Machining process for combined cooling structure of aluminum alloy shell with plating layer

Abstract

The invention provides a machining process of a combined cooling structure of an aluminum alloy shell with a plating layer, which comprises the following steps of: primary electroplating-turning a matching surface; the method comprises the following steps: removing a plating layer on the surface of a matching surface, cleaning for the first time, pressing, turning a surface to be welded, welding, cleaning for the second time, removing stress in an aging manner, turning a right end surface and a spigot, turning a left end surface and a spigot, milling a water inlet mounting surface, a water outlet mounting surface and threads, cleaning for the third time, electroplating for the second time, testing in a sealing manner and drying. According to the method, coordination of all procedures can be considered, the workpiece quality is guaranteed, the performance and functions of a plating layer are reserved, and the anti-corrosion performance is guaranteed; before the aluminum alloy shell with the plating layer is welded, plating layer removing treatment is carried out on the matched surface, sealing performance inspection is carried out after welding, and welding firmness and consistency are ensured. The seam allowance and the end face are machined and assembled after welding, the product assembling precision is effectively improved, the use requirement of a final product is met, and wide application prospects are achieved.

Description

Technical Field

[0001] The invention relates to a processing technology for a combined cooling structure of an aluminum alloy shell with a coating, and belongs to the technical field of mechanical parts. Background Art

[0002] Aluminum alloy housing combined cooling structures are widely used in high-end equipment due to their low manufacturing costs and ease of implementation. This is particularly true for high-speed motors, where a cooling system is incorporated into the structure to provide system cooling while simultaneously providing system support and corrosion protection. However, existing manufacturing processes for coated aluminum alloy housing combined cooling structures present numerous challenges.

[0003] On the one hand, when combining multiple coated shells into a cooling structure, the traditional processing sequence of welding first and then electroplating can damage the coating at the welded parts, affecting the overall performance of the shells, such as reduced corrosion resistance and the susceptibility to rust at the welded parts. On the other hand, if the individual shells are electroplated first and then combined, the presence of the coating increases the difficulty of welding, making it difficult to ensure welding quality, and is prone to problems such as cold welds and leaks. This results in poor sealing performance of the combined cooling structure, which cannot meet actual use requirements. At the same time, the existing processing technology has a long manufacturing process cycle and is prone to workpiece corrosion. Furthermore, it is often difficult to coordinate the various processes during operations such as shell press-fitting, welding, finishing, and sealing testing. This can easily lead to problems such as coating damage, poor quality of the combined structure, and poor sealing, affecting the performance and service life of the product. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a processing technology for a combined cooling structure of a plated aluminum alloy shell.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention provides a processing technology for a combined cooling structure with a coated aluminum alloy shell, comprising the following steps:

[0007] ① Split electroplating and mating surface treatment: Electroplate shell 1 and shell 2 separately, then lathe the ΦD7 inner hole and the total length L8 of the A surface of shell 1, lathe the press-fit mating surfaces ΦD8, ΦD9 and the depth L8 of the B surface of shell 2, and remove the plating on the mating surfaces;

[0008] ② Press-fit assembly: After cleaning the surfaces of shell 1 and shell 2, press shell 1 vertically into shell 2 along the press-fit direction, so that the A surface of shell 1 and the C surface of shell 2 are completely in contact;

[0009] ③ Weld bead processing and welding: Turn the end faces and outer cylindrical surfaces to be welded of shell 1 and shell 2, mark the joints, and then weld shell 1 and shell 2 along the joints of the end faces and outer cylindrical surfaces to obtain the workpiece;

[0010] Among them, the turning amount of the end surface to be welded is L7, and the diameter of the outer surface to be welded is ΦD6;

[0011] ④ Stress relief and finishing: clean and seal the water inlet and outlet holes, perform aging treatment on the workpiece to eliminate welding stress, then turn the C surface of the right end of the shell 2, and process the inner stoppers of ΦD2 and ΦD3 and the outer stopper of ΦD4, and turn the left end face of the shell 1 and the inner stopper of ΦD1;

[0012] ⑤Interface forming: mill the end faces of the water inlet and outlet holes respectively and process the threads;

[0013] ⑥ Secondary plating and sealing verification: After cleaning the burrs, seal and protect the key surfaces and perform secondary electroplating on the ΦD4 outer diameter stop. Then, pass the test medium through the water inlet hole to detect the sealing of the welding point, and finally dry the workpiece.

[0014] In the steps ① and ⑥, the electroplating is hard anodizing, the coating thickness is 20 to 40 μm, and the surface is sealed after plating.

[0015] In the step ①, ΦD8=ΦD7+(0.02-0.05) mm, ΦD9=ΦD7-(0.02-0.05) mm, so that ΦD7 and ΦD8 form an interference fit, and the ΦD9 segment forms a guide transition.

[0016] In step ②, the housing 1 is heated to 150° C. before press-fitting, kept at this temperature for 30 minutes, and then press-fitted by shrink fitting.

[0017] In step ③, the marking is performed by using a turning tool tip to machine a fine groove with a width of 0.02 mm and a depth of 0.02 to 0.04 mm.

[0018] In the step ③, electron beam welding is used for welding, the end face welding depth is ≥L7+0.5mm, and the outer circle welding depth is ≥(ΦD6-ΦD4) / 2+0.5mm.

[0019] In the step ④, the aging treatment is carried out at 175±5° C. for 3 to 8 hours, and the workpiece is placed vertically in the pressing direction; when turning the ΦD4 outer circle stop, it is aligned with the first electroplated outer circle surface.

[0020] In step ④, the left end face is turned to be positioned with the right end face and the inner hole of ΦD3; in step ⑤, the water inlet end face is milled to be positioned with the right end face and the inner hole of ΦD3, and the water outlet end face is milled to be positioned with the left end face and the inner hole of ΦD1.

[0021] In step ⑥, the secondary electroplating uses a sealing tool with an insulating spacer to seal the inlet and outlet hole bosses, the inner stop and the end face.

[0022] In step ⑥, the sealing test water pressure is ≥8 MPa, and the pressure is maintained for ≥30 minutes.

[0023] The beneficial effects of this invention include: balancing the coordination of various process steps, ensuring workpiece quality, preserving the coating's performance and functionality, and guaranteeing corrosion resistance. The coated aluminum alloy housing undergoes deplating on the mating surfaces before welding, and a post-weld seal inspection ensures weld security and consistency. The post-weld processing of the assembly seams and end faces effectively improves product assembly precision, meeting the requirements of the final product, and possesses broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the front view of the combined cooling structure with a coated aluminum alloy shell;

[0025] Figure 2 This is the left side view of the combined cooling structure with a coated aluminum alloy shell;

[0026] Figure 3 is a flow chart of the present invention;

[0027] Figure 4 It is a structural diagram of the turning mating surface of the housing 1;

[0028] Figure 5 It is a schematic structural diagram of the turning mating surface of the housing 2;

[0029] Figure 6 It is a schematic diagram of the press-fitting of the combined cooling structure with a coated aluminum alloy shell;

[0030] Figure 7 It is a schematic diagram of the lathe turning of the surface to be welded of the combined cooling structure with a coated aluminum alloy shell;

[0031] Figure 8 It is a schematic diagram of the welding of the combined cooling structure with a coated aluminum alloy shell;

[0032] Figure 9 This is a schematic diagram of the turning of the right end face and stop of the combined cooling structure with a coated aluminum alloy shell;

[0033] Figure 10 This is a schematic diagram of the left end face and stopper of the combined cooling structure with a coated aluminum alloy shell;

[0034] Figure 11 This is a schematic diagram of the milling of the water inlet and outlet mounting surfaces and threads of the combined cooling structure with a coated aluminum alloy shell. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0036] Example 1

[0037] like Figures 1 to 11 As shown, the processing technology of the present invention is as follows:

[0038] The first step: electroplating.

[0039] The shells 1 and 2 to be pressed are hard anodized respectively, and the coating thickness is controlled at 20-40 μm. The workpieces are chemically cleaned before plating, and the surfaces are sealed after plating to avoid accumulation of impurities on the surface of the plating oxidation pores.

[0040] Step 2: Turn the mating surface to remove the surface coating.

[0041] Turn the ΦD7 inner hole and A surface of the shell 1 to ensure the total length L8, and remove the sharp edges; turn the press-fitting fitting surfaces ΦD8, ΦD9 and B surface of the shell 2 to ensure the depth L8, remove the surface coating of the fitting surface, ΦD8 = ΦD7 + (0.02 ~ 0.05) mm, ΦD9 = ΦD7 - (0.02 ~ 0.05) mm, clean the root, and remove the sharp edges.

[0042] Step 3: Clean up once.

[0043] Clean the oil and excess materials on the surface of the shell 1 and shell 2, and blow dry or dry the water stains on the surface of the workpiece.

[0044] Step 4: Pressing.

[0045] Heat the shell 1 to 150°C and keep it warm for 30 minutes. Then, press the shell 1 vertically into the shell 2 along the pressing direction using the shrink fit method. Use tooling to ensure the relative positions of the water inlet and outlet holes, and ensure that the A surface of the shell 1 and the C surface of the shell 2 are completely fitted together without any gaps.

[0046] Step 5: Turn the surface to be welded.

[0047] Turn the end face to be welded, remove the surface coating by measuring L7, and remove the sharp edge; turn the outer cylindrical surface to be welded, remove the surface coating to ensure ΦD6, and remove the sharp edge; turn and mark the joints between shell 1 and shell 2, and use the turning tool tip to turn the groove, the groove size is 0.02mm wide and the groove size is 0.02~0.04mm deep.

[0048] Step 6: Soldering.

[0049] Electron beam welding: weld along the joints of the end face and the outer diameter. The end face weld depth should be ≥L7+0.5mm, and the outer diameter weld depth should be ≥(ΦD6-ΦD4) / 2+0.5mm. The end face and outer diameter weld crater depth should be ≤L7. Visually confirm that the weld lines are uniform and there are no leaks or cold welds.

[0050] Step 7: Secondary cleaning.

[0051] Clean the excess materials on the surface of the workpiece and in the hole, use a high-pressure air gun to ventilate and check that the inlet and outlet are not blocked; use a blocking tool to block the inlet and outlet holes, and the installation plane of the blocking tool should be lower than the surface plane of the inlet and outlet bosses.

[0052] Step 8: Aging stress relief.

[0053] Thermal aging treatment eliminates welding stress, keeps the temperature at a fixed temperature of 175±5℃ for 3 to 8 hours, and places the workpiece vertically according to the pressing direction.

[0054] Step 9: Turn the right end face and stop.

[0055] Turn the right end C surface to remove L7 to ensure the distance L4 between the water outlet and the right end surface; turn the ΦD2 and ΦD3 gear internal stops to ensure the depths L3, L2, and L3 roots are cleaned; turn the ΦD4 gear external stop to align it with the plated external surface, and blunt the sharp edges.

[0056] Step 10: Turn the left end face and stop.

[0057] Positioning with the right end face and the ΦD3 inner hole, turn the left end face to remove L7 to ensure the total length L1; turn the ΦD1 inner hole stop to ensure L2, and blunt the sharp edges.

[0058] Step 11: Mill the water inlet and outlet installation surfaces and threads.

[0059] Use the right end face and the ΦD3 inner hole for positioning, mill the end face of the water inlet hole flat to ensure the size of L6, and drill and mill one set of 2-MX threads and 6-MY threads; use the left end face and the ΦD1 inner hole for positioning, mill the end face of the water outlet hole flat to ensure the size of L6, and drill and mill another set of 2-MX threads and 6-MY threads.

[0060] Step 12: Three cleanings. Remove sharp burrs produced by milling; clean the surface and excess materials in the threaded holes;

[0061] Step 13: Secondary electroplating.

[0062] A sealing protection tool is used to seal and protect the inlet and outlet bosses, the inner hole stop and the left and right end surfaces of the workpiece to prevent the electroplating liquid from leaking into the water hole and the inner stop surface. The ΦD4 outer circle is hard anodized and the coating thickness is controlled at 20 to 40 μm. Physical cleaning is used to remove excess surface matter before plating, and the surface is sealed after plating.

[0063] Step 14: Sealing test.

[0064] Let tap water flow through the water inlet, seal the water outlet, set the water pressure to 8 MPa, and keep it for 30 minutes. Observe that there is no leakage at the welding point.

[0065] Step 15: Drying.

[0066] Place the shell combined cooling structure in an oven at a temperature of 100°C for 1 hour to dry the shell.

[0067] Example 2

[0068] Preferably, the primary electroplating and secondary electroplating anodizing treatments are hard anodizing treatments, and the coating thickness is controlled at 20 to 40 μm. The shell assembly is a structural support component, and the interior needs to be resistant to water erosion and meet electrical insulation and corrosion resistance properties. According to the QJ450B selection standard Et·A20~40hd, the coating thickness is 20 to 40 μm, which combines processability and economy.

[0069] Preferably, the primary electroplating and the secondary electroplating adopt anodizing treatment and the surface after plating is sealed to avoid the accumulation of impurities on the surface of the plating oxidation pores.

[0070] Preferably, the workpiece is chemically cleaned before the primary electroplating, and is not chemically cleaned before the secondary electroplating, but is only physically cleaned to remove excess material on the surface.

[0071] Preferably, the mating surface is turned to remove the surface coating ΦD8 = ΦD7 + (0.02 to 0.05) mm, ΦD9 = ΦD7 - (0.02 to 0.05) mm, to ensure that the ΦD9 section forms a guide transition during the press-fitting process and ΦD7 and ΦD8 form an interference fit.

[0072] Preferably, the turning mating surface is marked at the joints between the shell 1 and the shell 2, and the turning tool tip is used to turn the groove. The groove size is 0.02mm wide and 0.02-0.04mm deep. The groove size of this specification will not destroy the structural strength and can clearly show the marking position, while meeting the standard tool tip radius specifications.

[0073] Preferably, before press-fitting, the shell 1 is heated to 150°C and kept warm for 30 minutes, and the shell 1 is pressed into the shell 2 along the press-fitting direction by using the shrink-fit method; according to the interference fit between the shell 2 ΦD8 and the shell 1 ΦD7 of 0.02 to 0.05 mm, the expansion coefficient of conventional aluminum material is about 23.5×10-6 / K. When shrink-fitting at a temperature of 150°C, a gap is formed between the mating surfaces of the shell 2 and the shell 1, thereby achieving convenient assembly. After the shell 1 cools down, it can lock the shell 2 to maintain the shell sealing and the strength of the combined structure; when heated to a temperature of 150°C, the insulation time of 30 minutes is just the time point for the structure to stabilize and the processing cycle is short.

[0074] Preferably, electron beam welding is used for welding, with the end face welding depth being ≥ L7 + 0.5 mm, the outer circle welding depth being ≥ (ΦD6 - ΦD4) / 2 + 0.5 mm, and the end face and outer circle welding arc crater depth being ≤ L7.

[0075] Preferably, the sealing tooling used in the secondary cleaning can withstand the thermal aging temperature, and the installation plane is lower than the surface plane of the inlet and outlet bosses.

[0076] Preferably, the aging treatment is a thermal aging treatment, which is carried out at a fixed temperature of 175±5°C for 3 to 8 hours. Using thermal aging to eliminate stress on the workpiece makes it easier to control the product manufacturing cycle and ensure the aging effect. The aging temperature of conventional aluminum materials is 150 to 180°C, and there are processing errors in aging furnaces. A fixed temperature of 175±5°C for 3 to 8 hours can meet the accuracy of domestic treatment furnaces and achieve a complete aging effect, thereby decomposing the supersaturated solid solution in the workpiece to eliminate internal stress, while stabilizing the structure and size and improving mechanical properties.

[0077] Preferably, the right end face and the stop are turned so that the outer circle of ΦD4 is flush with the plated outer circle surface.

[0078] Preferably, the left end face and the stop are turned, and the right end face and the inner hole of ΦD3 are used for positioning.

[0079] Preferably, when milling the water inlet and outlet mounting surfaces and the thread to flatten the water inlet end face, use the right end face and the inner hole of ΦD3 for positioning; when milling the water outlet end face, use the left end face and the inner hole of ΦD1 for positioning.

[0080] Preferably, the secondary electroplating closed protection adopts a sealed protective tooling, and an insulating spacer is provided between the protective tooling and the workpiece to prevent the conductive discharge and ablation between the protective tooling and the workpiece.

[0081] Preferably, the sealing test is conducted by introducing tap water from the water inlet, blocking the water outlet, setting the water pressure to ≥8 MPa, and lasting for ≥30 minutes, and observing whether there is leakage at the weld. Depending on the workpiece conditions, the test accuracy can be guaranteed under such water pressure conditions.

[0082] Preferably, the shell combined cooling structure is placed in an oven for drying at a temperature of 80-120°C for a holding time of ≥1h; this temperature condition can be achieved by most ovens, and at the same time, the liquid water stains in the cooling tank can be released outward in the form of steam under this temperature condition, and it is not sufficient to change the internal crystal structure of the workpiece.

Claims

1. A process for processing a combined cooling structure with a coated aluminum alloy shell, characterized in that: The following steps are involved: ① Split electroplating and mating surface treatment: Electroplate shell 1 and shell 2 separately, then lathe the ΦD7 inner hole and the total length L8 of the A surface of shell 1, lathe the press-fit mating surfaces ΦD8, ΦD9 and the depth L8 of the B surface of shell 2, and remove the plating on the mating surfaces; ② Press-fit assembly: After cleaning the surfaces of shell 1 and shell 2, press shell 1 vertically into shell 2 along the press-fit direction, so that the A surface of shell 1 and the C surface of shell 2 are completely in contact; ③ Weld bead processing and welding: Turn the end faces and outer cylindrical surfaces to be welded of shell 1 and shell 2, mark the joints, and then weld shell 1 and shell 2 along the joints of the end faces and outer cylindrical surfaces to obtain the workpiece; Among them, the turning amount of the end surface to be welded is L7, and the diameter of the outer surface to be welded is ΦD6; ④ Stress relief and finishing: clean and seal the water inlet and outlet holes, perform aging treatment on the workpiece to eliminate welding stress, then turn the C surface of the right end of the shell 2, and process the inner stoppers of ΦD2 and ΦD3 and the outer stopper of ΦD4, and turn the left end face of the shell 1 and the inner stopper of ΦD1; ⑤Interface forming: mill the end faces of the water inlet and outlet holes respectively and process the threads; ⑥ Secondary plating and sealing verification: After cleaning the burrs, seal and protect the key surfaces and perform secondary electroplating on the ΦD4 outer diameter stop. Then, pass the test medium through the water inlet hole to detect the sealing of the welding point, and finally dry the workpiece.

2. The processing technology of the combined cooling structure of the coated aluminum alloy shell according to claim 1, characterized in that: In the steps ① and ⑥, the electroplating is hard anodizing, the coating thickness is 20 to 40 μm, and the surface is sealed after plating.

3. The processing technology of the combined cooling structure of the coated aluminum alloy shell according to claim 1, characterized in that: In the step ①, ΦD8=ΦD7+(0.02-0.05) mm, ΦD9=ΦD7-(0.02-0.05) mm, so that ΦD7 and ΦD8 form an interference fit, and the ΦD9 segment forms a guide transition.

4. The processing technology of the combined cooling structure of the coated aluminum alloy shell according to claim 1, characterized in that: In step ②, the housing 1 is heated to 150° C. before press-fitting, kept at this temperature for 30 minutes, and then press-fitted by shrink fitting.

5. The processing technology of the combined cooling structure of the coated aluminum alloy shell according to claim 1, characterized in that: In step ③, the marking is performed by using a turning tool tip to machine a fine groove with a width of 0.02 mm and a depth of 0.02 to 0.04 mm.

6. The processing technology of the combined cooling structure of the coated aluminum alloy shell according to claim 1, characterized in that: In the step ③, electron beam welding is used for welding, the end face welding depth is ≥L7+0.5mm, and the outer circle welding depth is ≥(ΦD6-ΦD4) / 2+0.5mm.

7. The processing technology of the combined cooling structure of the coated aluminum alloy shell according to claim 1, characterized in that: In the step ④, the aging treatment is carried out at 175±5° C. for 3 to 8 hours, and the workpiece is placed vertically in the pressing direction; when turning the ΦD4 outer circle stop, it is aligned with the first electroplated outer circle surface.

8. The processing technology of the combined cooling structure of the coated aluminum alloy shell according to claim 1, characterized in that: In step ④, the left end face is turned to be positioned with the right end face and the inner hole of ΦD3; in step ⑤, the water inlet end face is milled to be positioned with the right end face and the inner hole of ΦD3, and the water outlet end face is milled to be positioned with the left end face and the inner hole of ΦD1.

9. The processing technology of the combined cooling structure of the coated aluminum alloy shell according to claim 1, characterized in that: In step ⑥, the secondary electroplating uses a sealing tool with an insulating spacer to seal the inlet and outlet hole bosses, the inner stop and the end face.

10. The processing technology of the combined cooling structure of the plated aluminum alloy shell according to claim 1, characterized in that: In step ⑥, the sealing test water pressure is ≥8 MPa, and the pressure is maintained for ≥30 minutes.

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