Swing type continuous feeding friction stir additive manufacturing device and additive manufacturing method

Abstract

The invention provides a swing type continuous feeding friction stir additive manufacturing device. The swing type continuous feeding friction stir additive manufacturing device comprises a stirring mechanism, a pressing mechanism, a feeding mechanism and a control system. The stirring mechanism comprises a stirring head with a discharging hole, a shaft shoulder is arranged at the lower end of the stirring head, the pressing mechanism comprises two feeding barrels and a swing mechanism, the swing mechanism drives the feeding barrels to swing and reach the feeding position, pressing piston cylinders are fixedly mounted at the tops of the feeding barrels, and the feeding mechanism is used for feeding bars into the feeding barrels. The control system is used for controlling swinging of the swinging mechanism. The invention further discloses an additive manufacturing method adopting the friction stir additive manufacturing device. The two feeding barrels are alternately used, the time for bars to enter the discharging hole is shortened, due to the fact that the switching time of the two feeding barrels is short, the material adding system does not need to be paused, continuous work can be achieved, and the production efficiency is improved. And feeding interruption caused by a short interval between the two bars can be made up by utilizing the fluidity of the plasticized bars and the flattening effect of the shaft shoulder.

Description

Technical Field

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

[0002] In the existing friction stir additive deposition process, the materials used include rods, wires, powders and other types. Wires can be easily fed continuously, but due to their poor rigidity, they are easily squeezed out of the shoulder of the stirring head. Powders have the advantage of convenient composition configuration, but have high requirements for their particle size, resulting in high raw material costs, and the discharge port is easy to be blocked during the welding process. Rods have the advantages of low raw material costs and high effects, but their continuity in feeding is poor.

[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 top 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 mixing 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 top forging force until the next rod is pressed against the previous rod. When the top 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 a rod, such as improving the continuity of the rod feeding and thereby improving the quality of the deposited material. Summary of the invention

[0005] In order to solve the problem of continuity of rod material delivery 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 pressing mechanism, a feeding mechanism and a control system; the stirring mechanism includes a stirring head and a feeding hole formed in the stirring head, the feeding hole extends in a vertical direction, the lower end of the stirring head is formed as a shaft shoulder, and a stirring needle is arranged on the lower end surface of the shaft shoulder; a mounting portion is arranged on the stirring head, and the mounting portion is 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 material are both square, and the side length of the cross-section of the rod material is 0.2-1mm shorter than the side length of the cross-section of the feeding hole;

[0006] The material pressing mechanism comprises 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 located 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 material pressing piston cylinder is fixedly installed on the top of the feeding barrel, and the piston rod of the material 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 material 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 tube, and the control system is used to control the swing of the swing mechanism.

[0008] In the present application, two feeding barrels are used alternately to reduce the time for the next rod to enter the feeding 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 feeding 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 rod to the feeding hole. The switching time of the two feeding barrels determines the interval time when two adjacent bars enter the feeding hole. Under the condition of automatic control, the switching of the two feeding barrels can be completed within 0.01-0.03 seconds under normal circumstances. In the prior art, the piston rod of the pressing piston cylinder needs to be retracted before the next bar can be fed into the feeding system, resulting in a long interval time between two adjacent bars. The length of the interval time mainly depends on the length of the bar. The longer the bar, the longer the time it takes for the piston rod to complete the retraction, and the longer the time the additive system is suspended. After adopting the present application, since the switching time of the two feeding barrels is short, the additive system does not need to be suspended and can work continuously. The fluidity of the plasticized bar and the rolling effect of the shoulder can make up for the feeding interruption caused by the short 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 out of service due to a malfunction, the other pressing piston cylinder can be used to complete production using the existing production process, thereby avoiding waste caused by product scrapping due to inability to complete the product. Since the feeding barrel has no moving parts and is only a cylindrical component, the problem of its malfunction is generally not considered.

[0010] Furthermore, in order to facilitate the installation of the swing mechanism, a support plate is rotatably mounted on the stirring head, and the swing mechanism is fixedly mounted on the support plate. The support plate is used to facilitate the determination of the relative position between the swing mechanism and the stirring head, thereby improving the convenience of the operation, and there is no need to adjust the position between the feed barrel and the stirring head before each operation. The support plate is used to be fixed to the fixing mechanism of the additive manufacturing equipment.

[0011] Specifically, the swing mechanism includes a swing cylinder and a swing frame, wherein 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. The swing of the two feeding barrels can be conveniently controlled by the swing cylinder, wherein the swing frame mainly plays a transitional role, so that the swing table of the swing cylinder can be conveniently connected to the two feeding barrels.

[0012] Furthermore, in order to avoid shaking of the feeding barrel and the pressing piston cylinder and 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 of which corresponds to a feeding tube. A feeding port is provided on the side of the feeding tube away from the swing mechanism, and a discharging port is provided on one side of the feeding box. The feeding box is fixed 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, and the pushing mechanism 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, the continuity of production is guaranteed. Even if one of the feeding boxes fails, the production can be completed in the existing manner by relying on only the other feeding box, avoiding the scrapping of unfinished products.

[0014] Specifically, 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 holding chamber for holding the rods. The holding chamber can only hold one row of rods, and under the push of the pushing piston cylinder, the rods in the holding chamber can enter the corresponding feeding tube in sequence. The design is simple and practical, and the manufacturing cost is low. Since only one row of rods can be held in the holding chamber, the rods can be smoothly moved into the feeding tube. When multiple rows of rods are used, a special adjustment mechanism needs to be set at the discharge port to avoid mutual squeezing between the rods in the same row, so that they cannot enter the feeding tube, 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, and a plurality 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.

[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 operation efficiency will be reduced.

[0017] Furthermore, in order to improve the flexibility of the operation and improve the operation efficiency, 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 connected to the central processing unit, a second magnetic induction switch and a swing mechanism control unit, wherein:

[0018] A central processing unit, used for receiving information from the first magnetic induction switch and the second magnetic induction switch, and issuing control instructions according to the information to control the operation of the swing mechanism;

[0019] A first magnetic induction switch, used 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, used 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 carried out using any of the above-mentioned swing-type continuous feeding friction stir additive manufacturing devices, and the additive manufacturing method comprises the following steps:

[0023] (1) placing the shaft shoulder on the surface of the area to be added to the substrate, allowing the first feeding cylinder to reach the feeding position, and then feeding the rod into the first feeding cylinder through the feeding mechanism, and 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 allow the shaft shoulder and the upper surface of the substrate to be preheated by friction for 10-25 seconds, and the rod material 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 of 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 rolling action of the shoulder, so that a single layer of material is deposited in the area to be added, and an additive manufacturing layer is formed;

[0026] (4) When the top surface of the bar 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, 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 bar 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 into the first feeding cylinder; or

[0027] When the top surface of the bar 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 in the second feeding barrel into the discharge hole and continues to push downward; when the piston rod of the first piston cylinder is retracted, it pauses and stands by, and the feeding mechanism feeds the bar into the first feeding barrel;

[0028] (5) When the top surface of the bar 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, the first feeding cylinder reaches the feeding position, and then the first piston cylinder is started, the piston rod of the first piston cylinder pushes the bar 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 into the second feeding cylinder; or

[0029] When the top surface of the bar 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 in the first feeding barrel into the discharge hole and continues to push downward; when the piston rod of the second piston cylinder is retracted, it pauses and stands by, and the feeding mechanism feeds the bar 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 the present 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 feeding 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 to the feeding hole, thereby reducing the interval time between two adjacent bars entering the feeding hole. The switching time of the two feeding barrels determines the interval time between two adjacent bars. 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 prior art 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 rods, the movement speed of its piston rod is relatively slow. Depending on the length 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 two adjacent rods. The length of the interval 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 compensate 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, thereby avoiding the product being scrapped due to inability to complete, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic 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 feeding friction stir additive manufacturing device comprises a stirring mechanism 100, a pressing mechanism 200, a feeding mechanism 500 and a control system; the stirring mechanism 100 comprises a stirring head 11 and a feeding hole 17 formed in the stirring head, the feeding hole 17 extends in the vertical direction, the lower end of the stirring head 11 is formed as a shaft shoulder 15, and a stirring needle 12 is arranged on the lower end surface of the shaft shoulder 15; a mounting portion 13 is arranged on the stirring head, and 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 driving flange, and a flange hole 14 is opened on the driving flange. The stirring head is cylindrical, and the feeding 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 to be inclined 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 via a connecting rod 45, so that the two feeding barrels become a whole.

[0038] In order to improve the flexibility of the feeding barrel when swinging, the stirring head has a hemispherical head 16, so that the top surface 161 of the stirring head is hemispherical, and a plurality of first 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. In the accompanying drawings, the first universal ball heads are not shown.

[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 feeding cylinders can reach the feeding position in turn. When any feeding cylinder is at the feeding position, the inner cavity of the feeding cylinder is coaxially arranged with the feeding hole and is connected to each other. A first piston cylinder 411 is fixedly installed on the top of the first feeding cylinder 211, and a second piston cylinder 412 is fixedly installed on the top of the second feeding cylinder 212. The first piston cylinder 411 and the second piston cylinder 412 are collectively referred to as a pressing piston cylinder, that is, corresponding to each feeding cylinder, a pressing piston cylinder is fixedly installed on the top of the feeding cylinder.

[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 material 80 in the first feeding cylinder into the feeding 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 material 80 in the second feeding cylinder into the feeding hole.

[0042] The cylinder barrels of the first piston cylinder and the second piston cylinder are both connected to the top of the corresponding feeding cylinder by flange. In this embodiment, the first piston cylinder and the second piston cylinder are both pneumatic piston cylinders. It can be understood that in other embodiments, the first piston cylinder and the second piston cylinder can also be hydraulic piston cylinders or electric piston cylinders at the same time or one of them.

[0043] In this embodiment, the cross-sections of the feeding 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 cross-section of the feeding hole. It can be 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 cross-section of the feeding hole. While ensuring that the bar can smoothly enter the feeding hole, the stirring head can also 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 head 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 provided on the stirring head 11, and a support plate 31 is rotatably mounted on the support ring 18 via a slewing bearing 19, and the support ring 18 is located on the upper side of the mounting portion 13. The inner ring of the slewing bearing 19 is fixedly mounted on the upper side of the support plate via bolts, and the outer ring of the slewing bearing 19 is fixedly mounted on the support plate 31 via bolts. Bolt holes 311 for mounting on a fixing mechanism of an additive manufacturing device are provided on the support plate. The support plate 31 is located above the mounting portion 13.

[0046] A support member 32 is fixedly mounted 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, wherein the swing cylinder 35 is specifically a gear rack swing cylinder, and the swing frame 36 is roughly L-shaped, one end of the swing frame is fixedly connected to the swing table 351 of the swing cylinder through a countersunk bolt 37, and the other end of the swing frame is welded to the outer wall of the lower part of the two feeding barrels.

[0048] Two angle steels 33 are welded to the side of the vertical plate 322 facing the feed tube. The two angle steels 33 are arranged in the up-down direction and form an arc groove between the two angle steels 33. The arc groove forms a slide groove 331. The center of the slide groove 331 is located on the central axis of the swing table. A sliding rod 34 extending in the horizontal direction is welded to the outer wall of each of the two feed tubes. The two ends of the sliding rods 34 away from the feed tube are connected together to form a slider 341. The slip ring is slidably inserted into the slide groove 331. The sliding rod is connected to the upper part of the feed tube to provide support for the feed tube.

[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 feeding box 50 corresponds to a feeding tube, a feeding port 23 is provided on the side of the two feeding tubes 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 feeding port 23. The feeding box extends in a direction perpendicular to the feeding port on the corresponding feeding tube.

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

[0051] The feeding box is rectangular and has an open top, so that the rods 80 can be loaded into the receiving cavity. The rods are loaded into the receiving cavity in a vertical direction. The length direction of the feeding box extends in a direction perpendicular to the feeding port. The receiving cavity can only accommodate one row of rods 80, which are arranged in a direction perpendicular to the feeding port. Under the push of the piston rod B531, the rods in the receiving cavity can enter the corresponding feeding tube in sequence.

[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 allow the rod material to 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 5mm to ensure the welding quality. Normally, the distance between the lower end surface of the bottom plate and the lower end surface of the feed barrel is controlled between 3-10mm. While ensuring a firm welding, the feed box can also avoid 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 the swing cylinder is used to drive the feed tube to swing in this embodiment, an electromagnetic valve is used as the swing mechanism control unit 93. The electromagnetic valve specifically adopts a pneumatic three-position four-way electromagnetic valve. The air source 94 is connected to the air inlet 352 of the swing cylinder 35 through the electromagnetic 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 simultaneously suspends the action of the first piston cylinder. 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 when 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, and starts the swing cylinder. The swing cylinder 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 rod material in the first feeding barrel.

[0062] When the second feeding barrel reaches the feeding position, the first piston rod of the first piston cylinder is retracted, and the rods in the first feeding box are pushed by the pushing mechanism to enter the first feeding barrel for standby. When the first feeding barrel reaches the feeding position, the second piston rod of the second piston cylinder is retracted, and the rods in the second feeding box are pushed by the pushing mechanism to enter the second feeding barrel for standby.

[0063] In this embodiment, the push piston cylinder is not connected to the control system because there is sufficient time to feed the bar material into the first feeding cylinder and the second feeding cylinder, and there is no need for rapid operation. It can be understood that in order to improve the efficiency of automated operation, in another embodiment, the control of the two push piston cylinders can also be connected to the control system.

[0064] The following is an explanation of the additive manufacturing method, which is carried out using the above-mentioned swing-type continuous feeding friction stir additive manufacturing device. The additive manufacturing method specifically includes the following steps:

[0065] (1) The shaft shoulder is placed on the surface of the area to be added to the substrate, and the first feeding cylinder reaches the feeding position. Then, the rod is fed 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 to make the shaft shoulder and the upper surface of the substrate frictionally preheat for 10-25 seconds, and the rod material rotates synchronously under the drive of the stirring head. In specific work, 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) The first piston cylinder is started 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 of the substrate. At the same time, the stirring head is retracted upward by 1.0 mm and 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. Under the flattening action of the shoulder, an additive forming surface is formed, so that a single layer of material is deposited 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 be flush with the upper edge of the discharge hole, the first piston cylinder is paused, the swing mechanism is started, the second feeding barrel reaches the feeding position, and then the second piston cylinder is started. 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 feeds the rod into the first feeding barrel for standby use.

[0069] When the top surface of the rod in the first feeding barrel drops to be flush with the upper edge of the feeding 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 cylinder drops to be flush with the upper edge of the discharge hole, the second piston cylinder is paused, the swing mechanism is started, the first feeding cylinder 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 cylinder 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 cylinder for standby use;

[0071] When the top surface of the rod in the second feeding barrel drops to be flush with the upper edge of the feeding 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 in the following manner:

[0074] When the top surface of the bar in the first feeding barrel drops to the level with the upper edge of the feeding hole, the first 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 second piston rod of the second piston cylinder pushes the bar in the second feeding barrel into the feeding hole and continues to push downward; when the first piston rod of the first piston cylinder retracts, it pauses and waits, and the feeding mechanism feeds the bar into the first feeding barrel. In this way, when the top surface of the bar in the first feeding barrel drops to the level with the upper edge of the feeding 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 in the following manner:

[0076] When the top surface of the bar in the second feeding barrel drops to the level with the upper edge of the feeding hole, the second 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 first piston rod of the first piston cylinder pushes the bar in the first feeding barrel into the feeding hole and continues to push downward; when the second piston rod of the second piston cylinder retracts, it pauses and waits, and the feeding mechanism feeds the bar into the second feeding barrel. In this way, when the top surface of the bar in the second feeding barrel drops to the level with the upper edge of the feeding 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. A swing-type 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 extends in a vertical direction, the lower end of the stirring head is formed as a shaft shoulder, and a stirring needle is arranged on the lower end surface of the shaft shoulder; a mounting part is arranged on the stirring head, and the mounting part is 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 material are both square, and the side length of the cross section of the rod material is 0.2-1mm shorter than the side length of the cross section of the feeding hole; The material pressing mechanism comprises 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 located 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 material pressing piston cylinder is fixedly installed on the top of the feeding barrel, and the piston rod of the material 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 material 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 tube, 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 a 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 comprises 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 two feeding barrels.

4. The swing-type continuous feeding friction stir additive manufacturing device according to claim 3 is characterized in that: A support member is also fixedly installed on the support plate, 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, one 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 arranged on the side of the feeding tube away from the swinging mechanism, and a discharging port is arranged 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 arranged on the feeding box, and the pushing mechanism 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 sequence.

7. The swing-type continuous feeding friction stir additive manufacturing device according to claim 1, characterized in that: 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 plurality 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, used for receiving information from the first magnetic induction switch and the second magnetic induction switch, and issuing control instructions according to the information to control the operation of the swing mechanism; A first magnetic induction switch, used 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) placing the shaft shoulder on the surface of the area to be added to the substrate, allowing the first feeding cylinder to reach the feeding position, and then feeding the rod into the first feeding cylinder through the feeding mechanism, and 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 material 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 of 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 rolling action of the shoulder, so that a single layer of material is deposited in the area to be added, and an additive manufacturing layer is formed; (4) When the top surface of the bar 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, 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 bar 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 into the first feeding cylinder; or When the top surface of the bar 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 in the second feeding barrel into the discharge hole and continues to push downward; when the piston rod of the first piston cylinder is retracted, it pauses and stands by, and the feeding mechanism feeds the bar into the first feeding barrel; (5) When the top surface of the rod 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, the first feeding cylinder reaches the feeding position, and then the first piston cylinder is started. 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 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 in the first feeding barrel into the discharge hole and continues to push downward; when the piston rod of the second piston cylinder is retracted, it pauses and stands by, and the feeding mechanism feeds the bar 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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