Online rework process flow of aluminum alloy appearance defective product for automobile trim

Abstract

The present application belongs to the technical field of alloy material processing, and particularly relates to an online rework process flow of aluminum alloy appearance defective products for automobile trim. The online rework process flow comprises acid etching or paint stripping, film stripping, pickling, electrochemical polishing, secondary film stripping, secondary pickling and anodic oxidation. The process of stripping the oxidation film of defective products is optimized accordingly. After the acid etching or paint stripping, film stripping and pickling processes, the defective products are subjected to drying treatment and anodic oxidation, and do not need to be subjected to mechanical polishing or manual polishing treatment, thereby saving the rework cost, shortening the rework process and time, promoting the rapid circulation of defective products, reducing the stagnation of defective products, effectively improving the appearance defects of defective products and reducing the defective product rate.

Description

Technical Field

[0001] This invention belongs to the field of alloy material processing technology, specifically relating to an online rework process for aluminum alloy products with defective appearance used in automotive trim. Background Technology

[0002] Automotive aluminum alloy decorative trim strips are increasingly favored by car buyers due to their high gloss, good metallic texture, smooth surface, light weight, and excellent corrosion resistance. High standards are placed on their appearance; even minor defects such as scratches, impurities, and color differences are considered defective. The common method for handling these defective products is to remove the oxide film layer from the surface for rework, followed by mechanical or manual polishing to improve the smoothness and gloss of the entire surface. Finally, anodizing is performed. The specific process includes: oxide film removal and mounting, acid etching, oxide film removal, acid pickling, oxide film removal and mounting, mechanical polishing, manual polishing, anodizing mounting, anodizing process input, and mounting inspection. However, this method consumes polishing machine output, increases labor and energy consumption, resulting in significant production costs. It also increases the number of rework steps, extends turnaround time, and affects product delivery. Summary of the Invention

[0003] The purpose of this invention is to address the above-mentioned technical problems by providing an online rework process for aluminum alloy automotive trim products with defective appearance. This process involves finely adjusting the oxide film removal and anodizing processes to balance the two steps and achieve a polish-free process for defective products.

[0004] The online rework process for aluminum alloy automotive trim products with poor appearance in this invention includes acid etching or paint stripping, film removal, pickling, electrochemical polishing, secondary film removal, secondary pickling, and anodizing.

[0005] When product defects include polishing lines, color difference, spots, watermarks, oxide film cracks, scratches, scratches at subsequent work stations, etc., the online rework process includes acid etching, film removal, pickling and anodizing.

[0006] When product defects include polishing lines, color difference, spots, watermarks, oxide film cracks, scratches, scratches from subsequent processes, flow marks, bluing, whitening, bright spots, grains, etc., the online rework process includes paint stripping, film removal, acid washing, and anodizing.

[0007] This invention optimizes the process for removing the oxide film from defective products. After acid etching or paint stripping, film removal, and acid washing, the defective products are dried and then anodized. This eliminates the need for mechanical or manual polishing, saving rework costs, shortening the rework process and time, and promoting rapid turnover of defective products, reducing their stagnation. However, the anodizing process parameters need adjustment. If the parameters deviate from the range or the selected process is inappropriate, the oxide film removal solution will exhibit defects such as whitening, roughness, and low gloss, failing to meet appearance requirements.

[0008] Furthermore, the etching bath solution is an ammonium bifluoride (NH4HF2) solution with a concentration of 20–50 g / L, an etching temperature of 20–50 °C, and an etching time of 50–100 s.

[0009] Furthermore, the paint stripping solution is a water-soluble paint remover, the paint stripping temperature is 50-70℃, and the paint stripping time is 100-200s.

[0010] Furthermore, the stripping bath solution is a sodium hydroxide (NaOH) solution with a sodium hydroxide concentration of 30–50 g / L, the stripping temperature is 20–50 °C, and the stripping time is 50–100 s.

[0011] Furthermore, the pickling solution is a sulfuric acid solution (H2SO4), with a sulfuric acid concentration of 150–200 g / L, a pickling temperature of 20–50 °C, and a pickling time of 50–100 s.

[0012] Furthermore, the solution used for electrochemical polishing is H2SO4, H3PO4, and Al. 3+ A mixed aqueous solution with H2SO4 concentration of 350–450 g / L, H3PO4 concentration of 750–850 g / L, and Al 3+ The concentration is 25–39 g / L.

[0013] Furthermore, the electrochemical polishing voltage is 35–40V, and the time is 1500–2000s.

[0014] Furthermore, the bath solution for the secondary stripping includes a mixture of sodium dodecylbenzenesulfonate, citric acid, or one or both with sodium hydroxide, with a sodium hydroxide concentration of 20–30 g / L, a secondary stripping temperature of 20–50 °C, and a time of 50–100 s.

[0015] Furthermore, the secondary pickling bath consists of sulfuric acid solution and hydrogen peroxide, with the sulfuric acid solution concentration being 150–200 g / L, the secondary pickling temperature being 20–50 °C, and the time being 50–100 s.

[0016] Furthermore, the solution used for anodizing is H2SO4 and Al. 3+A mixed aqueous solution containing sulfuric acid concentration of 100–200 g / L, Al 3+ The concentration is 5.0–10.0 g / L.

[0017] Furthermore, the anodizing voltage is 15–20V, and the time is 1500–2000s.

[0018] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0019] (1) The online rework process of the present invention can effectively improve the appearance defects of defective products and reduce the defect rate of products;

[0020] (2) The online rework process of the present invention uses electrochemical polishing, which reduces the roughness of the product surface and obtains a brighter and smoother product surface;

[0021] (3) The online rework process of the present invention avoids traditional mechanical polishing and manual polishing, reduces the energy consumption and personnel input of mechanical polishing equipment, shortens the rework process and time, and reduces the rework cost of defective products. Detailed Implementation

[0022] The technical solution of the present invention will be further described and illustrated below through specific embodiments. It should be understood that the specific embodiments described herein are only for the purpose of helping to understand the present invention and are not intended to limit the present invention. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used raw materials in the art, and the methods used in the embodiments are all conventional methods in the art.

[0023] Example 1

[0024] This example demonstrates the online rework process for aluminum alloy automotive trim products with traditional sealed matte finishes that have defects, including the following steps:

[0025] (1) The defective products are hung up and immersed in the acid etching tank solution for acid etching treatment. The acid etching tank solution is NH4HF2 solution with a concentration of 25g / L, the temperature is 45℃, and the time is 60S. After acid etching, the products are washed with water.

[0026] (2) Perform oxide film removal treatment. The oxide film removal tank solution is NaOH solution with a concentration of 50g / L, a temperature of 50℃, and a time of 80S. After the oxide film is removed, wash off the residual solution on the product surface with water.

[0027] (3) Pickling: The pickling solution is H2SO4 with a concentration of 200g / L, a temperature of 20℃, and a time of 50s. After pickling, the residual solution on the product surface is washed away with water and then dried.

[0028] (4) Electrochemical polishing treatment. The electrochemical polishing solution contains H2SO4, H3PO4, aluminum sulfate, and H2O, with H2SO4 concentration of 450 g / L, H3PO4 concentration of 850 g / L, and Al... 3+ The concentration was 35 g / L, the electrochemical polishing voltage was 37 V, and the time was 1800 s;

[0029] (5) The second oxide film removal was carried out using AKE206 from Ningbo Hanyi Chemical Co., Ltd., with a sodium hydroxide concentration of 30 g / L, a temperature of 50°C, and a time of 80 seconds. After water washing, a second acid wash was carried out using Z820 from Shanghai Ruiteliang Chemical Co., Ltd., with a sulfuric acid concentration of 180 g / L, a temperature of 20°C, and a time of 50 seconds. Water washing was also carried out.

[0030] (6) Anodizing treatment, the anodizing solution contains H2SO4 and Al. 3+ The oxidation process involved H2O, with sulfuric acid concentration of 200 g / L, aluminum sulfate concentration of 8 g / L, oxidation voltage of 16 V, and time of 1800 s.

[0031] (7) After washing and sealing, the product is dried, then hung for inspection, assembled, and shipped.

[0032] Example 2

[0033] This example demonstrates the online rework process for aluminum alloy automotive trim products with traditional sealed matte finishes that have defects, including the following steps:

[0034] (1) The defective products are hung up and immersed in the acid etching tank solution for acid etching treatment. The acid etching tank solution is NH4HF2 solution with a concentration of 30g / L, the temperature is 40℃, and the time is 70S. After acid etching, the products are washed with water.

[0035] (2) Perform oxide film removal treatment. The oxide film removal tank solution is NaOH solution with a concentration of 45g / L, a temperature of 40℃, and a time of 100s. After the oxide film is removed, wash off the residual solution on the product surface with water.

[0036] (3) Pickling: The pickling solution is H2SO4 with a concentration of 180g / L, a temperature of 30℃, and a time of 80s. After pickling, the residual solution on the product surface is washed away with water and then dried.

[0037] (4) Electrochemical polishing treatment. The electrochemical polishing solution contains H2SO4, H3PO4, aluminum sulfate, and H2O, with H2SO4 concentration of 400 g / L, H3PO4 concentration of 800 g / L, and Al... 3+ The concentration was 36 g / L, the electrochemical polishing voltage was 38 V, and the time was 1600 s;

[0038] (5) The second oxide film removal is performed in the bath solution AKE206, the sodium hydroxide concentration is 25g / L, the temperature is 50℃, and the time is 80S. After water washing, the second acid washing is performed in the bath solution Z820, the sulfuric acid concentration is 180g / L, the temperature is 20℃, and the time is 50S. After water washing, the second acid washing is performed.

[0039] (6) Anodizing treatment, the anodizing solution contains H2SO4 and Al. 3+ The oxidation process involved H2O, with sulfuric acid concentration of 180 g / L, aluminum sulfate concentration of 7 g / L, oxidation voltage of 17 V, and time of 1900 s.

[0040] (7) After washing and sealing, the product is dried, then hung for inspection, assembled, and shipped.

[0041] Example 3

[0042] This example demonstrates the online rework process for aluminum alloy automotive trim products with traditional sealed matte finishes that have defects, including the following steps:

[0043] (1) The defective products are hung up and immersed in the acid etching tank solution for acid etching treatment. The acid etching tank solution is NH4HF2 solution with a concentration of 35g / L, the temperature is 30℃, and the time is 100S. After acid etching, the products are washed with water.

[0044] (2) Perform oxide film removal treatment. The oxide film removal tank solution is NaOH solution with a concentration of 40g / L, a temperature of 45℃, and a time of 80S. After the oxide film is removed, wash off the residual solution on the product surface with water.

[0045] (3) Pickling: The pickling solution is H2SO4 with a concentration of 160g / L, a temperature of 40℃, and a time of 60s. After pickling, the residual solution on the product surface is washed away with water and then dried.

[0046] (4) Electrochemical polishing treatment. The electrochemical polishing solution contains H2SO4, H3PO4, aluminum sulfate, and H2O, with H2SO4 concentration of 350 g / L, H3PO4 concentration of 760 g / L, and Al... 3+ The concentration was 38 g / L, the electrochemical polishing voltage was 40 V, and the time was 1800 s;

[0047] (5) The second oxide film removal is performed in the AKE206 bath with a sodium hydroxide concentration of 30 g / L, a temperature of 50°C, and a time of 80 s. After water washing, the second acid washing is performed in the Z820 bath with a sulfuric acid concentration of 170 g / L, a temperature of 20°C, and a time of 50 s. After water washing, the second acid washing is performed.

[0048] (6) Anodizing treatment, the anodizing solution contains H2SO4 and Al. 3+The oxidation process involved H2O, with sulfuric acid concentration of 160 g / L, aluminum sulfate concentration of 9 g / L, oxidation voltage of 18 V, and time of 2000 s.

[0049] (7) After washing and sealing, the product is dried, then hung for inspection, assembled, and shipped.

[0050] Example 4

[0051] The difference between this embodiment and embodiment 1 is only that step (1) involves immersing the defective product in a paint stripping tank for paint stripping treatment. The paint stripping solution is MA3-RP500 from Shanghai Ruiteliang Chemical Co., Ltd. The paint stripping temperature is 60℃ and the time is 60S. After the paint is stripped, the product is washed with water.

[0052] Example 5

[0053] The only difference between this embodiment and embodiment 1 is that in step (1), the acid etching bath solution is an NH4HF2 solution with a concentration of 10 g / L, the temperature is 45°C, the time is 60 s, and the solution is washed with water after acid etching.

[0054] Example 6

[0055] The only difference between this embodiment and embodiment 1 is that in step (1), the acid etching bath solution is an NH4HF2 solution with a concentration of 60 g / L, the temperature is 45°C, the time is 60 s, and the solution is washed with water after acid etching.

[0056] Example 7

[0057] The only difference between this embodiment and embodiment 1 is that in step (1), the acid etching bath solution is an NH4HF2 solution with a concentration of 25g / L, the temperature is 10℃, the time is 60S, and the solution is washed with water after acid etching.

[0058] Example 8

[0059] The only difference between this embodiment and embodiment 1 is that in step (1), the acid etching bath solution is an NH4HF2 solution with a concentration of 25 g / L, the temperature is 60°C, the time is 60 seconds, and the solution is washed with water after acid etching.

[0060] Example 9

[0061] The only difference between this embodiment and Embodiment 1 is that in step (2), the oxide film removal bath solution is a NaOH solution with a concentration of 10 g / L, a temperature of 50°C, and a time of 80 seconds.

[0062] Example 10

[0063] The only difference between this embodiment and Embodiment 1 is that in step (2), the oxide film removal bath solution is a NaOH solution with a concentration of 60 g / L, a temperature of 50°C, and a time of 80 seconds.

[0064] Example 11

[0065] The only difference between this embodiment and embodiment 1 is that in step (2), the oxide film removal bath solution is a NaOH solution with a concentration of 50 g / L, a temperature of 10°C, and a time of 80 s.

[0066] Example 12

[0067] The only difference between this embodiment and embodiment 1 is that in step (2), the oxide film removal bath solution is a NaOH solution with a concentration of 50 g / L, a temperature of 60°C, and a time of 80 seconds.

[0068] Example 13

[0069] The only difference between this embodiment and embodiment 1 is that in step (3), the pickling solution is H2SO4 with a concentration of 130 g / L, a temperature of 40°C, and a time of 60 seconds.

[0070] Example 14

[0071] The only difference between this embodiment and embodiment 1 is that in step (3), the pickling solution is H2SO4 with a concentration of 220 g / L, a temperature of 40°C, and a time of 60 seconds.

[0072] Example 15

[0073] The only difference between this embodiment and embodiment 1 is that in step (3), the pickling solution is H2SO4 with a concentration of 160 g / L, a temperature of 10°C, and a time of 60 seconds.

[0074] Example 16

[0075] The only difference between this embodiment and embodiment 1 is that in step (3), the pickling solution is H2SO4 with a concentration of 160 g / L, a temperature of 60°C, and a time of 60 seconds.

[0076] Example 17

[0077] The only difference between this embodiment and Example 1 is that the electrochemical polishing solution in step (4) contains H2SO4, H3PO4, and Al. 3+ The mixture consisted of H2O, with H2SO4 concentration of 300 g / L, H3PO4 concentration of 850 g / L, aluminum sulfate concentration of 35 g / L, electrochemical polishing voltage of 37 V, and time of 1800 s.

[0078] Example 18

[0079] The only difference between this embodiment and Example 1 is that the electrochemical polishing solution in step (4) contains H2SO4, H3PO4, and Al. 3+The mixture consisted of H2O, with H2SO4 concentration of 500 g / L, H3PO4 concentration of 850 g / L, aluminum sulfate concentration of 35 g / L, electrochemical polishing voltage of 37 V, and time of 1800 s.

[0080] Example 19

[0081] The only difference between this embodiment and Example 1 is that the electrochemical polishing solution in step (4) contains H2SO4, H3PO4, and Al. 3+ The mixture consisted of H2O, with H2SO4 concentration of 450 g / L, H3PO4 concentration of 850 g / L, aluminum sulfate concentration of 20 g / L, electrochemical polishing voltage of 37 V, and time of 1800 s.

[0082] Example 20

[0083] The only difference between this embodiment and Example 1 is that the electrochemical polishing solution in step (4) contains H2SO4, H3PO4, and Al. 3+ The mixture consisted of H2O, with H2SO4 concentration of 450 g / L, H3PO4 concentration of 850 g / L, aluminum sulfate concentration of 45 g / L, electrochemical polishing voltage of 37 V, and time of 1800 s.

[0084] Example 21

[0085] The only difference between this embodiment and Embodiment 1 is that the sulfuric acid concentration in step (6) anodic oxidation is 50 g / L, Al 3+ The concentration was 8 g / L, the oxidation voltage was 16 V, and the time was 1800 s.

[0086] Example 22

[0087] The only difference between this embodiment and Embodiment 1 is that the sulfuric acid concentration in step (6) anodic oxidation is 250 g / L, Al 3+ The concentration was 8 g / L, the oxidation voltage was 16 V, and the time was 1800 s.

[0088] Example 23

[0089] The only difference between this embodiment and Embodiment 1 is that in step (6) anodic oxidation treatment, the sulfuric acid concentration is 200 g / L, the aluminum sulfate concentration is 15 g / L, the oxidation voltage is 16 V, and the time is 1800 s.

[0090] Example 24

[0091] The only difference between this embodiment and Embodiment 1 is that in step (6) anodic oxidation treatment, the sulfuric acid concentration is 200 g / L, the aluminum sulfate concentration is 1 g / L, the oxidation voltage is 16 V, and the time is 1800 s.

[0092] In Examples 1-4, the reworked products showed relatively good appearance repair with no surface defects. In Examples 5-8, when the temperature and concentration were below this standard, the electrophoretic layer on the product surface could not be completely removed; when the temperature and concentration were above this standard, the product would exhibit roughness defects. In Examples 9-12, when the temperature and concentration were below this standard, the sealing layer on the product surface could not be destroyed, resulting in poor film removal and impurity defects; when the temperature and concentration were above this standard, the product would exhibit roughness defects. In Examples 13-16, when the temperature and concentration were below this standard, the oxide film on the product surface could not be completely removed; when the temperature and concentration were above this standard... The product will exhibit roughness defects when the standard is met; in Examples 17-20, when the temperature and concentration are below the standard, the black and gray substances on the product surface cannot be completely removed, and when the temperature and concentration are above the standard, the product surface will be corroded, resulting in corrosion pit defects; in Examples 21-22, when the aluminum sulfate concentration is below the standard, the product will exhibit roughness defects; when the temperature, concentration, and time are above the standard, the product will exhibit whitening defects; in Examples 23-24, when the sulfuric acid concentration is above the standard, the product will exhibit excessive film thickness and dull gloss; when the sulfuric acid concentration is below the standard, the film thickness will be too low and the gloss will be too high.

[0093] Finally, it should be noted that the specific embodiments described herein are merely illustrative of the spirit of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. An online rework process for aluminum alloy automotive trim products with defective appearance, characterized in that, This includes acid etching, film stripping, pickling, electrochemical polishing, secondary film stripping, secondary pickling, and anodizing; The etching bath solution is ammonium bifluoride solution with a concentration of 20~50 g / L, an etching temperature of 20~50℃, and an etching time of 50~100 s; The stripping bath solution is a sodium hydroxide solution with a sodium hydroxide concentration of 40~50g / L, the stripping temperature is 40~50℃, and the stripping time is 80~100s; The solutions used for electrochemical polishing are H2SO4, H3PO4, and Al. 3+ A mixed aqueous solution with H2SO4 concentration of 350-450 g / L, H3PO4 concentration of 750-850 g / L, and Al 3+ The concentration was 25~39 g / L, the electrochemical polishing voltage was 35~40 V, and the time was 1500~2000 s; The bath solution for the secondary stripping is a mixed solution of AKE206 and sodium hydroxide produced by Ningbo Hanyi Chemical Co., Ltd., with a sodium hydroxide concentration of 20~30g / L. The secondary stripping temperature is 20~50℃ and the time is 50~100s. The secondary pickling solution consists of Z820 produced by Shanghai Ruiteliang Chemical Co., Ltd. and sulfuric acid solution. The concentration of sulfuric acid solution is 150~200g / L. The secondary pickling temperature is 20~50℃ and the time is 50~100s.

2. The online rework process according to claim 1, characterized in that, The pickling solution is a sulfuric acid solution with a concentration of 150~200g / L. The pickling temperature is 20~50℃ and the pickling time is 50~100s.

3. The online rework process according to claim 1, characterized in that, The solution used for anodizing is H2SO4 and Al. 3+ A mixed aqueous solution containing sulfuric acid concentration of 100-200 g / L and Al 3+ The concentration is 5.0~10.0 g / L.

4. The online rework process according to claim 1, characterized in that, The anodizing voltage is 15~20V, and the time is 1500~2000s.