A surface treatment apparatus for an SLM engine thrust chamber

Abstract

The application discloses a surface treatment device for an SLM engine thrust chamber and relates to the technical field of additive manufacturing. The surface treatment device comprises a polishing cabin and a control system for controlling polishing treatment in the polishing cabin. The polishing cabin is internally provided with an inner cavity annular surface treatment mechanism, a single-grinding-head surface treatment mechanism, an environment control mechanism, a base component, a pneumatic adjusting mechanism, a hydraulic control mechanism and an SLM forming engine thrust chamber workpiece. The application overcomes the shortcomings of the prior art, adopts mechanical processing to improve the efficiency and consistency of production, and adopts a digital control system to realize controllable adjustment of the roughness of the inner and outer surfaces of the SLM engine thrust chamber.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to a surface treatment apparatus for the thrust chamber of an SLM engine. Background Technology

[0002] SLM (Surface Mount Metal Additive Manufacturing) is a technology that uses powder bed deposition to create a workpiece layer by layer, enabling the fabrication of complex components that are impossible with traditional machining techniques. The surface quality of additively manufactured workpieces is crucial, especially for core components in the aerospace engine field, which typically operate under high temperature and pressure conditions. The wall thickness and the surface quality of both the inner and outer walls directly affect the structural strength and heat transfer efficiency of these core components.

[0003] With the continuous advancement and development of additive manufacturing technology, surface-mount laser (SLM) additive manufacturing can basically meet the forming requirements of core components in the aerospace engine field. Given a sound design concept, additive manufacturing can simplify the development process and quickly and efficiently manufacture the required components, achieving a weight reduction of over 60% compared to traditional processes while meeting strength requirements. However, the surface quality of the formed workpiece is uneven, and the wall thickness control of irregularly shaped thin-walled cavities is uncertain. This limitation has consistently constrained the further development and application of additive manufacturing technology in this field. The active cooling thrust chamber of an SLM engine, as an indispensable part of a rocket propulsion system, has a complex structure and extremely high requirements for thickness and surface quality, especially given a wall thickness of less than 1 mm.

[0004] Currently, the main surface treatment methods used in the industry for the thrust chamber of SLM engines are manual polishing, abrasive flow, and magnetic polishing. Manual polishing has low efficiency, poor product consistency, and cannot effectively control the thickness of thin walls. Furthermore, it is difficult to treat the inner cavity surface. Abrasive flow and magnetic polishing have limited effects on improving the surface roughness of the product. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of low efficiency and poor product consistency of manual polishing in the prior art. It proposes a surface treatment device for the thrust chamber of SLM engine, which improves production efficiency and consistency by using mechanical processing, and at the same time adopts a digital control system to realize controllable and adjustable surface roughness of the inner and outer surfaces of the thrust chamber of SLM engine.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A surface treatment device for the thrust chamber of an SLM engine includes a polishing chamber and a control system for controlling the polishing process inside the polishing chamber. The polishing chamber contains an inner cavity annular surface treatment mechanism, a single grinding head surface treatment mechanism, an environmental control mechanism, a base component, a pneumatic adjustment mechanism, a hydraulic control mechanism, and an SLM forming mechanism for the engine thrust chamber workpiece. The base component includes a base located at the bottom of the polishing chamber and an annular track surrounding the upper end of the base. The lower end of the single grinding head surface treatment mechanism rotates on the annular track via a rotary connecting unit. The inner cavity annular surface treatment mechanism includes a fixed... A second telescopic arm is located at the center of the upper end of the base, and a rotating fixing tube is fixedly installed at the upper end of the second telescopic arm. The lower end of the rotating fixing tube is connected to the second telescopic arm through a rotating shaft, and the rotating shaft is driven by a motor inside the base. The upper end of the rotating fixing tube has a cross-shaped design, and each port of the cross-shaped rotating fixing tube is connected to a telescopic plate through a pneumatic adjustment mechanism. The telescopic plate has a second mounting seat for mounting the internal grinding head in each of its four directions, and a spring is installed between the telescopic plate and the second mounting seat. The SLM forming engine thrust chamber workpiece is fixed at the upper center of the polishing chamber through a hydraulic control mechanism.

[0008] Preferably, the hydraulic control mechanism includes two hydraulic turntables symmetrically arranged on both sides of the polishing chamber, and a mounting platform arranged between the two hydraulic turntables. The mounting platform is fixed to the adjacent hydraulic turntables on both sides by a load-bearing mechanism, and a rotatable fixing platform is provided on the mounting platform. The SLM-formed engine thrust chamber workpiece is fixed to the rotatable fixing platform by high-strength bolts, and the control system controls the hydraulic turntables to drive the mounting platform to rotate to a maximum angle of 180°.

[0009] Preferably, the load-bearing mechanism includes load-bearing rod A and load-bearing rod B connecting the mounting platform and the hydraulic turntable, and the load-bearing rod A, load-bearing rod B and the hydraulic turntable are fixed in a triangular structure.

[0010] Preferably, the single-grinding-head surface treatment mechanism includes a load-bearing arm mounted on a rotary connection unit, the upper end of the load-bearing arm being connected to a first telescopic arm via a universal joint, and the upper end of the first telescopic arm being mounted with an external pneumatic grinding head via a first mounting seat.

[0011] Preferably, the first telescopic arm and the second telescopic arm are respectively provided with a first clamp and a second clamp for holding the ultrasonic wall thickness measuring tool.

[0012] Preferably, the environmental control mechanism includes a spray mechanism and an air jet mechanism.

[0013] Preferably, the spraying mechanism includes several spray heads disposed at the top of the polishing chamber, the spray heads being connected to an external water tank via water pipes, and a waste liquid collection tank being disposed at the bottom of the polishing chamber.

[0014] Preferably, the air-jetting mechanism includes a high-pressure air pipe connected to the base, one end of which extends to the outside of the polishing chamber and is connected to the air compressor. Both the outer pneumatic grinding head and the inner grinding head are provided with air holes in the center, so that the air compressor can deliver high-pressure air to the outer pneumatic grinding head and the inner grinding head through the high-pressure air pipe.

[0015] Preferably, the control system includes a computer, a data processor, and a main control box. The computer transmits corresponding signals to the data processor via signal input lines, processes them, and then transmits them to the internal mechanisms of the polishing chamber via signal output lines to control various mechanisms. The main control box controls the start-up and shutdown of various mechanisms inside the polishing chamber via cables.

[0016] Preferably, the inner wall of the polishing chamber is coated with a hydrophobic coating.

[0017] Compared with the prior art, the present invention provides a surface treatment device for the thrust chamber of an SLM engine, which has the following advantages:

[0018] 1. This invention achieves efficient and consistent surface treatment of the thrust chamber surface of an SLM engine by setting up an inner cavity annular surface treatment mechanism. Four inner grinding heads and a second mounting base are evenly distributed on a telescopic disc. A spring with a small elastic coefficient is compressed between the telescopic disc and the second mounting base. In its natural state, the diameter of the telescopic disc remains at its maximum size. At the same time, the telescopic disc and the rotating fixed tube also have a pneumatic adjustment mechanism, which can reduce the size of the telescopic disc as needed. This mechanism can first move up and down quickly to match the inner cavity size, which is uniformly varying in size. When it reaches the designated position, the pneumatic adjustment mechanism makes the inner grinding head reach the required pressure between the inner cavity surface and rotate, achieving efficient and precise grinding. It retains the high precision of manual polishing and improves the processing efficiency and consistency of the inner cavity surface.

[0019] 2. This invention uses a hydraulic turntable to change the orientation of the SLM engine thrust chamber workpiece from its upright position during installation to its inverted position during surface treatment. The advantage of inverting the SLM engine thrust chamber workpiece during surface treatment is that, if dust generated during surface treatment, especially internal cavity surface treatment, falls into the flow channel and spray holes on the inner wall, it will cause secondary pollution to the thrust chamber and increase the surface treatment process. However, by inverting the workpiece, the dust will fall slowly under the action of gravity, and the droplets sprayed by the spray mechanism will accelerate the dust to fall, thus optimizing the dust problem during surface treatment and simplifying the subsequent processing of the thrust chamber.

[0020] 3. This invention optimizes the cleaning of dust inside the polishing chamber by coating the inner wall of the polishing chamber with a hydrophobic coating. When dust-coated droplets fall onto the inner wall of the polishing chamber, if the inner wall is not cleaned in time after the surface treatment, a layer of dust may adhere to it, causing inconvenience to the cleaning of the polishing chamber. After coating with a hydrophobic coating, during the surface treatment process, more dust-coated droplets will fall into the bottom waste liquid collection tank, optimizing the subsequent cleaning process of the inner wall of the polishing chamber. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the surface treatment device of the present invention;

[0022] Figure 2 This is a top view schematic diagram of the annular surface treatment mechanism of the inner cavity of the present invention.

[0023] In the diagram: 1. Computer; 2. Data processor; 3. Signal input line; 4. Signal output line; 5. Cable; 6. Main control box; 7. Water pipe; 8. Water tank; 9. High-pressure air pipe; 10. Air compressor; 11. Polishing chamber; 12. Spray head; 13. Mounting platform; 14. Rotatable fixed platform; 15. Load-bearing rod A; 16. Hydraulic turntable; 17. High-strength bolt; 18. Load-bearing rod B; 19. SLM forming engine thrust chamber workpiece; 20. External pneumatic grinding head; 21. First mounting base; 22. First clamp; 23. First telescopic arm; 24. Universal joint; 25. Load-bearing arm; 26. Rotary connection unit; 27. Internal grinding head; 28. Telescopic disc; 29. ​​Circular track; 30. Base; 31. Waste liquid collection tank; 32. Second clamp; 33. Second telescopic arm; 34. Second mounting base; 35. Rotary fixed pipe. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Example

[0026] Reference Figure 1-2The surface treatment device for the thrust chamber of an SLM engine includes a computer 1; a data processor 2; a signal input line 3; a signal output line 4; a cable 5; a main control box 6; a water pipe 7; a water tank 8; a high-pressure air pipe 9; an air compressor 10; a polishing chamber 11; a spray head 12; a mounting platform 13; a rotatable fixed platform 14; a load-bearing rod A 15; a hydraulic turntable 16; high-strength bolts 17; a load-bearing rod B 18; an SLM-formed engine thrust chamber workpiece 19; an external pneumatic grinding head 20; a first mounting base 21; a first clamp 22; a first telescopic arm 23; a universal joint 24; a load-bearing arm 25; a rotary connection unit 26; an internal grinding head 27; a telescopic disc 28; a ring track 29; a base 30; a waste liquid collection tank 31; a second clamp 32; a second telescopic arm 33; a second mounting base 34; and a rotary fixed pipe 35. It can be divided into an internal annular surface treatment system, a traditional single-head surface treatment system, an environmental control system, a base component, a control system, a pneumatic adjustment mechanism, and a hydraulic control mechanism, among which:

[0027] The hydraulic control mechanism includes a mounting platform 13, a rotatable fixed platform 14, a load-bearing rod A15, a hydraulic turntable 16, and a load-bearing rod B18. The hydraulic turntable 16 is controlled by the main control box 6, which drives the load-bearing rods A15 and B18 to rotate the mounting platform 13 to a maximum angle of 180°, allowing the SLM engine thrust chamber workpiece to be inverted for surface treatment. The load-bearing rod A15 is directly connected to the mounting platform 13, and the load-bearing rod B18 serves as an additional support for the load-bearing rod A15, enabling it to support workpieces with greater weight. The rotatable fixed platform 14 is mounted on the mounting platform 13 and can rotate horizontally. The workpiece 19 is fixed to the rotatable fixed platform 14 using high-strength bolts 17.

[0028] The annular surface treatment system includes a second clamp 32 for holding a wall thickness measuring tool, a second telescopic arm 33, an internal grinding head 27, a rotating fixed tube 35, and a telescopic disc 28. The second telescopic arm 33 is fixedly mounted on the base 30, and its telescopic direction is along the normal direction of the plane of the base 30 to ensure that the telescopic disc is parallel to the surface of the base 30. The second clamp 32 is mounted on the forearm of the second telescopic arm 33 and can be used to hold the ultrasonic wall thickness measuring tool.

[0029] A rotating fixing tube 35 is fixedly installed on the upper end of the second telescopic arm 33. The lower end of the rotating fixing tube 35 is connected to the second telescopic arm 33 through a rotating shaft, and the rotating shaft is driven by the motor inside the base 30 and controlled by the main control box 6. The upper end of the rotating fixing tube 35 is designed in a cross shape, and each port of the cross-shaped rotating fixing tube 35 is connected to a telescopic disc 28 through a pneumatic adjustment mechanism. The telescopic disc 28 is provided with a second mounting seat 34 for the inner grinding head 27 to be installed in four directions, and a spring is provided between the telescopic disc 28 and the second mounting seat 34. When not in use, the spring is in a slightly compressed state, so that the telescopic disc 28 is in its largest size state when it is not under pressure and is not pneumatically adjusted.

[0030] Furthermore, there are four inner grinding heads 27 and four second mounting bases 34, which are paired with each other and fit tightly to avoid relative sliding; the telescopic disc 28 and the second mounting base 34 are connected by a spring with a small elastic coefficient. When the inner cavity moves up and down, if the inner cavity radius decreases, the inner cavity wall exerts a pressure on the inner grinding head 27 pointing towards the center, causing the radius of the telescopic disc 28 to decrease, quickly matching the changing inner cavity size;

[0031] The rotating fixed tube 35 is directly connected to the rotating shaft at the front end of the second telescopic arm 33, which drives the telescopic disc 28, the second mounting base 34 and the inner grinding head 27 to rotate. It also has a pneumatic adjustment mechanism inside, which can finely adjust the pressure between the grinding head and the inner cavity wall to achieve the required surface treatment.

[0032] The rotating shaft and telescopic disc 28 are fixedly installed at the front end of the movable telescopic arm 23. An internal spring with a low elastic coefficient is slightly compressed, allowing the telescopic disc to be in its largest size when not under pressure and not pneumatically adjusted. The rotating shaft is driven by an internal motor in the base 30 and controlled by the main control box 6.

[0033] The rotating connection unit 26 can move in a ring along the ring track 29 on the base 30; the load-bearing arm 25 is connected to the rotating connection unit 26;

[0034] Input 3D model parameters from computer 1 and convert them into polar coordinates on the XY plane. The main control box 6 is used to control the movement of the rotary connecting unit 26, so that the first pneumatic grinding head 20 at the end of the movable telescopic arm 23 moves according to the planned trajectory. At the same time, it also controls the rotary connecting unit 26 to complete the circular feed motion, effectively avoiding dead angles.

[0035] Furthermore, the first clamp 22 can be mounted on the forearm of the movable telescopic arm 23 to hold the ultrasonic wall thickness measuring tool;

[0036] The external pneumatic grinding head 20 is mounted on the first mounting base 21 at the end of the first telescopic arm 23 and is used to perform surface treatment on the workpiece.

[0037] The environmental control system includes a water pipe 7, a water tank 8, a high-pressure air pipe 9, an air compressor 10, a polishing chamber 11, a spray head 12, and a waste liquid collection tank 31. The external pneumatic grinding head 20 and the internal grinding head 27 both have air holes in the center, which deliver high-pressure air from the air compressor 10 during operation to prevent dust generated during surface treatment from adhering to the surface of the workpiece.

[0038] The spray head 12 delivers water from the water tank 8 through the water pipe 7 and sprays it out in a wide-angle, fine spray of micro-sized droplets, which fully encapsulates the powder generated during polishing and reduces the floating time in the polishing chamber.

[0039] The inner wall of the polishing chamber 11 will be coated with a hydrophobic coating. The fine powder fully wrapped by water will greatly reduce the amount of powder adhering to the wall and accelerate the flow into the waste liquid collection tank 31, making it easier to clean the polishing chamber later.

[0040] This invention enables efficient and high-precision surface treatment of internal cavities, while also achieving surface treatment using traditional pneumatic grinding heads. It effectively ensures the accuracy of surface treatment for SLM engine thrust chambers and improves surface treatment efficiency. Before system operation, the workpiece contour coordinates are determined based on the workpiece's three-dimensional model. Two surface treatment systems are then set up to treat each location. Combined with a pneumatic adjustment mechanism and wall thickness measuring tools, this effectively ensures consistent surface treatment accuracy and quality. This invention is applicable to SLM engine thrust chambers and other thin-walled irregular curved surfaces, achieving stable surface treatment quality and uniform results.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A surface treatment device for an SLM engine thrust chamber, comprising a polishing cabin (11) and a control system that controls the polishing process inside the polishing cabin (11), characterized in that: The polishing cabin (11) is internally provided with an inner cavity annular surface treatment mechanism, a single grinding head surface treatment mechanism, an environment control mechanism, a base component, a pneumatic adjusting mechanism, a hydraulic control mechanism and an SLM forming engine thrust chamber workpiece (19); The base component comprises a base (30) arranged at the bottom end inside the polishing cabin (11) and a ring-shaped track (29) arranged around the upper end of the base, and the single grinding head surface treatment mechanism moves in a ring shape on the ring-shaped track (29) through a rotary connecting unit (26) at the lower end. The inner cavity annular surface treatment mechanism comprises a second telescopic arm (33) fixedly arranged at the central upper end of the base (30), and a rotary fixed tube (35) is fixedly installed at the upper end of the second telescopic arm (33), the rotary fixed tube (35) is connected with the second telescopic arm (33) through a rotating shaft at the lower end, the rotating shaft is driven by a motor inside the base (30), the rotary fixed tube (35) is designed in a cross shape at the upper end, each port of the cross-shaped rotary fixed tube (35) is connected with a telescopic disc (28) through a pneumatic adjusting mechanism, the telescopic disc (28) is provided with a second mounting seat (34) for mounting an inner grinding head (27) in four directions, and a spring is arranged between the telescopic disc (28) and the second mounting seat (34); The SLM forming engine thrust chamber workpiece (19) is fixedly arranged at the central upper end inside the polishing cabin (11) through the hydraulic control mechanism; The hydraulic control mechanism comprises two hydraulic turntables (16) symmetrically arranged at both sides inside the polishing cabin (11), and a mounting table (13) arranged in the middle of the two hydraulic turntables (16), the mounting table (13) is fixed between the two adjacent hydraulic turntables (16) through a load bearing mechanism, and a rotatable fixed platform (14) is arranged on the mounting table (13), the SLM forming engine thrust chamber workpiece (19) is fixed on the rotatable fixed platform (14) through a high-strength bolt (17), and a control system controls the hydraulic turntable (16) to drive the mounting table (13) to flip to a maximum angle of 180°.

2. A surface treatment device for an SLM engine thrust chamber according to claim 1, wherein, The load bearing mechanism comprises a load bearing rod A (15) and a load bearing rod B (18) connecting the mounting table (13) and the hydraulic turntable (16), and the load bearing rod A (15), the load bearing rod B (18) and the hydraulic turntable (16) are fixed in a triangular structure.

3. A surface treatment device for an SLM engine thrust chamber as defined in claim 1, wherein, The single grinding head surface treatment mechanism comprises a load bearing arm (25) mounted on the rotary connecting unit (26), a first telescopic arm (23) connected with the load bearing arm (25) through a universal joint (24) at the upper end, and an outer pneumatic grinding head (20) mounted on the first telescopic arm (23) through a first mounting seat (21) at the upper end.

4. A surface treatment device for an SLM engine thrust chamber according to claim 3, wherein, First and second clamps (22) and (32) for clamping ultrasonic wall thickness measuring tools are respectively arranged on the first and second telescopic arms (23) and (33).

5. A surface treatment device for an SLM engine thrust chamber as defined in claim 3, wherein, The environment control mechanism comprises a spraying mechanism and a gas flushing mechanism.

6. A surface treatment device for an SLM engine thrust chamber according to claim 5, wherein, The spray mechanism comprises a plurality of spray heads (12) arranged at the top end of the polishing cabin (11), the spray heads (12) are communicated with an external water tank (8) through a water pipe (7), and a waste liquid collecting groove (31) is arranged at the bottom of the polishing cabin (11).

7. A surface treatment device for an SLM engine thrust chamber as defined in claim 5, wherein The air flushing mechanism comprises a high-pressure air pipe (9) communicated with the base (30), one end of the high-pressure air pipe (9) extends to the outside of the polishing cabin (11) and is communicated with an air compressor (10), and air holes are arranged in the centers of the outer pneumatic grinding head (20) and the inner grinding head (27), so that the air compressor (10) can deliver high-pressure air to the outer pneumatic grinding head (20) and the inner grinding head (27) through the high-pressure air pipe (9).

8. A surface treatment device for an SLM engine thrust chamber as defined in claim 1, wherein, The control system comprises a computer (1), a data processor (2) and a main control box (6), the computer (1) transmits corresponding signals to the data processor (2) through a signal input line (3) for processing, and then transmits the processed signals to the polishing cabin (11) through a signal output line (4) to control each mechanism in the polishing cabin (11), and the main control box (6) controls the start and stop of each mechanism in the polishing cabin (11) through a cable (5).

9. A surface treatment device for an SLM engine thrust chamber as defined in claim 1, wherein, The inner wall of the polishing cabin (11) is coated with a hydrophobic coating.

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