Swinging continuous feeding friction stir additive manufacturing device and additive manufacturing method

Abstract

The present application first proposes a swing-type continuous feeding stir friction additive manufacturing device, which includes a stirring mechanism, a pressing mechanism, a feeding mechanism and a control system; the stirring mechanism includes a stirring head with a feeding hole, the lower end of the stirring head is a shaft shoulder, the pressing mechanism includes two feeding barrels and a swing mechanism that drives the feeding barrel to swing and reach the feeding position, and a pressing piston cylinder is fixedly installed on the top of the feeding barrel. The feeding mechanism is used to feed the rod into the feeding barrel, and the control system is used to control the swing of the swing mechanism. The present application also discloses an additive manufacturing method using the above-mentioned stir friction additive manufacturing device. The present application uses the alternating use of two feeding barrels to reduce the time it takes for the rod to enter the feeding hole. Since the switching time of the two feeding barrels is short, the additive system does not need to pause and can work continuously. The fluidity of the plasticized rod and the flattening effect of the shaft shoulder can be used to compensate for the feeding interruption caused by the short interval between the two rods.

Description

Technical Field

[0001] The invention relates to a swing-type continuous feeding friction stir additive manufacturing device and an additive manufacturing method. Background Art

[0002] In existing friction stir additive deposition processes, materials used include rods, wires, and powders. Wires facilitate continuous feeding, but due to their poor rigidity, they are prone to squeezing out of the stirrer's shoulder. Powders offer the advantage of convenient composition configuration, but they have high particle size requirements, resulting in high raw material costs and a tendency for the discharge port to clog during welding. Rods offer the advantages of low raw material costs and high performance, but they suffer from poor feeding continuity.

[0003] At present, when rods are used as additive raw materials, the rods are generally pressed down by a piston cylinder, and the piston rod of the piston cylinder is used to push the rod downward to generate a forging force. When another rod needs to be loaded, the piston rod needs to be lifted upward to feed the next rod into the center hole of the stirring head. When the piston rod is lifted upward, the previous rod will lose the pressure of the piston rod, resulting in a temporary disappearance of the forging force until the next rod is pressed against the previous rod. When the forging force disappears temporarily, the plasticization and deposition of the rod will be interrupted, thereby affecting the internal quality and external geometry of the additively manufactured parts.

[0004] In view of the above, there are still challenges in the friction stir additive deposition process using rods, such as improving the continuity of rod feeding and thereby improving the quality of deposited materials. Summary of the Invention

[0005] In order to solve the problem of continuous rod feeding and improve the quality of deposited materials, the present application first proposes a swing-type continuous feeding friction stir additive manufacturing device, which includes a stirring mechanism, a material pressing mechanism, a material feeding mechanism and a control system; the stirring mechanism includes a stirring head and a material discharge hole formed in the stirring head, the material discharge hole extending in a vertical direction, the lower end of the stirring head forming a shaft shoulder, and a stirring needle is provided on the lower end surface of the shaft shoulder; a mounting portion is provided on the stirring head, which is used to mount the stirring head to the rotating mechanism of the additive manufacturing equipment; the cross-section of the material discharge hole and the rod are both square, and the side length of the cross-section of the rod is 0.2-1 mm shorter than the side length of the cross-section of the material discharge hole;

[0006] The material pressing mechanism includes two feeding barrels and a swinging mechanism for driving the two feeding barrels to swing, the two feeding barrels are arranged to be relatively inclined, and the two feeding barrels are both located at the top of the stirring head. Driven by the swinging mechanism, the two feeding barrels can reach the feeding position in turn, and when any feeding barrel is at the feeding position, the inner cavity of the feeding barrel is coaxially arranged with the discharge hole and is connected to each other; corresponding to each feeding barrel, a pressing piston cylinder is fixedly installed on the top of the feeding barrel, and the piston rod of the pressing piston cylinder can extend into the corresponding feeding barrel to press the rod material in the feeding barrel into the discharge hole; the two feeding barrels are respectively the first feeding barrel and the second feeding barrel, and the two pressing piston cylinders are respectively the first piston cylinder and the second piston cylinder, the first piston cylinder is installed on the top of the first feeding barrel, and the second piston cylinder is installed on the top of the second feeding barrel;

[0007] The feeding mechanism is used to feed the bar material into the feeding cylinder, and the control system is used to control the swing of the swing mechanism.

[0008] In this application, two feeding barrels are used alternately to reduce the time it takes for the next rod to enter the discharge hole. When the top surface of the rod in the feeding barrel in the working state drops to be flush with the upper edge of the discharge hole, there is no need to retract the piston rod of the pressing piston cylinder. The positions of the two feeding barrels can be switched, so that the other feeding barrel reaches the feeding position and delivers the next rod to the discharge hole. The switching time between the two feeder barrels determines the interval between two adjacent bars entering the feed hole. With automatic control, switching between the two feeder barrels can typically be completed within 0.01-0.03 seconds. However, in the prior art, the piston rod of the press cylinder must be fully retracted before the next bar can be fed into the system. This results in a long interval between adjacent bars. The length of this interval depends primarily on the length of the bar. The longer the bar, the longer it takes for the piston rod to fully retract, and the longer the additive system pauses. However, with this application, the switching time between the two feeder barrels is shortened, allowing the additive system to operate continuously without pausing. The fluidity of the plasticized bar and the flattening effect of the shoulder compensate for the feeding interruption caused by the brief interval between the two bars.

[0009] In addition, since the present application provides two feeding barrels and corresponding pressing piston cylinders, even if one of the pressing piston cylinders is temporarily suspended due to a malfunction, the other pressing piston cylinder can be used to complete production using the existing production process, thereby avoiding the product being scrapped due to inability to complete and causing waste. Since the feeding barrel has no moving parts and is only a cylindrical component, the problem of its failure is generally not considered.

[0010] Furthermore, to facilitate installation of the oscillating mechanism, a support plate is rotatably mounted on the mixing head, to which the oscillating mechanism is fixedly mounted. The support plate facilitates determining the relative position of the oscillating mechanism and the mixing head, improving operational convenience and eliminating the need to adjust the position between the feed barrel and the mixing head before each operation. The support plate is intended to be secured to the fixing mechanism of the additive manufacturing equipment.

[0011] Specifically, the swing mechanism includes a swing cylinder and a swing frame. The swing cylinder is fixedly mounted on the support plate. One end of the swing frame is fixedly connected to the swing cylinder's swing table, and the other end of the swing frame is fixedly connected to the two feed barrels. The swing cylinder can conveniently control the swing of the two feed barrels, and the swing frame mainly serves as a transition, so that the swing cylinder's swing table can be easily connected to the two feed barrels.

[0012] Furthermore, in order to avoid shaking of the feeding barrel and the pressing piston cylinder and to ensure the stability of the structure, a support member is fixedly installed on the support plate, and a slide groove is provided on the side of the support member facing the feeding barrel. A slide rod is slidably installed in the slide groove, and the end of the slide rod away from the support member is fixed on the top of the feeding barrel, and the swing frame is fixed on the bottom of the feeding barrel.

[0013] Specifically, the feeding mechanism includes two feeding boxes, each corresponding to a feeding tube. A feed port is provided on the side of the feeding tube facing away from the swing mechanism, and a discharge port is provided on one side of the feeding box. The feeding box is fixedly mounted on the corresponding feeding tube, with the discharge port connected to the feed port. The feeding box extends in a direction perpendicular to the feed port. A pushing mechanism is provided on the feeding box, which is used to push the bar material in the feeding box into the feeding tube. Since each feeding tube is equipped with a feeding box, production continuity is guaranteed. Even if one feeding box fails, production can be completed in the existing manner by relying solely on the other feeding box, avoiding the scrapping of unfinished products.

[0014] Specifically, the pushing mechanism includes a push plate and a pushing piston cylinder installed on the side of the feed box away from the discharge port. The piston rod of the pushing piston cylinder is fixedly connected to the push plate, and the space between the push plate and the discharge port becomes a accommodating chamber for accommodating the bar stock. The accommodating chamber can only accommodate one row of bar stock. Under the push of the pushing piston cylinder, the bar stock in the accommodating chamber can enter the corresponding feed tube in sequence. This design is simple and practical, with low manufacturing costs. Since the accommodating chamber can only accommodate one row of bar stock, the bar stock can be smoothly moved into the feed tube. When using multiple rows of bar stock, a special adjustment mechanism needs to be set at the discharge port to avoid mutual squeezing between the bar stock in the same row, which prevents them from entering the feed tube and affecting the normal operation.

[0015] Specifically, in order to improve the flexibility of the feeding barrel during rotation, the stirring head is cylindrical, the feeding hole extends along the axial direction of the stirring head, and the top surface of the stirring head is hemispherical. A number of universal ball heads are installed on the lower end surface of the feeding barrel. The number of universal ball heads are arranged at intervals around the lower end surface of the feeding barrel, and the feeding barrel is supported on the stirring head via the universal ball heads.

[0016] Specifically, the angle between the two feeding barrels is 30-60 degrees. If the angle is too small, the inner cavities of the two feeding barrels are easily connected from the bottom, causing the bars in the two feeding barrels to interfere with each other. If the angle is too large, the working efficiency will be reduced.

[0017] Furthermore, in order to improve the flexibility and efficiency of the operation, a first induction magnetic ring is installed on the first piston of the first piston cylinder, and a second induction magnetic ring is installed on the second piston of the second piston cylinder; the control system includes a central processing unit, a first magnetic induction switch and a second magnetic induction switch connected to the central processing unit, and a swing mechanism control unit, wherein:

[0018] a central processing unit, configured to receive information from the first magnetic induction switch and the second magnetic induction switch, and issue control instructions based on the information to control the operation of the swing mechanism;

[0019] a first magnetic induction switch, for sensing the first induction magnetic ring to detect the stroke of the first piston and send information to the central processing unit;

[0020] a second magnetic induction switch, for sensing the second induction magnetic ring to detect the stroke of the second piston and send information to the central processing unit;

[0021] The swing mechanism control unit is used to control the operation of the swing mechanism so that the swing mechanism drives the two feeding cylinders to swing.

[0022] Secondly, the present application also discloses an additive manufacturing method, which is performed using any of the above-mentioned swing-type continuous feed friction stir additive manufacturing devices, and the additive manufacturing method comprises the following steps:

[0023] (1) Place the shoulder on the surface of the area to be added to the substrate, so that the first feeding cylinder reaches the feeding position, and then feed the rod into the first feeding cylinder through the feeding mechanism. The piston rod of the first piston cylinder pushes the rod in the first feeding cylinder downward until the rod is pressed against the surface of the area to be added, and the first piston cylinder is paused;

[0024] (2) Start the stirring head to preheat the shaft shoulder and the upper surface of the substrate by friction for 10-25 seconds, and the rod rotates synchronously under the drive of the stirring head;

[0025] (3) Start the first piston cylinder again, and the piston rod of the first piston cylinder pushes the rod to move downward, so that a forging force is generated between the rod and the area to be added on the substrate, and at the same time, the stirring head is retracted upward by 0.2-2.0 mm, and the stirring head is moved along the set path. The rod is thermally plasticized under the action of friction and flows out from the discharge hole. The stirring head is kept rotating and drives the rod to rotate synchronously. The rod is thermally plasticized and deposited on the substrate, and an additive forming surface is formed under the flattening action of the shoulder, so that a single layer of material is stacked in the area to be added, forming an additive manufacturing layer;

[0026] (4) When the top surface of the bar material in the first feeding cylinder drops to be flush with the upper edge of the discharge hole, the first piston cylinder is paused, the swing mechanism is started, and the second feeding cylinder reaches the feeding position, and then the second piston cylinder is started, and the piston rod of the second piston cylinder pushes the bar material in the second feeding cylinder into the discharge hole and continues to push downward; the piston rod of the first piston cylinder is retracted, and the feeding mechanism feeds the bar material into the first feeding cylinder; or

[0027] When the top surface of the bar material in the first feeding barrel drops to be flush with the upper edge of the discharge hole, the piston rod of the first piston cylinder is lifted upward, and the swing mechanism is started at the same time, so that the second feeding barrel reaches the feeding position, and then the second piston cylinder is started, and the piston rod of the second piston cylinder pushes the bar material in the second feeding barrel into the discharge hole and continues to push downward; when the piston rod of the first piston cylinder retracts, it pauses and stands by, and the feeding mechanism feeds the bar material into the first feeding barrel;

[0028] (5) When the top surface of the bar material in the second feeding cylinder drops to be flush with the upper edge of the discharge hole, the second piston cylinder is paused, the swing mechanism is started, and the first feeding cylinder reaches the feeding position, and then the first piston cylinder is started, and the piston rod of the first piston cylinder pushes the bar material in the first feeding cylinder into the discharge hole and continues to push downward; the piston rod of the second piston cylinder is retracted, and the feeding mechanism feeds the bar material into the second feeding cylinder; or

[0029] When the top surface of the bar material in the second feeding barrel drops to be flush with the upper edge of the discharge hole, the piston rod of the second piston cylinder is lifted upward, and the swing mechanism is started at the same time, so that the first feeding barrel reaches the feeding position, and then the first piston cylinder is started, and the piston rod of the first piston cylinder pushes the bar material in the first feeding barrel into the discharge hole and continues to push downward; when the piston rod of the second piston cylinder retracts, it pauses and stands by, and the feeding mechanism feeds the bar material into the second feeding barrel;

[0030] (6) Repeat steps (4) and (5) to repeatedly stack a single layer of material in the area to be added, thereby achieving continuous manufacturing of the additive process until the required additive height is reached.

[0031] In this application, the two feeding barrels are used alternately. When the top surface of the bar in the feeding barrel in the working state drops to be flush with the upper edge of the discharge hole, the positions of the two feeding barrels can be switched without retracting the piston rod of the pressing piston cylinder, so that the other feeding barrel reaches the feeding position and delivers the next bar into the discharge hole, thereby reducing the interval time between two adjacent bar materials entering the discharge hole. The switching time of the two feeding barrels determines the interval time between two adjacent bar materials. When automatic control is adopted, the switching of the two feeding barrels can be completed within 0.01-0.03 seconds under normal circumstances. When the existing technology is used, the piston rod of the pressing piston cylinder needs to be retracted. Since the piston cylinder is designed according to the consumption rate of the rod, the movement speed of its piston rod is slow. Depending on the different lengths of the rods, it usually takes 1-5 minutes for the piston rod to complete the retraction before the next rod can be fed into the system, resulting in a long interval between the two adjacent rods. The length of the interval time mainly depends on the length of the rod. The longer the rod, the longer the time it takes for the piston rod to complete the retraction, and the longer the additive system is paused. After adopting the present application, since the switching time of the two feeding barrels is short, the additive system does not need to be paused and can work continuously. The fluidity of the plasticized rod and the flattening effect of the shoulder can make up for the feeding interruption caused by the short interval between the two rods.

[0032] In addition, since the present application provides two feeding barrels and corresponding pressing piston cylinders, even if one of the pressing piston cylinders fails, the other pressing piston cylinder can be used to complete production using the existing production process, avoiding the product being scrapped due to inability to complete, resulting in waste. Since the feeding barrel has no moving parts and is only a cylindrical component, the problem of its failure is generally not considered. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural diagram of an embodiment of the present invention.

[0034] Figure 2 yes Figure 1 Right view of .

[0035] Figure 3 yes Figure 2 View with the swing mechanism removed. DETAILED DESCRIPTION

[0036] The following first describes the swing-type continuous feed friction stir additive manufacturing device. Figure 1-Figure 3The swing-type continuous-feed friction stir additive manufacturing device includes a stirring mechanism 100, a pressing mechanism 200, a feeding mechanism 500, and a control system. The stirring mechanism 100 includes a stirring head 11 and a feed hole 17 formed in the stirring head. The feed hole 17 extends in the vertical direction. The lower end of the stirring head 11 is formed into a shaft shoulder 15, and a stirring needle 12 is provided on the lower end surface of the shaft shoulder 15. A mounting portion 13 is provided on the stirring head. The mounting portion 13 is used to mount the stirring head on the rotating mechanism of the additive manufacturing equipment. In this embodiment, the mounting portion is specifically a drive flange, and a flange hole 14 is provided on the drive flange. The stirring head is cylindrical, and the feed hole extends along the axial direction of the stirring head and passes through both ends of the stirring head.

[0037] The pressing mechanism 200 includes two feeding barrels and a swinging mechanism 300 for driving the two feeding barrels to swing. The two feeding barrels are respectively a first feeding barrel 211 and a second feeding barrel 212. The two feeding barrels are arranged at an angle relative to each other. Both feeding barrels are located at the top of the stirring head. In order to facilitate the synchronous swinging of the two feeding barrels, the lower ends of the two feeding barrels are fixedly connected together, and the upper parts of the two feeding barrels are connected together through a connecting rod 45, so that the two feeding barrels become a whole.

[0038] To enhance the flexibility of the feed barrel during swinging, the agitator head has a hemispherical head portion 16, resulting in a hemispherical top surface 161 of the agitator head. A plurality of first universal ball joints are mounted on the lower end surface of the feed barrel. These first universal ball joints are spaced around the lower end surface of the feed barrel, and the feed barrel is supported on the agitator head via the universal ball joints. The first universal ball joints are not shown in the accompanying drawings.

[0039] In this embodiment, the angle α between the two feeding barrels is 40°. It can be understood that in other embodiments, the angle α can also be 30°, 35°, 45°, 50° or 60°. Of course, it can also be other angles between 30-60°.

[0040] Driven by the swing mechanism, the two feed cylinders can sequentially reach the feeding position. When either feed cylinder is in the feeding position, the inner cavity of the feed cylinder is coaxially arranged with the feed hole and is interconnected. A first piston cylinder 411 is fixedly mounted on the top of the first feed cylinder 211, and a second piston cylinder 412 is fixedly mounted on the top of the second feed cylinder 212. The first piston cylinder 411 and the second piston cylinder 412 are collectively referred to as the pressing piston cylinders, that is, each feed cylinder has a fixed pressing piston cylinder on its top.

[0041] The first piston rod 421 of the first piston cylinder 411 can extend into the inner cavity of the corresponding first feeding cylinder 211 to press the bar stock 80 in the first feeding cylinder into the discharge hole. The second piston rod 422 of the second piston cylinder 412 can extend into the inner cavity of the corresponding second feeding cylinder 212 to press the bar stock 80 in the second feeding cylinder into the discharge hole.

[0042] The cylinder barrels of the first piston cylinder and the second piston cylinder are both connected to the top of the corresponding feed cylinder by flanges. In this embodiment, the first piston cylinder and the second piston cylinder are both pneumatic piston cylinders. It is understood that in other embodiments, the first piston cylinder and the second piston cylinder can also be hydraulic piston cylinders or electric piston cylinders.

[0043] In this embodiment, the cross-sections of the feed hole and the bar are both square, and the side length of the cross-section of the bar is 0.5 mm shorter than that of the feed hole. It is understood that in other embodiments, the side length of the cross-section of the bar is 0.2 mm, 0.8 mm, or 1 mm shorter than that of the feed hole. This ensures that the bar can smoothly enter the feed hole while also allowing the stirring head to drive the bar to rotate synchronously.

[0044] In order to reduce the friction between the first piston rod and the second piston rod and the bar material, a second universal ball joint 43 is installed on the lower end surface of the first piston rod and the second piston rod.

[0045] In this embodiment, a support ring 18 is fixedly mounted on the mixing head 11. A support plate 31 is rotatably mounted on the support ring 18 via a slewing bearing 19. The support ring 18 is located above the mounting portion 13. The inner ring of the slewing bearing 19 is bolted to the upper side of the support plate, while the outer ring of the slewing bearing 19 is also bolted to the support plate 31. The support plate is provided with bolt holes 311 for mounting to the fixing mechanism of the additive manufacturing equipment. The support plate 31 is located above the mounting portion 13.

[0046] A support member 32 is fixedly installed on the upper side of the support plate 31. The support member 32 is L-shaped and specifically includes an end plate 321 and a vertical plate 322. The end plate is fixed to the upper side of the support plate by bolts, and the vertical plate extends upward in the vertical direction.

[0047] The swing mechanism 300 is fixedly mounted on the end plate 321. In this embodiment, the swing mechanism 300 includes a swing cylinder 35 and a swing frame 36. The swing cylinder 35 is specifically a rack and pinion swing cylinder. The swing frame 36 is generally L-shaped. One end of the swing frame is fixedly connected to the swing cylinder's swing table 351 via a countersunk bolt 37, and the other end of the swing frame is welded to the outer wall of the lower portion of the two feeding barrels.

[0048] Two arc-shaped angle steels 33 are welded to the side of the vertical plate 322 facing the feed barrel. These two angle steels 33 are arranged vertically, forming an arc-shaped groove between them. This arc-shaped groove forms a chute 331, the center of which lies on the central axis of the swing table. A horizontally extending slide rod 34 is welded to the outer wall of each feed barrel. The ends of the two slide rods 34, facing away from the feed barrel, are connected together to form a slider 341. This slip ring slides into the chute 331, and the slide rod is connected to the upper portion of the feed barrel, providing support for the barrel.

[0049] The feeding mechanism 500 is used to feed the bar material into the feeding tube. In this embodiment, the feeding mechanism 500 includes two feeding boxes 50, each corresponding to a feeding tube. A feed port 23 is provided on the side of each feeding tube facing away from the swing mechanism, and a discharge port 55 is provided on one side of the feeding box. The feeding box is fixedly mounted on the corresponding feeding tube, and the discharge port 55 is connected to the feed port 23. The feeding box extends in a direction perpendicular to the feed port of the corresponding feeding tube.

[0050] The feed box is equipped with a push mechanism. In this embodiment, the push mechanism includes a push plate 52 and a push piston cylinder 53 mounted on the side of the feed box away from the discharge port. The piston rod B531 of the push piston cylinder 53 freely passes through the piston rod hole in the feed box and is fixedly connected to the push plate 52. The space between the push plate and the discharge port forms a receiving chamber 51 for accommodating the bar stock 80. In this embodiment, the push piston cylinder is a pneumatic piston cylinder. It is understood that in other embodiments, the push piston cylinder can also be a hydraulic piston cylinder or an electric piston cylinder.

[0051] The feed box is rectangular and open at the top, facilitating the loading of bars 80 into the receiving chamber. The bars are loaded vertically into the chamber. The length of the feed box extends perpendicular to the feed opening, and the chamber can only accommodate a single row of bars 80, arranged perpendicularly to the feed opening. Driven by piston rod B531, the bars in the chamber are sequentially fed into their corresponding feed barrels.

[0052] For the convenience of description, the two feeding boxes are respectively referred to as a first feeding box and a second feeding box, wherein the first feeding box is installed on the first feeding cylinder, and the second feeding box is installed on the second feeding cylinder.

[0053] In order to ensure that the rod material can quickly enter the discharge hole after entering the feed barrel from the feed box, the bottom plate 54 of the feed box is as close to the bottom of the feed barrel as possible while ensuring a stable connection. In this embodiment, the distance between the lower end surface of the bottom plate and the lower end surface of the feed barrel is 5 mm to ensure the welding quality. Under normal circumstances, the distance between the lower end surface of the bottom plate and the lower end surface of the feed barrel is controlled between 3-10 mm. While ensuring firm welding, it can also avoid the feed box from interfering with the rotation of the feed barrel.

[0054] The control system is used to control the swing of the swing mechanism. In this embodiment, the control system includes a central processing unit 90, a first magnetic induction switch 91, a second magnetic induction switch 92, and a swing mechanism control unit 93 connected to the central processing unit 90. Corresponding to the first magnetic induction switch 91 and the second magnetic induction switch 92, a first induction magnetic ring is installed on the first piston of the first piston cylinder, and a second induction magnetic ring is installed on the second piston of the second piston cylinder; wherein:

[0055] The central processing unit is used to receive information from the first magnetic induction switch and the second magnetic induction switch, and issue control instructions according to the information to control the operation of the swing mechanism; the central processing unit is specifically a single chip microcomputer.

[0056] The first magnetic induction switch is used to sense the first induction magnetic ring to detect the stroke of the first piston and send information to the central processing unit.

[0057] The second magnetic induction switch is used to sense the second induction magnetic ring to detect the stroke of the second piston and send information to the central processing unit.

[0058] The swing mechanism control unit is used to control the operation of the swing mechanism so that the swing mechanism drives the two feeding cylinders to swing.

[0059] Since a swing cylinder is used to drive the feed barrel to swing in this embodiment, a solenoid valve is used as the swing mechanism control unit 93. The solenoid valve specifically adopts a pneumatic three-position four-way solenoid valve, and the air source 94 is connected to the air inlet 352 of the swing cylinder 35 through the solenoid valve.

[0060] During operation, when the first magnetic induction switch obtains a signal when the first piston moves to the set position, the signal is sent to the central processing unit. The central processing unit starts the solenoid valve according to the pre-setting and suspends the action of the first piston cylinder at the same time. The compressed air in the air source 94 enters an air inlet of the swing cylinder through the solenoid valve, starts the swing cylinder, and drives the two feeding barrels to swing, so that the second feeding barrel reaches the feeding position, and then starts the second piston cylinder, so that the second piston rod of the second piston cylinder extends downward, pressing down the rod material in the second feeding barrel.

[0061] When the second magnetic induction switch obtains the signal that the second piston moves to the set position, the signal is sent to the central processing unit, and the central processing unit starts the solenoid valve according to the pre-setting and suspends the action of the second piston cylinder at the same time. The compressed air in the air source 94 enters the other air inlet of the swing cylinder through the solenoid valve, starts the swing cylinder, and drives the two feeding barrels to swing, so that the first feeding barrel reaches the feeding position, and then starts the first piston cylinder, so that the first piston rod of the first piston cylinder extends downward, pressing down the bar material in the first feeding barrel.

[0062] When the second feeding tube reaches the feeding position, the first piston rod of the first piston cylinder is retracted, and the bar materials in the first feeding box are pushed by the pushing mechanism into the first feeding tube for standby use. When the first feeding tube reaches the feeding position, the second piston rod of the second piston cylinder is retracted, and the bar materials in the second feeding box are pushed by the pushing mechanism into the second feeding tube for standby use.

[0063] In this embodiment, the pusher piston cylinder is not connected to the control system because there is sufficient time to feed the bar material into the first and second feeding tubes, and rapid operation is not required. It is understood that in order to improve the efficiency of automated operation, in another embodiment, the control of the two pusher piston cylinders can also be connected to the control system.

[0064] The following describes an additive manufacturing method, which is performed using the aforementioned swing-type continuous feed friction stir additive manufacturing apparatus. The additive manufacturing method specifically includes the following steps:

[0065] (1) Place the shoulder on the surface of the area to be added to the substrate, so that the first feeding cylinder reaches the feeding position, and then feed the rod into the first feeding cylinder through the feeding mechanism. The first piston rod of the first piston cylinder pushes the rod in the first feeding cylinder downward until the rod is pressed against the surface of the area to be added, and the first piston cylinder is paused.

[0066] (2) Start the stirring head and allow the shaft shoulder and the upper surface of the substrate to frictionally preheat for 10-25 seconds. The rod rotates synchronously under the drive of the stirring head. In actual operation, the friction preheating time between the shaft shoulder and the upper surface of the substrate can be controlled at 10 seconds, 15 seconds, 20 seconds or 25 seconds.

[0067] (3) Start the first piston cylinder again. The first piston rod of the first piston cylinder pushes the rod to move downward, so that a forging force is generated between the rod and the area to be added on the substrate. At the same time, the stirring head is retracted upward by 1.0 mm and moves along the set path. The rod is thermally plasticized under the action of friction and flows out from the discharge hole. The stirring head is kept rotating and drives the rod to rotate synchronously. The rod is thermally plasticized and deposited on the substrate. Under the flattening action of the shoulder, an additive forming surface is formed, so that a single layer of material is stacked in the area to be added to form an additive manufacturing layer.

[0068] (4) When the top surface of the rod in the first feeding barrel drops to the level with the upper edge of the discharge hole, the first piston cylinder is paused, the swing mechanism is started, and the second feeding barrel reaches the feeding position. Then the second piston cylinder is started, and the second piston rod of the second piston cylinder pushes the rod in the second feeding barrel into the discharge hole and continues to push downward; the first piston rod of the first piston cylinder is retracted, and the feeding mechanism sends the rod into the first feeding barrel for use.

[0069] When the top surface of the rod in the first feeding barrel drops to be flush with the upper edge of the discharge hole, the first piston of the first piston cylinder reaches its set position. At this time, the first magnetic induction switch senses the first induction magnetic ring and sends information to the central processing unit. The central processing unit controls the action of the swing cylinder through the solenoid valve to drive the two feeding barrels to move, so that the second feeding barrel reaches the feeding position.

[0070] (5) When the top surface of the rod in the second feeding barrel drops to the level with the upper edge of the discharge hole, the second piston cylinder is paused, the swing mechanism is started, and the first feeding barrel reaches the feeding position, and then the first piston cylinder is started. The first piston rod of the first piston cylinder pushes the rod in the first feeding barrel into the discharge hole and continues to push downward; the second piston rod of the second piston cylinder is retracted, and the feeding mechanism feeds the rod into the second feeding barrel for standby use;

[0071] When the top surface of the bar material in the second feeding barrel drops to be flush with the upper edge of the discharge hole, the second piston of the second piston cylinder reaches its set position. At this time, the second magnetic induction switch senses the second induction magnetic ring and sends information to the central processing unit. The central processing unit controls the action of the swing cylinder through the solenoid valve to drive the two feeding barrels to move, so that the first feeding barrel reaches the feeding position.

[0072] (6) Repeat steps (4) and (5) to repeatedly stack a single layer of material in the area to be added, thereby achieving continuous manufacturing of the additive process until the required additive height is reached.

[0073] In other embodiments, step (4) may also be performed as follows:

[0074] When the top surface of the bar stock in the first feeding barrel drops to the level of the upper edge of the discharge hole, the first piston rod of the first piston cylinder is lifted upward, and the swing mechanism is simultaneously activated, causing the second feeding barrel to reach the feeding position. The second piston cylinder is then activated, and the second piston rod of the second piston cylinder pushes the bar stock in the second feeding barrel into the discharge hole and continues to push downward. When the first piston rod of the first piston cylinder retracts, it pauses and stands by, and the feeding mechanism feeds the bar stock into the first feeding barrel. In this method, when the top surface of the bar stock in the first feeding barrel drops to the level of the upper edge of the discharge hole, the first piston rod of the first piston cylinder is lifted upward, which can quickly create a distance between the lower end surface of the first piston rod and the stirring head, reducing wear.

[0075] Step (5) can also be performed as follows:

[0076] When the top surface of the bar material in the second feeding barrel drops to the level with the upper edge of the discharge hole, the second piston rod of the second piston cylinder is lifted upward, and the swing mechanism is simultaneously activated, causing the first feeding barrel to reach the feeding position. The first piston cylinder is then activated, and the first piston rod of the first piston cylinder pushes the bar material in the first feeding barrel into the discharge hole and continues to push downward. When the second piston rod of the second piston cylinder retracts, it pauses and stands by, and the feeding mechanism feeds the bar material into the second feeding barrel. In this method, when the top surface of the bar material in the second feeding barrel drops to the level with the upper edge of the discharge hole, the second piston rod of the second piston cylinder is lifted upward, which can quickly create a distance between the lower end surface of the second piston rod and the stirring head, reducing wear.

Claims

1. Swinging continuous feeding friction stir additive manufacturing device, characterized in that, The invention comprises a stirring mechanism, a pressing mechanism, a feeding mechanism and a control system; the stirring mechanism comprises a stirring head and a feeding hole formed in the stirring head, the feeding hole extending in a vertical direction, the lower end of the stirring head forming a shaft shoulder, and a stirring needle provided on the lower end surface of the shaft shoulder; a mounting portion is provided on the stirring head, the mounting portion being used to mount the stirring head on the rotating mechanism of the additive manufacturing equipment; the cross-sections of the feeding hole and the rod are both square, and the side length of the cross-section of the rod is 0.2-1 mm shorter than the side length of the cross-section of the feeding hole; The material pressing mechanism includes two feeding barrels and a swinging mechanism for driving the two feeding barrels to swing, the two feeding barrels are arranged to be relatively inclined, and the two feeding barrels are both located at the top of the stirring head. Driven by the swinging mechanism, the two feeding barrels can reach the feeding position in turn, and when any feeding barrel is at the feeding position, the inner cavity of the feeding barrel is coaxially arranged with the discharge hole and is connected to each other; corresponding to each feeding barrel, a pressing piston cylinder is fixedly installed on the top of the feeding barrel, and the piston rod of the pressing piston cylinder can extend into the corresponding feeding barrel to press the rod material in the feeding barrel into the discharge hole; the two feeding barrels are respectively the first feeding barrel and the second feeding barrel, and the two pressing piston cylinders are respectively the first piston cylinder and the second piston cylinder, the first piston cylinder is installed on the top of the first feeding barrel, and the second piston cylinder is installed on the top of the second feeding barrel; The feeding mechanism is used to feed the bar material into the feeding cylinder, and the control system is used to control the swing of the swing mechanism.

2. The swing-type continuous feeding friction stir additive manufacturing device according to claim 1, characterized in that: A supporting disk is rotatably mounted on the stirring head, and the swing mechanism is fixedly mounted on the supporting disk.

3. The swing-type continuous feeding friction stir additive manufacturing device according to claim 2, characterized in that: The swing mechanism includes a swing cylinder and a swing frame. The swing cylinder is fixedly mounted on the support plate. One end of the swing frame is fixedly connected to the swing table of the swing cylinder, and the other end of the swing frame is fixedly connected to the two feeding barrels.

4. The swing-type continuous feeding friction stir additive manufacturing device according to claim 3, characterized in that: A support member is also fixedly installed on the support plate, and a slide groove is provided on the side of the support member facing the feed barrel. A slide rod is slidably installed in the slide groove. The end of the slide rod away from the support member is fixed on the top of the feed barrel, and the swing frame is fixed on the bottom of the feed barrel.

5. The swing-type continuous feeding friction stir additive manufacturing device according to claim 1, characterized in that: The feeding mechanism includes two feeding boxes, each feeding box corresponds to a feeding tube, a feeding port is provided on the side of the feeding tube away from the swinging mechanism, and a discharging port is provided on one side of the feeding box. The feeding box is fixedly mounted on the corresponding feeding tube, and the discharging port is connected to the feeding port. The feeding box extends in a direction perpendicular to the feeding port; a pushing mechanism is provided on the feeding box, which is used to push the rod material in the feeding box into the feeding tube.

6. The swing-type continuous feeding friction stir additive manufacturing device according to claim 5, characterized in that: The pushing mechanism includes a pushing plate and a pushing piston cylinder installed on the side of the feeding box away from the discharge port. The piston rod of the pushing piston cylinder is fixedly connected to the pushing plate, and the space between the pushing plate and the discharge port becomes a accommodating chamber for accommodating the rods. The accommodating chamber can only accommodate one row of rods. Under the push of the pushing piston cylinder, the rods in the accommodating chamber can enter the corresponding feeding barrel in turn.

7. The swing-type continuous feeding friction stir additive manufacturing device according to claim 1, characterized in that: The stirring head is cylindrical, the discharge hole extends along the axial direction of the stirring head, and the top surface of the stirring head is hemispherical. A number of universal ball heads are installed on the lower end surface of the feeding barrel. The plurality of universal ball heads are arranged at intervals around the lower end surface of the feeding barrel, and the feeding barrel is supported on the stirring head via the universal ball heads.

8. The swing-type continuous feeding friction stir additive manufacturing device according to claim 1, characterized in that: The angle between the two feeding barrels is 30-60°.

9. The swing-type continuous feeding friction stir additive manufacturing device according to claim 1, characterized in that: A first induction magnetic ring is installed on the first piston of the first piston cylinder, and a second induction magnetic ring is installed on the second piston of the second piston cylinder; the control system includes a central processing unit, a first magnetic induction switch, a second magnetic induction switch and a swing mechanism control unit connected to the central processing unit, wherein: a central processing unit, configured to receive information from the first magnetic induction switch and the second magnetic induction switch, and issue control instructions based on the information to control the operation of the swing mechanism; a first magnetic induction switch, for sensing the first induction magnetic ring to detect the stroke of the first piston and send information to the central processing unit; a second magnetic induction switch, used for sensing the second induction magnetic ring to detect the stroke of the second piston and send information to the central processing unit; The swing mechanism control unit is used to control the operation of the swing mechanism so that the swing mechanism drives the two feeding cylinders to swing.

10. An additive manufacturing method, characterized in that: The method is carried out using the swing-type continuous feeding friction stir additive manufacturing device according to any one of claims 1 to 9, and the additive manufacturing method comprises the following steps: (1) Place the shoulder on the surface of the area to be added to the substrate, so that the first feeding cylinder reaches the feeding position, and then feed the rod into the first feeding cylinder through the feeding mechanism. The piston rod of the first piston cylinder pushes the rod in the first feeding cylinder downward until the rod is pressed against the surface of the area to be added, and the first piston cylinder is paused; (2) Start the stirring head to allow the shaft shoulder and the upper surface of the substrate to be preheated by friction for 10-25 seconds, and the rod rotates synchronously under the drive of the stirring head; (3) Start the first piston cylinder again, and the piston rod of the first piston cylinder pushes the rod to move downward, so that a forging force is generated between the rod and the area to be added on the substrate, and at the same time, the stirring head is retracted upward by 0.2-2.0 mm, and the stirring head is moved along the set path. The rod is thermally plasticized under the action of friction and flows out from the discharge hole. The stirring head is kept rotating and drives the rod to rotate synchronously. The rod is thermally plasticized and deposited on the substrate, and an additive forming surface is formed under the flattening action of the shoulder, so that a single layer of material is stacked in the area to be added, forming an additive manufacturing layer; (4) When the top surface of the rod in the first feeding cylinder drops to the level with the upper edge of the discharge hole, the first piston cylinder is paused, the swing mechanism is started, and the second feeding cylinder reaches the feeding position, and then the second piston cylinder is started. The piston rod of the second piston cylinder pushes the rod in the second feeding cylinder into the discharge hole and continues to push downward; the piston rod of the first piston cylinder is retracted, and the feeding mechanism feeds the rod into the first feeding cylinder; or When the top surface of the bar material in the first feeding barrel drops to be flush with the upper edge of the discharge hole, the piston rod of the first piston cylinder is lifted upward, and the swing mechanism is started at the same time, so that the second feeding barrel reaches the feeding position, and then the second piston cylinder is started, and the piston rod of the second piston cylinder pushes the bar material in the second feeding barrel into the discharge hole and continues to push downward; when the piston rod of the first piston cylinder retracts, it pauses and stands by, and the feeding mechanism feeds the bar material into the first feeding barrel; (5) When the top surface of the rod in the second feeding cylinder drops to the level with the upper edge of the discharge hole, the second piston cylinder is paused, the swing mechanism is started, and the first feeding cylinder reaches the feeding position. Then the first piston cylinder is started, and the piston rod of the first piston cylinder pushes the rod in the first feeding cylinder into the discharge hole and continues to push downward; Retract the piston rod of the second piston cylinder, and the feeding mechanism feeds the bar material into the second feeding cylinder; or When the top surface of the bar material in the second feeding barrel drops to be flush with the upper edge of the discharge hole, the piston rod of the second piston cylinder is lifted upward, and the swing mechanism is started at the same time, so that the first feeding barrel reaches the feeding position, and then the first piston cylinder is started, and the piston rod of the first piston cylinder pushes the bar material in the first feeding barrel into the discharge hole and continues to push downward; when the piston rod of the second piston cylinder retracts, it pauses and stands by, and the feeding mechanism feeds the bar material into the second feeding barrel; (6) Repeat steps (4) and (5) to repeatedly stack a single layer of material in the area to be added, thereby achieving continuous manufacturing of the additive process until the required additive height is reached.

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