A device and method for improving the uniformity of powder loading density of a tungsten rod

Abstract

The present application relates to the field of powder metallurgy forming technology, more particularly to a device and method for improving the uniformity of tungsten rod powder loading density, the device comprising: a rack; a spiral feeding mechanism installed on the rack for outputting powder; a composite vibration mechanism installed on the rack for driving the powder loading mold to generate a composite vibration field coupled in axial and radial directions; a lifting driving mechanism installed on the rack and connected with a moving platform for driving the moving platform to make vertical reciprocating motion relative to the powder loading mold; and a leveling mechanism installed on the moving platform for leveling the powder surface in the powder loading mold with the lifting of the moving platform. The synergistic effect of the composite ultrasonic vibration field structure, the stepped time delay shutdown timing and the ultrasonic frequency feedback dynamic correction can significantly improve the uniformity of the powder loading density.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy forming technology, specifically a device and method for improving the uniformity of powder loading density in tungsten rods. Background Technology

[0002] In the production process of refractory metal materials such as tungsten rods, the uniformity of powder density is the core factor that determines the mechanical properties and dimensional consistency of sintered products.

[0003] Traditional tungsten powder filling processes mainly rely on gravity-based natural filling or conventional mechanical vibration. Due to the high specific gravity, fine particle size, and easy oxidation of tungsten powder, traditional processes suffer from the following significant drawbacks: 1. The powder has poor flowability and is prone to bridging effect in the mold, resulting in discontinuous filling; 2. The mechanical vibration frequency is singular, making it difficult to break up powder agglomerates and easily generating significant axial and radial density gradients; 3. The lack of precise flow rate control during the filling process leads to severe quality fluctuations between different batches of products.

[0004] The aforementioned problems directly lead to uneven shrinkage, low density, local deformation, and even cracks in the sintered tungsten rods, severely limiting the yield of high-quality refractory metal products. Summary of the Invention

[0005] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To at least partially solve the above problems, in a first aspect, the present invention provides an apparatus for improving the uniformity of tungsten rod powder density, comprising: frame; The screw feed mechanism, mounted on the frame, is used to output powder; The composite vibration mechanism, mounted on the frame, is used to drive the powder filling mold to generate a composite vibration field with axial and radial coupling. The lifting drive mechanism is installed on the frame and connected to the mobile platform, and is used to drive the mobile platform to make vertical reciprocating motion relative to the powder filling mold; The leveling mechanism, installed on the mobile platform, is used to level the powder surface inside the powder filling mold as the mobile platform is raised and lowered. The control system is electrically connected to the screw feeding mechanism, the compound vibration mechanism, the lifting drive mechanism, and the leveling mechanism.

[0007] Furthermore, the control system is configured as follows: after the powder loading operation reaches the preset time, the screw feeding mechanism and the lifting drive mechanism are stopped, and the composite vibration mechanism and the leveling mechanism are shut down in sequence according to the stepped delay time sequence; wherein, before shutting down the composite vibration mechanism, the control system maintains the operation of the composite vibration mechanism for a preset first time to perform residual vibration compaction, and after shutting down the composite vibration mechanism, it maintains the operation of the leveling mechanism for a preset second time to perform post-leveling.

[0008] Furthermore, the composite vibration mechanism includes: An ultrasonic generator is electrically connected to the control system. The ultrasonic generator is connected to transducer A and transducer B via wires. The vibrating frame is elastically supported on the frame by a large spring sleeved on the frame support column. Transducer A is installed at the bottom of the vibrating frame to drive it to generate vertical vibration. The inner vibrating frame is located inside the outer vibrating frame and is penetrated by multiple support rods fixed to the outer vibrating frame. The inner vibrating frame is elastically mounted to the outer vibrating frame by small springs sleeved on the support rods and located on both sides of them. The transducer B is installed on the side of the inner vibrating frame to drive it to generate horizontal vibration. The powder filling mold is fixed on the inner vibrating frame, and the powder filling rubber sleeve is nested inside the powder filling mold.

[0009] Furthermore, the frame includes: a lower platform, multiple support columns vertically mounted on the lower platform, and an upper platform fixed to the top of the multiple support columns; the vibrating outer frame is supported on the steps of the support columns by a large spring and can perform elastic vibration in the vertical direction along the support columns.

[0010] Furthermore, the lifting drive mechanism includes: Motor A is installed on one side of the upper platform; The gear set includes gear A and gear B that mesh with each other. Gear A is connected to the output shaft of motor A, and gear B is mounted on the upper platform via bearing A. Nut C is fixedly nested at the center of gear B; A lead screw is vertically inserted into the upper platform and screwed to nut C. The lower end of the lead screw is fixed to one side of the moving platform. The guide rod, with its upper end fitted onto the upper platform and its lower end fixed to the other side of the moving platform, is used to radially limit the movement of the moving platform.

[0011] Furthermore, the leveling mechanism includes: Motor B is mounted on the side of the mobile platform; The chain drive assembly includes a gear C connected to the output end of a motor B via a key B, and a gear D connected to the gear C via a chain. A hollow tube is mounted on a mobile platform via bearing B and screwed to gear D. Its lower end extends into the powder filling mold and is connected to a scraper. The discharge end of the screw feeder extends into the hollow tube to transport the powder through the hollow tube to the powder filling mold.

[0012] Furthermore, the screw feeding mechanism includes: support plates, with two support plates fixed relative to each other on the upper platform; Motor C is mounted on the upper platform; Multiple helical shafts, including a helical shaft A that is connected to the motor C for transmission, and two helical shafts B symmetrically arranged on both sides of the helical shaft A. One end of both the helical shaft A and the helical shaft B is fixed with a meshing gear E. Both ends of each helical shaft are supported on two support plates by bearings C. The bearings C are axially fixed by bearing end caps installed on the support plates. The feeding hopper is installed on the upper platform and has multiple hoppers inside; the discharge ports of the multiple hoppers are aligned with the center of the screw shaft A and screw shaft B and are concentric with the multiple feed ports on the upper surface of the upper platform. The discharge seat is installed on the bottom surface of the upper platform. Multiple rubber tubes fixed on the discharge seat are screwed to the discharge ports of multiple hoppers; the lower ends of the multiple rubber tubes are inserted into multiple hollow tubes.

[0013] Secondly, the present invention provides a method for improving the uniformity of tungsten rod powder density, applied to the aforementioned device for improving the uniformity of tungsten rod powder density, the method comprising the following steps: S1. Inspect the equipment and complete the material preparation; S2. Set the rising speed V1 of the moving platform and the base speed V2 of the screw feed mechanism, monitor the ultrasonic frequency f in real time, and calculate the density correction coefficient K(f) according to the formula, K(f)=ρ 实际 / ρ 理论 , where ρ 理论 ρ is the theoretical density value of tungsten powder. 实际 This represents the actual powder density value at the current ultrasonic frequency f; S3. Dynamically adjust the actual feed rate V2' according to K(f), where V2' = V2 × K(f) × α, and α is the tungsten powder characteristic compensation coefficient, with a value range of 0.85-1.15, and ensure that V1 / V2' = πD 2 / 4, where D is the inner diameter of the powder-filling sleeve; S4. Start motors A, C, and B, as well as transducers A and B. Utilize the vertical vibration generated by transducer A and the horizontal vibration generated by transducer B to couple and form a three-dimensional composite ultrasonic field. Then, move the mobile platform upward at a rate of V1 to achieve layered filling and vibration composite operation. S5. When the powder loading time reaches T=L / V1, first turn off motors A and C, then turn off the ultrasonic generator after a first delay, and then turn off motor B after a second delay to complete the powder loading operation. Here, T is the powder loading time and L is the length of the powder loading sleeve.

[0014] Furthermore, in step S5, the first time is 2 seconds, which is used to utilize the residual vibration generated by the ultrasonic generator in conjunction with transducer A and transducer B to continue densifying the tungsten powder.

[0015] Furthermore, in step S5, the second time is 2 seconds, which is used to perform post-leveling by the leveling mechanism after the powder has stabilized, so that the amount of powder in each powder loading chamber is consistent.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This invention significantly improves the uniformity of powder density through the synergistic effect of a composite ultrasonic vibration field structure, a stepped delayed shutdown sequence, and dynamic correction based on ultrasonic frequency feedback. The vertical vibration generated by transducer A and the horizontal vibration generated by transducer B are coupled to form a three-dimensional composite ultrasonic vibration field. Vertical vibration promotes axial compaction, while horizontal vibration disrupts radial bridging and agglomeration, effectively suppressing the axial and radial segregation of high-density tungsten powder. This results in a significant reduction in axial and radial density deviations and a higher overall uniformity coefficient. The stepped delayed shutdown procedure maintains a 2-second residual vibration after feeding stops, utilizing the residual vibration energy to further densify the tungsten powder, filling micropores and effectively increasing the filling density. A 2-second static stabilization period eliminates the influence of the dynamic packing angle, ensuring the leveling mechanism levels the powder in a stable state and guaranteeing the consistency of powder content in each chamber. In addition, by introducing an ultrasonic frequency feedback density correction coefficient, the feeding speed is dynamically adjusted according to the real-time ultrasonic frequency, which effectively solves the problem of the impact of the fluctuation of physical properties of different batches of powder on the powder loading quality and ensures the real-time matching of powder flow and compaction rate during the layered powder filling process. Through precise control of filling and efficient compaction, the risk of deformation and cracking after sintering of tungsten rods is significantly reduced, and the performance consistency and yield of refractory metal products are improved.

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a first-view schematic diagram of the device for improving the uniformity of tungsten rod powder density according to the present invention. Figure 2 This is a second-view schematic diagram of the device for improving the uniformity of tungsten rod powder density according to the present invention; Figure 3 This is a partial schematic diagram of the device for improving the uniformity of tungsten rod powder density according to the present invention; Figure 4This is a schematic diagram of the hollow tube and the scraper blade of the present invention; Figure 5 This is a side view of the device for improving the uniformity of tungsten rod powder density according to the present invention; Figure 6 for Figure 5 A partial sectional view at point AA in the middle; Figure 7 This is a comparison chart of experimental data on the uniformity of tungsten powder density during synchronous shutdown and stepped delayed shutdown in this invention. Figure 8 This is a comparison chart of experimental data on the axial density distribution of tungsten powder during synchronous shutdown and stepped delayed shutdown in this invention; Figure 9 This is a graph showing the relationship between ultrasonic frequency and powder density in this invention.

[0019] Icons: 101. Lower platform; 102. Support column; 103. Upper platform; 104. Nut A; 201. Ultrasonic generator; 202. Wire; 203. Transducer A; 204. Transducer B; 205. Vibrating outer frame; 206. Large spring; 207. Vibrating inner frame; 208. Small spring; 209. Support rod; 211. Powder filling sleeve; 212. Powder filling mold; 213. Bolt; 301. Motor A; 302. Gear A; 303. Key A; 304. Gear B; 305. Bearing A; 306. Nut C; 307. Lead screw; 308. Moving platform; 309. Guide rod; 401. Motor B; 402. Gear C; 403. Chain; 404. Key B; 405. Gear D; 406. Bearing B; 407. Hollow tube; 408. Scraper blade; 501. Support plate; 502. Bearing end cover; 503. Bearing C; 504. Screw shaft A; 505. Screw shaft B; 506. Gear E; 507. Feeding bin; 508. Discharge seat; 509. Rubber material tube; 510. Motor C; 511. Key C; 601. Controller.

[0020] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The following is in conjunction with the appendix Figure 1 -Appendix Figure 9 The present invention will be described in further detail below.

[0023] Example 1: like Figure 1 As shown, a device for improving the uniformity of tungsten rod powder density includes: frame; The screw feed mechanism, mounted on the frame, is used to output powder; The composite vibration mechanism, mounted on the frame, is used to drive the powder filling mold 212 to generate a composite vibration field with axial and radial coupling. The lifting drive mechanism is installed on the frame and connected to the mobile platform 308, and is used to drive the mobile platform 308 to perform vertical reciprocating motion relative to the powder filling mold 212. A leveling mechanism is installed on the mobile platform 308 and is used to level the powder surface inside the powder filling mold 212 as the mobile platform 308 is raised and lowered. The control system is electrically connected to the screw feeding mechanism, the compound vibration mechanism, the lifting drive mechanism, and the leveling mechanism. The control system is configured to stop the screw feeding mechanism and the lifting drive mechanism after the powder loading operation reaches a preset time T, and sequentially shut down the compound vibration mechanism and the leveling mechanism according to the stepped delay sequence. Before shutting down the compound vibration mechanism, the control system maintains the compound vibration mechanism in operation for a preset first time to perform residual vibration compaction, and after shutting down the compound vibration mechanism, maintains the leveling mechanism in operation for a preset second time to perform post-leveling.

[0024] This invention discloses a device for improving the uniformity of tungsten rod powder density. Through the precise spatial layout of the hardware mechanism and the specific timing logic of the control system, it achieves uniform filling of high-density powder. In this invention, a spiral feeding mechanism is used to quantitatively output powder, while a lifting drive mechanism drives a moving platform 308 to perform vertical reciprocating motion relative to the powder filling mold 212, realizing the layer-by-layer stacking and filling of powder within the powder filling mold 212. A composite vibration mechanism causes the powder filling mold 212 to generate wave field coupling in the axial and radial directions, forming a three-dimensional composite ultrasonic vibration field, thereby breaking up powder agglomeration in real time during the filling process. A leveling mechanism is installed on the moving platform 308 and, as the moving platform 308 rises and falls, scrapes the powder surface within the powder filling mold 212 in real time to ensure the consistency of the powder filling height.

[0025] The control system of this invention employs a stepped delayed shutdown logic. After a preset time is reached, the control system executes a specific timing sequence: Phase 1: First, shut down the feeding and lifting movements.

[0026] The second stage (residual vibration densification): the composite vibration mechanism is shut down immediately after a delay, and the residual ultrasonic energy is used to further settle and densify the powder that is in a static accumulation state.

[0027] The third stage (post-leveling): The leveling mechanism is shut off after a second delay to ensure that the final surface leveling is completed after the powder is completely stable and the dynamic accumulation angle is eliminated.

[0028] This invention can significantly improve the uniformity of powder density. By coupling vertical and horizontal vibrations, it effectively suppresses the axial and radial bidirectional segregation of high-density tungsten powder during the filling process. This invention can also eliminate shutdown disturbances and achieve secondary densification. By executing a stepped delayed shutdown procedure, the residual vibration energy in the first time allows the tungsten powder to continue filling the micropores, effectively improving the final filling density. Through steady-state leveling in the second time, the influence of dynamic repose angle on the surface is eliminated, ensuring the consistency of powder content in each cavity. Finally, through precise control of filling and efficient compaction, the risk of deformation and cracking of tungsten rods in the subsequent sintering process is significantly reduced, improving the performance consistency and yield of high-density tungsten products.

[0029] Example 2: like Figure 1 and Figure 3 As shown, in a device for improving the uniformity of tungsten rod powder density according to the present invention, the composite vibration mechanism includes: An ultrasonic generator 201 is electrically connected to the control system. The ultrasonic generator 201 is connected to transducers A203 and B204 via wires 202. The vibration frame 205 is elastically supported on the frame by a large spring 206 sleeved on the frame support column 102. The transducer A203 is installed at the bottom of the vibration frame 205 to drive it to generate vertical vibration. The inner vibrating frame 207 is disposed within the outer vibrating frame 205 and is penetrated by multiple support rods 209 fixed to the outer vibrating frame 205. The inner vibrating frame 207 is elastically mounted to the outer vibrating frame 205 by small springs 208 sleeved on the support rods 209 and located on both sides thereof. The transducer B204 is mounted on the side of the inner vibrating frame 207 to drive it to generate horizontal vibration, thereby forming a composite ultrasonic vibration field. The powder filling mold 212 is fixed on the inner vibrating frame 207. The powder filling mold 212 is fixed on the inner vibrating frame 207 by bolts 213 and nuts B. The powder filling sleeve 211 is nested inside the powder filling mold 212.

[0030] The composite vibration mechanism of this invention achieves a three-dimensional composite vibration field through nested inner and outer frames and bidirectional dynamic decoupling. Regarding vertical vibration transmission: the control system drives the ultrasonic generator 201 via wire 202. The ultrasonic generator 201 is connected to transducers A203 and B204 via wire 202. Transducer A203 is installed at the bottom of the vibration outer frame 205. Since the vibration outer frame 205 is elastically supported on the frame support column 102 by a large spring 206, the energy excited by transducer A203 causes the entire vibration outer frame 205 to generate high-frequency vertical vibration. Regarding horizontal vibration... Conduction: Transducer B204 is installed on the side of the inner vibrating frame 207. The inner vibrating frame 207 is suspended by a small spring 208 on a support rod 209 fixed to the outer vibrating frame 205. This elastic installation method allows the inner vibrating frame 207 to generate high-frequency reciprocating motion in the horizontal direction. Finally, the vibrations in the vertical and horizontal dimensions converge and couple at the inner vibrating frame 207 to form a composite ultrasonic vibration field. The powder filling mold 212 is rigidly fixed to the inner vibrating frame 207 by bolts 213 and nuts B, ensuring that the vibration energy is transmitted to the powder filling sleeve 211 and the powder inside the powder filling mold 212 without loss.

[0031] This invention achieves mechanical decoupling of vertical and horizontal vibrations in space by driving the outer vibration frame 205 and the inner vibration frame 207 with transducers A203 and B204 respectively. This composite vibration field effectively breaks the agglomeration bridging between high-density tungsten powders and suppresses axial and radial bidirectional segregation of powders during the filling process. Compared with single vibration, the structure in this embodiment reduces the axial density deviation to 1.2% and the radial density deviation to 0.8%. This invention employs a dual buffer system of large spring 206 and small spring 208, which greatly attenuates the destructive vibration transmitted to the frame while ensuring that the mold receives high-frequency energy, thus reducing the mechanical fatigue of the equipment. In addition, this invention solves the energy loss problem caused by the jumping of the powder filling mold 212 in traditional filling by using the rigid connection of bolt 213 and nut B, ensuring the stability of the tapped density. Through the precise tapping of the composite vibration mechanism in this embodiment, the density distribution of tungsten rods after sintering can be significantly improved, reducing the risk of deformation or cracking caused by density gradients and ensuring the consistency of the final product.

[0032] Example 3: like Figure 1 , Figure 3 , Figure 5 and Figure 6As shown, in a device for improving the uniformity of tungsten rod powder density according to the present invention, the frame includes: a lower platform 101, multiple support columns 102 vertically installed on the lower platform 101, and an upper platform 103 fixed to the top of the multiple support columns 102; the lower platform 101 is screwed to the lower end of the support columns 102; the upper end of the support columns 102 is fixed to the upper platform 103 by nuts A104; the vibrating outer frame 205 is supported on the step of the support columns 102 by a large spring 206, and can perform elastic vibration in the vertical direction along the support columns 102. The lifting drive mechanism includes: a motor A301, mounted on one side of the upper platform 103; a gear set including meshing gears A302 and B304, with gear A302 connected to the output shaft of motor A301 and gear B304 mounted on the upper platform 103 via bearing A305; wherein, motor A301 is connected to gear A302 via key A303; a nut C306, fixedly nested in the center of gear B304; a lead screw 307, vertically inserted through the upper platform 103 and screwed to the nut C306, with the lower end of the lead screw 307 fixed to one side of the moving platform 308; and a guide rod 309, with its upper end sleeved on the upper platform 103 and its lower end fixed to the other side of the moving platform 308, used for radially limiting the moving platform 308.

[0033] In a device for improving the uniformity of tungsten rod powder loading density according to the present invention, the frame is formed by a lower platform 101, a support column 102, and an upper platform 103 to form a cage-like rigid frame. The lower end of the support column 102 is screwed to the lower platform 101 at the bottom, and the upper end passes through the upper platform 103 and is locked by a nut A104, providing a stable physical reference for the entire powder loading system. The support column 102 has a dual function: it not only serves as a load-bearing support for the frame, but also supports a large spring 206 through a step on it, enabling the vibrating outer frame 205 to perform elastic vibration in the vertical direction guided by the support column 102. The motor A301 outputs torque, which drives the gear A30 through the key A303. 2. The rotation drives the meshing gear B304 and the nut C306 nested therein to rotate in place. Since the nut C306 is screwed to the vertically inserted lead screw 307, and the lower end of the lead screw 307 is fixed to the moving platform 308, the rotation of the nut C306 is converted into the vertical linear motion of the moving platform 308. The guide rod 309 is set parallel to the lead screw 307, with its upper end sleeved on the upper platform 103 and its lower end fixed to the other side of the moving platform 308. During the lifting process, the guide rod 309 counteracts the reverse torque generated by the transmission of the lead screw 307, ensuring that the moving platform 308 can only run smoothly in the vertical direction and preventing radial deviation.

[0034] In this invention, the vibration outer frame 205 is suspended on the middle step of the support column 102, while the lifting drive mechanism is installed on the top of the frame, making the high-frequency vibration field and the precision displacement field relatively independent in space and in the force chain, avoiding the interference of ultrasonic vibration on the precision of the lifting motor and gears; in addition, the cage structure of multiple support columns 102 connecting the upper and lower platforms greatly enhances the overall rigidity of the device. When filling with high-density tungsten powder, the frame can effectively absorb the impact force generated by the composite vibration field, ensuring the stability of the equipment under high load.

[0035] Example 4: like Figure 1 , Figure 3 , Figure 4 As shown, in a device for improving the uniformity of tungsten rod powder density according to the present invention, the leveling mechanism includes: a motor B401, installed on the side of the moving platform 308; a chain drive assembly, including a gear C402 connected to the output end of the motor B401 via a key B404, and a gear D405 connected to the gear C402 via a chain 403; a hollow tube 407, installed on the moving platform 308 via a bearing B406 and screwed to the gear D405, the lower end of which extends into the powder filling mold 212 and is connected to a scraper 408; and the discharge end of the screw feeding mechanism extends into the hollow tube 407 to convey the powder to the powder filling mold 212 via the hollow tube 407.

[0036] In a device for improving the uniformity of tungsten rod powder density according to the present invention, a motor B401 is installed on the side of a moving platform 308, and its output end is connected to a gear C402 via a key B404. The gear C402 is connected to a gear D405 via a chain 403 to transmit the motor power to the execution end. The gear D405 is installed on the moving platform 308 via a bearing B406 and is screwed to a hollow tube 407. Driven by the chain 403, the gear D405 drives the hollow tube 407 and the scraper 408 connected to its lower end to rotate around the axis. The leveling mechanism adopts a spatial nested layout. The discharge end of the spiral feeding mechanism extends into the interior of the hollow tube 407. During the conveying process, the powder falls into the powder filling mold 212 through the internal diameter of the hollow tube 407. The leveling mechanism as a whole moves vertically back and forth with the moving platform 308. While the powder is falling, the rotating scraper 408 levels the powder surface in the powder filling mold 212 in real time.

[0037] This invention effectively solves the structural interference problem of simultaneously conveying powder and rotating leveling within a narrow mold diameter by extending the discharge end of the spiral feeding mechanism into the hollow tube 407 through a nested design. The rotating leveling blade 408 effectively breaks the dynamic accumulation angle formed by powder accumulation, ensuring a consistent powder surface height. Combined with the layered powder filling process, it significantly reduces axial and radial density deviations. The chain drive assembly used in this invention not only provides smooth transmission but also facilitates the simultaneous driving of multiple gears D405 by a single chain 403, ensuring a high degree of synchronization and consistency in leveling actions during multi-station powder filling operations. Furthermore, this mechanism rises and falls with the moving platform 308, enabling continuous operation during the dynamic powder filling process. Combined with the timing control of the control system, it ensures the consistency of powder filling amount in each cavity.

[0038] Example 5: like Figures 1-6 As shown, in a device for improving the uniformity of tungsten rod powder density according to the present invention, the spiral feeding mechanism includes: a support plate 501, two support plates 501 fixed relative to each other on an upper platform 103; a motor C510, mounted on the upper platform 103; and multiple spiral shafts, including a spiral shaft A504 connected to the motor C510 and two spiral shafts B505 symmetrically arranged on both sides of the spiral shaft A504. A gear E506 is fixed to one end of both spiral shaft A504 and spiral shaft B505, and the two meshing gears E506 are respectively mounted on spiral shaft A504 and spiral shaft B505 via a key C511; each spiral shaft has two ends... All are supported on two support plates 501 by bearings C503, and bearings C503 are axially fixed by bearing end caps 502 installed on support plates 501; the discharge bin 507 is installed on the upper platform 103 and has multiple bins inside; the discharge ports of the multiple bins are aligned with the center of the screw shafts A504 and B505 and are concentric with the multiple inlets on the upper surface of the upper platform 103; the discharge seat 508 is installed on the bottom surface of the upper platform 103, and multiple rubber tubes 509 fixed on the discharge seat 508 are screwed to the discharge ports of the multiple bins; the lower ends of the multiple rubber tubes 509 are inserted into multiple hollow tubes 407.

[0039] In a device for improving the uniformity of tungsten rod powder density according to the present invention, a motor C510 is installed on the upper platform 103 as a power source, and its output end is connected to the spiral shaft A504 for transmission. At one end of the spiral shaft A504 and one end of the two symmetrically arranged spiral shafts B505, gears E506 are installed through a key C511. The motor C510 drives the spiral shaft A504 to rotate, and transmits power synchronously to the two spiral shafts B505 through the meshing of the gears E506. Both ends of the spiral shaft A504 and the two spiral shafts B505 are supported by bearings C503 on two relatively fixed support plates 501. The bearing C503 is axially fixed to the upper platform 103 by the bearing end cap 502, ensuring the stability of the shaft system under high-speed rotation. The feeding hopper 507 is installed on the upper platform 103, with multiple hopper outlets aligned with the centers of the spiral shafts A504 and B505, ensuring material falls into the spiral groove. These hopper outlets are concentric with the feed inlet on the upper surface of the upper platform 103, forming a vertically continuous path. The discharge seat 508 is installed on the bottom surface of the upper platform 103, with multiple rubber tubes 509 whose upper ends are screwed to the outlets of the multiple hoppers, and whose lower ends are inserted into multiple hollow tubes 407. The thrust generated by the rotating spiral shaft quantitatively and continuously presses tungsten powder into the rubber tubes 509, ultimately conveying it to the subsequent powder loading stage.

[0040] This invention utilizes the coordinated design of motor C510, gear E506, and spiral shafts A504 and B505 to achieve synchronous rotation of multiple spiral shafts under a single power drive. This ensures that multiple powder-filling cavities receive a highly consistent feed flow rate within the same timeframe, resolving the uniformity deviation problem in mass production. The concentric arrangement of the hopper outlet, spiral shaft center, and upper platform inlet minimizes material flow resistance, preventing bridging or accumulation of tungsten powder in conveying blind spots and ensuring the continuity of the powder-filling process. The invention employs a rubber tube 509 as the connection medium between the output and execution ends. This not only establishes physical connectivity but also utilizes the flexibility of rubber to dampen vibrations, isolating energy transfer between the spiral feeding mechanism and the subsequent composite vibration mechanism. This protects the precision of the gear set's fit and ensures that the rubber tube 509 does not obstruct vibrations generated by the composite vibration mechanism.

[0041] Example 6: like Figures 1-3 , Figures 7-9 As shown, in a device for improving the uniformity of tungsten rod powder density according to the present invention, a method for improving the uniformity of tungsten rod powder density is applied to the device, and the method includes the following steps: S1. Inspect the equipment and complete the material preparation; S2. Set the rising speed V1 of the moving platform 308 and the base speed V2 of the screw feeding mechanism, monitor the ultrasonic frequency f in real time, and calculate the density correction coefficient K(f) according to the formula, K(f) = ρ 实际 / ρ 理论 , where ρ 理论 ρ is the theoretical density value of tungsten powder. 实际 This represents the actual powder density value at the current ultrasonic frequency f; In this invention, the actual powder loading density value ρ at the current ultrasonic frequency f is... 实际 The specific calculation method is as follows: First, a laser displacement sensor installed above the powder filling sleeve 211 is used to detect the height H of the powder surface inside the powder filling mold 212 in real time at a preset sampling period. Combined with the inner diameter of the powder filling sleeve 211, the real-time filling volume V at the corresponding time node is calculated, where V = ¼πD. 2 ×H; Simultaneously, the control system synchronously collects the real-time feedback speed signal of the screw feed mechanism within the same sampling period, converts the speed signal into the total number of screw shaft revolutions within the sampling period, and multiplies it by the pre-calibrated single-revolution feed constant to convert it into the cumulative feed mass M within the period; the single-revolution feed constant is a value obtained by pre-weighing and calibrating tungsten powder of a specific particle size under standard conditions; Finally, the control system calculates the ratio of the cumulative feed mass M to the real-time filling volume V in each sampling period with the time axis aligned, thereby generating the actual powder density value that reflects the powder compactness at the current ultrasonic frequency in real time. This method can provide feedback on the ultrasonic vibration effect through direct measurement of physical parameters and clock synchronization calculation; S3. Dynamically adjust the actual feed rate V2' according to K(f), where V2' = V2 × K(f) × α, and α is the tungsten powder characteristic compensation coefficient, with a value range of 0.85-1.15, and ensure that V1 / V2' = πD 2 / 4, where D is the inner diameter of the powder-filling sleeve 211; S4. Start motors A301, C510, and B401, as well as transducers A203 and B204. Utilize the vertical vibration generated by transducer A203 and the horizontal vibration generated by transducer B204 to couple and form a three-dimensional composite ultrasonic field. This causes the moving platform 308 to move upwards at a rate of V1 to achieve layered filling and vibration composite operation. The control system includes a controller 601, which is connected to the ultrasonic generator 201, motors A301, B401, and C510 via wires 202. S5. When the powder loading time reaches T=L / V1, first turn off motors A301 and C510, then turn off ultrasonic generator 201 after a first delay, and then turn off motor B401 after a second delay, completing the powder loading operation. Here, T is the powder loading time, and L is the length of the powder loading sleeve. The first delay is 2 seconds, used to utilize the residual vibration generated by ultrasonic generator 201 in conjunction with transducers A203 and B204 to continue densifying the tungsten powder. The second delay is 2 seconds, used for post-leveling by the leveling mechanism after the powder has stabilized, ensuring consistent powder quantity in each loading chamber.

[0042] To verify the effect of the composite ultrasonic vibration field described in this invention on the uniformity of tungsten powder loading, a comparative experiment was conducted to verify the mechanism of action of the composite ultrasonic vibration field. Three sets of conditions were set up for the experiment: (1) Control group 1: No ultrasonic vibration; (2) Control group 2: only vertical ultrasonic vibration (or a single vibration mode of transducer A203 or transducer B204). (3) Experimental group: the composite ultrasonic field of the present invention (vertical + horizontal bidirectional).

[0043] The experimental results are shown in the table below: Experimental results show that, compared with single-direction vibration, the composite ultrasonic vibration field of the present invention reduces the axial density deviation by 82.4%, the radial density deviation by 85.5%, and the overall uniformity coefficient by 11.4%, proving that the coupling effect of vertical and horizontal vibration can effectively solve the problem of "radial and axial bidirectional segregation" in the filling process of tungsten powder, a high-density powder.

[0044] This invention employs a dynamic correction control process based on ultrasonic frequency feedback to address the impact of fluctuations in the physical properties of different batches of powder on powder loading quality, ensuring real-time matching between powder flow and compaction rate during layered powder filling. The dynamic correction process includes the following key nodes: 1. Real-time monitoring and acquisition: The control system monitors the ultrasonic frequency f during the operation of the composite vibration mechanism in real time.

[0045] 2. Coefficient calculation: The system automatically calculates the current density correction factor K(f) based on the monitored frequency f.

[0046] 3. Target density comparison: Compare the calculated actual powder density with the target preset density.

[0047] 4. Multi-parameter coordinated adjustment.

[0048] Adjust the feed rate: Calculate the new V2' according to the correction formula, and then adjust the running speed of the screw feeder.

[0049] Adjusting the lifting speed: While adjusting the feeding speed, it is necessary to ensure that V1 / V2'=πD is satisfied. 2 The ratio is 4 / D (where D is the inner diameter of the powder-filling sleeve). If necessary, the lifting speed V1 of the moving platform needs to be increased or adjusted.

[0050] The mechanism is as follows: the vertical vibration driven by transducer A203 mainly promotes the axial compaction and layered filling of the powder, while the horizontal vibration driven by transducer B204 disrupts the radially formed arch structure and agglomerates of the powder. The elastic buffering effect of the large spring 206 and the small spring 208 decouples the vibrations in the two directions, avoids the mutual cancellation of vibration energy, and enables the two vibration modes to form a synergistic three-dimensional composite vibration field within the powder filling mold 212.

[0051] Verification of the effect of the stepped delayed shutdown sequence: To verify the technical effectiveness of the stepped delayed shutdown sequence (S5 step), a comparative experiment was conducted between synchronous shutdown and stepped delayed shutdown. Experimental conditions: powder-filled sleeve specifications Φ60×1000mm, tungsten powder particle size -200 mesh.

[0052] like Figure 7 and Figure 8 As shown, the results indicate that: 1. Synchronous shutdown mode (conventional control mode): Due to the large stacking angle of tungsten powder (about 35-40°), sudden stopping of vibration will cause unstable accumulation on the powder surface. Immediately scraping it flat will disturb the powder distribution, resulting in a "hump" distribution with higher density at the top and lower density in the middle, with an axial density deviation of up to 8.5%.

[0053] 2. Stepped delay shutdown (control method of this invention): Stage I (T~T+2s, residual vibration densification period): After stopping feeding and lifting, maintain ultrasonic vibration for 2 seconds to use residual vibration energy to continue densifying the powder, filling micropores, and effectively increasing density; Figure 8 This is a comparison chart of experimental data on the axial density distribution of tungsten powder during synchronous shutdown and stepped delayed shutdown according to the present invention. The present invention verifies the influence of different shutdown schemes on the powder density and axial uniformity of tungsten rods through comparative experiments. The experiment is divided into two modes: synchronous shutdown and stepped delayed shutdown, and density sampling is performed at five positions: top, upper, middle, lower and bottom of the tungsten rod.

[0054] According to measurement data, the average powder loading density along the entire axis was 17.22 g / cm³ under the synchronous shutdown scheme, while the average powder loading density along the entire axis increased to 17.42 g / cm³ after adopting the stepped delayed shutdown scheme, with the overall absolute density increasing by 0.20 g / cm³. 3 The increase was approximately 1.16%.

[0055] Analysis of distribution consistency revealed a significant density collapse in the central region (only 16.5 g / cm³) in the synchronous shutdown scheme, while the stepped delayed shutdown scheme, through timing optimization, significantly compensated for the central density to 17.3 g / cm³. 3 The single-point improvement was as high as 4.8%.

[0056] The results show that the stepped delayed shutdown scheme not only effectively improves the overall powder loading density, but more importantly, it greatly reduces the density difference between points along the axis, making the overall density distribution of the tungsten rod more stable and consistent, which is significantly better than the traditional synchronous shutdown scheme.

[0057] Figure 7 This is a comparison chart of experimental data on the uniformity of tungsten powder density under synchronous shutdown and stepped delayed shutdown according to the present invention. The chart shows that under the synchronous shutdown scheme, the axial density deviation is 8.5%, the radial density deviation is 6.2%, and the overall uniformity coefficient is only 85.3%. This indicates that the traditional synchronous shutdown mode cannot compensate for the spatiotemporal lag effect of powder filling, resulting in significant density fluctuations in the tungsten rod in both the length and cross-sectional directions. In contrast, after adopting the stepped delayed shutdown scheme of the present invention, all indicators are comprehensively optimized: the axial density deviation drops sharply from 8.5% to 1.2%, the radial density deviation drops from 6.2% to only 0.8%, and the overall uniformity coefficient significantly increases from 85.3% to approximately 98.5%. Experimental results demonstrate that the stepped delayed shutdown scheme, through precise control of the shutdown sequence, reduces the deviation index by 5.4% to 7.3% and improves the overall uniformity by more than 13.2%. This scheme effectively eliminates the density inconsistency during the powder loading process, improving the axial and radial consistency of the tungsten rod by an order of magnitude, and providing excellent initial blank guarantee for subsequent high-quality sintering.

[0058] Phase II (T+2s~T+4s, post-leveling period): After the ultrasonic treatment stops, wait for 2 seconds to allow the powder to stabilize completely and eliminate the influence of the dynamic stacking angle. At this time, leveling will not disturb the internal structure of the powder. The final axial density deviation was reduced to 1.2%, an improvement of 85.9% compared to synchronous shutdown.

[0059] The specific time interval of 2 seconds + 2 seconds was optimized for the high density (19.25 g / cm³) and large angle of repose characteristics of tungsten powder. If the time is too short (<1 second), sufficient densification cannot be achieved, while if the time is too long (3 seconds), production efficiency will be reduced and powder rebound may occur due to vibration attenuation.

[0060] Figure 9 This is a graph showing the relationship between ultrasonic frequency and powder density in this invention. The green area represents the optimal frequency range, and the blue curve represents the actual powder density. Figure 9It can be seen that the actual powder density is higher in the optimal frequency range of 28-32kHz.

[0061] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A device for improving the uniformity of powder density in tungsten rods, characterized in that, include: frame; The screw feed mechanism, mounted on the frame, is used to output powder; The composite vibration mechanism, mounted on the frame, is used to drive the powder filling mold to generate a composite vibration field with axial and radial coupling. The lifting drive mechanism is installed on the frame and connected to the mobile platform, and is used to drive the mobile platform to make vertical reciprocating motion relative to the powder filling mold; The leveling mechanism, installed on the mobile platform, is used to level the powder surface inside the powder filling mold as the mobile platform is raised and lowered. The control system is electrically connected to the screw feeding mechanism, the compound vibration mechanism, the lifting drive mechanism, and the leveling mechanism.

2. The device for improving the uniformity of tungsten rod powder density according to claim 1, characterized in that, The control system is configured as follows: after the powder loading operation reaches the preset time, the control system stops the operation of the screw feeding mechanism and the lifting drive mechanism, and shuts down the composite vibration mechanism and the leveling mechanism in sequence according to the stepped delay time sequence; before shutting down the composite vibration mechanism, the control system maintains the operation of the composite vibration mechanism for a preset first time to perform residual vibration compaction, and after shutting down the composite vibration mechanism, it maintains the operation of the leveling mechanism for a preset second time to perform post-leveling.

3. The device for improving the uniformity of tungsten rod powder density according to claim 1, characterized in that, The composite vibration mechanism includes: An ultrasonic generator is electrically connected to the control system. The ultrasonic generator is connected to transducer A and transducer B via wires. The vibrating frame is elastically supported on the frame by a large spring sleeved on the frame support column. Transducer A is installed at the bottom of the vibrating frame to drive it to generate vertical vibration. The inner vibrating frame is located inside the outer vibrating frame and is pierced by multiple support rods fixed to the outer vibrating frame. The inner vibrating frame is elastically mounted to the outer vibrating frame by small springs sleeved on the support rods and located on both sides of them. The transducer B is installed on the side of the inner vibrating frame to drive it to generate horizontal vibration. The powder filling mold is fixed on the inner vibrating frame, and the powder filling rubber sleeve is nested inside the powder filling mold.

4. The device for improving the uniformity of tungsten rod powder density according to claim 3, characterized in that, The rack includes: The system includes a lower platform, multiple support columns vertically installed on the lower platform, and an upper platform fixed to the top of the multiple support columns. The vibrating outer frame is supported on the steps of the support columns by a large spring and can perform elastic vibration in the vertical direction along the support columns.

5. The device for improving the uniformity of tungsten rod powder density according to claim 4, characterized in that, The lifting drive mechanism includes: Motor A is installed on one side of the upper platform; The gear set includes gear A and gear B that mesh with each other. Gear A is connected to the output shaft of motor A, and gear B is mounted on the upper platform via bearing A. Nut C is fixedly nested at the center of gear B; A lead screw is vertically inserted into the upper platform and screwed to nut C. The lower end of the lead screw is fixed to one side of the moving platform. The guide rod, with its upper end fitted onto the upper platform and its lower end fixed to the other side of the moving platform, is used to radially limit the movement of the moving platform.

6. The device for improving the uniformity of tungsten rod powder density according to claim 5, characterized in that, The leveling mechanism includes: Motor B is mounted on the side of the mobile platform; The chain drive assembly includes a gear C connected to the output end of a motor B via a key B, and a gear D connected to the gear C via a chain. A hollow tube is mounted on a mobile platform via bearing B and screwed to gear D. Its lower end extends into the powder filling mold and is connected to a scraper. The discharge end of the screw feeder extends into the hollow tube to transport the powder through the hollow tube to the powder filling mold.

7. The device for improving the uniformity of tungsten rod powder density according to claim 6, characterized in that, The screw feeding mechanism includes: support plates, two support plates fixed relative to each other on the upper platform; Motor C is mounted on the upper platform; Multiple helical shafts, including a helical shaft A that is connected to the motor C for transmission, and two helical shafts B symmetrically arranged on both sides of the helical shaft A. One end of both the helical shaft A and the helical shaft B is fixed with a meshing gear E. Both ends of each helical shaft are supported on two support plates by bearings C. The bearings C are axially fixed by bearing end caps installed on the support plates. The feeding hopper is installed on the upper platform and has multiple hoppers inside; the discharge ports of the multiple hoppers are aligned with the center of the screw shaft A and screw shaft B and are concentric with the multiple feed ports on the upper surface of the upper platform. The discharge seat is installed on the bottom surface of the upper platform. Multiple rubber tubes fixed on the discharge seat are screwed to the discharge ports of multiple hoppers; the lower ends of the multiple rubber tubes are inserted into multiple hollow tubes.

8. A method for improving the uniformity of tungsten rod powder density, applied to the device for improving the uniformity of tungsten rod powder density as described in claim 7, characterized in that, The method includes the following steps: S1. Inspect the equipment and complete the material preparation; S2. Set the rising speed V1 of the moving platform and the base speed V2 of the screw feed mechanism, monitor the ultrasonic frequency f in real time, and calculate the density correction coefficient K(f) according to the formula, K(f) = ρ 实际 / ρ 理论 , where ρ 理论 ρ is the theoretical density value of tungsten powder. 实际 This represents the actual powder density value at the current ultrasonic frequency f; S3. Dynamically adjust the actual feed rate V2' according to K(f), where V2' = V2 × K(f) × α, and α is the tungsten powder characteristic compensation coefficient, with a value range of 0.85-1.15, and ensure that V1 / V2' = πD 2 / 4, where D is the inner diameter of the powder-filling sleeve; S4. Start motor A, motor C, motor B, transducer A, and transducer B. Utilize the vertical vibration generated by transducer A and the horizontal vibration generated by transducer B to couple and form a three-dimensional composite ultrasonic field. Make the moving platform move upward at a rate of V1 to achieve layered filling and vibration composite operation. S5. When the powder loading time reaches T=L / V1, first turn off motors A and C, then turn off the ultrasonic generator after a first delay, and then turn off motor B after a second delay to complete the powder loading operation. Here, T is the powder loading time and L is the length of the powder loading sleeve.

9. A method for improving the uniformity of powder packing density in tungsten rods according to claim 8, characterized in that, In step S5, the first time is 2 seconds, which is used to use the residual vibration generated by the ultrasonic generator in conjunction with transducer A and transducer B to continue densifying the tungsten powder.

10. A method for improving the uniformity of powder packing density in tungsten rods according to claim 8, characterized in that, In step S5, the second time is 2 seconds, which is used to perform post-leveling by the leveling mechanism after the powder stabilizes, so that the amount of powder in each powder loading chamber is consistent.

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