A helical wire anode rotating disc apparatus for electroforming additive manufacturing

Abstract

The application discloses a spiral wire anode rotating disc device for electroforming additive manufacturing, and belongs to the technical field of electroforming additive manufacturing. The device comprises a rotating disc carrier plate, a plurality of wire anodes, an auxiliary cathode and a power supply. The lower surface of the rotating disc carrier plate is provided with Archimedes type arranged spiral grooves, and is staggered with the wire anodes to form a driving type micro channel system; the auxiliary cathode is arranged at the outer side edge of the rotating disc and is connected with the power supply through a shunt. The application improves the current carrying capacity and effective working area through the parallel arrangement of the multiple anodes, enhances the inter-electrode mass transfer efficiency in combination with the micro channel system, and suppresses the edge effect by using the auxiliary cathode. The synergistic work of the structure optimizes the electric field distribution and the mass transfer process, thereby realizing the synchronous improvement of the deposition rate, thickness uniformity and effective utilization rate of the substrate, and can be widely applied to the additive manufacturing scene of the metal microstructure with high efficiency and high consistency.

Description

Technical Field

[0001] This invention relates to the field of electroforming technology, and more specifically to a spiral anode rotating disk device for electroforming additive manufacturing. Background Technology

[0002] Electroforming is a key technology for directly forming metal microstructures based on electrochemical deposition, and it has wide applications in high-end manufacturing fields such as semiconductor chip wafer-level interconnects, microelectrode arrays, microelectromechanical systems (MEMS), precision optics, and biomedical devices. As related fields develop towards smaller feature sizes, higher integration, and mass production, more comprehensive and stringent requirements are being placed on the deposition efficiency, surface uniformity, and large-scale fabrication capabilities of electroforming technology.

[0003] Compared to traditional electroforming processes, the emerging line-anode scanning electroforming technology exhibits significant advantages, particularly in the fabrication of high-purity, high-strength, and high-resolution nano / micron-scale metal structures. Against this backdrop, motion-scanning line-anode electroforming technology, which dynamically covers the entire deposition area by planning the ordered movement path of the anode, is considered a potentially advantageous solution for simultaneously optimizing the interelectrode electric field distribution and the electrolyte mass transfer field, thereby achieving large-area, highly uniform deposition.

[0004] Among the various traditional line anode layouts mentioned in the academic paper (Zhang Yasai. Research on linear anode-to-cathode rotary scanning electrodeposition technology [D]. Henan Polytechnic University, 2024.DOI:10.27116 / d.cnki.gjzgc.2024.000307.), the radial line anode arrangement is quite representative. Compared with the traditional reciprocating linear scanning line anode structure, this method optimizes the electric field uniformity to a certain extent and improves the thickness consistency of the electroformed layer, but it also has obvious limitations: (1) the radial line anode is prone to electric field line superposition in the central area of ​​the disk, forming a current density concentration area; (2) under constant rotation speed, the linear velocity of each point of the anode changes linearly with the radial position, resulting in different effective action time in different radius areas, which in turn causes uneven distribution of metal deposition thickness. Therefore, although this structure can be applied to occasions where uniformity requirements are not high, it is still insufficient in electroforming applications with high precision and high uniformity requirements.

[0005] The invention patent application number 202511678364.X proposes a rotating scanning electroforming device based on an Archimedes spiral anode. This scheme effectively improves the uniform coverage of the electric field in the entire deposition area and promotes the ion mass transfer effect on a macroscopic scale by using a unique Archimedes spiral anode arrangement combined with a synergistic mechanism of central liquid supply and cathode rotation. However, there is still considerable room for optimization in this scheme: (1) Due to the limited energy carrying capacity (current / voltage) of a single spiral micro-wire anode, it is difficult to obtain a high average energy density (current density) across the entire cathode area, resulting in a small maximum deposition rate and low production efficiency; (2) The mass transfer process of this device mainly relies on the shear flow generated by the rotation of the cathode plane. The average velocity of the shear flow generated by the flat surface is low and the flow layer is thin. It is difficult to achieve rapid transport and renewal of materials in the narrow processing gap (<1mm). More seriously, due to the effect of the radial linear velocity gradient change of the rotating disk, the shear flow field in the processing gap has inherent uneven distribution; (3) During the electroforming process, the edge of the cathode substrate will cause the electric field lines to concentrate due to its geometry. At the same time, the stray electric field generated by the wire anode in this area further leads to uneven electric field distribution, thus forming a significant "edge effect". This effect will cause the local current density at the edge of the cathode substrate to be high, resulting in a reduction in the effective usable area of ​​the uniform electric field distribution on the surface of the disc cathode substrate, a reduction in material utilization, and an increase in manufacturing costs. Summary of the Invention

[0006] This invention provides a spiral anode rotary disk device for electroforming additive manufacturing, aiming to systematically overcome the shortcomings of existing electroforming additive manufacturing technology based on the rotational motion of the linear anode, and solve problems such as insufficient and uneven electrolyte mass transfer, low deposition efficiency, uneven electric field distribution and prominent cathode edge effect, so as to provide a tool carrier for implementing electroforming additive manufacturing with higher quality and higher efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A spiral anode rotating disk device for electroforming additive manufacturing includes a rotating disk carrier plate, a wire anode, an auxiliary cathode, a power supply, a cathode substrate shunt, and an auxiliary cathode shunt. The lower surface of the rotating disk carrier plate has spiral grooves. The wire anode is mounted on the lower surface of the rotating disk carrier plate. An even number of spiral grooves are arranged parallel to the even number of wire anodes, following the trajectory of an Archimedean spiral and interleaved. A liquid supply hole for injecting electrolyte is located at the center of the rotating disk carrier plate. The inlet of each spiral groove communicates with the liquid supply hole, and the outlet is located at the outermost edge of the lower surface of the rotating disk carrier plate. The auxiliary cathode is mounted on the side of the rotating disk carrier plate. The anode of the power supply is electrically connected to the wire anode, and the negative terminal of the power supply is electrically connected to the cathode substrate and the auxiliary cathode through the cathode substrate shunt and the auxiliary cathode shunt, respectively. The rotating disk carrier plate is positioned parallel and directly above the cathode substrate. The rotating disk carrier plate rotates in the same direction as the Archimedean spiral and its rotation speed is adjustable.

[0009] Preferably, the trajectory of the Archimedean spiral is derived from the polar coordinate equation. Definition, where Let be the initial radius, in mm; The pitch factor is mm / rad; Polar angle, radians ; The extreme diameter is in mm.

[0010] Preferably, the spiral groove has an initial radius different from that of the wire anode. and polar angle The spiral grooves are arranged alternately with the linear anodes; the depth of the spiral grooves is 0.1~0.3mm and the width is 0.3~0.5mm.

[0011] Preferably, the wire anode is made of platinum with a purity of not less than 99.999% and has a width of 0.05mm to 0.1mm.

[0012] Preferably, the rotating disk carrier plate is slidably disposed in the vertical direction.

[0013] Preferably, the distance between the rotating disk carrier plate and the cathode substrate is adjustable within the range of 0.1 mm to 1 mm.

[0014] Preferably, the auxiliary cathode is embedded in the side of the rotating disk carrier plate, and its outer surface is flush with the side of the rotating disk carrier plate.

[0015] Preferably, the linear anode is embedded in the lower surface of the rotating disk carrier plate, and its lower surface is flush with the lower surface of the rotating disk carrier plate.

[0016] Preferably, the rotational speed of the rotating disk carrier plate is adjustable within the range of 0.5~16 r / s.

[0017] Preferably, the rotating disk carrier plate is made of an electrically insulating material that is resistant to acid and alkali corrosion.

[0018] Compared with the prior art, the present invention has the following significant features and advantages:

[0019] (1) Significantly improves deposition rate and production efficiency. By expanding a single wire anode into an even number of parallel arranged wires, the effective working area of ​​the electrode and the current carrying capacity of the system are significantly increased, resulting in a multiple increase in the average current density that can be applied to the cathode substrate surface. At the same time, the spiral grooves arranged interlaced with the wire anodes, in conjunction with the rotation of the rotating disk carrier plate, constitute an active microchannel system, which greatly enhances the directional flow effect of the electrolyte between electrodes and the ion mass transfer efficiency, enabling rapid ion replenishment and effectively suppressing concentration polarization. The synergistic effect of the electric field and mass transfer ensures that the cathode substrate can achieve continuous and stable high-speed deposition under higher current density conditions, thereby significantly improving the overall deposition rate and production efficiency.

[0020] (2) The uniformity of thickness / size distribution of electroformed parts is significantly improved. In terms of electric field, the uniform arrangement of multiple linear anodes combined with the independent control of the outer auxiliary cathode effectively suppresses the phenomenon of current density concentration in the edge region, making the electric field distribution more balanced in the radial direction. At the same time, the spiral groove guides the spiral flow of the electrolyte, which significantly enhances the radial transport, replenishment and exchange capacity of ions from the center to the edge, effectively reduces the concentration gradient in the processing gap, and further optimizes the ion mass transfer effect. The synergistic effect of electric field uniformity and enhanced ion mass transfer ensures that the thickness of the metal deposition layer is highly consistent from the center to the edge.

[0021] (3) The effective usable area and the proportion of effective products have been further increased. The microfluidic system effectively improves the problem of insufficient ion supply caused by mass transfer lag in the surrounding area by continuously replenishing reactive ions, promotes a more uniform ion distribution on the cathode substrate surface, thereby expanding the effective working area that can achieve high-quality deposition, improving the utilization rate of cathode substrate materials, and enhancing the economy of the overall manufacturing process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the spiral anode rotating disk device of the present invention;

[0023] Figure 2 This is a cross-sectional view of the linear anode structure of the device of the present invention;

[0024] Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle;

[0025] Figure 4 This is a bottom view of the line anode structure of the device of the present invention;

[0026] Figure 5 This is a schematic diagram of the cathode working device of the present invention;

[0027] Figure 6 This is a schematic diagram illustrating the operation of an embodiment of the device of the present invention.

[0028] The labels and names in the diagram are as follows: 1. Inlet channel; 2. Rotating shaft; 3. Rotating disk carrier plate; 4. Metal deposition layer; 5. Cathode mask; 6. Cathode substrate; 7. Cathode carrier plate; 8. Outlet; 9. Cathode substrate distributor; 10. Auxiliary cathode distributor; 11. Power supply; 12. Auxiliary cathode; 13. Spiral groove; 14. Wire anode; 15. Liquid supply hole; 16. Inlet; 17. Electrolyte; 18. Electrolytic cell; 19. Electrolyte inlet; 20. Electrolyte circulation filtration system; 21. Electrolyte outlet. Detailed Implementation

[0029] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. It should be noted that the specific embodiments described herein are merely one implementation of the present invention and not all of them. Based on the embodiments disclosed in this invention, all other embodiments or equivalent substitutions obtained by those skilled in the art without creative effort are within the protection scope of the claims of this invention.

[0030] A spiral anode rotating disk apparatus for electroforming additive manufacturing includes the following steps performed in sequence:

[0031] Preparations before electroforming:

[0032] The electrolyte 17 used in this embodiment has the following composition: nickel aminosulfonate concentration of 500 g / L, boric acid concentration of 30 g / L, sodium dodecyl sulfate concentration of 0.15 g / L, the pH value of electrolyte 17 is controlled at 4.0±0.2, and the temperature is maintained at 55±1℃.

[0033] like Figures 1 to 6 As shown, the present invention provides a spiral anode rotating disk device for electroforming additive manufacturing, comprising a rotating disk carrier plate 3, a wire anode 14, an auxiliary cathode 12, and a power supply system.

[0034] The lower surface of the rotating disk carrier plate 3 is machined with two spiral grooves 13 and two linear anodes 14. The two spiral grooves 13 and the two linear anodes 14 are parallel in direction of rotation, follow the trajectory of the Archimedean spiral, and are arranged alternately. The center of the rotating disk carrier plate 3 is provided with a liquid supply hole 15 for injecting electrolyte 17. The inlet 16 of the spiral groove 13 is connected to the liquid supply hole 15, and the outlet 8 of the spiral groove 13 is located at the outermost edge of the lower surface of the rotating disk carrier plate 3. The rotating disk carrier plate 3 is arranged parallel to and directly above the cathode substrate 6. The rotating disk carrier plate 3 rotates in the same direction as the Archimedean spiral and slides in the up and down direction.

[0035] The spiral groove 13 effectively improves the uniformity of metal ion concentration distribution on the surface of the cathode substrate 6 by optimizing the mass transfer process of the electrolyte 17 within the processing gap. When a traditional flat rotary disk relies solely on central liquid supply, the ion concentration of the electrolyte 17 will exhibit an uneven distribution (similar to a Gaussian distribution) with high concentration at the center and low concentration at the edges as the ions in the electrolyte 17 are continuously consumed and not replenished in time during the electroforming process, resulting in uneven thickness of the metal deposition layer 4. By setting the spiral groove 13 on the rotary disk carrier plate 3, the electrolyte 17 is guided to flow along the spiral path by centrifugal force under the rotation drive with the same direction as the spiral groove 13, which significantly enhances the radial transport capacity of the electrolyte 17 from the center to the edge, promotes the continuous replenishment and exchange of ions from the central region to the edge region, and this flow mechanism effectively reduces the radial concentration gradient within the processing gap, suppresses concentration polarization, and achieves a uniform distribution of reactive ions across the entire surface of the cathode substrate 6, thereby providing a reliable mass transfer guarantee for obtaining a metal deposition layer 4 with consistent thickness and high precision.

[0036] The auxiliary cathode 12 is embedded in the side of the rotating disk carrier plate 3, and its outer surface is flush with the side of the rotating disk carrier plate 3. The power supply system includes a power supply 11, a cathode substrate shunt 9 and an auxiliary cathode shunt 10. The anode of the power supply 11 is electrically connected to the line anode 14, and the negative terminal of the power supply 11 is independently electrically connected to the cathode substrate 6 and the auxiliary cathode 12 through the cathode substrate shunt 9 and the auxiliary cathode shunt 10, respectively.

[0037] To suppress the "edge effect" caused by the concentration of electric field lines at the geometric edge of the cathode substrate 6 and the stray electric field generated by the linear anode 14 in this region, which leads to excessively high electric field strength in the edge region and consequently excessively high local current density, this invention adds an auxiliary cathode 12. The auxiliary cathode shunt 10 independently controls the on / off state and magnitude of the current in the auxiliary cathode 12, actively absorbing and adjusting the stray electric field formed by the linear anode 14 in the edge region. This optimizes the current density distribution on the surface of the cathode substrate 6, effectively expands the processing area with uniform current density distribution, improves the radial consistency of the metal deposition layer 4 thickness, and thus enhances the material utilization efficiency of the cathode substrate 6 and the overall quality of the metal deposition layer 4.

[0038] The polar equations of the Archimedean spiral are all... Among them, the parameters of the two line anodes 14 , polar angle Take respectively , Parameters of spiral groove 13 , polar angle Take respectively , The cross-sectional dimensions of the linear anode 14 are 2 mm deep and 0.05 mm wide; the cross-sectional dimensions of the spiral groove 13 are 0.2 mm deep and 0.4 mm wide.

[0039] The wire anode 14 is made of platinum with a purity of not less than 99.999%, specifically a platinum strip with a length of 249.4 mm, a width of 0.05 mm, and a height of 2 mm. The wire anode 14 is precision-machined and embedded into the lower surface of the rotating disk carrier plate 3, and then sealed and fixed with epoxy resin (the platinum strip undergoes a series of treatments such as surface oxide layer removal before sealing) to ensure that the working surface of the wire anode 14 is flush with the lower surface of the rotating disk carrier plate 3, avoiding protrusions that interfere with the electric field.

[0040] The rotating disk carrier plate 3 is made of acid and alkali resistant electrically insulating PP material with a diameter of 80mm. A rotating shaft 2 is coaxially fixed at the liquid supply hole 15 on its upper surface. An axially extending liquid inlet channel 1 is opened inside the rotating shaft 2. Electrolyte 17 is injected from top to bottom into the liquid supply hole 15 with a central diameter of 3mm through the liquid inlet channel 1. The liquid supply flow rate is 2ml / s. The rotating disk carrier plate 3 can be rotated from 0.5 to 16r / s under the drive of the rotating shaft 2, and can also slide in the up and down direction.

[0041] The rotating shaft 2 employs a sealed design with a rotary joint, which effectively prevents electrolyte 17 from leaking along the shaft and avoids air being drawn into the processing area. This design also ensures the rotational speed stability and coaxiality of the rotating disk carrier plate 3 during operation, preventing changes in the cathode-anode spacing caused by shaft wobbling, thereby ensuring the uniformity of the metal deposition layer 4.

[0042] The cathode substrate 6 is detachably mounted on the upper surface of the cathode carrier plate 7. The cathode mask 5 is detachably and tightly attached to the upper surface of the cathode substrate 6, and then placed parallel and coaxially opposite to the rotating disk carrier plate 3 above. The processing gap between the cathode mask 5 and the rotating disk carrier plate 3 can be adjusted within the range of 0.1~1mm.

[0043] Cathode mask 5 is made of negative dry film material with a thickness of [missing information]. The cathode mask has multiple gear-shaped through holes evenly distributed around its circumference to define the areas of the deposition pattern.

[0044] The cathode substrate 6 is a disc-shaped structure made of 304 stainless steel. The working area has a diameter of 50mm and a thickness of 1~2mm. It undergoes pretreatment such as mechanical grinding, chemical degreasing, pickling and rust removal, and deionized water rinsing to ensure that the surface is clean and free of additional impurities.

[0045] During electroforming, the rotating disk carrier plate 3 is completely immersed in the electrolyte 17. The machining gap between its lower surface and the upper surface of the cathode mask 5 is set to 0.4 mm. The rotating disk carrier plate 3 rotates continuously at a speed of 4 r / s according to a preset program. The structure of the staggered arrangement of the spiral groove 13 and the wire anode 14 guides the electrolyte 17 to form a directional flow path under the action of rotation. This design significantly enhances the mixing and transport capacity of the electrolyte 17 in the inter-electrode region, promotes the continuous replenishment and exchange of reactive ions from the center to the edge, thereby effectively improving the ion mass transfer efficiency and suppressing the concentration polarization phenomenon caused by untimely replenishment of ions.

[0046] Electroforming Experimental Procedure

[0047] S1: Install and fix the cathode substrate 6 with the cathode mask 5 attached onto the cathode carrier plate 7, adjust the machining gap between the upper surface of the cathode mask 5 and the lower surface of the rotating disk carrier plate 3 to 0.4mm, and ensure that the two are parallel, aligned and coaxially immersed in the electrolytic cell 18 containing the electrolyte 17.

[0048] S2: Connect the positive terminal of power supply 11 to the wire anode 14, and the negative terminal to the auxiliary cathode 12 and cathode substrate 6 independently through the auxiliary cathode shunt 10 and cathode substrate shunt 9, respectively. Set the output voltage of power supply 11 to 7V, start the electrolyte circulation filtration system 20, so that electrolyte 17 enters the electrolytic cell 18 through the supply hole 15 and electrolyte inlet 19, and flows out through the electrolyte outlet 21 below the electrolytic cell 18. The electrolyte 17 injected at the supply hole 15 is used to enhance the ion mass transfer effect in the processing gap, and the electrolyte 17 injected at the electrolyte inlet 19 is used to maintain the full circulation of electrolyte 17. Then start the drive device of the rotating shaft 2, control the rotating disk carrier plate 3 to rotate at a speed of 4r / s according to the preset mode, actively drive the electrolyte 17 to form a directional flow in the spiral groove 13. After the flow field stabilizes, start power supply 11 to start electroforming. During the process, the pH of electrolyte 17 was monitored and maintained at 4.0±0.2 and the temperature at 55±1℃ in real time. Under the synergistic effect of the electric field and the enhanced flow field, the Ni in electrolyte 17... 2+ The metal deposition layer 4 is formed by reduction and continuous deposition on the surface of the cathode substrate 6.

[0049] S3: After electroforming for 60 minutes, turn off the power supply 11, the rotary drive device and the electrolyte circulation filtration system 20 in sequence. Remove the cathode carrier plate 7 together with the cathode substrate 6 and the cathode mask 5 from the electrolytic cell 18. After peeling off the cathode mask 5, a metal deposition layer 4 with high uniformity and high precision can be obtained, and the electroforming process is completed.

Claims

1. A helical wire anode rotating disk apparatus for electroforming additive manufacturing, characterized by: The device includes a rotating disk carrier plate (3), a linear anode (14), an auxiliary cathode (12), a power supply (11), a cathode substrate shunt (9), and an auxiliary cathode shunt (10); the lower surface of the rotating disk carrier plate (3) is provided with spiral grooves (13); the linear anode (14) is installed on the lower surface of the rotating disk carrier plate (3); an even number of spiral grooves (13) and an even number of linear anodes (14) are arranged in parallel directions, following the trajectory of the Archimedean spiral and interleaved; the center of the rotating disk carrier plate (3) is provided with a liquid supply hole (15) for injecting electrolyte (17); the spiral grooves (11) 3) The inlet (16) is connected to the liquid supply hole (15), and the outlet (8) is installed on the outermost edge of the lower surface of the rotating disk carrier plate (3); the anode of the power supply (11) is electrically connected to the line anode (14), and the negative terminal of the power supply (11) is electrically connected to the cathode substrate (6) and the auxiliary cathode (12) through the cathode substrate shunt (9) and the auxiliary cathode shunt (10), respectively; the rotating disk carrier plate (3) is arranged parallel to and directly above the cathode substrate (6); the rotating disk carrier plate (3) rotates in the same direction as the Archimedean spiral and the speed is adjusted; The auxiliary cathode (12) is embedded in the side of the rotating disk carrier plate (3), and its outer surface is flush with the side of the rotating disk carrier plate (3). The distance between the rotating disk carrier plate (3) and the cathode substrate (6) can be adjusted within the range of 0.1 mm to 0.4 mm.

2. A helical wire anode rotating disc apparatus for electroforming additive manufacturing according to claim 1, characterized in that: The trajectory of the Archimedean spiral is given by the polar equation wherein is the initial radius, mm; is the pitch coefficient, mm / rad; is the polar angle, radians ; is the polar radius, mm.

3. A helical wire anode rotating disc apparatus for electroforming additive manufacturing according to claim 2, characterized in that: The helical groove (13) has an initial radius different from that of the wire anode (14) and polar angle is arranged staggered to the wire anode (14); the helical groove (13) has a depth of 0.1 to 0.3 mm and a width of 0.3 to 0.5 mm.

4. A helical wire anode rotating disc apparatus for electroforming additive manufacturing according to claim 1, characterized in that: The line anode (14) is made of platinum with a purity of not less than 99.999% and has a width of 0.05 mm to 0.1 mm.

5. A helical wire anode rotating disc apparatus for electroforming additive manufacturing according to claim 1, characterized in that: The rotating disk carrier plate (3) is slidably disposed in the up-down direction.

6. A helical wire anode rotating disc apparatus for electroforming additive manufacturing according to claim 1, characterized in that: The line anode (14) is embedded in the lower surface of the rotating disk carrier plate (3), and its lower surface is flush with the lower surface of the rotating disk carrier plate (3).

7. A helical wire anode rotating disc apparatus for electroforming additive manufacturing according to claim 1, characterized in that: The rotational speed of the rotating disk carrier plate (3) is adjustable within the range of 0.5~16 r / s.

8. A helical wire anode rotating disc apparatus for electroforming additive manufacturing according to claim 1, characterized in that: The rotating disk carrier plate (3) is made of an electrically insulating material that is resistant to acid and alkali corrosion.

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