A Quasi-dry electrochemical mechanical polishing method for additive manufacturing components

Abstract

This invention belongs to the field of precision metal surface machining and additive manufacturing post-processing technology. It provides a quasi-dry electrochemical mechanical polishing method for additively manufactured components. The method first selects the abrasive particle size based on the initial roughness, defect size, and surface characteristics of the component surface; then, it selects the electrolyte based on the component material; next, it mixes the abrasive and electrolyte to obtain a quasi-dry polishing medium; finally, it connects the component as the anode to a pulsed power supply. Under the relative motion between the abrasive and the workpiece, the abrasive contacts the raised areas on the workpiece surface, forming a localized micro-electrolysis cell, and simultaneously performs mechanical grinding and electrochemical anodic dissolution, achieving selective material removal from surface protrusions. This invention uses ordinary high-hardness spherical abrasives instead of ion exchange resin, significantly reducing costs, increasing abrasive reusability, reducing material loss, improving polishing efficiency, and significantly reducing electrolyte consumption. It is suitable for efficient and precise post-processing of additively manufactured metal components.

Description

Technical Field

[0001] This invention relates to the field of precision machining of metal surfaces and post-processing technology of additive manufacturing, and in particular to a quasi-dry electrochemical mechanical polishing method for additive manufacturing components. Background Technology

[0002] Additive manufacturing, as an advanced manufacturing technology, can directly manufacture complex structural parts by layer-by-layer material deposition. It boasts advantages such as high forming freedom, high material utilization, and strong integrated manufacturing capabilities for complex components, and has been widely applied in aerospace, biomedicine, energy equipment, and precision molds. However, because additive manufacturing components are formed by layer-by-layer melting and deposition, problems commonly arise during the forming process, including spherical defects, powder adhesion, significant step effects, obvious molten pool textures, and large local surface undulations. This results in high initial surface roughness, typically reaching 10–50 μm (Ra). High surface roughness not only reduces the dimensional and assembly accuracy of components but also significantly affects their fatigue performance, corrosion resistance, and service life. Especially in aero-engine blades, medical implants, and high-precision flow channel components, rough surfaces easily become crack initiation sites and corrosion starting points, thus requiring post-processing polishing.

[0003] Currently, the main technologies used for electrochemical polishing of additive manufacturing components are: dry electrochemical polishing, electrochemical-mechanical composite polishing, micro-abrasive-assisted electrochemical polishing, and traditional electrochemical polishing. Among them, dry electrochemical polishing mainly uses ion exchange resin particles as the polishing medium. For example, macroporous strong acid cation exchange resin (such as type D001, with a particle size of 0.4~0.7mm) is used as the abrasive carrier. The micropores and crack structures inside the resin particles adsorb the electrolyte. During the polishing process, local micro-electrolysis cells are formed through point contact between the resin particles and the workpiece surface. Metal ions diffuse into the resin particles and are carried away, thereby achieving "dry" electrochemical polishing. However, ion exchange resin-based dry electrochemical polishing still has significant shortcomings: 1. Ion exchange resins are expensive, far exceeding the cost of ordinary industrial abrasives. For example, white corundum costs about 5-15 yuan / kg, while ion exchange resin typically costs 50-200 yuan / kg, significantly increasing processing costs; 2. The microporous structure of the resin is easily blocked by metal ions during use, leading to a decrease in the ability to adsorb electrolytes and requiring frequent replacement; 3. Ion exchange resins have low mechanical strength, with a Mohs hardness of about 2-3, resulting in weak mechanical abrasion and reliance mainly on electrochemical action, thus limiting polishing efficiency.

[0004] Micro-abrasive-assisted electrochemical polishing typically uses a mixture of high-speed flowing micro-abrasives (such as alumina or silicon carbide) and an electrolyte (such as NaNO3 solution). The high-speed abrasives wash away the passivation film from the workpiece surface, thereby accelerating the electrochemical dissolution of raised areas and protecting pitted areas, achieving surface smoothing. Although this method can reduce surface roughness from approximately Ra10μm to approximately Ra1μm and has a good polishing effect, it still relies on a large amount of liquid electrolyte, resulting in a high electrolyte consumption, typically reaching 10~20L / min. It also requires auxiliary equipment such as high-pressure pumps and circulating electrolyte supply systems, leading to complex equipment structures and high operating costs. Furthermore, for complex internal cavity structures, uneven electrolyte flow can easily cause significant differences in polishing effects in local areas, limiting its applicability.

[0005] Traditional electrochemical polishing involves immersing the entire workpiece in a large amount of electrolyte, achieving leveling by utilizing the principle that the higher current density and faster dissolution rate in the raised areas of the workpiece surface. While this method can improve surface quality, the simultaneous electrochemical dissolution at both surface peaks and valleys often requires the removal of a significant amount of substrate material to achieve the target roughness, resulting in substantial material loss. Furthermore, the use of highly corrosive acids such as phosphoric acid, perchloric acid, and sulfuric acid as electrolytes easily generates large amounts of hazardous waste, posing significant environmental problems. For additively manufactured components with large surface roughness, uneven dissolution can also lead to pitting corrosion, affecting the final surface quality.

[0006] Therefore, there is an urgent need to develop a method that can replace expensive ion exchange resins and use low-cost common abrasives to achieve quasi-dry electrochemical mechanical polishing. Summary of the Invention

[0007] The purpose of this invention is to provide a quasi-dry electrochemical mechanical polishing method for additively manufactured components, addressing the shortcomings of existing technologies. This method significantly reduces electrolyte consumption while ensuring the supply of electrolyte required for electrochemical polishing. It also achieves selective removal of raised areas and effective protection of pitted areas on the high-roughness surfaces of additively manufactured components, thereby reducing material loss, improving polishing efficiency, and realizing a synergistic enhancement effect between mechanical grinding and electrochemical dissolution.

[0008] In this invention, the surface of the common high-hardness abrasive (such as white corundum or zirconium oxide) naturally contains a large number of microcracks and micropores with a pore size of 1-50 μm. This microstructure can adsorb electrolyte through capillary action and remain stably on the abrasive surface, forming a quasi-dry liquid film layer. This liquid film is similar to a "micro-liquid bridge" partially covering the abrasive surface, contacting the workpiece surface as the abrasive moves during polishing. Because the abrasive particle size (0.2-2 mm) is much larger than the diameter of pits on the workpiece surface (50-100 μm), the abrasive only contacts spherical protrusions, stepped defects, and areas above the reference surface on the workpiece surface, and has difficulty penetrating the pit areas. Therefore, in the raised areas, the liquid film on the abrasive surface and the metal surface form a local micro-electrolysis cell. Anodic dissolution occurs preferentially in the raised areas. At the same time, the high hardness of the abrasive, under pressure, produces a mechanical micro-cutting effect on the raised areas, continuously removing the surface passivation layer and exposing the fresh metal surface, thereby accelerating the electrochemical dissolution process. In contrast, the pitted areas, due to the lack of contact with the abrasive and the absence of an electrolyte environment, do not undergo electrochemical dissolution and are thus effectively protected. This achieves a precise planarization polishing effect that selectively removes the raised areas while retaining the pits.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0010] This invention provides a quasi-dry electrochemical mechanical polishing method for additively manufactured components, comprising the following steps:

[0011] 1) Select the abrasive based on the initial roughness, defect size, and surface characteristics of the additively manufactured component;

[0012] The abrasive is a spherical abrasive, and the material of the abrasive is one or more of white corundum, zirconium oxide and silicon carbide. The particle size of the abrasive is 0.2~2mm, and the particle size of the abrasive is much larger than the diameter of the surface defect of the additive manufacturing component.

[0013] 2) Select the electrolyte based on the material of the additively manufactured component;

[0014] The electrolyte is a neutral salt electrolyte and / or an alcohol-based composite electrolyte;

[0015] 3) The abrasive and the electrolyte are mixed, and the electrolyte is adsorbed through the microcracks, micropores and rough structure on the surface of the abrasive to form a liquid film, thereby obtaining a quasi-dry polishing medium;

[0016] 4) Fix the additive manufacturing component onto the spindle fixture and connect it to the anode of the pulse power supply; connect the conductive cathode of the polishing device to the cathode of the pulse power supply; fill the polishing groove between the conductive cathode and the additive manufacturing component with the quasi-dry polishing medium;

[0017] 5) Set the processing parameters, control the processing voltage to 3~200V, the relative linear speed to 0.1~2m / s, and the polishing time to 10~60min, so that the abrasive will preferentially contact the raised areas on the surface of the additive manufacturing component under the action of relative motion, forming a local micro-electrolysis cell, and simultaneously perform mechanical grinding and electrochemical anodic dissolution to achieve selective planarization polishing of the surface of the additive manufacturing component.

[0018] Preferably, the additive manufacturing component is a powder bed melting, powder / filament feeding additive manufacturing component.

[0019] Preferably, the particle size of the abrasive in step 1) is more than 10 times the diameter of the surface defect of the additively manufactured component.

[0020] Preferably, the abrasive surface in step 1) has microcracks and micropores with a pore size of 1~50μm.

[0021] Preferably, the neutral salt electrolyte in step 2) is an aqueous solution of sodium chloride or sodium nitrate, and the mass fraction of the neutral salt electrolyte is 5-20%.

[0022] Preferably, the alcohol-based composite electrolyte is a sodium chloride / sodium nitrate-ethylene glycol mixture, wherein the concentration of sodium chloride / sodium nitrate is 0~1 mol / L.

[0023] Preferably, the mass ratio of the abrasive to the electrolyte in step 3) is 10~20:1.

[0024] Preferably, the conductive cathode in step 4) is a conductive rotary polishing disc.

[0025] Preferably, the frequency of the pulse power supply in step 4) is 0~1kHz and the duty cycle is 20~100%.

[0026] The beneficial effects of this invention include the following:

[0027] 1) Significantly reduced cost: This invention uses common industrial abrasives such as white corundum and zirconium oxide to replace the ion exchange resin used in traditional dry electrochemical polishing. The material cost is only 1 / 10 to 1 / 20 of that of ion exchange resin, which significantly reduces the processing cost.

[0028] 2) The abrasive is reusable: The abrasive described in this invention has high hardness (Mohs hardness 8~9), high mechanical strength, is not easy to wear and clog, and can be recycled multiple times, which significantly improves its service life.

[0029] 3) Reduced material loss: By controlling the abrasive particle size to be much larger than the diameter of surface defects in additively manufactured components, the abrasive preferentially contacts the raised areas of the surface, achieving selective removal of protrusions and protection of pits, thus avoiding the large amount of matrix material loss caused by the complete dissolution of traditional electrochemical polishing.

[0030] 4) Improved polishing efficiency: This invention uses the synergistic effect of mechanical grinding and electrochemical anodic dissolution to continuously remove the passivation layer and expose the fresh metal surface, which significantly improves the electrochemical dissolution efficiency. The overall polishing efficiency is 2 to 3 times higher than that of traditional electrochemical polishing.

[0031] 5) Excellent environmental performance: This invention uses neutral salt electrolyte or alcohol-based composite electrolyte, and the amount of electrolyte used is extremely small. It is in a quasi-dry processing state, avoiding the generation of a large amount of strong acid / alkali waste liquid, and has good environmental performance. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the processing principle of the quasi-dry electrochemical mechanical polishing method for additive manufacturing components of the present invention, wherein (a) is a schematic diagram of the polishing device, (b) is a physical diagram of the liquid film formation and contact on the workpiece surface, and (c) is a schematic diagram of the liquid film formation and contact on the workpiece surface.

[0033] Figure 2 The images show the surface morphology changes of the additively manufactured component under different processing times during the quasi-dry electrochemical mechanical polishing process in Example 1. (a) shows the surface morphology before processing; (b) shows the surface morphology after 30 seconds of processing; (c) shows the surface morphology after 60 seconds of processing; (d) shows the surface morphology after 180 seconds of processing; (e) shows the surface morphology after 360 seconds of processing; and (f) shows the final surface morphology after 40 minutes of continuous processing.

[0034] Figure 3 This is a surface morphology image of the additively manufactured component after mechanical polishing for 40 minutes without an electric field, as shown in Comparative Example 1. Detailed Implementation

[0035] This invention provides a quasi-dry electrochemical mechanical polishing method for additively manufactured components, comprising the following steps:

[0036] 1) Select the abrasive based on the initial roughness, defect size, and surface characteristics of the additively manufactured component;

[0037] The abrasive is preferably spherical, and the material of the abrasive is preferably one or more of white corundum, zirconium oxide and silicon carbide. The particle size of the abrasive is preferably 0.2~2mm, more preferably 0.5~1.5mm, and even more preferably 1mm. The particle size of the abrasive is preferably much larger than the diameter of the surface defect of the additively manufactured component.

[0038] 2) Select the electrolyte based on the material of the additively manufactured component;

[0039] The electrolyte is preferably a neutral salt electrolyte and / or an alcohol-based composite electrolyte;

[0040] 3) The abrasive and the electrolyte are mixed, and the electrolyte is adsorbed through the microcracks, micropores and rough structure on the surface of the abrasive to form a liquid film, thereby obtaining a quasi-dry polishing medium;

[0041] 4) Fix the additive manufacturing component onto the spindle fixture and connect it to the anode of the pulse power supply; connect the conductive cathode of the polishing device to the cathode of the pulse power supply; fill the polishing groove between the conductive cathode and the additive manufacturing component with the quasi-dry polishing medium;

[0042] 5) Set the processing parameters. The processing voltage is preferably 3~200V, more preferably 50~150V, and even more preferably 80~120V. The relative linear velocity is preferably 0.1~2m / s, more preferably 0.5~1.5m / s, and even more preferably 0.8~1.2m / s. The polishing time is preferably 10~60min, more preferably 20~50min, and even more preferably 30~40min. This allows the abrasive to preferentially contact the raised areas on the surface of the additively manufactured component under the action of relative motion, forming a local micro-electrolysis cell. Simultaneously, mechanical grinding and electrochemical anodic dissolution are performed to achieve selective planarization polishing of the surface of the additively manufactured component.

[0043] In this invention, the additive manufacturing component is preferably manufactured by powder bed melting and powder / filament feeding additive manufacturing.

[0044] Shaped components.

[0045] In this invention, the particle size of the abrasive in step 1) is preferably larger than the surface defects of the additively manufactured component.

[0046] More than 10 times the diameter, and more preferably more than 12 times the diameter of the surface defect of the additively manufactured component.

[0047] In this invention, the abrasive surface in step 1) preferably has microcracks and micropores with a pore size of 1~50μm, and the pore size of the microcracks and micropores is further preferably 10~30μm, more preferably 20μm, for adsorbing electrolyte through capillary action.

[0048] In this invention, the abrasive ensures that the electrolyte film on the workpiece surface only contacts the peaks and not the troughs, thereby achieving localized removal of the peaks.

[0049] In this invention, the neutral salt electrolyte in step 2) is preferably an aqueous solution of sodium chloride or sodium nitrate, and the mass fraction of the neutral salt electrolyte is preferably 5-20%, more preferably 10-15%, and even more preferably 12%.

[0050] In this invention, the alcohol-based composite electrolyte is preferably a sodium chloride / sodium nitrate-ethylene glycol mixture, wherein the concentration of sodium chloride / sodium nitrate is preferably 0~1 mol / L, more preferably 0.4~0.6 mol / L, and even more preferably 0.5 mol / L.

[0051] In this invention, the mass ratio of the abrasive to the electrolyte in step 3) is preferably 10~20:1, more preferably 14~16:1, and even more preferably 15:1.

[0052] In this invention, the conductive cathode in step 4) is preferably a conductive rotary polishing disc.

[0053] In this invention, the frequency of the pulse power supply in step 4) is preferably 0~1kHz, more preferably 0.4~0.6kHz, and even more preferably 0.5kHz, and the duty cycle is preferably 20~100%, more preferably 40~60%, and even more preferably 50%.

[0054] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0055] Example 1

[0056] Using a TC4 titanium alloy component formed by selective laser melting (SLM) as the research object (workpiece), its initial surface exhibits obvious spherical defects, powder adhesion, and a step effect, with a surface roughness Ra of 12.10 μm, which is typical of rough surfaces in additive manufacturing. The quasi-dry electrochemical mechanical polishing method described in this invention was used to perform precision surface polishing, and the specific steps are as follows:

[0057] First, the abrasive grain size is selected based on the initial roughness, defect size, and surface characteristics of the workpiece (the diameter of the interlayer banded groove defects on the laser powder bed fusion surface is 100~200μm). White corundum spherical abrasive is selected as the polishing medium, with a grain size of 2mm. The abrasive surface has abundant microcracks and micropores with a pore size of 10~30μm, which can adsorb electrolyte through capillary action and form a stable liquid film. Because the abrasive grain size is significantly larger than the diameter of the defects on the workpiece surface, the abrasive preferentially contacts the interlayer banded protrusions and spherical adhered powder on the workpiece surface during processing, and has difficulty penetrating into the interior of the defects.

[0058] The electrolyte is a sodium chloride-ethylene glycol mixture, with a sodium chloride concentration of 0.5 mol / L. White corundum abrasive and electrolyte are mixed at a mass ratio of 20:1, allowing a small amount of electrolyte to be adsorbed onto the abrasive surface through microcracks and micropores, forming a stable quasi-dry liquid film layer, thus constituting a quasi-dry polishing medium. This liquid film layer is similar to a micro-liquid bridge locally coating the abrasive surface, and during polishing, it can contact the raised areas of the workpiece surface to form localized micro-electrolytic cells.

[0059] Subsequently, the SLM-formed TC4 titanium alloy component is fixed on the spindle fixture and connected to the anode of the pulse power supply; the conductive rotary polishing disc in the polishing device is connected to the cathode of the pulse power supply as a conductive cathode; the quasi-dry polishing medium is filled into the polishing groove between the conductive rotary polishing disc and the workpiece, and contact pressure is applied, so that the abrasive contacts the raised area on the workpiece surface under pressure. During rotation, the conductive rotary polishing disc drives the abrasive to move, creating relative motion between the abrasive and the workpiece, and maintaining a stable mechanical grinding and electrochemical synergistic effect.

[0060] The processing parameters were set as follows: processing voltage of 200V, relative linear velocity between the abrasive and the workpiece of 0.6m / s, continuous processing time of 40min, pulse power supply frequency of 100Hz, and duty cycle of 50%. During processing, the liquid film on the abrasive surface only forms localized micro-electrolysis cells at the interlayer protrusions and adhered powder areas on the workpiece surface, where anodic dissolution occurs in the protrusion areas. Simultaneously, the abrasive grains exert a micro-cutting effect on the protrusion areas, continuously removing the surface passivation layer and exposing fresh metal surfaces, thereby accelerating the electrochemical dissolution process. Since the interior of the defects does not come into contact with the abrasive and lacks an electrolyte environment, electrochemical dissolution basically does not occur, thus achieving selective planarization polishing that prioritizes the removal of protrusions while maintaining the integrity of the interior of the defects.

[0061] Figure 1 This is a schematic diagram illustrating the processing principle of the quasi-dry electrochemical mechanical polishing method of the present invention, wherein (a) is a schematic diagram of the polishing device, (b) is a photograph of the liquid film formation and contact on the workpiece surface, and (c) is a schematic diagram of the liquid film formation and contact on the workpiece surface. Figure 1 It can be seen that the rotation of the conductive rotary polishing disc causes the abrasive grains and the workpiece to move relative to each other. The liquid film on the surface of the abrasive grains comes into contact with the protrusions on the surface of the workpiece and undergoes electrochemical dissolution. Meanwhile, the pits on the surface of the workpiece remain unchanged because they do not come into contact with the electrolyte. As the processing continues, the surface protrusions are gradually reduced, and finally the surface is flattened.

[0062] Figure 2The images show the surface morphology changes of the additively manufactured component under different processing times during the quasi-dry electrochemical mechanical polishing process in this embodiment. (a) shows the surface morphology before processing; (b) shows the surface morphology after 30 seconds of processing; (c) shows the surface morphology after 60 seconds of processing; (d) shows the surface morphology after 180 seconds of processing; (e) shows the surface morphology after 360 seconds of processing; and (f) shows the final surface morphology after 40 minutes of continuous processing. Figure 2 It can be seen that, with the increase of processing time, spherical defects and stepped features on the surface of the SLM workpiece above the reference plane are preferentially removed under the synergistic effect of mechanical grinding and electrochemical dissolution, while the concave areas on the workpiece surface remain basically intact during the defect removal process. Figure 2 As can be clearly observed in (f), the surface defects caused by the SLM process have been completely removed, while no obvious over-corrosion phenomenon has appeared on the substrate surface, indicating that the method of the present invention can achieve highly selective removal of the surface protrusion area while effectively protecting the pit area.

[0063] After 40 minutes of quasi-dry electrochemical mechanical polishing, the surface roughness of the SLM-formed TC4 titanium alloy component decreased from the initial 12.10 μm to 0.77 μm, a reduction of over 93%. Surface spherical defects and step effects were significantly reduced, resulting in a marked improvement in surface quality. This demonstrates that the present invention achieves low-cost, high-efficiency, and low-electrolyte-consumption quasi-dry electrochemical mechanical polishing by replacing traditional ion exchange resin with ordinary high-hardness abrasives, effectively improving the surface precision and service performance of additively manufactured components.

[0064] Example 2

[0065] The process is basically the same as in Example 1, except that zirconia spherical abrasive is used as the polishing medium. The abrasive has a particle size of 1 mm and a surface with abundant microcracks and micropores with a pore size of 5~20 μm. The zirconia abrasive is mixed with the electrolyte at a mass ratio of 20:1, while other conditions remain unchanged.

[0066] After 40 minutes of quasi-dry electrochemical mechanical polishing, the surface roughness Ra of the SLM-formed TC4 titanium alloy component decreased from 12.10 μm to 1.52 μm, with a roughness reduction of more than 87%. The surface spherical defects and step effects were significantly reduced, and the surface quality was significantly improved.

[0067] Example 3

[0068] The process is basically the same as in Example 1, except that silicon carbide spherical abrasive is used as the polishing medium. The abrasive has a particle size of 1.5 mm and a surface with abundant microcracks and micropores with a pore size of 20-30 μm. The electrolyte is a 10% sodium nitrate aqueous solution. The silicon carbide abrasive and the electrolyte are mixed at a mass ratio of 15:1, and other conditions remain unchanged.

[0069] After 40 minutes of quasi-dry electrochemical mechanical polishing, the surface roughness Ra of the SLM-formed TC4 titanium alloy component decreased from 12.10 μm to 1.29 μm, with a roughness reduction of more than 89%. The surface spherical defects and step effects were significantly reduced, and the surface quality was significantly improved.

[0070] Comparative Example 1

[0071] The process is basically the same as in Example 1, except that no voltage is applied (i.e., pure mechanical polishing). After 40 minutes of polishing, the surface roughness Ra decreased from 12.10 μm to 4.98 μm, and the polishing efficiency was much lower than that of quasi-dry electrochemical mechanical polishing.

[0072] The surface morphology of the additively manufactured component after mechanical polishing for 40 minutes without an electric field, as shown in the comparative example, is as follows: Figure 3 As shown.

[0073] Comparative Example 2

[0074] It is basically the same as Example 1, except that the mass ratio of abrasive to electrolyte is modified to 1:10.

[0075] After 40 minutes of quasi-dry electrochemical mechanical polishing, the surface roughness Ra of the SLM-formed TC4 titanium alloy component decreased from 12.10 μm to 1.69 μm. This is because the large amount of electrolyte caused the liquid film encapsulating the abrasive grains to be too thick, resulting in the pits also coming into contact with the electrolyte and undergoing electrochemical dissolution. As a result, both the protrusions and pits underwent electrochemical dissolution simultaneously. Although the electrochemical dissolution rate of the protrusions was greater than that of the pits, the polishing effect was still not as good as in Example 1, where the pits did not come into contact with the electrolyte and remained intact (not electrochemically dissolved).

[0076] Comparative Example 3

[0077] It is basically the same as Example 1, except that the mass ratio of abrasive to electrolyte is modified to 30:1.

[0078] After 40 minutes of quasi-dry electrochemical mechanical polishing, the surface roughness Ra of the SLM-formed TC4 titanium alloy component decreased from 12.10 μm to 3.21 μm. This is because the liquid film encapsulating the abrasive grains is too thin, resulting in thin liquid bridges between the abrasive grains. This leads to a significant decrease in the conductivity of the entire polishing medium, which in turn leads to a significant decrease in the electrochemical dissolution rate at the protrusions, thus reducing the polishing efficiency.

[0079] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A quasi-dry electrochemical mechanical polishing method for additive manufacturing components, characterized in that, It includes the following steps: 1) Select the abrasive based on the initial roughness, defect size, and surface characteristics of the additively manufactured component; The abrasive is a spherical abrasive, and the material of the abrasive is one or more of white corundum, zirconium oxide and silicon carbide. The particle size of the abrasive is 0.2~2mm, and the particle size of the abrasive is much larger than the diameter of the pit on the surface of the additively manufactured component. 2) Select the electrolyte based on the material of the additively manufactured component; The electrolyte is a neutral salt electrolyte and / or an alcohol-based composite electrolyte; 3) The abrasive and the electrolyte are mixed so that the electrolyte is adsorbed through the microcracks, micropores and rough structure on the surface of the abrasive to form a liquid film, thereby obtaining a quasi-dry polishing medium; 4) Fix the additive manufacturing component onto the spindle fixture and connect it to the anode of the pulse power supply; connect the conductive cathode of the polishing device to the cathode of the pulse power supply; fill the polishing groove between the conductive cathode and the additive manufacturing component with the quasi-dry polishing medium; 5) Set the processing parameters, control the processing voltage to 3~200V, the relative linear speed to 0.1~2m / s, and the polishing time to 10~60min, so that the abrasive will preferentially contact the raised areas on the surface of the additive manufacturing component under the action of relative motion, forming a local micro-electrolysis cell, and simultaneously perform mechanical grinding and electrochemical anodic dissolution to achieve selective planarization polishing of the surface of the additive manufacturing component.

2. The quasi-dry electrochemical mechanical polishing method for additive manufacturing components according to claim 1, characterized in that, The additive manufacturing component is a powder bed melting, powder / filament feeding additive manufacturing component.

3. A quasi-dry electrochemical mechanical polishing method for additive manufacturing components according to claim 1 or 2, characterized in that, Step 1) The particle size of the abrasive is more than 10 times larger than the diameter of the surface defect of the additively manufactured component.

4. The quasi-dry electrochemical mechanical polishing method for additive manufacturing components according to claim 3, characterized in that, Step 1) The abrasive surface has microcracks and micropores with a pore size of 1~50μm.

5. A quasi-dry electrochemical mechanical polishing method for additive manufacturing components according to claim 4, characterized in that, Step 2) The neutral salt electrolyte is an aqueous solution of sodium chloride or sodium nitrate. The mass fraction of the neutral salt electrolyte is 5-20%.

6. A quasi-dry electrochemical mechanical polishing method for additive manufacturing components according to claim 4 or 5, characterized in that, Step 2) The alcohol-based composite electrolyte is a mixture of sodium chloride / sodium nitrate and ethylene glycol, wherein the concentration of sodium chloride / sodium nitrate is 0~1 mol / L.

7. A quasi-dry electrochemical mechanical polishing method for additive manufacturing components according to claim 6, characterized in that, Step 3) The mass ratio of the abrasive to the electrolyte is 10~20:

1.

8. A quasi-dry electrochemical mechanical polishing method for additive manufacturing components according to claim 7, characterized in that, Step 4) The conductive cathode is a conductive rotary polishing disc.

9. A quasi-dry electrochemical mechanical polishing method for additive manufacturing components according to claim 7 or 8, characterized in that, Step 4) The frequency of the pulse power supply is 0~1kHz, and the duty cycle is 20~100%.

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