Surface treatment method for universally machining ADC12 special-shaped aluminum die-casting workpiece

Abstract

The invention discloses a surface treatment method for universally processing an ADC12 special-shaped aluminum die-casting workpiece, and particularly aims at a special-shaped structure aluminum die-casting workpiece which cannot directly adopt mechanical automatic processing, the automatic processing of special-shaped aluminum workpiece surface treatment is realized by integrating processes of 3D laser, sand blasting, dust removal, anodic oxidation, hole sealing and paint spraying and the like. The problems that traditional manual grinding is low in efficiency, high in defective rate and insufficient in corrosion resistance are effectively solved. Compared with the prior art, through technological parameter optimization and process integration, the machining efficiency and quality of the special-shaped aluminum workpiece are remarkably improved, the surface color uniformity, the metal brightness and the corrosion resistance are remarkably improved, and the method is suitable for small-batch automatic production requirements.

Description

Technical Field

[0001] The invention relates to the technical field of surface treatment of aluminum die-casting workpieces, in particular to a surface treatment method for universally processing ADC12 special-shaped aluminum die-casting workpieces. Background Art

[0002] The existing anodizing process for special-shaped aluminum die-castings has numerous shortcomings. Due to the irregular shapes of aluminum die-castings, surface treatment relies solely on manual grinding, which is difficult, inefficient, and results in high defective rates. Furthermore, existing pore sealing methods struggle to meet specific requirements for corrosion and weather resistance, necessitating improvements. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an anodic treatment process for special-shaped die-cast aluminum workpieces, so as to realize the automated processing of special-shaped aluminum workpieces, reduce manual work, improve processing efficiency and processing quality, and be suitable for small-batch automated surface processing of ADC12 special-shaped aluminum die-cast workpieces.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: a surface treatment method for universal processing ADC12 special-shaped aluminum die-casting workpiece, comprising the following steps:

[0005] Step S1: providing an ADC12 special-shaped die-cast aluminum workpiece with a special-shaped structure that cannot be directly processed by mechanized automatic processing;

[0006] Step S2, 3D laser surface treatment, sending each ADC12 special-shaped die-cast aluminum workpiece to a 3D laser machine for batch peeling treatment, and the peeling depth is controlled at 50-100 μm;

[0007] Step S3: transferring the ADC12 special-shaped die-cast aluminum workpiece to a sandblasting device for sandblasting;

[0008] Step S4: Deashing: sending the ADC12 special-shaped die-cast aluminum workpiece to a deashing tank for immersion for 5 to 8 seconds;

[0009] Step S5, anodizing, sending the ADC12 special-shaped die-cast aluminum workpiece after dust removal to an anodizing tank for immersion and anodizing treatment;

[0010] Step S6: sealing and spray painting, spray painting the ADC12 special-shaped die-cast aluminum workpiece after anodizing;

[0011] The surface structure of the surface-machined ADC12 special-shaped aluminum die-casting workpiece includes a combination of protrusions, depressions and / or free-form surfaces.

[0012] In a further technical solution, the 3D laser surface treatment includes the following sub-steps:

[0013] S2.1) Place the ADC12 special-shaped die-cast aluminum workpiece within the laser range;

[0014] S2.2) Test the depth by trial striking. The initial trial striking depth is set at 75μm-85μm. Test the laser equipment at different depths by increasing or decreasing the energy.

[0015] S2.3) Visually inspect the test area to determine if the color is uniform. After the first test, if the color of the test area is uniform, conduct a reduced test with a depth of 10 μm each time until the color of the test area becomes uneven. The depth of the last test is used as the full laser shooting depth. After the first test, if the color of the test area is uneven, conduct an incremental test with a depth of 15 μm each time until the color of the test area is uniform. The depth of the last test is used as the full laser shooting depth.

[0016] S2.3) Determine the overall laser penetration depth and use this value to perform 3D laser surface treatment on the entire ADC12 special-shaped die-cast aluminum workpiece.

[0017] In a further technical solution, in step S3, the sandblasting pressure is 3-4KG, the sandblasting roughness is 80# steel sand, and the surface of the aluminum workpiece is sandblasted.

[0018] In a further technical solution, the deashing tank in the deashing step is filled with a deashing solution, which includes nitric acid, hydrofluoric acid and tap water, with a mass ratio of 10-13%:5%:85-82%. The temperature of the reagent in the deashing tank is controlled at 20℃-28℃, and the soaking time is 5-8S.

[0019] In a further technical solution, in step S5, the anodizing tank is filled with a sulfuric acid mixture, which contains filtered water and sulfuric acid in a mass ratio, and the concentration of sulfuric acid in the sulfuric acid mixture is 180-220 g / L; when performing anodizing treatment, the temperature of the sulfuric acid mixture is maintained at 21.5-23°C, the immersion time is 3300-3600s, and the voltage is 13-14.5V.

[0020] In a further technical solution, in the sealing spray painting step, a mixed paint liquid is used for spraying, wherein the mixed paint liquid includes acrylic polyurethane topcoat and curing agent in a ratio of 10:0.5~1; the spraying time is 10~15 seconds, and the spraying thickness is 5-15μm. The formed paint film has the characteristics of high gloss and high fullness. The interface between the paint film and the aluminum workpiece is characterized by adhesion 5B and excellent salt spray resistance.

[0021] Compared with the prior art, the present invention has the following advantages: the present invention realizes the automated processing of special-shaped aluminum workpieces, reduces manual work, improves processing efficiency and processing quality, makes the surface color of special-shaped aluminum castings more uniform and beautiful, has metallic brightness and better corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings and examples.

[0023] Figure 1 1 is a flow chart of the surface treatment method of the present invention.

[0024] Figure 2 It is a sub-step diagram of the 3D laser surface processing steps in the present invention. DETAILED DESCRIPTION

[0025] The following are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

[0026] The surface structure of the anodized special-shaped die-cast aluminum workpiece of the present invention includes a combination of protrusions, depressions and / or free-form surfaces. If it is processed only by the existing anodizing process, the surface will have problems such as uneven color and lack of metallic luster.

[0027] ADC12 special-shaped aluminum die-casting workpieces are irregularly shaped with various concave and convex parts. They have complex shapes and structures and many processing dead angles. It is impossible to use general processing equipment to realize automated machining of all kinds of workpieces. Unless corresponding "special machining equipment" is specially designed and prepared for each workpiece, automated machining can be realized. This is unrealistic for small-batch diversified automated machining. The "special machining equipment" designed and manufactured for each workpiece must go through the equipment scheme design, manufacturing of "special machining equipment", debugging and trial production, etc., which generally takes several months or longer. That is, the pre-preparation cycle is extremely long, and this pre-preparation also has design failures, unstable trial production quality, and prone to failures in the small-batch production process. The comprehensive processing cost is much higher than the traditional manual grinding processing method, and the total processing cycle, risk and unreliability are also much higher than the traditional manual grinding processing method. The lengthy pre-preparation and the resulting increased unreliability, risk and processing cost are unacceptable to both parties to the commissioned processing.

[0028] ADC12, also known as No. 12 aluminum, is a Japanese aluminum alloy. It's a die-cast aluminum alloy based on the Al-Si-Cu system and is suitable for applications such as cylinder head covers, sensor brackets, and cylinder blocks. It complies with JIS H 5302-2006, "Aluminum Alloy Die Castings." ADC12 is equivalent to the Chinese alloy code YL113, with the alloy designation YZAlSi11Cu3 and the GB / T 15115-2009 standard.

[0029] Therefore, the inventors have proposed an anodizing process for special-shaped die-cast aluminum workpieces. This embodiment is an improved anodizing process for aluminum die-castings with irregular contours. It can overcome the shortcomings of the existing technology, so that the surface of aluminum die-castings with irregular contours can be processed to have a uniform and beautiful color, and its processing efficiency can be improved, eliminating the need for artificial surface grinding, and making the surface have a metallic luster.

[0030] like Figure 1 and Figure 2 As shown, the present invention provides a surface treatment method for a universal ADC12 special-shaped aluminum die-casting workpiece, comprising the following steps:

[0031] Step S1: providing an ADC12 special-shaped die-cast aluminum workpiece with a special-shaped structure that cannot be directly processed by mechanized automatic processing;

[0032] Step S2, 3D laser surface treatment, respectively, sends each ADC12 special-shaped die-cast aluminum workpiece to the 3D laser machine for batch peeling treatment, and the peeling depth is controlled at 50-100 μm. Among them, the 3D laser surface treatment includes the following sub-steps:

[0033] S2.1) Place the ADC12 special-shaped die-cast aluminum workpiece within the laser range;

[0034] S2.2) Test the depth by trial striking. The initial trial striking depth is set at 75μm-85μm. Test the laser equipment at different depths by increasing or decreasing the energy.

[0035] S2.3) Visually inspect the test area to determine if the color is uniform. After the first test, if the color of the test area is uniform, conduct a reduced test with a depth of 10 μm each time until the color of the test area becomes uneven. The depth of the last test is used as the full laser shooting depth. After the first test, if the color of the test area is uneven, conduct an incremental test with a depth of 15 μm each time until the color of the test area is uniform. The depth of the last test is used as the full laser shooting depth.

[0036] S2.4) Confirm the full laser drilling depth and use this value to perform 3D laser surface treatment on the entire ADC12 special-shaped die-cast aluminum workpiece;

[0037] Step S3: transfer the ADC12 special-shaped die-cast aluminum workpiece into a sandblasting device for sandblasting. The sandblasting pressure is 3.5 kg and the sandblasting roughness is 80 steel grit.

[0038] Step S4: Deashing: sending the ADC12 special-shaped die-cast aluminum workpiece to a deashing tank for immersion for 7 seconds;

[0039] Step S5, anodizing, sending the ADC12 special-shaped die-cast aluminum workpiece after dust removal to an anodizing tank for immersion and anodizing treatment;

[0040] Step S6: sealing and spray painting, spray painting the ADC12 special-shaped die-cast aluminum workpiece after anodizing;

[0041] The surface structure of the ADC12 special-shaped aluminum die-casting workpiece subjected to surface processing includes a combination of protrusions, depressions and / or free-form surfaces.

[0042] Specifically, the deashing pool in the deashing step is filled with a deashing solution, which includes nitric acid, hydrofluoric acid and tap water, with a mass ratio of 10-13%:5%:85-82%. The temperature of the reagent in the deashing pool is controlled at 20°C-28°C, and the soaking time is 5-8S.

[0043] Specifically, in step S5, the anodizing tank is filled with a sulfuric acid mixture, which contains filtered water and sulfuric acid in a mass ratio, and the concentration of sulfuric acid in the sulfuric acid mixture is 180-220 g / L; when performing the anodizing treatment, the temperature of the sulfuric acid mixture is maintained at 21.5-23°C, the immersion time is 3300-3600s, and the voltage is 13-14.5V.

[0044] Specifically, in the sealing spray painting step, a mixed paint liquid is used for spray painting, wherein the mixed paint liquid includes acrylic polyurethane topcoat and curing agent, and the ratio thereof is 10:0.5-1; the spraying time is 10-15 seconds, and the spraying thickness is 5-15 μm. The formed paint film has the characteristics of high gloss and high fullness. The interface between the paint film and the aluminum workpiece is characterized by adhesion 5B and excellent salt spray resistance.

[0045] Specifically, step S6 also includes the following sub-steps:

[0046] S6.1, oiling: dilute the varnish in proportion, mix and stir for 5-10 minutes, and filter through a 200-300 mesh filter;

[0047] S6.2, Spraying: Use an air spray gun, adjust the air pressure to 0.3-0.5 MPa, adjust the spray width to fan shape, and test spray to ensure uniform atomization;

[0048] S6.3. Keep the spray gun 15 to 25 cm away from the substrate, move at a constant speed (30 to 50 cm / s), and spray vertically;

[0049] S6.4. For single spraying, move at a constant speed in the same direction, overlapping the spraying area by 1 / 3 to 1 / 2 to avoid spraying omissions or dripping.

[0050] Since the surface structure of the ADC12 special-shaped aluminum die-cast workpiece includes a combination of protrusions, depressions and / or free-form surfaces, manual grinding is extremely inconvenient and difficult, and it is difficult to perform efficient surface peeling treatment. Therefore, the inventors combined 3D laser surface processing technology to peel the surface of the ADC12 special-shaped aluminum die-cast workpiece, which not only enables rapid batch processing, but also has good peeling effect and uniform base color.

[0051] The surface treatment of ADC12 special-shaped aluminum die-casting workpieces processed by the traditional anodizing process and the process of the present invention is carried out to obtain the following performance comparison table:

[0052]

[0053] Table 1

[0054] The present invention achieves a quantitative improvement of more than 50% in efficiency, quality and weather resistance through parameter standardization, automated processes and material ratio optimization. It is particularly suitable for the production of special-shaped aluminum workpieces with high precision and high weather resistance requirements.

[0055] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there may be changes in the specific implementation methods and application scopes. The contents of this specification should not be understood as limiting the present invention.

Claims

1. A surface treatment method for general processing ADC12 special-shaped aluminum die-casting workpieces, characterized in that: The following steps are involved: Step S1: providing an ADC12 special-shaped die-cast aluminum workpiece with a special-shaped structure that cannot be directly processed by mechanized automatic processing; Step S2, 3D laser surface treatment, sending each ADC12 special-shaped die-cast aluminum workpiece to a 3D laser machine for batch peeling treatment, and the peeling depth is controlled at 50-100 μm; Step S3: transferring the ADC12 special-shaped die-cast aluminum workpiece to a sandblasting device for sandblasting; Step S4: Deashing: sending the ADC12 special-shaped die-cast aluminum workpiece to a deashing tank for immersion for 5 to 8 seconds; Step S5, anodizing, sending the ADC12 special-shaped die-cast aluminum workpiece after dust removal to an anodizing tank for immersion and anodizing treatment; Step S6: sealing and spray painting, spray painting the ADC12 special-shaped die-cast aluminum workpiece after anodizing; The surface structure of the ADC12 special-shaped aluminum die-casting workpiece subjected to surface processing includes a combination of protrusions, depressions and / or free-form surfaces.

2. The surface treatment method for a general-purpose ADC12 special-shaped aluminum die-casting workpiece according to claim 1 is characterized in that: The 3D laser surface processing includes the following sub-steps: S2.1) Place the ADC12 special-shaped die-cast aluminum workpiece within the laser range; S2.2) Test the depth by trial striking. The initial trial striking depth is set at 75μm-85μm. Test the laser equipment at different depths by increasing or decreasing the energy. S2.3) Visually inspect the test area to determine if the color is uniform. After the first test, if the color of the test area is uniform, conduct a reduced test with a depth of 10 μm each time until the color of the test area becomes uneven. The depth of the last test is used as the full laser shooting depth. After the first test, if the color of the test area is uneven, conduct an incremental test with a depth of 15 μm each time until the color of the test area is uniform. The depth of the last test is used as the full laser shooting depth. S2.3) Determine the overall laser penetration depth and use this value to perform 3D laser surface treatment on the entire ADC12 special-shaped die-cast aluminum workpiece.

3. The surface treatment method for a general-purpose ADC12 special-shaped aluminum die-casting workpiece according to claim 2, characterized in that: In step S3, the sandblasting pressure is 3-4 kg and the sandblasting roughness is 80# steel sand.

4. The surface treatment method for a general-purpose ADC12 special-shaped aluminum die-casting workpiece according to claim 1, characterized in that: The deashing tank in the deashing step is filled with a deashing solution, which includes nitric acid, hydrofluoric acid and tap water in a mass ratio of 10-13%:5%:85-82%. The temperature of the reagent in the deashing tank is controlled at 20°C-28°C, and the soaking time is 5-8S.

5. The surface treatment method for a general-purpose ADC12 special-shaped aluminum die-casting workpiece according to claim 1, characterized in that: In step S5, the anodizing tank is filled with a sulfuric acid mixture, which contains filtered water and sulfuric acid in a mass ratio, and the concentration of sulfuric acid in the sulfuric acid mixture is 180-220 g / L; when performing the anodizing treatment, the temperature of the sulfuric acid mixture is maintained at 21.5-23°C, the immersion time is 3300-3600s, and the voltage is 13-14.5V.

6. The surface treatment method for a general-purpose ADC12 special-shaped aluminum die-casting workpiece according to claim 1, characterized in that: In the sealing spray painting step, a mixed paint liquid is used for spraying, wherein the mixed paint liquid includes acrylic polyurethane topcoat and curing agent in a ratio of 10:0.5-1; the spraying time is 10-15 seconds, and the spraying thickness is 5-15 μm.

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