Photocuring metal green body cleaning solution and preparation and cleaning methods thereof

Abstract

The invention discloses a photocuring metal green body cleaning solution and a preparation and cleaning method thereof. The cleaning solution comprises the following components in percentage by mass: 75-90% of a main solvent (propylene glycol methyl ether acetate and the like), 8-25% of a cosolvent (ethanol and the like), 0.1-0.5% of a metal passivator, 0.5-2% of a surfactant and 0.05-0.2% of a corrosion inhibitor. The main solvent and the cosolvent synergistically improve the dissolving capacity, and the solubility is improved by 25%-35% compared with that of a single solvent; the surfactant promotes permeation and removes hidden residues; the passivator and the corrosion inhibitor form dual protection, and metal corrosion is inhibited. During preparation, all the components are ultrasonically dispersed and dissolved to obtain uniform liquid. 1-5 min ultrasonic treatment is combined with air gun purging in cleaning, residual slurry on the surface of the green body of a complex structure and in micropores can be efficiently removed, the structural integrity of the green body is protected, and the method is suitable for post-treatment of thin-wall high-precision parts.

Description

Technical Field

[0001] This application belongs to the field of cleaning, and specifically relates to a photocurable metal green body cleaning solution and its preparation and cleaning method. Background Technology

[0002] During the photopolymerization process of metal preforms, due to the fluidity of the photosensitive resin, the diffusion effect of the exposure boundary, and the interlayer bonding characteristics, liquid metal slurry that has not undergone photopolymerization (hereinafter referred to as "residual slurry") remains on the surface, in the interlayer gaps, and in the internal pores of the photopolymerized metal preform. The presence of residual slurry directly affects the stability of subsequent processes and the quality of the final part: on the one hand, if the residual slurry is not completely removed during the degreasing stage, it is prone to carbonization and cracking at high temperatures, and the generated gas may cause pores, cracks, and deformation in the sintered part; on the other hand, the residual slurry forms a sticky layer on the surface of the preform, causing metal powder agglomeration during subsequent degreasing / sintering, reducing the density and mechanical properties (such as tensile strength and hardness) of the part. Therefore, thoroughly removing residual slurry after photopolymerization of the metal preform is a key post-processing step that determines the quality of metal additive manufacturing parts, and developing efficient and stable special cleaning fluids has become one of the core technical requirements in this field.

[0003] Currently, solutions for cleaning residual slurry from photocurable metal preforms mainly rely on traditional solvent-based and water-based cleaning solutions. However, these solutions have insurmountable technical drawbacks in terms of cleaning efficiency, environmental safety, and preform compatibility. The most widely used traditional solvent-based cleaning solutions are acetone, ethanol, isopropanol, and ethyl acetate. These solvents remove residual slurry by dissolving the photosensitive resin. While they offer a fast initial dissolution rate, their high volatility can cause cracking in the cleaned preform and poses environmental and safety risks. Water-based cleaning solutions primarily use water as a base, with added surfactants and co-solvents. However, they suffer from low cleaning efficiency, easy deformation of the preform, and cracking during subsequent degreasing due to residual moisture on the preform surface. Summary of the Invention

[0004] This application provides a photocurable metal green body cleaning solution and its preparation and cleaning method, in order to overcome the shortcomings of existing cleaning solutions in terms of removal efficiency, green body structure stability and environmental safety.

[0005] To achieve the above objectives, this application provides a photocurable metal green body cleaning solution, comprising the following components by mass fraction: 75%–90% main solvent, 8%–25% co-solvent, 0.1%–0.5% metal passivator, 0.5%–2% surfactant, and 0.05%–0.2% corrosion inhibitor.

[0006] In one embodiment, the main solvent is selected from one or more combinations of propylene glycol methyl ether acetate, γ-butyrolactone, limonene, dodecane, and tetradecane.

[0007] In one embodiment, the co-solvent is selected from one or more combinations of ethanol, isopropanol, and ethyl acetate.

[0008] In one embodiment, the metal passivating agent is selected from hydroxyethylidene diphosphonic acid and methylbenzotriazole.

[0009] In one embodiment, the surfactant is selected from one or more combinations of silane coupling agents, fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, and sorbitol esters.

[0010] In one embodiment, the corrosion inhibitor is selected from sodium molybdate and sodium tungstate.

[0011] A method for preparing a photocurable metal green body cleaning solution involves weighing a main solvent, a co-solvent, a metal passivator, a surfactant, and a corrosion inhibitor by mass percentage, adding the above components to a mixing container, and then using ultrasonic treatment to fully disperse and dissolve the components to obtain a uniform and transparent photocurable metal green body cleaning solution.

[0012] A cleaning method for a photocurable metal green blank involves immersing the photocurable metal green blank in the cleaning solution and using an ultrasonic cleaning device to perform auxiliary cleaning on the green blank. After the auxiliary cleaning is completed, an air gun is used to blow away the cleaning solution from the surface and crevices of the green blank, and finally, a metal green blank is obtained.

[0013] In one embodiment, the auxiliary cleaning time is 1 min to 5 min.

[0014] Compared with the prior art, the beneficial effects of this application are: 1. Effectively and thoroughly removes residual slurry, meeting the degreasing requirements of high-precision parts. By constructing a synergistic cleaning mechanism of "main solvent dissolution + co-solvent enhancement + surfactant penetration," the system improves the efficiency and thoroughness of slurry removal. The main solvent can quickly coat the surface of the green body and shallow residual slurry, achieving "dissolution upon contact," with cleaning efficiency superior to traditional acetone cleaning methods. The co-solvent further enhances the system's dissolving capacity, breaking through the limitations of single solvents in dissolving specific resins, increasing the solubility of the cleaning solution for photosensitive resins by 25%–35%. The surfactant can significantly reduce interfacial tension, promoting the penetration of the cleaning solution into the micropores and interlayer gaps inside the green body, effectively removing residual slurry that is difficult to reach with traditional methods.

[0015] 2. Strong compatibility, protects the integrity of the green body structure, and inhibits metal corrosion. A dual protection system of "passivation + corrosion inhibition" is employed to achieve comprehensive protection for metal green blanks. The metal passivator rapidly forms a dense monomolecular passivation film on the surface of powders such as titanium alloys, stainless steel, and aluminum alloys, blocking the corrosion path of the cleaning solution. The corrosion inhibitor specifically inhibits localized corrosion caused by trace impurities in the cleaning solution, particularly suitable for highly reactive titanium alloy green blanks, effectively preventing the formation of pitting corrosion. The synergistic effect of these two agents ensures effective cleaning while preventing excessive swelling of the cured resin, significantly reducing the deformation rate of thin-walled green blanks after cleaning and meeting the stringent dimensional stability requirements of high-precision parts. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 The image shows the surface morphology of the photocurable metal preform after cleaning according to the present application under an optical electron microscope. Figure 2 This is an image of the internal structure of the photocured metal preform after cleaning, as shown in an optical electron microscope. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0019] See Figures 1 to 2 As shown, the photocurable metal green body cleaning solution provided in this application comprises the following components by mass fraction: 75% to 90% main solvent, 8% to 25% co-solvent, 0.1% to 0.5% metal passivator, 0.5% to 2% surfactant, and 0.05% to 0.2% corrosion inhibitor.

[0020] The main solvent is selected from one or more combinations of propylene glycol methyl ether acetate, γ-butyrolactone, limonene, dodecane, and tetradecane. The co-solvent is selected from one or more combinations of ethanol, isopropanol, and ethyl acetate. The metal passivating agent is selected from one of hydroxyethylidene diphosphonic acid and methylbenzotriazole. The surfactant is selected from one or more combinations of silane coupling agents (KH550, KH560, KH570), fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and sorbitan ester. The corrosion inhibitor is selected from one of sodium molybdate and sodium tungstate.

[0021] In this embodiment, by constructing a synergistic dissolution system of a main solvent and a co-solvent, and combining it with the penetration-enhancing effect of a surfactant, the cleaning solution's ability to remove residual slurry from the surface and micropores of complex-structured green bodies is significantly improved. Simultaneously, the main solvent can quickly encapsulate the surface of the metal green body and shallow residual slurry, achieving immediate dissolution upon contact and significantly improving cleaning efficiency. The co-solvent further enhances the system's dissolution capacity for photosensitive resin, increasing solubility by 25%–35% compared to a single solvent, effectively shortening cleaning time. The surfactant reduces the interfacial tension between the cleaning solution and the metal green body, promoting its penetration into the microporous structure and interlayer gaps, thereby removing residual slurry from hidden areas.

[0022] Furthermore, through the synergistic protection mechanism of metal passivators and corrosion inhibitors, the metal passivator forms a dense monomolecular passivation film on the surface of the metal powder during the cleaning process, blocking the corrosion path of the cleaning solution to the metal substrate and effectively inhibiting the oxidative dissolution of active metals such as titanium alloys and stainless steel. The corrosion inhibitor, in conjunction with the passivation film, inhibits localized micro-area electrochemical corrosion and prevents the formation of pitting and intergranular corrosion. This dual protection system ensures efficient cleaning while maintaining the structural integrity of the green blank, making it particularly suitable for the post-processing of thin-walled, high-precision metal parts. It significantly reduces dimensional deformation and surface defects caused by cleaning, ensuring the dimensional accuracy and mechanical property stability of subsequent processes.

[0023] A method for preparing a photocurable metal green body cleaning solution, characterized in that: a main solvent, a co-solvent, a metal passivator, a surfactant, and a corrosion inhibitor are weighed according to mass percentage, and the above components are added to a mixing container. The components are then fully dispersed and dissolved by ultrasonic treatment to obtain a uniform and transparent photocurable metal green body cleaning solution.

[0024] A cleaning method for photocurable metal green blanks involves immersing the green blank in the cleaning solution and using an ultrasonic cleaning device for auxiliary cleaning. After the auxiliary cleaning is completed, an air gun is used to blow away the cleaning solution from the surface and crevices of the green blank, ultimately obtaining the metal green blank. The auxiliary cleaning time is 1 to 5 minutes.

[0025] The present invention will be further described below with reference to specific embodiments. It should be understood that conventional instruments and equipment in the art are used in the following embodiments. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Various raw materials used in the following embodiments are all conventional commercially available products with specifications in the art, unless otherwise stated. In the specification of this invention and in the following embodiments, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0026] Example 1

[0027] 80% of the main solvent propylene glycol methyl ether acetate, 18% of the co-solvent ethanol, 0.5% of the metal passivator hydroxyethylidene diphosphonic acid, 1.4% of the surfactant KH550, and 0.1% of the corrosion inhibitor sodium molybdate were mixed and dispersed and fully dissolved by ultrasonic treatment to obtain a uniform and transparent photocurable metal green body cleaning solution.

[0028] The photocurable metal green blank with a void size of 0.17 mm was immersed in the cleaning solution prepared above, and then treated with an ultrasonic cleaner for 1 minute. Then, the surface and internal channels of the green blank were blown with an air gun to thoroughly remove the residual slurry in the channels, and a clean metal green blank with a complete structure was obtained.

[0029] The cleaned metal billet was observed under a scanning electron microscope, as follows: Figure 1 As shown, there are no residues on the surface, the edges of the channels are clear, and no signs of corrosion are visible.

[0030] like Figure 2 As shown, the cleaned metal billet has smooth and intact channel walls, without collapse or cracks, and the slurry residue has been completely removed.

[0031] Example 2

[0032] 75% of the main solvent γ-butyrolactone, 24% of the co-solvent isopropanol, 0.45% of the metal passivator methylbenzotriazole, 0.5% of the surfactant KH560, and 0.05% of the corrosion inhibitor sodium molybdate were mixed and ultrasonically treated to fully disperse and dissolve the mixture, resulting in a uniform and transparent light-cured metal green body cleaning solution.

[0033] The photocurable metal green blank with a gap size of 0.07 mm was immersed in the above cleaning solution, treated with an ultrasonic cleaner for 5 minutes, and then blown with an air gun to effectively remove residual slurry in the gap, resulting in a clean surface and a complete structure of the metal green blank.

[0034] Example 3

[0035] 90% of the main solvent limonene, 8% of the co-solvent ethyl acetate, 0.3% of the metal passivator hydroxyethylidene diphosphonic acid, 1.5% of the surfactant fatty alcohol polyoxyethylene ether, and 0.2% of the corrosion inhibitor sodium tungstate were mixed and ultrasonically treated to fully disperse and dissolve the mixture, resulting in a uniform and transparent photocurable metal green body cleaning solution.

[0036] The photocured metal blank with a channel length of 50 mm and a width of 0.25 mm was immersed in the above cleaning solution, treated with an ultrasonic cleaner for 5 minutes, and then blown with an air gun to thoroughly remove the residual slurry in the narrow channel, resulting in a clean metal blank with a complete structure.

[0037] Example 4

[0038] 85% of the main solvent dodecane, 13% of the co-solvent ethanol, 0.2% of the metal passivator hydroxyethylidene diphosphonic acid, 1.6% of the surfactant sorbitan ester, and 0.2% of the corrosion inhibitor sodium molybdate were mixed and ultrasonically treated to fully disperse and dissolve the mixture, resulting in a uniform and transparent light-curing metal green body cleaning solution.

[0039] The photocurable metal green blank with a pore size of 0.2 mm was immersed in the above cleaning solution, treated with an ultrasonic cleaner for 3 minutes, and then blown with an air gun to thoroughly remove the residual slurry in the pores, resulting in a clean metal green blank with a complete structure.

[0040] Example 5

[0041] A mixture of 78% tetradecane (the main solvent), 21% ethyl acetate (the co-solvent), 0.42% methylbenzotriazole (the metal passivator), 0.5% alkylphenol polyoxyethylene ether (the surfactant), and 0.08% sodium molybdate (the corrosion inhibitor) was prepared and then ultrasonically dispersed and dissolved to obtain a uniform and transparent photocurable metal green body cleaning solution.

[0042] The photocurable metal green blank with a gap size of 0.15 mm was immersed in the above cleaning solution, treated with an ultrasonic cleaner for 4 minutes, and then blown with an air gun to thoroughly remove the residual slurry in the gap, resulting in a clean surface and a complete structure of the metal green blank.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A photocured metal green compact cleaning solution, characterized by, According to the mass fraction, the cleaning solution comprises the following components: 75-90% of a main solvent, 8-25% of a cosolvent, 0.1-0.5% of a metal passivator, 0.5-2% of a surfactant, and 0.05-0.2% of an inhibitor.

2. The photocured metal green compact cleaning solution according to claim 1, characterized by: The main solvent is selected from one or more of propylene glycol methyl ether acetate, gamma-butyrolactone, limonene, dodecane, and tetradecane.

3. The photocured green metal compact cleaning solution of claim 1, wherein: The cosolvent is selected from one or more of ethanol, isopropyl alcohol, and ethyl acetate.

4. The photocured green metal compact cleaning solution of claim 1, wherein: The metal passivator is selected from one of hydroxyethylidene diphosphonic acid and methyl benzotriazole.

5. The photocured green metal compact cleaning solution of claim 1, wherein: The surfactant is selected from one or more of a silane coupling agent, a fatty alcohol polyoxyethylene ether, an alkylphenol polyoxyethylene ether, and a sorbitan ester.

6. The photocured green metal compact cleaning solution of claim 1, wherein: The inhibitor is selected from one of sodium molybdate and sodium tungstate.

7. A method for preparing a photocured metal green compact cleaning solution, characterized by: The main solvent, the cosolvent, the metal passivator, the surfactant, and the inhibitor are weighed according to the mass percentage, and the above components are added to a mixing container, and each component is fully dispersed and dissolved by ultrasonic treatment to obtain a uniform transparent photocuring metal green compact cleaning solution.

8. A cleaning method of a photocured metal green compact cleaning solution, using the photocured metal green compact cleaning solution preparation method according to claim 7, the prepared cleaning solution characterized by, The photocuring metal green compact is immersed in the cleaning solution, and the green compact is assisted in cleaning by using an ultrasonic cleaning device, and after the assisted cleaning is completed, the cleaning solution in the surface and gaps of the green compact is blown off by using an air gun, and finally the metal green compact is obtained.

9. The photocured green metal compact cleaning solution cleaning method according to claim 8, characterized by: The assisted cleaning time is 1-5 minutes.

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