Metal powder additive manufacturing near-net shape forging device and forging process

Abstract

The application discloses a metal powder additive manufacturing near-net-shape forging device and a forging process, and belongs to the technical field of metal powder additive manufacturing. The device comprises a lower die and an upper die, a forming assembly arranged on the lower die and the upper die, a clamping assembly and a retreat assembly arranged on the lower die, a triggering assembly arranged on the lower die and the upper die, and a floating assembly arranged on the upper die. The additive blank is clamped and positioned before forging forming, the additive blank is limited from tilting and deviating in the die cavity, and the additive blank is pre-pressed and fixed before the forging part contacts the additive blank, so that the position deviation of the additive blank with complex shape and low size consistency during die loading and the initial forging stage is improved, the additive blank is ensured to be deformed under pressure according to the predetermined position, and the forming precision and the internal compactness of the forged piece are improved.

Description

Technical Field

[0001] This invention belongs to the field of metal powder additive manufacturing technology, specifically relating to a near-net-shape forging device and forging process for metal powder additive manufacturing. Background Technology

[0002] Metal powder additive manufacturing technology uses heat sources such as lasers to melt metal powder layer by layer along a preset path to form a blank that closely resembles the shape of the target part. It is suitable for manufacturing metal parts with complex internal structures and high material utilization requirements. After the blank is completed in additive manufacturing, it can be transferred to the forging station while maintaining a high temperature. The clamping structure places it in the forming area of ​​the lower die, and the upper die moves toward the lower die and applies pressure to the blank, causing the internal pores of the blank to close, improving the internal structure, and correcting the external contour.

[0003] Because the surface of additively formed blanks is relatively rough and there are local protrusions on the outer contour, there will also be a deviation between the center of gravity and the geometric center of the blank. The clamping structure needs to restrict the position of the blank before forging and exit the forming area before the forging die closes. If the clamping structure is released too early, the blank is not yet constrained by the die and will shift or tilt under its own weight, transfer inertia or die contact force, resulting in uneven distribution of forging allowance in various parts. If the clamping structure is released too late, the clamping part will be squeezed by the upper die or the blank, which will not only hinder the die closing but also leave indentations on the blank surface. Existing technologies usually use robotic grippers to directly place the blank and then control the grippers to open and move out of the die before the upper die descends, or use independent hydraulic cylinders to drive the clamping parts to retract. Using robotic grippers relies on the preset action time and cannot determine the clamping release position according to the actual state of the blank constrained by the die. Using independent hydraulic cylinders requires the setting of drive elements, control valves and detection elements, which occupies a large space and increases maintenance work in the high-temperature forging environment. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a near-net-shape forging apparatus and forging process for metal powder additive manufacturing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A near-net-shape forging apparatus for metal powder additive manufacturing includes a lower die and an upper die, a forming component disposed on the lower die and the upper die, a clamping component and a retraction component disposed on the lower die, a triggering component disposed on the lower die and the upper die, and a floating component disposed on the upper die. The forming component includes a first cavity formed on the lower die, and a forging part is disposed on the upper die. The clamping assembly includes two first blocks, each of which is provided with a plate. The triggering component includes a trigger element disposed on the upper mold; The floating component includes a ring body slidably disposed on the upper mold, the ring body being arranged around the forging part; When the upper die approaches the lower die, the ring body preferentially presses against the blank and reaches a preset pre-compression state. After the ring body reaches the preset pre-compression state, the triggering element drives the two first blocks away from the first cavity and keeps the two plates outside the movement range of the forging part.

[0006] Preferably, the lower mold has first grooves on opposite sides of the first cavity, and the two first blocks are slidably disposed in the two first grooves, with the first grooves extending along a path close to or away from the first cavity.

[0007] Preferably, each plate is rotatably disposed on the side of the corresponding first block near the first cavity, a first elastic element is provided between the plate and the corresponding first block, and at least two contact portions for pressing against the blank are provided on the side of the plate facing the first cavity.

[0008] Preferably, each plate is provided with a rod that is offset from its rotation center, and the lower mold is provided with a second block corresponding to the rod. When the first block moves away from the first cavity, the second block blocks the rod, so that the rod drives the plate to rotate and gradually detach from the blank.

[0009] Preferably, the retraction assembly includes a first engagement member and a second engagement member respectively connected to the two first blocks, and the lower mold is rotatably provided with a third engagement member. The opposite sides of the third engagement member engage with the first engagement member and the second engagement member respectively, so that the two first blocks move closer to each other or further away from each other synchronously.

[0010] Preferably, a second elastic element is provided between the third engaging member and the lower mold. When the two first blocks are far away from the first cavity, the third engaging member causes the second elastic element to store elastic force. After the triggering member releases the restriction on the first blocks, the second elastic element drives the two first blocks to move closer to each other through the third engaging member.

[0011] Preferably, one of the first blocks is provided with a third block, the third block having an inclined portion that cooperates with the trigger, the inclined portion being inclined along the path of the upper mold approaching the lower mold, so as to convert the movement of the trigger into the movement of the first block away from the first cavity.

[0012] Preferably, the third block also has a retaining portion connected to the inclined portion, the retaining portion extending along the path of the upper mold toward or away from the lower mold, and when the trigger cooperates with the retaining portion, the two first blocks are held in a position away from the first cavity.

[0013] Preferably, the upper die has a second groove surrounding the forging part, the ring body is slidably disposed in the second groove, a third elastic element is provided between the ring body and the bottom of the second groove, and the ring body has a limiting part that cooperates with the bottom of the second groove, the limiting part being used to limit the distance the ring body enters the second groove.

[0014] This invention also discloses a near-net-shape forging process for metal powder additive manufacturing, comprising the following steps: Step 1: Establish an additive blank model based on the shape of the target part, and set material compensation parts in the additive blank model at the corners, thin walls or cross-sectional changes of the target part. Step 2: Using metal powder, the additive blank is formed layer by layer according to the additive blank model to obtain an additive blank with the material compensation part. The additive blank is then subjected to powder removal, support removal and stress relief treatment. Step 3: Heat the additive blank and load the heated additive blank into the first cavity of the lower mold, and clamp the additive blank with the plates located on both sides of the first cavity; Step 4: Drive the upper die closer to the lower die, so that the ring body surrounding the forging part presses against the additive blank before the forging part; Step 5: After the ring body presses against the additive blank and reaches the preset pre-compression state, the trigger element that moves with the upper die drives the two first blocks to move away from each other, so that the two plates are separated from the additive blank and exit the movement range of the forging part. Step 6: Continue to drive the upper die closer to the lower die, so that the forging part and the first cavity jointly extrude the additive billet, and the metal material of the material compensation part flows to the corresponding forming part to obtain a near-net-shape forging; Step 7: After the forging part is withdrawn, the ring body separates the near-net-shape forging from the forging part, the upper die continues to move away from the lower die, the triggering element releases the restriction on the third block, and the second elastic element drives the two first blocks to reset through the third engaging element; Step 8: Remove the near-net-shape forging and perform cooling, surface cleaning, machining and heat treatment on the near-net-shape forging.

[0015] The beneficial effects of this invention are as follows: I. In this invention, by clamping and positioning the additive billet before forging, the tilting and displacement of the additive billet within the die cavity are restricted. The billet is pre-pressed and fixed before the forging part contacts it. As the upper die approaches the lower die, the clamping action is automatically released, and the clamping part simultaneously exits the movement range of the forging part and remains in a yielding state. This ensures that the additive billet remains stable even after losing lateral clamping, avoiding interference between the clamping structure and the forging part. This improves the positional deviation of additive billets with complex shapes and low dimensional consistency during die loading and the initial forging stage, ensuring that the additive billet is compressed and deformed according to a predetermined position. This allows the metal material to flow more accurately to complex corners, thin walls, and cross-sectional change areas, improving the forming accuracy and internal density of the forging.

[0016] Second, in this invention, the contact state can be automatically adjusted according to the slope of the side of the additive blank and the local dimensional differences. During the retraction process, the clamping part gradually separates from the high-temperature blank, reducing the retraction resistance caused by adhesion. When the upper mold is reset, it continuously presses against the forging, so that the forging is reliably separated from the forging part. After the forging part is withdrawn, the clamping effect is automatically restored. The entire clamping, pre-pressing, retraction, pressure holding demolding and reset process is completed by the lifting and lowering movement of the upper mold, which is beneficial to improving the continuity and stability of the device operation and reducing manual adjustment operations. Attached Figure Description

[0017] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the present invention; Figure 2 This is a three-dimensional schematic diagram of the overall structure of the present invention from another perspective; Figure 3 This is a three-dimensional schematic diagram of the upper and lower mold structures of the present invention; Figure 4 This is a three-dimensional schematic diagram of the lower mold and its surface structure of the present invention; Figure 5 This is a three-dimensional schematic diagram of the first block and its surface structure of the present invention; Figure 6 This is a schematic diagram of the rod body and the second block structure of the present invention; Figure 7 This is a three-dimensional schematic diagram of the second elastic element structure of the present invention; Figure 8 This is a three-dimensional schematic diagram of the third block and trigger structure of the present invention; Figure 9 This is a three-dimensional schematic diagram of the second tank structure of the present invention; Figure 10 This is a three-dimensional schematic diagram of the ring structure of the present invention.

[0018] In the diagram: 1. Lower mold; 2. Upper mold; 3. Forming assembly; 31. First cavity; 32. First groove; 33. Forging part; 4. Clamping assembly; 41. First block; 42. Plate; 421. Contact part; 43. First elastic element; 44. Rod; 45. Second block; 5. Retraction assembly; 51. First engaging element; 52. Second engaging element; 53. Third engaging element; 54. Second elastic element; 6. Trigger assembly; 61. Third block; 611. Inclined part; 612. Holding part; 62. Trigger element; 7. Floating assembly; 71. Second groove; 72. Ring; 721. Limiting part; 73. Third elastic element. Detailed Implementation

[0019] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0020] Please see Figure 1 A near-net-shape forging apparatus for metal powder additive manufacturing includes a lower die 1, an upper die 2, a forming component 3, a clamping component 4, a retraction component 5, a triggering component 6, and a floating component 7. The lower die 1 is connected to the fixed end of a forging equipment, and the upper die 2 is connected to the movable end of the forging equipment. The upper die 2 can move closer to or further away from the lower die 1 under the drive of the forging equipment. The forming component 3 is disposed between the lower die 1 and the upper die 2. The clamping component 4 is disposed between the lower die 1. The retraction component 5 is disposed between the clamping components 4. The triggering component 6 is disposed between the upper die 2 and the clamping components 4. The floating component 7 is disposed between the upper die 2. The forming component 3 is used to forge the billet formed by additive manufacturing. The clamping component 4 is used to limit the position of the billet. The retraction component 5 is used to make the clamping component 4 retract or reset synchronously. The triggering component 6 is used to drive the clamping component 4 to retract by the movement of the upper die 2. The floating component 7 is used to clamp the billet before forging and to separate the forging from the upper die 2 during the return stroke of the upper die 2.

[0021] It should be noted that, in combination Figure 1 The lower die 1 and the upper die 2 are set opposite to each other. When the upper die 2 approaches the lower die 1, it completes the pre-pressing, clamping and retraction of the billet and the forging. When the upper die 2 moves away from the lower die 1, it completes the return pressing and clamping reset. The forging equipment can be a hydraulic press, a mechanical press or existing equipment that can drive the upper die 2 to move linearly back and forth.

[0022] like Figure 2 As shown, the first cavity 31 in the forming assembly 3 is opened on the surface of the lower die 1 facing the upper die 2. The contour of the first cavity 31 is adapted to the target shape of the blank near the lower die 1. The first cavity 31 is used to accommodate the heated additive blank and restrict the flow of metal material near the lower die 1 during the forging process. Two first grooves 32 are provided, such as... Figure 3As shown, two first grooves 32 are both formed on the lower mold 1 and are located on both sides of the first cavity 31. Both first grooves 32 are elongated. One end of the first groove 32 is close to the first cavity 31, and the other end is away from the first cavity 31. The first groove 32 is used to accommodate and guide the movement of the clamping assembly 4. The forging part 33 is fixedly set on the side of the upper mold 2 facing the lower mold 1. The forging part 33 is opposite to the first cavity 31. The forming surface of the forging part 33 is adapted to the target shape of the blank on the side away from the lower mold 1. When the upper mold 2 approaches the lower mold 1, the forging part 33 approaches the first cavity 31 along with the upper mold 2. After the forging part 33 contacts the blank, the forging part 33 and the first cavity 31 jointly squeeze the blank to form a predetermined shape.

[0023] like Figure 4 As shown, the clamping assembly 4 has two first blocks 41, which are slidably disposed within two first grooves 32. Each first block 41 is block-shaped and conforms to the shape of the first groove 32. The two groove walls of the first groove 32 restrict the lateral displacement of the first block 41, allowing it to move closer to or further away from the first cavity 31 along the first groove 32. Each first block 41 has a clamping end close to the first cavity 31 and a driving end away from the first cavity 31. When the two first blocks 41 approach each other, the two clamping ends approach the first cavity 31 and clamp the blank. When the two first blocks 41 move away from each other, the two clamping ends retract from the forging section 33. When the first block 41 passes through the area near the first cavity 31, even when the first block 41 is in its maximum retraction position, a portion of the first block 41 is still located within the first groove 32, allowing the first groove 32 to continue supporting and guiding the first block 41. When the first block 41 is in its reset position, the clamping end of the first block 41 is restricted by the end of the first groove 32 near the first cavity 31, thereby limiting the reset position of the first block 41. One of the two first blocks 41 is the active first block 41, and the other is the passive first block 41. The active first block 41 cooperates with the trigger component 6, and the passive first block 41 moves with the active first block 41 through the retraction component 5.

[0024] like Figure 4As shown, two plates 42 are provided, each rotatably mounted on the side of the two first blocks 41 near the first cavity 31, allowing the plates 42 to rotate at a small angle relative to the first blocks 41. A rotational gap is left between the surface of the plates 42 facing the first blocks 41 and the first blocks 41. The surfaces of the two plates 42 facing the first cavity 31 serve as clamping surfaces. After the billet enters between the two plates 42, the two plates 42 press against the sides of the billet. When there is a slope or local dimensional difference on the side of the billet, the plates 42 can adjust the position according to the billet's dimensions. The tilt of the material side rotates automatically to adapt the clamping surface to the side of the blank. Each plate 42 is provided with two contact parts 421 on the side near the first cavity 31. The two contact parts 421 are symmetrically arranged and are elongated. The contact parts 421 are fixedly connected to the plate 42. The contact parts 421 are preferably integrally formed with the plate 42. The surface of the contact parts 421 facing the blank is arc-shaped to reduce local indentations formed when clamping the blank. The two contact parts 421 press against different parts of the side of the blank, thereby limiting the tilt of the blank.

[0025] like Figure 5 As shown, the first elastic element 43 is disposed between the plate 42 and the first block 41. The first elastic element 43 is preferably a torsion spring. One end of the first elastic element 43 abuts against the first block 41 and the other end abuts against the plate 42. When the plate 42 is in the center position, the first elastic element 43 is kept pre-tight. When the plate 42 is pushed by the blank and rotates, the first elastic element 43 applies a rotational force to the plate 42, so that the plate 42 keeps pressing against the blank. After the blank releases the restriction on the plate 42, the first elastic element 43 drives the plate 42 back to the center position.

[0026] like Figure 6As shown, rod 44 is disposed on the side of each plate 42 away from the first cavity 31. One end of rod 44 is fixedly connected to plate 42. The connection position between rod 44 and plate 42 is offset from the rotation center of plate 42. When rod 44 is blocked, rod 44 transmits rotational force to plate 42. Two second blocks 45 are disposed, and the two second blocks 45 are fixed to the lower mold 1 respectively. Each second block 45 corresponds to one rod 44. The second block 45 is located within the path that rod 44 takes when it moves away from the first cavity 31 along with the first block 41. The end of rod 44 away from plate 42 is located within the height range of the blank held by plate 42. The blocking surface of second block 45 is located at the height position corresponding to rod 44. There is an initial gap between rod 44 and second block 45. The initial gap is less than the first block 41 clearance distance required for contact part 421 to completely detach from the blank, so that the first block 41 begins to move away from the first cavity 31. After 1, the rod 44 can contact the second block 45 before the contact part 421 completely detaches from the billet, and limit the speed at which the first block 41 continues to move away from the first cavity 31. When the first block 41 is in the clamping position, there is a gap between the rod 44 and the second block 45, so that the plate 42 can deflect on its own according to the side of the billet. After the first block 41 moves away from the first cavity 31 to a certain distance, the rod 44 contacts the second block 45. When the first block 41 continues to move, the second block 45 blocks the end of the rod 44 that is away from the plate 42, so that the rod 44 drives the plate 42 to rotate under the blocking action, so that one side of the contact part 421 leaves the billet first, and the rest leaves the billet subsequently. The contact part 421 is thus gradually peeled off from the surface of the high-temperature billet, reducing the yielding resistance caused by the adhesion between the contact part 421 and the billet. After the contact part 421 detaches from the billet, the plate 42 continues to yield with the first block 41 until it completely exits the moving area of ​​the forging part 33.

[0027] like Figure 4As shown, the first meshing member 51 and the second meshing member 52 in the retraction assembly 5 are preferably spur racks. The first meshing member 51 is fixed to the driving first block 41, and the second meshing member 52 is fixed to the driven first block 41. The first meshing member 51 and the second meshing member 52 move synchronously with their respective first blocks 41. The first meshing member 51 and the second meshing member 52 are arranged parallel to each other, and the tooth surface of the first meshing member 51 is opposite to the tooth surface of the second meshing member 52. The third meshing member 53 is preferably a cylindrical gear. The third meshing member 53 is rotatably disposed on the lower mold 1 and located between the first meshing member 51 and the second meshing member 52. One side of the third meshing member 53 meshes with the first meshing member 51, and the other side meshes with the second meshing member 52. When the first engaging member 51 moves with the active first block 41, the first engaging member 51 drives the third engaging member 53 to rotate. The third engaging member 53 pushes the second engaging member 52 to move to the opposite side, so that the two first blocks 41 move away from each other or move closer to each other synchronously. Four limiting blocks are fixedly provided on the lower mold 1. The four limiting blocks are located at both ends of the movement path of the first engaging member 51 and the second engaging member 52 respectively. When the first engaging member 51 or the second engaging member 52 moves to the end of the corresponding stroke, it abuts against the corresponding limiting block, and still maintains the engagement length with the third engaging member 53, so as to limit the first engaging member 51 and the second engaging member 52 from exceeding the predetermined stroke and prevent the first engaging member 51 and the second engaging member 52 from disengaging from the third engaging member 53.

[0028] It should be noted that, in combination Figure 6 The first meshing member 51 and the second meshing member 52 have the same tooth pitch. The third meshing member 53 meshes with the first meshing member 51 and the second meshing member 52 simultaneously. Therefore, the moving distance of the active first block 41 and the driven first block 41 is the same. The two plates 42 can move away from the opposite sides of the blank at the same time, avoiding the blank being pushed by one side. The effective tooth segment length of the first meshing member 51 and the second meshing member 52 is greater than the distance that the first block 41 moves from the clamping position to the maximum retraction position, so that each meshing member remains engaged during the retraction process.

[0029] like Figure 7 As shown, the second elastic element 54 is preferably a torsion spring. The wound portion of the second elastic element 54 is sleeved at the rotation center of the third engaging element 53. One end of the second elastic element 54 is connected to the lower mold 1, and the other end is connected to the third engaging element 53. When the two first blocks 41 are in the clamping position, the second elastic element 54 is kept pre-tight. When the active first block 41 retracts, the first engaging element 51 drives the third engaging element 53 to rotate. The third engaging element 53 twists the second elastic element 54, so that the second elastic element 54 stores elastic force. After the trigger component 6 releases the restriction, the second elastic element 54 drives the third engaging element 53 to rotate in the opposite direction, so that the first engaging element 51 and the second engaging element 52 drive the two first blocks 41 to reset synchronously.

[0030] like Figure 5 As shown, the third block 61 in the trigger assembly 6 is fixed to the top side of the active first block 41. The third block 61 has an inclined portion 611 and a retaining portion 612. The inclined portion 611 is formed on the surface of the third block 61 facing the upper mold 2. The inclined portion 611 is an inclined surface. The inclined portion 611 gradually approaches the upper mold 2 from the end closer to the first cavity 31 to the end farther away from the first cavity 31. Figure 8 As shown, the holding part 612 is formed at one end of the inclined part 611 near the first cavity 31. The holding part 612 extends along the moving path of the upper mold 2 when it approaches or moves away from the lower mold 1, and is perpendicular to the moving path of the active first block 41. The inclined part 611 and the holding part 612 are smoothly connected by an arc surface. The trigger member 62 is rod-shaped. One end of the trigger member 62 is fixed to the upper mold 2, and the other end extends toward the lower mold 1. The end of the trigger member 62 near the lower mold 1 forms an arc contact surface. The position of the trigger member 62 corresponds to that of the inclined part 611.

[0031] When using, combine Figure 5 and Figure 8 When the upper mold 2 approaches the lower mold 1, the trigger 62 contacts the inclined portion 611. As the trigger 62 continues to move, the inclined portion 611 converts the pressure applied by the trigger 62 into a force that pushes the active first block 41 away from the first cavity 31. The active first block 41 drives the driven first block 41 to retract synchronously through the retraction component 5. When the active first block 41 reaches the maximum retraction position, the trigger 62 moves to the connection position between the inclined portion 611 and the holding portion 612. As the upper mold 2 continues to approach the lower mold 1, the trigger 62 transitions from the inclined portion 611 to the holding portion 612. The holding portion 612 restricts the third block 61 from approaching the first cavity 31, keeping the two first blocks 41 in the maximum retraction position. When the trigger 62 moves along the holding portion 612, it no longer pushes the third block 61 to continue retracting, thereby preventing the first block 41 from exceeding the allowable movement distance of the first groove 32.

[0032] like Figure 9 As shown, the second groove 71 in the floating assembly 7 is formed on the surface of the upper die 2 facing the lower die 1. The second groove 71 is a closed ring surrounding the forging part 33. The ring 72 is slidably disposed in the second groove 71. The two groove walls of the second groove 71 are respectively slidably engaged with the surfaces of the ring 72 near and away from the forging part 33, so that the ring 72 can only move along the path of the upper die 2 towards or away from the lower die 1. When the ring 72 is in the freely extended state, the surface of the ring 72 facing the lower die 1 is closer to the lower die 1 than the forming surface of the forging part 33, so that the ring 72 contacts the blank before the forging part 33. The contour of the side of the ring 72 away from the forging part 33 is located between the two plates 42. When the ring 72 is close to the blank, it does not contact the plates 42 and the contact part 421. Figure 10As shown, four third elastic elements 73 are provided. The third elastic elements 73 are preferably compression springs. The four third elastic elements 73 are evenly spaced along the extension path of the ring body 72. One end of each third elastic element 73 abuts against the bottom of the second groove 71, and the other end abuts against the ring body 72. When the ring body 72 enters the second groove 71, the four third elastic elements 73 are compressed at the same time and apply a uniformly distributed elastic force to the ring body 72.

[0033] like Figure 10 As shown, the limiting part 721 is formed on the surface of the ring body 72 near the bottom of the second groove 71. The limiting part 721 is in the shape of annular steps. When the ring body 72 is in the free extension state, there is a pre-compression movement distance between the limiting part 721 and the bottom of the second groove 71. After the limiting part 721 abuts against the bottom of the second groove 71, the ring body 72 cannot continue to enter the second groove 71. The third elastic member 73 still retains the compression space in this state and transmits the forging load to the upper die 2 through the limiting part 721.

[0034] This embodiment also discloses a near-net-shape forging process for metal powder additive manufacturing implemented using the above-mentioned device. The process includes additive billet design, metal powder additive forming, additive billet processing, billet heating, mold preparation, billet loading, floating pre-pressing, clamping and retraction, forging, return pressing, billet removal and post-processing. When designing the additive blank, a part model is established based on the target shape of the forged part, and the part model is adjusted according to the flow path of the metal material during the forging process to form an additive blank model. The additive blank model retains machining allowances at the parts close to the main forming surfaces of the first cavity 31 and the forging part 33. Material compensation parts are set at the positions corresponding to complex corners, thinner parts and parts with cross-sectional changes. The material compensation parts are continuously connected to the additive blank body and are used to supplement metal material to the parts that are difficult to fill during the forging process. The total volume of the additive blank is determined based on the forming space formed after the first cavity 31 and the forging part 33 are closed. More metal material is retained in complex corners, thinner parts and parts with cross-sectional changes, while the remaining surfaces retain the machining allowance required for machining, thereby ensuring that the forming space is fully filled and reducing the amount of material removed after forging. When performing metal powder additive manufacturing, metal powder is added to the additive manufacturing equipment. The additive manufacturing equipment lays up the metal powder layer by layer according to the additive blank model, and selectively melts each layer of metal powder with an energy beam, so that adjacent melted layers are connected to each other to form a near-net-shape blank. The energy beam is preferably a laser beam or an electron beam. The additive manufacturing process is preferably carried out in an inert gas protective environment or a vacuum environment. In this embodiment, titanium alloy powder is preferably used as the metal powder. The main outline of the billet is adapted to the first cavity 31. The outline size of the billet is smaller than the outline size of the corresponding position of the first cavity 31, so that the heated billet can be put into the first cavity 31. It should be noted that the metal powder can also be aluminum alloy powder, high temperature alloy powder, stainless steel powder or other metal powders that can be used for additive manufacturing and plastic forging, depending on the requirements of the target part. When changing the metal powder material, the billet heating temperature, the mold preheating temperature and the moving speed of the upper mold 2 should be adjusted according to the plastic deformation temperature of the material. After the metal powder additive forming is completed, the blank is separated from the additive manufacturing substrate, and the unmelted metal powder remaining on the surface of the blank and at the opening of the pores is removed. If the blank has an additive manufacturing support structure, the support structure is removed and the connection position of the support structure is adjusted so that there are no protruding parts on the outer surface of the blank that would hinder the blank from being loaded into the first cavity 31. After the powder is removed, the billet is subjected to stress relief heat treatment to reduce the residual stress generated by the layer-by-layer additive forming. After the stress relief heat treatment is completed, the surface of the billet is inspected and loose attachments and sharp protrusions on the surface of the billet are removed. Before forging, the first cavity 31, forging part 33, ring 72 and contact part 421 are cleaned, and a forging lubricant compatible with the billet material is applied to the forming surfaces of the first cavity 31 and forging part 33. After cleaning, the lower die 1 and upper die 2 are preheated. When heating the billet, the processed additive billet is heated to the forging temperature of the corresponding metal material and held at that temperature so that the inside and outside of the billet reach a temperature state suitable for plastic deformation. In this embodiment, when using titanium alloy additive billet, the billet is preferably heated to 900 to 950 degrees Celsius, and the lower die 1 and upper die 2 are preferably preheated to 250 to 350 degrees Celsius. After the billet has been held at that temperature, it is transferred to the first cavity 31 and the transfer time is limited so that the billet is still within the set forging temperature range when it is loaded into the first cavity 31.

[0035] The following describes the working principle of the device in this embodiment in conjunction with the forging process: When preparing to use, combine Figures 1 to 10The upper mold 2 is located away from the lower mold 1. The trigger 62 is separated from the third block 61. The second elastic member 54 drives the first meshing member 51 and the second meshing member 52 to move closer to each other through the third meshing member 53, so that the two first blocks 41 are kept in the reset position. The two plates 42 are located on opposite sides of the first cavity 31. When loading the blank, the heated additive blank is placed into the first cavity 31. The blank enters between the two plates 42 and pushes the two plates 42 and the two first blocks 41 to move away from each other. The second elastic member 54 applies a force to the two first blocks 41 to move closer to each other through the yielding component 5, so that the two plates 42 press against the opposite sides of the blank respectively. When there is a slope or local size difference on the side of the blank, the plate 42 rotates according to the degree of inclination of the side of the blank. The two contact parts 421 press against different parts of the side of the blank respectively. The first elastic member 43 keeps the plate 42 pressing against the blank, thereby limiting the inclination or displacement of the blank in the first cavity 31. When performing floating preloading, combine Figures 5 to 10The forging equipment moves the upper die 2 closer to the lower die 1. The ring 72 contacts the blank before the forging part 33. As the upper die 2 continues to move, the blank blocks the ring 72. The ring 72 enters the second groove 71 and compresses the third elastic element 73. The third elastic element 73 presses the blank against the first cavity 31 through the ring 72. The ring 72 enters the second groove 71 and compresses the third elastic element 73 until the third elastic element 73 reaches the preset compression amount. The third elastic element 73 presses the blank against the first cavity 31 through the ring 72, forming a preset preload. Before the third elastic element 73 reaches the preset compression amount, the trigger 62 maintains a gap with the inclined part 611. At this time, the trigger 62 has not yet contacted the inclined part 611. The two plates 42 continue to clamp the blank, and the ring 72 forms... After pre-compression, the trigger 62 contacts the inclined portion 611. An initial distance exists between the contact surface of the trigger 62 near the lower die 1 and the surface of the ring 72 facing the lower die 1. This initial distance corresponds to the distance the upper die 2 needs to move to compress the third elastic element 73 and form a preset pre-compression after the ring 72 contacts the blank. During the process of the ring 72 contacting the blank and compressing the third elastic element 73, the trigger 62 maintains a gap with the inclined portion 611. Only after the third elastic element 73 reaches a preset compression amount and the ring 72 forms a preset pre-compression on the blank does the trigger 62 contact the inclined portion 611 and drive the third block 61 to move. Subsequently, the upper die 2 continues to approach the lower die 1, and the trigger 62 pushes the third block 61 away from the first cavity 31 through the inclined portion 611. Body 61 drives the active first block 41 to move. The active first block 41 drives the third meshing member 53 to rotate through the first meshing member 51. The third meshing member 53 pushes the second meshing member 52 to move to the opposite side, so that the driven first block 41 and the active first block 41 move away from the first cavity 31 synchronously. When the third meshing member 53 rotates, it twists the second elastic member 54, so that the second elastic member 54 stores elastic force. After the two first blocks 41 have moved back a certain distance, the rod 44 contacts the second block 45. When the first block 41 continues to move, the second block 45 blocks the end of the rod 44 away from the plate 42. The rod 44 drives the plate 42 to rotate, so that one side of the contact part 421 leaves the blank first, and the rest gradually leaves the blank as the plate 42 rotates. The material is pushed away, causing the contact part 421 to peel off from the surface of the high-temperature blank. After the contact part 421 is completely separated from the blank, the plate 42 continues to retract with the first block 41. During this process, the ring 72 continuously presses against the blank to prevent the blank from moving with the plate 42. When the trigger 62 moves to the holding part 612, the two first blocks 41 reach the maximum retraction position. The two plates 42 and the contact part 421 exit the area that the forging part 33 passed through when it approached the first cavity 31. When the upper die 2 continues to approach the lower die 1, the trigger 62 moves along the holding part 612. The holding part 612 restricts the active first block 41 from resetting. The retraction assembly 5 keeps the driven first block 41 in the corresponding retraction position, thereby avoiding interference between the plate 42 and the contact part 421 and the forging part 33. During forging and forming, combined Figure 9 and Figure 10 The upper die 2 continues to approach the lower die 1, and the ring 72 continues to enter the second groove 71 until the limiting part 721 abuts against the bottom of the second groove 71. The forging part 33 then contacts the billet and, together with the first cavity 31, squeezes the billet, causing the metal material in the billet to flow from the material compensation part and the part with more material to the complex corner, the thinner part and the part that is not fully filled. Under the action of forging pressure, the pores inside the additive billet are compressed, and the metal material on both sides of the pores moves closer to each other. The interlayer bonding area is squeezed and plastic deformation occurs, making the internal structure of the billet gradually denser. After the forging part 33 reaches the set position, the forging equipment keeps the upper die 2 for a predetermined time, so that the billet is continuously pressed and fully fills the forming space between the first cavity 31 and the forging part 33, forming a forging that is close to the shape of the target part. After forging and holding pressure are completed, combined Figures 4 to 10 The forging equipment moves the upper die 2 away from the lower die 1. The trigger 62 moves along the holding part 612 first. The holding part 612 continues to restrict the active first block 41 from resetting, keeping the two plates 42 in the maximum retraction position. When the forging part 33 leaves the forging, the third elastic element 73 releases its elastic force and pushes the ring 72 out of the second groove 71. The ring 72 continues to press the forging against the first cavity 31, separating the forging from the forging part 33 and preventing the forging from adhering to the forging part 33 and moving with the upper die 2. The upper die 2 continues to move away from the lower die 1. After the ring 72 leaves the forging, the trigger 62 still... The retaining part 612 contacts, keeping the two plates 42 retracted before the forging part 33 and the ring 72 leave the corresponding area. After the trigger 62 moves to the connection position between the retaining part 612 and the tilting part 611, the retaining part 612 gradually releases the restriction on the third block 61. The second elastic member 54 releases the elastic force and drives the third engaging member 53 to rotate in the opposite direction. The third engaging member 53 drives the two first blocks 41 to move towards the first cavity 31 synchronously through the first engaging member 51 and the second engaging member 52. The tilting part 611 cooperates with the trigger 62 and guides the two first blocks 41 to return to their original position smoothly. When the two first blocks 41 are reset, they combine Figure 5 and Figure 6 As the rod 44 gradually moves away from the second block 45, the second block 45 releases its obstruction of the rod 44. The first elastic element 43 drives the plate 42 back to the center position. After the trigger 62 leaves the inclined part 611, the two first blocks 41 return to the reset position. The two plates 42 restrict the forging from the opposite sides of the forging. After the forging is removed, the second elastic element 54 keeps the two first blocks 41 in the unloaded reset position. After the forging is removed, it is slowly cooled or cooled according to the heat treatment requirements of the corresponding metal material. After cooling, the lubricant and oxides on the surface of the forging are removed, and the external dimensions, surface integrity and internal density of the forging are checked. After the inspection is completed, the machining allowance on the surface of the forging is machined, and solution treatment, aging or annealing treatment is performed according to the material and performance requirements of the forging to obtain metal parts that meet the target shape and microstructure requirements.

[0036] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A near-net-shape forging apparatus for metal powder additive manufacturing, comprising a lower die (1) and an upper die (2), a forming component (3) disposed on the lower die (1) and the upper die (2), a clamping component (4) and a retraction component (5) disposed on the lower die (1), a triggering component (6) disposed on the lower die (1) and the upper die (2), and a floating component (7) disposed on the upper die (2), characterized in that: The forming component (3) includes a first cavity (31) formed on the lower mold (1) and a forging part (33) provided on the upper mold (2). The clamping assembly (4) includes two first blocks (41), each of which is provided with a plate (42). The triggering component (6) includes a trigger element (62) disposed on the upper mold (2); The floating component (7) includes a ring (72) slidably disposed on the upper mold (2), the ring (72) being arranged around the forging part (33); When the upper die (2) approaches the lower die (1), the ring (72) presses against the blank and reaches a preset pre-press state. After the ring (72) reaches the preset pre-press state, the trigger (62) drives the two first blocks (41) away from the first cavity (31) and keeps the two plates (42) outside the movement range of the forging part (33).

2. The near-net-shape forging apparatus for metal powder additive manufacturing according to claim 1, characterized in that: The lower mold (1) has first grooves (32) on opposite sides of the first cavity (31), and the two first blocks (41) are slidably disposed in the two first grooves (32), with the first grooves (32) extending along a path close to or away from the first cavity (31).

3. The near-net-shape forging apparatus for metal powder additive manufacturing according to claim 1, characterized in that: Each of the plates (42) is rotatably disposed on the side of the corresponding first block (41) near the first cavity (31). A first elastic element (43) is provided between the plate (42) and the corresponding first block (41). The plate (42) facing the first cavity (31) is provided with at least two contact portions (421) for pressing against the blank.

4. The near-net-shape forging apparatus for metal powder additive manufacturing according to claim 1, characterized in that: Each plate (42) is provided with a rod (44) that is offset from its rotation center. The lower mold (1) is provided with a second block (45) corresponding to the rod (44). When the first block (41) moves away from the first cavity (31), the second block (45) blocks the rod (44) so ​​that the rod (44) drives the plate (42) to rotate and gradually detach from the blank.

5. The near-net-shape forging apparatus for metal powder additive manufacturing according to claim 1, characterized in that: The retraction component (5) includes a first engagement member (51) and a second engagement member (52) respectively connected to the two first blocks (41). The lower mold (1) is rotatably provided with a third engagement member (53). The opposite sides of the third engagement member (53) engage with the first engagement member (51) and the second engagement member (52) respectively, so that the two first blocks (41) move closer to each other or further away from each other synchronously.

6. The near-net-shape forging apparatus for metal powder additive manufacturing according to claim 5, characterized in that: A second elastic element (54) is provided between the third engaging member (53) and the lower mold (1). When the two first blocks (41) move away from the first cavity (31), the third engaging member (53) causes the second elastic element (54) to store elastic force. After the trigger (62) releases the restriction on the first block (41), the second elastic element (54) drives the two first blocks (41) to move closer to each other through the third engaging member (53).

7. The near-net-shape forging apparatus for metal powder additive manufacturing according to claim 1, characterized in that: One of the first blocks (41) is provided with a third block (61), the third block (61) having an inclined portion (611) that cooperates with the trigger (62). The inclined portion (611) is inclined along the path of the upper mold (2) close to the lower mold (1) so as to convert the movement of the trigger (62) into the movement of the first block (41) away from the first cavity (31).

8. The near-net-shape forging apparatus for metal powder additive manufacturing according to claim 7, characterized in that: The third block (61) also has a retaining part (612) connected to the inclined part (611), the retaining part (612) extending along the path of the upper mold (2) toward or away from the lower mold (1), and when the trigger (62) cooperates with the retaining part (612), the two first blocks (41) are held away from the first cavity (31).

9. The near-net-shape forging apparatus for metal powder additive manufacturing according to claim 1, characterized in that: The upper mold (2) has a second groove (71) surrounding the forging part (33). The ring (72) is slidably disposed in the second groove (71). A third elastic element (73) is provided between the ring (72) and the bottom of the second groove (71). The ring (72) has a limiting part (721) that cooperates with the bottom of the second groove (71). The limiting part (721) is used to limit the distance of the ring (72) entering the second groove (71).

10. A near-net-shape forging process for metal powder additive manufacturing, employing the near-net-shape forging apparatus for metal powder additive manufacturing as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Establish an additive blank model based on the shape of the target part, and set a material compensation part in the additive blank model corresponding to the corner, thin wall or cross-sectional change of the target part. S2. Using metal powder, the additive blank is formed layer by layer according to the additive blank model to obtain an additive blank with the material compensation part. The additive blank is then subjected to powder removal, support removal and stress relief treatment. S3. The additive blank is heated and the heated additive blank is loaded into the first cavity (31) of the lower mold (1), and the additive blank is clamped by the plates (42) located on both sides of the first cavity (31). S4. Drive the upper die (2) closer to the lower die (1) so that the ring (72) arranged around the forging part (33) presses against the additive blank before the forging part (33); S5. After the ring (72) presses against the additive blank and reaches the preset pre-press state, the trigger (62) that moves with the upper mold (2) drives the two first blocks (41) to move away from each other, so that the two plates (42) are separated from the additive blank and exit the movement range of the forging part (33). S6. Continue to drive the upper die (2) closer to the lower die (1), so that the forging part (33) and the first cavity (31) jointly extrude the additive blank, and the metal material of the material compensation part flows to the corresponding forming part to obtain a near-net-shape forging; S7. After the forging part (33) is withdrawn, the ring body (72) separates the near-net-shape forging from the forging part (33), the upper die (2) continues to move away from the lower die (1), and the trigger (62) releases the restriction on the third block (61). The second elastic element (54) drives the two first blocks (41) to reset through the third meshing element (53). S8. Remove the near-net-shape forging and perform cooling, surface cleaning, machining and heat treatment on the near-net-shape forging.

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