming apparatus and method for synergistic control of sheet metal partitioning and rapid heating. Background Technology

[0002] Metal stamping is a manufacturing technique that applies load to sheet metal using a forming die, causing plastic deformation and forming a thin-walled component with the die's surface shape. During the forming process, the metal material on the outer side of the die surface flows into the die cavity under the pressure of the punch, along the transition chamfer at the die opening. At this location, the sheet metal is in a complex stress state macroscopically, especially the compressive stress in the tangential direction, which easily leads to an increase in blank thickness. Microscopically, with the accumulation of plastic deformation, the dislocation density continuously increases, exacerbating work hardening. Furthermore, the unformed areas also deform due to material flow, generating complex stress states. These factors hinder further material flow and easily lead to instability phenomena such as wrinkling or cracking.

[0003] Based on the specific shape of the formed part and the material flow characteristics during plastic deformation, optimizing the initial blank shape can effectively mitigate the impact of interactions between unformed areas on material flow. Furthermore, using a zoned control method for blank holder force can optimize material flow behavior by adjusting the magnitude of the blank holder force according to the stress state of different regions, which is also an effective method to improve the forming limit of the material and the uniformity of the part's wall thickness distribution. However, both of these methods only weaken dislocation pile-up and work hardening phenomena to a certain extent at the unformed area and the chamfer transition between the die and the chamfer. Increasing the forming temperature of the unformed area, thereby reducing the dislocation density inside the metal material and improving the work hardening phenomenon of the sheet metal, can effectively promote the plastic flow of the material during forming, which is of great significance for improving the forming limit of the material and the uniformity of the part's wall thickness.

[0004] In existing sheet metal stamping processes, the material is under complex stress at the die opening, causing dislocation pile-up, which macroscopically results in work hardening and increased thickness. This leads to forming defects such as wrinkling and tearing at the die opening, ultimately affecting the uniformity of wall thickness distribution and forming quality of the part. Traditional methods such as partitioned edge pressing and initial shape optimization of the forming blank can only delay the occurrence of these defects to a certain extent. Summary of the Invention

[0005] To address the aforementioned technical problems, a forming device and method for the coordinated control of sheet metal partitioning and rapid heating are proposed. The specific technical solution is as follows:

[0006] A forming device for the coordinated control of sheet metal partitioning and rapid heating includes an upper control module, a punch, a punch insulation layer, a lower control module, a die, a die insulation layer, and a temperature measuring thermocouple.

[0007] The punch and die are respectively provided with a punch insulation layer and a die insulation layer to ensure that the punch and die are in an insulated state from the electrically powered blank during the forming process, and to prevent the pulse current from damaging the electronic components of the hydraulic press.

[0008] The upper control module includes an upper pressure head, an upper insulating layer, an upper electrode, and an upper wear-resistant auxiliary plate, which are fastened together from top to bottom by long bolts or mechanical connections.

[0009] The shape of the upper control module is artificially optimized based on the billet flow law and the shape of the flange area.

[0010] The shape of the multiple upper control modules is the same as that of the flange area, and there are gaps between each upper control module to ensure the independence of each power supply.

[0011] The lower control module includes a lower wear-resistant auxiliary plate and a lower electrode, and the shape of the lower control module corresponds to that of the upper control module.

[0012] The lower wear-resistant auxiliary plate and the lower electrode are fastened together from top to bottom using long bolts or mechanical connections.

[0013] The upper pressure head is provided with a temperature measuring hole a. The temperature measuring hole a is formed by the horizontal groove and the vertical groove being set perpendicularly. The vertical groove is a through hole that passes through the upper pressure head, the upper insulating layer, the upper electrode and the upper wear-resistant auxiliary plate. The position of the through hole is close to the chamfer of the die opening.

[0014] The temperature measuring hole b is located close to the lower surface of the die, and the temperature measuring thermocouple is inserted into the temperature measuring hole b;

[0015] The temperature measuring thermocouple directly contacts the formed slab blank and measures the temperature through the temperature measuring hole that passes through the upper pressure head, upper insulation layer, upper electrode and upper wear-resistant auxiliary plate of each group of upper control modules;

[0016] Each set of upper control modules is fastened to the hydraulic press platform by bolts and mechanical devices, and each is controlled by an independent servo control system to control the positive pressure in the vertical direction and move vertically through a guide mechanism; each set of lower control modules is mounted on the die surface by bolts or mechanical devices and fastened thereto.

[0017] Both the punch and the die are fixedly connected to the upper and lower platforms of the hydraulic press through T-slots and clamping mechanisms, ensuring the direction of movement of the punch and the die.

[0018] The upper electrode of each upper control module and the lower electrode of the corresponding lower control module are connected to an independent power supply through a conductor to form a circuit. The upper electrode in the upper control module is the positive electrode, and the lower electrode in the lower control module is the negative electrode.

[0019] In a preferred embodiment of the forming device for the coordinated control of sheet metal partitioning and rapid heating, both the punch insulation layer and the die insulation layer are surface-treated with insulating ceramics or other insulating and heat-insulating materials.

[0020] The preferred embodiment of the forming device for the coordinated control of plate partitioning edge pressing and rapid heating is as follows: the upper pressing head is made of rigid material; the upper and lower electrodes are made of low-resistance metal materials; and the upper and lower wear-resistant auxiliary plates are both made of metal materials with good wear resistance and low resistivity.

[0021] A forming method using a forming device that coordinates and controls zoned edge pressing and rapid heating of sheet metal comprises the following steps:

[0022] Step 1: Based on the specific shape of the formed part, the optimal initial blank shape and size of the formed part are obtained through finite element analysis using the methods of mapping back-reasoning and back-pressure flattening.

[0023] Step 2: Using laser cutting, wire cutting, or water jet cutting methods, process the metal blank according to the optimal initial blank shape and size, and grind the edges of the metal blank to remove burrs and flash;

[0024] Step 3: Apply an insulating and heat-insulating coating to the surfaces of the punch, die, and pressure ring. By adjusting the processing parameters, the insulating and heat-insulating coating is evenly distributed and the thickness of each part is similar to ensure the forming accuracy of the parts.

[0025] Step 4: Install the punch and die on the upper and lower platforms of the hydraulic press respectively, ensuring that the punch and die are aligned at the center position, and fix them with the T-slots and fastening bolts of the upper and lower platforms of the hydraulic press, so that the punch can move up and down with the movement of the upper platform of the hydraulic press to provide the forming force required for the deformation of the blank;

[0026] Step 5: Assemble the upper and lower control modules in sequence, using mechanical connections between each part, and ensuring insulation and heat insulation requirements. After assembly, install them in their respective positions, ensuring that there is a certain gap between each set of upper and lower control modules and the adjacent upper and lower control modules during installation, to ensure the independence of each set of control modules.

[0027] Step 6: Connect the independent forming power supply to the corresponding upper and lower electrodes, with the upper electrode connected to the positive terminal of the power supply and the lower electrode connected to the negative terminal of the power supply, ensuring that the current of each power supply can form a loop. Ensure that the power supply is turned off during installation.

[0028] Step 7: Place the shaped blank with optimized shape and size on the die and apply graphite lubricant evenly to its surface;

[0029] Step 8: Start the servo pressure control system. Based on the forming process parameters from the finite element analysis, control each upper control module to move downwards and apply initial blank holder force to the metal billet according to the regional modules to prevent wrinkling and instability of the metal billet during the forming process.

[0030] Step 9: Turn on the power supply. Based on the forming process parameters of the finite element analysis, gradually increase the current value of each power supply. The value range is 0 to 20000A. Control the deformation temperature of the metal slab in different areas by adjusting the current value. The temperature control range is 300℃ to 9000℃.

[0031] Step 10: Start the hydraulic press and slowly lower the punch to cause plastic deformation of the billet. The blank holder force and forming temperature of the metal billet in different deformation areas are controlled by the servo pressure control system and power supply current, thereby controlling the flow behavior of the material until the billet is completely attached to the mold.

[0032] Step 11: After the mold is attached, keep it warm and pressurized for 2 to 5 minutes. Then reduce the power supply current until it is zero, turn off the power, unload the vertical pressure of the upper control module, lift the punch and each upper control module, and take out the formed part.

[0033] The beneficial effects of this invention are:

[0034] This invention utilizes the Joule heating effect generated when a pulsed current passes through a metal, and employs electrodes integrated within a partitioned blank-pressing device to achieve rapid heating and temperature control of the forming blank in different regions. This allows for the design of the partitioned blank-pressing device's shape and size based on the specific shape characteristics of the part. Furthermore, it enables coordinated control of the blank-pressing force and forming temperature in different zones of the blank during forming, reducing work hardening and improving material flowability, thereby achieving high-quality forming of complex-shaped thin-walled components. The comprehensive utilization of the rapid heating and high plastic deformation capabilities of the metal blank slab assisted by current, along with the design concept and tooling structure featuring independent partitioned blank-pressing force and forming temperature control, makes this patent inventive and novel in the field of high-quality, precise forming of thin-walled metal components.

[0035] 1. It enables rapid heating of the undeformed area of ​​the flange in complex-shaped plates. Based on the deformation and flow law of the slab material, the temperature change of the undeformed area of ​​the flange during the forming process can be independently controlled in different areas, thereby achieving the regulation of material flow stress.

[0036] 2. Based on the independent temperature control of the slab in different areas, it can also be coordinated with the control of the blank holder force in different areas to achieve precise control of material flow when forming complex thin-walled parts from metal slabs, which can effectively improve the uniformity of wall thickness distribution of the formed parts. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the forming device;

[0038] Figure 2 This is a schematic cross-sectional view of the forming device in the initial stage of forming;

[0039] Figure 3 yes Figure 2 The cross-sectional view of the middle section AA - the shape of the upper control module is artificially optimized based on the billet flow law and the shape of the flange area;

[0040] Figure 4 This is a cross-sectional schematic diagram of the forming device during the forming process;

[0041] Figure 5 This is a schematic cross-sectional view of the forming device in the later stage of forming.

[0042] In the figure: 1. Temperature measuring hole a, 2. Upper pressure head, 3. Upper insulating layer, 4. Upper electrode, 5. Upper wear-resistant auxiliary plate, 6. Forming blank, 7. Punch, 8. Punch insulating layer, 9. Lower electrode, 10. Lower wear-resistant auxiliary plate, 11. Die insulating layer, 12. Die, 13. Temperature measuring hole b. Detailed Implementation

[0043] The following is in conjunction with the appendix Figure 1-5 The present invention will be further described in detail with reference to the embodiments.

[0044] Example 1

[0045] A forming device for the coordinated control of sheet metal partitioning and rapid heating includes an upper control module, a punch 7, a punch insulating layer 8, a lower control module, a die 12, and a die insulating layer 11.

[0046] The punch 7 and the die 12 are respectively provided with a punch insulation layer 8 and a die insulation layer 11 on their surfaces, which are used to ensure that the punch 7 and the die 12 are in an insulating state with the energized blank during the forming process, and to prevent the pulse current from damaging the electronic components of the hydraulic press.

[0047] The upper control module includes an upper pressure head 2, an upper insulating layer 3, an upper electrode 4, and an upper wear-resistant auxiliary plate 5, which are fastened together from top to bottom by long bolts or mechanical connections.

[0048] The shape of the upper control module is artificially optimized based on the billet flow law and the shape of the flange area.

[0049] like Figure 3 As shown, the shape formed by assembling the upper control modules a, b, c, d, e, f, g, and h is the same as the shape of the flange area, and there are gaps between each upper control module to ensure the independence of each power supply.

[0050] The lower control module includes a lower wear-resistant auxiliary plate 10 and a lower electrode 9, and the shape of the lower control module corresponds to that of the upper control module.

[0051] The lower wear-resistant auxiliary plate 10 and the lower electrode 9 are fastened together from top to bottom using long bolts or mechanical connections.

[0052] The upper pressure head 2 is provided with a temperature measuring hole a1. The temperature measuring hole a1 is formed by the horizontal groove and the vertical groove being set perpendicularly. The vertical groove is a through hole that passes through the upper pressure head 2, the upper insulating layer 3, the upper electrode 4 and the upper wear-resistant auxiliary plate 5. The position of the through hole is close to the chamfer of the die opening.

[0053] The temperature measuring hole b13 is located close to the lower surface of the die cavity, and the temperature measuring thermocouple is inserted into the temperature measuring hole b13;

[0054] The temperature measuring thermocouple directly contacts the formed blank and measures the temperature through the temperature measuring hole that passes through the upper pressure head 2, upper insulation layer 3, upper electrode 4 and upper wear-resistant auxiliary plate 5 of each group of upper control modules.

[0055] Each set of upper control modules is fastened to the hydraulic press platform by bolts and mechanical devices, and each is controlled by an independent servo control system to control the positive pressure in the vertical direction and move vertically through the guide mechanism; each set of lower control modules is mounted on the surface of the die 12 by bolts or mechanical devices and fastened.

[0056] Both the punch 7 and the die 12 are fixedly connected to the upper and lower platforms of the hydraulic press through T-slots and clamping mechanisms, ensuring the movement direction of the punch 7 and the die 12.

[0057] The upper electrode 4 of each upper control module and the lower electrode 9 of the corresponding lower control module are connected to an independent power supply through a conductor to form a circuit. The upper electrode 4 in the upper control module is the positive electrode, and the lower electrode 9 in the lower control module is the negative electrode.

[0058] Both the punch insulation layer 8 and the die insulation layer 11 are surface-treated with insulating ceramics or other insulating and heat-insulating materials.

[0059] The upper pressure head 2 is made of rigid material; the upper electrode 4 and the lower electrode 9 are made of low-resistance metal materials; and the upper wear-resistant auxiliary plate 5 and the lower wear-resistant auxiliary plate 10 are both made of metal materials with good wear resistance and low resistivity.

[0060] A forming method using a forming device that coordinates and controls zoned edge pressing and rapid heating of sheet metal comprises the following steps:

[0061] Step 1: Based on the specific shape of the formed part, the optimal initial blank shape and size of the formed part are obtained through finite element analysis using the methods of mapping back-reasoning and back-pressure flattening.

[0062] Step 2: Using laser cutting, wire cutting, or water jet cutting methods, process the metal blank according to the optimal initial blank shape and size, and grind the edges of the metal blank to remove burrs and flash;

[0063] Step 3: Apply an insulating and heat-insulating coating to the surfaces of the punch, die, and pressure ring. By adjusting the processing parameters, the insulating and heat-insulating coating is evenly distributed and the thickness of each part is similar to ensure the forming accuracy of the parts.

[0064] Step 4: Install the punch and die on the upper and lower platforms of the hydraulic press respectively, ensuring that the punch and die are aligned at the center position, and fix them with the T-slots and fastening bolts of the upper and lower platforms of the hydraulic press, so that the punch can move up and down with the movement of the upper platform of the hydraulic press to provide the forming force required for the deformation of the blank;

[0065] Step 5: Assemble the upper and lower control modules in sequence, using mechanical connections between each part, and ensuring insulation and heat insulation requirements. After assembly, install them in their respective positions, ensuring that there is a certain gap between each set of upper and lower control modules and the adjacent upper and lower control modules during installation, to ensure the independence of each set of control modules.

[0066] Step 6: Connect the independent forming power supply to the corresponding upper and lower electrodes, with the upper electrode connected to the positive terminal of the power supply and the lower electrode connected to the negative terminal of the power supply, ensuring that the current of each power supply can form a loop. Ensure that the power supply is turned off during installation.

[0067] Step 7: Place the shaped blank with optimized shape and size on the die and apply graphite lubricant evenly to its surface;

[0068] Step 8: Start the servo pressure control system. Based on the forming process parameters from the finite element analysis, control each upper control module to move downwards and apply initial blank holder force to the metal billet according to the regional modules to prevent wrinkling and instability of the metal billet during the forming process.

[0069] Step 9: Turn on the power supply. Based on the forming process parameters of the finite element analysis, gradually increase the current value of each power supply. The value range is 0 to 20000A. Control the deformation temperature of the metal slab in different areas by adjusting the current value. The temperature control range is 3000 to 9000.

[0070] Step 10: Start the hydraulic press and slowly lower the punch to cause plastic deformation of the billet. The blank holder force and forming temperature of the metal billet in different deformation areas are controlled by the servo pressure control system and power supply current, thereby controlling the flow behavior of the material until the billet is completely attached to the mold.

[0071] Step 11: After the mold is attached, keep it warm and pressurized for 2 to 5 minutes. Then reduce the power supply current until it is zero, turn off the power, unload the vertical pressure of the upper control module, lift the punch and each upper control module, and take out the formed part.

Claims

1. A forming device for the coordinated control of sheet metal partitioning and rapid heating, characterized in that: It includes an upper control module, a punch, a punch insulation layer, a lower control module, a die, a die insulation layer, and a temperature measuring thermocouple; The punch and die are respectively provided with a punch insulation layer and a die insulation layer to ensure that the punch and die are in an insulated state from the electrically powered blank during the forming process, and to prevent the pulse current from damaging the electronic components of the hydraulic press. The upper control module includes an upper pressure head, an upper insulating layer, an upper electrode, and an upper wear-resistant auxiliary plate, which are fastened together from top to bottom by long bolts or mechanical connections. The shape of the upper control module is artificially optimized based on the billet flow law and the shape of the flange area. The shape of the multiple upper control modules is the same as that of the flange area, and there are gaps between each upper control module to ensure the independence of each power supply. The lower control module includes a lower wear-resistant auxiliary plate and a lower electrode, and the shape of the lower control module corresponds to that of the upper control module. The lower wear-resistant auxiliary plate and the lower electrode are fastened together from top to bottom using long bolts or mechanical connections. The upper pressure head is provided with a temperature measuring hole a. The temperature measuring hole a is formed by the horizontal groove and the vertical groove being set perpendicularly. The vertical groove is a through hole that passes through the upper pressure head, the upper insulating layer, the upper electrode and the upper wear-resistant auxiliary plate. The position of the through hole is close to the chamfer of the die opening. The temperature measuring hole b is located close to the lower surface of the die, and the temperature measuring thermocouple is inserted into the temperature measuring hole b; The temperature measuring thermocouple directly contacts the formed slab blank and measures the temperature through the temperature measuring hole that passes through the upper pressure head, upper insulation layer, upper electrode and upper wear-resistant auxiliary plate of each group of upper control modules; Each set of upper control modules is fastened to the hydraulic press platform by bolts and mechanical devices, and each is controlled by an independent servo control system to control the positive pressure in the vertical direction and move vertically through a guide mechanism; each set of lower control modules is mounted on the die surface by bolts or mechanical devices and fastened thereto. Both the punch and the die are fixedly connected to the upper and lower platforms of the hydraulic press through T-slots and clamping mechanisms, ensuring the direction of movement of the punch and the die. The upper electrode of each upper control module and the lower electrode of the corresponding lower control module are connected to an independent power supply through a conductor to form a circuit. The upper electrode in the upper control module is the positive electrode, and the lower electrode in the lower control module is the negative electrode.

2. The forming device for the coordinated control of sheet metal partitioning and rapid heating according to claim 1, characterized in that: Both the punch insulation layer and the die insulation layer are surface-treated with insulating ceramics or other insulating and heat-insulating materials.

3. The forming device for the coordinated control of sheet metal partitioning and rapid heating according to claim 1, characterized in that: The upper pressure head is made of a rigid material; the upper and lower electrodes are made of low-resistance metal materials; and the upper and lower wear-resistant auxiliary plates are both made of metal materials with good wear resistance and low resistivity.

4. The forming method of the forming device for the coordinated control of sheet metal partitioning and rapid heating according to claim 1, characterized in that: The following steps are required: Step 1: Based on the specific shape of the formed part, the optimal initial blank shape and size of the formed part are obtained through finite element analysis using the methods of mapping back-reasoning and back-pressure flattening. Step 2: Using laser cutting, wire cutting, or water jet cutting methods, process the metal blank according to the optimal initial blank shape and size, and grind the edges of the metal blank to remove burrs and flash; Step 3: Apply an insulating and heat-insulating coating to the surfaces of the punch, die, and pressure ring. By adjusting the processing parameters, the insulating and heat-insulating coating is evenly distributed and the thickness of each part is similar to ensure the forming accuracy of the parts. Step 4: Install the punch and die on the upper and lower platforms of the hydraulic press respectively, ensuring that the punch and die are aligned at the center position, and fix them with the T-slots and fastening bolts of the upper and lower platforms of the hydraulic press, so that the punch can move up and down with the movement of the upper platform of the hydraulic press to provide the forming force required for the deformation of the blank; Step 5: Assemble the upper and lower control modules in sequence, using mechanical connections between each part, and ensuring insulation and heat insulation requirements. After assembly, install them in their respective positions, ensuring that there is a certain gap between each set of upper and lower control modules and the adjacent upper and lower control modules during installation, to ensure the independence of each set of control modules. Step 6: Connect the independent forming power supply to the corresponding upper and lower electrodes, with the upper electrode connected to the positive terminal of the power supply and the lower electrode connected to the negative terminal of the power supply, ensuring that the current of each power supply can form a loop. Ensure that the power supply is turned off during installation. Step 7: Place the shaped blank with optimized shape and size on the die and apply graphite lubricant evenly to its surface; Step 8: Start the servo pressure control system. Based on the forming process parameters from the finite element analysis, control each upper control module to move downwards and apply initial blank holder force to the metal billet according to the regional modules to prevent wrinkling and instability of the metal billet during the forming process. Step 9: Turn on the power supply. Based on the forming process parameters of the finite element analysis, gradually increase the current value of each power supply. The value range is 0 to 20000A. Control the deformation temperature of the metal slab in different areas by adjusting the current value. The temperature control range is 300℃ to 900℃. Step 10: Start the hydraulic press and slowly lower the punch to cause plastic deformation of the billet. The blank holder force and forming temperature of the metal billet in different deformation areas are controlled by the servo pressure control system and power supply current, thereby controlling the flow behavior of the material until the billet is completely attached to the mold. Step 11: After the mold is attached, keep it warm and pressurized for 2 to 5 minutes. Then reduce the power supply current until it is zero, turn off the power, unload the vertical pressure of the upper control module, lift the punch and each upper control module, and take out the formed part.

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