Wire stirring friction material adding device with backpressure support

Abstract

The wire stirring friction material adding device with the back pressure supporting function comprises a material adding part and a supporting part, the material adding part comprises a static shaft shoulder and a stirring shaft which are arranged together in an inserted mode, a spiral channel is formed between a spiral rod and the static shaft shoulder, and a wire feeding hole communicated with the spiral channel is formed in the static shaft shoulder; the supporting part comprises a thrust ball bearing installed on the shaft shoulder, a bearing structure installed on the thrust ball bearing and a back pressure supporting structure installed on the bearing structure. The bearing structure is detachably mounted on a shaft washer of the thrust ball bearing; a supporting shaft of the backpressure supporting structure is installed on the hanging rod in a sliding mode, and the supporting shaft is rotationally sleeved with a supporting roller. According to the wire stirring friction material adding device, the bearing mechanism and the back pressure supporting structure can be detached from the material adding part together, so that the wire stirring friction material adding device can conduct conventional workpiece machining, after the bearing structure and the back pressure supporting structure are installed, material adding machining can be conducted on a workpiece needing back pressure supporting, and collapse of a corresponding area is avoided.

Description

Technical Field

[0001] This invention belongs to the field of friction stir additive manufacturing, specifically relating to a wire friction stir additive manufacturing device with back pressure support. Background Technology

[0002] When using a friction stir additive manufacturing device with filament as raw material, the substrate needs to be placed on the worktable first, and then additive manufacturing is performed. During additive manufacturing, the downward pressure generated by the stirring needle is transmitted to the worktable. The worktable acts as a support mechanism and provides back pressure reaction force to balance the downward pressure of the stirring needle. Therefore, the shape of the workpiece is relatively regular, mainly flat or ring-shaped. When the shape of the workpiece tends to be more complex, it is necessary to first make a regular flat or ring-shaped workpiece, and then perform cutting to perform subtraction operation, which leads to a decrease in work efficiency.

[0003] When a recessed structure is provided on the bottom of the workpiece, a corresponding recessed structure needs to be provided in the corresponding area of ​​the substrate. The area corresponding to this recessed structure cannot independently support the downward pressure of the stirring pin, causing the area to collapse and affecting the smooth progress of the additive manufacturing process. Therefore, a matching support structure is required. Since different workpieces require different support structures, a large number of support structures are needed, severely restricting the application of the friction stir additive manufacturing method. Summary of the Invention

[0004] To address the problem in existing technologies where a recessed area at the bottom of a workpiece cannot independently support the downward pressure of the stirring needle, leading to collapse in that area, this application proposes a wire stirring friction additive manufacturing device with back pressure support. The device includes an additive manufacturing section and a support section. The additive manufacturing section includes a stationary shoulder and a stirring shaft. The stationary shoulder has an inner cavity. The stirring shaft includes a helical rod and a drive shaft connected to the upper side of the helical rod. The helical rod is inserted into the inner cavity of the stationary shoulder, forming a helical channel between the helical rod and the stationary shoulder. A wire feeding hole communicating with the helical channel is provided on the stationary shoulder.

[0005] The support includes a thrust ball bearing, a load-bearing structure, and a back pressure support structure. The seat ring of the thrust ball bearing is fixed on the stationary shaft shoulder. The load-bearing structure is detachably mounted on the shaft ring of the thrust ball bearing. The back pressure support structure is mounted on the load-bearing structure and is located below the stirring shaft.

[0006] The load-bearing structure includes two opposing suspension rods that extend vertically, with the upper ends of the suspension rods detachably mounted on the shaft ring of a thrust ball bearing. The back pressure support structure includes a support shaft and a support roller. The two ends of the support shaft are slidably mounted on a suspension rod and can reciprocate vertically. The support roller is rotatably sleeved on the support shaft.

[0007] In this application, the supporting structure is detachably mounted on the shaft ring, allowing the supporting mechanism and other components mounted on the supporting structure to be removed from the additive manufacturing unit. This enables the wire stirring friction additive manufacturing device of this application to perform conventional workpiece processing. After installing the supporting structure and its connected components, additive manufacturing can be performed on workpieces requiring back pressure support, preventing collapse in the corresponding area. By adjusting the position of the support shaft on the hanger, the distance between the support roller and the stationary shoulder can be adjusted to accommodate substrates of different thicknesses and different additive thicknesses. After completing the processing of one additive layer, the position of the support roller on the hanger is adjusted, and the additive manufacturing unit is simultaneously lifted upwards until the distance between the stationary shoulder and the uppermost additive layer reaches the thickness of one additive layer. The support roller is then supported on the lower surface of the substrate, and the formation of the next additive layer continues. This process is repeated until the entire component is produced. The additive layer is also called a deposited layer.

[0008] When it is necessary to adjust the orientation of the support relative to the additive manufacturing part, the entire support can be rotated around the central axis of the stationary shoulder by rotating the shaft ring. This adjusts the orientation of the support relative to the additive manufacturing part, so that during production, there is no need to adjust the orientation of the additive manufacturing part. The direction of movement of the entire friction stir additive manufacturing device can be changed while maintaining the orientation of the additive manufacturing part.

[0009] Furthermore, to facilitate the adjustment of the back pressure support structure's position on the hanger rod, thereby adjusting the distance between the support shaft and the stationary shoulder to accommodate substrates of different thicknesses and enable the formation of multiple additive layers, a stepless adjustment mechanism is provided below the back pressure support structure. This stepless adjustment mechanism includes a lead screw, a mandrel, and a tapered roller. The two ends of the lead screw are rotatably mounted on a hanger rod, and the lead screw includes a first threaded section and a second threaded section. The helical directions of the threads on the first threaded section and the second threaded section are opposite, and a mandrel is meshed on the first threaded section and the second threaded section, respectively. A tapered roller is rotatably mounted on each mandrel, with the small end of each tapered roller facing the other tapered roller. The tapered roller can rotate freely relative to its mandrel. The support roller includes a straight cylindrical section and tapered sections located at both ends of the straight cylindrical section. The large end of each tapered section faces the other tapered section, and each tapered roller is supported on a tapered section.

[0010] A limiting mechanism is provided on the suspension rod to restrict the spindle from rotating around its own central axis. When the lead screw rotates, it can drive the spindle to move towards or away from each other in the axial direction, and the spindle cannot rotate relative to its own central axis. When the spindle drives the conical roller to move back and forth in the axial direction, it can drive the back pressure support structure to move back and forth in the vertical direction.

[0011] Due to gravity, the tapered sections at both ends of the support roller press against the corresponding tapered rollers. When the screw is turned, when the two mandrels drive the tapered rollers to move towards each other, they push the support roller upwards. When the two mandrels drive the tapered rollers to move away from each other, the tapered rollers tend to move away from the support rollers. The support rollers, under the influence of gravity, move downwards to rest on the tapered rollers. This allows for smooth adjustment of the distance between the support rollers and the stationary shoulder. Because both the tapered sections of the tapered rollers and the support rollers are tapered, the height of the support rollers can be continuously and smoothly adjusted, forming stepless adjustment. This, in turn, allows for stepless adjustment of the distance between the support rollers and the stationary shoulder, accommodating the formation of additive layers of different thicknesses.

[0012] Specifically, the limiting mechanism includes a guide rod and a sliding member. Both ends of the guide rod are mounted on a suspension rod. For each mandrel, a sliding member is provided. One end of the sliding member is slidably mounted on the guide rod and can slide along the axial direction of the guide rod, while the other end is fixed to the corresponding mandrel. By utilizing the limiting effect of the sliding member, rotation of the mandrel around its central axis is prevented, while the reciprocating movement of the mandrel along the axial direction is not affected, ensuring the stepless adjustment mechanism can adjust the distance between the support roller and the stationary shoulder.

[0013] Furthermore, to improve the flexibility of the tapered roller rotating on the mandrel, the tapered roller is rotatably mounted on the mandrel via bearings.

[0014] Furthermore, to improve control flexibility, a drive motor is mounted on a boom, and the output shaft of this drive motor is connected to the lead screw. In actual production, this drive motor can also be integrated into an automatic control system to improve control over the lead screw rotation.

[0015] Specifically, to facilitate disassembly of the support unit, a pressure ring is fixed on the shaft ring. The upper end of the lifting rod passes freely from bottom to top through the lifting rod hole on the pressure ring and is then screwed with a lifting rod nut to connect the lifting rod to the pressure ring. When the workpiece being processed is annular, it is impossible to directly insert the workpiece substrate between the stirring shaft and the back pressure support structure, and it is also impossible to remove the stirring friction additive manufacturing device from the workpiece after processing. In this case, it is only necessary to unscrew the lifting rod nut from the lifting rod to separate the entire support unit from the additive manufacturing unit. After inserting the substrate between the support unit and the additive manufacturing unit, or after removing the workpiece, the lifting rod is then installed on the pressure ring via the lifting rod nut.

[0016] Furthermore, to facilitate control of the rotation of the support unit relative to the additive manufacturing unit, a steering mechanism is also included. This steering mechanism comprises a ring gear and a steering motor. The ring gear is fixedly mounted on the upper surface of the pressure ring, and the steering motor is mounted on the shoulder. The gear on the output shaft of the steering motor meshes with the ring gear. When it is necessary to adjust the direction of the support unit relative to the additive manufacturing unit, the steering motor can be used to drive the pressure ring to rotate relative to the shoulder, thereby adjusting the direction of the support unit relative to the additive manufacturing unit. This allows the entire friction stir additive manufacturing device to change its direction of movement while maintaining the orientation of the additive manufacturing unit during production, without needing to adjust the orientation of the additive manufacturing unit.

[0017] Furthermore, to ensure stable operation of the equipment, the stationary shoulder, stirring shaft, thrust ball bearing, and ring gear are coaxially arranged.

[0018] Furthermore, to facilitate the installation of the friction stir additive manufacturing device, a mounting portion is provided on the stationary shoulder, and a connecting portion is provided on the stirring shaft. The mounting portion is used to connect the stationary shoulder to the non-rotating part of the machining equipment, and the connecting portion is used to connect the stirring shaft to the rotating spindle rotor of the machining equipment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of this application.

[0020] Figure 2 for Figure 1 Enlarged view of part A in the middle.

[0021] Figure 3 for Figure 2 A view from the center (BB direction). Detailed Implementation

[0022] See Figures 1-3 A wire friction stir additive manufacturing device with back pressure support includes an additive part and a support part. The additive part includes a stationary shoulder 18 and a stirring shaft 20. The stationary shoulder 18 is cylindrical, giving it an inner cavity, and is coaxially arranged with the stirring shaft 20. The upper end of the stationary shoulder extends radially outward to form a flange 19, which serves as a mounting part for connecting the stationary shoulder to a non-rotating part of a machining equipment. A mounting hole 191 is provided on the flange 19.

[0023] The stirring shaft 20 includes, from bottom to top, a spiral rod 24, a transition section 23, and a drive shaft 22 connected sequentially. The spiral rod 24 specifically includes a vertically downward-extending rod body 241 and spiral blades 242 formed on the outer circumferential surface of the rod body. A downwardly protruding stirring needle 27 is present on the lower surface of the rod body 241, and the lower end face of the rod body forms the stirring shaft end face 251. The spiral rod 24 is inserted into the inner cavity of the stationary shaft shoulder, forming a spiral channel 243 between the spiral rod and the stationary shaft shoulder. A wire feeding hole 181 communicating with this spiral channel is provided on the stationary shaft shoulder.

[0024] A tangent plane 221 extending axially is provided on the side of the drive shaft 22. This tangent plane is used to be clamped onto the rotating spindle rotor of the machining equipment to drive the drive shaft to rotate, so that the drive shaft 22 also forms a connecting part.

[0025] During operation, the rotating spindle rotor of the machining equipment drives the stirring shaft to rotate, pressing the stirring needle into the substrate 81. The filament enters the spiral channel through the filament feeding hole 181, and then, driven by the spiral conveyor rod, the filament is squeezed, plasticized, and flows downwards, finally exiting the spiral channel. Under the pressure of the stirring shaft, it is then stirred and welded with the surface layer of the workpiece, continuously forming the additive layer 82 until the production of the workpiece 80 is complete. The lower end face 183 of the stationary shoulder 18 smooths the surface layer of the additively formed workpiece.

[0026] The support includes a thrust ball bearing 41, a load-bearing structure 40, and a back pressure support structure 50. A support ring 42 is fitted onto the stationary shoulder 18 and is bolted to the outer wall of the stationary shoulder. The thrust ball bearing 41 includes a housing ring 411, a shaft ring 412 located above the housing ring, and balls located between the housing ring and the shaft ring. The shaft ring is rotatably supported on the housing ring by the balls, and the housing ring 411 of the thrust ball bearing 41 is fixed to the upper side of the support ring 42.

[0027] The load-bearing structure 40 includes two opposing hanger rods 44 and a pressure ring 43. The pressure ring is fitted onto the stationary shaft shoulder and presses against the upper surface of the shaft ring 412 of the thrust ball bearing 41. Both hanger rods are mounted on the pressure ring. The hanger rods extend vertically and have a support flange 441 at their upper part. An external threaded section is provided on the hanger rod above the support flange. The external threaded section passes through the hanger rod hole 431 of the pressure ring 43 from bottom to top and is screwed with a hanger rod nut 442, thus suspending the hanger rod on the pressure ring 43 and detachably mounting the upper end of the hanger rod onto the shaft ring.

[0028] To ensure a stable connection with the thrust ball bearing 41, a lower groove is provided on the upper side of the support ring 42, and the seat ring 411 is tightly held in the lower groove. An upper groove is provided on the lower side of the pressure ring 43, and the shaft ring 412 is tightly held in the upper groove.

[0029] A back pressure support structure 50 is mounted on the bearing structure 40 and is located below the stirring shaft. The back pressure support structure 50 includes a support shaft 51 and a support roller 52. Both ends of the support shaft are connected to a suspension rod, and the support roller is rotatably mounted on the support shaft. Specifically, in this embodiment, to allow the support roller to rotate flexibly on the support shaft, both ends of the support roller are rotatably mounted on the support shaft via an angular contact bearing A53. A shoulder A is formed at both ends of the inner cavity of the support roller, and a locking nut A54 is screwed onto both ends of the support shaft. The locking nut A presses against the inner ring of the angular contact bearing A, and the outer ring of the angular contact bearing A presses against the shoulder step surface 523 of the shoulder A, allowing the support roller 52 to rotate freely and be held on the support shaft 51. The mounting method of the angular contact bearing A uses existing mature technology and will not be described in detail. It is understood that in another embodiment, the angular contact bearing A can be omitted, and the support roller 52 can be directly rotatably mounted on the support shaft.

[0030] To enable the back pressure support structure 50 to be adjusted according to the thickness of different workpieces and different thickness areas of the same workpiece, so as to maintain the contact between the support roller and the lower surface of the workpiece and provide support for the workpiece, a groove 443 is provided on each hanger rod. The groove 443 extends vertically and passes through the opposite sides of the hanger rod along the axial direction of the support shaft. The two ends of the support shaft are respectively formed as support ends 511, and each support end is inserted into the groove of a hanger rod. To prevent the support shaft from moving along its axial direction, an anti-movement nut 512 is screwed on each support end 511. The anti-movement nut is located on the outside of the hanger rod. The groove 443 allows the two ends of the support shaft to be slidably mounted on a hanger rod and to move back and forth in the vertical direction.

[0031] It is understood that, in another embodiment, a slide rail can be installed on the inner side of the boom, and corresponding sliders can be installed at both ends of the support shaft so that the sliders are held in place on the slide rail.

[0032] To facilitate the adjustment of the height of the back pressure support structure 50, thereby adjusting the distance between the support roller 52 and the stationary shoulder to accommodate processing areas of different workpiece thicknesses or substrates of different thicknesses, this embodiment also provides a stepless adjustment mechanism 60, which is located below the back pressure support structure.

[0033] The continuously variable adjustment mechanism 60 specifically includes a lead screw 61, a spindle 63, and a tapered roller 64. The two ends of the lead screw are each formed as an optical shaft 613, which are rotatably mounted on a suspension rod. The lead screw includes a first threaded section 611 and a second threaded section 612, with opposite helical directions. A spindle 63 meshes with each of the first and second threaded sections. A tapered roller 64 is rotatably mounted on each spindle 63, and the tapered roller can rotate freely relative to its corresponding spindle. The tapered roller is conical, with the small end of each tapered roller facing the other tapered roller. In this embodiment, the optical shaft is directly rotatably mounted in a corresponding shaft hole on the suspension rod. It can be understood that in another embodiment, the optical shaft can be mounted in the corresponding shaft hole via a bearing.

[0034] In this embodiment, each tapered roller is rotatably mounted on its corresponding mandrel via two angular contact bearings B65 and locked in place by lock nuts B66. The mounting method of the angular contact bearings B uses existing mature technology and will not be described in detail. It is understood that in another embodiment, the angular contact bearings B can be omitted, and the tapered roller can be directly rotatably fitted onto the mandrel.

[0035] The support roller 52 includes a straight cylindrical section 521 and tapered sections 522 located at both ends of the straight cylindrical section 521. The tapered sections are tapered, and the large end of each tapered section faces the other tapered section. Each tapered roller is supported on a tapered section.

[0036] During operation, the straight section 521 of the support roller 52 is supported on the lower surface of the workpiece 80, and each conical roller 64 is supported on a conical section 522. For clarity, in the attached drawings, there is a distance between the straight section 521 of the support roller 52 and the workpiece 80, and a distance between the conical roller 64 and the conical section 522.

[0037] To facilitate the driving of the lead screw, a drive motor 62 is installed on a boom, and the output shaft of the drive motor is connected to the lead screw.

[0038] To prevent the mandrel from rotating with the lead screw during its rotation, a limiting mechanism 70 is provided on the suspension rod. This limiting mechanism restricts the mandrel from rotating around its own central axis and is located below the continuously variable adjustment mechanism. The limiting mechanism 70 includes a guide rod 71 and a sliding member 72. Both ends of the guide rod are fixed to the suspension rod by a connecting bolt 73. A sliding member 72 is provided for each mandrel. Each sliding member 72 includes a sliding rod 722 and a connecting screw 723. A collar 721 is welded to one end of the sliding rod 722. This collar 721 freely fits onto the guide rod and can slide freely along the axial direction of the guide rod. The connecting screw 723 secures the other end of the sliding rod 722 to the end face of the corresponding mandrel 63.

[0039] Under the constraint of the limiting mechanism, when the lead screw rotates, it can drive the mandrel to move towards or away from each other in the axial direction, and the mandrel cannot rotate relative to its own central axis; when the mandrel drives the conical roller to move back and forth in the axial direction, it can drive the back pressure support structure to move back and forth in the vertical direction.

[0040] To facilitate rotation of the back pressure support structure and enable the additive manufacturing unit to change its direction of travel while maintaining its orientation, a steering mechanism is also provided in this embodiment. This steering mechanism includes an annular gear ring 46 and a steering motor 47. The annular gear ring 46 is fixedly mounted on the upper surface of the pressure ring 43, and the steering motor 47 is mounted on the outer wall of the stationary shoulder. A gear 48 on the output shaft of the steering motor meshes with the annular gear ring. The annular gear ring, thrust ball bearing, stirring shaft, and stationary shoulder are coaxially arranged.

[0041] In this application, both the drive motor 62 and the directional motor 47 are servo motors for precise control.

[0042] In this embodiment, during operation, the substrate 81 is first inserted between the stirring shaft and the back pressure support structure 50. Then, the drive motor 62 drives the lead screw to rotate, causing the two mandrels 63 to move the corresponding conical rollers 64 axially. This adjusts the height of the back pressure support structure 50, so that the support rollers 52 support the lower surface of the upwardly concave area of ​​the substrate, providing support for the downward pressure of the stirring needle and preventing the concave area from sinking downward under the pressure of the stirring needle. After the formation of one additive layer 82 is completed, the two mandrels 63 drive the corresponding conical rollers 64 to move axially in opposite directions, and the additive parts move upward synchronously until the distance between the stationary shoulder and the uppermost additive layer reaches the thickness of one additive layer. Then, the formation of the next additive layer continues, and this process is repeated until the production of the entire component is completed.

Claims

1. A wire friction stir additive manufacturing device with back pressure support, characterized by, The additive part includes a static shaft shoulder with an inner cavity and a stirring shaft including a screw rod and a driving shaft connected to the upper side of the screw rod, the screw rod is inserted into the inner cavity of the static shaft shoulder, a spiral channel is formed between the screw rod and the static shaft shoulder, and a wire feeding hole communicating with the spiral channel is formed on the static shaft shoulder; The support part includes a thrust ball bearing, a bearing structure and a back pressure support structure, the race of the thrust ball bearing is fixed on the static shaft shoulder, the bearing structure is detachably mounted on the shaft of the thrust ball bearing, and the back pressure support structure is mounted on the bearing structure and located below the stirring shaft; The bearing structure includes two oppositely arranged suspension rods, the suspension rods extend in the vertical direction, and the upper ends of the suspension rods are detachably mounted on the shaft of the thrust ball bearing; the back pressure support structure includes a support shaft and a support roller, the two ends of the support shaft are slidably mounted on a suspension rod and can reciprocate in the vertical direction, and the support roller is rotatably sleeved on the support shaft.

2. The wire friction stir additive manufacturing device of claim 1, wherein, A stepless adjusting mechanism is arranged below the back pressure support structure, the stepless adjusting mechanism includes a screw rod, a mandrel and a conical roller, the two ends of the screw rod are rotatably mounted on a suspension rod, the screw rod includes a first threaded section and a second threaded section, the screw threads on the first threaded section and the second threaded section have opposite helical directions, a mandrel is engaged on each of the first threaded section and the second threaded section, a conical roller is rotatably mounted on each mandrel, the small end of each conical roller faces the other conical roller, and the conical roller can freely rotate relative to the mandrel; the support roller includes a straight cylinder section and conical sections at the two ends of the straight cylinder section, the large end of each conical section faces the other conical section, and each conical roller is supported on a conical section; A limiting mechanism is arranged on the suspension rod, the limiting mechanism is used for limiting the mandrel from rotating around the central axis thereof, when the screw rod rotates, the mandrel can move towards or away from each other in the axial direction, and the mandrel cannot rotate relative to the central axis thereof; when the mandrel drives the conical roller to reciprocate in the axial direction, the back pressure support structure can reciprocate in the vertical direction.

3. The friction stir additive manufacturing device of claim 2, wherein, The limiting mechanism includes a light rod and a sliding piece, the two ends of the light rod are mounted on a suspension rod, and a sliding piece is arranged corresponding to each mandrel, one end of the sliding piece is slidably mounted on the light rod and can slide in the axial direction of the light rod, and the other end of the sliding piece is fixed on the corresponding mandrel.

4. The friction stir additive manufacturing device of claim 2, wherein, The conical roller is rotatably mounted on the mandrel through a bearing.

5. The friction stir additive manufacturing device of claim 2, wherein, A driving motor is mounted on a suspension rod, and the output shaft of the driving motor is connected to the screw rod.

6. The friction stir additive manufacturing device of claim 1, wherein, A pressing ring is fixed on the shaft, and the upper end of the suspension rod freely passes through a suspension rod hole on the pressing ring from bottom to top and is screwed with a suspension rod nut to connect the suspension rod to the pressing ring.

7. The friction stir additive manufacturing device of claim 1, wherein, A steering mechanism is further included, the steering mechanism includes an annular gear ring and a steering motor, the annular gear ring is fixedly installed on the upper surface of the pressing ring, and the steering motor is installed on the static shaft shoulder, and the gear on the output shaft of the steering motor is engaged with the annular gear ring.

8. The friction stir additive manufacturing device of claim 7, wherein, The static shaft shoulder, the stirring shaft, the thrust ball bearing and the annular gear ring are coaxially arranged.

9. The friction stir additive manufacturing device of claim 1, wherein, An installation part is arranged on the static shaft shoulder, and a connecting part is arranged on the stirring shaft.

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