Powder forming equipment and forming method for powder metallurgy

Abstract

The invention discloses powder forming equipment for powder metallurgy and a forming method, and belongs to the technical field of metal powder forming, the powder forming equipment comprises a machine body, a pressure head and a lifting table arranged under the pressure head, a powder scraping mechanism is arranged above the lifting table, the powder scraping mechanism comprises a moving seat, a horizontal guide rail is arranged on the machine body, and a horizontal guide rail is arranged on the moving seat; the moving seat is in sliding fit with the horizontal guide rail; a scraping plate is mounted in the scraping plate box, and the scraping plate box is rotationally mounted on the moving seat and can rotate around a vertical axis; the driving mechanism acts on the scraper box and is used for driving the scraper box to rotate around the vertical axis, so that the acting face of the scraper faces the current moving direction of the moving base or the direction opposite to the current moving direction of the moving base. According to the powder forming equipment and method for powder metallurgy, collaborative optimization of the structural design and the technological process is achieved in the powder scraping link, and the problems that a traditional fixed scraper is low in efficiency and poor in powder layer uniformity are effectively solved.

Description

Technical Field

[0001] This invention belongs to the field of metal powder forming technology, and particularly relates to a powder forming equipment and forming method for powder metallurgy. Background Technology

[0002] Powder metallurgy is a near-net-shape manufacturing technology that obtains dense parts by pressing metal powder into shape and then sintering it at high temperatures. It is widely used in the automotive, aerospace, power tool, and consumer electronics industries. In this process, the powder forming equipment is a key piece of equipment, and the uniformity of powder distribution directly determines the density distribution of the pressed blank, thus affecting the dimensional accuracy and mechanical properties of the final product.

[0003] A typical metal powder forming process is as follows: First, a mold cavity is formed by a lower mold and side walls; then, a powder feeding device delivers a measured amount of metal powder into the cavity; next, a scraper moves horizontally from one end of the cavity to the other, scraping away excess powder that protrudes above the upper surface of the mold cavity, making the powder layer surface smooth and of uniform thickness; then, an upper pressure head moves downward, applying high pressure to the powder, causing it to initially densify and form a green blank; finally, the green blank is ejected and sent to a sintering furnace to complete densification. In existing equipment, the scraper is usually a rigid, fixed structure, and its installation direction cannot be adjusted after the equipment is assembled, allowing only one effective scraping operation in a single direction.

[0004] Because the scraper's working surface is fixed in direction, it cannot effectively scrape powder during its return stroke; instead, it may push the powder in the opposite direction, causing localized accumulation. If two different leveling operations are required, such as first roughly scraping off excess material and then finely finishing the surface, two independent unidirectional scraping strokes must be arranged, requiring readjustment of the equipment in between, significantly extending the single forming cycle. This reliance on unidirectional scraping is not only inefficient, but also prone to causing ripples, steps, or thickness deviations on the powder layer surface due to the difficulty in precisely aligning and connecting the two scraping operations. During subsequent pressing, such uneven areas will form density gradients, leading to quality problems such as blank cracking, deformation, or dimensional deviations after sintering. Summary of the Invention

[0005] To address the aforementioned shortcomings, the present invention aims to provide a powder forming equipment and method for powder metallurgy, which enables the scraper's working surface to always face the current direction of movement, achieving truly bidirectional and effective powder scraping without the need for a reset stroke, thus improving operational efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A powder forming device and method for powder metallurgy includes a machine body, a pressure head, and a lifting platform disposed directly below the pressure head. A powder scraping mechanism is provided above the lifting platform, and the powder scraping mechanism includes: A movable base is provided on the machine body, and the movable base is slidably fitted onto the horizontal guide rail. A scraper box, wherein a scraper is installed inside the scraper box, and the scraper box is rotatably mounted on a movable base and is capable of rotating about a vertical axis; A driving mechanism acts on the scraper box to drive the scraper box to rotate about a vertical axis so that the working surface of the scraper faces the current moving direction of the moving seat or its opposite direction.

[0007] Preferably, the movable seat is driven by a cylinder, and the output direction of the cylinder is parallel to the horizontal guide rail.

[0008] Preferably, the top of the scraper box is provided with a rotating tube, and the driving mechanism acts on the rotating tube to drive the scraper box to rotate around the vertical axis.

[0009] Preferably, the driving mechanism includes two sets of racks, which are respectively located on both sides of the horizontal guide rail; a gear is mounted on the rotating tube via a one-way bearing, and when the moving seat drives the gear to move to the rack position, the gear meshes with the rack to drive the scraper box to rotate 180°; a damping mechanism is provided between the rotating tube and the moving seat.

[0010] Preferably, the scraper is rotatably connected to the scraper box via a rotating shaft in the middle and is connected to a torsion spring seat, so that the scraper forms a lever structure; a top post is provided at the end of the scraper away from the working surface, and the top post is slidably disposed in the rotating tube in the vertical direction; a spring is provided between the top post and the rotating tube.

[0011] Preferably, the movable seat is provided with a triggering mechanism, which is configured to act on the top column to change its vertical position in the rotating tube during the rotation of the scraper box around the vertical axis, thereby adjusting the tilt angle of the scraper.

[0012] Preferably, the triggering mechanism includes a first magnet and a second magnet; the first magnet is disposed on the movable seat and has a first magnetic pole region and a second magnetic pole region along the extension direction of the horizontal guide rail; the second magnet is disposed on the top column, and its polarity matches that of the first magnet, so that when the rotating tube drives the top column to rotate to the position corresponding to the first magnetic pole region, the scraper is at a first tilt angle, and when it rotates to the position corresponding to the second magnetic pole region, the scraper is at a second tilt angle.

[0013] Preferably, the triggering mechanism includes a guide surface on the lower surface of the movable seat and a protrusion on the top column; under the preload of the spring, the protrusion abuts against the guide surface upward; the guide surface is an inclined curved surface, used to drive the top column to move in the vertical direction by changing the relative position of the protrusion and the guide surface during the rotation of the scraper box, thereby adjusting the angle of the scraper.

[0014] Preferably, the guide surface is an annular curved surface, which forms a first working height and a second working height at positions corresponding to the scraper box rotating 90° and 270°, respectively; the guide surface has a vertical drop section in the rotation path, when the scraper box rotates through this drop section, the protrusion suddenly moves upward due to loss of support, causing the scraper to produce a large angle change and vibration; wherein, when the scraper box completes a 360° rotation, the working surface of the scraper faces the side away from the machine body.

[0015] This invention also protects a powder forming method for powder metallurgy, implemented using a forming device, comprising the following steps: Provide metal powder to the forming area; Move the scraper along the first direction to initially level the metal powder; At the end of the stroke, rotate the scraper so that the scraper's working surface faces a second direction opposite to the first direction; Vibration treatment of metal powder; Move the scraper along the second direction to scrape the metal powder again; Metal powder is pressed to form a blank.

[0016] In summary, the technical effects and advantages of this invention are as follows: This invention achieves synergistic optimization of structural design and process flow in the powder scraping stage of powder metallurgy forming equipment, effectively solving the problems of low efficiency and poor powder uniformity of traditional fixed scrapers.

[0017] From a processing method perspective, this scheme clearly divides the powder scraping process into three orderly stages: the first stage is rough scraping and leveling, which uses a high moving speed, a large scraper inclination angle, and a low force to quickly remove excess powder and initially level the surface; the second stage is vibration redistribution, which applies vibration at a specific frequency and amplitude to promote the natural settling of powder particles without external disturbance, eliminating internal voids and improving the uniformity of bulk density; the third stage is fine scraping and shaping, which uses a low speed, a small inclination angle, and controllable pressure for fine finishing to ensure that the final powder layer contour accurately matches the pressing requirements. This three-stage method avoids the contradiction between efficiency and precision that is difficult to achieve in a single powder scraping process, significantly improves the uniformity of green body density, and reduces the risk of sintering deformation.

[0018] From a mechanical structure perspective: First, the scraper box can rotate around a vertical axis, ensuring that the scraper's working surface always faces the current direction of movement, achieving truly bidirectional and effective powder scraping without the need for stroke reset, thus improving work efficiency; Second, the scraper adopts a lever-type installation structure, and its tilt angle is automatically adjusted by the top column and spring mechanism as the scraper box rotates, allowing for switching between coarse and fine scraping angles without independent drive; Third, the triggering mechanism can adopt either magnetic force or a mechanical guide surface. The former is contactless and maintenance-free, while the latter is compact, low-cost, and the guide surface can be further integrated with a drop section to trigger sudden vibration of the scraper in maintenance mode, achieving a self-cleaning function. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 for Figure 1 Enlarged structural diagram at point A in the diagram; Figure 3 This is a schematic diagram showing the positional relationship between the scraper box and the rotating tube in this invention; Figure 4 This is a schematic diagram showing the positional relationship between the gear and the rack in this invention; Figure 5 This is a schematic diagram of the triggering mechanism in the present invention. Figure 1 ; Figure 6 This is a schematic diagram of the triggering mechanism in the present invention. Figure 2 ; Figure 7 This is a schematic diagram of the guiding surface in this invention; Figure 8 This is a schematic diagram showing the relationship between the rotation angle of the scraper box and the moving distance of the top column in this invention.

[0020] In the diagram: 1. Lifting platform; 2. Cylinder; 3. Moving seat; 31. Horizontal guide rail; 32. First magnet; 33. Guide surface; 4. Scraper box; 41. Rotating tube; 42. Gear; 43. Rack; 5. Scraper; 51. Torsion spring seat; 6. Top column; 61. Spring; 62. Second magnet; 63. Protrusion. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] The inventors of this invention discovered that in traditional powder forming equipment, the scraping mechanism often uses scrapers with fixed direction and fixed angle, which makes it easy for the powder to be pushed in the opposite direction during reciprocating scraping, and it is impossible to dynamically adjust the scraping force according to process requirements; at the same time, there is a lack of effective cleaning methods after the scraper surface is covered with powder, which affects the long-term operational stability.

[0023] Based on this discovery, the present invention proposes a novel approach: decoupling and linking the direction adjustment and angle adjustment of the scraper, using the rotation of the scraper box 4 to drive the angle of the scraper 5 to change adaptively, and introducing a non-contact or mechanical triggering mechanism to achieve bidirectional differentiated powder scraping, further integrating the powder cleaning function.

[0024] like Figures 1-8As shown in one embodiment of the present invention, a powder forming device for powder metallurgy includes a machine body, an upper pressure head, a liftable lifting platform 1, and a powder scraping mechanism disposed above the lifting platform 1. The powder scraping mechanism includes a movable seat 3 slidably fitted to a horizontal guide rail 31 on the machine body. The movable seat 3 is driven by a cylinder 2 to reciprocate along the horizontal guide rail 31. Specifically, the cylinder 2 is fixedly mounted on the machine body, and the output end of the cylinder 2 is fixedly connected to the side wall of the movable seat 3. A scraper box 4 is rotatably mounted on the movable seat 3 and can rotate about a vertical axis. A rotating tube 41 is provided on the top of the scraper box 4. A driving mechanism acts on the rotating tube 41 to drive the scraper box 4 as a whole to rotate about a vertical axis, which is the axis of the rotating tube 41. A scraper 5 is installed inside the scraper box 4, and its working surface changes orientation with the rotation of the scraper box 4, so that it always contacts the powder with its powder-facing surface during the forward or backward movement of the movable seat 3, avoiding back-flowing pushing and accumulation.

[0025] To achieve automatic switching between coarse and fine scraping, in another embodiment of the invention, the scraper 5 is rotatably connected to the scraper box 4 via a rotating shaft, and a torsion spring seat 51 is connected thereto, forming a lever structure. The axis of the rotating shaft is horizontal, specifically along the front-rear direction of the machine body. When one end of the scraper 5 rotates, the other end changes angle. A top post 6 is provided at the end of the scraper 5 away from the working surface. The top post 6 is slidably disposed in the aforementioned rotating tube 41 in a vertical direction. A spring 61 is provided between the top post 6 and the rotating tube 41 to provide preload. When the scraper box 4 rotates, the top post 6 moves up and down under the action of an external triggering mechanism, causing the scraper 5 to swing around the rotating shaft, overcoming the elastic force of the torsion spring seat 51, thereby automatically adjusting its tilt angle.

[0026] To reduce mechanical wear during long-term operation, in another embodiment of the present invention, the triggering mechanism adopts a magnetic coupling method: a first magnet 32 ​​is provided on the moving base 3 along the extension direction of the horizontal guide rail 31, with the left side region being the S pole and the right side region being the N pole. A second magnet 62 is provided on the top column 6. When the scraper box 4 rotates to the corresponding position, the second magnet 62 is displaced by the magnetic force of the different magnetic pole regions of the first magnet 32. This solution requires no physical contact and has low wear, but the nonlinearity of the magnetic force may cause slight fluctuations in angle adjustment. It is suitable for occasions with high requirements for response speed and strict cleanliness.

[0027] To achieve more continuous and stable scraper 5 angle adjustment, in another embodiment of the present invention, the triggering mechanism adopts a mechanical guiding method: the lower surface of the movable seat 3 is provided with a guide surface 33, and the top column 6 is provided with a protrusion 63. Under the pre-tensioning action of the spring 61, the protrusion 63 abuts upward against the guide surface 33. The guide surface 33 is an inclined curved surface, which can be referred to as... Figure 7The guide surface 33 is set as a spiral surface. When the scraper box 4 rotates, the protrusion 63 slides along the guide surface 33 to different heights, driving the top column 6 to move smoothly and realize the continuous adjustment of the scraper 5 angle. This method has good linearity of adjustment, but the machining accuracy and surface finish of the guide surface 33 must be ensured.

[0028] To further integrate the self-cleaning function, based on the above-described guide surface embodiment, and referring to... Figure 7 and Figure 8 The guide surface 33 is constructed as an annular curved surface, with a vertical drop section set in the rotation path. During normal powder scraping, the scraper box 4 reciprocates within the range of 90° to 270°; the protrusion 63 moves between the corresponding points a and b, and the top column 6 moves a distance m = L3 - L2. When cleaning is required, the cylinder 2 drives the moving seat 3 to move beyond its travel range, causing the scraper box 4 to complete a 360° rotation. When the protrusion 63 passes through the drop section, it suddenly moves upward, that is, when the protrusion 63 moves from point c to point d, the top column 6 moves a distance n = L4 - L1, with a huge drop. Under the release action of the spring 61, the scraper 5 undergoes a large-angle sudden change and vibration, shaking off the attached powder; at this time, the working surface of the scraper 5 faces the side away from the machine body to prevent powder from falling back and contaminating the area of ​​the lifting platform 1.

[0029] In one embodiment of the present invention, the driving mechanism is a motor, which is mounted on the movable base 3 and acts on the rotating tube 41 through transmission components such as gears or belts to drive the rotating tube 41 to rotate.

[0030] To simplify the drive system, in another embodiment of the invention, the drive mechanism includes two sets of racks 43, respectively disposed on the left and right sides of the horizontal guide rail 31 (i.e., on both sides along the width direction of the movable seat 3). The length of the racks 43 is slightly greater than half the stroke of the movable seat 3. A gear 42 is mounted on the rotating tube 41 via a one-way bearing. The locking direction of the one-way bearing is set such that the gear 42 is only allowed to drive the rotating tube 41 to rotate forward when the movable seat 3 moves to the right. When the movable seat 3 travels to the starting end of the rack 43 to the right, the gear 42 meshes with the right rack 43, driving the scraper box 4 to rotate 180°; during the return stroke, the gear 42 idles and does not reverse. A damping mechanism is disposed between the rotating tube 41 and the movable seat 3 to suppress shaking during the scraping process and ensure the stability of the scraper 5. The damping mechanism can specifically be configured as a damping bearing or a damping layer.

[0031] Based on the above structure, the present invention also provides a powder forming method. In this method, metal powder is first fed into a forming cavity formed by a lifting platform 1 and a mold; then, a moving seat 3 moves along a first direction, and a scraper 5 performs coarse scraping and leveling at a large angle and high speed; after reaching the end of the stroke, the scraper box 4 automatically rotates 180°, and at the same time, the lifting platform 1 activates its built-in vibration unit to apply vertical vibration of 15–30 Hz and 0.2–0.5 mm amplitude for 2–3 seconds to redistribute the powder particles; next, the moving seat 3 retracts along a second direction, and the scraper 5 performs fine scraping and shaping at a small angle and low speed; finally, the upper pressure head descends to press and form a green blank. If cleaning is required, an additional 360° rotation cleaning step can be performed.

[0032] Through the synergy of the above structures and methods, this invention achieves efficient, precise, and adaptive powder application, significantly improving green body quality and production efficiency.

[0033] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A powder forming device for powder metallurgy, comprising a machine body, a pressure head, and a lifting platform disposed directly below the pressure head, wherein a powder scraping mechanism is provided above the lifting platform, characterized in that, The powder scraping mechanism includes: A movable base is provided on the machine body, and the movable base is slidably fitted onto the horizontal guide rail. A scraper box, wherein a scraper is installed inside the scraper box, and the scraper box is rotatably mounted on a movable base and is capable of rotating about a vertical axis; A driving mechanism acts on the scraper box to drive the scraper box to rotate about a vertical axis so that the working surface of the scraper faces the current moving direction of the moving seat or its opposite direction.

2. The powder forming equipment for powder metallurgy according to claim 1, characterized in that, The movable seat is driven by a cylinder, and the output direction of the cylinder is parallel to the horizontal guide rail.

3. A powder forming device for powder metallurgy according to claim 1, characterized in that, The top of the scraper box is provided with a rotating tube, and the driving mechanism acts on the rotating tube to drive the scraper box to rotate around the vertical axis.

4. A powder forming device for powder metallurgy according to claim 3, characterized in that, The driving mechanism includes two sets of racks, which are respectively located on both sides of the horizontal guide rail; a gear is mounted on the rotating tube via a one-way bearing. When the moving seat drives the gear to move to the rack position, the gear meshes with the rack to drive the scraper box to rotate 180°; a damping mechanism is provided between the rotating tube and the moving seat.

5. A powder forming device for powder metallurgy according to claim 1 or 3, characterized in that, The scraper is rotatably connected to the scraper box via a rotating shaft in the middle and is connected to a torsion spring seat, so that the scraper forms a lever structure; a top post is provided at the end of the scraper away from the working surface, and the top post is slidably disposed in the rotating tube in the vertical direction; a spring is provided between the top post and the rotating tube.

6. A powder forming device for powder metallurgy according to claim 5, characterized in that, The movable seat is provided with a triggering mechanism, which is configured to act on the top column to change its vertical position in the rotating tube during the rotation of the scraper box around the vertical axis, thereby adjusting the tilt angle of the scraper.

7. A powder forming device for powder metallurgy according to claim 6, characterized in that, The triggering mechanism includes a first magnet and a second magnet; the first magnet is disposed on the movable seat and has a first magnetic pole region and a second magnetic pole region along the extension direction of the horizontal guide rail; the second magnet is disposed on the top column and its polarity matches that of the first magnet, so that when the rotating tube drives the top column to rotate to the position corresponding to the first magnetic pole region, the scraper is at a first tilt angle, and when it rotates to the position corresponding to the second magnetic pole region, the scraper is at a second tilt angle.

8. A powder forming device for powder metallurgy according to claim 6, characterized in that, The triggering mechanism includes a guide surface on the lower surface of the movable seat and a protrusion on the top column; under the preload of the spring, the protrusion abuts against the guide surface upward; the guide surface is an inclined curved surface, which is used to drive the top column to move in the vertical direction by changing the relative position of the protrusion and the guide surface during the rotation of the scraper box, thereby adjusting the angle of the scraper.

9. A powder forming device for powder metallurgy according to claim 8, characterized in that, The guide surface is an annular curved surface, which forms a first working height and a second working height at positions corresponding to the scraper box rotating 90° and 270°, respectively; the guide surface has a vertical drop section in the rotation path, when the scraper box rotates through this drop section, the protrusion suddenly moves upward due to loss of support, causing the scraper to produce a large angle change and vibration; wherein, when the scraper box completes a 360° rotation, the working surface of the scraper faces the side away from the machine body.

10. A powder forming method for powder metallurgy, implemented using the forming equipment described in any one of claims 1-9, characterized in that, Includes the following steps: Provide metal powder to the forming area; Move the scraper along the first direction to initially level the metal powder; At the end of the stroke, rotate the scraper so that the scraper's working surface faces a second direction opposite to the first direction; Vibration treatment of metal powder; Move the scraper along the second direction to scrape the metal powder again; Metal powder is pressed to form a blank.

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