Device and method for inhibiting failure of stamping interface of plated plate through pulse current regulation and control

Abstract

The invention provides a device and method for restraining plate stamping interface failure through pulse current regulation and control, and the system comprises a plate stamping module which is used for carrying out the stamping forming of a plate; the plurality of electrode clamps are detachably connected with the plate respectively, and electrodes are arranged on the electrode clamps; the current box is electrically connected with the electrode; the thermocouple is electrically connected with the current box and is used for acquiring temperature data of the plate; the ultrasonic emission sensor is electrically connected with the current box and is used for acquiring ultrasonic signal intensity data; the current box is configured to apply a heating current to the plated plate according to the temperature data, apply a preset high-strength low-frequency current to the plated plate after the temperature data reaches a target temperature, apply a low-strength high-frequency current to the plated plate when the ultrasonic signal strength reaches a preset strength in the punch forming process, continuously increase the density of the low-strength high-frequency current, and perform punch forming on the plated plate; the ultrasonic signal intensity is not increased any more. Therefore, the forming performance can be improved by introducing the high-strength low-frequency composite low-strength high-frequency pulse current.

Description

Technical Field

[0001] This invention relates to the field of coated sheet production technology, and in particular to a device and method for suppressing the failure of the stamping interface of coated sheets by pulse current regulation. Background Technology

[0002] To improve the corrosion resistance and conductivity of ultra-thin titanium alloy bipolar plates, an electroplating nickel coating process is required after stamping. However, due to poor deep plating and uniform plating capabilities during electroplating, incomplete plating can easily occur in the microchannel structure of the bipolar plate, making it difficult to guarantee the required service life of the bipolar plate.

[0003] In related technologies, by advancing the plating process, nickel plating is performed on the surface of an ultra-thin titanium substrate using electroplating before stamping, allowing the formed parts to be directly put into service. However, during the stamping process of ultra-thin nickel-plated titanium alloy sheets, the size effect exacerbates the uneven elastic-plastic deformation between the nickel plating and the titanium substrate, which can easily lead to interface delamination defects between the substrate and the plating after the ultra-thin nickel-plated titanium sheet is stamped. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the above-mentioned technologies.

[0005] Therefore, the purpose of this invention is to propose a device and method for suppressing the failure of the stamping interface of coated sheet material by pulse current regulation. By introducing a high-intensity low-frequency composite low-intensity high-frequency pulse current, the rheological stress of the material is reduced, the ductility is improved, and the microstructure evolution is accelerated, thereby improving the forming performance.

[0006] To achieve the above objectives, a first aspect of the present invention provides a pulse current-regulated device for suppressing interface failure of coated sheet metal during stamping, comprising: a sheet metal stamping module for stamping coated sheet metal; multiple electrode clamps detachably connected to the coated sheet metal, each electrode clamp having an electrode disposed thereon; a current box electrically connected to the electrodes; a thermocouple electrically connected to the current box for acquiring temperature data of the coated sheet metal; and an ultrasonic emission sensor electrically connected to the current box for acquiring ultrasonic signal intensity data. The current box is configured to apply a heating current to the coated sheet metal according to the temperature data; when the temperature data reaches a target temperature, a preset high-intensity low-frequency current is applied to the coated sheet metal; during the stamping process, when the ultrasonic signal intensity exceeds the preset intensity, a low-intensity high-frequency current is applied to the coated sheet metal, continuously increasing the low-intensity high-frequency current density until the ultrasonic signal intensity no longer increases.

[0007] In one embodiment of the present invention, the thermocouple and the ultrasonic emission sensor are respectively aligned with the substrate / coating interface of the coated sheet.

[0008] In one embodiment of the present invention, the sheet metal stamping module includes: a pressure servo machine, an upper die base, an upper die, a lower die base, a lower die, and a guide member. The upper die is disposed on the upper die base, the lower die is disposed on the lower die base, the upper die base and the lower die base are connected by the guide member, and the pressure servo machine is disposed above the upper die base.

[0009] In one embodiment of the present invention, insulating pads are respectively provided between the upper mold base and the pressure servo machine, and between the lower mold base and the lower mold. The insulating pads are used to isolate current to prevent current from interfering with the sheet metal stamping module.

[0010] In one embodiment of the present invention, it further includes: an edge pressing device, which is disposed on the guide and is detachably connected to the plated sheet. The edge pressing device is used to clamp both ends of the plated sheet to correct the position of the plated sheet.

[0011] In one embodiment of the present invention, the device further includes an oscilloscope, which is electrically connected to the sheet metal stamping module, the current box, the thermocouple, and the ultrasonic emission sensor, respectively. The oscilloscope is configured to generate a force-displacement curve based on the stamping stroke and stamping force data of the sheet metal stamping module, an ultrasonic signal intensity-time curve based on the ultrasonic signal intensity data of the ultrasonic emission sensor, a sheet metal temperature-time curve based on the temperature data of the thermocouple, and a current density-time curve based on the current data of the current box.

[0012] A second aspect of the present invention provides a method for suppressing the failure of the stamping interface of a coated sheet material by pulse current regulation, comprising: clamping an electrode fixture onto the coated sheet material; arranging an ultrasonic emission sensor and a thermocouple at the coating / substrate interface of the coated sheet material; supplying a heating current to the coated sheet material through the electrode fixture via a current box; applying a preset high-intensity low-frequency current to the coated sheet material after the thermocouple detects that the temperature of the coated sheet material has reached the forming temperature; stamping the coated sheet material through a sheet stamping module; when the ultrasonic signal intensity acquired by the ultrasonic emission sensor reaches a preset intensity, applying a low-intensity high-frequency current to the coated sheet material via the current box, continuously increasing the low-intensity high-frequency current density until the ultrasonic signal intensity no longer increases; and obtaining the formed coated sheet material after the stamping process is completed.

[0013] In one embodiment of the present invention, the preset intensity of the ultrasonic signal is lower than the critical intensity of the ultrasonic signal when the stamping interface of the coated sheet fails.

[0014] The beneficial effects of this invention are: The current box applies heating current and composite pulse current to the coated sheet through electrode clamps. The heating current can quickly heat the coated sheet to the forming temperature, improving forming efficiency. Since titanium and nickel alloys have different sensitivities to current parameters, the loading parameters of the composite pulse current (high-intensity low-frequency composite low-intensity high-frequency pulse current) are optimized to target and control the electroplastic effect between the substrate and the coating, thereby reducing uneven deformation between the substrate and the coating and improving the stamping performance of ultra-thin nickel-titanium plate.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a device for suppressing the failure of the stamping interface of a coated sheet material by pulse current regulation according to an embodiment of the present invention. Figure 2 This is a schematic flowchart of a method for suppressing the failure of the stamping interface of a coated sheet by pulse current modulation according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the temperature-time curve of the board material on an oscilloscope according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the ultrasonic signal intensity-time curve on an oscilloscope according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the force-displacement curve on an oscilloscope according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the current density-time curve on an oscilloscope according to an embodiment of the present invention.

[0017] As shown in the figure: 1. Sheet metal stamping module, 11. Pressure servo motor, 12. Upper die holder, 13. Upper die, 14. Lower die holder, 15. Lower die, 16. Guide component, 2. Electrode clamp, 3. Electrode, 4. Current box, 5. Thermocouple, 6. Ultrasonic emission sensor, 7. Insulating pad, 8. Edge pressing device, 9. Oscilloscope. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] The following describes, with reference to the accompanying drawings, an embodiment of the present invention: a device and method for suppressing the failure of the stamping interface of coated sheet metal by pulse current regulation.

[0020] The pulse current modulation device for suppressing interface failure of coated sheet metal during stamping according to embodiments of the present invention, such as... Figure 1 As shown, it may include: sheet metal stamping module 1, multiple electrode clamps 2, current box 4, thermocouple 5, and ultrasonic emission sensor 6.

[0021] The sheet metal stamping module 1 is used to stamp and form the coated sheet metal. Multiple electrode clamps 2 are detachably connected to the coated sheet metal. Electrodes 3 are provided on the electrode clamps 2. The current box 4 is electrically connected to the electrode 3. Thermocouple 5 is electrically connected to the current box 4 and is used to obtain the temperature data of the coated sheet metal. Ultrasonic emission sensor 6 is electrically connected to the current box 4 and is used to obtain the ultrasonic signal intensity data.

[0022] The current box 4 is configured to apply a heating current to the coating material according to the temperature data. When the temperature data reaches the target temperature, a preset high-intensity low-frequency current is applied to the coating material. During the stamping process, when the ultrasonic signal intensity exceeds the preset intensity, a low-intensity high-frequency current is applied to the coating material, and the low-intensity high-frequency current density is continuously increased until the ultrasonic signal intensity no longer increases.

[0023] It should be noted that titanium alloy (substrate) and nickel plating exhibit fundamentally different responses under pulsed current.

[0024] Titanium substrates have high resistivity and low thermal conductivity, making them more prone to local instantaneous temperature rise and temperature gradients under the same current density. This allows low-intensity, high-frequency currents to rapidly activate dislocations locally, resulting in significant electro-softening.

[0025] Nickel plating is more sensitive to continuous high-intensity low-frequency current. Under this disturbance, it can continuously activate dislocation movement, promote dynamic recovery, reduce overall hardening accumulation and protect the integrity of the plating, thereby reducing flow stress during critical deformation stages.

[0026] Furthermore, the ultrasonic emission sensor 6 and the thermocouple 5 are aligned with the substrate / coating interface of the coated sheet, respectively.

[0027] As one possible scenario, the electrode clamp 2 can be an eccentric wheel clamp. The electrode clamp 2 may include a clamp body and an eccentric wheel assembly. The clamping force is generated by the change in radius when the eccentric wheel rotates, so that the electrode clamp 2 can be clamped on the coated plate.

[0028] As another possibility, the electrode clamp 2 can be a screw clamp, which achieves clamping through the thread transmission principle, so that the electrode clamp 2 can be clamped on the coating plate.

[0029] It is understood that the current box 4 described in this embodiment is equipped with multiple pulse signals (e.g., a heating current channel, a high-intensity low-frequency current channel, a low-intensity high-frequency current channel, etc.). The heating current channel of the current box 4 is set up to heat the coating material. Before the coating material is stamped, the high-intensity low-frequency current channel of the current box 4 is set up to apply a preset intensity of high-intensity low-frequency current to the coating material. Based on the ultrasonic signal intensity data, the low-intensity high-frequency current channel is set up at an appropriate time to apply a low-intensity high-frequency current to the coating material.

[0030] To clearly illustrate the previous embodiment, in one embodiment of the present invention, as follows: Figure 1 As shown, the sheet metal stamping module 1 includes: a pressure servo motor 11, an upper die holder 12, an upper die 13, a lower die holder 14, a lower die 15, and a guide member 16. The upper die 13 is disposed on the upper die holder 12, and the lower die 15 is disposed on the lower die holder 14. The upper die holder 12 and the lower die holder 14 are connected by the guide member 16. The pressure servo motor 11 is disposed above the upper die holder 12.

[0031] It is understandable that the sheet metal stamping module 1 is a stamping die. The stamping force is applied by the pressure servo machine 11, and the upper die 13 and lower die 15 apply pressure to the coated sheet metal to stamp and form the coated sheet metal. Among them, the pressure servo machine 11 can obtain force-displacement data based on the stamping force and stamping stroke it applies.

[0032] Furthermore, insulating pads 7 (e.g., natural rubber, styrene-butadiene rubber, butyl rubber, etc.) are respectively provided between the upper mold base 12 and the pressure servo machine 11, and between the lower mold base 14 and the lower mold 15. The insulating pads 7 are used to isolate current to prevent current interference with the sheet metal stamping module 1.

[0033] It also includes: a pressing device 8, which is mounted on the guide member 16 and is detachably connected to the plated sheet. The pressing device 8 is used to clamp both ends of the plated sheet to correct the position of the plated sheet.

[0034] It should be noted that the blank holder 8 (e.g., rigid blank holder 8, elastic blank holder 8, etc.) is a component in the stamping die used to prevent the material at the edge of the workpiece from becoming unstable.

[0035] To facilitate the quantification of the interface delamination suppression effect during the experiment, this embodiment introduces the "suppression margin evaluation formula" as a quantification index. By fitting this index through multiple experiments and calculations, the parameters of high-intensity low-frequency current and low-intensity high-frequency current are obtained, and the sufficiency of the applied composite pulse current field in suppressing interface delamination is judged.

[0036] In the formula For margin, The larger the value, the more effective the suppression; This represents the typical size of a microcrack at the interface; This is the equivalent elastic modulus at the interface; The interfacial energy release rate under the action of electric current relative to the critical value The amount of reduction; The critical energy release rate at the interface; The flow stress of the substrate under no-current conditions; The flow stress of the coating under no-current conditions; The relative softening factor of the substrate / coating due to the electro-induced effect; For low-intensity high-frequency channels, the current density and frequency are used. For the current density and frequency of the high-intensity low-frequency channel; The phase difference between the two pulses; coefficient , , , , Determined by experimental fitting; is a dimensionless power exponent of current density, used to characterize the nonlinear sensitivity of the electrosoftening effect to changes in current amplitude. It is a dimensionless power exponent of frequency, used to characterize the enhancement or attenuation characteristics of electro-effects as frequency changes. This is a dimensionless power-law parameter used to describe the nonlinear weight of high-frequency current density on the electrosoftening / interface inhibition effect of materials under dual-channel (high-frequency–low-frequency) current coupling.

[0037] Specifically, the upper die 13 and the lower die 15 are respectively installed on the upper die base 12 and the lower die base 14. Insulating pads 7 are placed between the upper die base 12 and the upper die 13, and between the lower die base 14 and the lower die 15 to isolate the current. Then, the pressure servo motor 11 is connected to the upper die base 12. After the plated sheet is placed on the sheet metal stamping module 1, the plated sheet is clamped on the edge pressing device 8, and the position of the plated sheet is corrected by the edge pressing device 8. After clamping, the electrode clamp 2 is clamped on the plated sheet.

[0038] Connect the current box 4 to the electrode 3 with a wire and tighten it with a torque bolt. Fix the ultrasonic emission sensor 6 to the interface / coating of the coated substrate. Fix the thermocouple 5 to the interface / coating of the coated substrate.

[0039] Turn on the ultrasonic emission sensor 6, pressure servo motor 11, current box 4, and thermocouple 5. Adjust the status of each device. Perform a no-load test on the pulse current synchronous output of current box 4 (current controller), the status of pressure servo motor 11, the temperature test status of output thermocouple 5, and the interface connection status of ultrasonic emission sensor 6 to ensure that the temperature, ultrasonic, force-displacement, and current data signals are normal. Heat the coated sheet material by applying a heating current to current box 4 until it reaches a suitable forming temperature (heating forming temperature is 280℃~300℃). Then, apply a high-intensity, low-frequency current (current density JLF=60A, current frequency fLF=5Hz) to current box 4, and activate the overcurrent, short-circuit, and over-temperature protection circuits. Set the stamping speed v and stamping distance (stroke) L of pressure servo motor 11 to begin stamping.

[0040] When the ultrasonic signal intensity rises to the preset intensity, it indicates that the coating on the sheet metal is prone to peeling. A low-intensity, high-frequency current (current density JHF=6A, current frequency fHF=60kHz, phase difference ϕ=0 with the high-intensity, low-frequency current) is applied to the coated sheet metal through the current box 4. When the ultrasonic signal intensity no longer increases and does not reach the critical intensity for failure of the stamping interface of the coated sheet metal, it indicates that the delamination phenomenon of the coating interface is effectively suppressed, and the current intensity of the low-intensity, high-frequency current is maintained. After the stamping is completed, the current transmission between the current box 4 and the coated sheet metal is stopped. The coated sheet metal is allowed to cool naturally to room temperature before being removed.

[0041] like Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, it also includes: an oscilloscope 9, which is electrically connected to the sheet metal stamping module 1, the current box 4, the thermocouple 5 and the ultrasonic emission sensor 6 respectively. The oscilloscope 9 is configured to generate a force-displacement curve based on the stamping stroke and stamping force data (force-displacement signal) of the sheet metal stamping module 1, generate an ultrasonic signal intensity-time curve based on the ultrasonic signal intensity data of the ultrasonic emission sensor 6, generate a sheet metal temperature-time curve based on the temperature data of the thermocouple 5, and generate a current density-time curve based on the current data of the current box 4.

[0042] It should be noted that the pressure servo motor 11 (built-in controller), current box 4, thermocouple 5 described in the above embodiments can be connected to the oscilloscope 9 with wires, and the ultrasonic emission sensor 6 can be connected to the oscilloscope 9 with cables that are far away from the main current conductor and grounded according to the single-end grounding principle.

[0043] When the oscilloscope 9 is turned on, it can generate force-displacement curves, ultrasonic signal intensity-time curves, sheet temperature-time curves, and current density-time curves in real time throughout the stamping process, so that relevant personnel can observe the data.

[0044] like Figure 2 As shown, the method for suppressing the failure of the stamping interface of the coated sheet by pulse current modulation may include: Step 101: Clamp the electrode fixture onto the coated plate.

[0045] Step 102: An ultrasonic emission sensor and a thermocouple are installed at the coating / substrate interface of the coated sheet.

[0046] Step 103: The current box delivers heating current to the coating material through the electrode clamp. After the thermocouple detects that the temperature of the coating material has reached the forming temperature, a preset high-intensity low-frequency current is applied to the coating material.

[0047] Step 104: The coated sheet is stamped into shape using the sheet stamping module.

[0048] Step 105: When the intensity of the ultrasonic signal acquired by the ultrasonic emission sensor reaches the preset intensity, the current box applies a low-intensity high-frequency current to the coating material until the intensity of the ultrasonic signal no longer increases, and the low-intensity high-frequency current density is continuously increased.

[0049] Step 106: Stamping and forming are completed, and the formed coated sheet is obtained.

[0050] To clearly illustrate the previous embodiment, in one embodiment of the present invention, the preset intensity of the ultrasonic signal intensity is lower than the critical intensity of the ultrasonic signal intensity when the stamping interface of the coated sheet fails.

[0051] It should be noted that during the stamping process, if the ultrasonic signal intensity displayed on the oscilloscope rises to the preset intensity (the preset ultrasonic signal intensity is about 350mV), open the low-intensity high-frequency current channel and adjust its current amplitude ratio and phase ratio; observe the ultrasonic signal. If, through the application of low-intensity high-frequency current, it is found that the ultrasonic signal intensity no longer rises and the ultrasonic signal intensity has not reached the critical intensity of interface delamination failure (the critical intensity of ultrasonic signal intensity is about 400mV), it proves that the interface delamination failure phenomenon has been effectively suppressed.

[0052] In summary, the pulse current modulation device and method for suppressing the failure of the stamping interface of coated sheet material in this embodiment of the invention improves the forming performance by introducing a high-intensity low-frequency composite low-intensity high-frequency pulse current, thereby reducing the rheological stress of the material, improving its ductility, and accelerating the evolution of its microstructure.

[0053] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," and "example" refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0055] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A device for suppressing interface failure of coated sheet metal under pulse current regulation, characterized in that, include: Sheet metal stamping module, used for stamping coated sheet metal into shape; Multiple electrode clamps are detachably connected to the coating plate, and electrodes are provided on the electrode clamps; A current box is electrically connected to the electrodes; Thermocouple, electrically connected to the current box, is used to obtain temperature data of the coated sheet material; An ultrasonic emission sensor, electrically connected to the current box, is used to acquire ultrasonic signal intensity data; The thermocouple and the ultrasonic emission sensor are respectively aligned with the substrate / coating interface of the coated plate. The current box is configured to apply a heating current to the coating material according to the temperature data. When the temperature data reaches the target temperature, a preset high-intensity low-frequency current is applied to the coating material. During the stamping process, when the ultrasonic signal intensity reaches the preset intensity, a low-intensity high-frequency current is applied to the coating material, and the low-intensity high-frequency current density is continuously increased until the ultrasonic signal intensity no longer increases.

2. The pulse current modulation device for suppressing interface failure of coated sheet metal as described in claim 1, characterized in that, The sheet metal stamping module includes: a pressure servo machine, an upper die base, an upper die, a lower die base, a lower die, and a guide component. The upper die is disposed on the upper die base, and the lower die is disposed on the lower die base. The upper die base and the lower die base are connected by the guide component, and the pressure servo machine is disposed above the upper die base.

3. The device for suppressing interface failure of coated sheet metal by pulse current regulation according to claim 2, characterized in that, Insulating pads are respectively provided between the upper mold base and the pressure servo machine, and between the lower mold base and the lower mold. The insulating pads are used to isolate current to prevent current from interfering with the sheet metal stamping module.

4. The pulse current modulation device for suppressing interface failure of coated sheet metal as described in claim 2, characterized in that, Also includes: An edge-pressing device is provided on the guide member and is detachably connected to the plated sheet. The edge-pressing device is used to clamp both ends of the plated sheet to correct the position of the plated sheet.

5. The pulse current modulation device for suppressing interface failure of coated sheet metal as described in claim 1, characterized in that, Also includes: An oscilloscope is electrically connected to the sheet metal stamping module, the current box, the thermocouple, and the ultrasonic emission sensor, respectively. The oscilloscope is configured to generate a force-displacement curve based on the stamping stroke and stamping force data of the sheet metal stamping module, an ultrasonic signal intensity-time curve based on the ultrasonic signal intensity data of the ultrasonic emission sensor, a sheet metal temperature-time curve based on the temperature data of the thermocouple, and a current density-time curve based on the current data of the current box.

6. A method for suppressing stamping interface failure of coated sheet metal by pulse current regulation, based on the pulse current regulation device for suppressing stamping interface failure of coated sheet metal according to any one of claims 1-5, characterized in that, include: The electrode clamp is attached to the coated plate. An ultrasonic emission sensor and a thermocouple are placed at the interface between the coating and the substrate of the coated sheet. The current box delivers heating current to the coating material through the electrode clamp. After the thermocouple detects that the temperature of the coating material has reached the forming temperature, a preset high-intensity low-frequency current is applied to the coating material. The coated sheet is stamped into shape using a sheet metal stamping module. When the intensity of the ultrasonic signal acquired by the ultrasonic transmitting sensor reaches the preset intensity, the current box applies a low-intensity high-frequency current to the coating material and continuously increases the density of the low-intensity high-frequency current until the ultrasonic signal intensity no longer increases. After the stamping process is completed, the coated sheet material is obtained.

7. The method for suppressing stamping interface failure of coated sheet metal by pulse current modulation according to claim 6, characterized in that, The preset intensity of the ultrasonic signal should be lower than the critical intensity of the ultrasonic signal when the stamping interface of the coated sheet fails due to delamination.

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