Magnetic particle grinding and finishing machining method for inner surface of fuel manifold in additive manufacturing

Abstract

The invention discloses a magnetic particle grinding and finishing machining method for the inner surface of an additive manufacturing fuel manifold. The method comprises the steps that machining equipment is assembled; blocking an oil outlet of the fuel oil header pipe; filling a magnetic grinding particle medium, plugging an oil inlet of a fuel oil main pipe, and installing the fuel oil main pipe to processing equipment to finish the addition of the aqueous grinding fluid; inclining the fuel oil header pipe to enable the lowest end to be immersed in the aqueous grinding fluid; the magnetic grinding machine is started, and the magnetic grinding particle media are driven by magnetic field force to move disorderly to grind and finish the inner surface of the fuel header pipe; a fuel oil header pipe is periodically adjusted to rotate in the magnetic grinding process; closing the magnetic grinding machine after the magnetic grinding time is ended; dismounting the fuel oil main pipe, dismounting the plug and pouring out the magnetic grinding particle medium; flushing a fuel oil main pipe; a fuel oil main pipe is dried; and demagnetizing the fuel manifold. The problem of polishing the inner surface of the integrated additive manufacturing fuel header pipe is solved, the quality of the inner surface can be greatly improved after polishing, and the use requirement of the fuel header pipe in a spacecraft propulsion system is met.

Description

Technical Field

[0001] The invention belongs to the technical field of surface finishing of parts, and in particular relates to a magnetic particle grinding and finishing method for the inner surface of an additively manufactured fuel main pipe. Background Art

[0002] In the aerospace field, the fuel manifold in the engine plays a vital role. The main function of the fuel manifold is to evenly distribute the fuel to the fuel spray rods, which then accurately spray the fuel into the cylinders of the engine to ensure that the mixing and combustion of the fuel and oxidizer can achieve the best thrust output.

[0003] Taking the propulsion system of a spacecraft as an example, its requirements for fuel injection are much higher than those for engines in other fields, because the spacecraft must operate stably under extreme conditions, and the propulsion system not only needs to face extreme temperature and pressure changes, but also needs to work in a microgravity environment. This requires the fuel main pipe to have extremely high stability and durability in both structure and function. It must be able to withstand extreme working conditions such as strong vibrations and drastic temperature changes, while ensuring the uniformity and accuracy of fuel distribution to ensure that the engine can operate stably and reliably.

[0004] However, the standards for the inner surface finish of the fuel manifold in other fields can no longer meet the requirements for use in spacecraft propulsion systems. Since the fuel manifold has achieved integrated additive manufacturing, traditional finishing methods are difficult to apply to the polishing of the inner surface of the fuel manifold, and the inner surface finish of the fuel manifold polished by traditional finishing methods cannot meet the requirements for use in spacecraft propulsion systems. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for magnetic particle grinding and finishing of the inner surface of an additively manufactured fuel manifold, which solves the problem of polishing the inner surface of the integrated additively manufactured fuel manifold, especially the difficult-to-polish parts at the intersection of the main channel and the fuel spray rod. After polishing, the surface quality can be greatly improved. Under the action of strong vibration and drastic temperature changes, the fatigue resistance of the fuel manifold can be effectively improved, thereby meeting its use requirements in spacecraft propulsion systems.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for magnetic particle grinding and finishing of the inner surface of a fuel manifold by additive manufacturing, comprising the following steps:

[0007] Step 1: Prepare a magnetic grinder, a robotic arm and a three-jaw chuck to process a fuel manifold fixing bracket. The magnetic grinder and the robotic arm are arranged in parallel;

[0008] Step 2: Install the three-jaw chuck as the end effector on the robot arm, and then clamp the fuel manifold bracket onto the three-jaw chuck;

[0009] Step 3: Use a mesh plug to seal all the oil outlets of the fuel main pipe to be processed, leaving only the oil inlet unblocked;

[0010] Step 4: First, load the magnetic abrasive granules into the fuel main pipe through the fuel inlet, then shake the fuel main pipe to keep the magnetic abrasive granules loose, and finally seal the fuel inlet with a mesh plug;

[0011] Step 5: Fix the fuel main pipe filled with magnetic abrasive particle media to the fuel main pipe fixing frame, and pour the aqueous grinding liquid into the water tank on the top of the magnetic grinder;

[0012] Step 6: Move the fuel main pipe to the top of the water tank of the magnetic grinder by using the mechanical arm, so that the plane where the fuel main pipe is located is inclined with respect to the horizontal plane, and at the same time, immerse the lowest end of the fuel main pipe in the aqueous grinding liquid and place it at the strongest magnetic field in the center of the water tank. At this time, the magnetic grinding particle medium will also stay at the lowest end of the fuel main pipe under the action of gravity, and the aqueous grinding liquid will enter the fuel main pipe through the mesh plug and mix with the magnetic grinding particle medium;

[0013] Step 7: Start the magnetic grinding machine to generate a rotating magnetic field, and set the magnetic grinding time so that the lowest end of the fuel main pipe is in the rotating magnetic field. Under the magnetic force of the rotating magnetic field and the combined force of inertia, buoyancy of the grinding fluid and mutual collision between the media, the magnetic grinding particle media will move disorderly inside the fuel main pipe, and then the inner surface of the fuel main pipe will be polished and finished by the disorderly moving magnetic grinding particle media;

[0014] Step 8: During the magnetic grinding process, the central axis of the three-jaw chuck is used as the rotation center line, and the mechanical arm periodically adjusts the rotation of the fuel main pipe so that the disorderly moving magnetic grinding particle medium is fully in contact with all parts inside the fuel main pipe;

[0015] Step 9: After the magnetic grinding time is over, first lift the fuel manifold upwards to make the lowest end of the fuel manifold completely out of the liquid surface of the water-based grinding liquid. When the water-based grinding liquid no longer flows out of the mesh plug on the fuel manifold, remove the fuel manifold from the fuel manifold fixing bracket;

[0016] Step 10: First, remove all mesh plugs at the fuel inlet and all fuel outlets of the fuel main pipe, and then pour out all the magnetic abrasive particle media in the fuel main pipe, and recycle the poured out magnetic abrasive particle media for reuse;

[0017] Step 11: Introduce high-pressure water from the fuel inlet of the fuel main pipe to flush the inside of the fuel main pipe and clean all the remaining grinding chips, magnetic abrasive particles and aqueous abrasive liquid;

[0018] Step 12: Place the cleaned fuel main pipe into a drying box for drying to remove residual moisture on the surface of the fuel main pipe;

[0019] Step 13: Send the dried fuel main pipe into the demagnetization machine to complete the demagnetization of the fuel main pipe.

[0020] The fuel manifold fixing frame adopts a three-arm structure, including a clamping fixing seat, a center base, an adjustable telescopic arm and a fuel manifold fixing claw; the clamping fixing seat adopts a cylindrical structure; the center base adopts a truncated cone structure, and the clamping fixing seat is coaxially fixedly connected with the small-diameter end of the truncated cone of the center base; the number of adjustable telescopic arms is three, and the three adjustable telescopic arms are evenly distributed along the circumferential direction of the large-diameter end of the truncated cone of the center base, and a fuel manifold fixing claw is provided at the outer end of each adjustable telescopic arm; the clamping fixing seat is clamped and fixedly cooperated with the three-jaw chuck; the fuel manifold fixing claw is clamped and fixedly cooperated with the fuel manifold.

[0021] Beneficial effects of the present invention:

[0022] The present invention provides a magnetic particle grinding and finishing method for the inner surface of an additively manufactured fuel manifold, which solves the problem of polishing the inner surface of an integrated additively manufactured fuel manifold, especially the difficult-to-polish parts at the intersection of the main flow channel and the fuel spray rod. After polishing, the surface quality can be greatly improved. Under the action of strong vibration and drastic temperature changes, the fatigue resistance of the fuel manifold can be effectively improved, thereby meeting the use requirements of the fuel manifold in the spacecraft propulsion system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the combination of a magnetic grinder, a mechanical arm, a three-jaw chuck and a fuel main pipe fixing frame;

[0024] Figure 2 It is a structural schematic diagram of the fuel main pipe fixing bracket;

[0025] Figure 3 It is a structural schematic diagram of the fuel main pipe;

[0026] Figure 4 This is a microscopic image of the measurement points on the inner surface of the fuel main pipe before grinding;

[0027] Figure 5 This is a microscopic image of the measurement points on the inner surface of the fuel main pipe after grinding;

[0028] In the figure, 1 is a magnetic grinder, 2 is a mechanical arm, 3 is a three-jaw chuck, 4 is a fuel main pipe fixing bracket, 5 is a fuel main pipe, 6 is a water tank, 41 is a clamping base, 42 is a center base, 43 is an adjustable telescopic support arm, and 44 is a fuel main pipe fixing claw. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] A method for magnetic particle grinding and finishing of the inner surface of a fuel main pipe by additive manufacturing includes the following steps:

[0031] Step 1: prepare a magnetic grinding machine 1, a mechanical arm 2 and a three-jaw chuck 3, and process a fuel main pipe fixing frame 4. The magnetic grinding machine 1 and the mechanical arm 2 are arranged in parallel;

[0032] Step 2: Install the three-jaw chuck 3 as the end effector on the robot arm 2, and then clamp the fuel manifold fixing bracket 4 on the three-jaw chuck 3, as shown in FIG. Figure 1 As shown;

[0033] Step 3: Use a mesh plug to Figure 3 All the oil outlets of the fuel main pipe 5 to be processed are blocked, leaving only the oil inlet unblocked; in this embodiment, the annular diameter of the fuel main pipe 5 is 600 mm, and the diameter of the circular pipe cross section of the fuel main pipe 5 is 15 mm;

[0034] Step 4: first, the magnetic abrasive granular medium is loaded into the fuel main pipe 5 through the fuel inlet, then the magnetic abrasive granular medium is kept loose by shaking the fuel main pipe 5, and finally the fuel inlet is blocked with a mesh plug; in this embodiment, the loading amount of the magnetic abrasive granular medium is 100g to 200g, and the diameter of the magnetic abrasive granular medium is 0.5mm;

[0035] Step 5: Fix the fuel main pipe 5 filled with magnetic abrasive particle media to the fuel main pipe fixing frame 4, and pour the aqueous grinding liquid into the water tank 6 on the top of the magnetic grinder 1;

[0036] Step 6: Move the fuel main pipe 5 to the top of the water tank 6 of the magnetic grinder 1 by the mechanical arm 2, so that the plane where the fuel main pipe 5 is located is inclined with respect to the horizontal plane, and at the same time, immerse the lowest end of the fuel main pipe 5 in the aqueous grinding liquid and is located at the strongest magnetic field in the center of the water tank 6. At this time, the magnetic grinding particle medium will also stay at the lowest end of the fuel main pipe 5 under the action of gravity, and the aqueous grinding liquid will enter the fuel main pipe 5 through the mesh plug and mix with the magnetic grinding particle medium;

[0037] Step 7: Start the magnetic grinding machine 1 to generate a rotating magnetic field, and set the magnetic grinding time so that the lowest end of the fuel main pipe 5 is in the rotating magnetic field. Under the magnetic force of the rotating magnetic field and the combined force of inertia, buoyancy of the grinding liquid and mutual collision force between the media, the magnetic grinding particle medium will move disorderly inside the fuel main pipe 5, and then the inner surface of the fuel main pipe 5 will be polished and finished by the disorderly moving magnetic grinding particle medium; in this embodiment, the magnetic grinding time is set to 24 hours;

[0038] Step 8: During the magnetic grinding process, the central axis of the three-jaw chuck 3 is used as the rotation center line, and the mechanical arm 2 periodically adjusts the rotation of the fuel main pipe 5 so that the disorderly moving magnetic grinding particle medium is fully in contact with all parts inside the fuel main pipe 5; in this embodiment, the fuel main pipe 5 first rotates 360° clockwise, then rotates 360° counterclockwise, and repeats this process alternately, and the rotation speed is set to 10° / s;

[0039] Step 9: After the magnetic grinding time is over, first lift the fuel manifold 5 upwards to make the lowest end of the fuel manifold 5 completely out of the liquid surface of the aqueous grinding liquid. When the aqueous grinding liquid no longer flows out of the mesh plug on the fuel manifold 5, remove the fuel manifold 5 from the fuel manifold fixing bracket 4;

[0040] Step 10: First, remove all mesh plugs at the oil inlet and all oil outlets of the fuel main pipe 5, and then pour out all the magnetic abrasive particle media in the fuel main pipe 5, and recycle the poured out magnetic abrasive particle media for reuse;

[0041] Step 11: Introduce high-pressure water from the fuel inlet of the fuel main pipe 5 to flush the interior of the fuel main pipe 5, and clean all the remaining grinding chips, magnetic grinding particle media and aqueous grinding liquid;

[0042] Step 12: Send the cleaned fuel main pipe 5 into a drying box for drying to remove residual moisture on the surface of the fuel main pipe 5;

[0043] Step 13: Send the dried fuel main pipe 5 into a demagnetizing machine to complete the demagnetization of the fuel main pipe 5.

[0044] like Figure 2As shown, the fuel manifold fixing frame 4 adopts a three-arm structure, including a clamping fixing seat 41, a center base 42, an adjustable telescopic support arm 43 and a fuel manifold fixing claw 44; the clamping fixing seat 41 adopts a cylindrical structure; the center base 42 adopts a truncated cone structure, and the clamping fixing seat 41 is coaxially fixedly connected with the small diameter end of the truncated cone of the center base 42; the number of the adjustable telescopic support arms 43 is three, and the three adjustable telescopic support arms 43 are evenly distributed along the circumferential direction of the large diameter end of the truncated cone of the center base 42, and a fuel manifold fixing claw 44 is provided at the outer end of each adjustable telescopic support arm 43; the clamping fixing seat 41 is clamped and fixedly matched with the three-jaw chuck 3; the fuel manifold fixing claw 44 is clamped and fixedly matched with the fuel manifold 5.

[0045] In order to verify the additive manufacturing magnetic particle grinding finishing method of the inner surface of the fuel manifold of the present invention, the inner flow channel surface of the fuel injection rod before and after grinding was experimentally measured. The microscopic appearance of the measurement point before grinding is as follows: Figure 4 As shown in the figure, the microscopic appearance of the measuring point after grinding is as follows Figure 5 As shown. It can be clearly seen from the microscopic morphology that the surface particles of the measuring points after grinding have been significantly removed. In addition, the roughness of the measuring points was measured before and after grinding. The roughness measurement value before grinding was Ra22μm, and the roughness measurement value after grinding was Ra0.15μm. From the roughness measurement results, the surface quality after grinding has been significantly improved.

[0046] The solutions in the embodiments are not intended to limit the protection scope of the present invention. All equivalent implementations or changes that do not deviate from the present invention are included in the protection scope of the present invention.

Claims

1. A method for magnetic particle grinding and finishing of the inner surface of a fuel manifold by additive manufacturing, characterized in that: The steps include: Step 1: Prepare a magnetic grinder, a robotic arm and a three-jaw chuck to process a fuel manifold fixing bracket. The magnetic grinder and the robotic arm are arranged in parallel; Step 2: Install the three-jaw chuck as the end effector on the robot arm, and then clamp the fuel manifold bracket onto the three-jaw chuck; Step 3: Use a mesh plug to seal all the oil outlets of the fuel main pipe to be processed, leaving only the oil inlet unblocked; Step 4: First, load the magnetic abrasive granules into the fuel main pipe through the fuel inlet, then shake the fuel main pipe to keep the magnetic abrasive granules loose, and finally seal the fuel inlet with a mesh plug; Step 5: Fix the fuel main pipe filled with magnetic abrasive particle media to the fuel main pipe fixing frame, and pour the aqueous grinding liquid into the water tank on the top of the magnetic grinder; Step 6: Move the fuel main pipe to the top of the water tank of the magnetic grinder by using the mechanical arm, so that the plane where the fuel main pipe is located is inclined with respect to the horizontal plane, and at the same time, immerse the lowest end of the fuel main pipe in the aqueous grinding liquid and place it at the strongest magnetic field in the center of the water tank. At this time, the magnetic grinding particle medium will also stay at the lowest end of the fuel main pipe under the action of gravity, and the aqueous grinding liquid will enter the fuel main pipe through the mesh plug and mix with the magnetic grinding particle medium; Step 7: Start the magnetic grinding machine to generate a rotating magnetic field, and set the magnetic grinding time so that the lowest end of the fuel main pipe is in the rotating magnetic field. Under the magnetic force of the rotating magnetic field and the combined force of inertia, buoyancy of the grinding fluid and mutual collision between the media, the magnetic grinding particle media will move disorderly inside the fuel main pipe, and then the inner surface of the fuel main pipe will be polished and finished by the disorderly moving magnetic grinding particle media; Step 8: During the magnetic grinding process, the central axis of the three-jaw chuck is used as the rotation center line, and the mechanical arm periodically adjusts the rotation of the fuel main pipe so that the disorderly moving magnetic grinding particle medium is fully in contact with all parts inside the fuel main pipe; Step 9: After the magnetic grinding time is over, first lift the fuel manifold upwards to make the lowest end of the fuel manifold completely out of the liquid surface of the water-based grinding liquid. When the water-based grinding liquid no longer flows out of the mesh plug on the fuel manifold, remove the fuel manifold from the fuel manifold fixing bracket; Step 10: First, remove all mesh plugs at the fuel inlet and all fuel outlets of the fuel main pipe, and then pour out all the magnetic abrasive particle media in the fuel main pipe, and recycle the poured out magnetic abrasive particle media for reuse; Step 11: Introduce high-pressure water from the fuel inlet of the fuel main pipe to flush the inside of the fuel main pipe and clean all the remaining grinding chips, magnetic abrasive particles and aqueous abrasive liquid; Step 12: Place the cleaned fuel main pipe into a drying box for drying to remove residual moisture on the surface of the fuel main pipe; Step 13: Send the dried fuel main pipe into the demagnetization machine to complete the demagnetization of the fuel main pipe.

2. The method for magnetic particle grinding and finishing of the inner surface of a fuel manifold by additive manufacturing according to claim 1, characterized in that: The fuel manifold fixing frame adopts a three-arm structure, including a clamping fixing seat, a center base, an adjustable telescopic arm and a fuel manifold fixing claw; the clamping fixing seat adopts a cylindrical structure; the center base adopts a truncated cone structure, and the clamping fixing seat is coaxially fixedly connected with the small-diameter end of the truncated cone of the center base; the number of adjustable telescopic arms is three, and the three adjustable telescopic arms are evenly distributed along the circumferential direction of the large-diameter end of the truncated cone of the center base, and a fuel manifold fixing claw is provided at the outer end of each adjustable telescopic arm; the clamping fixing seat is clamped and fixedly cooperated with the three-jaw chuck; the fuel manifold fixing claw is clamped and fixedly cooperated with the fuel manifold.

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