A method for manufacturing a hollow powder metallurgical part with complex internal cavity structure

Abstract

The application discloses to the technical field of powder metallurgy, and particularly relates to a method for manufacturing a hollow powder metallurgy part with a complex inner cavity structure, which comprises the following steps: step one: mold preparation, providing a set of detachable multi-component molds, the inner cavity shape of which is completely matched with the shape of the part to be manufactured; step two: preparation and loading of feed, preparing a powder metallurgy feed, and loading the mixed particles into the mold; and step three: planetary swing forming, installing the sealed mold loaded with the mixed particles onto a planetary swing forming device; the method has the beneficial effect that the independent swing of each station is driven by the planetary revolution, and the intermittent turning of the mold is automatically completed in the revolution gap, so that the mold cyclically changes the posture in the space in the mode of 'turning while swinging', thereby allowing the internal particles to be uniformly attached to the inner wall of the mold under the condition of no centrifugal overload and no flow dead zone, and finally realizing the forming effect of high density and high uniformity.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy technology, specifically to a method for manufacturing hollow powder metallurgy parts with complex internal cavity structures. Background Technology

[0002] Powder metallurgy (PM) is an advanced technology for preparing metal materials and forming parts. It uses metal powders as raw materials and, through a series of processes including forming and sintering, manufactures final metal materials, composite materials, and various types of products. Due to its advantages such as high material utilization, near-net-shape forming capabilities, the ability to prepare special materials, and excellent economies of scale in mass production, this technology has been widely used in the automotive, aerospace, electronics, medical device, and machinery manufacturing industries.

[0003] Currently, the mainstream powder metallurgy forming processes mainly include die compaction, metal injection molding (MIM), isostatic pressing, and powder casting.

[0004] 1. Traditional Compression Molding: This is the most commonly used process, where metal powder is pressed unidirectionally or bidirectionally using a rigid mold to form a compact with the desired shape and size. However, this process has inherent limitations. First, due to friction between powder particles and between the powder and the mold wall, pressure transmission is uneven during compression, resulting in uneven density distribution within the compact. This phenomenon is particularly severe in parts with large heights or complex shapes, affecting the mechanical properties of the final product. Second, compression molding can only form structures with internal holes and straight steps; it is extremely difficult or even impossible to manufacture lateral holes, grooves, and internal undercut structures.

[0005] 2. Metal Injection Molding (MIM): MIM technology combines the advantages of plastic injection molding and powder metallurgy, enabling the manufacture of small, high-precision parts with highly complex geometries. This process involves mixing metal powder with a binder to form a "feed," which is then injected into a mold using an injection molding machine. While MIM is superior to traditional pressing in molding complex parts (including some with external undercuts), it also faces challenges. Its molds are expensive, and it cannot meet the requirements for complex internal undercut structures.

[0006] In summary, existing powder metallurgy forming technologies face a series of technical bottlenecks when manufacturing parts with hollow structures, especially those with severely undercut internal cavities. These bottlenecks include complex mold structures, high costs, difficulties in demolding, and even the inability to form parts at all. Furthermore, the uneven distribution of metal powder and particulate materials within the mold during the manufacturing process negatively impacts the quality of the finished parts. Therefore, there is an urgent need to develop a novel, low-cost, and highly flexible powder metallurgy forming method to overcome the limitations of existing technologies and meet the growing market demand for complex structural metal parts. Summary of the Invention

[0007] The purpose of this invention is to provide a method for manufacturing hollow powder metallurgy parts with complex internal cavity structures, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for manufacturing hollow powder metallurgy parts with complex internal cavity structures, comprising the following steps: Step 1: Mold Preparation A set of detachable multi-part molds is provided, the internal cavity shape of which perfectly matches the shape of the part to be manufactured; Step 2: Feed preparation and filling To prepare powder metallurgy feedstock, mixed particles are loaded into a mold. Step 3: Planetary rocking molding A sealed mold containing mixed particles is installed on a planetary oscillating molding device. Through the combined motion of revolution, oscillation and intermittent flipping, the particle material in the mold is continuously forced to flow in multiple dimensions, thereby achieving uniform, dense and seamless spreading and bonding along the inner wall of the mold. Step 4: Heating and Adhesion Molding While the mold is undergoing a planetary oscillating motion, the heating system slowly and evenly heats the mold, gradually increasing its temperature from room temperature to a preset adhesion temperature, such as 80°C. Step 5: Cooling and Demolding After the adhesion molding is completed, stop heating and allow the mold to cool slowly to room temperature while maintaining or adjusting the oscillating motion; Step Six: Follow-up Processing The removed hollow part blanks then undergo a sintering process.

[0009] As a further embodiment of the present invention, in step one, the mold is designed to be fully openable along one or more parting surfaces so that the part with the complex undercut structure can be removed from the mold cavity without obstruction after molding. In step two, the feed is a granular mixture made by mixing metal powder and low-melting-point binder, and granulation is performed to ensure that the particle size is consistent. Based on the design volume, wall thickness and target green density of the part to be manufactured, the total weight of the required mixed particles is accurately calculated, and the calculated weight of mixed particles is added to the assembled mold cavity in multiple batches, and then the mold is sealed.

[0010] As a further embodiment of the present invention, in step four, at this temperature, the heat-sensitive binder in the mixed particles begins to soften and become sticky; due to the planetary oscillating motion, the mixed particles continuously and gently tumble in the mold cavity and come into contact with all surfaces of the mold inner wall, and the sticky particles will adhere uniformly to the mold inner wall one by one and layer by layer; this process continues for a sufficiently long time until all the added mixed particles adhere to the mold inner wall, forming a hollow part blank with a uniform wall thickness; In step five, cooling can be achieved through natural cooling or forced air cooling. Once the mold and the internal green blank have completely cooled and the adhesive has re-cured, stop the planetary machine and remove the mold from the machine. Then, slowly disassemble the multi-part mold along the parting surface one by one to remove the complete hollow part green blank. Since the mold is completely separable, even if the part has severe internal undercuts, it can be demolded smoothly. In step six, hot degreasing is performed at a sintering temperature between 200-500℃ to remove the binder from the green body. Subsequently, sintering is carried out at high temperature to metallurgically bond the metal powder particles and densify them to form the final metal parts with the required mechanical properties and dimensional accuracy.

[0011] As a further embodiment of the present invention, a planetary oscillating molding device is provided for planetary oscillation in step three. The planetary oscillating molding device includes a worktable, an annular guide rail and an annular crown gear are fixedly installed on the upper end of the worktable, an intermittent turntable is fixedly installed on the upper end of the intermittent turntable, a cross-shaped rotating support platform is fixedly installed on the upper end of the rotating support platform, a slide block is fixedly connected in a ring array at the lower end of the rotating support platform, the slide block is slidably installed on the upper end of the annular guide rail, four oscillating mechanisms are fixedly installed in a ring array on the upper end of the rotating support platform, a transmission mechanism for driving the oscillating mechanism to oscillate is installed at the lower end of the oscillating mechanism, a flipping mechanism is installed inside the oscillating mechanism, and a clamping mechanism for clamping the mold body is installed inside the flipping mechanism.

[0012] As a further embodiment of the present invention, the upper end of the rotating support platform is provided with four rotating slots in a circular array. The rocking mechanism includes a rocking seat disposed above the rotating slots. The outer side of the rocking seat is symmetrically fixedly connected with a rotating shaft. The outer sides of the two rotating shafts are rotatably connected to a support plate via bearings. The lower end of the support plate is fixedly connected to the upper end of the rotating support platform. The two support plates are symmetrically provided with arc-shaped slots on the side close to each other. The outer side of the rocking seat is symmetrically fixedly connected with an arc-shaped plate. The arc-shaped plate is slidably connected to the adjacent arc-shaped slot. The transmission mechanism is installed at the lower end of the rocking seat.

[0013] As a further embodiment of the present invention, the transmission mechanism includes a transmission shaft rotatably mounted in a rotating groove. A transmission gear is fixedly sleeved on the outer side of the transmission shaft. The lower end of the transmission gear meshes with an annular crown gear. A circular plate is fixedly sleeved on one end of the transmission shaft in the rotating groove. A drive rod is fixedly connected to the side of the circular plate away from the transmission gear. A swing plate is provided on the side of the circular plate away from the transmission gear. The upper end of the swing plate is fixedly connected to the lower end of the swing seat. A swing groove is formed through the side of the swing plate, and the drive rod extends into the swing groove.

[0014] As a further embodiment of the present invention, the flipping mechanism includes a mounting base rotatably mounted inside the rocker seat. A round shaft is symmetrically fixedly connected to the outer side of the mounting base. The round shaft is rotatably connected to the rocker seat through a bearing. Sliding grooves are symmetrically opened on both inner side walls of the mounting base. An internal threaded sleeve is symmetrically fixedly connected to the outer side of the mounting base. One of the round shafts is driven by the motor shaft of a stepper motor fixedly mounted on the side of the rocker seat.

[0015] As a further embodiment of the present invention, the clamping mechanism includes a clamping seat symmetrically slidably installed in the mounting base, and sliders symmetrically fixedly connected to both sides of the clamping seat. The sliders are slidably connected to adjacent sliding grooves, and a locking hole is provided on the side of the slider away from the clamping seat. A locking component for fixing the slider is installed in the internal threaded sleeve. The locking assembly includes a locking bolt threaded into an internal threaded sleeve, and a locking rod fixedly connected to the end of the locking bolt, the locking rod being inserted into a locking hole.

[0016] As a further embodiment of the present invention, a locking mechanism is fixedly installed on one side of the rocker seat, and an annular block is fixedly sleeved on the end of the circular shaft away from the mounting seat. The side of the annular block is provided with slots in an annular array, and the locking mechanism is used to lock the annular block.

[0017] As a further embodiment of the present invention, the locking mechanism includes a limiting plate fixedly connected to the side of the rocker seat. An L-shaped locking plate is slidably installed on the upper end of the limiting plate, and the lower end of the L-shaped locking plate passes through the limiting plate downward. The lower end of the L-shaped locking plate is adapted to the slot. A guide slide rod is inserted downward through the upper end of the limiting plate. The upper end of the guide slide rod is fixedly connected to the L-shaped locking plate. A bracket is fixedly connected to the lower end of the guide slide rod. A return spring is sleeved on the outer side of the lower end of the guide slide rod. A pressing wheel is rotatably installed on the lower end of the bracket. The upper end of the workbench is fixedly connected to four extrusion plates in a circular array, and the upper end of the extrusion plates is symmetrically provided with extrusion slopes. The guide slide rod is slidably connected to the limiting plate, the extrusion plate is located on the path of rotation of the bracket and the extrusion wheel, and the two ends of the return spring abut against the limiting plate and the bracket respectively.

[0018] The beneficial effects of this invention are: 1. The cross-shaped rotating support table is driven to rotate by an intermittent turntable. The rotating support table drives the components on it to revolve intermittently around the central axis. The direction of the revolution alternates periodically. For example, it rotates 360 degrees clockwise, then 360 degrees counterclockwise, and then 360 degrees clockwise again, and so on. When the rotating support table drives the above mechanism to rotate between two adjacent extrusion plates, during the revolution, the transmission gear in the transmission mechanism rolls along the upper end of the ring crown gear. The transmission mechanism converts the circular motion of the revolution into the reciprocating oscillation of the swing mechanism. The oscillation motion is centered on the rotating shaft, causing the mold body to swing repeatedly within a small angle range, simulating the action of artificial "shaking". 2. When the orbit reaches a specific phase, that is, after orbiting 90 degrees, the locking mechanism and the extrusion plate come into contact, causing the locking mechanism to release the lock on the ring block and the mounting base. Then, the stepper motor drives the mounting base to drive the mold body to perform intermittent 90-degree rotations. The rotation also adopts alternating forward and reverse rotations. For example, after rotating forward 360 degrees, it rotates in reverse 360 ​​degrees, and then rotates forward 360 degrees again. This ensures that the mounting base and clamping mechanism return to their original positions after completing a full rotation, preventing the heating system's wiring harness from getting tangled and damaged. Through the compound motion of "orbiting + swinging + intermittent rotation", the particle material in the mold is continuously forced to flow in multiple dimensions, thereby achieving uniform, dense, and dead-angle-free spreading and bonding along the inner wall of the mold.

[0019] 3. The device of this application uses planetary revolution to drive each station to swing independently, and automatically completes the intermittent flipping of the mold during the revolution interval, so that the mold changes its posture in space in a "shaking and flipping" manner, thereby allowing the internal particles to be uniformly attached to the inner wall of the mold under the condition of no centrifugal overload and no flow dead zone, ultimately achieving a high density and high uniformity molding effect. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the planetary swing molding device of the present invention; Figure 2 This is a cross-sectional view of the planetary swing molding device of the present invention. Figure 3 for Figure 2 Enlarged schematic diagram of the structure at point A in the middle; Figure 4 for Figure 2 Enlarged schematic diagram of the structure at point B; Figure 5 for Figure 2 Enlarged schematic diagram of the structure at point C; Figure 6 This is a schematic diagram of the rocking seat, flipping mechanism, and locking mechanism of the present invention; Figure 7 This is an exploded view of the rotating support platform, swing mechanism, and transmission mechanism of the present invention. Figure 8 This is a cross-sectional view of the flipping mechanism and clamping mechanism of the present invention; Figure 9 This is an exploded view of the flipping mechanism and clamping mechanism of the present invention.

[0021] In the diagram: 1. Worktable; 11. Annular guide rail; 12. Annular crown gear; 13. Intermittent turntable; 14. Rotary support table; 15. Rotary groove; 16. Slide seat; 2. Swing seat; 21. Rotating shaft; 22. Support plate; 23. Arc groove; 24. Arc plate; 3. Drive shaft; 31. Drive gear; 32. Circular plate; 33. Drive rod; 34. Swing plate; 35. Swing groove; 4. Mounting seat; 41. Slide groove; 42. Internal threaded sleeve; 43. Round shaft; 44. Annular block; 45. Slot; 46. Mold body; 5. Clamping seat; 51. Slider; 52. Locking hole; 53. Locking bolt; 54. Locking rod; 6. Limiting plate; 61. L-shaped locking plate; 62. Guide slide rod; 63. Bracket; 64. Return spring; 65. Extrusion wheel; 7. Extrusion plate; 71. Extrusion slope. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all 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.

[0023] Please see Figures 1 to 9 This invention provides a technical solution: a method for manufacturing hollow powder metallurgy parts with complex internal cavity structures, characterized by comprising the following steps: Step 1: Mold Preparation A set of detachable multi-part molds is provided, the inner cavity shape of which is perfectly matched with the shape of the part to be manufactured. The mold is designed to be fully opened along one or more parting surfaces so that the part with complex undercut structure can be removed from the mold cavity without obstruction after molding. Step 2: Feed preparation and filling The powder metallurgy feedstock is prepared by mixing metal powder and low-melting-point binder to form a granular mixture, which is then granulated to ensure uniform particle size. Based on the design volume, wall thickness and target green density of the part to be manufactured, the total weight of the required mixed particles is accurately calculated, and the calculated weight of the mixed particles is added to the assembled mold cavity in multiple batches, and then the mold is sealed. Step 3: Planetary rocking molding Please see Figures 1 to 9 A planetary oscillating molding device is provided for planetary oscillation in step three. The planetary oscillating molding device includes a worktable 1. An annular guide rail 11 and an annular crown gear 12 are fixedly installed on the upper end of the worktable 1. The annular guide rail 11 is located outside the annular crown gear 12, and the annular guide rail 11 and the annular crown gear 12 are coaxial. An intermittent rotary table 13 is fixedly installed on the upper end of the worktable 1. The output shaft and indexing plate of the intermittent rotary table 13 are coaxial with the annular crown gear 12. A cross-shaped rotating support platform 14 is fixedly installed on the upper end of the intermittent rotary table 13. The lower end of the rotating support platform 14 is fixedly connected to slides 16 in a circular array. The slide block 16 is slidably mounted on the upper end of the annular guide rail 11. Four swinging mechanisms are fixedly mounted in a circular array on the upper end of the rotating support platform 14. The number of swinging mechanisms can be increased or decreased according to actual needs. A transmission mechanism for driving the swinging mechanism to swing is installed at the lower end of the swinging mechanism. A flipping mechanism is installed inside the swinging mechanism. A clamping mechanism for clamping the mold body 46 is installed inside the flipping mechanism. A heating system for heating the mold body 46 is installed inside the clamping mechanism. The heating system for the mold is prior art to those skilled in the art and will not be described in detail here. It is sufficient to meet the requirement of heating the mold.

[0024] The intermittent turntable 13 drives the rotating support table 14 to rotate intermittently. Each time, the intermittent turntable 13 drives the rotating support table 14 to rotate 90 degrees. After the intermittent turntable 13 drives the rotating support table 14 to rotate 360 ​​degrees, the intermittent turntable 13 drives the rotating support table 14 to rotate in the opposite direction until the rotating support table 14 is driven by the intermittent turntable 13 to rotate 360 ​​degrees and then rotates in the forward direction again. This process is repeated. For example, the intermittent turntable 13 drives the rotating support platform 14 to rotate 90 degrees clockwise intermittently. After the rotating support platform 14 has rotated 360 degrees from its initial position, the intermittent turntable 13 drives the rotating support platform 14 to rotate 90 degrees counterclockwise intermittently. After the rotating support platform 14 has rotated 360 degrees from its initial position, the intermittent turntable 13 drives the rotating support platform 14 to rotate clockwise intermittently again, and so on.

[0025] The rotation angle of the intermittent turntable 13 at each interval is related to the number of swing mechanisms. When the number of swing mechanisms changes, the rotation angle of the intermittent turntable 13 at each interval is also adjusted accordingly. The number of swing mechanisms is n, and the rotation angle of the intermittent turntable 13 at each interval is 360° / n. When the rotating support platform 14 rotates, it drives the mold body 46 to rotate synchronously. At this time, the transmission mechanism rolls along the ring crown gear 12 and drives the swing mechanism to swing through the transmission mechanism. The swing mechanism drives the mold body 46 to swing synchronously through the flipping mechanism and the clamping mechanism, so that the mold body 46 revolves at a low speed around the output axis of the intermittent turntable 13, while flipping and swinging, so that the added particles flow evenly along the mold wall.

[0026] When the rotating support platform 14 rotates 90 degrees, the flipping mechanism drives the clamping mechanism and the mold body 46 to flip 90 degrees. When the rotating support platform 14 rotates 360 degrees, the flipping mechanism drives the mold body 46 to flip 360 degrees. When the rotating support platform 14 rotates in the opposite direction, the flipping mechanism drives the clamping mechanism to rotate in the opposite direction. This process is repeated to allow the mold body 46 to rotate.

[0027] The mold is shaken and then rotated 90 degrees, and then shaken and wobbled again; this process is repeated until the mold completes a full 360-degree rotation and returns to its original position, thereby achieving uniform spreading and adhesion of particles along the inner wall of the mold.

[0028] A sealed mold containing mixed particles is installed on a planetary oscillating molding device. Through the combined motion of revolution, oscillation and intermittent flipping, the particle material inside the mold is continuously forced to flow in multiple dimensions, thereby achieving uniform, dense and seamless spreading and bonding along the inner wall of the mold.

[0029] Step 4: Heating and Adhesion Molding While the mold is undergoing a planetary oscillating motion, the heating system slowly and evenly heats the mold, gradually increasing its temperature from room temperature to a preset adhesion temperature, such as 80°C. At this temperature, the heat-sensitive binder in the mixed particles begins to soften and become sticky. As the planetary oscillating motion causes the mixed particles to continuously and gently tumble within the mold cavity and come into contact with all surfaces of the mold's inner wall, the viscous particles will adhere evenly to the mold's inner wall one by one and layer by layer. This process continues for a sufficiently long time until all the added mixed particles adhere to the mold's inner wall, forming a hollow part blank with a uniform wall thickness.

[0030] Step 5: Cooling and Demolding After the adhesion molding is completed, stop heating and allow the mold to cool slowly to room temperature while maintaining or adjusting the oscillating motion. Cooling can be achieved through natural cooling or forced air cooling. Once the mold and the internal green body have completely cooled and the adhesive has re-cured, stop the planetary machine and remove the mold from the machine. Then, slowly disassemble the multi-part mold along the parting surface one by one to remove the complete hollow part green body. Since the mold is completely separable, even if the part has severe internal undercuts, it can be demolded smoothly.

[0031] Step Six: Follow-up Processing The hollow part blanks are then subjected to a sintering process. The sintering temperature is between 200-500℃ for hot degreasing, which aims to remove the binder in the blanks. The subsequent sintering is a metallurgical bonding of metal powder particles at high temperature, densifying them to form the final metal part with the required mechanical properties and dimensional accuracy.

[0032] Please see Figure 1 , Figure 2 , Figure 6 and Figure 7 The upper end of the rotating support platform 14 has four rotating slots 15 arranged in a ring array. The number of rotating slots 15 is the same as the number of swing mechanisms. The swing mechanism includes a swing seat 2 set above the rotating slots 15. The outer side of the swing seat 2 is symmetrically fixedly connected to a rotating shaft 21. The outer sides of the two rotating shafts 21 are rotatably connected to a support plate 22 through bearings. The lower end of the support plate 22 is fixedly connected to the upper end of the rotating support platform 14. The two support plates 22 support and limit the swing seat 2. The two support plates 22 are symmetrically provided with arc-shaped slots 23 on the side of the two support plates 22 that are close to each other. The outer side of the swing seat 2 is symmetrically fixedly connected with an arc plate 24. The arc plate 24 is slidably connected to the adjacent arc-shaped slot 23. The arc plate 24 and the arc-shaped slot 23 have the same curvature. The arc plate 24 and the arc-shaped slot 23 are coaxial with the rotating shaft 21. The transmission mechanism is installed at the lower end of the swing seat 2.

[0033] When the transmission mechanism drives the rocker seat 2 to swing back and forth, the rocker seat 2 rotates back and forth around the axis of the rotating shaft 21. When the rocker seat 2 swings and rotates, it drives the arc plate 24 to slide along the arc groove 23, so that the rocker seat 2 can swing stably.

[0034] Please see Figures 2 to 4 ,Figure 7 The transmission mechanism includes a transmission shaft 3 rotatably mounted in a rotating groove 15. A transmission gear 31 is fixedly sleeved on the outer side of the transmission shaft 3. The lower end of the transmission gear 31 meshes with a ring crown gear 12. A circular plate 32 is fixedly sleeved on one end of the transmission shaft 3 in the rotating groove 15. A drive rod 33 is fixedly connected to the side of the circular plate 32 away from the transmission gear 31. A roller is rotatably mounted on the outer side of the drive rod 33. A swing plate 34 is provided on the side of the circular plate 32 away from the transmission gear 31. The upper end of the swing plate 34 is fixedly connected to the lower end of the swing seat 2. A swing groove 35 is opened through the side of the swing plate 34. The drive rod 33 extends into the swing groove 35, and the roller on the outer side of the drive rod 33 rolls in contact with the swing groove 35. The lower end of the swing plate 34 extends into the rotating groove 15.

[0035] When the intermittent turntable 13 drives the rotating support table 14 to rotate, the rotating support table 14 drives the transmission mechanism to move synchronously. Since the transmission gear 31 meshes with the ring crown gear 12, when the transmission gear 31 rotates with the rotating support table 14, the transmission gear 31 rolls along the upper end of the ring crown gear 12. The transmission gear 31 drives the transmission shaft 3 to rotate, the transmission shaft 3 drives the circular plate 32 to rotate, the circular plate 32 drives the drive rod 33 to rotate, and the drive rod 33 drives the roller to roll along the swing groove 35. At the same time, the drive rod 33 pushes the swing plate 34 to swing back and forth through the roller. The swing plate 34 drives the swing seat 2 to swing back and forth around the rotating shaft 21, thereby driving the transmission mechanism to swing back and forth.

[0036] Please see Figure 2 , Figure 8 and Figure 9 The flipping mechanism includes a mounting base 4 rotatably mounted inside the rocker seat 2. A round shaft 43 is symmetrically fixedly connected to the outer side of the mounting base 4. The round shaft 43 is rotatably connected to the rocker seat 2 through bearings. The mounting base 4 is rotatably mounted inside the rocker seat 2 through the round shaft 43. The two inner side walls of the mounting base 4 are symmetrically provided with sliding grooves 41. An internal threaded sleeve 42 is symmetrically fixedly connected to the outer side of the mounting base 4. One end of the internal threaded sleeve 42 communicates with the sliding groove 41. One of the round shafts 43 is driven by the motor shaft of a stepper motor fixedly mounted on the side of the rocker seat 2. The round shaft 43 passes through the rocker seat 2. The motor shaft and the round shaft 43 are connected by a coupling.

[0037] Each time the stepper motor shaft rotates 90 degrees, or one-quarter of a circumference, the motor shaft drives the mounting base 4 to rotate 90 degrees through the circular shaft 43. The mounting base 4 rotates around the rocker seat 2 with the circular shaft 43 as the center. The mounting base 4 drives the mold body 46 to rotate 90 degrees through the clamping mechanism. When the motor shaft rotates 360 degrees, the motor shaft rotates in the opposite direction until it rotates 360 degrees again, and so on.

[0038] Please see Figure 2 ,Figure 8 and Figure 9 The clamping mechanism includes clamping seats 5 symmetrically slidably installed in the mounting base 4. During operation, the mold body 46 is placed at the bottom of the inner side of the mounting base 4, so that the two clamping seats 5 are symmetrically clamped on the outer side of the mold body 46, thereby clamping and fixing the mold body 46. Slider 51 is symmetrically fixedly connected to both sides of the clamping seats 5. The slider 51 is slidably connected to the adjacent slide groove 41. A locking hole 52 is opened on the side of the slider 51 away from the clamping seat 5. A locking component for fixing the slider 51 is installed in the internal threaded sleeve 42.

[0039] Both the mounting base 4 and the clamping base 5 are equipped with heating systems, which can effectively heat the mold body 46.

[0040] The locking assembly includes a locking bolt 53 threaded into the internal threaded sleeve 42. A locking rod 54 is fixedly connected to the end of the locking bolt 53. The locking rod 54 is inserted into the locking hole 52. The diameter of the locking rod 54 is smaller than the diameter of the internal thread of the internal threaded sleeve 42 closest to the axis. When the locking bolt 53 is screwed into the internal threaded sleeve 42, the locking rod 54 can pass through the inner cavity of the internal threaded sleeve 42 without obstruction.

[0041] When it is necessary to clamp and fix the mold body 46, first place the mold body 46 at the bottom of the inner side of the mounting base 4, and then insert the two clamping seats 5 into the mounting base 4. The clamping seats 5 drive the slider 51 into the slide groove 41, so that the two clamping seats 5 are symmetrically clamped on the outside of the mold body 46. At this time, the slider 51 is completely inserted into the slide groove 41, and the locking hole 52 on the side of the slider 51 is aligned with the inner cavity of the adjacent internal thread sleeve 42. Screw the locking bolt 53 into the internal threaded sleeve 42. The locking bolt 53 drives the locking rod 54 to be inserted into the locking hole 52. The locking assembly locks the slider 51, thereby locking the clamping seat 5, so that the two clamping seats 5 can firmly clamp and fix the mold body 46.

[0042] During disassembly, first unscrew the locking bolt 53 from the internal threaded sleeve 42 to separate the locking rod 54 from the locking hole 52, thereby releasing the locking assembly from locking the slider 51. At this time, the two clamping seats 5 can be separated, allowing the clamping seats 5 to release their clamping and fixing of the mold body 46, thus allowing the mold body 46 to be disassembled.

[0043] The two clamping seats 5 here can be set to move automatically as needed, and driven by hydraulic cylinders or the like to move closer or further apart, so that the clamping seats 5 clamp or release the mold body 46.

[0044] Please see Figure 2 , Figure 5 , Figure 6 and Figure 9A locking mechanism is fixedly installed on one side of the rocker seat 2. The locking mechanism and the stepper motor are symmetrically distributed on both sides of the rocker seat 2. One end of the round shaft 43 passes through the rocker seat 2 and extends to the outside. The end of the round shaft 43 away from the mounting base 4 is fixedly sleeved with an annular block 44. The side of the annular block 44 has slots 45 arranged in an annular array. The locking mechanism is used to lock the annular block 44.

[0045] The locking mechanism includes a limiting plate 6 fixedly connected to the side of the rocker seat 2. An L-shaped locking plate 61 is slidably installed on the upper end of the limiting plate 6. The lower end of the L-shaped locking plate 61 passes through the limiting plate 6 downwards. The lower end of the L-shaped locking plate 61 is adapted to the slot 45. A guide slide rod 62 is inserted through the upper end of the limiting plate 6 downwards. The upper end of the guide slide rod 62 is fixedly connected to the L-shaped locking plate 61. A bracket 63 is fixedly connected to the lower end of the guide slide rod 62. A return spring 64 is sleeved on the outer side of the lower end of the guide slide rod 62. A pressing wheel 65 is rotatably installed on the lower end of the bracket 63. The upper end of the workbench 1 is fixedly connected with four extrusion plates 7 in a ring array, and the upper end of the extrusion plates 7 is symmetrically provided with extrusion slopes 71.

[0046] The guide slide rod 62 is slidably connected to the limiting plate 6. The extrusion plate 7 is located on the rotation path of the bracket 63 and the extrusion wheel 65. The two ends of the return spring 64 abut against the limiting plate 6 and the bracket 63 respectively. The return spring 64 applies elastic force to the bracket 63. When the extrusion wheel 65 contacts the extrusion plate 7, the extrusion wheel 65 rolls along the extrusion slope 71.

[0047] Initially, the extrusion wheel 65 abuts against the upper end of the extrusion plate 7. At this time, the extrusion wheel 65 moves upward to the highest position. The extrusion wheel 65 drives the guide slide rod 62 and the L-shaped locking plate 61 to move upward through the bracket 63, so that the lower end of the L-shaped locking plate 61 separates from the slot 45. The bracket 63 squeezes the return spring 64. At this time, the locking mechanism releases the lock on the annular block 44. At this time, the round shaft 43 and the mounting base 4 are not locked and can be flipped. After the mold body 46 is installed or after the mold body 46 is flipped and adjusted, the locking mechanism is rotated synchronously by the rotating support table 14 through the rocker seat 2, so that the locking mechanism is away from the extrusion plate 7. Under the action of the return spring 64, the bracket 63 is pushed to move downward. The bracket 63 drives the L-shaped locking plate 61 to move downward through the guide slide rod 62, so that the lower end of the L-shaped locking plate 61 is inserted into the slot 45, thereby locking the ring block 44. Since the ring block 44 is fixedly connected to the round shaft 43, the round shaft 43 and the mounting seat 4 are locked, so that the mounting seat 4 cannot be flipped at will. At the same time, when the rocker mechanism drives the mounting seat 4, the clamping mechanism and the mold body 46 to rock, it prevents the mounting seat 4 from becoming loose or shaking, and ensures the rocking effect. When the rotating support platform 14 rotates 90 degrees, the extrusion wheel 65 in the locking mechanism approaches another extrusion plate 7, causing the extrusion wheel 65 to roll along the extrusion slope 71 to the upper end of the extrusion plate 7, thereby releasing the locking mechanism from locking the ring block 44, which facilitates the rotational adjustment of the mounting base 4 and the mold body 46.

[0048] Working principle: The planetary motion is driven by the intermittent turntable 13 to rotate the cross-shaped rotating support platform 14. The rotating support platform 14 drives all the crank mechanism, transmission mechanism, flipping mechanism, clamping mechanism, mold body 46 and locking mechanism on it to revolve intermittently around the central axis. The direction of revolution alternates periodically. For example, after rotating 360 degrees clockwise, it rotates 360 degrees counterclockwise, and then rotates 360 degrees clockwise again, and so on. The oscillating rotation stage oscillation occurs when the rotating support table 14 drives the above mechanism to rotate between two adjacent extrusion plates 7. During the revolution, the transmission gear 31 in the transmission mechanism rolls along the upper end of the ring crown gear 12. The transmission mechanism converts the circumferential motion of the revolution into the reciprocating oscillation of the oscillating mechanism. The oscillating motion is centered on the rotating shaft 21, causing the mold body 46 to swing repeatedly within a small angle range, simulating the artificial "shaking" action. When the orbit reaches a specific phase, that is, after orbiting 90 degrees, the locking mechanism comes into contact with the extrusion plate 7, causing the locking mechanism to release the lock on the annular block 44 and the mounting base 4. Then, the stepper motor drives the mounting base 4 to drive the mold body 46 to perform intermittent 90-degree rotations. The rotation also adopts alternating forward and reverse rotations. For example, after rotating forward 360 degrees, it rotates in reverse 360 ​​degrees, and then rotates forward 360 degrees again, ensuring that the mounting base 4 and the clamping mechanism return to their original positions after completing a full rotation, preventing the heating system's wiring harness from becoming entangled and damaged.

[0049] The device in this application utilizes planetary revolution to drive each station to swing independently, and automatically completes the intermittent flipping of the mold during the revolution interval. This allows the mold to change its posture in space in a "swinging and flipping" manner, so that the internal particles can be uniformly attached to the inner wall of the mold without centrifugal overload or flow dead zone, ultimately achieving a high-density and high-uniformity molding effect.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing hollow powder metallurgy parts with complex internal cavity structures, characterized in that: Includes the following steps: Step 1: Mold Preparation A set of detachable multi-part molds is provided, the internal cavity shape of which perfectly matches the shape of the part to be manufactured; Step 2: Feed preparation and filling To prepare powder metallurgy feedstock, mixed particles are loaded into a mold. Step 3: Planetary rocking molding A sealed mold containing mixed particles is installed on a planetary oscillating molding device. Through the combined motion of revolution, oscillation and intermittent flipping, the particle material in the mold is continuously forced to flow in multiple dimensions, thereby achieving uniform, dense and seamless spreading and bonding along the inner wall of the mold. Step 4: Heating and Adhesion Molding While the mold is undergoing a planetary oscillating motion, the heating system slowly and evenly heats the mold, gradually increasing its temperature from room temperature to a preset adhesion temperature, such as 80°C. Step 5: Cooling and Demolding After the adhesion molding is completed, stop heating and allow the mold to cool slowly to room temperature while maintaining or adjusting the oscillating motion; Step Six: Follow-up Processing The removed hollow part blanks then undergo a sintering process.

2. The method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 1, characterized in that: In step one, the mold is designed to be fully opened along one or more parting surfaces so that parts with complex undercut structures can be removed from the mold cavity without obstruction after molding; In step two, the feed is a granular mixture made by mixing metal powder and low-melting-point binder, and then granulated to ensure uniform particle size. Based on the design volume, wall thickness, and target green density of the part to be manufactured, the total weight of the required mixed particles is accurately calculated, and the calculated weight of mixed particles is added to the assembled mold cavity in multiple batches, and then the mold is sealed.

3. The method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 1, characterized in that: In step four, at this temperature, the heat-sensitive binder in the mixed particles begins to soften and become sticky; due to the planetary tumbling motion, the mixed particles continuously and gently tumble in the mold cavity and come into contact with all surfaces of the mold wall, the sticky particles will adhere evenly to the mold wall one by one and layer by layer; continue this process for a sufficiently long time until all the added mixed particles adhere to the mold wall, forming a hollow part blank with a uniform wall thickness; In step five, cooling can be achieved through natural cooling or forced air cooling. Once the mold and the internal green blank have completely cooled and the adhesive has re-cured, stop the planetary machine and remove the mold from the machine. Then, slowly disassemble the multi-part mold along the parting surface one by one to remove the complete hollow part green blank. Since the mold is completely separable, even if the part has severe internal undercuts, it can be demolded smoothly. In step six, hot degreasing is performed at a sintering temperature between 200-500℃ to remove the binder from the green body. Subsequently, sintering is carried out at high temperature to metallurgically bond the metal powder particles and densify them to form the final metal parts with the required mechanical properties and dimensional accuracy.

4. The method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 1, characterized in that: A planetary oscillating molding device is provided for planetary oscillation in step three. The planetary oscillating molding device includes a worktable (1), an annular guide rail (11) and an annular crown gear (12) are fixedly installed on the upper end of the worktable (1), an intermittent turntable (13) is fixedly installed on the upper end of the intermittent turntable (13), a cross-shaped rotating support platform (14) is fixedly installed on the upper end of the rotating support platform (14), a slide (16) is fixedly connected in an annular array at the lower end of the rotating support platform (14), the slide (16) is slidably installed on the upper end of the annular guide rail (11), four oscillating mechanisms are fixedly installed in an annular array on the upper end of the rotating support platform (14), a transmission mechanism for driving the oscillating mechanism to oscillate is installed at the lower end of the oscillating mechanism, a flipping mechanism is installed on the inner side of the oscillating mechanism, and a clamping mechanism for clamping the mold body (46) is installed inside the flipping mechanism.

5. A method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 4, characterized in that: The upper end of the rotating support platform (14) is provided with four rotating slots (15) arranged in a ring. The rocking mechanism includes a rocking seat (2) set above the rotating slots (15). The outer side of the rocking seat (2) is symmetrically fixedly connected with a rotating shaft (21). The outer sides of the two rotating shafts (21) are rotatably connected with a support plate (22) through a bearing. The lower end of the support plate (22) is fixedly connected to the upper end of the rotating support platform (14). The two support plates (22) are symmetrically provided with arc-shaped slots (23) on the side that is close to each other. The outer side of the rocking seat (2) is symmetrically fixedly connected with an arc plate (24). The arc plate (24) is slidably connected to the adjacent arc-shaped slot (23). The transmission mechanism is installed at the lower end of the rocking seat (2).

6. A method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 5, characterized in that: The transmission mechanism includes a transmission shaft (3) rotatably mounted in a rotating groove (15). A transmission gear (31) is fixedly sleeved on the outer side of the transmission shaft (3). The lower end of the transmission gear (31) meshes with a ring crown gear (12). A circular plate (32) is fixedly sleeved on one end of the transmission shaft (3) in the rotating groove (15). A drive rod (33) is fixedly connected to the side of the circular plate (32) away from the transmission gear (31). A swing plate (34) is provided on the side of the circular plate (32) away from the transmission gear (31). The upper end of the swing plate (34) is fixedly connected to the lower end of the swing seat (2). A swing groove (35) is opened through the side of the swing plate (34). The drive rod (33) extends into the swing groove (35).

7. A method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 5, characterized in that: The flipping mechanism includes a mounting base (4) rotatably mounted inside the rocker seat (2). A round shaft (43) is symmetrically fixedly connected to the outer side of the mounting base (4). The round shaft (43) is rotatably connected to the rocker seat (2) through a bearing. Slide grooves (41) are symmetrically opened on both inner side walls of the mounting base (4). An internal threaded sleeve (42) is symmetrically fixedly connected to the outer side of the mounting base (4). One of the round shafts (43) is driven by the motor shaft of a stepper motor fixedly mounted on the side of the rocker seat (2).

8. A method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 7, characterized in that: The clamping mechanism includes a clamping seat (5) symmetrically slidably installed in the mounting base (4). Sliders (51) are symmetrically fixedly connected to both sides of the clamping seat (5). The sliders (51) are slidably connected to the adjacent slide groove (41). A locking hole (52) is provided on the side of the slider (51) away from the clamping seat (5). A locking component for fixing the slider (51) is installed in the internal thread sleeve (42). The locking assembly includes a locking bolt (53) threaded into an internal threaded sleeve (42), and a locking rod (54) is fixedly connected to the end of the locking bolt (53), which is inserted into the locking hole (52).

9. A method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 7, characterized in that: A locking mechanism is fixedly installed on one side of the rocker seat (2), and an annular block (44) is fixedly sleeved on the end of the round shaft (43) away from the mounting seat (4). The side of the annular block (44) is provided with slots (45) in an annular array. The locking mechanism is used to lock the annular block (44).

10. A method for manufacturing hollow powder metallurgy parts with complex internal cavity structures according to claim 9, characterized in that: The locking mechanism includes a limiting plate (6) fixedly connected to the side of the rocker seat (2). An L-shaped locking plate (61) is slidably installed on the upper end of the limiting plate (6). The lower end of the L-shaped locking plate (61) passes through the limiting plate (6) downward. The lower end of the L-shaped locking plate (61) is adapted to the slot (45). A guide slide rod (62) is inserted through the upper end of the limiting plate (6) downward. The upper end of the guide slide rod (62) is fixedly connected to the L-shaped locking plate (61). A bracket (63) is fixedly connected to the lower end of the guide slide rod (62). A reset spring (64) is sleeved on the outer side of the lower end of the guide slide rod (62). A pressing wheel (65) is rotatably installed on the lower end of the bracket (63). The upper end of the workbench (1) is fixedly connected with four extrusion plates (7) in a ring array, and the upper end of the extrusion plates (7) is symmetrically provided with extrusion slopes (71). The guide slide rod (62) is slidably connected to the limiting plate (6) in the upper and lower directions. The extrusion plate (7) is located on the path of rotation of the bracket (63) and the extrusion wheel (65). The two ends of the reset spring (64) abut against the limiting plate (6) and the bracket (63) respectively.

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