Continuous feeding friction stir additive manufacturing device and additive manufacturing method

Abstract

The invention discloses a stirring friction additive manufacturing device with a continuous feeding function. The stirring friction additive manufacturing device comprises a stirring mechanism, a pressing mechanism, a feeding mechanism and a control system. The stirring mechanism comprises a stirring head and a discharging hole in the stirring head, a shaft shoulder is formed at the lower end of the stirring head, and the cross section of the discharging hole and the cross section of the bar are both square. The pressing mechanism comprises two charging barrels and a moving mechanism, and a switching hydraulic cylinder of the moving mechanism is used for driving the two charging barrel sets to reciprocate in the horizontal direction. A pressing piston cylinder is fixed at the top of each charging barrel; the feeding mechanism is used for feeding bars into the charging barrel, and the control system is used for controlling the movement of the moving mechanism; the invention further discloses an additive manufacturing method adopting the friction stir additive manufacturing device. The two charging barrels are alternately used, the time for a next bar to enter the discharging hole is shortened, switching of the two charging barrels can be completed within a short time under the condition that automatic control is adopted, and continuous work can be achieved.

Description

Technical Field

[0001] The invention relates to a continuous-feeding friction stir 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 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 device; 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 pressing mechanism includes two barrels and a moving mechanism, the two barrels extend in a vertical direction, and one of the barrels is located on one side of the first axis direction of the other barrel, the two barrels are fixedly connected together and form a barrel assembly, the moving mechanism has a switching hydraulic cylinder, and the switching hydraulic cylinder is used to drive the barrel assembly to reciprocate along the first axis direction; in the height direction, the two barrels are located on the upper side of the stirring head, and driven by the moving mechanism, the two barrels can reach the feeding position in turn, and when any barrel is located at the feeding position, the inner cavity of the barrel is coaxially arranged with the discharge hole and communicated with each other; corresponding to each barrel, a pressing piston cylinder is fixedly installed on the top of the barrel, and the piston rod of the pressing piston cylinder can extend into the corresponding barrel to press the rod material in the barrel into the discharge hole;

[0007] The two barrels are respectively a first barrel and a second barrel, the two pressing piston cylinders are respectively a first piston cylinder and a second piston cylinder, the first piston cylinder is installed on the top of the first barrel, and the second piston cylinder is installed on the top of the second barrel;

[0008] The feeding mechanism is used to feed the bar material into the barrel, and the control system is used to control the movement of the moving mechanism;

[0009] The first axis direction extends along the horizontal direction.

[0010] In the present application, the two 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 barrel in the working state drops to be flush with the upper edge of the feeding hole, the positions of the two barrels can be switched so that the other barrel reaches the feeding position and delivers the next rod to the feeding hole. The switching time of the two barrels determines the interval time when two adjacent rods enter the feeding hole. When automatic control is adopted, the switching of the two 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 rod can be fed into the feeding system, resulting in a longer interval time between 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 time the additive system is paused. After adopting the present application, since the switching time of the two 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.

[0011] In addition, since the present application provides two material 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 material barrel has no moving parts and is only a cylindrical component, the problem of its malfunction is generally not considered.

[0012] Furthermore, in order to facilitate the installation of the swing mechanism, a support plate is rotatably installed on the stirring head, and the material pressing mechanism is installed on the support plate. The support plate is used to facilitate the determination of the relative position between the material pressing mechanism and the stirring head, thereby improving the convenience of the operation, and there is no need to adjust the position between the 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.

[0013] Furthermore, to facilitate the installation of the cylinder, the moving mechanism also includes a support frame, which is fixedly mounted on the support plate, and the barrel assembly is slidably supported on the support frame. The cylinder of the switching hydraulic cylinder is fixedly mounted on the support frame, and the piston rod of the switching hydraulic cylinder extends along the first axis direction and is connected to the barrel assembly.

[0014] Furthermore, a bar support plate is installed on the top of the stirring head, the upper surface of the bar support plate is horizontal and forms a bar support surface, the top surface of the stirring head is horizontal, and the bar support surface is coplanar with the top surface of the stirring head. This design can prevent the barrel from getting stuck due to obstacles such as steps when driving the bar to move synchronously.

[0015] Specifically, the feeding mechanism includes two feeding boxes, each of which corresponds to a barrel, and the feeding box extends along the second axis direction. A feeding port is provided on the side of the barrel facing the second axis direction. The feeding box is fixed on the corresponding barrel, and the discharge port of the feeding box is connected 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 barrel. The second axis direction extends in the horizontal direction, and the second axis direction is perpendicular to the first axis direction. Since each barrel 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 way by relying on the other feeding box alone, avoiding the scrapping of unfinished products.

[0016] 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 receiving chamber for accommodating the rods; the rods are loaded into the receiving chamber along the vertical direction, and the rods are arranged in a row along the second axis direction. Under the push of the pushing piston cylinder, the rods in the receiving chamber can enter the corresponding barrel in turn. The design is simple and practical, and the manufacturing cost is low. Since only one row of rods can be accommodated in the receiving chamber, the rods can be smoothly moved into the barrel. When multiple rows of rods are used, a special adjustment mechanism needs to be set at the discharge port to avoid mutual squeezing between rods in the same row, so that they cannot enter the barrel and affect the normal operation.

[0017] Furthermore, in order to reduce the resistance of the barrel when it moves, the top end surface of the stirring head is horizontal, and in the vertical direction, there is a gap of 0.1-0.5 mm between the top end surface of the barrel and the stirring head.

[0018] 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 switching hydraulic cylinder control unit, wherein:

[0019] A central processing unit, used for receiving information from the first magnetic induction switch and the second magnetic induction switch, and issuing a control instruction according to the information to control the operation of the switching hydraulic cylinder;

[0020] 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;

[0021] 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;

[0022] The switching hydraulic cylinder control unit is used to control the operation of the switching hydraulic cylinder so that the switching hydraulic cylinder drives the two barrel assemblies to move back and forth.

[0023] Secondly, the present application also discloses an additive manufacturing method, which is carried out using the continuous feeding friction stir additive manufacturing device described in any one of the above items, and the additive manufacturing method comprises the following steps:

[0024] (1) placing the shaft shoulder on the surface of the area to be added to the substrate, allowing the first barrel to reach the feeding position, and then feeding the rod into the first barrel through the feeding mechanism, and the piston rod of the first piston cylinder pushes the rod in the first barrel downward until the rod is pressed against the surface of the area to be added, and the first piston cylinder is paused;

[0025] (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;

[0026] (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;

[0027] (4) When the top surface of the bar in the first barrel drops to be flush with the upper edge of the discharge hole, the first piston cylinder is paused, the moving mechanism is started, the second barrel 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 barrel 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 barrel;

[0028] (5) When the top surface of the bar in the second barrel drops to be flush with the upper edge of the discharge hole, the second piston cylinder is paused, the moving mechanism is started, the first barrel 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 barrel 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 barrel;

[0029] (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.

[0030] In this additive manufacturing method, two barrels are used alternately. When the top surface of the bar in the barrel in the working state drops to be flush with the upper edge of the feeding hole, the positions of the two barrels can be switched without retracting the piston rod of the pressing piston cylinder, so that the other 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 barrels determines the interval time between two adjacent bars. When automatic control is adopted, the switching of the two 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 rod material, the movement speed of its piston rod is relatively slow. Depending on the different lengths of the rod material, it usually takes 1-5 minutes for the piston rod to complete the retraction before the next rod material can be fed into the system, resulting in a longer interval time between two adjacent rods. The length of the interval time mainly depends on the length of the rod material. The longer the rod material, 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 between the two barrels is short, the additive system does not need to be paused and can work continuously. The fluidity of the plasticized rod material and the flattening effect of the shoulder can compensate for the feeding interruption caused by the short interval between the two rod materials.

[0031] In addition, since the present application provides two material 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 material barrel has no moving parts and is only a cylindrical component, the problem of its failure is generally not considered.

[0032] Again, the present application also discloses another additive manufacturing method, which is carried out using the continuous feeding friction stir additive manufacturing device described in any one of the above items, and the additive manufacturing method comprises the following steps:

[0033] (1) placing the shaft shoulder on the surface of the area to be added to the substrate, allowing the first barrel to reach the feeding position, and then feeding the rod into the first barrel through the feeding mechanism, and the piston rod of the first piston cylinder pushes the rod in the first barrel downward until the rod is pressed against the surface of the area to be added, and the first piston cylinder is paused;

[0034] (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;

[0035] (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;

[0036] (4) When the top surface of the bar in the first 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 moving mechanism is started at the same time, so that the second 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 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 into the first barrel;

[0037] (5) When the top surface of the bar in the second 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 moving mechanism is started at the same time, so that the first 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 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 into the second barrel;

[0038] (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.

[0039] In this additive manufacturing method, two barrels are used alternately. When the top surface of the bar in the barrel in the working state drops to be flush with the upper edge of the feeding hole, the positions of the two barrels can be switched, so that the other 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 barrels determines the interval time between two adjacent bars. When automatic control is adopted, the switching of the two 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 rod material, the movement speed of its piston rod is relatively slow. Depending on the different lengths of the rod material, it usually takes 1-5 minutes for the piston rod to complete the retraction before the next rod material can be fed into the system, resulting in a longer interval time between two adjacent rods. The length of the interval time mainly depends on the length of the rod material. The longer the rod material, 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 between the two barrels is short, the additive system does not need to be paused and can work continuously. The fluidity of the plasticized rod material and the flattening effect of the shoulder can compensate for the feeding interruption caused by the short interval between the two rod materials.

[0040] During the process of switching the positions of the two barrels, the piston rod of the pressing piston cylinder is retracted upward at the same time to improve the working efficiency.

[0041] In addition, since the present application provides two material 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 material 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

[0042] Figure 1 It is a structural schematic diagram of an embodiment of the present invention.

[0043] Figure 2 yes Figure 1 The view in the AA direction is simplified and the stirring head is not sectioned. DETAILED DESCRIPTION

[0044] Example 1

[0045] The following first describes the continuous feed friction stir additive manufacturing device, please refer to Figure 1 and Figure 2In the accompanying drawings, the direction of the first arrow X indicates the direction of the first axis, and the direction of the second arrow Y indicates the direction of the second axis. The first axis direction and the second axis direction both extend in the horizontal direction and are perpendicular to each other.

[0046] The continuous feeding friction stir additive manufacturing device includes a stirring mechanism 100, a pressing mechanism 700, a feeding mechanism 500 and a control system 900; the stirring mechanism 100 includes 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 is formed as a shaft shoulder 15, and a stirring needle 12 is arranged on the lower end surface of the shaft shoulder; a mounting portion 13 is arranged on the stirring head, and the mounting portion 13 is used to install the stirring head on the rotating mechanism of the additive manufacturing equipment. In this embodiment, the mounting portion 13 is specifically a driving flange, and a flange hole 14 is opened on the driving flange. The stirring head is cylindrical, the central axis of the stirring head 11 extends in the vertical direction, and the feeding hole extends along the axial direction of the stirring head and passes through both ends of the stirring head. The cross-sections of the feed hole and the rod 80 are both square, and the side length of the cross-section of the rod is 0.5mm shorter than that of the cross-section of the feed hole. It can be understood that in other embodiments, the side length of the cross-section of the rod can also be 0.2mm, 0.4mm, 0.8mm or 1mm shorter than that of the cross-section of the feed hole. Of course, it can be other distances between 0.1-1mm to reduce the friction between the rod and the inner wall of the feed hole, so that the rod can move smoothly downward along the feed hole and the stirring head can drive the rod to rotate synchronously.

[0047] The pressing mechanism 700 includes two barrels and a moving mechanism 600. The two barrels are respectively a first barrel 811 and a second barrel 812. The two barrels extend in a vertical direction, and the first barrel is located on one side of the first axis direction of the second barrel. The two barrels are fixedly connected together by a connecting member 713, and the two barrels together form a barrel assembly. In this embodiment, the connecting member 713 is made of a square tube, and the two barrels are respectively welded on opposite sides of the connecting member.

[0048] Corresponding to each barrel, a pressing piston cylinder is fixedly installed on the top of the barrel, and the piston rod of the pressing piston cylinder can extend into the corresponding barrel to press the bar material in the barrel downward into the discharge hole. The pressing piston cylinder on the first barrel 811 is called the first piston cylinder 711, and the pressing piston cylinder on the second barrel 812 is called the second piston cylinder 712. The cylinder barrels of the two pressing piston cylinders are fixedly installed on the top of the corresponding barrel by flange. In order to reduce the friction between the piston rods of the two pressing piston cylinders and the bar material, a first universal ball head 43 is installed on the lower end surface of the piston rod of each pressing piston cylinder.

[0049] 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.

[0050] The moving mechanism 600 includes a support frame 60 and a switching hydraulic cylinder 67. The support frame 60 includes a first vertical plate 61 and a second vertical plate 62 welded on the support plate 31. The first vertical plate 61 and the second vertical plate 62 are arranged on opposite sides of the stirring head 11 along the first axis direction. Two support plates 65 extending along the first axis direction are fixedly installed between the first vertical plate 61 and the second vertical plate 62. The two support plates are arranged at intervals along the second axis direction, and each support plate has an upwardly open slide groove 63.

[0051] A slider 64 is provided on both sides of the second axis direction of each pressing piston cylinder. The slider is connected to the cylinder barrel of the pressing piston cylinder via a connecting rod 66. The two ends of the connecting rod 66 are welded to the slider and the cylinder barrel of the pressing piston cylinder. The two sliding rings of each pressing piston cylinder are respectively slidably clamped in the slide groove 63 of a support plate 65, so that the barrel assembly is slidably supported on the support frame. That is, the pressing mechanism 700 is installed on the support plate 31 via the first vertical plate and the second vertical plate.

[0052] The third cylinder barrel 671 of the switching hydraulic cylinder 67 is fixedly mounted on the side of the second vertical plate 62 away from the first vertical plate 61, and the third cylinder barrel extends along the first axis direction, so that the third piston rod 672 of the switching hydraulic cylinder 67 extends along the first axis direction. The third piston rod 672 freely passes through the piston hole 621 on the second vertical plate 62 and is fixed to the cylinder barrel of the first piston cylinder 711. Driven by the switching hydraulic cylinder 67, the barrel assembly can reciprocate in the slide groove 63 along the first axis direction.

[0053] In the height direction, both barrels are located on the upper side of the stirring head. Driven by the switching hydraulic cylinder 67, the two barrels can reach the feeding position in turn. When any barrel is located at the feeding position, the inner cavity of the barrel is coaxially arranged with the discharge hole and is connected to each other. When the first barrel is located at the feeding position, the piston rod of the first pressing piston cylinder can extend downward into the first barrel to press the bar material in the first barrel into the discharge hole; when the second barrel is located at the feeding position, the piston rod of the second pressing piston cylinder can extend downward into the second barrel to press the bar material in the second barrel into the discharge hole.

[0054] In this embodiment, the top surface of the stirring head is horizontal, and a bar support plate 111 is installed on the top of the stirring head. The upper surface of the bar support plate 111 is horizontal and forms a bar support surface 112. The bar support surface 112 is coplanar with the top surface of the stirring head. A second universal ball head is installed on the lower end surface of the barrel of each barrel, and the barrel is pressed against the bar support surface 112 through the second universal ball head. In the drawings, the second universal ball head is not shown.

[0055] It is understood that in another embodiment, two barrels can be suspended so that there is a gap between the lower end surface of the barrel and the top surface of the stirring head, and the gap can be specifically set to 0.1mm, 0.3mm or 0.5mm, or other distances between 0.1-0.5mm. This is mainly to avoid friction between the barrel and the stirring head and ensure the flexibility of the barrel movement.

[0056] The feeding mechanism 500 is used to feed the rod material into the barrel. In this embodiment, the feeding mechanism 500 includes two feeding boxes 50, each feeding box 50 corresponds to a barrel, the feeding box extends along the second axis direction, and a feed port 23 is provided on the side of the barrel facing the second axis direction. The feeding box is fixed on the corresponding barrel, and the outlet 55 of the feeding box 50 is connected to the feed port 23.

[0057] Each feeding box 50 is provided with a pushing mechanism, which is used to push the bar materials in the feeding box into the barrel. In this embodiment, each 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, and the fourth piston rod 531 of the pushing piston cylinder freely passes through the side wall of the feeding box and is fixedly connected to the pushing plate 52. The space between the pushing plate and the discharge port becomes a receiving chamber 51 for receiving the bar materials; the bar materials 80 are loaded into the receiving chamber 51 along the vertical direction, and the bar materials are arranged in a row along the second axis direction. Under the push of the fourth piston rod 531 of the pushing piston cylinder, the bar materials in the receiving chamber can enter the corresponding barrel in sequence.

[0058] In order to allow the rod material to quickly enter the discharge hole after entering the barrel from the feed box, the bottom plate 54 of the feed box is as close to the bottom of the 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 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 barrel is controlled between 3-10mm. While ensuring a firm welding, the feeding box can also avoid interfering with the movement of the barrel.

[0059] In this embodiment, the two pressing piston cylinders and the two pushing piston cylinders are hydraulic piston cylinders.

[0060] The control system 900 is used to control the movement of the moving mechanism. In this embodiment, a first induction magnetic ring is installed on the first piston of the first piston cylinder 711, and a second induction magnetic ring is installed on the second piston of the second piston cylinder 712. The control system includes a central processing unit 90, a first magnetic induction switch 91, a second magnetic induction switch 92 and a switching hydraulic cylinder control unit 93 connected to the central processing unit 90, wherein:

[0061] A central processing unit, used for receiving information from the first magnetic induction switch and the second magnetic induction switch, and issuing a control instruction according to the information to control the operation of the switching hydraulic cylinder;

[0062] 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;

[0063] 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;

[0064] The switching hydraulic cylinder control unit is used to control the operation of the switching hydraulic cylinder so that the switching hydraulic cylinder drives the two barrel assemblies to move back and forth.

[0065] Since the switching hydraulic cylinder 67 is used to drive the barrel to move back and forth, a solenoid valve is used as the switching hydraulic cylinder control unit 93. The solenoid valve specifically adopts a three-position four-way solenoid valve. The hydraulic station 94 is connected to the two hydraulic interfaces of the switching hydraulic cylinder 67 through the solenoid valve.

[0066] During operation, when the first magnetic induction switch obtains the 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 hydraulic oil in the hydraulic station 94 enters the switching hydraulic cylinder through the solenoid valve, starts the switching hydraulic cylinder, and drives the two barrels to move toward the direction of the second vertical plate, so that the second 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 to press down the rod material in the second barrel. Figure 1 In the process, the second barrel is located at the feeding position.

[0067] 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 hydraulic oil in the hydraulic station 94 enters the switching hydraulic cylinder through the solenoid valve, starts the switching hydraulic cylinder, and drives the two barrels to move toward the direction of the first vertical plate, so that the first 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 barrel.

[0068] When the second barrel reaches the feeding position, the first piston rod of the first piston cylinder is retracted, and the bar material in the first feeding box is pushed by the fourth piston rod 531 of the corresponding pushing piston cylinder to enter the first barrel for standby. When the first barrel reaches the feeding position, the second piston rod of the second piston cylinder is retracted, and the bar material in the second feeding box is pushed by the fourth piston rod 531 of the corresponding pushing piston cylinder to enter the second barrel for standby. This is repeated to achieve continuous additive process.

[0069] 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 barrel and the second barrel, 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.

[0070] Example 2

[0071] The first additive manufacturing method is described below. The first additive manufacturing method is specifically carried out using the continuous feeding friction stir additive manufacturing device in Example 1. The additive manufacturing method includes the following steps:

[0072] (1) The shoulder is placed on the surface of the area to be added to the substrate, so that the first barrel reaches the feeding position, and then the rod is fed into the first barrel through the feeding mechanism. The first piston rod of the first piston cylinder pushes the rod in the first barrel downward until the rod is pressed against the surface of the area to be added, and the action of the first piston cylinder is stopped.

[0073] (2) Start the stirring head to make the shaft shoulder and the upper surface of the substrate frictionally preheat for 15 seconds, and the rod material rotates synchronously under the drive of the stirring head. In other embodiments, the time for friction preheating the shaft shoulder and the upper surface of the substrate can also be controlled to be 10 seconds, 20 seconds or 25 seconds, or any other time between 10-25 seconds.

[0074] (3) Start the first piston cylinder again, and the first piston rod of the first piston cylinder pushes the rod to move downward, so that the rod and the area to be added to the substrate are generated with a forging force, and the stirring head is retracted upward by 1.0 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, and the stirring head is kept rotating, and the rod is driven 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 deposited in the area to be added to form an additive manufacturing layer. In other embodiments, the distance that the stirring head is retracted upward can also be 0.2 mm, 0.5 mm, 1.0 mm5 or 2.0 mm, or other distances between 0.2-2.0 mm.

[0075] (4) When the top surface of the rod in the first barrel drops to be flush with the upper edge of the discharge hole, the action of the first piston cylinder is paused, the moving mechanism is started, the second 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 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 barrel.

[0076] (5) When the top surface of the rod in the second barrel drops to be flush with the upper edge of the discharge hole, the action of the second piston cylinder is paused, the moving mechanism is started, the first 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 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 barrel.

[0077] (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.

[0078] Example 3

[0079] The second additive manufacturing method is described below. The second additive manufacturing method is specifically carried out using the continuous feeding friction stir additive manufacturing device in Example 1. The additive manufacturing method includes the following steps:

[0080] (1) placing the shoulder on the surface of the area to be added to the substrate, allowing the first barrel to reach the feeding position, and then feeding the rod into the first barrel through the feeding mechanism, and the piston rod of the first piston cylinder pushes the rod in the first barrel downward until the rod is pressed against the surface of the area to be added, and the action of the first piston cylinder is stopped;

[0081] (2) Start the stirring head to make the shaft shoulder and the upper surface of the substrate frictionally preheat for 20 seconds, and the rod material rotates synchronously under the drive of the stirring head. In other embodiments, the time for frictionally preheating the shaft shoulder and the upper surface of the substrate can also be controlled to be 10 seconds, 15 seconds or 25 seconds, or any other time between 10-25 seconds.

[0082] (3) Start the first piston cylinder again, and the first piston rod of the first piston cylinder pushes the rod to move downward, so that the rod and the area to be added to the substrate are generated with a forging force, and the stirring head is retracted upward by 0.5 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, and the stirring head is kept rotating, and the rod is driven 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 deposited in the area to be added to form an additive manufacturing layer. In other embodiments, the distance that the stirring head is retracted upward can also be 0.2 mm, 0.8 mm, 1.0 mm5 or 2.0 mm, or other distances between 0.2-2.0 mm.

[0083] (4) When the top surface of the bar in the first barrel drops to be flush with the upper edge of the discharge hole, the first piston rod of the first piston cylinder is lifted upward, and the moving mechanism is started at the same time, so that the second barrel reaches the feeding position, and then the second piston cylinder is started. The second piston rod of the second piston cylinder pushes the bar in the second 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 into the first barrel.

[0084] (5) When the top surface of the bar material in the second barrel drops to be flush with the upper edge of the discharge hole, the second piston rod of the second piston cylinder is lifted upward, and the moving mechanism is started at the same time, so that the first barrel reaches the feeding position, and then the first piston cylinder is started. The first piston rod of the first piston cylinder pushes the bar material in the first 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 barrel.

[0085] (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.

Claims

1. A continuous feed 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 pressing mechanism includes two barrels and a moving mechanism, the two barrels extend in a vertical direction, and one of the barrels is located on one side of the first axis direction of the other barrel, the two barrels are fixedly connected together and form a barrel assembly, the moving mechanism has a switching hydraulic cylinder, and the switching hydraulic cylinder is used to drive the barrel assembly to reciprocate along the first axis direction; in the height direction, the two barrels are located on the upper side of the stirring head, and driven by the moving mechanism, the two barrels can reach the feeding position in turn, and when any barrel is located at the feeding position, the inner cavity of the barrel is coaxially arranged with the discharge hole and communicated with each other; corresponding to each barrel, a pressing piston cylinder is fixedly installed on the top of the barrel, and the piston rod of the pressing piston cylinder can extend into the corresponding barrel to press the rod material in the barrel into the discharge hole; The two barrels are respectively a first barrel and a second barrel, the two pressing piston cylinders are respectively a first piston cylinder and a second piston cylinder, the first piston cylinder is installed on the top of the first barrel, and the second piston cylinder is installed on the top of the second barrel; The feeding mechanism is used to feed the bar material into the barrel, and the control system is used to control the movement of the moving mechanism; The first axis direction extends along the horizontal direction.

2. The 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 material pressing mechanism is mounted on the supporting disk.

3. The continuous feeding friction stir additive manufacturing device according to claim 2, characterized in that: The moving mechanism also includes a support frame, which is fixedly mounted on the support plate, and the barrel assembly is slidably supported on the support frame. The cylinder barrel of the switching hydraulic cylinder is fixedly mounted on the support frame, and the piston rod of the switching hydraulic cylinder extends along the first axis direction and is connected to the barrel assembly.

4. The continuous feeding friction stir additive manufacturing device according to claim 3, characterized in that: A rod support plate is installed on the top of the stirring head. The upper surface of the rod support plate is horizontal and forms a rod support surface. The top end surface of the stirring head is horizontal, and the rod support surface is coplanar with the top end surface of the stirring head.

5. The continuous feeding friction stir additive manufacturing device according to claim 1, characterized in that: The feeding mechanism includes two feeding boxes, each of which corresponds to a barrel. The feeding box extends along the second axis direction, and a feed port is arranged on the side of the barrel facing the second axis direction. The feeding box is fixed on the corresponding barrel, and the discharge port of the feeding box is connected to the feed 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 barrel; the second axis direction extends along the horizontal direction, and the second axis direction is perpendicular to the first axis direction.

6. The 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 rods are loaded into the accommodating chamber vertically, and the rods are arranged in a row along the second axis. Under the push of the pushing piston cylinder, the rods in the accommodating chamber can enter the corresponding barrel in turn.

7. The continuous feed friction stir additive manufacturing device according to claim 1, characterized in that: The top end surface of the stirring head is horizontal, and in the vertical direction, there is a gap of 0.1-0.5 mm between the barrel and the top end surface of the stirring head.

8. The 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 switching hydraulic cylinder 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 a control instruction according to the information to control the operation of the switching hydraulic cylinder; 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 switching hydraulic cylinder control unit is used to control the operation of the switching hydraulic cylinder so that the switching hydraulic cylinder drives the two barrel assemblies to move back and forth.

9. An additive manufacturing method, characterized in that: The continuous feeding friction stir additive manufacturing device according to any one of claims 1 to 8 is used, 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 barrel to reach the feeding position, and then feeding the rod into the first barrel through the feeding mechanism, and the piston rod of the first piston cylinder pushes the rod in the first barrel 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 barrel drops to be flush with the upper edge of the discharge hole, the first piston cylinder is paused, the moving mechanism is started, the second barrel 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 barrel 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 barrel; (5) When the top surface of the bar in the second barrel drops to be flush with the upper edge of the discharge hole, the second piston cylinder is paused, the moving mechanism is started, the first barrel 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 barrel 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 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.

10. An additive manufacturing method, characterized in that: The continuous feeding friction stir additive manufacturing device according to any one of claims 1 to 8 is used, 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 barrel to reach the feeding position, and then feeding the rod into the first barrel through the feeding mechanism, and the piston rod of the first piston cylinder pushes the rod in the first barrel 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 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 moving mechanism is started at the same time, so that the second 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 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 into the first barrel; (5) When the top surface of the bar in the second 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 moving mechanism is started at the same time, so that the first 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 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 into the second 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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