Cleaning and testing methods for flow channels in 3D printed aluminum alloy engine mounting brackets

Abstract

The present invention discloses a method for cleaning and inspecting the inner flow channel of a 3D-printed aluminum alloy engine mounting bracket. The method first uses clean compressed air to remove powder, then uses ultrasonic cleaning to remove powder after X-ray inspection, repeatedly ultrasonically cleans and rinses with high-pressure water after machining the blank, then performs alkaline cleaning (pickling), then abrasive flow polishing, then uses water jet treatment, then rinses with clean deionized water and detects excess matter, then blows off excess matter with high-purity nitrogen to achieve further cleaning and excess matter detection, and finally uses clean deionized water rinsing and excess matter detection after vibration and clean high-purity nitrogen to blow off excess matter detection. The present invention solves the problems of incomplete cleaning of excess matter in the complex inner flow channel of the 3D aluminum alloy engine mounting bracket, powder sticking to the flow channel surface, and cleaning of slag, thereby ensuring the product cleanliness quality of the 3D-printed aluminum alloy engine mounting bracket.

Description

Technical Field

[0001] The present invention belongs to the field of 3D printing technology, and in particular to a method for cleaning and detecting excess matter in a complex inner flow channel of a 3D-printed aluminum alloy engine mounting bracket. Background Art

[0002] The 3D-printed aluminum alloy engine mounting bracket is manufactured using a laser-laid metal powder bed selective fusion (SLM) process. Due to the characteristics of the production process, its internal flow channels are subject to powder sticking and slag. To simultaneously meet the engine's fuel, oxidizer, and control gas supply requirements, the 3D-printed aluminum alloy engine mounting bracket has a complex internal flow channel design, manifested in a three-dimensional serpentine pattern. This makes it difficult to remove powder sticking and slag from the internal flow channel surface during the molding process. Furthermore, there is a risk of excess particles falling during subsequent use. These particles will remain inside the product, forming excess debris, which can cause problems such as clogging the engine valves, seriously affecting normal engine operation.

[0003] At present, there are three main methods for cleaning residual powder in the flow channel of products during 3D printing: ultrasonic cleaning, compressed air blowing and high-pressure water washing.

[0004] Ultrasonic cleaning is to fully immerse the product in the cleaning liquid for cleaning. Because the powder and slag on the inner surface of the inner flow channel have adhesion to the substrate, ultrasonic cleaning can only remove completely unmelted metal powder on the surface of the product and the inner surface of the flow channel, and is not effective in cleaning powder and slag on the inner surface of the flow channel.

[0005] Compressed air blow-off involves injecting compressed air into the inlet of the 3D-printed part and blowing out the metal powder from the outlet. This long-term blow-off removes excess powder from the flow channel of the 3D-printed aluminum alloy engine mounting bracket. This method can only remove completely unmelted metal powder from the surface of the part and the inner surface of the flow channel. It is not very effective for cleaning powder and slag on the inner surface of the flow channel.

[0006] High-pressure water flushing involves injecting high-pressure water into the inlet of the 3D-printed product and then flowing it out through each outlet one by one. This long flushing process removes excess powder from the flow channels of the 3D-printed aluminum alloy engine mounting bracket. However, this cleaning method has the following drawbacks: Due to the complex flow channels within the 3D-printed aluminum alloy engine mounting bracket, the water pressure, flow rate, and flow resistance within these complex channels are inconsistent, making it less effective in cleaning powder and residue from the inner surface of the channels.

[0007] In summary, no matter which of the above methods or a combination of any two or even three methods is used, the problem of cleaning the inner flow channel of the 3D printed aluminum alloy engine mounting bracket cannot be solved. When airflow is used to simulate fuel, oxidizer or control gas to pass into the inner flow channel, the outflow of excess matter (sticky powder, hanging slag) can still be detected at the airflow outlet (for example, 1MPa gas is used to blow the flow channel for 2 minutes, and the dust-free cloth at the outlet is inspected with a magnifying glass, and visible excess matter is found. After detection, it is found that the excess matter is caused by sticky powder and hanging slag falling from the surface of the inner flow channel). Summary of the Invention

[0008] In order to solve the above problems, the present invention aims to provide a method for cleaning and inspecting the flow channels inside a 3D-printed aluminum alloy engine mounting bracket, thereby solving the problems of powder sticking and slag not being cleaned thoroughly in the internal flow channels of existing 3D-printed aluminum alloy products, thereby eliminating the risk of excess particles falling during use and avoiding the problem of excess particles remaining inside the product and forming blockages.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] The cleaning and inspection method of the flow channel in the 3D printed aluminum alloy engine mounting bracket includes:

[0011] Step 1: Lay metal powder on a powder bed and use laser selective melting to process a 3D printed aluminum alloy engine mounting bracket blank;

[0012] Step 2: Use clean compressed air to blow away the metal powder on the surface of the 3D printed aluminum alloy engine mounting bracket blank;

[0013] Inject clean compressed air into the inlet of the 3D printed aluminum alloy engine mounting bracket blank and blow it out until no powder is blown out of the outlet;

[0014] Inject clean compressed air into the outlet of the 3D printed aluminum alloy engine mounting bracket blank and blow it out until no powder is blown out of the inlet;

[0015] Step 3: Use X-ray to detect whether there is powder residue or other defects inside the 3D printed aluminum alloy engine mounting bracket blank;

[0016] Step 4: annealing the 3D printed aluminum alloy engine mounting bracket blank;

[0017] Step 5: Completely immerse the 3D printed aluminum alloy engine mounting bracket blank in deionized water for ultrasonic cleaning.

[0018] Step 6: Completely seal all inlets and outlets of the 3D printed aluminum alloy engine mounting bracket blank and sandblast the surface of the blank to ensure that there is no sticky powder, slag or excess material on the surface;

[0019] Step 7: Finish-machine all inlets, outlets, and mounting surfaces of the 3D printed aluminum alloy engine mounting bracket blank, and install process nozzles at all inlets and outlets.

[0020] Step 8, repeat step 5 above;

[0021] Step 9: Use high-pressure water to flush the 3D printed aluminum alloy engine mounting bracket from its inlet;

[0022] Use high-pressure water to flush from the outlet of the 3D printed aluminum alloy engine mounting bracket;

[0023] Step 10: Inject the prepared alkali solution into the flow channel of the 3D printed aluminum alloy engine mounting bracket to completely fill the flow channel. Each flow channel is alkali-washed for a preset time and immediately rinsed with high-pressure water after alkali washing.

[0024] Step 11: Inject the prepared pickling solution into the flow channel of the 3D printed aluminum alloy engine mounting bracket to completely fill the flow channel. Each flow channel is pickled for a preset time. Immediately after pickling, rinse with high-pressure water. After rinsing, test the pH value. If the pH value is equal to 7, it is qualified. If it is unqualified, continue cleaning until it is qualified.

[0025] Step 12, performing abrasive flow polishing on the inner flow channel of the 3D printed aluminum alloy engine mounting bracket;

[0026] Step 13, flushing the inner flow channel with high-pressure water to clean the remaining abrasive in the inner flow channel;

[0027] Step 14: Perform water jet treatment on the inner flow channel of the 3D printed aluminum alloy engine mounting bracket;

[0028] Step 15: flush the inner flow channel with high-pressure water to clean the remaining abrasive in the inner flow channel;

[0029] Step 16: Completely immerse the 3D printed aluminum alloy engine mounting bracket in deionized water for ultrasonic cleaning.

[0030] Step 17: Inject clean deionized water from the inlet of the 3D printed aluminum alloy engine mounting bracket to flush the internal flow channel, and perform a cleanliness test on the deionized water after flushing. The deionized water cleanliness test here refers to sampling the deionized water after flushing and testing it with an oil particle size detector;

[0031] Step 18: vacuum drying the cleaned 3D printed aluminum alloy engine mounting bracket;

[0032] In step 19, inject clean high-purity nitrogen gas from the inlet of the 3D printed aluminum alloy engine mounting bracket, wrap a clean dust-free cloth around the outlet, blow the flow channel with gas, and then inspect the dust-free cloth with a magnifying glass. No visible excess material should be on the dust-free cloth.

[0033] Step 20: Place the 3D printed aluminum alloy engine mounting bracket on a vibration table and perform random vibration in the X, Y, and Z directions. Repeat step 19 after the vibration is complete.

[0034] Step 21, repeat step 17;

[0035] Step 22, repeat step 18.

[0036] As an option,

[0037] Between step 2 and step 3, the inner flow channel is further subjected to quartz sand vibration polishing and compressed air blowing. Quartz sand is added to the inner flow channel, the 3D printed aluminum alloy engine mounting bracket is fixed on the vibration table while the 3D printed aluminum alloy engine mounting bracket is kept rotating, and then the quartz sand is blown away with clean compressed air;

[0038] Between step 9 and step 10, the inner flow channel abrasive flow polishing and high-pressure water flushing are also performed in sequence, and the abrasive of the abrasive flow is flushed clean by high-pressure water after the abrasive flow polishing;

[0039] After step 22, the process also includes scanning the inner flow channel with CT to detect the residual amount of excess matter.

[0040] Furthermore, the steps 2, 5, 8, 9, 13, 14, 15 and 16 are repeated no less than 3 times.

[0041] Furthermore, in step 2, the compressed air used for cleaning the powder is clean, oil-free and water-free compressed air.

[0042] Furthermore, in step 5, step 8, and step 16, the ultrasonic cleaning time is 1 hour to 2 hours.

[0043] Furthermore, in steps 9, 13, and 15, high-pressure water is used to flush the flow channel inlet and outlet of the 3D printed aluminum alloy engine mounting bracket, and each flushing time is 8 minutes.

[0044] Furthermore, in step 10, new alkali solution is added every once in a while.

[0045] Furthermore, in step 11, 20% dilute nitric acid is used for pickling, and dilute nitric acid is continuously added during pickling.

[0046] further,

[0047] In step 12, the abrasive used in the abrasive flow polishing is CSi particles, the abrasive flow polishing pressure is 8 MPa, and the polishing time is 25 minutes;

[0048] In step 14, the abrasive used in the water jet treatment is CSi particles, the water jet pressure is 0.4 MPa, and the flushing time is 1 minute;

[0049] In step 17, the deionized water used in the flushing and excess material detection needs to be filtered through a filter or a filter membrane, and the cleanliness is one level higher than the product cleanliness. The flushing pressure is 0.5 MPa and the flushing time is 2 minutes.

[0050] Furthermore, in step 18, the rinsed 3D printed aluminum alloy engine mounting bracket is dried in a vacuum oven at a temperature of 60° C. for 6 hours.

[0051] Furthermore, in step 19 and step 21, the high-purity nitrogen is used after passing through a filter.

[0052] Compared with the prior art, the present invention has the following advantages:

[0053] (1) Based on the traditional ultrasonic cleaning, compressed air blowing and high-pressure water flushing, the present invention selects a method of alkali cleaning + abrasive flow + vibration post-cleanliness detection based on the characteristics of the inner flow channel of the 3D printed aluminum alloy engine mounting bracket, and reasonably arranges the order of ultrasonic cleaning, compressed air blowing, high-pressure water flushing, alkali cleaning, acid cleaning, abrasive flow, and vibration post-detection, eliminating the problems of powder sticking and slag hanging in the inner flow channel;

[0054] (2) After the inner flow channel is polished with alkaline washing, the rough powder on the surface of the inner flow channel can be washed away, and the rough surface of the inner flow channel is significantly refined, without any sticky powder, slag, protrusions, etc. The surface quality of the inner flow channel is significantly improved. The purpose of acid washing is to neutralize the alkalinity; and after the inner flow channel is polished with abrasive flow, no protrusions, sticky powder, or slag are found on the surface of the flow channel, and the rough surface is significantly improved. Alkaline washing + abrasive flow has a significant effect and can completely clean the special structure of the inner flow channel of the 3D printed aluminum alloy engine mounting bracket.

[0055] (3) The present invention uses a variety of detection methods while cleaning the inner flow channel, such as using an oil particle size detector to detect the cleanliness of the high-pressure water used to flush the inner flow channel, observing the excess matter on the dust-free cloth with a magnifying glass at the outlet, and detecting the residue in the inner flow channel through CT. At the same time, the present invention introduces a vibration test method for assessment (detection of excess matter before vibration and detection of excess matter after vibration) to simulate the working conditions of the 3D printed aluminum alloy engine mounting bracket. The combination of multiple methods can accurately determine whether there is any residue in the inner flow channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic diagram of a 3D printed aluminum alloy engine mounting bracket according to the present invention. DETAILED DESCRIPTION

[0057] The present invention is further described below with reference to the accompanying drawings and specific implementation examples, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following implementation examples. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0058] In this embodiment, Figure 1 The 3D printed aluminum alloy engine mounting bracket shown in the figure provides a method for cleaning and detecting excess material in the complex internal flow channel of the 3D printed aluminum alloy engine mounting bracket, which specifically includes the following steps:

[0059] The first step is to 3D print the aluminum alloy engine mounting bracket blank:

[0060] 3D printed aluminum alloy engine mounting bracket blanks were produced by laying metal powder on a powder bed and using Selective Laser Melting (SLM).

[0061] Step 2: Clear powder:

[0062] Use clean compressed air to blow away the metal powder on the surface of the 3D printed aluminum alloy engine mounting bracket blank;

[0063] Inject clean compressed air into the inlet of the 3D printed aluminum alloy engine mounting bracket blank and blow it out until no powder is blown out of the outlet;

[0064] Inject clean compressed air into the outlet of the 3D printed aluminum alloy engine mounting bracket blank and blow it out until no powder is blown out of the inlet;

[0065] As an optional option, after completing the aforementioned powder cleaning process, you can also use quartz sand vibration polishing, followed by blowing away the quartz sand with clean compressed air. To do this, add quartz sand to the internal flow channel of the part, secure the part on a vibration cleaning table, and keep the part rotating for 5 hours at a frequency of 200Hz. Quartz sand vibration polishing can remove fine needle-like particles from the surface of the internal flow channel, providing a certain polishing effect, but it cannot completely eliminate the problem of slag.

[0066] The third step is X-ray detection:

[0067] Use X-rays to inspect the interior of the 3D-printed aluminum alloy engine mounting bracket blank for residual powder or other defects.

[0068] Step 4: Heat treatment:

[0069] Annealing treatment of 3D printed aluminum alloy engine mounting bracket blank.

[0070] Step 5: Ultrasonic cleaning;

[0071] The 3D printed aluminum alloy engine mounting bracket blank was completely immersed in deionized water for ultrasonic cleaning;

[0072] Step 6: Surface sandblasting:

[0073] Completely block all inlets and outlets of the 3D printed aluminum alloy engine mounting bracket blank with cloth strips, and sandblast the surface of the part to ensure that there is no sticky powder, slag or excess material on the surface;

[0074] Step 7: machining;

[0075] All inlets, outlets and mounting surfaces of the 3D printed aluminum alloy engine mounting bracket blank are machined and process nozzles are installed at all inlets and outlets;

[0076] Step 8: Ultrasonic cleaning:

[0077] Repeat step 5 above;

[0078] Step 9: High-pressure water cleaning:

[0079] Turn on the high-pressure pump and use 1MPa high-pressure water to flush the 3D printed aluminum alloy engine mounting bracket from the inlet; use 1MPa high-pressure water to flush the 3D printed aluminum alloy engine mounting bracket from the outlet;

[0080] As an option, after completing the above high-pressure water cleaning step, you can add an abrasive flow polishing (the polishing time is halved compared to the abrasive flow polishing time in the twelfth step, which can be understood as rough polishing), and then high-pressure water cleaning (to rinse away the abrasives in the abrasive flow). This cleaning effect will be better.

[0081] Step 10, alkaline washing:

[0082] Inject the prepared alkali solution into the flow channel of the 3D printed aluminum alloy engine mounting bracket to completely fill the flow channel. The alkali cleaning time for each flow channel is 10 minutes. After the alkali cleaning, immediately rinse with 1MPa high-pressure water for 5 minutes.

[0083] Step 11: Pickling:

[0084] Inject the prepared pickling liquid into the flow channel of the 3D printed aluminum alloy engine mounting bracket to completely fill the flow channel. The pickling time for each flow channel is 2 minutes, and then immediately rinse with 1MPa high-pressure water for 20 minutes. Test the pH value. If the pH value is 7, it is judged to be qualified. If it is unqualified, continue cleaning until it is qualified.

[0085] Step 12: Abrasive flow polishing:

[0086] Abrasive flow polishing of the inner flow channel of a 3D printed aluminum alloy engine mounting bracket;

[0087] Step 13: High-pressure water cleaning:

[0088] Turn on the high-pressure pump and flush the inner flow channel with 1MPa high-pressure water to clean the remaining abrasive in the inner flow channel;

[0089] Step 14: Water jet treatment:

[0090] Perform water jet treatment on the flow channels inside the 3D printed aluminum alloy engine mounting bracket;

[0091] Step 15: High-pressure water cleaning:

[0092] Turn on the high-pressure pump and flush the inner flow channel with 1MPa high-pressure water to clean the remaining abrasive in the inner flow channel;

[0093] Step 16, ultrasonic cleaning:

[0094] The 3D printed aluminum alloy engine mounting bracket was completely immersed in deionized water for ultrasonic cleaning;

[0095] Step 17: Rinse and detect excess material:

[0096] Inject clean deionized water from the inlet of the 3D printed aluminum alloy engine mounting bracket to flush the internal flow channel, and then test the cleanliness of the deionized water after flushing.

[0097] Step 18: Drying:

[0098] The cleaned 3D printed aluminum alloy engine mounting bracket is vacuum dried;

[0099] Step 19: Excess material removal test:

[0100] Inject clean high-purity nitrogen gas from the inlet of the 3D-printed aluminum alloy engine mounting bracket, wrap a clean dust-free cloth around the outlet, and blow the flow channel with 1MPa gas for 2 minutes. Use a magnifying glass to inspect the dust-free cloth to ensure no visible excess matter.

[0101] Step 20: Vibration detection:

[0102] Place the 3D printed aluminum alloy engine mounting bracket on a vibration table and perform random vibration in the X, Y, and Z directions at a frequency of 100Hz to 2000Hz for 3 to 5 minutes. After the vibration is complete, repeat "Step 19, Excess Material Blowing and Testing."

[0103] Step 21: Cleaning and excess material detection:

[0104] Repeat step 17 above;

[0105] Step 22: Drying:

[0106] Repeat step 18 above;

[0107] If conditions permit, CT scanning can be used after step 22 to scan the excess material inside the part to achieve complete inspection.

[0108] The second step, the fifth step, the eighth step, the ninth step, the thirteenth step, the fourteenth step, the fifteenth step, and the sixteenth step are repeated no less than three times.

[0109] The compressed air used in the second step of powder cleaning is clean, oil-free and water-free compressed air.

[0110] The time for ultrasonic cleaning in the fifth, eighth and sixteenth steps is 1 to 2 hours.

[0111] In the ninth, thirteenth and fifteenth steps, high-pressure water is used to flush the inlet and outlet of the 3D printed aluminum alloy engine mounting bracket, and each flushing time is 8 minutes.

[0112] In the tenth step, a certain amount of new alkali solution is added every 2 minutes during the alkali washing process.

[0113] In the eleventh step, 20% dilute nitric acid is used in the pickling, and the dilute nitric acid is continuously added during the pickling.

[0114] In the twelfth step, the abrasive used in the abrasive flow polishing is CSi particles, the abrasive flow polishing pressure is 8 MPa, and the polishing time is 25 minutes.

[0115] In the fourteenth step, the abrasive used in the water jet treatment is CSi particles, the water jet pressure is 0.4 MPa, and the flushing time is 1 minute.

[0116] In the seventeenth step, rinsing and excess material detection, the deionized water used is filtered through a filter or filter membrane, and the cleanliness is one level higher than the product cleanliness. The rinsing pressure is 0.5MPa and the rinsing time is 2 minutes.

[0117] In the eighteenth step, the washed 3D printed aluminum alloy engine mounting bracket is dried in a vacuum oven at a temperature of 60° C. for 6 hours.

[0118] In the nineteenth and twenty-first steps of the excess material removal test, the high-purity nitrogen gas is used after passing through a filter, and the cleanliness meets the technical requirements.

[0119] The cleaning and testing method described above is a comprehensive approach for the flow within a 3D-printed aluminum alloy engine mounting bracket. It takes into account the structural characteristics of the parts, the material characteristics, and the specific characteristics of the molding process during the printing process. Only by fully executing these steps can the surface problems of powder adhesion, slag, and protrusions be completely eliminated, ensuring that the inner surface of the internal flow is free of protrusions, powder adhesion, and slag, with significantly improved surface roughness. Furthermore, a composite testing method is employed: firstly, the internal flow channel is flushed with clean deionized water, and the cleanliness of the final flush deionized water is tested using an oil particle size detector; secondly, an excess material is blown away for testing, facilitating redundant control and timely problem detection.

Claims

1. A method for cleaning and inspecting the flow passages within a 3D-printed aluminum alloy engine mounting bracket, characterized by: include, Step 1: Lay metal powder on a powder bed and use laser selective melting to process a 3D printed aluminum alloy engine mounting bracket blank; Step 2: Use clean compressed air to blow away the metal powder on the surface of the 3D printed aluminum alloy engine mounting bracket blank; Inject clean compressed air into the inlet of the 3D printed aluminum alloy engine mounting bracket blank and blow it out until no powder is blown out of the outlet; Inject clean compressed air into the outlet of the 3D printed aluminum alloy engine mounting bracket blank and blow it out until no powder is blown out of the inlet; Step 3: Perform quartz sand vibration polishing and compressed air blowing on the inner flow channel in sequence. Add quartz sand to the inner flow channel, fix the 3D printed aluminum alloy engine mounting bracket blank on the vibration table while keeping the 3D printed aluminum alloy engine mounting bracket blank rotating, and then use clean compressed air to blow away the quartz sand. Step 4: Use X-ray to inspect whether there is powder residue or other defects inside the 3D printed aluminum alloy engine mounting bracket blank; Step 5: annealing the 3D printed aluminum alloy engine mounting bracket blank; Step 6: Completely immerse the 3D printed aluminum alloy engine mounting bracket blank in deionized water for ultrasonic cleaning. Step 7: Completely seal all inlets and outlets of the 3D printed aluminum alloy engine mounting bracket blank and sandblast the blank surface to ensure that there is no sticky powder, slag or excess material on the surface. Step 8: Finish-machine all inlets, outlets, and mounting surfaces of the 3D printed aluminum alloy engine mounting bracket blank, and install process nozzles at all inlets and outlets. Step 9, repeat step 6 above; Step 10: Use high-pressure water to inject and rinse from the inlet of the 3D printed aluminum alloy engine mounting bracket blank; Use high-pressure water to inject and flush from the outlet of the 3D printed aluminum alloy engine mounting bracket blank; Step 11, sequentially performing abrasive flow polishing and high-pressure water flushing of the inner flow channel, after which the abrasive flow is flushed clean by high-pressure water; Step 12: Inject the prepared alkali solution into the flow channel of the 3D printed aluminum alloy engine mounting bracket blank to completely fill the flow channel. Each flow channel is alkali-washed for 10 minutes and then immediately rinsed with high-pressure water. Step 13: Inject the prepared pickling solution into the flow channel of the 3D printed aluminum alloy engine mounting bracket blank to completely fill the flow channel. Each flow channel is pickled for 2 minutes. After pickling, it is immediately rinsed with high-pressure water. After rinsing, the pH value is tested. If the pH value is equal to 7, it is qualified. If it is unqualified, continue to rinse until it is qualified. Step 14, performing abrasive flow polishing on the inner flow channel of the 3D printed aluminum alloy engine mounting bracket blank; Step 15: flush the inner flow channel with high-pressure water to clean the remaining abrasive in the inner flow channel; Step 16: performing water jet treatment on the inner flow channel of the 3D printed aluminum alloy engine mounting bracket blank; Step 17: flush the inner flow channel with high-pressure water to clean the remaining abrasive in the inner flow channel; Step 18: completely immerse the 3D printed aluminum alloy engine mounting bracket blank in deionized water for ultrasonic cleaning; Step 19: Inject clean deionized water from the inlet of the 3D printed aluminum alloy engine mounting bracket blank to flush the inner flow channel, and perform a cleanliness test on the deionized water after flushing; Step 20: vacuum drying the cleaned 3D printed aluminum alloy engine mounting bracket blank; Step 21: Inject clean high-purity nitrogen gas into the inlet of the 3D-printed aluminum alloy engine mounting bracket blank, wrap a clean dust-free cloth around the outlet, and blow the flow channel with gas. Then, inspect the dust-free cloth with a magnifying glass to ensure that no visible excess matter is present on the cloth. Step 22: Place the 3D printed aluminum alloy engine mounting bracket blank on a vibration table and perform random vibration in the X, Y, and Z directions. Repeat step 21 after the vibration is complete. Step 23, repeat step 19; Step 24, repeat step 20; Step 25: Scan the inner flow channel with CT to detect the residual excess material.

2. The method for cleaning and inspecting the flow passage inside a 3D printed aluminum alloy engine mounting bracket according to claim 1, characterized in that: In step 2, the compressed air used for cleaning the powder is clean, oil-free and water-free compressed air.

3. The method for cleaning and inspecting the flow passage in a 3D printed aluminum alloy engine mounting bracket according to claim 1, characterized in that: In step 6, step 9 and step 18, the ultrasonic cleaning time is 1 hour to 2 hours.

4. The method for cleaning and inspecting the flow passage in a 3D printed aluminum alloy engine mounting bracket according to claim 1, characterized in that: In steps 10, 15, and 17, high-pressure water is used to flush the flow channel inlet and outlet of the 3D printed aluminum alloy engine mounting bracket blank, and each flushing time is 8 minutes.

5. The method for cleaning and inspecting the flow passage inside a 3D printed aluminum alloy engine mounting bracket according to claim 1, characterized in that: In the step 12, new alkali solution is added every once in a while.

6. The method for cleaning and inspecting the flow passage in a 3D printed aluminum alloy engine mounting bracket according to claim 1, characterized in that: In step 13, 20% dilute nitric acid is used for pickling, and dilute nitric acid is continuously added during pickling.

7. The method for cleaning and inspecting the flow passage in a 3D printed aluminum alloy engine mounting bracket according to claim 1, characterized in that: In step 14, the abrasive used in the abrasive flow polishing is CSi particles, the abrasive flow polishing pressure is 8 MPa, and the polishing time is 25 minutes; In step 16, the abrasive used in the water jet treatment is CSi particles, the water jet pressure is 0.4 MPa, and the flushing time is 1 minute; In step 19, the deionized water used in the flushing and excess material detection needs to be filtered through a filter or a filter membrane, and the cleanliness is one level higher than the product cleanliness. The flushing pressure is 0.5 MPa and the flushing time is 2 minutes.

8. The method for cleaning and inspecting the flow passage in a 3D printed aluminum alloy engine mounting bracket according to claim 1, characterized in that: In step 20, the washed 3D printed aluminum alloy engine mounting bracket blank is dried in a vacuum oven at a temperature of 60° C. for 6 hours.

9. The method for cleaning and inspecting the flow passage in a 3D printed aluminum alloy engine mounting bracket according to claim 1, characterized in that: In steps 21 and 22, the high-purity nitrogen is used after passing through a filter.

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