How to remove aluminum extrusion lines

Abstract

A method for removing aluminum extrusion marks comprises the following steps: providing an aluminum extrusion workpiece having aluminum extrusion marks on its surface; performing an alkaline etching treatment on the aluminum extrusion workpiece; performing a black film stripping treatment on the aluminum extrusion workpiece after the alkaline etching treatment; polishing the aluminum extrusion workpiece after the black film stripping treatment; cleaning the polished aluminum extrusion workpiece; and sandblasting the cleaned aluminum extrusion workpiece. The method for removing aluminum extrusion marks provided in this application sequentially removes the aluminum extrusion marks on the surface of the aluminum extrusion workpiece through alkaline etching, black film stripping, polishing, cleaning, and sandblasting. The removal method is simple and low-cost.

Description

Technical Field

[0001] The present application relates to the field of surface treatment, and in particular to a method for removing aluminum extrusion lines. Background Art

[0002] Aluminum extrusions are prone to producing wavy lines on their surfaces, especially on irregularly shaped aluminum alloy products. The presence of wavy lines can reduce product precision, lower product quality, affect post-processing (such as dyeing), and affect product aesthetics. Summary of the Invention

[0003] In view of this, it is necessary to provide an effective method for removing aluminum extrusion to solve the above problems.

[0004] A method for removing aluminum extrusion lines comprises the following steps:

[0005] Providing an aluminum extrusion workpiece, wherein the surface of the aluminum extrusion workpiece has aluminum extrusion patterns;

[0006] alkaline etching the aluminum extruded workpiece;

[0007] Stripping the aluminum extruded workpiece after the alkaline etching treatment;

[0008] Polishing the aluminum extruded workpiece after the black film stripping treatment;

[0009] Cleaning and polishing of aluminum extrusions; and

[0010] Aluminum extrusion parts after sandblasting and cleaning.

[0011] Furthermore, the alkaline etching treatment step includes:

[0012] The aluminum extruded workpiece is placed in an alkaline etching solution containing sodium hydroxide for alkaline etching treatment; wherein the concentration of the sodium hydroxide is 50g / L-70g / L.

[0013] Furthermore, the temperature of the alkaline etching treatment of the aluminum extruded workpiece in the alkaline etching solution is 57° C.-63° C., and the time of the alkaline etching treatment is 4.5 min-5.5 min.

[0014] Furthermore, the step of stripping the black film of the aluminum extruded workpiece after the alkaline etching treatment includes:

[0015] The aluminum extrusion workpiece is placed in a bath containing nitric acid to perform black film stripping treatment; wherein the mass fraction of the nitric acid is 5%-10%.

[0016] Furthermore, the aluminum extruded workpiece is polished using a grinding sheet, and the grinding sheet includes at least one of sandpaper, sponge sand, a thousand-thread wheel and a nylon sheet.

[0017] Furthermore, during the polishing process, the pressure applied to the aluminum extruded workpiece is 2.0N-3.5N.

[0018] Furthermore, the cleaning process includes a degreasing process and a pickling process.

[0019] Furthermore, the degreasing treatment is to use an alkaline washing solution to clean the aluminum extruded workpiece, and the alkaline washing solution contains an alkali; the pickling treatment is to use an acid washing solution to clean the aluminum extruded workpiece, and the acid washing solution contains an acid.

[0020] Furthermore, spray treatment is performed after the degreasing treatment and the pickling treatment, and the pH of the water used in the spray treatment is 4-8.

[0021] Furthermore, the surface of the aluminum extruded workpiece includes a flat surface and a special-shaped surface; for the flat surface, the gas pressure during processing is 2.0 kgf / cm 2 -2.2kgf / cm 2 For the profiled surface, the pressure during processing is 2.7kgf / cm 2 -2.9kgf / cm 2 .

[0022] The method for removing aluminum extrusion provided in the present application gradually removes the aluminum extrusion marks on the surface of an aluminum extruded workpiece through alkaline etching, black film stripping, polishing, cleaning and sandblasting. The removal method is simple and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flow chart of a method for removing aluminum extrusion lines according to an embodiment of the present application.

[0024] Figure 2 This is a schematic structural diagram of an aluminum extrusion workpiece provided in one embodiment of the present application.

[0025] Figure 3 A schematic structural diagram of a thread-pulling wheel according to an embodiment of the present application.

[0026] Figure 4 for Figure 3 The schematic diagram of the structure of the blade unit on each blade of the mill wheel is shown.

[0027] Figure 5 For cleaning Figure 2 Schematic diagram of the connecting surface of the flat surface and the curved surface of the aluminum extruded workpiece shown.

[0028] Figure 6 For cleaning Figure 2 Schematic diagram of the curved surface of the aluminum extrusion workpiece shown.

[0029] Description of main component symbols

[0030] Aluminum extrusion parts 100

[0031] Plane 11

[0032] Surface 12

[0033] Connection surface 13

[0034] Thousand Silk Wheel 20

[0035] Blade 21

[0036] Blade unit 22

[0037] Routes L1, L2, L3

[0038] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0039] In order to be able to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth in order to fully understand the present application. The embodiments described are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes all and any combinations of one or more of the relevant listed items.

[0041] In the various embodiments of the present application, for ease of description and not limitation, the term "connection" used in the patent specification and claims of the present application is not limited to physical or mechanical connections, whether direct or indirect. "Up," "down," "above," "below," "left," "right," etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0042] See also Figure 1 The present invention provides a method for removing aluminum extrusion lines, comprising the following steps:

[0043] Step S1: providing an aluminum extrusion workpiece 100 , wherein the surface of the aluminum extrusion workpiece 100 has aluminum extrusion patterns.

[0044] The aluminum extruded workpiece 100 is formed by passing a high-temperature softened aluminum ingot through an aluminum extrusion die under strong extrusion in an aluminum extruder to form an aluminum profile product having a desired shape. During the extrusion process, the aluminum ingot forms the aluminum extrusion pattern, particularly the aluminum extruded workpiece 100 having a special-shaped surface.

[0045] The raw material of the aluminum extruded workpiece 100 is aluminum or an aluminum alloy, including but not limited to one of aluminum alloy series 5, aluminum alloy series 6, and aluminum alloy series 7. The main elements of aluminum alloy series 5 include aluminum and magnesium, the main elements of aluminum alloy series 6 include aluminum, magnesium, and silicon, and the main elements of aluminum alloy series 7 include aluminum, magnesium, zinc, and copper.

[0046] Step S2: alkaline etching treatment is performed on the aluminum extruded workpiece 100 .

[0047] The aluminum extruded workpiece 100 is placed in an alkaline etching solution containing sodium hydroxide (NaOH) for alkaline etching treatment. The alkaline etching treatment can also remove oil stains on the surface of the aluminum extruded workpiece 100; further, the alkaline etching treatment can also remove some aluminum extrusion lines on the surface of the aluminum extruded workpiece 100, such as aluminum extrusion lines with a depth of 0.01mm-0.05mm.

[0048] The concentration of NaOH in the alkaline etching solution is 50 g / L-70 g / L, and the alkaline etching solution can be prepared from a NaOH solution with a mass fraction of 40%-50%. If the concentration of NaOH is too low, the oil stains on the surface of the aluminum extruded workpiece 100 cannot be effectively removed, and some of the oil stains remain on the surface of the aluminum extruded workpiece 100, affecting the subsequent treatment effect. If the concentration of NaOH is too high, it is difficult to control the speed of the alkaline etching treatment, and the aluminum extruded workpiece 100 is prone to unintended reaction with NaOH, resulting in excessive corrosion of the surface of the aluminum extruded workpiece 100.

[0049] The alkaline etching treatment time of the aluminum extruded workpiece 100 in the alkaline etching solution is 4.5 minutes to 5.5 minutes. If the alkaline etching treatment time is too short, the oil stains on the surface of the aluminum extruded workpiece 100 cannot be effectively removed, and some oil stains remain on the surface of the aluminum extruded workpiece 100, affecting the subsequent treatment effect; if the alkaline etching treatment time is too long, the aluminum extruded workpiece 100 is likely to react unexpectedly with NaOH, resulting in excessive corrosion of the surface of the aluminum extruded workpiece 100.

[0050] The alkaline etching temperature of the aluminum extruded workpiece 100 in the alkaline etching solution is 57° C. to 63° C. If the alkaline etching temperature is too low, the alkaline etching speed is too slow, and the oil stains on the surface of the aluminum extruded workpiece 100 cannot be effectively removed; if the alkaline etching temperature is too high, it is difficult to control the alkaline etching speed.

[0051] In a specific embodiment, a NaOH solution with a mass fraction of 45% is prepared into an alkaline etching solution with a concentration of 60 g / L, and the aluminum extruded workpiece 100 is placed in the alkaline etching solution at a temperature of 60° C. for treatment for 5 minutes.

[0052] During the alkaline etching process, the aluminum in the aluminum extruded workpiece 100 reacts with NaOH to produce Al 3+ Dissolved in the alkaline etching solution. Further, during the treatment process, the Al 3+ The concentration in the alkaline etching solution is less than or equal to 35g / L. 3+ If the concentration in the alkaline etching solution is greater than 35 g / L, the effect of the alkaline etching treatment will be reduced.

[0053] After the alkaline etching treatment, the aluminum extruded workpiece 100 is washed with water to remove the alkaline etching liquid remaining on the surface of the aluminum extruded workpiece 100 to prevent the residual alkaline etching liquid from reacting with the aluminum extruded workpiece 100 and damaging the surface of the aluminum extruded workpiece 100.

[0054] Step S3: stripping the black film of the aluminum extruded workpiece 100.

[0055] The aluminum extruded workpiece 100 after alkaline etching is placed in a bath containing nitric acid (HNO3) for black film stripping treatment to remove the oxide film on the surface of the aluminum extruded workpiece 100, such as magnesium oxide, silicon dioxide, etc., to improve the surface smoothness of the aluminum extruded workpiece 100. It also helps to improve the conductivity of the aluminum extruded workpiece 100, which is convenient for subsequent treatment (such as anodizing).

[0056] Furthermore, the bath liquid also includes a stain remover and a dust remover, which removes oil, dust, etc. on the surface of the aluminum extruded workpiece 100 to ensure the smoothness of the surface of the aluminum extruded workpiece 100.

[0057] The bath solution includes HNO3 at a volume concentration of 1.4g / mL to 2.1g / mL and a stain remover at a volume concentration of 0.66g / mL to 1.32g / mL. The nitric acid in the bath solution is prepared from a 68% nitric acid stock solution, and the stain remover is prepared from a 90% by mass stain remover stock solution.

[0058] The aluminum extruded workpiece 100 is placed in the bath for treatment at room temperature for 50s-70s.

[0059] After the black film stripping process, the aluminum extruded workpiece 100 is washed with water to remove the bath liquid remaining on the surface of the aluminum extruded workpiece 100 and prevent the residual bath liquid from reacting with the aluminum extruded workpiece 100 .

[0060] Step S4: polishing the aluminum extruded workpiece 100 .

[0061] See also Figure 2 In this embodiment, the surface of the aluminum extruded workpiece 100 includes a flat surface 11, a curved surface 12, and a connecting surface 13 between the flat and curved surfaces. Different polishing methods can be used for different surfaces to further remove aluminum extrusion lines. The processing steps are flexible and can be processed according to the different shapes of the aluminum extruded workpiece 100. It should be understood that the shape of the aluminum extruded workpiece 100 described in this embodiment is only an example and is not intended to be limiting.

[0062] Polishing includes mechanical polishing or manual polishing, such as using a six-axis robot for mechanical polishing or manually polishing using a wind mill. Polishing can be performed using a polishing sheet, including but not limited to sandpaper, sponge sand, a thousand-thread wheel 20, and a nylon sheet.

[0063] The parameters such as the mesh size of the grinding disc, grinding speed, grinding time, etc. used in the polishing process can be adjusted according to actual conditions and are not limited here.

[0064] In a specific embodiment, the aluminum extruded workpiece 100 includes a flat plate region and a cylindrical region connected to the flat plate region. The aluminum extruded workpiece 100 has a flat surface 11 , a curved surface 12 , and a connecting surface 13 between the flat surface and the curved surface.

[0065] When polishing the plane 11, first use 240-mesh sandpaper for mechanical polishing, and then use 240-mesh nylon cloth for mechanical polishing. The speed during polishing is 12000 r / min, and the polishing time is 120s-180s.

[0066] See also Figure 3 as well as Figure 4When polishing the connecting surface 13 between the flat surface and the curved surface, a 240-mesh milling wheel 20 is used for mechanical polishing. The polishing speed is 12,000 r / min and the polishing time is 120s-180s. To ensure the polishing effect and effectively remove the aluminum extrusion, the number of blades 21 of the milling wheel 20 is greater than or equal to 20, and the number of blade units 22 contained in each blade 21 is greater than or equal to 10. The blade units 22 on each blade 21 are arranged along the axial direction of the milling wheel 20.

[0067] During the polishing process, the surface of the aluminum extruded workpiece 100 can be polished back and forth along a direction perpendicular to the connection between the plane 11 and the curved surface 12 (see Figure 5 ) That is, the thread wheel 20 moves along the route L1 and the route L2 to perform polishing.

[0068] See also Figure 6 When polishing the curved surface 12, different polishing sheets can be selected for polishing according to the curvature radius of the curved surface 12. For example, for a curved surface 12 with a curvature radius of 4.5 mm, a 240-mesh sponge sand or a 240-mesh nylon cloth can be selected as a polishing sheet. The rotation speed during polishing is 12,000 r / min, and the polishing time is 120s-180s. During the polishing process, the polishing sheet can move back and forth on the curved surface 12 along the axial direction perpendicular to the cylindrical area and roughly along the route L3. It can be understood that the route L3 of each reciprocating motion has a partially overlapping area to ensure that all curved surfaces 12 are polished. In this embodiment, a vibrating wind mill is used for polishing.

[0069] Furthermore, during the polishing process, the pressure applied to the aluminum extruded workpiece 100 during polishing needs to be controlled, for example, the pressure is controlled to be 2.0 N-3.5 N. In a specific embodiment, the pressure is controlled to be 2.5 N.

[0070] Step S5: cleaning and polishing the aluminum extruded workpiece 100.

[0071] The cleaning process includes a degreasing process and a pickling process, and is used to clean dirt such as oil, dust, and aluminum powder from the surface of the aluminum extruded workpiece 100 .

[0072] The degreasing treatment is to use an alkaline cleaning solution to clean the aluminum extruded workpiece 100. The alkaline cleaning solution includes an alkali (such as sodium carbonate, NaOH, etc.), a surfactant (such as fatty alcohol polyoxyethylene ether, thiocarbamide, etc.) and an additive (such as coconut oil fatty acid diethanolamide, trisodium phosphate, sodium bicarbonate, etc.). In a specific embodiment, the alkaline cleaning solution includes sodium carbonate with a volume concentration of 11.39g / mL-12.66g / mL, fatty alcohol polyoxyethylene ether with a volume concentration of 0.82g / mL-1.02g / mL, thiocarbamide with a volume concentration of 0.16g / mL-0.21g / mL and coconut oil fatty acid diethanolamide with a volume concentration of 0.54g / mL-0.68g / mL, and the solvent in the alkaline cleaning solution is water.

[0073] The pickling treatment involves cleaning the aluminum extruded workpiece 100 with a pickling solution. The pickling solution comprises an acid (e.g., nitric acid) at a volume concentration of 1.4-2.1 g / mL and a deashing agent at a concentration of 2.64-3.43 g / mL. The solvent in the pickling solution is water. Furthermore, brighteners, penetrants, and cosolvents may be added to the pickling solution as needed.

[0074] After degreasing and pickling, the aluminum extruded workpiece 100 needs to be cleaned with water to prevent the residual alkaline solution or pickling solution from further corroding the aluminum extruded workpiece 100 and to further clean away the dust, aluminum powder, etc. loaded on the surface of the aluminum extruded workpiece 100.

[0075] In a specific embodiment, a chain-rail cleaning machine is used to sequentially complete the degreasing process and the pickling process. Specifically, the processes are carried out in accordance with the following steps: degreasing, spraying, water washing, spraying, pickling, water washing, spraying, air shearing, and drying. The spraying process can remove dust and aluminum powder with larger particle sizes on the surface of the aluminum extruded workpiece 100; water washing can remove dust and aluminum powder with smaller particle sizes on the surface of the aluminum extruded workpiece 100; air shearing removes dust and aluminum powder on the surface of the aluminum extruded workpiece 100 by blowing cold air; and the drying process can remove residual moisture on the surface of the aluminum extruded workpiece 100, and the drying process temperature is 100°C-120°C. The water used for spraying is recycled, and the pH value of the water after spraying will change due to the residual alkaline or pickling solution on the surface of the aluminum extruded workpiece 100. The pH value of the water after spraying can be controlled to be 4-8 to prevent the pH value of the sprayed water from being too acidic or too alkaline, thereby damaging the surface of the aluminum extruded workpiece 100.

[0076] It is understandable that the above-mentioned cleaning process using a chain track cleaning machine is only an example, and the order or number of spraying or washing can be adjusted as needed.

[0077] Step S6: sandblasting the cleaned aluminum extruded workpiece 100 .

[0078] The sandblasting process involves using compressed air as a power source to form a high-speed jet beam to spray material (e.g., copper ore sand, quartz sand, corundum, iron sand, sea sand, etc.) onto the surface of the aluminum extruded workpiece 100 at high speed, thereby changing the appearance or shape of the surface of the aluminum extruded workpiece 100. The impact and cutting action of the material on the surface of the aluminum extruded workpiece 100 removes burrs and residual impurities (e.g., salt) on the surface of the aluminum extruded workpiece 100. Targeted sandblasting is performed on portions of the aluminum extruded workpiece 100 that are difficult to polish (e.g., the curved surface 12 and the interface 13 between a flat surface and a curved surface) to uniformly roughen the surface of the aluminum extruded workpiece 100. This can also cover any uneven polishing, polishing marks, or minor aluminum extrusion lines that have not been completely removed from the surface of the aluminum extruded workpiece 100.

[0079] The air pressure of the spray gun of the sandblasting equipment, the mesh size of the spray material, and the moving speed of the processed aluminum extruded workpiece 100 can be selected or set according to actual conditions and are not limited.

[0080] In a specific embodiment, the blasting material is 120 mesh and 80 mesh iron sand for sand blasting, and the mass ratio of 120 mesh iron sand to 80 mesh iron sand is 10:3. For the aluminum extruded workpiece 100 with plane 11, the air pressure of the spray gun of the sand blasting equipment is 2.0 kgf / cm 2 -2.2kgf / cm 2 For the aluminum extruded workpiece 100 with a special-shaped surface, the air pressure of the sandblasting equipment is 2.7kgf / cm 2 -2.9kgf / cm 2 ; The moving speed of the aluminum extruded workpiece 100 is 10mm / s-12mm / s.

[0081] Furthermore, after the sandblasting process, the method further includes anodizing and dyeing the aluminum extruded workpiece 100 to form a color layer on the surface of the aluminum extruded workpiece 100 to meet aesthetic requirements.

[0082] The method for removing aluminum extrusion provided in the present application gradually removes the aluminum extrusion marks on the surface of the aluminum extruded workpiece 100 through alkaline etching treatment, black film stripping treatment, polishing treatment, cleaning treatment and sandblasting treatment in sequence. The removal method is simple and low-cost.

[0083] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present application should not depart from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for removing aluminum extrusion, characterized in that: The following steps are involved: Providing an aluminum extrusion workpiece, wherein the surface of the aluminum extrusion workpiece has aluminum extrusion patterns; Placing the aluminum extruded workpiece in an alkaline etching solution containing sodium hydroxide for alkaline etching to remove oil stains and part of the aluminum extrusion lines on the surface of the aluminum extruded workpiece; Placing the aluminum extruded workpiece after the alkaline etching treatment in a bath containing nitric acid for black film stripping treatment to remove the oxide film on the surface of the aluminum extruded workpiece; Polishing the aluminum extruded workpiece after the black film stripping treatment, wherein the polishing treatment includes mechanical polishing or manual polishing to remove the aluminum extrusion lines on the surface of the aluminum extruded workpiece; Cleaning the aluminum extruded workpiece after the polishing treatment, wherein the cleaning treatment includes degreasing and pickling treatment to remove oil, dust and aluminum powder on the surface of the aluminum extruded workpiece; as well as The sandblasting treatment is performed on the aluminum extruded workpiece after the cleaning treatment to remove burrs and residual impurities on the surface of the aluminum extruded workpiece.

2. The method for removing aluminum extrusion according to claim 1, characterized in that: In the alkaline etching step, the concentration of the sodium hydroxide is 50 g / L-70 g / L.

3. The method for removing aluminum extrusion according to claim 2, characterized in that: The temperature of the alkaline etching treatment of the aluminum extruded workpiece in the alkaline etching solution is 57° C.-63° C., and the time of the alkaline etching treatment is 4.5 min-5.5 min.

4. The method for removing aluminum extrusion according to claim 1, characterized in that: In the black film stripping step, the mass fraction of the nitric acid is 5%-10%.

5. The method for removing aluminum extrusion according to claim 1, characterized in that: The aluminum extruded workpiece is polished by using a polishing sheet, wherein the polishing sheet comprises at least one of sandpaper, sponge sand, a milling wheel and a nylon sheet.

6. The method for removing aluminum extrusion according to claim 1, characterized in that: During the polishing process, the pressure applied to the aluminum extrusion workpiece is 2.0N-3.5N.

7. The method for removing aluminum extrusion according to claim 1, characterized in that: The degreasing treatment is to use an alkaline washing solution to clean the aluminum extruded workpiece, and the alkaline washing solution contains an alkali; the pickling treatment is to use an acid washing solution to clean the aluminum extruded workpiece, and the acid washing solution contains an acid.

8. The method for removing aluminum extrusion according to claim 7, characterized in that: After the degreasing treatment and the pickling treatment, spraying treatment is performed respectively, and the pH value of the water used in the spraying treatment is 4-8.

9. The method for removing aluminum extrusion according to claim 1, characterized in that: The surface of the aluminum extruded workpiece includes a flat surface and a shaped surface; for the flat surface, the air pressure during processing is 2.0kgf / cm²-2.2kgf / cm²; for the shaped surface, the air pressure during processing is 2.7kgf / cm²-2.9kgf / cm².

Images