Gun-following cooling device for annular air knife and cooling method using same

Abstract

The gun-following cooling device for the annular air knife comprises an additive printing gun head and a high-pressure air ring which is connected with the additive printing gun head and moves along with the additive printing gun head, and is characterized in that the high-pressure air ring comprises an outer ring and an inner ring, the inner ring is installed on the inner side of the outer ring in a matched mode, and an air compression bin is formed between the outer ring and the inner ring; an air inlet is formed in the outer side face of the outer ring and communicates with the air compression bin. The lower portions of the outer ring and the inner ring are attached and matched to form an air outlet seam which is communicated with the air compression bin. The high-pressure gas ring is connected with the additive printing gun head, the compressed gas bin and the gas outlet seam communicating with the compressed gas bin exist in the high-pressure gas ring, the Coanda effect is formed, and after gas flows to the surface of a machined workpiece, the workpiece is cooled. The invention further provides a cooling method using the device for cooling the annular air knife along with the gun, the cooling action direction, the cooling action position and the like of the high-pressure air ring are controlled and adjusted, so that more airflow of the high-pressure air ring flows to a machined part, and the utilization rate of the cooling airflow is increased.

Description

Technical Field

[0001] The present invention relates to the fields of additive manufacturing and welding processing, and more specifically to an annular air knife gun-mounted cooling device and a cooling method using the annular air knife gun-mounted cooling device. Background Art

[0002] Additive Manufacturing (AM) technology is a technology for manufacturing solid parts by gradually adding materials. Compared with the traditional material removal - machining technology, it is a "bottom-up" manufacturing method. With the continuous development of modern manufacturing, innovation and efficiency in the manufacturing process have become key issues. As a revolutionary manufacturing method, additive manufacturing technology plays an increasingly important role in this regard. Additive manufacturing allows materials to be added layer by layer to manufacture components with complex geometries, while traditional machining is carried out by consuming materials. This not only reduces material waste, but also improves production efficiency and reduces manufacturing costs.

[0003] During the additive manufacturing process, if the additive processed workpiece is not cooled in time, it will affect the material density of the workpiece and make its strength poor. Generally speaking, air cooling is a commonly used cooling method with low cost. However, in the conventional air cooling method, the distance between the air outlet and the workpiece is far, and the wind force is not large enough, so the cooling effect on the additive processed workpiece is not good. Therefore, it is very necessary to design an air cooling device with gun-mounted cooling. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides an annular air knife gun-mounted cooling device. The annular air knife gun-mounted cooling device of the present invention connects a high-pressure air ring to the additive printing gun head. There is a compressed air chamber and an air outlet slit communicating with the compressed air chamber inside the high-pressure air ring. When air is introduced into the compressed air chamber, the gas can only be ejected from the air outlet slit. Since the flow cross-section of the air outlet slit is very small, the gas is compressed and ejected at high speed, thereby forming the Coandă effect, which drives the gas inside and outside the annular high-pressure air ring to flow. When the gas flows to the surface of the processed workpiece, the workpiece is cooled and its temperature is reduced. By controlling the gas flow rate, the interlayer printing temperature can be effectively controlled, and the strength and toughness of the metal workpiece can be improved. The installation method of the high-pressure air ring can be sleeved outside the additive printing gun head or integrally installed on the side of the additive printing gun head. Through the control system, more air flow of the high-pressure air ring can be directed to the processed part, improving the utilization rate of the cooling air flow. The present invention also provides a cooling method using the annular air knife gun-mounted cooling device. By controlling and adjusting the cooling action direction, cooling action position, etc. of the high-pressure air ring, more air flow of the high-pressure air ring can be directed to the processed part, improving the utilization rate of the cooling air flow.

[0005] The specific technical solution of the present invention is as follows: The annular air knife gun-mounted cooling device includes an additive manufacturing gun head and a high-pressure air ring connected to the additive manufacturing gun head and moving with it. It is characterized in that: the high-pressure air ring includes an outer ring and an inner ring, the inner ring is fitted and installed inside the outer ring, and a compressed air chamber is formed between the outer ring and the inner ring; an air inlet is provided on the outer side surface of the outer ring, and the air inlet is communicated with the compressed air chamber; the lower parts of the outer ring and the inner ring are closely fitted to form an air outlet slit, and the air outlet slit is communicated with the compressed air chamber.

[0006] As a preference of the present invention, the inner hole of the high-pressure air ring is sleeved outside the additive manufacturing gun head, and there is a ventilation channel between the inner hole of the high-pressure air ring and the side wall of the additive manufacturing gun head.

[0007] As a preference of the present invention, the inner hole of the high-pressure air ring is connected to the outer side wall of the additive manufacturing gun head, and the ventilation channels are semi-circular holes evenly distributed in the circumferential direction.

[0008] As a preference of the present invention, the annular air knife gun-mounted cooling device further includes a clamping ring and a connecting rod. The clamping ring is sleeved around the additive manufacturing gun head at a position above the high-pressure air ring, and the high-pressure air ring is connected to the clamping ring through the connecting rod.

[0009] As a preference of the present invention, at least 3 connecting rods are evenly distributed in the circumferential direction, and the length of the connecting rod is adjustable.

[0010] As a preference of the present invention, the annular air knife gun-mounted cooling device further includes a clamping and rotating ring. The clamping and rotating ring is sleeved around the additive manufacturing gun head, and the high-pressure air ring is connected to the clamping and rotating ring and is located on the side of the additive manufacturing gun head.

[0011] As a preference of the present invention, the clamping and rotating ring includes a clamping part and a rotating part. The high-pressure air ring is connected to the rotating part and can rotate around the axis of the additive manufacturing gun head under the drive of the rotating part.

[0012] As a preference of the present invention, the rotating part and the high-pressure air ring are connected through a ventilation connecting rod, and the length of the ventilation connecting rod is adjustable.

[0013] As a preference of the present invention, the size of the gap of the air outlet slit is 0.02 mm - 0.2 mm.

[0014] As a preference of the present invention, the angle of the air outlet slit relative to the central axis of the additive manufacturing gun head in the material conveying direction is 30° inwardly converging to 45° outwardly expanding.

[0015] The cooling method of the annular air knife gun-mounted cooling device includes the following steps: Step A: The system obtains the vector velocity V of the additive printing gun head and the surface temperature T of the workpiece being processed; Step B: Project the vector velocity onto a two-dimensional Cartesian coordinate system to obtain the vector velocity V_xy in the two-dimensional Cartesian coordinate system; Step C: Take the negative value of the vector velocity in the two-dimensional Cartesian coordinate system to obtain the planar vector velocity in the opposite direction; Step D: Establish a coordinate system with the corresponding number of phases according to the number and direction of the connecting rods, and decompose the planar vector velocity in the opposite direction into the velocity values v_i of each phase of the multi-phase coordinate system; Step E: Convert the velocity values v_i of each phase to obtain the independent elongation length △l_i of the connecting rod, and convert the surface temperature T of the workpiece being processed to obtain the synchronous elongation length △l_t of the connecting rod; Step F: Calculate the elongation length △L_i = △l_i + △l_t of the connecting rod corresponding to each phase. A cooling method for the annular air knife gun-mounted cooling device includes the following steps: Step A: The system obtains the vector velocity V of the additive printing gun head; Step B: Project the vector velocity onto a two-dimensional Cartesian coordinate system to obtain the vector velocity V_xy in the two-dimensional Cartesian coordinate system; Step C: Take the negative value of the vector velocity in the two-dimensional Cartesian coordinate system to obtain the planar vector velocity in the opposite direction; Step D: The rotating part drives the high-pressure air ring to rotate to a direction biased towards the direction consistent with the planar vector velocity in the opposite direction.

[0016] A cooling method for the annular air knife gun-mounted cooling device includes the following steps: Step A: The system obtains the vector velocity V of the additive printing gun head and the surface temperature T of the workpiece being processed; Step B: Project the vector velocity onto a two-dimensional Cartesian coordinate system to obtain the vector velocity V_xy in the two-dimensional Cartesian coordinate system; Step C: Take the negative value of the vector velocity in the two-dimensional Cartesian coordinate system to obtain the planar vector velocity in the opposite direction; Step D: Convert the surface temperature T of the workpiece being processed to obtain the elongation length △L of the air supply connecting rod; Step E: The rotating part drives the high-pressure air ring to rotate to a direction biased towards the direction consistent with the planar vector velocity in the opposite direction, and the air supply connecting rod elongates by the length △L.

[0017] In summary, the present invention has the following beneficial effects: The annular air knife with-gun cooling device of the present invention connects a high-pressure air ring with an additive manufacturing gun head. There is a compressed air chamber and an air outlet slit communicating with the compressed air chamber inside the high-pressure air ring. When air is introduced into the compressed air chamber, the air can only be ejected from the air outlet slit. Since the flow cross-section of the air outlet slit is very small, the air is compressed and ejected at high speed, thus forming the Coanda effect, which drives the air inside and outside the annular high-pressure air ring to circulate. After the air flows to the surface of the workpiece to be processed, the workpiece is cooled and the temperature is reduced. By controlling the air flow rate, the interlayer printing temperature can be effectively controlled, and the strength and toughness of the metal workpiece can be improved. The installation method of the high-pressure air ring can be sleeved outside the additive manufacturing gun head, or it can be integrally installed on the side of the additive manufacturing gun head. Through the control system, more air flow of the high-pressure air ring can be made to flow to the processed part, improving the utilization rate of the cooling air flow. The present invention also provides a cooling method using the annular air knife with-gun cooling device. By controlling and adjusting the cooling action direction, cooling action position, etc. of the high-pressure air ring, more air flow of the high-pressure air ring can be made to flow to the processed part, improving the utilization rate of the cooling air flow. Brief Description of the Drawings

[0018] Figure 1 It is a perspective view of an embodiment of the annular air knife with-gun cooling device of the present invention; Figure 2 It is a perspective view of the high-pressure air ring in the attached Figure 1 of the annular air knife with-gun cooling device of the present invention; Figure 3 It is a sectional view of the attached Figure 1 of the annular air knife with-gun cooling device of the present invention; Figure 4 It is a sectional view of the attached Figure 1 of the annular air knife with-gun cooling device of the present invention; Figure 5 It is a sectional view of an embodiment of the annular air knife with-gun cooling device of the present invention; Figure 6 It is a sectional view of an embodiment of the annular air knife with-gun cooling device of the present invention; Figure 7 It is a sectional view of the attached Figure 6 of the annular air knife with-gun cooling device of the present invention with the direction of the high-pressure air ring changed; Figure 8 It is a sectional view of an embodiment of the annular air knife with-gun cooling device of the present invention; Figure 9 It is a sectional view of an embodiment of the annular air knife with-gun cooling device of the present invention; Figure 10 It is a sectional view of the attached Figure 9 of the annular air knife with-gun cooling device of the present invention with the high-pressure air ring moving downward; In the figure, 1 - additive manufacturing gun head, 2 - high-pressure air ring, 21 - outer ring, 211 - air inlet, 22 - inner ring, 23 - air compression chamber, 24 - air outlet slit, 25 - ventilation channel, 3 - clamping ring, 4 - connecting rod, 5 - clamping rotating ring, 51 - clamping part, 511 - air inlet channel, 512 - driving gear, 52 - rotating part, 521 - annular ventilation groove, 522 - ventilation hole, 523 - driven gear ring, 524 - connecting rod accommodation hole, 6 - ventilation connecting rod, 7 - telescopic device. Detailed implementation mode

[0019] The present invention will be further described below in conjunction with the drawings through specific embodiments.

[0020] As Figure 1 , Figure 2 , Figure 3 , Figure 4 , the annular air knife cooling device for the gun includes an additive manufacturing gun head 1 and a high-pressure air ring 2 connected to the additive manufacturing gun head 1 and moving with it. It is characterized in that: the high-pressure air ring 2 includes an outer ring 21 and an inner ring 22. The inner ring 22 is fitted and installed inside the outer ring 21. An air compression chamber 23 is formed between the outer ring 21 and the inner ring 22. An air inlet 211 is provided on the outer side surface of the outer ring 21, and the air inlet 211 communicates with the air compression chamber 23. The lower parts of the outer ring 21 and the inner ring 22 are closely fitted to form an air outlet slit 24, and the air outlet slit 24 communicates with the air compression chamber 23.

[0021] A large amount of heat will be generated during the processing of the additive manufacturing gun head 1. If the workpiece is not cooled in time during processing, it will affect the material density of the workpiece, making its strength poor. When air is introduced into the air compression chamber 23, the gas can only be ejected from the air outlet slit 24. Since the flow cross-section of the air outlet slit 24 is very small, the gas is compressed and ejected at a high speed, thus forming the Coanda effect, which drives the gas inside and outside the annular high-pressure air ring 2 to flow. After the gas flows to the surface of the workpiece to be processed, the workpiece is cooled and the temperature is reduced. By controlling the gas flow rate, the interlayer printing temperature can be effectively controlled, and the interlayer temperature can be accurately controlled, which can reduce the influence of thermal stress, improve the growth and orientation of grains, and help optimize the mechanical properties and microstructure of the workpiece; controlling the interlayer temperature helps to refine grains and improve the strength and toughness of metal workpieces; by optimizing the temperature gradient, the formation of fine grains can be promoted, which helps to improve the material properties and reduce the residual stress of the component.

[0022] As Figure 1 , Figure 2 , Figure 3 , Figure 4 , the inner hole of the high-pressure air ring 2 is sleeved outside the additive manufacturing gun head 1, and there is a ventilation channel 25 between the inner hole of the high-pressure air ring 2 and the side wall of the additive manufacturing gun head 1.

[0023] The inner hole of the high-pressure air ring 2 is sleeved outside the additive manufacturing gun head 1, enabling it to move along with the additive manufacturing gun head 1. During the processing of the additive manufacturing gun head 1, it can immediately cool the workpiece being processed, and the cooling range expands outward with the additive manufacturing gun head 1 as the center, always acting on the processing area. There is a ventilation channel 25 between the inner hole of the high-pressure air ring 2 and the side wall of the additive manufacturing gun head 1, which can increase the air flow rate and improve the cooling effect.

[0024] As Figure 2 、 Figure 4 , the inner hole of the high-pressure air ring 2 is connected to the outer side wall of the additive manufacturing gun head 1, and the ventilation channels 25 are semi-circular holes evenly distributed in the circumferential direction.

[0025] When the through-flow rate of the ventilation channel 25 is too large, the air flow inside the inner circle of the high-pressure air ring 2 has a greater impact on the surrounding area of the additive manufacturing gun head 1. Especially when the additive manufacturing gun head 1 is used in conjunction with protective gas, the air flow inside the inner circle of the high-pressure air ring 2 will affect the stability of the protective gas. As an embodiment, the ventilation channels 25 being semi-circular holes evenly distributed in the circumferential direction can reduce the through-flow rate, make the air flow more stable, and enable the inner circle of the high-pressure air ring 2 to be directly connected to the additive manufacturing gun head 1, with a simple and compact structure, reduced volume and weight, and being more suitable for use with the gun.

[0026] As Figure 1 、 Figure 3 、 Figure 5 , the gun-mounted air knife cooling device further includes a clamping ring 3 and a connecting rod 4. The clamping ring 3 is sleeved around the additive manufacturing gun head 1 at a position above the high-pressure air ring 2, and the high-pressure air ring 2 is connected to the clamping ring 3 through the connecting rod 4.

[0027] As an embodiment, as Figure 5 , connecting the high-pressure air ring 2 and the additive manufacturing gun head 1 through the clamping ring 3 and the connecting rod 4 can completely separate the inner hole of the high-pressure air ring 2 from the outer side wall of the additive manufacturing gun head 1, thereby increasing the through-flow area of the inner hole of the high-pressure air ring 2, increasing the air flow rate, and improving the cooling effect.

[0028] As Figure 6 , there are at least 3 connecting rods 4 evenly distributed in the circumferential direction, and the length of the connecting rod 4 is adjustable.

[0029] As an embodiment, as Figure 7 , the adjustable length of the connecting rod 4 enables the central axis of the high-pressure air ring 2 to deflect relative to the central axis of the additive manufacturing gun head 1 to change the air flow direction of the high-pressure air ring 2. It can be controlled by the control system to deflect the high-pressure air ring 2 backward in the moving direction of the additive manufacturing gun head 1, so that more air flow blows towards the processed part to improve the cooling effect. The length of the connecting rod 4 can be driven by a lead screw motor, a linear motor, etc.

[0030] As Figure 8 、Figure 9 , Figure 10 , the annular air knife with gun cooling device further includes a clamping and rotating ring 5, the clamping and rotating ring 5 is sleeved on the periphery of the additive manufacturing gun head 1, and the high-pressure air ring 2 is connected to the clamping and rotating ring 5 and is located on the side of the additive manufacturing gun head 1.

[0031] As an embodiment, the high-pressure air ring 2 is installed on the side of the additive manufacturing gun head 1 through the clamping and rotating ring 5, which can offset the air flow cooling area relative to the processing area, so that more air flow blows towards the processed part, thereby improving the cooling effect and reducing the influence of the air flow on the processing part.

[0032] Such as Figure 8 , the clamping and rotating ring 5 includes a clamping part 51 and a rotating part 52, the high-pressure air ring 2 is connected to the rotating part 52, and can rotate around the axis of the additive manufacturing gun head 1 as the central axis under the drive of the rotating part 52.

[0033] The high-pressure air ring 2 can rotate around the axis of the additive manufacturing gun head 1 as the central axis under the drive of the rotating part 52, and can be controlled by the control system to deflect backward in the moving direction of the high-pressure air ring 2 towards the additive manufacturing gun head 1, so that more air flow blows towards the processed part, thereby improving the cooling effect.

[0034] As an embodiment, such as Figure 8 , an annular ventilation groove 521 is formed on the upper surface of the rotating part 52, a ventilation hole 522 communicating with the bottom of the annular ventilation groove 521 is formed on the lower surface, an air inlet channel 511 is formed on the clamping part 51, the lower end of the air inlet channel 511 is opposite to the position of the annular ventilation groove 521, the outer end of the ventilation hole 522 is connected to the air inlet 211 relatively, and sealing rings are installed on the inner and outer sides of the annular ventilation groove 521 and the air inlet channel 511; a driven gear ring 523 is provided on the upper part of the rotating part 52, and a driving gear 512 matching with the driven gear ring 523 is provided on the side surface of the clamping part 51, and the driving gear 512 is driven by a motor.

[0035] Such as Figure 9 , Figure 10 , the rotating part 52 and the high-pressure air ring 2 are connected by a ventilation connecting rod 6, and the length of the ventilation connecting rod 6 is adjustable.

[0036] The high-pressure air ring 2 intakes air through the ventilation connecting rod 6, and can adjust the distance from the cooling area, so as to adjust the cooling effect.

[0037] As an embodiment, such as Figure 9 , Figure 10, a connecting rod receiving hole 524 is provided at the bottom of the rotating part 52. The ventilation connecting rod 6 is fitted and installed in the connecting rod receiving hole 524 and is sealed at the bottom of the connecting rod receiving hole 524 by a seal, so that the ventilation connecting rod 6 will not leak air during the axial movement in the connecting rod receiving hole 524; A telescopic device 7 can be installed between the high-pressure air ring 2 and the rotating part 52 to change the distance between the high-pressure air ring 2 and the rotating part 52. The telescopic device 7 is preferably a lead screw motor, a linear motor, etc.

[0038] The size of the air outlet gap 24 is 0.02 mm - 0.2 mm.

[0039] The size of the air outlet gap 24 is preferably close to 0.05 mm, which will make the Coanda effect of the high-pressure air ring 2 more obvious.

[0040] The air outlet gap 24 has an angle of inward convergence of 30° to outward expansion of 45° along the material conveying direction with respect to the central axis of the additive manufacturing gun head 1.

[0041] When the angle of the air outlet gap 24 with respect to the central axis of the additive manufacturing gun head 1 expands outward, the air outlet inside the annular high-pressure air ring 2 is relatively dispersed, reducing the influence on the processing part of the additive manufacturing gun head 1, and can expand the cooling range of action, so that more airflows blow to the processed part to improve the cooling effect, which is more suitable for cooling during additive manufacturing; When the angle of the air outlet gap 24 with respect to the central axis of the additive manufacturing gun head 1 converges inward, the air outlet inside the annular high-pressure air ring 2 is more concentrated, the wind force is greater and more concentrated, which is more suitable for cooling after the additive manufacturing is completed; In order to improve the processing and cooling efficiency, the gun-cooling method is usually adopted, and the angle of the air outlet gap 24 with respect to the central axis of the additive manufacturing gun head 1 in the material conveying direction is controlled within 5° to 45° of outward expansion.

[0042] The cooling method of the annular air knife gun-cooling device is used for examples such as Figure 6 , Figure 7 , and includes the following steps: Step A: The system obtains the vector velocity V of the additive manufacturing gun head 1 and the surface temperature T of the workpiece to be processed; Step B: Project the vector velocity onto a plane rectangular coordinate system to obtain the vector velocity V_xy on the plane rectangular coordinate system; Step C: Take the negative value of the vector velocity on the plane rectangular coordinate system to obtain the plane vector velocity in the opposite direction; Step D: Establish a coordinate system with the corresponding number of phases according to the number and direction of the connecting rods 4, and decompose the plane vector velocity in the opposite direction into the velocity values v_i of each phase of the multi-phase coordinate system; Step E: Convert the velocity values v_i of each phase to obtain the independent elongation length △l_i of the connecting rod 4, and convert the surface temperature T of the workpiece to be processed to obtain the synchronous elongation length △l_t of the connecting rod 4; Step F: Calculate the elongation length ΔL_i of the connecting rod 4 corresponding to each phase, where ΔL_i = Δl_i + Δl_t.

[0043] As an embodiment, the vector velocity V of the additive manufacturing gun head 1 can be obtained by means such as gyroscopes and vision algorithms, and the surface temperature T of the workpiece being processed can be obtained by a thermal imager; for convenient control, usually three connecting rods 4 are selected, and the phase coordinate system in step D is a three-phase coordinate system. Transformation methods such as inverse Clark transformation can be used to decompose the planar vector velocity into the velocity values in the three-phase coordinate system.

[0044] The cooling method of the annular air knife gun-mounted cooling device is used for, for example, Figure 8 the embodiments as follows, and includes the following steps: Step A: The system obtains the vector velocity V of the additive manufacturing gun head 1. Step B: Project the vector velocity onto the planar rectangular coordinate system to obtain the vector velocity V_xy on the planar rectangular coordinate system. Step C: Take the negative value of the vector velocity on the planar rectangular coordinate system to obtain the planar vector velocity in the opposite direction. Step D: The rotating part 52 drives the high-pressure air ring 2 to rotate to a direction biased towards the direction consistent with the planar vector velocity in the opposite direction.

[0045] As an embodiment, the vector velocity V of the additive manufacturing gun head 1 can be obtained by means such as gyroscopes and vision algorithms, and the surface temperature T of the workpiece being processed can be obtained by a thermal imager; the rotation of the rotating part 52 can be driven by a stepper motor or a servo motor, thus facilitating the control of the rotation angle.

[0046] The cooling method of the annular air knife gun-mounted cooling device is used for, for example, Figure 9 , Figure 10 the embodiments as follows, and includes the following steps: Step A: The system obtains the vector velocity V of the additive manufacturing gun head 1 and the surface temperature T of the workpiece being processed. Step B: Project the vector velocity onto the planar rectangular coordinate system to obtain the vector velocity V_xy on the planar rectangular coordinate system. Step C: Take the negative value of the vector velocity on the planar rectangular coordinate system to obtain the planar vector velocity in the opposite direction. Step D: Convert the surface temperature T of the workpiece being processed to obtain the elongation length ΔL of the air supply connecting rod 6. Step E: The rotating part 52 drives the high-pressure air ring 2 to rotate to a direction biased towards the direction consistent with the planar vector velocity in the opposite direction, and the air supply connecting rod 6 elongates by the length ΔL.

[0047] As an embodiment, the vector velocity V of the additive printing gun head 1 can be obtained by means of gyroscopes, vision algorithms, etc., and the surface temperature T of the workpiece to be processed can be obtained by a thermal imager; the rotation of the rotating part 52 can be driven by a stepper motor or a servo motor, so that the rotation angle can be easily controlled; the elongation length of the ventilation connecting rod 6 can be driven by a lead screw stepper motor, so that the telescopic length can be easily controlled.

[0048] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope of the present invention, and the technical content claimed by the present invention has been fully recorded in the claims.

Claims

1. Ring-shaped air knife gun-mounted cooling device, comprising an additive manufacturing gun head (1), and a high-pressure air ring (2) connected to the additive manufacturing gun head (1) and moving with it. Characterized in that: The high-pressure air ring (2) includes an outer ring (21) and an inner ring (22), the inner ring (22) is fitted and installed inside the outer ring (21), and a compressed air chamber (23) is formed between the outer ring (21) and the inner ring (22); an air inlet (211) is provided on the outer side surface of the outer ring (21), and the air inlet (211) communicates with the compressed air chamber (23); the lower parts of the outer ring (21) and the inner ring (22) are closely fitted to form an air outlet slit (24), and the air outlet slit (24) communicates with the compressed air chamber (23).

2. The ring-shaped air knife gun-mounted cooling device according to claim 1, Characterized in that: The inner hole of the high-pressure air ring (2) is sleeved outside the additive manufacturing gun head (1), and there is a ventilation channel (25) between the inner hole of the high-pressure air ring (2) and the side wall of the additive manufacturing gun head (1).

3. The ring-shaped air knife gun-mounted cooling device according to claim 2, Characterized in that: The inner hole of the high-pressure air ring (2) is connected to the outer side wall of the additive manufacturing gun head (1), and the ventilation channels (25) are semi-circular holes evenly distributed in the circumferential direction.

4. The ring-shaped air knife gun-mounted cooling device according to claim 2, Characterized in that: The ring-shaped air knife gun-mounted cooling device further includes a clamping ring (3) and a connecting rod (4), the clamping ring (3) is sleeved around the additive manufacturing gun head (1) at a position above the high-pressure air ring (2), and the high-pressure air ring (2) is connected to the clamping ring (3) through the connecting rod (4).

5. The ring-shaped air knife gun-mounted cooling device according to claim 4, Characterized in that: At least 3 connecting rods (4) are evenly distributed in the circumferential direction, and the length of the connecting rod (4) is adjustable.

6. The ring-shaped air knife gun-mounted cooling device according to claim 1, Characterized in that: The ring-shaped air knife gun-mounted cooling device further includes a clamping and rotating ring (5), the clamping and rotating ring (5) is sleeved around the additive manufacturing gun head (1), and the high-pressure air ring (2) is connected to the clamping and rotating ring (5) and is located on the side of the additive manufacturing gun head (1).

7. The ring-shaped air knife gun-mounted cooling device according to claim 6, Characterized in that: The clamping and rotating ring (5) includes a clamping part (51) and a rotating part (52), the high-pressure air ring (2) is connected to the rotating part (52), and can rotate around the axis of the additive manufacturing gun head (1) as the central axis under the drive of the rotating part (52).

8. The ring-shaped air knife gun-mounted cooling device according to claim 7, Characterized in that: The rotating part (52) and the high-pressure air ring (2) are connected through a ventilation connecting rod (6), and the length of the ventilation connecting rod (6) is adjustable.

9. The ring-shaped air knife gun-mounted cooling device according to any one of claims 1-8, Characterized in that: The size of the gap of the air outlet slit (24) is 0.02 mm - 0.2 mm.

10. The annular air knife gun-mounted cooling device according to any one of claims 2-5, characterized in that: the included angle of the air outlet slit (24) relative to the central axis of the additive manufacturing gun head (1) in the material conveying direction is 30° inwardly converging to 45° outwardly expanding.

11. A cooling method for the annular air knife gun-mounted cooling device, characterized in that, for the annular air knife gun-mounted cooling device according to claim 5, comprising the following steps: Step A: The system obtains the vector velocity V of the additive manufacturing gun head (1) and the surface temperature T of the workpiece to be processed; Step B: Project the vector velocity onto a plane rectangular coordinate system to obtain the vector velocity V_xy on the plane rectangular coordinate system; Step C: Take the negative value of the vector velocity on the plane rectangular coordinate system to obtain a plane vector velocity in the opposite direction; Step D: Establish a coordinate system with corresponding phases according to the number and direction of the connecting rods (4), and decompose the plane vector velocity in the opposite direction into the velocity values v_i of each phase of the multi-phase coordinate system; Step E: Convert each phase velocity value v_i to obtain the independent elongation length △l_i of the connecting rod (4), and convert the surface temperature T of the workpiece to be processed to obtain the synchronous elongation length △l_t of the connecting rod (4); Step F: Calculate the elongation length △L_i = △l_i + △l_t of the connecting rod (4) corresponding to each phase.

12. A cooling method for the annular air knife gun-mounted cooling device, characterized in that, for the annular air knife gun-mounted cooling device according to claim 7, comprising the following steps: Step A: The system obtains the vector velocity V of the additive manufacturing gun head (1); Step B: Project the vector velocity onto a plane rectangular coordinate system to obtain the vector velocity V_xy on the plane rectangular coordinate system; Step C: Take the negative value of the vector velocity on the plane rectangular coordinate system to obtain a plane vector velocity in the opposite direction; Step D: The rotating part (52) drives the high-pressure air ring (2) to rotate to a direction biased to be consistent with the plane vector velocity in the opposite direction.

13. A cooling method for the annular air knife gun-mounted cooling device, characterized in that, for the annular air knife gun-mounted cooling device according to claim 8, comprising the following steps: Step A: The system obtains the vector velocity V of the additive manufacturing gun head (1) and the surface temperature T of the workpiece to be processed; Step B: Project the vector velocity onto a plane rectangular coordinate system to obtain the vector velocity V_xy on the plane rectangular coordinate system; Step C: Take the negative value of the vector velocity on the plane rectangular coordinate system to obtain a plane vector velocity in the opposite direction; Step D: Convert the surface temperature T of the workpiece to be processed to obtain the elongation length △L of the air supply connecting rod (6); Step E: The rotating part (52) drives the high-pressure air ring (2) to rotate to a direction biased to be consistent with the plane vector velocity in the opposite direction, and the air supply connecting rod (6) elongates by the length △L.

Images