A method and apparatus for processing the inner cavity of a 3D printing liquid cooling plate

Abstract

The application relates to a chemical cleaning technology and discloses a 3D printing liquid cooling plate inner cavity processing method and an inner cavity processing device, which comprises the following steps: adopting an alkaline cleaning solution to process the inner cavity of the 3D printing liquid cooling plate, activate the surface and remove metal powder and sintering debris; after the alkaline cleaning solution is removed, adopting an alkaline polishing solution to alkaline polish the inner cavity, further remove residues and flatten the surface; after the alkaline polishing solution is removed, adopting a mixed acid solution of an acid agent and a surfactant to acid bright polish the inner cavity; after the mixed acid solution is removed, adopting ash removal treatment on the inner cavity; after the ash removal liquid is removed, adopting a film forming solution to form an anticorrosion protective layer on the surface of the inner cavity; wherein the film forming solution contains fluorozirconic acid and a film forming additive; after the inner cavity is cleaned with deionized water, the inner cavity is dried. The application also discloses a use method of the inner cavity processing device. The application aims to effectively clean and polish the inner cavity of the 3D printing liquid cooling plate.

Description

Technical Field

[0001] This application relates to the field of chemical cleaning technology, and in particular to a method for treating the inner cavity of a 3D printed liquid cooling plate, an inner cavity treatment device, and a method for using the inner cavity treatment device. Background Technology

[0002] With the rapid development of power electronic products towards higher power density and miniaturization, liquid cooling technology, with its significant advantages such as high heat exchange capacity, excellent heat dissipation uniformity, and smaller footprint, is gradually replacing traditional air cooling methods. As the core heat transfer element in a liquid cooling system, the liquid cooling plate's main function is to efficiently remove heat through the circulation of internal coolant. Aluminum alloys, due to their high strength-to-weight ratio, good corrosion resistance, excellent electrical and thermal conductivity, and recyclability, have become an ideal material for manufacturing liquid cooling plates.

[0003] Because liquid cooling plates typically contain complex internal flow channels and blind holes, traditional manufacturing processes struggle to meet their forming requirements. 3D printing technology has thus become a more advantageous advanced manufacturing method. However, during the 3D printing process, these internal cavities (including blind holes) are prone to retaining metal debris, such as partially melted or sintered powder particles and loose metal powder. These residues can cause flow channel blockage, affecting the normal operation of the liquid cooling plate; even if they do not cause complete blockage, they may weaken its intended heat dissipation function. Therefore, it is essential to effectively remove internal metal debris to optimize the hydrodynamic performance of the cavities and the overall function.

[0004] Furthermore, the internal cavities formed by additive manufacturing typically have high surface roughness, making it difficult to directly meet application requirements. Although available machining methods include abrasive grinding, abrasive flow machining, internal magnetic abrasive grinding, and fluidized bed treatment, these methods are often limited in their effectiveness in reducing surface roughness and may generate new residual debris during processing, leaving it inside the cavity and requiring additional cleaning processes.

[0005] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0006] The main objective of this application is to provide a method, control device, internal cavity processing equipment, and computer-readable storage medium for processing the internal cavity of a 3D printed liquid cooling plate, aiming to achieve effective cleaning and surface polishing of the internal cavity of the 3D printed liquid cooling plate.

[0007] To achieve the above objectives, this application provides a method for processing the inner cavity of a 3D-printed liquid cooling plate, comprising the following steps: An alkaline cleaning solution is used to treat the inner cavity of the 3D printed liquid cooling plate, which activates the surface and removes metal powder and sintering debris. The alkaline cleaning solution contains sodium hydroxide, corrosion inhibitor, and complexing agent. After cleaning the inner cavity and removing the alkaline cleaning solution, an alkaline polishing solution is used to perform alkaline polishing on the inner cavity to further remove residues and smooth the surface; wherein, the alkaline polishing solution contains potassium hydroxide and / or potassium carbonate, as well as polishing additives; After cleaning the inner cavity and removing the alkaline polishing solution, the inner cavity is subjected to acidic bright polishing using a mixture of acidic agent and surfactant; wherein the acidic agent includes at least one of phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; After cleaning the inner cavity and removing the mixed acid solution, use a descaling solution to descal the inner cavity. After cleaning the inner cavity and removing the ash removal liquid, a film-forming liquid is used to form an anti-corrosion protective layer on the surface of the inner cavity; wherein, the film-forming liquid contains fluorozirconic acid and film-forming additives; After cleaning the inner cavity with deionized water, dry the inner cavity at a temperature of 100~140℃.

[0008] To achieve the above objectives, this application also provides an internal cavity processing apparatus for performing the internal cavity processing method for 3D printed liquid cooling plates as described above; the internal cavity processing apparatus includes: Water bath, chemical tank, heating plate, circulating pump, water inlet, tee connector, waste liquid collection tank; The water bath is used to hold constant temperature water and workpieces; the chemical tank has multiple sub-tanks for holding different chemicals, and each sub-tank has an independent inlet and outlet control interface. The circulating pump is installed in the pipeline between the inlet ports of the chemical tank and the water bath tank; the inlet port of the water bath tank is also connected to the water inlet via a pipeline. The three-end interfaces of the tee connector are connected to the outlet interface of the water bath, the chemical tank and the waste liquid collection tank through corresponding pipes; The heating plate acts on the areas where the water bath and chemical tank are located.

[0009] To achieve the above objectives, this application also provides a method of using an internal cavity processing device, wherein the internal cavity processing device is the internal cavity processing device described above; the method of using the internal cavity processing device includes: The 3D-printed liquid cooling plate is placed in a water bath, and the solutions in the water bath and chemical tank are heated to a preset temperature based on the heating plate; According to the processing flow of the 3D printed liquid cooling plate inner cavity treatment method, the inlet and outlet control interfaces of each chemical tank are opened in sequence, and the corresponding chemicals are introduced into the water bath tank through the circulation pump. The inner cavity of the 3D printed liquid cooling plate is subjected to alkaline activation, alkaline polishing, acid bright polishing, dust removal treatment and film protection treatment in sequence. In the alkaline activation, alkaline polishing, acidic bright polishing, dust removal, and film formation protection processes, a dynamic circulation injection method is used. The corresponding chemicals are pumped through the inner cavity channel and circulated to the corresponding tanks via a three-way connector. During the execution of each chemical treatment process, the direction of the three-way connector is from the water bath tank to the chemical tank. After each chemical treatment process is completed, room temperature clean water or deionized water is introduced through the inlet to clean the inner cavity before proceeding to the next process. During the inner cavity cleaning process, the direction of the T-connector is from the water bath to the waste liquid collection tank.

[0010] This application provides a method for treating the inner cavity of a 3D-printed liquid cooling plate, an inner cavity treatment device, and a method for using the inner cavity treatment device. It employs a step-by-step treatment method combining alkaline washing and acid washing to achieve efficient cleaning and surface polishing of the inner cavity of the 3D-printed liquid cooling plate. This solves the accessibility problem of complex inner cavities and can treat all cavity inner surfaces, including blind holes, without damage and uniformly. Secondly, the method uses a three-step chemical process of alkaline cleaning activation and polishing, followed by acidic bright polishing. This effectively removes loose and adhered residual debris while continuously reducing surface roughness, achieving efficient simultaneous cleaning and polishing and avoiding the problem of secondary residues caused by abrasive methods. Moreover, the composite process takes into account both the synergistic effect of the chemical reaction and the controllability of the process, ensuring polishing quality while reducing the risk of excessive corrosion to the substrate.

[0011] Finally, a dense anti-corrosion layer is generated in situ on the inner cavity surface, which improves the corrosion resistance and long-term reliability of the product in one step and simplifies the post-processing procedures. The entire process is environmentally friendly and controllable, providing an efficient and high-quality surface finishing solution for additive manufacturing of high-performance liquid cooling devices. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the steps of the internal cavity processing method for a 3D printed liquid cooling plate in one embodiment of this application; Figure 2 This is a schematic diagram of the structure of an internal cavity processing device according to an embodiment of this application.

[0013] Explanation of reference numerals in the attached figures: 10. Water bath; 20. Chemical tank; 30. Heating plate; 40. Circulation pump; 50. T-joint; 60. Waste liquid collection tank; 70. Water inlet; 11. Import interface; 12. Export interface; 13. Workpiece.

[0014] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0015] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0016] Furthermore, descriptions using terms such as "first" and "second" in this application are for descriptive purposes only (e.g., to distinguish identical or similar features) and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, technical solutions from different embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, such a combination should be considered nonexistent and not within the scope of protection claimed in this application.

[0017] Reference Figure 1 In one embodiment, the method for processing the inner cavity of a 3D-printed liquid cooling plate includes: Step S10: Use an alkaline cleaning solution to treat the inner cavity of the 3D printed liquid cooling plate, alkaline activation of the surface and removal of metal powder and sintering debris; wherein, the alkaline cleaning solution contains sodium hydroxide, corrosion inhibitor and complexing agent; Step S20: After cleaning the inner cavity and removing the alkaline cleaning solution, use an alkaline polishing solution to perform alkaline polishing on the inner cavity to further remove residues and smooth the surface; wherein, the alkaline polishing solution contains potassium hydroxide and / or potassium carbonate, as well as polishing additives; Step S30: After cleaning the inner cavity and removing the alkaline polishing liquid, the inner cavity is subjected to acidic bright polishing using a mixture of acidic agent and surfactant; wherein the acidic agent includes at least one of phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; Step S40: Clean the inner cavity and remove the mixed acid solution, then use a descaling solution to descal the inner cavity. Step S50: After cleaning the inner cavity and removing the ash removal liquid, a film-forming liquid is used to form an anti-corrosion protective layer on the surface of the inner cavity; wherein, the film-forming liquid contains fluorozirconic acid and film-forming additives. Step S60: After cleaning the inner cavity with deionized water, dry the inner cavity at a temperature of 100~140℃.

[0018] This embodiment provides a surface post-treatment method for the inner cavity of an additively manufactured metal liquid cooling plate. This method aims to efficiently remove printing residues, improve the surface morphology of the flow channel, and enhance its corrosion resistance. Specifically, it includes the following sequentially implemented steps: As described in step S10, firstly, an alkaline cleaning solution is prepared, comprising sodium hydroxide as the main cleaning agent, as well as a corrosion inhibitor (e.g., sodium silicate or organic amines) and a complexing agent (e.g., ethylenediaminetetraacetic acid or its sodium salt). The alkaline cleaning solution is pumped into or immersed in the inner flow channels of the 3D-printed metal liquid cooling plate, and circulated or immersed at room temperature to 50°C for 10-30 minutes. This step effectively removes incompletely sintered metal powder, oxide debris generated during sintering, and organic contaminants adhering to the flow channel surface through the saponification and emulsification effects of the alkaline solution. Simultaneously, the alkaline environment slightly activates the surface of the metal substrate (typically aluminum, copper, or stainless steel alloy), forming a hydroxylated surface (i.e., surface activation, removing some powder and metal debris), which is beneficial for subsequent processing steps.

[0019] In this way, the alkaline solution is used to selectively corrode and loosen the residual metal powder and sintering debris in the inner cavity, and to achieve surface leveling and brightening treatment.

[0020] As described in step S20, after completing step S10, the inner cavity is thoroughly rinsed with deionized water or clean water until the pH of the discharged liquid is close to neutral, to ensure complete removal of residual alkaline cleaning solution and its reaction products. Subsequently, the surface of the inner cavity is chemically and mechanically polished using an alkaline polishing solution.

[0021] Optionally, the alkaline polishing solution comprises: potassium hydroxide and / or potassium carbonate as an alkaline matrix and a mild etchant, as well as polishing additives. This alkaline polishing solution allows for control of the corrosion rate and avoids over-etching of the substrate.

[0022] Optionally, the polishing additive includes at least one of an oxidant and a metal ion chelating agent.

[0023] The alkaline polishing slurry is circulated through the inner cavity at a certain flow rate under conditions ranging from room temperature to 50°C for 5 to 15 minutes. This process further removes the micro-particles remaining in step S10 through the synergistic effect of slight chemical dissolution and mechanical grinding of the abrasive, and smooths the micro-undulations on the flow channel surface caused by uneven printing or sintering, thereby reducing surface roughness (i.e., removing residual powder and metal debris, and polishing the surface).

[0024] As described in step S30, after the treatment in step S20, the inner cavity is thoroughly cleaned again with deionized water or clean water to remove all alkaline polishing solution residues. Next, the inner cavity is treated with an acidic bright polishing solution. The polishing solution is a mixed acid solution, comprising at least one of phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid, and hydrofluoric acid as an acidic agent, and compounded with a surfactant (such as polyethylene glycol octylphenyl ether or sodium dodecyl sulfate). This mixed acid solution is circulated for 1-5 minutes at room temperature to 50°C. This step, through the selective etching of the acid and the wetting and dispersing effect of the surfactant, removes the surface oxide film or passivation layer that may be generated by alkaline polishing, achieving surface brightening and further homogenizing the microstructure, ensuring a uniform and delicate surface finish on the inner cavity.

[0025] As described in step S40, after completing the acidic bright polishing, immediately use deionized water or clean water to neutralize and rinse the inner cavity until the discharged liquid is neutral.

[0026] Optionally, the inner cavity of the liquid cooling plate can be rapidly rinsed with flowing deionized water to initially dilute and remove most of the residual mixed acid solution. Subsequently, the inner cavity is circulated and rinsed for 1 to 3 minutes at room temperature with a low-concentration alkaline neutralizing solution (e.g., a 0.5% to 2.0% sodium carbonate or sodium hydroxide solution with a pH of approximately 9 to 11) to completely neutralize any residual acidic substances and prevent them from causing continued corrosion to the workpiece or interfering with subsequent processes.

[0027] After neutralization and rinsing, the inner cavity is circulated using a special descaling solution, which can be a weakly acidic to neutral complexing cleaning solution.

[0028] Optionally, the key components of the ash removal solution include: complexing agents (such as citric acid, gluconic acid, or hydroxyethylidene diphosphonic acid, used to complex and dissolve metal ions (such as aluminum, iron, and copper ions) and convert them into soluble complexes), surfactants (fatty alcohol polyoxyethylene ethers or alkyl glycosides, used to reduce surface tension, penetrate and peel off particles attached to micro-pits), and corrosion inhibitors (benzotriazole or sodium molybdate; added in trace amounts to prevent excessive corrosion or pitting of the already glossy substrate during the ash removal process), with deionized water as the matrix.

[0029] Optionally, the complexing agent includes a primary complexing agent (citric acid or sodium gluconate) and an auxiliary complexing agent (hydroxyethylidene diphosphonic acid or aminotrimethylene phosphonic acid); the recommended ratio of the ash removal solution is: primary complexing agent 3.0% ~ 8.0%, auxiliary complexing agent 0.5% ~ 2.0%, surfactant 0.1% ~ 0.5%, corrosion inhibitor 0.05% ~ 0.3%, and the balance is deionized water (a pH adjuster may be introduced to adjust the pH to 5.0 ~ 6.5).

[0030] Optionally, the ash removal liquid is heated to 40~60°C and circulated through the inner cavity of the liquid cooling plate by pumping, with a processing time of 5~15 minutes.

[0031] In mild acidic or neutral environments, complexing agents selectively react with insoluble metal oxides / salts adhering to metal surfaces to form soluble, stable complexes, thereby detaching them from the surface. Surfactants simultaneously assist in suspending and removing loosened or dissolved contaminants, preventing their redeposition.

[0032] As described in step S50, after the ash removal process, the inner cavity is thoroughly rinsed multiple times with high-purity deionized water (conductivity <10μS / cm) until the pH value of the discharged water is stable at 6.5~7.5 and the conductivity is close to the inlet water value (e.g. ≤5μS / cm).

[0033] Subsequently, the film-forming solution is introduced into the inner cavity for chemical conversion treatment. The main components of the film-forming solution are fluorozirconic acid as the main film-forming agent and film-forming additives. This treatment is carried out at 20~40℃, and the film-forming solution is brought into contact with the activated metal surface for 1~10 minutes by pumping or immersion. During this process, fluorozirconic acid reacts with the metal substrate to form a dense inorganic-organic composite conversion film (mainly zirconium oxide / fluoride film) on the inner cavity surface. This film layer has good adhesion and can significantly improve the corrosion resistance of the inner cavity, especially its resistance to erosion by cooling media.

[0034] Optionally, the film-forming additive includes at least one of fluorotitanic acid, sodium nitrate, organic film-forming aids, and pH adjusters.

[0035] As described in step S60, the inner cavity where the conversion film has formed is finally rinsed multiple times with high-purity deionized water to thoroughly remove residual film-forming solution and free ions. The cleaning endpoint can be determined by the conductivity of the discharged water being ≤5 μS / cm. After cleaning, the liquid cooling plate is placed in a clean and dry environment and dried with hot air or vacuum at a temperature of 100~140℃ for 30~60 minutes to ensure that the inner cavity is completely dry and free of moisture residue, thereby avoiding corrosion or microbial growth during use.

[0036] Through the above sequential process, efficient and integrated post-processing of the complex internal cavity of the 3D printed liquid cooling plate is achieved, which significantly improves the surface quality, cleanliness and long-term reliability of the internal cavity.

[0037] In one embodiment, a step-by-step process combining alkaline washing and acid washing is employed to achieve efficient cleaning and surface polishing of the inner cavity of the 3D printed liquid cooling plate. This solves the accessibility problem of complex inner cavities and enables non-destructive and uniform treatment of all cavity inner surfaces, including blind holes. Secondly, the method utilizes a three-step chemical process of alkaline cleaning activation and polishing, followed by acidic bright polishing. This effectively removes loose and adhered residual debris while continuously reducing surface roughness, achieving efficient simultaneous cleaning and polishing and avoiding the problem of secondary residues caused by abrasive methods. Moreover, the composite process takes into account both the synergistic effect of chemical reactions and the controllability of the process, ensuring polishing quality while reducing the risk of excessive corrosion to the substrate.

[0038] Finally, a dense anti-corrosion layer is generated in situ on the inner cavity surface, which improves the corrosion resistance and long-term reliability of the product in one step and simplifies the post-processing procedures. The entire process is environmentally friendly and controllable, providing an efficient and high-quality surface finishing solution for additive manufacturing of high-performance liquid cooling devices.

[0039] In one embodiment, based on the above embodiments, the alkaline cleaning solution contains 10-30 g / L of sodium hydroxide, 3-8 g / L of corrosion inhibitor, and 5-15 g / L of complexing agent.

[0040] In this embodiment, a preferred embodiment of an optimized alkaline cleaning and activation step is provided for the inner cavity of a liquid-cooled plate made of aluminum alloy (such as AlSi10Mg, 6061, 7075, and other common additive manufacturing alloys). This embodiment aims to more precisely match the material properties of the aluminum alloy to maximize the control of corrosion on the substrate while achieving efficient cleaning, and to ensure the best effect of subsequent processing steps.

[0041] Optionally, the concentration of sodium hydroxide used as the main cleaning agent is preferably controlled between 10 and 30 g / L. Experiments have verified that this concentration range has a strong dissolving and peeling effect on unfused aluminum powder, Al2O3, and other sintered debris adhering to the aluminum alloy surface, effectively opening the surface oxide layer generated during the printing process and achieving alkaline activation. Concentrations below 10 g / L may result in insufficient cleaning power and incomplete removal of residues; concentrations above 30 g / L may cause over-corrosion of the substrate, leading to an unnecessary increase in surface roughness or even pitting corrosion.

[0042] Optionally, the preferred amount of corrosion inhibitor is 3 to 8 g / L. Given the high reactivity of aluminum alloys in alkaline environments, the corrosion inhibitor here needs to possess strong ability to inhibit alkaline corrosion. Sodium silicate, sodium molybdate, or their compound systems can be selected as corrosion inhibitors. These can rapidly adsorb onto the aluminum surface to form a protective silica colloidal film or passivation film, significantly slowing down the excessive erosion of the substrate by NaOH, achieving "selective cleaning"—that is, preferentially removing adhering substances rather than the substrate material, ensuring the stability of the internal cavity geometry and surface integrity.

[0043] Optionally, the preferred amount of complexing agent is 5-15 g / L. Sodium gluconate, sodium citrate, or disodium ethylenediaminetetraacetate (EDTA-2Na) is preferred. Its main functions are threefold: (1) Blocking harmful ions: Complexing cleaning solution and Al dissolved in aluminum alloy matrix 3+ Fe 3+ Cu 2+ Metal ions are removed to prevent them from forming insoluble hydroxide precipitates in an alkaline environment and re-attaching to the inner cavity surface, causing secondary pollution or affecting the uniformity of subsequent polishing.

[0044] (2) Stabilize the solution: slow down the aging of the cleaning solution caused by the accumulation of metal ions and extend its service life.

[0045] (3) Assisted cleaning: Through complexation, some insoluble contaminants are loosened and peeled off.

[0046] Optionally, the alkaline activation treatment temperature is controlled at around 50℃. This temperature range effectively accelerates the chemical reaction and dirt removal process of alkaline cleaning, while avoiding excessive temperature that could lead to the failure of corrosion inhibitors or excessive evaporation of the solution. The preferred treatment time is 15 to 25 minutes, and a circulating pump can be used to ensure that the cleaning solution flows and exchanges fully within the complex flow channels.

[0047] This effectively removes over 99% of loose metal powder, sintered slag, and organic contaminants from the inner cavity surface. Simultaneously, under the protection of the corrosion inhibitor, uniform, mild etching of the aluminum alloy substrate surface is achieved, generating an active surface rich in hydroxyl groups (-OH). This activated surface has higher surface energy, greatly promoting the contact and reaction between the polishing solution or conversion film and the substrate in subsequent steps, improving the consistency of the treatment and the adhesion of the film.

[0048] In one embodiment, based on the above embodiments, the polishing additive includes at least one of an oxidant and a metal ion chelating agent.

[0049] Optionally, the alkaline polishing solution contains 30-80 g / L of potassium hydroxide, 10-30 g / L of potassium carbonate, 5-15 g / L of oxidant, and 5-10 g / L of metal ion chelating agent.

[0050] In this embodiment, the aim is to achieve better micro-removal, smoothing and pretreatment effects on the surface of the aluminum alloy inner cavity, laying a more ideal foundation for subsequent bright polishing and anti-corrosion film formation.

[0051] Optionally, an oxidant of 5-15 g / L is preferably added to the alkaline polishing solution, specifically hydrogen peroxide, ammonium persulfate, or potassium permanganate. Its main function is that, under alkaline conditions, the oxidant rapidly forms an extremely thin, uniform, and easily soluble alumina transition layer on the aluminum alloy surface. This process achieves selective oxidation and dissolution of surface protrusions, thereby accelerating micro-leveling and promoting surface brightening. Simultaneously, it helps suppress selective corrosion caused by microscopic electrochemical differences due to grain orientation within the aluminum alloy or printing, resulting in a more consistent material removal rate across the entire inner cavity surface.

[0052] Optionally, a chelating agent of 5-10 g / L is preferably added, specifically sodium gluconate, potassium sodium tartrate, or aminotrimethylenephosphonic acid. Its core function is to chelate the Al dissolved from the aluminum alloy matrix during the real-time polishing process. 3+ Plasma is used to prevent the formation of hydroxide gels or precipitates (such as Al(OH)3 colloids) under alkaline conditions. If these precipitates adhere to the surface or act as abrasives, they can lead to uneven polishing, scratches, or haze. At the same time, it maintains a low concentration of free metal ions in the polishing solution to prevent the solution from aging rapidly and deteriorating in performance due to ion accumulation, thus ensuring the stability and repeatability of the polishing effect. In addition, some chelating agents (such as tartrates) can form soluble complexes with aluminum ions, which can slightly promote the dissolution of micro-protrusions and assist in leveling.

[0053] Optionally, the concentration of potassium hydroxide is preferably 30-80 g / L, as it serves as the main alkaline provider and chemical solvent, and the KOH concentration within this range can provide sufficient OH-. - Ions are used to effectively dissolve the alumina transition layer formed by the oxidant and the aluminum alloy itself, achieving controlled chemical removal. If the concentration is too low, the polishing rate will be slow and the efficiency will be low; if it is too high, the removal rate may be too fast, making it difficult to control the surface morphology, and even causing over-corrosion.

[0054] Optionally, the concentration of potassium carbonate is preferably 10-30 g / L. The buffering system of potassium carbonate helps stabilize the pH of the polishing solution, keeping it relatively constant during treatment, thereby ensuring the stability of the polishing rate; CO3 2- Ions have a certain weak corrosive and cleaning effect on the surface, and their presence helps to improve the rheological properties of the polishing fluid, giving it good fluidity and wettability in complex cavities.

[0055] Optionally, the alkaline polishing treatment temperature is controlled at 35~45℃. This gentle temperature rise can accelerate the chemical reaction of oxidation and dissolution, improve polishing efficiency, and at the same time avoid excessive temperature causing the oxidant to decompose too quickly or the solution to evaporate excessively; the treatment time is preferably 8~15 minutes.

[0056] In this way, with the synergistic effect of oxidants and chelating agents, the micro-roughness caused by 3D printing textures and sintered particle adhesion can be reduced more effectively, resulting in a more uniform and smooth surface. At the same time, any trace contaminants that may remain in step S10 can be effectively removed, and a fresh, uniform, and highly reactive hydroxyl-rich aluminum surface can be formed. This surface is extremely beneficial for the uniform reaction of subsequent acidic bright polishing and the dense adhesion of the final anti-corrosion conversion film.

[0057] In one embodiment, based on the above embodiments, the mixed acid solution comprises: 40% ~ 60% phosphoric acid; 10% ~ 20% sulfuric acid; 3% ~ 8% nitric acid; 0.5% ~ 2% surfactant; The remainder is deionized water.

[0058] In this embodiment, the acidic bright polishing slurry used for the aluminum alloy inner cavity is a functional mixed acid slurry with phosphoric acid as the main component and a variety of inorganic acids. Its volume percentage (v / v) composition is optimized as follows: Optionally, the phosphoric acid content is 40% to 60%, used as the main acid. Phosphoric acid has a moderate dissolving ability for aluminum alloys, and its anion (PO4) 3- This process can form an extremely thin aluminum phosphate conversion layer on the aluminum surface. It preferentially dissolves microscopic protrusions, resulting in significant leveling and brightening effects. Simultaneously, the high viscosity of phosphoric acid helps form a uniform liquid film on vertical or complex internal cavity walls, ensuring the uniformity of the treatment.

[0059] Optionally, the sulfuric acid content is 10% to 20%, which serves to provide strongly ionized H+. + and SO4 2- This significantly improves the overall activity and conductivity of the acid solution, accelerating the initial activation and uniform etching of the aluminum substrate, and preventing the reaction from being too mild and uneven due to the action of phosphoric acid alone. The addition of sulfuric acid helps to achieve a faster polishing rate and a brighter surface.

[0060] Optionally, the nitric acid content is 3% to 8%. As a strong oxidizing agent, it can rapidly oxidize the aluminum surface, forming a dense passivation film of aluminum oxide. At the same time, the gaseous escape process of its reduction products (nitrogen oxides) has a micro-stirring and cleaning effect on the surface. The oxidizing effect of nitric acid can inhibit hydrogen evolution corrosion of the substrate by the acid solution (reducing the risk of hydrogen embrittlement), making the dissolution process more uniform, thereby producing a smooth, mirror-like surface.

[0061] Optionally, the surfactant content is 0.5% to 2%. Preferred types are nonionic surfactants (such as fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers) or special fluorinated surfactants. Surfactants can significantly improve the wettability and spreadability of acid in complex cavities, especially microchannels, ensuring complete acid coverage of all surfaces without dead zones. Simultaneously, they form a thin film at the liquid-gas interface, effectively reducing the volatilization of irritating acid mist during polishing and improving the working environment. They also help hydrogen bubbles and dissolution products generated during the reaction to quickly detach from the metal surface, preventing their adhesion and resulting pitting corrosion or uneven polishing.

[0062] The remaining volume of the mixed acid solution is deionized water, used to adjust the acid solution to the working concentration and as a medium to ensure uniform mixing of all components. Using deionized water avoids the introduction of impurity ions (such as Cl-). - Ca 2+ Mg 2+ It can interfere with the polishing process or contaminate the surface.

[0063] In this formulation, sulfuric acid rapidly and uniformly activates and initially dissolves the surface; phosphoric acid, while dissolving, simultaneously performs micro-leveling and forms a transitional conversion film; nitric acid, as an oxidant, inhibits localized over-corrosion by promoting uniform surface passivation and generates an optically smooth, extremely thin oxide layer. After treatment, the aluminum alloy inner cavity surface exhibits a uniform silvery-white to bright metallic luster, with a significantly reduced micro-roughness (Ra) and a clean, dust-free surface. This fresh, clean surface, with its specific chemical state, is highly conducive to the uniform, dense growth and high-adhesion bonding of the fluorozirconic acid conversion film in subsequent steps.

[0064] In one embodiment, based on the above embodiments, the film-forming additive includes at least one of fluorotitanic acid, sodium nitrate, organic film-forming aids, and pH adjusters.

[0065] Optionally, the film-forming solution contains 0.5 to 2.0 g / L of fluorozirconic acid, 0.1 to 0.5 g / L of fluorotitanic acid, 0.5 to 2.0 g / L of sodium nitrate, and 1.0 to 5.0 g / L of organic film-forming aids.

[0066] In this embodiment, an optimized film-forming liquid formulation is provided for the aluminum alloy inner cavity. This formulation aims to construct an ultra-thin, dense, highly adhesive, and corrosion-resistant chromium-free conversion film on the polished, bright aluminum alloy inner cavity surface, while also ensuring compatibility with subsequent coating / bonding.

[0067] The film-forming solution is a composite system based on fluorozirconate, synergistically enhanced by the introduction of various functional additives. Its recommended working concentration ratio is optimized as follows: Optionally, fluorozirconic acid (H₂ZrF₆, calculated as Zr) at a content of 0.5 ~ 2.0 g / L is used as the main film-forming agent. The ZrF₆ in the solution... 2- or Zr 4+ Ions react with active sites (such as Al-OH) on the aluminum surface after pre-acid polishing to form a nanoscale-thick amorphous zirconium oxide / zirconium fluoride composite conversion film (ZrO2 / ZrFx) on the aluminum substrate. This film has excellent chemical inertness and physical barrier properties, and is the main source of corrosion resistance.

[0068] Optionally, fluorotitanic acid (H₂TiF₆, calculated as Ti) content is 0.1 ~ 0.5 g / L, serving as a synergistic film-forming agent and performance enhancer. Among them, titanium ions (Ti 4+ The introduction of titanium promotes finer and more uniform nucleation, forming a Zr-Ti-O composite oxide with the zirconium film, resulting in a denser film structure. Titanium oxide is also stable, and the composite film provides more effective resistance to pitting corrosion. This contributes to a more uniform film color (typically a light blue interference color or maintaining the metallic color) and enhances the chemical adhesion to subsequent organic coatings (such as paints and adhesives).

[0069] Optionally, sodium nitrate can be present at a concentration of 0.5 to 2.0 g / L, acting as an oxidation promoter and pH buffer. NO3 - As a mild oxidizing agent, it can slightly oxidize the alumina matrix, increasing the surface hydroxyl (-OH) density and providing more active sites for zirconium / titanium deposition, thereby accelerating the film formation reaction and improving film weight and coverage. Sodium nitrate has a certain buffering capacity, which helps to reduce the consumption of F in the film formation reaction. - and H + This helps to reduce fluctuations in the pH of the working solution and improve process stability.

[0070] Optionally, the content of the organic film-forming aid is 1.0 ~ 5.0 g / L. Preferred types are water-soluble polymers, such as polyacrylic acid, polyvinyl alcohol, modified silane coupling agents, or specific nitrogen-containing organic compounds. The organic molecules in the organic film-forming aid can adsorb onto the metal surface or coordinate with inorganic Zr / Ti ions, partially integrating into the conversion membrane, filling the micropores of the inorganic membrane, achieving a "pore-sealing" effect, and significantly improving the membrane's density and corrosion resistance. Simultaneously, the organic film-forming aid can introduce organic functional groups onto the conversion membrane surface, greatly improving the wettability and chemical bonding with subsequent organic coatings (paints, adhesives), and enhancing adhesion. Furthermore, the organic film-forming aid can reduce the surface tension of the treatment liquid, ensuring complete wetting of all surfaces in complex internal cavities and promoting uniform film-forming reactions.

[0071] Optionally, a pH adjuster is used to precisely adjust and maintain the working pH of the film-forming solution at 3.8–4.5 (optimal range 4.0–4.3). The pH adjuster can be used for fine adjustment with ammonia or dilute nitric acid.

[0072] Optionally, the recommended temperature for film-forming protective treatment is 25~35℃ (room temperature or slight heating). This temperature range ensures a sufficient reaction rate while avoiding runaway reaction or inactivation of organic additives due to excessive temperature; the preferred treatment time is 3~8 minutes.

[0073] In this way, fluorozirconic acid / fluorotitanic acid provides a corrosion-resistant inorganic framework, sodium nitrate activates the surface and stabilizes the reaction environment through oxidation, and organic film-forming aids are interspersed within the inorganic network to achieve physical sealing and chemical modification. The synergistic effect of these three components results in a dense, ultrathin (50-200 nm) hybrid layer with excellent chemical stability and physical bonding.

[0074] The aluminum alloy inner cavity treated in this way can easily pass the neutral salt spray test for tens to hundreds of hours without substrate corrosion, meeting the stringent requirements for long-term use. The film surface is rich in organic functional groups, providing an ideal substrate for subsequent possible sealing, welding or coating, ensuring strong adhesion, and is completely free of toxic substances such as hexavalent chromium.

[0075] In addition, refer to Figure 2 This application also provides an internal cavity processing device for performing the internal cavity processing method for 3D printed liquid cooling plates as described in the above embodiments; the internal cavity processing device includes: 10 water bath tank, 20 chemical tank, 30 heating plate, 40 circulating pump, 70 water inlet, 50 tee connector, 60 waste liquid collection tank; The water bath 10 is used to hold constant temperature water and workpiece 13; the chemical tank 20 is provided with multiple sub-tanks (not shown in the figure) for holding different chemicals, and each sub-tank has an independent inlet and outlet control interface. The circulating pump 40 is installed in the pipeline between the inlet interface 11 of the chemical tank 20 and the water bath 10; the inlet interface 11 of the water bath 10 is also connected to the water inlet 70 through a pipeline. The three-end interfaces of the tee connector 50 are connected to the outlet interface 12 of the water bath 10, the chemical tank 20 and the waste liquid collection tank 60 through corresponding pipes. The heating plate 30 acts on the area where the water bath 10 and the chemical tank 20 are located.

[0076] In this embodiment, to efficiently, accurately, and automatically execute the aforementioned processing steps S10 to S50, an integrated cavity processing device is proposed. This device, through a modular tank, a precise temperature control system, a programmable fluid circulation path, and a waste liquid collection unit, enables sequential chemical processing of the cavities of one or more liquid-cooled plate workpieces, ensuring the stability and controllability of parameters (temperature, time, flow rate) for each process step, and effectively separating waste liquids of different properties.

[0077] The internal cavity processing equipment mainly includes the following core components, and their connection relationship and functional coordination are as follows: 1. Water bath 10 The water bath 10 serves as the core cavity for supporting and temperature-controlled treatment of the workpiece 13. It is constructed as a rectangular or cylindrical container with good thermal insulation properties, and its internal volume is designed to accommodate one or more workpieces 13 to be processed (i.e., liquid-cooled plates) and a sufficient amount of temperature-controlled carrier liquid (usually deionized water). The shell of the water bath 10 is preferably made of corrosion-resistant materials (such as polypropylene or stainless steel lined with plastic).

[0078] Optionally, the water bath 10 heats and controls the temperature of the carrier liquid inside it through an external heat exchange system (such as the heating plate 30 described below), so that the overall temperature of the workpiece 13 immersed in it is uniformly and stably maintained at the preset process temperature (e.g., room temperature to 50°C), providing a precise thermal environment for each chemical treatment step.

[0079] Optionally, the water bath 10 is provided with at least two key interfaces: an inlet interface 11 and an outlet interface 12. The inlet interface 11 is used to receive the treatment fluid flow from the chemical supply system or the cleaning water system; the outlet interface 12 is used to discharge the liquid that has flowed through the inner cavity of the workpiece 13.

[0080] 2. Chemical tank 20 The chemical tank 20 is an integrated multi-compartment container used for storing and processing various chemical working solutions required in the process. Its interior is divided into multiple independent compartments by partitions, for example: Sub-tank 1: Used to hold alkaline cleaning solution; Second compartment: Used to hold alkaline polishing liquid; Sub-tank 3: Used to hold mixed acid solution; Sub-tank 4: Used to hold ash removal liquid; Fifth compartment: Used to hold the film-forming solution.

[0081] Each tank is equipped with an independent inlet / outlet control interface, which can be controlled by a corrosion-resistant solenoid valve or a pneumatic diaphragm valve, and can be connected to a level sensor. This design allows the equipment control unit to precisely select which chemicals to pump into the treatment cycle as needed, while avoiding cross-contamination between different chemicals.

[0082] 3. Fluid drive and path control unit This unit is responsible for processing the flow of liquid within the system, and its core components include a circulation pump 40, a piping network, and a path switching device.

[0083] Circulation pump 40: One or more chemically resistant, magnetically driven circulation pumps 40 or diaphragm pumps. Their critical installation location is in the connecting pipe between the outlets of each compartment of the chemical tank 20 and the inlet interface 11 of the water bath 10. This pump provides sufficient pressure and flow to pump the selected chemicals from the storage compartments and propel them through the complex internal cavity of the liquid-cooled plate workpiece in the water bath 10, ensuring sufficient contact between the treatment fluid and the cavity surface for a chemical reaction.

[0084] Inlet 70: An inlet connected to the high-pressure deionized water supply system. It is connected in parallel to the pipeline section before the inlet port 11 of the water bath 10. During the cleaning process, the control unit closes the chemical supply valve and opens the inlet valve, allowing clean water or deionized water to directly enter the inlet of the water bath 10 to powerfully rinse the inner cavity of the workpiece 13.

[0085] Path switching device: a tee connector 50 and its network, implemented by a single tee connector 50 (T-type or Y-type); more complex systems may use multi-way valve assemblies. The three ports of this tee connector 50 are connected to corresponding pipes: Port A: Outlet interface 12 of water bath 10, which receives the processed liquid flowing out of the inner cavity of workpiece 13.

[0086] Port B: Chemical Tank 20 (specifically, the recovery interface for the currently used sub-tank). In process stages where the processing fluid needs to be recycled (such as extending polishing time), the liquid can return to the original sub-tank via this path.

[0087] Port C: Waste liquid collection tank 60. During the drainage phase after each processing step, or in the cleaning process, waste liquid is directed via a valve to flow into the designated waste liquid collection tank 60. The waste liquid collection tank 60 can be further divided to collect waste liquids of different acidity or alkalinity for subsequent environmental treatment.

[0088] 4. Heating plate 30 The heating plate 30 is the temperature maintenance device of the equipment. Its effective area covers the bottom or sidewall areas of the water bath 10 and the chemical tank 20. The heating plate 30 is preferably an electric heating plate or a jacketed heat transfer oil heating plate using a PID (proportional-integral-derivative) control algorithm, and is equipped with a high-precision thermocouple temperature sensor. Its functions include: The carrier water in the water bath 10 is heated and kept at a constant temperature to provide a stable processing temperature for the workpiece 13. Temperature control is applied to specific sub-tanks of the chemical tank 20 (such as alkaline cleaning tanks and alkaline polishing tanks that require heating) to maintain the optimal active temperature of the working fluid. 5. Control unit (not shown in the diagram) The equipment is equipped with a programmable logic controller (PLC) or industrial computer control system. This system is electrically connected to all valves, pumps, heating plates 30, temperature sensors, and level sensors. Through a preset program, the control system automatically executes the following sequence: (1) Step selection: According to the process formula, open the outlet valve of the corresponding chemical tank.

[0089] (2) Temperature control: Start the heating plate 30 to make the water bath 10 and the corresponding chemical tank reach the set temperature.

[0090] (3) Processing cycle: Start the circulation pump 40 to pump the chemicals into the inner cavity of the workpiece 13 for timed circulation processing.

[0091] (4) Drainage and switching: Close the chemical valve, switch the three-way connector 50 to the waste liquid collection tank 60 path, and drain the pipeline and residual liquid in the inner cavity.

[0092] (5) Cleaning process: switch the three-way valve to the waste liquid collection tank 60, open the water inlet valve 70, and perform multiple deionized water rinsing.

[0093] (6) Step iteration: Repeat the above process to complete alkaline cleaning, alkaline polishing, acidic bright polishing, film protection treatment and final cleaning in sequence.

[0094] (7) Safety monitoring: Monitor temperature, pressure and liquid level abnormalities, and have an emergency stop function.

[0095] Brief description of the working process of the internal cavity treatment equipment (taking the S10 alkaline activation step as an example): The controller activates the heating plate 30 of the water bath 10 and the alkaline cleaning solution tank, raising the temperature to 50°C; The controller opens the valve connected to the alkaline cleaning tank and simultaneously switches the tee connector 50 to the circuit (port B) connected to that tank. Start the circulation pump 40, and the alkaline cleaning solution is pumped into the inlet of the water bath 10, flows through the inner cavity of the liquid cooling plate submerged in water, and returns to the cleaning solution distribution tank from the outlet through the three-way connector 50, forming a closed loop, which continues for a set time (e.g., 20 minutes). When the time is up, the controller closes the cleaning fluid valve, switches the three-way valve to the waste liquid collection tank 60 (port C), and the pump discharges most of the waste liquid from the pipeline and inner cavity into the waste liquid tank; Switch the controller to the three-way valve to the waste liquid collection tank 60, open the deionized water inlet valve, perform multiple rinsing, and discharge the rinsing wastewater directly into the waste liquid tank; The subsequent S20, S30, S40, and S50 steps are performed automatically in sequence. The controller only needs to switch between different chemical tanks and adjust the temperature and time parameters.

[0096] The cavity processing equipment provided in this embodiment, through its integrated and automated design, achieves precise, reliable, and highly repeatable execution of multi-step chemical processing of the cavity of a 3D-printed liquid-cooled plate. The integrated equipment completes the entire process from cleaning and polishing to film formation; temperature, time, and fluid path are precisely controlled by a program to ensure consistent processing quality; closed-loop circulation and automatic waste liquid classification and collection reduce the risk of operator exposure to chemicals and facilitate waste liquid management; automated operation reduces manual intervention and is suitable for batch processing.

[0097] In one embodiment, based on the above embodiments, both the water bath 10 and the chemical tank 20 are equipped with functional sensors, including at least one of a temperature sensor, a pressure sensor, and a flow sensor; The temperature sensor is used in conjunction with the heating plate 30 to control the solution temperature. The pressure sensor is used in conjunction with the circulating pump 40 to control the internal pressure; The flow sensor is used in conjunction with the circulating pump 40 to control the solution flow rate.

[0098] In this embodiment, in order to achieve higher precision control of the aforementioned internal cavity processing process, real-time monitoring of process status, and digital traceability of process quality, a multi-functional sensor system is integrated into the key processing unit of the internal cavity processing equipment.

[0099] The functional sensor system mainly includes three types: temperature sensors, pressure sensors, and flow sensors, and is strategically deployed at key nodes of the water bath 10 and the chemical tank 20.

[0100] Optionally, the water bath 10 is provided with at least one temperature sensor (such as a PT100 platinum resistance thermometer or a K-type thermocouple), whose probe is directly immersed in the carrier liquid of the water bath 10, preferably located in the middle of the tank and away from the direct water inlet / heating point, in order to measure the actual core temperature of the liquid surrounding the workpiece 13.

[0101] Optionally, a temperature sensor can be independently deployed inside each chemical tank requiring temperature control (such as an alkaline cleaning tank or an alkaline polishing tank) to monitor the real-time temperature of the working chemical solution.

[0102] Optionally, all temperature sensors are connected to the central control unit of the device via signal connection.

[0103] The control unit presets target temperature values ​​for each process step (e.g., 50℃±1℃ for the alkaline cleaning step). The control unit compares the measured values ​​fed back by the temperature sensor with the target values ​​in real time, and generates control signals based on the PID (proportional-integral-derivative) algorithm, which are then output to the power regulation module of the heating plate 30.

[0104] Through this closed-loop feedback, the output power of the heating plate 30 is dynamically adjusted (e.g., increasing power for rapid heating, or decreasing power to prevent overshoot), ensuring that the carrier liquid in the water bath 10 and the working solutions of various chemicals remain within a strictly set temperature range throughout the entire processing cycle. This overcomes the fluctuations caused by relying solely on heating time or ambient temperature, which is particularly crucial for the polishing and film-forming steps, which are critical to the chemical reaction rate.

[0105] Optionally, a pressure sensor (such as a piezoresistive or ceramic capacitive pressure transmitter) may be installed on the main circulation pipeline near the inlet port 11 of the water bath 10 and / or at the outlet of the circulation pump 40. This pressure sensor is used to monitor the system pressure pumped into the liquid cooling plate cavity and throughout the entire circulation pipeline in real time.

[0106] The pressure sensor signal is transmitted to the central control unit in real time. The control unit is set with a safe pressure upper limit (e.g., 0.5 MPa, to prevent excessive pressure from damaging the workpiece 13 or pipeline) and a process pressure window (e.g., 0.1~0.3 MPa, to ensure that the liquid can effectively flow into the micro channel).

[0107] Optionally, when the pressure sensor feedback value exceeds the safety limit, the control unit immediately sends a stop or speed reduction command to the circulating pump 40 and triggers an audible and visual alarm to prevent damage to the equipment and workpiece 13. The control unit can actively maintain the system pressure within the optimal process window by adjusting the motor speed of the circulating pump 40 via a frequency converter according to a preset process pressure curve. For example, higher pressure is needed in the initial processing stage to flush away loose debris, while a stable medium pressure needs to be maintained during the fine polishing stage.

[0108] Optionally, a flow sensor (such as an electromagnetic flow meter or a turbine flow meter) may be installed on the main delivery pipeline between the outlet of the circulating pump 40 and the inlet of the water bath 10. This flow sensor is used to accurately measure the volumetric flow rate of the processed liquid flowing through the inner cavity of the liquid cooling plate per unit time.

[0109] The flow sensor sends a continuous flow signal to the central control unit. The control unit is preset with target flow values ​​or flow ranges required for different processing steps (e.g., high flow is required for intensive cleaning, while low and stable flow is required for film-forming protection).

[0110] Optionally, the control unit compares the flow feedback value with the target value and adjusts the rotational speed of the circulating pump 40 (frequency conversion control) to achieve precise and stable control of the pipeline flow. This ensures the consistency of the hydrodynamic conditions of the interaction between the chemical reagent and the inner cavity surface.

[0111] By combining flow rate data with time, the total circulation volume can be calculated and compared with the theoretical volume of the internal cavity to determine whether the cavity is unobstructed or whether there is a serious blockage. All flow rate data is recorded and stored, providing a traceable process parameter file for the processing of each workpiece 13.

[0112] The three sensing and control subsystems mentioned above can be integrated, managed, and optimized collaboratively by the central control unit. Example scenario (starting the alkaline polishing step): The control unit issues a command to open the alkaline polishing liquid distribution valve and start the circulation pump 40.

[0113] The flow sensor reports an increase in flow rate, and the control unit adjusts the pump speed until the preset polishing flow rate is reached.

[0114] The pressure sensor simultaneously monitors the system pressure to ensure that the pressure does not exceed the limit while the flow rate meets the standard; if the pressure rises abnormally due to narrow flow channels, the system can automatically fine-tune the flow rate setting to protect the equipment.

[0115] Temperature sensors (water bath 10 and polishing liquid bath) monitor the temperature, and the control unit drives the heating plate 30 to work, so that the system can quickly heat up and stabilize at the temperature point required by the polishing process.

[0116] Throughout the process, all sensor data is recorded and displayed in real time, and can be stored in conjunction with the process formula.

[0117] In one embodiment, by integrating multifunctional sensors and forming an intelligent closed loop with the actuator, real-time feedback control of temperature, pressure, and flow eliminates external interference, ensuring high consistency of internal processing environment parameters for each batch and each workpiece 13, significantly improving product yield. Furthermore, real-time monitoring of pressure and flow can prevent malfunctions such as pipe bursts, dry runs, and overloads, enabling predictive maintenance. All key process parameters are fully recorded in data form, providing a solid data foundation for quality analysis, process optimization, and problem tracing. The equipment can adaptively adjust based on sensor feedback, reducing reliance on operator experience and making the automated execution of complex processes more reliable.

[0118] Furthermore, this application embodiment also provides a method for using an internal cavity processing device, wherein the internal cavity processing device is the internal cavity processing device as described in the above embodiments; the method for using the internal cavity processing device includes: The 3D-printed liquid cooling plate is placed in a water bath, and the solutions in the water bath and chemical tank are heated to a preset temperature based on the heating plate; According to the processing flow of the 3D printed liquid cooling plate inner cavity treatment method, the inlet and outlet control interfaces of each chemical tank are opened in sequence, and the corresponding chemicals are introduced into the water bath tank through the circulation pump. The inner cavity of the 3D printed liquid cooling plate is subjected to alkaline activation, alkaline polishing, acid bright polishing, dust removal treatment and film protection treatment in sequence. In the alkaline activation, alkaline polishing, acidic bright polishing, dust removal, and film formation protection processes, a dynamic circulation injection method is used. The corresponding chemicals are pumped through the inner cavity channel and circulated to the corresponding tanks via a three-way connector. During the execution of each chemical treatment process, the direction of the three-way connector is from the water bath tank to the chemical tank. After each chemical treatment process is completed, room temperature clean water or deionized water is introduced through the inlet to clean the inner cavity before proceeding to the next process. During the inner cavity cleaning process, the direction of the T-connector is from the water bath to the waste liquid collection tank.

[0119] In this embodiment, the aforementioned internal cavity processing equipment is used to perform surface treatment on the complex flow channels inside the liquid cooling plate of metal (such as aluminum alloy, copper, stainless steel) manufactured by 3D printing (such as SLM selective laser melting) to remove printing residues, improve surface smoothness, and enhance corrosion resistance.

[0120] First, the 3D-printed liquid-cooled plate, which has been printed and preliminarily cleaned (e.g., by blowing air), is securely immersed and fixed in the carrier liquid in a water bath using a special fixture or bracket. Ensure the workpiece is completely submerged and positioned to facilitate the removal of air bubbles from the flow channels.

[0121] Optionally, quick-connect fittings can be used to reliably seal the inlet and outlet of the liquid cooling plate to the corresponding interfaces on the main circulation pipeline of the equipment (leading out through the inlet and outlet control interfaces of the water bath). This is a crucial step to ensure the effective operation of subsequent circulation treatment.

[0122] Optionally, on the central control panel, the target temperature required for all processes to be executed (alkaline activation, alkaline polishing, acidic bright polishing, dust removal, and film protection) can be set according to the preset process formula.

[0123] The heating plates are activated (for the water bath and any necessary chemical tanks). Based on feedback from the temperature sensors, the system uses closed-loop control to heat and precisely maintain the carrier liquid in the water bath and the working liquid in each chemical tank at their respective preset process temperatures. (Sensor function: Ensures accurate reaction initiation temperature, avoiding uneven processing or poor results due to temperature differences.) When performing alkaline activation-related processes, the system automatically performs the following actions: Switch the tee or valve connecting the water bath and the alkaline activation solution tank to the "water bath -- alkaline activation solution tank" circulation direction; open the inlet and outlet control interface valve of the alkaline activation solution tank; start the circulation pump, which pumps the alkaline activation working solution out of the chemical tank and into the inner cavity of the liquid cooling plate. After flowing through all the complex flow channels, it mixes with the oxides and some residues dissolved from the surface of the workpiece, and returns to the alkaline activation solution tank through the outlet pipe and tee, forming a closed loop.

[0124] Optionally, based on real-time flow monitoring by a flow sensor, the control unit adjusts the speed of the circulating pump to stabilize the flow rate at the optimal value set by the process (e.g., 5~10 L / min), ensuring that the activation solution is in full contact with the inner cavity surface.

[0125] Optionally, the system pressure is monitored in real time based on a pressure sensor to ensure it remains within a safe range (e.g., 0.1-0.3 MPa). If the pressure is too high, the pump speed is automatically adjusted to prevent damage to the workpiece or pipeline.

[0126] Optionally, based on a temperature sensor, the temperature of the water bath and activation solution is continuously monitored, and a constant temperature (such as room temperature to 50°C) is maintained by a heating plate to ensure a stable chemical reaction rate.

[0127] This dynamic circulation process continues for a preset time (e.g., 10-30 minutes). After the timer ends, the system automatically stops the circulation pump, closes the valve of the alkaline activation solution tank, and switches the T-connector to the "water bath - waste liquid collection tank" direction.

[0128] A large volume of room temperature clean water or deionized water is pumped into the system through the equipment inlet to powerfully flush the inner cavity of the liquid cooling plate. After flowing through the inner cavity, the flushing fluid is directly discharged into the waste liquid collection tank, without returning to any chemical tank, ensuring that any residual alkaline activation solution is completely removed. The flushing time continues until the pH value of the discharged liquid is close to neutral. After flushing is completed, the system is ready to switch to the next process.

[0129] During the alkaline polishing process, the above-described dynamic chemical injection operation is repeated, but the chemicals are switched to an alkaline polishing solution. After the treatment, a thorough water rinse is performed, switching to the waste liquid direction.

[0130] During the acidic bright polishing process, repeat the above dynamic chemical injection operation, but switch the chemicals to a mixed acid solution. After the treatment, perform a thorough water rinse to ensure all acid residue is removed.

[0131] During the ash removal process, repeat the above-described dynamic chemical injection operation, but switch the chemicals to a ash removal liquid. After treatment, perform a thorough water rinse to remove all residues.

[0132] During the film-forming and protective treatment, the above-described dynamic cyclic chemical injection operation is repeated, but the chemicals are switched to a film-forming solution. After the treatment, a final deionized water rinse is performed to remove excess film-forming solution from the surface.

[0133] After all chemical processes are completed, a final fine rinse can be performed using high-purity deionized water.

[0134] Remove the liquid cooling plate from the water bath and disconnect the piping. Residual moisture in the internal cavity can be dried using compressed air, hot air, or by placing it in a clean oven.

[0135] In this way, only one clamping and formulation start-up are required, and all subsequent switching, circulation, rinsing, and temperature control are completed automatically by the equipment, greatly reducing human error. At the same time, it ensures full and uniform contact between the chemicals and every corner of the inner cavity; moreover, the closed-loop circulation greatly reduces chemical consumption and waste liquid generation; and the staged water washing and directional collection of waste liquid facilitate subsequent treatment.

[0136] In summary, the cavity treatment method, cavity treatment equipment, and usage method of the cavity treatment equipment provided in this application embodiment employ a step-by-step treatment method combining alkaline washing and acid washing to achieve efficient cleaning and surface polishing of the cavity of the 3D printed liquid cooling plate. This solves the accessibility problem of complex cavities and can treat all cavity surfaces, including blind holes, without damage and uniformly. Secondly, the method uses a three-step chemical action of alkaline cleaning activation and polishing, followed by acidic bright polishing to effectively remove loose and adhered residual debris while continuously reducing surface roughness. This achieves efficient simultaneous cleaning and polishing, avoiding the problem of secondary residues caused by abrasive methods. Moreover, the composite process takes into account both the synergistic effect of chemical reactions and the controllability of the process, ensuring polishing quality while reducing the risk of excessive corrosion to the substrate.

[0137] Finally, a dense anti-corrosion layer is generated in situ on the inner cavity surface, which improves the corrosion resistance and long-term reliability of the product in one step and simplifies the post-processing procedures. The entire process is environmentally friendly and controllable, providing an efficient and high-quality surface finishing solution for additive manufacturing of high-performance liquid cooling devices.

[0138] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media provided in this application and in the embodiments may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual-speed SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0139] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0140] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural changes made based on the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for processing the inner cavity of a 3D-printed liquid-cooled plate, characterized in that, include: An alkaline cleaning solution is used to treat the inner cavity of the 3D printed liquid cooling plate, which activates the surface and removes metal powder and sintering debris. The alkaline cleaning solution contains sodium hydroxide, corrosion inhibitor, and complexing agent. After cleaning the inner cavity and removing the alkaline cleaning solution, an alkaline polishing solution is used to perform alkaline polishing on the inner cavity to further remove residues and smooth the surface; wherein, the alkaline polishing solution contains potassium hydroxide and / or potassium carbonate, as well as polishing additives; After cleaning the inner cavity and removing the alkaline polishing solution, the inner cavity is subjected to acidic bright polishing using a mixture of acidic agent and surfactant; wherein the acidic agent includes at least one of phosphoric acid, sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; After cleaning the inner cavity and removing the mixed acid solution, use a descaling solution to descal the inner cavity. After cleaning the inner cavity and removing the ash removal liquid, a film-forming liquid is used to form an anti-corrosion protective layer on the surface of the inner cavity; wherein, the film-forming liquid contains fluorozirconic acid and film-forming additives; After cleaning the inner cavity with deionized water, dry the inner cavity at a temperature of 100~140℃.

2. The method for processing the inner cavity of a 3D-printed liquid-cooled plate as described in claim 1, characterized in that, The alkaline cleaning solution contains 10-30 g / L of sodium hydroxide, 3-8 g / L of corrosion inhibitor, and 5-15 g / L of complexing agent.

3. The method for processing the inner cavity of a 3D-printed liquid cooling plate as described in claim 1, characterized in that, The polishing additive includes at least one of an oxidant and a metal ion chelating agent.

4. The method for processing the inner cavity of a 3D-printed liquid-cooled plate as described in claim 3, characterized in that, The alkaline polishing solution contains 30-80 g / L of potassium hydroxide, 10-30 g / L of potassium carbonate, 5-15 g / L of oxidant, and 5-10 g / L of metal ion chelating agent.

5. The method for processing the inner cavity of a 3D-printed liquid-cooled plate as described in claim 1, characterized in that, The mixed acid solution comprises: 40% ~ 60% phosphoric acid; 10% ~ 20% sulfuric acid; 3% ~ 8% nitric acid; 0.5% ~ 2% surfactant; The remainder is deionized water.

6. The method for processing the inner cavity of a 3D-printed liquid cooling plate as described in claim 1, characterized in that, The film-forming additive includes at least one of fluorotitanic acid, sodium nitrate, organic film-forming aids, and pH adjusters.

7. The method for processing the inner cavity of a 3D-printed liquid cooling plate as described in claim 6, characterized in that, The film-forming solution contains 0.5 to 2.0 g / L of fluorozirconic acid, 0.1 to 0.5 g / L of fluorotitanic acid, 0.5 to 2.0 g / L of sodium nitrate, and 1.0 to 5.0 g / L of organic film-forming aids.

8. An internal cavity processing device, characterized in that, A method for processing the cavity of a 3D-printed liquid-cooled plate as described in any one of claims 1-7; The cavity processing device includes: Water bath, chemical tank, heating plate, circulating pump, water inlet, tee connector, waste liquid collection tank; The water bath is used to hold constant temperature water and workpieces; the chemical tank has multiple sub-tanks for holding different chemicals, and each sub-tank has an independent inlet and outlet control interface. The circulating pump is installed in the pipeline between the inlet ports of the chemical tank and the water bath; the inlet port of the water bath is also connected to the water inlet via a pipeline. The three-end interfaces of the tee connector are connected to the outlet interface of the water bath, the chemical tank and the waste liquid collection tank through corresponding pipes; The heating plate acts on the areas where the water bath and chemical tank are located.

9. The internal cavity processing device as described in claim 8, characterized in that, Both the water bath and the chemical tank are equipped with functional sensors, including at least one of temperature sensors, pressure sensors, and flow sensors. Among them, the temperature sensor is used in conjunction with the heating plate to control the solution temperature; Pressure sensors are used in conjunction with circulating pumps to control internal pressure; Flow sensors are used in conjunction with circulating pumps to control solution flow.

10. A method of using an internal cavity processing device, characterized in that, The cavity processing device is the cavity processing device as described in claim 8 or 9; The method of using the cavity treatment device includes: The 3D-printed liquid cooling plate is placed in a water bath, and the solutions in the water bath and chemical tank are heated to a preset temperature based on the heating plate; According to the processing flow of the 3D printed liquid cooling plate inner cavity treatment method, the inlet and outlet control interfaces of each chemical tank are opened in sequence, and the corresponding chemicals are introduced into the water bath tank through the circulation pump. The inner cavity of the 3D printed liquid cooling plate is subjected to alkaline activation, alkaline polishing, acid bright polishing, dust removal treatment and film protection treatment in sequence. In the alkaline activation, alkaline polishing, acidic bright polishing, dust removal, and film formation protection processes, a dynamic circulation injection method is used. The corresponding chemicals are pumped through the inner cavity channel and circulated to the corresponding tanks via a three-way connector. During the execution of each chemical treatment process, the direction of the three-way connector is from the water bath tank to the chemical tank. After each chemical treatment process is completed, room temperature clean water or deionized water is introduced through the inlet to clean the inner cavity before proceeding to the next process. During the inner cavity cleaning process, the direction of the T-connector is from the water bath to the waste liquid collection tank.

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