Repeated coloring method of anodized aluminum oxide material oxidation film
By using a carbon dioxide laser beam in the anodized aluminum oxide film to open the micropores and remove impurities, the problem of secondary coloring difficulties in the traditional anodized aluminum coloring process is solved, and the repeated coloring and color uniformity of the oxide film are achieved.
Patent Information
- Application Number
- CN202411636028.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-03-18
AI Technical Summary
In the traditional anodized aluminum coloring process, after the first coloring of the alumina film, the honeycomb holes are easily closed or there are air bubbles, which leads to difficulty in secondary coloring, even inability to proceed, and it is difficult to obtain a pure and uniform color.
After immersing the workpiece to be processed in the dye solution for initial coloration, the workpiece to be processed is irradiated with a laser beam generated based on carbon dioxide to focus on the workpiece to be processed to open the micropores in the oxide film and remove the dye solution or gas therein, ensuring that the dye can be adsorbed smoothly during secondary coloration.
Repeated coloring of the anodized aluminum oxide film is achieved, ensuring that the dyeing is mixed well and a more saturated and brighter color can be obtained.
Smart Images
Figure CN119640366A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of aluminum anodizing treatment process, and in particular to a method for repeated coloring of an anodized aluminum oxide film. Background Art
[0002] The anodized aluminum coloring process mainly includes two steps: anodizing and electrolytic coloring. First, the aluminum material is anodized in a specific electrolyte to form an aluminum oxide film. Subsequently, in an electrolyte containing a dye, the dye is adsorbed into the honeycomb pores of the aluminum oxide film by an electrolytic coloring method to achieve coloring. However, in the traditional anodized aluminum coloring process, after the anodized aluminum is colored for the first time, the honeycomb pores on the surface of the aluminum oxide film are easily closed or air bubbles exist, making secondary coloring difficult or even impossible. Even if secondary coloring is possible, pure and uniform color is often not obtained because the dye is difficult to fully penetrate into the closed honeycomb pores.
[0003] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention
[0004] The main purpose of the present application is to provide a method for repeated coloring of anodized aluminum oxide films, aiming to solve the technical problem of difficulty in secondary coloring in the traditional anodized aluminum coloring process.
[0005] To achieve the above purpose, the present application proposes a method for repeated coloring of an anodized aluminum oxide film, the method comprising: Immerse the workpiece to be processed in the dye solution for primary coloring; Using a laser beam generated based on carbon dioxide, focusing and irradiating the workpiece to be processed after the primary coloring, so as to open the micropores in the oxide film on the surface of the workpiece to be processed, and / or remove the dye solution or gas in the micropores; The workpiece to be processed is immersed in a dye solution for re-coloring.
[0006] In one embodiment, after the step of immersing the workpiece to be processed in a dye solution for re-coloring, the process further includes: If the coloring color does not reach the target color, repeating the steps of using the laser beam generated by carbon dioxide to focus and irradiate the workpiece to be processed after the initial coloring, and immersing the workpiece to be processed in a dye solution to perform coloring again; If the coloring color reaches the target color, the repeated coloring process ends.
[0007] In one embodiment, before the step of using a laser beam generated by carbon dioxide to focus and irradiate the workpiece to be processed after the initial coloring, the step further includes: Using running water to rinse the workpiece to be processed; The rinsed workpiece to be processed is fixed on a positioning fixture, and the positioning fixture and the workpiece to be processed are moved to a carbon dioxide laser workbench.
[0008] In one embodiment, the wavelength of the laser beam is 9.1-10.6 um, the laser emission frequency is 1-100 kHz or a continuous wave laser is used.
[0009] In one embodiment, the power of the carbon dioxide laser workbench is 5% to 35% of the maximum power.
[0010] In one embodiment, after the step of immersing the workpiece to be processed in a dye solution for primary coloring, the process further includes: Immersing the workpiece to be processed after the primary coloring in an alkaline or acidic degreasing agent to dissolve the oil stains on the surface of the workpiece to be processed; The workpiece to be processed is immersed in a neutralizer solution to neutralize the alkaline or acidic degreasing agent remaining on the surface of the workpiece to be processed.
[0011] In one embodiment, after the step of ending the repeated coloring process if the coloring color reaches the target color, the method further includes: After coloring, the workpiece to be processed is rinsed with running water; The rinsed workpiece to be processed is dried.
[0012] In one embodiment, before the step of drying the rinsed workpiece to be processed, the process further comprises: Immersing the workpiece to be processed in a sealing agent so that the dye solution is sealed in the micropores of the oxide film; The workpiece to be processed is rinsed with flowing water after the micropores are sealed.
[0013] In one embodiment, before the step of immersing the workpiece to be processed in the dye solution for primary coloring, the step further includes: Immersing the workpiece to be processed in an electrolyte; The workpiece to be processed is used as an anode and current is passed through it to obtain an oxide film containing the micropores.
[0014] In one embodiment, the thickness of the oxide film is in the range of 5-20 um.
[0015] The present application proposes a method for repeated coloring of an anodized aluminum oxide film. After the workpiece to be processed is immersed in a dye solution for initial coloring, a laser beam generated by carbon dioxide is used to focus and irradiate the workpiece to be processed after the initial coloring, so as to open the micropores in the oxide film on the surface of the workpiece to be processed, and / or remove the dye solution or gas in the micropores, so that when the workpiece to be processed is immersed in the dye solution for coloring again, the dye solution can be smoothly adsorbed into the micropores of the oxide film, thereby ensuring sufficient mixing of the dyeing. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0018] Figure 1 A schematic diagram of a process flow diagram provided for the first embodiment of the method for repeated coloring of anodized aluminum oxide film of the present application; Figure 2 A schematic diagram of a process flow diagram provided for the second embodiment of the method for repeated coloring of anodized aluminum oxide film of the present application; Figure 3 A schematic diagram of a process flow diagram provided for the third embodiment of the method for repeated coloring of anodized aluminum oxide film of the present application; Figure 4 A schematic flow chart of Example 6 of the repeated coloring method of anodized aluminum oxide film of the present application; Figure 5 A schematic flow chart of Embodiment 7 of the method for repeated coloring of anodized aluminum oxide film of the present application; Figure 6 A schematic diagram of a process flow diagram provided for Embodiment 8 of the method for repeated coloring of anodized aluminum oxide film of the present application; Figure 7 A schematic flow chart of Example 9 of the method for repeated coloring of anodized aluminum oxide film of the present application is provided.
[0019] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0020] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.
[0021] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.
[0022] The anodized aluminum coloring process mainly includes two steps: anodizing and electrolytic coloring. First, the aluminum material is anodized in a specific electrolyte to form an aluminum oxide film. Subsequently, in an electrolyte containing a dye, the dye is adsorbed into the honeycomb pores of the aluminum oxide film by an electrolytic coloring method to achieve coloring. However, in the traditional anodized aluminum coloring process, after the anodized aluminum is colored for the first time, the honeycomb pores on the surface of the aluminum oxide film are easily closed or air bubbles exist, making secondary coloring difficult or even impossible. Even if secondary coloring is possible, pure and uniform color is often not obtained because the dye is difficult to fully penetrate into the closed honeycomb pores.
[0023] In view of the above problems, the present application proposes a method for repeated coloring of anodized aluminum oxide film. After the workpiece to be processed is immersed in a dye solution for the first coloring, a laser beam generated by carbon dioxide is focused and irradiated on the micropores in the oxide film on the surface of the workpiece to be processed to open the closed micropores and remove the dye solution or gas in the micropores. When the workpiece to be processed is immersed in the dye solution for the second coloring, the dye solution can be smoothly adsorbed into the micropores of the oxide film to ensure sufficient mixing of the dyeing.
[0024] Based on this, the first embodiment proposed in this application provides a method for repeatedly coloring an anodized aluminum oxide film, referring to Figure 1 In this embodiment, the repeated coloring method of the anodized aluminum oxide film includes steps S10 to S30: Step S10, immersing the workpiece to be processed in a dye solution for primary coloring.
[0025] It should be noted that the dye solution is an aqueous solution containing a dye or other chemical substances such as a dye accelerator or a color fixing agent.
[0026] Prepare the appropriate dye solution according to the desired color. For example, if you want to dye the aluminum workpiece black, you can use Acid Black 1 (CI28425) as the dye; sulfuric acid as the acidifier, copper sulfate as the mordant to help the dye adsorb on the surface of the aluminum workpiece; then add distilled water for the dye and other chemical components to form a dye solution. After that, use a conveyor belt or a robotic arm to deliver the aluminum workpiece into the dye solution.
[0027] Optionally, a dyeing tank may be provided, which is filled with a dye solution, and the aluminum part to be processed is dipped into the dyeing tank through a machine-controlled fixture or basket to achieve coloring.
[0028] Step S20, using a laser beam generated based on carbon dioxide to focus and irradiate the workpiece to be processed after the initial coloring, so as to open the micropores in the oxide film on the surface of the workpiece to be processed and / or remove the dye solution or gas in the micropores.
[0029] It should be noted that the laser beam generated based on carbon dioxide can be emitted by a carbon dioxide laser. When the carbon dioxide laser is working, a gas mixture containing carbon dioxide is placed in the discharge tube of the carbon dioxide laser. When the current passes through the discharge tube, the molecules in the gas are excited, causing the electrons to jump from a low energy level to a high energy level. Subsequently, when these electrons return to a low energy level, photons are released, which are reflected back and forth by the reflectors at both ends of the discharge tube to form a laser. The gas mixture may also include helium and nitrogen.
[0030] After the CO2 laser generates a laser beam, it can be focused through a lens system. The focused laser beam is aimed at the micropores in the oxide film on the surface of the aluminum workpiece to be processed. The high energy of the laser beam causes the closed film above the micropores to evaporate or decompose, and the laser beam continues to irradiate until the micropores are opened. The high temperature of the laser beam can evaporate the dye solution in the micropores and generate heat to squeeze out the gas in the micropores.
[0031] It should also be noted that there is usually a naturally formed aluminum oxide film on the surface of aluminum workpieces. This film has a low absorption rate for visible light and near-infrared light, so the absorption rate of aluminum workpieces in these wavelength ranges is also low. As the wavelength increases, the energy of the photon decreases, which allows the photon to penetrate the oxide layer on the surface of the aluminum workpiece and interact with the aluminum workpiece body. In the far-infrared region, especially when the wavelength is close to or exceeds 10um, the absorption rate of aluminum workpieces increases significantly. Conventional other lasers such as fiber lasers have a shorter wavelength (about 1.06um), so the reflectivity of aluminum workpieces is higher and the absorption rate is lower, resulting in reduced fiber laser processing efficiency and increased aluminum workpiece loss. In contrast, the laser wavelength emitted by the carbon dioxide laser (about 10.6um) is closer to the wavelength of the absorption peak of the aluminum workpiece, so the absorption rate of the aluminum workpiece to the carbon dioxide laser is higher, which makes it easier to open the sealing of the oxide film on the surface of the aluminum workpiece.
[0032] In addition, due to the low absorption rate of other types of lasers, the laser energy needs to penetrate the surface of the material and penetrate deep into the material before it can be absorbed. This will lead to a wider distribution of heat, resulting in more serious thermal damage, such as oxidation and deformation of the material surface. However, the heat affected zone generated by carbon dioxide laser processing of aluminum workpieces is smaller, which can reduce the thermal damage of aluminum workpieces and reduce the loss of oxide film on the surface of aluminum workpieces.
[0033] Step S30, immersing the workpiece to be processed in a dye solution for re-coloring.
[0034] After the aluminum workpiece is initially colored and laser treated, it is immersed in the dye solution again using automated equipment such as a robotic arm or a conveyor belt. In the dye solution, the dye molecules enter the oxide film on the surface of the aluminum workpiece through the opened micropores, achieving secondary coloring.
[0035] It should be noted that, since the impurities and oxide layer in the micropores are removed by the laser beam in the previous laser treatment step, the micropores can absorb the dye more effectively, so the secondary coloring can produce more saturated and brighter colors.
[0036] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can refer to the above introduction, and will not be repeated later. Figure 2 After step S30, the method for repeated coloring of anodized aluminum oxide film further includes steps S40 to S50: Step S40, if the coloring color does not reach the target color, repeat the steps of using the laser beam generated by carbon dioxide to focus and irradiate the workpiece to be processed after the initial coloring, and immersing the workpiece to be processed in a dye solution for re-coloring.
[0037] Step S50: if the colored color reaches the target color, the repeated coloring process ends.
[0038] Optionally, after the aluminum material to be processed is recolored, the coloring effect of the aluminum material is checked to determine whether further coloring is required. If it is decided to color it again, the surface of the workpiece is treated again using a carbon dioxide laser beam to open the micropores and remove the dye solution or gas therein.
[0039] For example, the aluminum material to be processed after secondary coloring is placed on the workbench of the carbon dioxide laser and fixed to ensure that the aluminum workpiece does not move or deform during the cleaning process. Turn on the carbon dioxide laser, and the laser emits a high-energy laser beam. The laser beam irradiates the oxide film on the surface of the aluminum workpiece through the light guide system, causing the film closed at the top of the oxide film micropores to expand, vaporize or reach the ignition point instantly due to heat. While laser irradiation, a protective gas such as nitrogen can be introduced as needed to prevent the surface of the aluminum workpiece from being oxidized or producing other chemical reactions.
[0040] Among them, the main function of the light guide system is to transmit the laser beam emitted by the carbon dioxide laser to the surface of the workpiece, ensuring that the laser can accurately irradiate the area that needs to be cleaned to avoid damage to other areas. Optionally, the laser is transmitted using the total reflection principle of the optical fiber. After the laser beam enters the optical fiber, due to the total reflection principle of the optical fiber, the laser is reflected multiple times inside the optical fiber, with a long transmission distance and good directionality. The laser irradiation direction can be flexibly adjusted, and the laser beam is finally transmitted to the surface of the aluminum workpiece. Optionally, a reflector can also be used to reflect the laser to change the laser irradiation direction.
[0041] For example, install the CO2 laser on a stable platform to ensure that it does not shake during operation, place the workpiece to be processed in the processing area of the CO2 laser, and adjust the position and angle of the workpiece to be processed so that the laser beam can irradiate the workpiece surface vertically. Use the scale or focal length indicator provided by the CO2 laser to preliminarily adjust the focal length. For example, rotate the lens or focal length adjustment hand wheel until the focal point diameter reaches the minimum value or meets the processing requirements. By accurately adjusting the focal length, it can be ensured that the laser beam can be accurately focused on the micropores of the oxide film on the surface of the workpiece to be processed, reduce thermal damage and deformation of other parts of the surface of the workpiece to be processed, and effectively remove the dye solution or gas in the micropores.
[0042] Optionally, partial areas of the oxide film on the surface of the aluminum workpiece may be selectively laser treated, and dyes of other colors may be immersed in the micropores opened after the laser treatment to achieve a more complex dyeing effect.
[0043] By repeating laser treatment and dyeing, the depth and uniformity of color can be gradually improved, and the number of dyeing can be adjusted as needed to achieve a specific color effect.
[0044] Based on the above embodiments of the present application, in the third embodiment of the present application, the same or similar contents as those in the above embodiments can be referred to the above introduction, and will not be described in detail later. Figure 3 Before step S20, the method for repeatedly coloring the anodized aluminum oxide film further includes steps S60 to S70: Step S60: flushing the workpiece to be processed with running water.
[0045] It should be noted that the rinsing step is used to remove excess dye, floating color and impurities on the surface of the aluminum workpiece to ensure dyeing uniformity and cleanliness.
[0046] For example, a flowing water system is set up, and appropriate water pressure, flow rate and water temperature are adjusted. The aluminum workpiece to be processed after the first coloring is placed under flowing water, and the water is allowed to evenly wash the surface of the aluminum workpiece, remove the dye and impurities on the surface, and provide a clean surface for subsequent process steps.
[0047] Step S70, fixing the rinsed workpiece to be processed on a positioning fixture, and moving the positioning fixture and the workpiece to be processed to a carbon dioxide laser workbench.
[0048] It should be noted that the positioning fixture is used to fix, position and support the workpiece to be processed during the processing, to ensure the accurate position of the workpiece to be processed during processing, to reduce processing errors, and to improve production efficiency and product quality. Among them, the workpiece to be processed can be fixed on the fixture using the mechanical arm or clamp of the fixture, or a pressure plate can be used to cover the workpiece to be processed, and the workpiece to be processed can be fixed by applying pressure through bolts or fixtures. In addition, there are other methods such as adhesive fixation and positioning pin fixation, which are not limited in detail in this application.
[0049] For example, first make sure the CO2 laser is in good working condition, check whether the power supply, connecting wires, etc. are intact, and avoid malfunctions during the cleaning process. Then select or design a suitable positioning fixture to ensure the stability of the aluminum workpiece to be processed during the laser processing. Place the rinsed and dried aluminum workpiece to be processed on the positioning fixture and secure it firmly with a clamp or other fixing device. Move the positioning fixture with the aluminum workpiece to be processed to the correct position of the CO2 laser workbench to prevent accidental movement during the laser processing process and improve operational safety.
[0050] Based on the above embodiments of the present application, in the fourth embodiment of the present application, the same or similar contents as those in the above embodiments can be referred to the above description, and no further description will be given later. On this basis, the wavelength of the laser beam is 9.1-10.6 um, the laser emission frequency is 1-100 kHz or a continuous wave laser is used.
[0051] It should be noted that aluminum workpieces have a good absorption rate for CO2 lasers with a wavelength of about 9.1~10.6um, which helps the laser energy to be absorbed by the material more effectively and enhances the efficiency of laser processing. When the laser emission frequency is too low, it is easy to form laser textures on the oxide film on the surface of the aluminum workpiece. When the laser emission frequency is too high, the overlap rate of the laser increases, the heat increases, and the risk of thermal deformation of the aluminum workpiece increases when laser processing is performed on a large area of aluminum workpieces. The laser texture generated will also increase, affecting the dyeing effect.
[0052] Optionally, adjusting the laser emission speed according to actual conditions, for example, setting the laser emission speed to be greater than or equal to 100 mm / s can reduce the heating time of the aluminum workpiece during processing, thereby reducing the range of the heat-affected zone and reducing the possibility of material deformation and thermal damage.
[0053] Optionally, a CW (Continuous Wave) laser is used to provide uninterrupted laser output. The energy distribution of a continuous wave laser is in a Gaussian mode, that is, the energy distribution of the laser beam cross section is in a Gaussian (normal distribution) form with the highest energy in the center and gradually decreasing outward. This distribution characteristic enables the CW laser to achieve extremely high focusing accuracy and processing effect during precision machining, so as to more accurately remove the pigment in the micropores of the oxide film on the surface of the aluminum workpiece to be processed, and reduce deformation and thermal damage of the material.
[0054] For example, according to the thickness and size of the aluminum workpiece to be processed and the area to be irradiated, the output power, laser emission speed, laser emission frequency and other parameters of the carbon dioxide laser are adjusted. At the same time, the energy output of the laser beam is monitored in real time and adjusted as needed.
[0055] Specifically, according to the thickness of the aluminum workpiece and the thickness of the oxide film, select appropriate output power laser emission speed, laser emission frequency and other parameters. For example, a thicker aluminum workpiece oxide film requires a higher output power to improve the penetration of the laser beam so that it can penetrate a thicker oxide film seal to achieve a cleaning or processing effect. Among them, the output power can be accurately adjusted through the control panel of the carbon dioxide laser or an external control system. The control panel of the carbon dioxide laser may include components such as a display, a keyboard, a knob, and a button. The display is used to display the operating status, parameter settings and other information of the carbon dioxide laser; the keyboard and the knob are used to input and adjust parameters such as output power, laser emission speed, etc.; the button is used to start, stop the carbon dioxide laser or switch the working mode. The operator can accurately adjust the output power by rotating the knob or entering a numerical value. An independent computer or a dedicated controller can also be used to remotely monitor and control the operation of the carbon dioxide laser. The independent computer or dedicated controller is connected to the carbon dioxide laser via a data cable or wirelessly, and the operating status and parameter information of the carbon dioxide laser can be obtained in real time. The operator can input or select the required output power value and other parameter data through the software interface of the computer or dedicated controller.
[0056] Optionally, during the laser irradiation process, the irradiation effect of the laser beam and the changes on the workpiece surface are continuously monitored. A high-definition camera or other monitoring equipment can be set on the carbon dioxide laser transmitter to capture the irradiation of the laser beam and the changes on the workpiece surface in real time. During the laser irradiation process, the operator needs to pay close attention to the monitoring screen, observe the irradiation effect of the laser beam and the changes on the workpiece surface, pay attention to whether the focus of the laser beam is stable, whether the spot size is uniform, whether the shape is regular, and whether there are abnormal conditions such as thermal damage, cracks or residues on the workpiece surface. According to the observed abnormal conditions, analyze the causes and adjust the processing parameters, such as output power, emission speed, etc., re-perform laser irradiation, and continue to monitor the irradiation effect of the laser beam and the changes on the workpiece surface until the ideal processing effect is achieved.
[0057] It should be noted that the above-mentioned laser emission frequency and laser emission speed can be adjusted according to the specific thickness and shape of the aluminum workpiece.
[0058] In this embodiment, the use of a longer wavelength and an appropriate emission frequency combined with high-speed scanning helps to reduce the heat-affected zone of the aluminum workpiece during laser processing, thereby reducing the risk of deformation and thermal damage to the aluminum workpiece.
[0059] Based on the above embodiments of the present application, in the fifth embodiment of the present application, the same or similar contents as those in the above embodiments can be referred to the above introduction, and no further description will be given later. On this basis, the power of the carbon dioxide laser workbench is 5% to 35% of the maximum power.
[0060] It should be noted that too high CO2 laser working power will lead to an increase in the heat-affected zone of the material, which can easily lead to overheating of the material, ablation and melting, causing large thermal deformation and stress, and affecting processing accuracy. Too low CO2 laser working power will slow down the processing speed, and for some dyes that adhere strongly after one coloring and require higher energy to remove, low power may not be enough to achieve effective removal, resulting in incomplete processing.
[0061] Using 5% to 35% of the maximum power as the working power during laser processing can reduce the heat-affected zone of the material, reduce the ablation and melting of the material surface, and avoid excessive thermal damage. At the same time, it ensures that the evaporation and removal of dyes or gases in the micropores of the aluminum oxide film are more uniform.
[0062] Based on the above embodiments of the present application, in the sixth embodiment of the present application, the same or similar contents as those in the above embodiments can be referred to the above introduction, and will not be described in detail later. Figure 4 After step S10, the method for repeated coloring of anodized aluminum oxide film further includes steps S80 to S90: Step S80, immersing the workpiece to be processed after the initial coloring into an alkaline or acidic degreasing agent to dissolve the oil stains on the surface of the workpiece to be processed.
[0063] It should be noted that the purpose of degreasing is to remove oil, lubricants or other organic substances from the surface of the workpiece to be processed, because these substances may hinder subsequent processing steps, such as coloring, coating application, etc.
[0064] Exemplarily, the aluminum workpiece to be processed is immersed in an alkaline or acidic degreaser. For example, a sodium hydroxide (NaOH) solution can be used as an alkaline degreaser, or phosphoric acid (H3PO4) can be used as an acidic degreaser. Depending on the concentration of the degreaser and the severity of the oil stains on the workpiece, the immersion time can range from a few minutes to tens of minutes. During the immersion process, the degreaser will chemically react with the oil stains on the surface of the workpiece, dissolving them and removing them from the surface of the workpiece.
[0065] Step S90, immersing the workpiece to be processed in a neutralizer solution to neutralize the alkaline or acidic degreasing agent remaining on the surface of the workpiece to be processed.
[0066] It should be noted that the purpose of the neutralization treatment is to balance the pH value of the workpiece surface and ensure that there is no excess acidic or alkaline substances on the workpiece surface, thereby preventing the residual acidic or alkaline substances from reacting with the fuel solution and affecting the subsequent coloring effect.
[0067] For example, the degreased aluminum workpiece is immersed in a neutralizer solution. If an alkaline degreaser was used before, an acidic neutralizer such as acetic acid (CH3COOH) solution can be used; if an acidic degreaser was used, an alkaline neutralizer such as sodium carbonate (Na2CO3) solution can be used. Soak for a period of time to ensure that the neutralizer is fully effective and balances the pH value of the aluminum workpiece surface. The neutralizer reacts with the degreaser remaining on the surface of the aluminum workpiece to generate water and salt, thereby neutralizing the excess acid and alkaline substances.
[0068] In this embodiment, the degreasing step can effectively remove the oil stains on the surface of the workpiece, providing a clean surface for the subsequent processing steps, thereby improving the adhesion between the colorant or coating and the workpiece surface. The neutralization step can prevent the workpiece to be processed from being corroded by residual acidic and alkaline substances, and by ensuring the chemical balance of the surface of the workpiece to be processed, it can avoid adverse reactions in the subsequent coloring process, thereby improving the overall processing quality.
[0069] Based on the above embodiments of the present application, in the seventh embodiment of the present application, the same or similar contents as those in the above embodiments can be referred to the above introduction, and will not be described in detail later. Figure 5 After step S50, the method for repeated coloring of anodized aluminum oxide film further includes steps S100 to S110: Step S100, using running water to rinse the workpiece to be processed after coloring is completed.
[0070] Step S110, drying the rinsed workpiece.
[0071] After the coloring of the workpiece to be processed is completed, the workpiece to be processed is rinsed with clean running water to remove excess dye and other impurities attached to the surface, and the rinsed workpiece to be processed is dried to remove moisture from the surface of the workpiece to be processed. For example, the workpiece to be processed is placed in a hot air dryer, and an appropriate temperature and time are set, and hot air is blown on the surface of the workpiece to be processed to quickly evaporate moisture.
[0072] Based on the above embodiments of the present application, in the eighth embodiment of the present application, the same or similar contents as those in the above embodiments can be referred to the above introduction, and will not be described in detail later. Figure 6 Before step S110, the method for repeatedly coloring anodized aluminum oxide film further includes steps S120 to S130: Step S120, immersing the workpiece to be processed in a sealing agent so that the dye solution is sealed in the micropores of the oxide film.
[0073] It should be noted that the sealer is used to seal the micropores on the surface of the workpiece to protect the internal dye from oxidation, protect the color and gloss of the workpiece, and make its appearance more durable.
[0074] For example, a suitable sealer is selected, such as resin, wax or special chemicals, and the workpiece is completely immersed in the sealer to ensure that the sealer contacts all microporous surfaces for a certain time so that the sealer can fully act and cure.
[0075] Step S130, using running water to rinse the workpiece to be processed after the micropores are sealed.
[0076] Exemplarily, the sealed workpiece is placed under running water, which may be tap water, deionized water or purified water, to remove the sealing agent and other possible contaminants remaining on the surface to ensure that the workpiece is clean.
[0077] Based on the above embodiments of the present application, in the ninth embodiment of the present application, the same or similar contents as those in the above embodiments can be referred to the above introduction, and will not be described in detail later. Figure 7 Before step S10, the method for repeated coloring of anodized aluminum oxide film further includes steps S140 to S150: Step S140, immersing the workpiece to be processed in an electrolyte.
[0078] Step S150, using the workpiece to be processed as an anode and passing an electric current to obtain an oxide film containing the micropores.
[0079] Select a suitable electrolyte, such as a solution containing sulfuric acid, oxalic acid or other chemical substances suitable for metal oxidation. Immerse the cleaned workpiece completely in the electrolyte and connect the workpiece to the positive pole of the power supply. The negative pole of the power supply can be a conductive metal plate or mesh. After power is turned on, the current passes through the workpiece to be processed, triggering the anodic oxidation reaction.
[0080] For example, taking an aluminum workpiece as an example, it is immersed in an electrolyte containing sulfuric acid and then anodized by direct current to form an aluminum oxide film with a microporous structure.
[0081] Specifically, first, preheat the electrolyte to a suitable temperature, slowly immerse the aluminum workpiece into the electrolyte, and ensure that no bubbles are attached to the surface of the aluminum workpiece. Then start the power supply, gradually increase the current to a predetermined value, keep it constant or adjust it according to the process requirements, and maintain the current for a period of time, usually tens of minutes, depending on the thickness and hardness of the required oxide film. During the electrolysis process, monitor the temperature and voltage of the electrolyte to ensure the stability of the oxidation process. After the electrolysis is completed, gradually reduce the current until the power is turned off, and then take out the aluminum workpiece.
[0082] In a feasible implementation, the thickness of the oxide film can be controlled within the range of 5 to 20 um. Because if the oxide film is too thin, the porosity of the oxide film surface is insufficient, which will lead to insufficient dye adsorption, uneven dyeing effect, and the color may be light. An oxide film that is too thick may become brittle and easily break during processing or use, and an oxide film that is too thick requires longer processing time and higher energy consumption, thereby increasing production costs. The thickness of the oxide film can be controlled within the range of 5 to 20 um. The oxide film has sufficient porosity and can effectively adsorb dye molecules, thereby achieving a uniform and lasting dyeing effect. It can also provide a sufficient protective layer to prevent the aluminum workpiece from being further corroded, so that the aluminum workpiece presents a good color and texture, and improves the appearance quality of the product.
[0083] It should be noted that the above description is only a partial embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural transformations made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.
Claims
1. A method for repeated coloring of anodized aluminum oxide film, characterized in that: The method comprises: Immerse the workpiece to be processed in the dye solution for primary coloring; Using a laser beam generated based on carbon dioxide, focusing and irradiating the workpiece to be processed after the primary coloring, so as to open the micropores in the oxide film on the surface of the workpiece to be processed, and / or remove the dye solution or gas in the micropores; The workpiece to be processed is immersed in a dye solution for re-coloring.
2. The method for repeated coloring of anodized aluminum oxide film according to claim 1, characterized in that: After the step of immersing the workpiece to be processed in a dye solution for re-coloring, the process further includes: If the coloring color does not reach the target color, repeating the steps of using the laser beam generated by carbon dioxide to focus and irradiate the workpiece to be processed after the initial coloring, and immersing the workpiece to be processed in a dye solution to perform coloring again; If the coloring color reaches the target color, the repeated coloring process ends.
3. The method for repeated coloring of anodized aluminum oxide film according to any one of claims 1 to 2, characterized in that: Before the step of using a laser beam generated by carbon dioxide to focus and irradiate the workpiece to be processed after the initial coloring, the process further includes: Using running water to rinse the workpiece to be processed; The rinsed workpiece to be processed is fixed on a positioning fixture, and the positioning fixture and the workpiece to be processed are moved to a carbon dioxide laser workbench.
4. The method for repeated coloring of anodized aluminum oxide film according to claim 1, characterized in that: The wavelength of the laser beam is 9.1-10.6 um, and the laser emission frequency is 1-100 kHz or a continuous wave laser is used.
5. The method for repeated coloring of anodized aluminum oxide film according to claim 1, characterized in that: The power of the carbon dioxide laser workbench is 5% to 35% of the maximum power.
6. The method for repeated coloring of anodized aluminum oxide film according to claim 1, characterized in that: After the step of immersing the workpiece to be processed in the dye solution for primary coloring, the method further comprises: Immersing the workpiece to be processed after the primary coloring in an alkaline or acidic degreasing agent to dissolve the oil stains on the surface of the workpiece to be processed; The workpiece to be processed is immersed in a neutralizer solution to neutralize the alkaline or acidic degreasing agent remaining on the surface of the workpiece to be processed.
7. The method for repeated coloring of anodized aluminum oxide film according to claim 2, characterized in that: After the step of ending the repeated coloring process if the coloring color reaches the target color, the method further includes: After coloring, the workpiece to be processed is rinsed with running water; The rinsed workpiece to be processed is dried.
8. The method for repeated coloring of anodized aluminum oxide film according to claim 7, characterized in that: Before the step of drying the rinsed workpiece to be processed, the process further comprises: Immersing the workpiece to be processed in a sealing agent so that the dye solution is sealed in the micropores of the oxide film; The workpiece to be processed is rinsed with flowing water after the micropores are sealed.
9. The method for repeated coloring of anodized aluminum oxide film according to claim 1, characterized in that: Before the step of immersing the workpiece to be processed in the dye solution for primary coloring, the method further comprises: Immersing the workpiece to be processed in an electrolyte; The workpiece to be processed is used as an anode and current is passed through it to obtain an oxide film containing the micropores.
10. The method for repeated coloring of anodized aluminum oxide film according to claim 9, characterized in that: The thickness of the oxide film is in the range of 5 to 20 um.