A friction stir additive manufacturing apparatus and method of additive manufacturing thereof

Abstract

The application discloses a friction stir additive manufacturing device and an additive manufacturing method thereof, and the device comprises a pressure rod, a rotary joint, a top rod, a stirring shaft sleeve and a power head, the rotary joint is connected to the lower part of the pressure rod through a detachable connection mode, the top rod is connected to the lower part of the rotary joint through a detachable connection mode, the stirring shaft sleeve is internally provided with an inner cavity, the top rod is movably connected to the stirring shaft sleeve, the stirring shaft sleeve is arranged in the power head, the power head and the stirring shaft sleeve are connected through mechanical fastening, the rotary joint can realize high-speed rotation of the top rod without rotation of the pressure rod, the shaft sleeve is driven by the power head to rotate at high speed, and the internal rod and the top rod are driven to rotate at high speed simultaneously, the pressure rod applies pressure to the top rod through the rotary joint, the top rod transmits the pressure to the rod, the rod is extruded from the gap between the shaft sleeve and the base body under the condition of high-speed rotation and pressure application, and the extruded and plasticized rod at one end of the shaft sleeve is combined with the base body, so that a forming layer is obtained, and the friction stir device is greatly simplified.

Description

Technical Field

[0001] This invention relates to a friction stir additive manufacturing apparatus and a method for additive manufacturing thereof, belonging to the field of friction stir additive technology. Background Technology

[0002] Friction stir additive manufacturing (FSM) technology uses friction stirring and extrusion to plasticize and bond materials at temperatures below their melting points, offering advantages such as low temperature, low defect rate, and high efficiency. Conventional FSM primarily uses a motor to drive a pressure rod, which rotates in conjunction with a stirring needle, applying pressure to the bar stock to achieve additive forming. However, this method requires the pressure rod and the bar stock to move in tandem, resulting in a relatively complex and demanding mechanism design. Therefore, to address these issues, a friction stir additive manufacturing apparatus is proposed. Summary of the Invention

[0003] The purpose of this invention is to provide a friction stirring additive manufacturing apparatus to simplify the structure of the friction stirring additive manufacturing apparatus.

[0004] The technical solution adopted in this invention is: A friction stir additive manufacturing apparatus includes a pressure rod, a rotary joint, a push rod, a stirring sleeve, and a power head. The rotary joint is detachably connected to the lower part of the pressure rod, and the push rod is detachably connected to the lower part of the rotary joint. The stirring sleeve has an inner cavity, and the push rod is movably connected to the stirring sleeve. The stirring sleeve is disposed inside the power head, and the power head and the stirring sleeve are mechanically fastened together. The rotary joint includes an upper end, a first limiting block, a combined thrust bearing, a second limiting block, a cylindrical roller bearing, and a lower end. A lower end is provided below the upper end, with a protrusion at the lower end and a concave portion at the upper end. Both the protrusion at the upper end and the concave portion at the lower end are gradient structures. A cylindrical roller bearing is fitted at the lowest point of the protrusion and the lowest point of the recess at the lower end of the connector. The upper part of the protrusion at the upper end of the connector is fitted with the inner ring of the combined thrust bearing. The upper part of the inner ring of the combined thrust bearing contacts the shoulder end face of the gradient structure of the protrusion at the upper end of the connector. A second limiting block is provided below the inner ring of the combined thrust bearing. The inner hole of the second limiting block and the contact part of the protrusion at the upper end of the connector are threaded and connected by the thread. The outer ring of the combined thrust bearing is fitted with the recess at the lower end of the connector. The lower part of the outer ring of the combined thrust bearing contacts the shoulder end face of the gradient structure of the recess at the lower end of the connector. A first limiting block is provided above the outer ring of the combined thrust bearing. The outer side of the first limiting block and the contact part of the uppermost inner side of the recess at the lower end of the connector are threaded and connected by the thread.

[0005] Preferably, the upper end of the connector is threadedly connected to the pressure rod by a screw, and the lower end of the connector is threadedly connected to the top rod by a screw.

[0006] Preferably, the pressure rod is round and connected to an external hydraulic cylinder or an external motor. The diameter of the pressure rod is 30-100mm, the telescopic range is 10-2000mm, the axial pressure provided by the pressure rod is 0-100000N, and the telescopic speed is 0-50mm / s.

[0007] Preferably, the rotary joint has a rotational speed range of 0-5000 rpm and a bearing axial force range of 0-100000 N.

[0008] Preferably, the inner cavity of the stirring shaft sleeve has a square cross-sectional shape, with a side length of 5-35mm, an outer diameter of 30-100mm, and a length of 150-2200mm. A shoulder is provided at the connection between the stirring shaft sleeve and the power head, and the lower end of the stirring shaft sleeve adopts a gradient structure.

[0009] Preferably, the top rod has a square cross-section, with a side length of 5-35mm and a length of 100-2000mm, and the top rod is made of cemented carbide.

[0010] The present invention also provides a method for additive manufacturing using the above-described friction stir additive manufacturing apparatus, characterized by comprising the following steps: 1) Load the bar stock into the mixing shaft sleeve until the upper end of the bar stock contacts the lower end of the push rod; 2) Install the workpiece under the bar stock, and make the lower end of the bar stock contact the surface of the workpiece to be additively processed; 3) Start the power head, which drives the mixing shaft sleeve to rotate at high speed. The mixing shaft sleeve drives the bar stock and the push rod to rotate at high speed. At the same time, start the external hydraulic cylinder or external motor above the pressure rod. The external hydraulic cylinder or external motor drives the pressure rod to apply downward pressure. The pressure rod transmits the downward pressure to the rotary joint and the push rod, and then transmits the downward pressure to the bar stock. 4) The push rod rotates at high speed under the drive of the stirring shaft sleeve, and transmits the rotational motion to the lower end of the joint inside the rotary joint. With the combination of thrust bearing and cylindrical roller bearing, the high-speed rotation of the lower end of the joint will not be transmitted to the upper end of the joint, and thus will not be transmitted to the pressure rod. 5) The bar stock is squeezed out from the gap between the stirring shaft sleeve and the workpiece under high speed and pressure. After being squeezed and plasticized by one end of the stirring shaft sleeve, it combines with the workpiece to obtain a shaped layer.

[0011] Preferably, the bar material can be aluminum alloy, magnesium alloy, titanium alloy and other alloy materials, the bar cross-section is square, the side length of the cross-section is 5-35mm and the length is 10-2000mm.

[0012] Preferably, the side lengths of the top rod section, the inner cavity section of the stirring shaft sleeve, and the bar section are set accordingly.

[0013] The beneficial effects of this invention are: 1. The rotary joint structure of this invention uses a combination of thrust bearings and cylindrical roller bearings to divide the rotary joint into an upper end and a lower end. During operation, the high-speed rotation of the lower end of the joint will not be transmitted upward to the upper end, achieving high-speed rotation of the push rod while the pressure rod does not rotate. The structure of the rotary joint simplifies the friction stirring additive manufacturing design. 2. The connection between the stirring shaft sleeve and the power head of this invention is provided with a shoulder to facilitate the transmission of axial force. The lower end of the stirring shaft sleeve adopts a gradient structure to facilitate friction stirring additive manufacturing. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the friction stir additive manufacturing apparatus described in this invention.

[0015] Figure 2 This is a schematic diagram of the rotary joint.

[0016] Figure 3 This is a schematic diagram of the structure of the stirring shaft sleeve.

[0017] In the picture: 1. Pressure rod; 2. Rotary joint; 21. Screw; 22. Upper end of joint; 23. First limiting block; 24. Combined thrust bearing; 25. Second limiting block; 26. Cylindrical roller bearing; 27. Lower end of joint; 3. Push rod; 4. Stirring bushing; 5. Power head; 6. Forming layer; 7. Workpiece. Detailed Implementation

[0018] The following is in conjunction with the appendix of this invention. Figure 1-3 The technical solutions in the embodiments of the present invention will be clearly and completely described.

[0019] Figure 1The diagram shows the overall structure of the friction stir additive manufacturing device. The device includes a pressure rod 1, a rotary joint 2, a push rod 3, a stirring sleeve 4, and a power head 5. The pressure rod 1 is mechanically connected to the rotary joint 2, and the rotary joint 2 is mechanically connected to the push rod 3. The stirring sleeve 4 has an inner cavity with a square cross-section, a side length of 5-35 mm, an outer diameter of 30-100 mm, and a length of 150-2200 mm. The push rod 3 is movably connected to the stirring sleeve 4. The push rod 3 also has a square cross-section, a side length of 5-35 mm, and a length of 100-2000 mm. The side lengths of the push rod 3 and the inner cavity of the stirring sleeve 4 are correspondingly set. The stirring sleeve 4 is housed within the power head 5, and the power head 5 and the stirring sleeve 4 are mechanically fastened together. The pressure rod 1 is a round rod and is connected to an external hydraulic cylinder or an external motor. During operation, the external hydraulic cylinder or external motor drives the pressure rod 1 to apply downward pressure. The pressure rod 1 transmits the downward pressure to the rotary joint 2 and the push rod 3. The pressure rod 1 can move in the axial direction and has the function of transmitting downward pressure. The diameter of the pressure rod 1 is 30-100mm. During operation, the extension range of the pressure rod 1 is 10-2000mm. The axial pressure range provided by the pressure rod 1 is 0-100000N, and the extension speed range is 0-50mm / s. The push rod 3 is made of hard alloy.

[0020] The structure of the rotary joint 2 is as follows: Figure 2As shown, the connector includes an upper end 22, a first limiting block 23, a combined thrust bearing 24, a second limiting block 25, a cylindrical roller bearing 26, and a lower end 27. The lower end 27 is located below the upper end 22. The lower end of the upper end 22 has a protrusion, and the upper end of the lower end 27 has a recess. Both the protrusion of the upper end 22 and the recess of the lower end 27 are gradient structures. The cylindrical roller bearing 26 is connected to the lowest point of the protrusion of the upper end 22 and the lowest point of the recess of the lower end 27. The upper part of the protrusion of the upper end 22 is connected to the inner ring of the combined thrust bearing 24. The upper part of the inner ring of the combined thrust bearing 24 contacts the shoulder end face of the gradient structure of the protrusion of the upper end 22. The second limiting block 25 is located below the inner ring of the combined thrust bearing 24. The inner hole of the second limiting block 25 and... The convex contact portion of the upper end 22 of the connector is threaded, and the two are connected by the thread. The outer ring of the combined thrust bearing 24 is connected to the recess of the lower end 27 of the connector. The lower part of the outer ring of the combined thrust bearing 24 contacts the shoulder end face of the gradient structure of the recess of the lower end 27 of the connector. A first limiting block 23 is provided above the outer ring of the combined thrust bearing 24. The outer side of the first limiting block 23 and the uppermost inner side of the recess of the lower end 27 of the connector are threaded, and the two are connected by the thread. The first limiting block 23 and the second limiting block 25 cooperate with the convex shoulder of the upper end 22 of the connector and the recess shoulder of the lower end 27 of the connector to limit the combined thrust bearing 24. The upper end of the upper end 22 of the connector can be detached by being threadedly connected to the pressure rod 1 by screw 21. The lower part of the lower end 27 of the connector and the push rod 3 can be detached by being threadedly connected by screw 21. Figure 1 It can be seen that during operation, the power head 5 drives the stirring shaft sleeve 4 to rotate at high speed. The stirring shaft sleeve 4 transmits the high-speed rotational motion upwards and downwards. Upwards, it is transmitted to the rotary joint 2 through the transmission push rod 3. The rotational speed range of the rotary joint 2 is 0-5000 rpm, and the axial force range is 0-100000 N. The lower end 27 of the rotary joint 2 rotates at high speed. Due to the combination of the thrust bearing 24 and the cylindrical roller bearing 26, the high-speed rotation of the lower end 27 of the joint will not be transmitted to the upper end 22 of the joint, and thus the high-speed rotation will not be transmitted. The motion is transmitted to the pressure rod 1, so that the pressure rod 1 does not rotate while the push rod 3 rotates at high speed. At the same time, the stirring sleeve 4 transmits the high-speed rotational motion downward. During operation, the stirring sleeve 4 contains a bar stock, which rotates at high speed along with the stirring sleeve 4. Combined with the downward pressure provided by the external hydraulic cylinder or external motor drive above the pressure rod 1, the bar stock is squeezed out from the gap between the stirring sleeve 4 and the workpiece 7 under high-speed rotation and pressure. After being squeezed and plasticized at one end of the stirring sleeve 4, it combines with the workpiece 7 to obtain the forming layer 6.

[0021] like Figure 3As shown, the connection between the stirring shaft sleeve 4 and the power head 5 is provided with a shoulder to facilitate the transmission of axial force. The lower end of the stirring shaft sleeve 4 adopts a gradient structure to facilitate friction additive manufacturing.

[0022] The present invention also provides a method for additive manufacturing using the above-described friction stir additive manufacturing apparatus, comprising the following steps: 1) Load the bar stock into the mixing shaft sleeve 4 until the upper end of the bar stock contacts the lower end of the push rod 3; 2) Install workpiece 7 under the bar stock, and make the lower end of the bar stock contact the surface of workpiece 7 to be added; 3) Start the power head 5. The power head 5 drives the stirring shaft sleeve 4 to rotate at high speed. The stirring shaft sleeve 4 drives the bar and the push rod 3 to rotate at high speed. At the same time, start the external hydraulic cylinder or external motor above the pressure rod 1. The external hydraulic cylinder or external motor drives the pressure rod 1 to apply downward pressure. The pressure rod 1 transmits the downward pressure to the rotary joint 2 and the push rod 3, and then transmits the downward pressure to the bar. 4) The push rod 3 rotates at high speed under the drive of the stirring shaft sleeve 4, and transmits the rotational motion to the lower end 27 of the joint inside the rotary joint 2. With the combination of the thrust bearing 24 and the cylindrical roller bearing 26, the high-speed rotation of the lower end 27 of the joint will not be transmitted to the upper end 22 of the joint, and thus will not be transmitted to the pressure rod 1. 5) The bar stock is squeezed out from the gap between the stirring shaft sleeve 4 and the workpiece 7 under high speed rotation and pressure. After being squeezed and plasticized by one end of the stirring shaft sleeve 4, it combines with the workpiece 7 to obtain the forming layer 6.

[0023] In the friction stir additive manufacturing process, the added bar material can be aluminum alloy, magnesium alloy, titanium alloy and other alloy materials. The bar cross-section is square with a side length of 5-35mm and a length of 10-2000mm. The side length of the bar cross-section is set to correspond to the side length of the push rod 3 and the side length of the inner cavity of the stirring shaft sleeve 4. The side length of the bar cross-section, the side length of the push rod 3 and the side length of the inner cavity of the stirring shaft sleeve 4 are determined according to the actual working needs.

[0024] The examples described are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the protection scope of the present invention.

Claims

1. A friction stir additive manufacturing apparatus, comprising a pressure rod (1), a rotary joint (2), a push rod (3), a stirring shaft sleeve (4), and a power head (5), characterized in that: The pressure rod (1) is connected to the rotary joint (2) via a detachable connection. The rotary joint (2) is connected to the top rod (3) via a detachable connection. The stirring shaft sleeve (4) has an inner cavity. The top rod (3) is movably connected to the stirring shaft sleeve (4). The stirring shaft sleeve (4) is located inside the power head (5). The power head (5) and the stirring shaft sleeve (4) are mechanically fastened together. The rotary joint (2) includes an upper end (22), a first limiting block (23), a combined thrust bearing (24), a second limiting block (25), a cylindrical roller bearing (26), and a lower end (27). The lower end (27) is located below the upper end (22). The lower end of the upper end (22) has a protrusion, and the upper end (27) has a concave part. The protrusion of the upper end (22) and the concave part of the lower end (27) are both set as a gradient structure. The lowermost part of the protrusion of the upper end (22) and the lower end of the joint are set as a gradient structure. A cylindrical roller bearing (26) is fitted to the bottom of the recess of part (27). The upper part of the convex part of the upper end of the connector (22) is fitted to the inner ring of the combined thrust bearing (24). The upper part of the inner ring of the combined thrust bearing (24) is in contact with the shoulder end face of the convex gradient structure of the upper end of the connector (22). A second limiting block (25) is provided below the inner ring of the combined thrust bearing (24). The inner hole of the second limiting block (25) and the contact part of the convex part of the upper end of the connector (22) are threaded and connected by the thread. The outer ring of the combined thrust bearing (24) is fitted to the recess of the lower end of the connector (27). The lower part of the outer ring of the combined thrust bearing (24) is in contact with the shoulder end face of the recess gradient structure of the lower end of the connector (27). A first limiting block (23) is provided above the outer ring of the combined thrust bearing (24). The outer side of the first limiting block (23) and the contact part of the uppermost inner side of the recess of the lower end of the connector (27) are threaded and connected by the thread. The inner cavity of the stirring shaft sleeve (4) is square, with a side length of 5-35mm, an outer diameter of 30-100mm, and a length of 150-2200mm. A shoulder is provided at the connection between the stirring shaft sleeve (4) and the power head (5), and the lower end of the stirring shaft sleeve (4) adopts a gradient structure.

2. The friction stir additive manufacturing apparatus according to claim 1, characterized in that: The upper end (22) of the connector is threadedly connected to the pressure rod (1) by a screw (21), and the lower end (27) of the connector is threadedly connected to the top rod (3) by a screw (21).

3. The friction stir additive manufacturing apparatus according to claim 1, characterized in that: The pressure rod (1) is a round rod and is connected to an external hydraulic cylinder or an external motor. The diameter of the pressure rod (1) is 30-100mm, the telescopic range is 10-2000mm, the axial pressure provided by the pressure rod (1) is 0-100000N, and the telescopic speed range is 0-50mm / s.

4. The friction stir additive manufacturing apparatus according to claim 1, characterized in that: The rotary joint (2) has a rotational speed range of 0-5000 rpm and a bearing axial force range of 0-100000N.

5. The friction stir additive manufacturing apparatus according to claim 1, characterized in that: The top rod (3) has a square cross-section, with a side length of 5-35mm and a length of 100-2000mm. The material of the top rod (3) is hard alloy.

6. The method for additive manufacturing using the friction stir additive manufacturing apparatus according to any one of claims 1-5, characterized in that: 1) Load the bar stock into the mixing shaft sleeve (4) until the upper end of the bar stock contacts the lower end of the top rod (3); 2) Install the workpiece (7) under the bar stock and make the lower end of the bar stock contact the surface of the workpiece (7) to be added; 3) Start the power head (5), the power head (5) drives the stirring shaft sleeve (4) to rotate at high speed, the stirring shaft sleeve (4) drives the bar and the push rod (3) to rotate at high speed; at the same time, start the external hydraulic cylinder or external motor above the pressure rod (1), the external hydraulic cylinder or external motor drives the pressure rod (1) to apply downward pressure, the pressure rod (1) transmits the downward pressure to the rotary joint (2) and the push rod (3), and then transmits the downward pressure to the bar; 4) The push rod (3) rotates at high speed under the drive of the stirring shaft sleeve (4) and transmits the rotational motion to the lower end (27) of the joint in the rotary joint (2). With the combination of the thrust bearing (24) and the cylindrical roller bearing (26), the high-speed rotation of the lower end (27) of the joint will not be transmitted to the upper end (22) of the joint, and thus will not transmit the high-speed rotational motion to the pressure rod (1). 5) The bar stock is squeezed out from the gap between the stirring sleeve (4) and the workpiece (7) under high speed rotation and pressure. After being plasticized by the extrusion at one end of the stirring sleeve (4), it is combined with the workpiece (7) to obtain the forming layer (6).

7. The method for additive manufacturing using the friction stir additive manufacturing apparatus according to claim 6, characterized in that, The bar stock material can be aluminum alloy, magnesium alloy, titanium alloy and other alloy materials. The bar stock cross-section is square, with a side length of 5-35mm and a length of 10-2000mm.

8. The method for additive manufacturing using the friction stir additive manufacturing apparatus according to claim 6, characterized in that, The dimensions of the top rod (3), the inner cavity of the stirring shaft sleeve (4), and the bar material are set accordingly.

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