A dry electrolytic vibration polishing method for additive forming confined space

Abstract

The present application belongs to the technical field of part surface finishing, and aims to solve the problems of poor medium fluidity, low ion mass transfer capacity and insufficient electrochemical reaction power of the current dry electrolytic polishing. A dry electrolytic vibration polishing method for additive forming confined space is provided, comprising the following steps: selecting ion resin particles and particle size of rolling polishing blocks; compounding and proportioning the rolling polishing blocks and ion resin particles to obtain the combined medium required for polishing; assembling the polishing container and the parts to be polished; adding the combined medium to the container and covering the parts to be polished; adding an insulating liquid to the container; based on the preset horizontal vibration mechanism, vertical vibration mechanism vibration frequency and amplitude, preset DC power voltage and current, and preset rotary spindle speed, dry electrolytic vibration polishing is carried out on the parts to be polished. The present application can improve the surface roughness grade of additive forming confined space and realize uniform and consistent machining of the surface of complex shaped parts.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of part surface finishing, and particularly relates to a dry electrolytic vibration polishing method for additive forming restricted space. BACKGROUND

[0002] Modern aero-engine hot-end components present complex geometric characteristics such as multi-scale flow channels, special-shaped thin walls and irregular curved surfaces, and their extreme service conditions pose strict technical requirements on surface integrity. Traditional hot forming and mechanical processing are difficult to meet the forming precision and performance requirements of high-strength alloy large-scale integral structural parts and precise complex components. Additive manufacturing technology breaks through the technical barriers of "design-manufacturing" through a layer-by-layer deposition process, providing a new way for component lightweight and functional integration. However, in the additive forming process, phenomena such as step effect, spheroidization effect and powder adhesion lead to high surface roughness (Ra>12.5μm) and other surface quality problems such as residual tensile stress, which seriously affect the fatigue resistance and aerodynamic efficiency, so it is urgent to develop a new finishing process with low cost, high efficiency and good uniformity. Ra

[0003] Dry electrolytic polishing is a green manufacturing process based on traditional electrochemical polishing, which uses solid electrolyte particles as a medium to achieve material removal on the workpiece surface through ion transport. Chinese patent CN201780025853.2 discloses a method for smoothing and polishing metal through free solid ion transport and a solid for performing the method. Although the above process achieves good results under certain conditions, when processing additive forming restricted space parts, there are problems such as insufficient single electrochemical dissolution capacity, low material removal efficiency and excessive breakdown voltage of the passivation layer. SUMMARY

[0004] The application provides a dry electrolytic vibration polishing method for additive forming restricted space to solve at least one of the above technical problems in the prior art.

[0005] The application adopts the following technical solution: a dry electrolytic vibration polishing method for additive forming restricted space, comprising the following steps:

[0006] Based on the structural characteristics of the restricted space of the part to be polished, the particle size of the ion resin particles and the rolling polishing block is selected;

[0007] The ion resin particles are flushed by an electrolyte liquid, and the rolling polishing block and the flushed ion resin particles are compounded and matched to obtain a combined medium required for polishing;

[0008] ​Assemble the polishing container and the part to be polished; the polishing container comprises a container, a rotary main shaft, a direct current power supply, a conductive slip ring, a horizontal vibration mechanism, a rack, a rotary driving mechanism, a vertical vibration mechanism, the rotary main shaft is rotationally connected with the rack, the rotary main shaft is externally connected with the rotary driving mechanism and the vertical vibration mechanism, the rotary driving mechanism and the vertical vibration mechanism are respectively used for driving the rotary main shaft to rotate and vertically reciprocate linearly, the container is arranged at the upper end of the horizontal vibration mechanism and is externally provided with the rack, and the horizontal vibration mechanism is used for driving the container to horizontally reciprocate linearly; the part to be polished is connected at the lower end of the rotary main shaft, the cathode wire of the direct current power supply is electrically connected with the outer wall of the container, the anode of the direct current power supply is connected with the stator of the conductive slip ring through a first anode wire, the rotor of the conductive slip ring is electrically connected with the outer wall of the part to be polished through a second anode wire, and the rotor of the conductive slip ring is fixedly connected with the middle part of the rotary main shaft.

[0009] Add the combined medium into the container and over the part to be polished, add an insulating liquid into the container, start the horizontal vibration mechanism, the rotary driving mechanism, the vertical vibration mechanism and the direct current power supply, and perform dry electrolytic vibration polishing on the part to be polished.

[0010] Preferably, the ion resin particles are macroporous strong acid cation exchange resin particles, the electrolyte liquid is an acid solution or a salt solution, the acid solution is an H-type electrolyte including hydrofluoric acid, sulfuric acid, hydrochloric acid or methanesulfonic acid, the salt solution is an Na-type electrolyte including sodium fluoride or sodium sulfate, the mass fraction of the electrolyte liquid is 0.5-20 wt.%, and the electrolyte liquid is used to flush the ion resin particles to obtain ion resin particles with conductivity.

[0011] Preferably, the material of the rolling polishing block is alumina, silicon carbide or cubic boron nitride, the shape of the rolling polishing block is spherical, oblique triangular or oblique cylindrical, the rolling polishing block is formed by sintering abrasive particles, and the rolling polishing block does not electrochemically react with the ion resin particles and the electrolyte liquid.

[0012] Preferably, the ratio of the rolling polishing block to the flushed ion resin particles in the combined medium ranges from 1:1 to 1:4, and the rolling polishing block and the flushed ion resin particles are homogenously mixed by a vertical centrifugal finishing machine.

[0013] Preferably, the insulating liquid is liquid silicone or liquid paraffin, the outer wall of the rack is provided with a liquid inlet mechanism for containing the insulating liquid, the pipeline of the liquid inlet mechanism passes through the rack and the liquid inlet end is located above the container, and a pump structure for pumping the insulating liquid is arranged in the liquid inlet mechanism.

[0014] Preferably, when performing dry electrolytic vibration polishing, the preset voltage range of the DC power supply is 0~30V, and the preset current range is 0~0.5A; the preset vibration frequency range of the horizontal vibration mechanism is 5~35Hz, and the preset amplitude is 0.5~3.5mm; the preset vibration frequency range of the vertical vibration mechanism is 0~10Hz, and the preset amplitude is 0.5~2mm; the preset speed range of the rotary drive mechanism is 5~15rpm.

[0015] Preferably, to ensure smooth flow of the combined media within the confined space of the part to be polished, the relationship between the particle size of the combined media and the channel size is expressed as:

[0016]

[0017] in: For mass flow rate; Adjust the empirical coefficient for the flow rate; The density of the composite medium; Equivalent acceleration; This is the vibration-corrected flow channel diameter; Empirical coefficients for coupling correction; The coupling coefficient; The corrected diameter for non-spherical particles; The adhesion sensitivity coefficient is 0.1~0.3 for dry particles and 0.5~2 for wetted particles. This is the adhesion Bond coefficient.

[0018] Preferably, the step of solving the relationship between the particle size and the channel size of the combined medium includes:

[0019] According to the Darcy-Weisbach formula, mass flow rate With particulate medium flow rate The relationship shows that:

[0020]

[0021] The Darcy-Weisbach formula for head loss along the friction path is expressed as follows:

[0022]

[0023] in: This is due to head loss; Friction factor; The length of the flow channel; The diameter of the flow channel; For particulate media flow rate; It is the acceleration due to gravity;

[0024] mass flow With particulate medium flow rate The relationship is:

[0025]

[0026] in: For mass flow field; The pipe area; Density of particulate medium;

[0027] Therefore, the relationship between mass flow rate and channel diameter is obtained as follows: And the relationship between the mass flow field and acceleration is: Based on the dry electrolytic vibration polishing process, the following requirements are proposed for the smooth flow of the combined medium in a confined space:

[0028]

[0029] in: Adjust the empirical coefficient for the flow rate; The density of the composite medium; Equivalent acceleration;

[0030] In vibratory tumbling finishing, the particulate medium is subjected to gravity and the excitation force of the container, therefore the equivalent acceleration is:

[0031]

[0032] in: Equivalent acceleration; The amplitude of the vibration; Angular frequency, ; The vibration frequency;

[0033] Applying vibration reduces the effective friction coefficient between the combined medium and the confined space, thus shrinking the effective critical channel size. Therefore, the vibration-corrected channel diameter is:

[0034]

[0035] in: This is the vibration-corrected flow channel diameter; This is a vibration auxiliary factor, related to the particle material and vibration direction, for vertical vibration. 0.2~0.5, horizontal vibration The value is 0.1~0.3; For vibration intensity, ; It is a non-linear exponent, ranging from 0.3 to 0.7;

[0036] Using non-spherical particles increases the risk of inter-particle blockage and enlarges the critical channel size. Therefore, the corrected diameter of the non-spherical particles is:

[0037]

[0038] in: The corrected diameter for non-spherical particles; The equivalent diameter of the non-spherical particle; Sphericity; ;

[0039] When particles have viscosity, the adhesive force increases the tendency to clog, thus increasing the effective critical channel size. Therefore, the adhesive Bond number is obtained as follows:

[0040]

[0041] in: For the Bond coefficient of adhesion;

[0042] Considering the synergistic effect of particle shape and vibrational motion, a coupling coefficient is proposed:

[0043]

[0044] in: The coupling coefficient; This is the cross-coupling coefficient, ranging from 0.1 to 0.3;

[0045] Finally, the relationship between the particle size and the flow channel size of the combined medium was obtained.

[0046] Compared with the prior art, the beneficial effects of the present invention are:

[0047] To address the finishing requirements of complex internal cavities and irregularly shaped flow channels in additive manufacturing, this invention proposes a dry electrolytic vibration polishing method for confined spaces in additive manufacturing. By combining ion exchange resin particles and tumble polishing blocks in a composite ratio, a high-flowability particle system is constructed under the drive of a vibration field. The synergistic effect of electric field, flow field, and chemical field is used to enhance the electrochemical reaction kinetics process, overcoming the bottleneck problems in dry electrolytic polishing, such as blind spots in confined areas, ion diffusion lag, and high reaction activation energy caused by insufficient medium flowability. This provides a new solution for low-cost, efficient, and uniform finishing of complex cavities in additive components. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a flowchart of the dry electrolytic vibration polishing method of the present invention;

[0050] Figure 2 This is an assembly structure diagram of the polishing container and the parts to be polished according to the present invention;

[0051] Figure 3 This is a schematic diagram comparing the surface roughness of the part to be polished before and after processing according to the present invention (when the part to be polished is not rotating).

[0052] Figure 4 This is a schematic diagram comparing the residual stress of the workpiece before and after polishing according to the present invention (when the workpiece is not rotated).

[0053] Figure 5 This is a schematic diagram showing the distribution of surface elements of the part to be polished before processing (when the part to be polished is not rotating).

[0054] Figure 6 This is a schematic diagram showing the distribution of surface elements of the part to be polished after processing (when the part to be polished is not rotating).

[0055] Figure 7 This is a schematic diagram showing the surface roughness distribution of the part to be polished before and after processing according to the present invention (when the part to be polished is not subjected to vertical vibration).

[0056] Figure 8 This is a schematic diagram of the surface morphology of the part to be polished before processing according to the present invention;

[0057] Figure 9 This is a schematic diagram of the surface morphology of the part to be polished after processing (when the part to be polished is not subjected to vertical vibration).

[0058] Figure 10 This is a cross-sectional schematic diagram (top view) of the connection between the frame and the conductive slip ring of the present invention.

[0059] In the diagram: 1-rotary drive mechanism; 2-shaft sleeve; 3-eccentric wheel; 4-vertical vibration drive motor; 5-pipeline; 6-liquid inlet mechanism; 7-frame; 8-ion exchange resin particles; 9-rolling polishing block; 10-horizontal vibration mechanism; 11-container; 12-part to be polished; 13-DC power supply; 14-cathode wire; 15-first anode wire; 16-rotary spindle; 17-conductive slip ring; 18-vertical vibration slide rail; 19-slider; 20-second anode wire. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should fall within the scope of the technical content disclosed in the present invention. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0062] Example 1:

[0063] like Figure 1 As shown, a dry electrolytic vibration polishing method for additive manufacturing in confined spaces includes the following steps:

[0064] S1: Based on the structural characteristics of the confined space of the part 12 to be polished, the particle size of the ion exchange resin particles 8 and the tumble polishing block 9 is selected.

[0065] S2: The ion exchange resin particles 8 are flushed with an electrolyte liquid, and the tumbling polishing block 9 and the flushed ion exchange resin particles 8 are mixed in a composite ratio to obtain the combined medium required for polishing; in this embodiment, to ensure smooth flow of the combined medium in the confined space of the part 12 to be polished, the relationship between the particle size and the flow channel size of the combined medium is expressed as:

[0066]

[0067] in: For mass flow rate; Adjust the empirical coefficient for the flow rate; The density of the composite medium; Equivalent acceleration; This is the vibration-corrected flow channel diameter; Empirical coefficients for coupling correction; The coupling coefficient; The corrected diameter for non-spherical particles; The adhesion sensitivity coefficient is 0.1~0.3 for dry particles and 0.5~2 for wetted particles. This is the adhesion Bond coefficient.

[0068] Specifically, the steps for determining the relationship between particle size and channel size in the combined medium include:

[0069] According to the Darcy-Weisbach formula, mass flow rate With particulate medium flow rate The relationship shows that:

[0070]

[0071] The Darcy-Weisbach formula for head loss along the friction path is expressed as follows:

[0072]

[0073] in: This is due to head loss; Friction factor; The length of the flow channel; The diameter of the flow channel; For particulate media flow rate; It is the acceleration due to gravity;

[0074] mass flow With particulate medium flow rate The relationship is:

[0075]

[0076] in: For mass flow field; The pipe area; Density of particulate medium;

[0077] Therefore, the relationship between mass flow rate and channel diameter is obtained as follows: And the relationship between the mass flow field and acceleration is: Based on the dry electrolytic vibration polishing process, the following requirements are proposed for the smooth flow of the combined medium in a confined space:

[0078]

[0079] in: Adjust the empirical coefficient for the flow rate; The density of the composite medium; Equivalent acceleration;

[0080] In vibratory tumbling finishing, the particulate medium is subjected to gravity and the excitation force of the container, therefore the equivalent acceleration is:

[0081]

[0082] in: Equivalent acceleration; The amplitude of the vibration; Angular frequency, ; The vibration frequency;

[0083] Applying vibration reduces the effective friction coefficient between the combined medium and the confined space, thus shrinking the effective critical channel size. Therefore, the vibration-corrected channel diameter is:

[0084]

[0085] in: This is the vibration-corrected flow channel diameter; This is a vibration auxiliary factor, related to the particle material and vibration direction, for vertical vibration. 0.2~0.5, horizontal vibration The value is 0.1~0.3; For vibration intensity, ; It is a non-linear exponent, ranging from 0.3 to 0.7;

[0086] Using non-spherical particles increases the risk of inter-particle blockage and enlarges the critical channel size. Therefore, the corrected diameter of the non-spherical particles is:

[0087]

[0088] in: The corrected diameter for non-spherical particles; The equivalent diameter of the non-spherical particle; Sphericity; ;

[0089] When particles have viscosity, the adhesive force increases the tendency to clog, thus increasing the effective critical channel size. Therefore, the adhesive Bond number is obtained as follows:

[0090]

[0091] in: For the Bond coefficient of adhesion;

[0092] Considering the synergistic effect of particle shape and vibrational motion, a coupling coefficient is proposed:

[0093]

[0094] in: The coupling coefficient; This is the cross-coupling coefficient, ranging from 0.1 to 0.3;

[0095] By combining the above factors and the synergistic effects among them, the relationship between particle size and channel size of the combined medium is obtained.

[0096] Furthermore, the part to be polished 12 is an additively formed confined space part, a high-temperature alloy 3D printed specimen prepared using a BLT-A160 equipment. The additively formed alloy material includes GH4169 or GH4586. GH4169 is a precipitation-strengthened nickel-based high-temperature alloy, and GH4586 is a nickel-chromium-cobalt-based precipitation-hardening wrought high-temperature alloy. The ion exchange resin particles 8 are macroporous strong acidic cation exchange resin particles. The electrolyte liquid is an acid solution or a salt solution, wherein the acid solution is an H-type electrolyte, including hydrofluoric acid, sulfuric acid, hydrochloric acid, or methanesulfonic acid; the salt solution is a Na-type electrolyte, including sodium fluoride or sodium sulfate; the mass fraction of the electrolyte liquid is 0.5~20 wt.%. The ion exchange resin particles 8 are rinsed with the electrolyte liquid to obtain conductive ion exchange resin particles 8. The material of the tumbling polishing block 9 is alumina, silicon carbide or cubic boron nitride, and the shape of the tumbling polishing block 9 is spherical, oblique triangular or oblique cylindrical; the tumbling polishing block 9 is formed by sintering abrasive grains, and the tumbling polishing block 9 does not undergo electrochemical reaction with the ion exchange resin particles 8 and the electrolyte liquid.

[0097] The ratio of the tumbling polishing block 9 to the rinsed ion exchange resin particles 8 in the combined medium is in the range of 1:1 to 1:4; the tumbling polishing block 9 and the rinsed ion exchange resin particles 8 are homogenized and mixed by a vertical centrifugal finishing machine.

[0098] In this example, the mass fraction of the electrolyte liquid is 10 wt.%, and the electrolyte liquid is prepared from hydrochloric acid and deionized water; the tumbling polishing block 9 is a spherical alumina polishing block, and the ratio of the tumbling polishing block 9 to the rinsed ion exchange resin particles 8 is 4:1.

[0099] S3: Assemble the polishing container and the parts to be polished 12; such as Figure 2As shown, the polishing container includes a container 11, a rotary spindle 16, a DC power supply 13, a conductive slip ring 17, a horizontal vibration mechanism 10, a frame 7, a rotary drive mechanism 1, and a vertical vibration mechanism. The rotary spindle 16 is movably connected to the frame 7. The rotary drive mechanism 1 and the vertical vibration mechanism are externally connected to the rotary spindle 16. The rotary drive mechanism 1 and the vertical vibration mechanism are used to drive the rotary spindle 16 to perform rotation and vertical reciprocating linear motion, respectively. The container 11 is located at the upper end of the horizontal vibration mechanism 10 and is surrounded by the frame 7. Structure 10 drives container 11 to perform horizontal reciprocating linear motion; the part to be polished 12 is connected to the lower end of rotary spindle 16, the cathode wire 14 of DC power supply 13 is electrically connected to the outer wall of container 11, the anode of DC power supply 13 is connected to the stator of conductive slip ring 17 via first anode wire 15, the rotor of conductive slip ring 17 is electrically connected to the outer wall of part to be polished 12 via second anode wire 20, the rotor of conductive slip ring 17 is fixedly connected to the middle of rotary spindle 16, and the stator of conductive slip ring 17 is slidably connected to frame 7. Figure 10 As shown, the stator outer periphery of the conductive slip ring 17 is provided with a pair of ears with guide grooves, and the frame 7 is provided with guide bars that slide with the guide grooves, so that the conductive slip ring 17 and the rotary spindle 16 can move up and down within a set range under the drive of the vertical vibration mechanism.

[0100] In this application, the main structure of the vertical vibration mechanism is existing technology, which has been disclosed in Chinese Patent CN202310141864.4. A brief description follows: The output end of the vertical vibration drive motor 4 of the vertical vibration mechanism is connected to an eccentric wheel 3. A lever is provided on the eccentric wheel 3. The eccentric wheel 3 is connected to the bushing 2 on the outside of the rotary spindle 16 through the lever, causing the bushing 2 and the rotary spindle 16 to slide up and down. The rotary drive mechanism 1 is installed on the upper end of the bushing 2. Bearings are provided at both ends of the bushing 2. The rotary spindle 16 is rotatably connected to the bearings. A slider 19 is provided on one side of the bushing 2. A vertical vibration slide rail 18 that cooperates with the slider 19 is installed on the frame 7. The specific principle is: the vertical vibration drive motor 4 drives the eccentric wheel 3 to rotate, which in turn drives the bushing 2 to slide up and down. The bushing 2 drives the rotary spindle 16 to move up and down, ultimately achieving vertical vibration of the part 12 to be polished.

[0101] S4: Add the combined medium to the container 11, ensuring it covers the part 12 to be polished. Simultaneously, add an insulating liquid to the container 11. The insulating liquid is used to improve the fluidity of the combined medium and suppress the evaporation of the electrolyte liquid. The insulating liquid is liquid silicone or liquid paraffin. The outer wall of the frame 7 is provided with a liquid inlet mechanism 6 for containing the insulating liquid. The pipe 5 of the liquid inlet mechanism 6 passes through the frame 7 and the liquid inlet end is located above the container 11. The liquid inlet mechanism 6 is provided with a pump structure for pumping the insulating liquid into the container 11.

[0102] S5: Start the horizontal vibration mechanism 10, the vertical vibration mechanism, and the DC power supply 13 to perform dry electrolytic vibration polishing on the part 12 to be polished. In Example 1, no rotational motion is performed; the preset voltage range of the DC power supply 13 is 0~30V, and the preset current range is 0~0.5A; the preset vibration frequency range of the horizontal vibration mechanism 10 is 5~35Hz, and the preset amplitude is 0.5~3.5mm; the preset vibration frequency range of the vertical vibration mechanism is 0~10Hz, and the preset amplitude is 0.5~2mm.

[0103] In this embodiment, the preset vibration frequency of the horizontal vibration mechanism 10 is 25Hz and the amplitude is 3.5mm; the preset voltage of the DC power supply 13 is 15V and the current is 0.4A; and the preset vibration frequency of the vertical vibration mechanism is 10Hz and the amplitude is 2mm.

[0104] Processing effect: After 1.5 hours of combined media polishing, the surface roughness of the part to be polished 12 is... Ra The value decreased from 10.342 μm to 1.126 μm, a decrease of 88.89%; the residual tensile stress increased from 399.1 MPa to 485.2 MPa. The combined medium effectively enhanced the polishing effect and surface strengthening ability, suppressing the adverse effects of electrochemical exothermic growth on residual tensile stress. The surface elemental energy spectrum peak distribution of the polished part 12 after polishing with both media was consistent with that of the unprocessed specimen. The total mass percentage of O and S elements decreased from 8.40% to 5.61%, improving the surface cleanliness of the workpiece. Figures 3-5 As shown. Figures 5 to 6 In this system, Ni represents nickel; Cr represents chromium; Fe represents iron; C represents carbon; O represents oxygen; and S represents sulfur.

[0105] Example 2:

[0106] The difference between Example 2 and Example 1 is as follows:

[0107] In step S5: the horizontal vibration mechanism 10, the rotary drive mechanism 1, and the DC power supply 13 are started to perform dry electrolytic vibration polishing on the part 12 to be polished. Vertical vibration is not performed in Example 2.

[0108] Processing effect: After 1.5 hours of combined media polishing, the surface roughness of the part to be polished 12 is... Ra The value decreased from 10.258 μm to 4.606 μm, a decrease of 55.10%, indicating that unmelted powder was removed and surface quality was improved. Figures 7 to 9 As shown. Figure 8 , Figure 9Sa is the arithmetic mean of the absolute heights of all points within the measurement area (relative to the reference plane); Sq represents the root mean square value of Z(X,Y) within a defined area; Sz is the sum of the vertical distances between the highest peak and the deepest valley within the measurement area.

[0109] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dry electrolytic vibration polishing method for additive manufacturing in confined spaces, characterized in that, Includes the following steps: Based on the structural characteristics of the confined space of the part to be polished (12), the particle size of the ion exchange resin particles (8) and the tumble polishing block (9) is selected; The ion exchange resin particles (8) are flushed with an electrolyte liquid, and the tumbling polishing block (9) and the flushed ion exchange resin particles (8) are combined to obtain the combined medium required for polishing. Assemble the polishing container and the parts to be polished (12); the polishing container includes a container (11), a rotary spindle (16), a DC power supply (13), a conductive slip ring (17), a horizontal vibration mechanism (10), a frame (7), a rotary drive mechanism (1), and a vertical vibration mechanism. The rotary spindle (16) is rotatably connected to the frame (7). The rotary spindle (16) is externally connected to the rotary drive mechanism (1) and the vertical vibration mechanism. The rotary drive mechanism (1) and the vertical vibration mechanism are used to drive the rotary spindle (16) to rotate and perform vertical reciprocating linear motion, respectively. The container (11) is set at the upper end of the horizontal vibration mechanism (10) and the frame (7) is mounted on its outer periphery. The horizontal vibration mechanism (10) is used to drive the container (11) to perform horizontal reciprocating linear motion; the part to be polished (12) is connected to the lower end of the rotary spindle (16), the cathode wire (14) of the DC power supply (13) is electrically connected to the outer wall of the container (11), the anode of the DC power supply (13) is connected to the stator of the conductive slip ring (17) via the first anode wire (15), the rotor of the conductive slip ring (17) is electrically connected to the outer wall of the part to be polished (12) via the second anode wire (20), the rotor of the conductive slip ring (17) is fixedly connected to the middle part of the rotary spindle (16), and the stator of the conductive slip ring (17) is slidably connected to the frame (7); Add the combined medium into the container (11) and submerge the part to be polished (12). At the same time, add insulating liquid into the container (11), start the horizontal vibration mechanism (10), the rotary drive mechanism (1), the vertical vibration mechanism and the DC power supply (13) to perform dry electrolytic vibration polishing on the part to be polished (12). To ensure smooth flow of the combined media within the confined space of the part to be polished (12), the relationship between the particle size of the combined media and the channel size is expressed as: in: For mass flow rate; Adjust the empirical coefficient for the flow rate; The density of the composite medium; Equivalent acceleration; This is the vibration-corrected flow channel diameter; Empirical coefficients for coupling correction; The coupling coefficient; The corrected diameter for non-spherical particles; The adhesion sensitivity coefficient is 0.1~0.3 for dry particles and 0.5~2 for wetted particles. This is the adhesion Bond coefficient.

2. The dry electrolytic vibration polishing method for additive manufacturing in confined spaces according to claim 1, characterized in that: The ion exchange resin particles (8) are macroporous strong acidic cation exchange resin particles. The electrolyte liquid is an acid solution or a salt solution. The acid solution is an H-type electrolyte, including hydrofluoric acid, sulfuric acid, hydrochloric acid or methanesulfonic acid. The salt solution is a Na-type electrolyte, including sodium fluoride or sodium sulfate. The mass fraction of the electrolyte liquid is 0.5~20 wt.%. The ion exchange resin particles (8) are rinsed with the electrolyte liquid to obtain conductive ion exchange resin particles (8).

3. The dry electrolytic vibration polishing method for additive manufacturing in confined spaces according to claim 2, characterized in that: The material of the tumbling polishing block (9) is alumina, silicon carbide or cubic boron nitride, and the shape of the tumbling polishing block (9) is spherical, oblique triangular or oblique cylindrical; the tumbling polishing block (9) is a structure formed by sintering abrasive grains.

4. The dry electrolytic vibration polishing method for additive manufacturing in confined spaces according to claim 3, characterized in that: The ratio of the tumbling polishing block (9) and the washed ion exchange resin particles (8) in the combined medium is 1:1 to 1:4; the tumbling polishing block (9) and the washed ion exchange resin particles (8) are homogenized and mixed by a vertical centrifugal finishing machine.

5. The dry electrolytic vibration polishing method for additive manufacturing in confined spaces according to claim 4, characterized in that: The insulating liquid is liquid silicone or liquid paraffin. The outer wall of the frame (7) is provided with a liquid inlet mechanism (6) for containing the insulating liquid. The pipe (5) of the liquid inlet mechanism (6) passes through the frame (7) and the liquid inlet end is located above the container (11). The liquid inlet mechanism (6) is provided with a pump structure for pumping the insulating liquid into the container (11).

6. The dry electrolytic vibration polishing method for additive manufacturing in confined spaces according to claim 1, characterized in that: When performing dry electrolytic vibration polishing, the preset voltage range of the DC power supply (13) is 0~30V, and the preset current range is 0~0.5A; the preset vibration frequency range of the horizontal vibration mechanism (10) is 5~35Hz, and the preset amplitude is 0.5~3.5mm; the preset vibration frequency range of the vertical vibration mechanism is 0~10Hz, and the preset amplitude is 0.5~2mm; the preset rotation speed range of the rotary drive mechanism (1) is 5~15rpm.

7. The dry electrolytic vibration polishing method for additive manufacturing in confined spaces according to claim 1, characterized in that: The steps to determine the relationship between particle size and channel size in a combined medium include: According to the Darcy-Weisbach formula, mass flow rate With particulate medium flow rate The relationship shows that: The Darcy-Weisbach formula for head loss along the friction path is expressed as follows: in: This is due to head loss; Friction factor; The length of the flow channel; The diameter of the flow channel; For particulate media flow rate; It is the acceleration due to gravity; mass flow With particulate medium flow rate The relationship is: in: For mass flow field; The pipe area; Density of particulate medium; Therefore, the relationship between mass flow rate and channel diameter is obtained as follows: And the relationship between the mass flow field and acceleration is: Based on the dry electrolytic vibration polishing process, the following requirements are proposed for the smooth flow of the combined medium in a confined space: in: Adjust the empirical coefficient for the flow rate; The density of the composite medium; Equivalent acceleration; In the vibratory tumbling finishing process, the particulate medium is subjected to gravity and the excitation force of the container (11), and the equivalent acceleration is: in: Equivalent acceleration; The amplitude of the vibration; Angular frequency, ; The vibration frequency; Applying vibration reduces the effective friction coefficient between the combined medium and the confined space, thus shrinking the effective critical channel size. The vibration-corrected channel diameter is: in: This is the vibration-corrected flow channel diameter; This is a vibration auxiliary factor, related to the particle material and vibration direction, for vertical vibration. 0.2~0.5, horizontal vibration The value is 0.1~0.3; For vibration intensity, ; It is a non-linear exponent, ranging from 0.3 to 0.7; Using non-spherical particles increases the risk of inter-particle blockage, thus enlarging the critical channel size. The corrected diameter of the non-spherical particles is: in: The corrected diameter for non-spherical particles; The equivalent diameter of the non-spherical particle; Sphericity; ; When particles have viscosity, the adhesive force increases the tendency to clog, thus expanding the effective critical channel size, resulting in the adhesive Bond number: in: For the Bond coefficient of adhesion; Considering the synergistic effect of particle shape and vibrational motion, a coupling coefficient is proposed: in: The coupling coefficient; This is the cross-coupling coefficient, ranging from 0.1 to 0.3; Finally, the relationship between the particle size and the flow channel size of the combined medium was obtained.

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