NdFeB production raw material blank powder profiling jig

Abstract

The invention relates to the technical field of blank powder profiling jigs, in particular to a neodymium iron boron production raw material blank powder profiling jig which comprises a wrapping frame, an avoiding groove is formed in the bottom of the wrapping frame, a limiting piece formed by modular splicing is placed in the wrapping frame, a mold piece is placed in the limiting piece, and the mold piece is connected with the wrapping frame. The front side, the rear side, the left side and the right side of the mold part are each provided with at least one containing groove, and a rolling type calibration part used for centrally calibrating the mold part and reducing abrasion between the limiting part and the mold part at the same time is detachably installed in each containing groove. Sliding friction is converted into rolling friction through the modularized rolling type calibration piece, friction resistance is greatly reduced, the service life of the profiling jig is effectively prolonged, metal scraps are reduced, and magnetic powder pollution is avoided.

Description

Technical Field

[0001] This invention relates to a blank powder pressing fixture, and more particularly to a blank powder pressing fixture for neodymium iron boron production. Background Technology

[0002] In the fabrication process of sintered NdFeB permanent magnets, powder pressing is a crucial step that determines the final performance and dimensional accuracy of the magnet. This process requires filling a mold cavity with micron-sized anisotropic magnetic powder under a strong orientation magnetic field (typically ≥2T), and applying pressure to initially densify it, forming a "green blank" with a certain strength. Subsequently, the green blank needs to be removed from the mold and proceed to the subsequent sintering process.

[0003] However, under high-frequency, continuous production conditions, the repeated pushing and pushing of the mold parts into and out of the forming fixture causes continuous sliding friction between them and the fixture's limiting structure. This friction not only accelerates the mechanical wear of the mold sidewalls and the fixture's inner cavity, resulting in increased clearance and decreased positioning accuracy, but also contaminates the high-purity NdFeB magnetic powder due to the shedding of metal shavings, thereby affecting the coercivity, remanence, and insulation properties of the sintered magnet.

[0004] Existing molding fixtures mostly employ rigid surface contact limiting methods. While simple in structure, they cannot avoid the aforementioned friction problems. Some solutions attempt to alleviate wear through surface hardening treatments or lubricating coatings, but these cannot fundamentally eliminate the sliding friction mechanism. Furthermore, in the extremely clean magnetic material production environment, lubricants may introduce impurities. In addition, once critical components of traditional fixtures wear out, the entire fixture usually needs to be replaced, resulting in high maintenance costs and making it difficult to meet the demands of modern production processes that require diverse products, small batches, and high efficiency.

[0005] Therefore, there is an urgent need for a molding fixture for NdFeB raw material powder that can significantly reduce friction and wear without sacrificing positioning accuracy, and support rapid local maintenance, effectively solving problems such as severe fixture wear, inaccurate positioning, and high maintenance costs. Summary of the Invention

[0006] To overcome the drawbacks of severe jig wear, inaccurate positioning, and high maintenance costs, this invention provides a jig for pressing neodymium iron boron raw material powder.

[0007] A molding fixture for NdFeB raw material powder includes a covering frame with a clearance groove at the bottom. A modularly assembled limiting component is placed inside the covering frame, and a mold component is placed inside the limiting component. At least one placement groove is opened on each of the four sides of the mold component. A rolling calibration component for centering and calibrating the mold component and reducing wear between the limiting component and the mold component can be detachably installed in each placement groove.

[0008] In a preferred embodiment of the present invention, the covering frame is formed by splicing two halves of a panel.

[0009] In a preferred embodiment of the present invention, the limiting member includes a first limiting plate arranged symmetrically front to back and a second limiting plate arranged symmetrically left to right. The inner side of the first limiting plate has a limiting groove symmetrically distributed along the first limiting plate, and the second limiting plate is inserted into the limiting groove on the same side.

[0010] In a preferred embodiment of the present invention, the mold component includes an upper mold and a lower mold, the upper mold is placed on the lower mold, and the end faces of the upper mold and the lower mold that are close to each other are provided with continuously distributed semi-circular forming grooves, and the forming grooves on the upper and lower sides correspond to each other.

[0011] In a preferred embodiment of the present invention, the rolling calibration component includes a mounting plate, which is fixedly connected to each of the placement slots. The mounting plate is provided with a plurality of partitions symmetrically distributed along the top and bottom of the mounting plate. A slot is formed between adjacent partitions. An elastic card is engaged between any two corresponding slots. A roller is rotatably connected to the middle of the elastic card.

[0012] In a preferred embodiment of the present invention, the elastic card has mounting cavities symmetrically distributed along the axis roller for the thumb to press and deform the elastic card.

[0013] In a preferred embodiment of the present invention, each half of the enclosure of the covering frame has a clamping opening.

[0014] In a preferred embodiment of the present invention, the bottom of the upper mold is provided with a first bearing plane symmetrically distributed along the upper mold, and a first inclined surface is provided on the side of the upper mold close to each of the first bearing planes. The top of the lower mold is provided with a second bearing plane symmetrically distributed along the lower mold, and the top of the lower mold is provided with a third inclined surface symmetrically distributed along the second bearing plane. When the first bearing plane is aligned downward and contacts the second bearing plane on the same side, the third inclined surface is pressed and engaged with the first inclined surface on the same side.

[0015] In a preferred embodiment of the present invention, the bottom of the upper mold is provided with a second inclined surface symmetrically distributed along the first bearing plane, and the top of the lower mold is provided with a fourth inclined surface symmetrically distributed along the second bearing plane. When the first bearing plane is aligned downward and contacts the second bearing plane on the same side, the second inclined surface and the fourth inclined surface on the same side are pressed together.

[0016] In a preferred embodiment of the present invention, each half of the enclosure of the covering frame is fixedly connected to a fixing plate that is symmetrically distributed thereal, and each fixing plate has a through hole. Beneficial effects

[0017] 1. This invention transforms large-area, high-resistance sliding friction into small-area, low-resistance rolling friction through modular rolling calibration components, thereby reducing wear between mold parts and limiting parts, effectively extending the life of the forming fixture, reducing metal debris generation, and avoiding magnetic powder contamination.

[0018] 2. This invention uses the elastic force of the elastic card to keep the roller always in contact with the limiting surface. Even if there is wear, it can automatically and dynamically adjust its position to ensure that the mold part automatically maintains centering stability and dynamic compensation during the pressing and demolding process, preventing shaking and deviation, thereby avoiding product molding failure.

[0019] 3. The limiting plate and rolling calibration component of the present invention can be disassembled and replaced independently, and the position of the roller shaft can be flexibly adjusted through multi-level slots to achieve "partial repair and overall reuse", avoiding the scrapping of the entire fixture. Thus, the large number of modular designs can significantly reduce maintenance and replacement costs.

[0020] 4. This invention uses a vertical demolding path combined with an avoidance groove design to avoid lateral scraping, reduce the risk of green body chipping and powder shedding, and ensure the integrity and cleanliness of the green body during demolding.

[0021] 5. This invention utilizes a multi-level inclined surface structure to guide the upper mold to automatically complete front-back and left-right calibration during the falling process, ensuring precise alignment of the corresponding forming grooves and improving the consistency of green blank size and uniformity of magnetic properties. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural schematic diagram from the first perspective of the present invention.

[0023] Figure 2 This is a bottom view of the three-dimensional structure from the second perspective of the present invention.

[0024] Figure 3 This is a three-dimensional structural diagram of the second limiting plate and the upper mold of the present invention.

[0025] Figure 4 This is a three-dimensional structural diagram of the first limiting plate and the lower mold of the present invention.

[0026] Figure 5 This is a three-dimensional structural diagram of the upper mold, lower mold, and rolling calibration component of the present invention.

[0027] Figure 6 This is a three-dimensional structural diagram of the rolling calibration component of the present invention.

[0028] Figure 7 This is a three-dimensional structural diagram of the elastic card and roller of the present invention.

[0029] Figure 8 This is a three-dimensional structural diagram of the first and second inclined surfaces of the present invention.

[0030] Figure 9 This is a partial three-dimensional structural diagram of the first and second inclined surfaces of the present invention.

[0031] Figure 10 This is a three-dimensional structural diagram of the third inclined surface and the fourth inclined plane of the present invention.

[0032] Figure 11 This is a three-dimensional structural diagram of the components such as the covering frame and fixing plate of the present invention.

[0033] The above-mentioned figures include the following reference numerals: 101, covering frame; 102, clearance groove; 103, first limiting plate; 104, limiting groove; 105, second limiting plate; 106, upper mold; 107, lower mold; 108, forming groove; 109, placement groove; 110, rolling calibration component; 1101, mounting plate; 1102, partition; 1103, card slot; 1104, elastic card; 1105, mounting cavity; 1106, roller; 111, clamping opening; 201, first bearing plane; 202, first inclined plane; 203, second inclined plane; 204, third inclined plane; 205, second bearing plane; 206, fourth inclined plane; 301, fixing plate; 302, through hole. Detailed Implementation

[0034] First, it should be noted that in different described embodiments, the same components are given the same reference numerals or the same component names. The disclosure contained throughout this specification can be applied semantically to the same components having the same reference numerals or the same component names. The location descriptions selected in the specification, such as upper, lower, and lateral, also refer to the directly described and illustrated figures and are semantically applied to the new location when the location changes.

[0035] Example 1: This invention proposes a molding fixture for NdFeB raw material powder. Its core objective is to balance the three key requirements of high-precision molding, low-wear operation and convenient maintenance in a high-frequency and continuous production rhythm.

[0036] In traditional molding fixtures, the mold and the limiting frame are in a state of large-area sliding friction for a long time during repeated mold loading and unmolding. This not only leads to rapid wear of the mold sidewalls and widening of the mating clearance, causing positioning misalignment and clamping failure, but also causes metal debris to detach and contaminate the high-purity magnetic powder, directly affecting the coercivity, remanence consistency, and insulation performance of the final magnet. Existing improvement solutions mostly focus on surface hardening or lubrication treatment, which cannot fundamentally eliminate the sliding friction mechanism and lacks the ability to flexibly respond to localized wear.

[0037] To address the aforementioned pain points, this fixture adopts an integrated yet highly modular architecture, consisting of four parts working together: the covering frame 101, the limiting component, the mold component, and the rolling calibration component 110. This forms a closed-loop system that comprehensively covers the entire lifecycle operation requirements from mold assembly, pressing, demolding to maintenance.

[0038] See attached document Figure 1 and attached Figure 2 The covering frame 101, serving as the overall supporting shell, is composed of two halves of a panel, facilitating disassembly and replacement of internal components. This modular design significantly improves on-site maintenance efficiency—when an internal component is damaged, the entire machine can be opened for inspection without disassembling the machine or damaging the external fixing structure; simply loosening the connecting bolts is sufficient. The bottom of the covering frame 101 features a clearance groove 102, which allows the entire mold part to be vertically pushed upwards from below via a push rod or cylinder after molding, achieving a demolding path without lateral scraping and effectively preventing edge chipping, powdering, or micro-cracks in the green blank due to friction. The upper center of the two halves of the covering frame 101 on both the front and rear sides has a clamping opening 111, ideally designed to match the standard clamping end of an industrial robotic gripper, facilitating rapid gripping, handling, and precise positioning in automated production lines.

[0039] See attached document Figure 3 The covering frame 101 houses a limiting component, which employs a modular splicing structure, including a first limiting plate 103 symmetrically arranged front to back and a second limiting plate 105 symmetrically arranged left to right. The inner side of the first limiting plate 103 has symmetrically distributed limiting grooves 104. The two ends of the second limiting plate 105 respectively engage with the corresponding limiting grooves 104, forming a stable "well"-shaped limiting frame. This structure not only ensures that the mold parts can only slide vertically, preventing them from wobbling back and forth or left and right during high-pressure pressing or high-speed demolding, but also allows for independent replacement of each first limiting plate 103 and second limiting plate 105—when one side wears down due to long-term use, the entire fixture does not need to be scrapped; only the damaged plate needs to be replaced to restore the original fit accuracy, significantly reducing maintenance costs. The first limiting plate 103 and the second limiting plate 105 are preferably made of high-strength tool steel or surface-nitrided alloy structural steel, possessing both high hardness and good fatigue resistance, suitable for thousands of cycles of use.

[0040] See attached document Figure 4The limiting component houses a mold component, which consists of an upper mold 106 and a lower mold 107. The lower mold 107 is placed inside the limiting component, and its top end face has continuously distributed semi-circular forming grooves 108. The upper mold 106 is stacked on top of the lower mold 107, and its bottom surface also has corresponding semi-circular forming grooves 108. After the upper and lower molds 107 are closed, the two sets of semi-circular grooves together form a complete cylindrical cavity for accommodating micron-sized NdFeB anisotropic magnetic powder obtained by hydrogen crushing and air jet milling. Under the action of a strong orientation magnetic field (typically ≥2T), the magnetic powder particles are arranged in an orderly manner along the direction of the magnetic field. Then, uniaxial pressure (typically 100–300MPa) is applied for pressing and forming multiple independent cylindrical blanks. The mold material is usually non-magnetic stainless steel (such as SUS304) or hard alloy to avoid interfering with the orientation magnetic field and to have good wear resistance and demolding performance.

[0041] See attached document Figure 4 In mass production, the mold parts need to be repeatedly pushed into the limiting parts for pressing and then pushed out from the bottom clearance groove 102 to remove the blank. If this reciprocating motion adopts the traditional surface contact method, it will cause severe sliding friction between the mold parts and the first limiting plate 103 and the second limiting plate 105, accelerating wear and introducing metal debris contamination. To address this, the present invention provides two symmetrical placement grooves 109 on the front and rear sides of both the upper mold 106 and the lower mold 107, with one placement groove 109 on each side. Each placement groove 109 can be detachably installed with a rolling calibration component 110.

[0042] See attached document Figure 5 To be continued Figure 8 The rolling calibration component 110 consists of a mounting plate 1101, separators 1102, elastic clips 1104, and a roller 1106. The mounting plate 1101 is securely fixed to the placement groove 109 by screws or welding. Its surface has multiple separators 1102 symmetrically distributed vertically, with adjacent separators 1102 forming a slot 1103. The elastic clips 1104 are U-shaped, V-shaped, or C-shaped, stamped from highly elastic stainless steel, and their ends can be inserted into any set of corresponding slots 1103. A high-hardness, high-gloss roller 1106 is rotatably connected to the center of the clip via a pin or bearing. The surface of the roller 1106 is mirror-polished or coated with a diamond-like coating, resulting in a low coefficient of friction, far superior to ordinary metal sliding pairs. The elastic card 1104 is also provided with mounting cavities 1105 that are symmetrically distributed along the roller shaft 1106. The operator can use his thumb and forefinger to pinch the mounting cavity 1105 to deform the two ends of the elastic card 1104 inward, and easily insert or remove it into the slot 1103. After being released, the elastic card 1104 automatically resets and locks itself by its own rebound force, so as to achieve quick installation and removal.

[0043] After the mold part is placed into the limiting member, the rollers 1106 on its four sides form a rolling pair with the inner surfaces of the first limiting plate 103 and the second limiting plate 105 in point / line contact. During the pushing or pushing process, the original large-area, high-resistance sliding friction is transformed into small-area, low-resistance rolling friction, significantly reducing friction and effectively protecting the surface of the mold part from scratches. At the same time, the elasticity of the elastic card 1104 keeps the rollers 1106 in close contact with the inner wall of the first limiting plate 103 or the second limiting plate 105. Even if wear gaps occur due to long-term use, they can be dynamically compensated to ensure that the mold part remains centered and stable without shaking, thereby ensuring the repeatability of positioning accuracy for each pressing and improving the success rate of product molding.

[0044] Furthermore, this structure boasts high maintainability: if only the roller 1106 is worn, the corresponding elastic card 1104 can be replaced individually without replacing the entire mold component; if only the first limiting plate 103 or the second limiting plate 105 shows minor wear on its contact surface, the elastic card 1104 can be moved to the spare card slot 1103 on the same side, allowing the roller 1106 to contact the unworn area, extending its overall service life; if only the first limiting plate 103 or the second limiting plate 105 shows extensive wear on its contact surface, only the severely worn first limiting plate 103 or second limiting plate 105 needs to be replaced, while the remaining components continue to be used. This "replace as needed, repair locally" design concept completely changes the high-cost "one-piece damage, all-out failure" model of traditional jigs, significantly reducing the replacement and maintenance costs of molding jigs, and is especially suitable for scenarios with frequent changes, such as R&D trials, multi-product switching, or teaching experiments.

[0045] Example 3: Based on Example 2, refer to Appendix Figure 8 To be continued Figure 10 To ensure precise alignment of the upper and lower molds 107 during mold closing and to avoid misalignment leading to deviations in green blank dimensions, disordered magnetic field orientation, or even pressing failure, this invention innovatively designs a multi-level self-aligning inclined surface structure on the mold contact surface: the bottom of the upper mold 106 is provided with a first bearing plane 201 symmetrically distributed along its left and right sides, and a first inclined surface 202 is provided on the side of the upper mold 106 near each first bearing plane 201. The bottom of the upper mold 106 is provided with a second inclined surface 203 symmetrically distributed along the front and back of the first bearing plane 201; the top of the lower mold 107 is provided with a second bearing plane 205 symmetrically distributed along its left and right sides, and the top of the lower mold 107 is provided with a third inclined surface 204 and a fourth inclined surface 206 symmetrically distributed along the front and back of the second bearing plane 205. When the first bearing plane 201 is aligned downwards and contacts the second bearing plane 205 on the same side, the third inclined surface 204 is pressed and engaged with the first inclined surface 202 on the same side, and the second inclined surface 203 is pressed and engaged with the corresponding fourth inclined surface 206 on the same side.

[0046] When the upper mold 106 falls close to the lower mold 107 under the influence of gravity or slight downward pressure, the first inclined surface 202 and the third inclined surface 204 first contact and press against each other, using the inclined surface guiding effect to guide the upper mold 106 to automatically complete the left-right correction. At the same time, the second inclined surface 203 at both ends contact and press against the fourth inclined surface 206, achieving automatic front-back alignment. Finally, the first bearing surface 201 of the upper mold 106 smoothly lands on the second bearing surface 205 of the lower mold 107, completing high-precision mold closing and ensuring that all forming grooves 108 are strictly aligned. This self-alignment mechanism requires no additional sensors or servo mechanisms, relying entirely on geometric constraints to achieve high-precision repeatable positioning.

[0047] Example 3: Based on Example 2, and further, refer to the appendix. Figure 11 Each half of the enclosure panel is fixedly attached to its outer side with symmetrically distributed fixing plates 301. The fixing plates 301 have through holes 302. By passing bolts through the two through holes 302 on the same side and engaging locking nuts, the two halves of the enclosure panel can be securely connected. More importantly, by adjusting the tightness of the nuts, the clamping force of the covering frame 101 on the internal limiting components can be controlled—moderately tightening during the pressing stage to enhance rigidity, and moderately loosening during demolding or mold replacement to reduce resistance, achieving a dynamic adaptation that combines rigidity and flexibility.

[0048] In summary, this invention, through its four innovative mechanisms of "modular positioning, rolling calibration, self-aligning mold closing, and adjustable covering locking," fundamentally solves the wear and contamination problems caused by high-frequency demolding while ensuring high-precision forming of NdFeB green blanks. It is not only suitable for mass production of cylindrical magnets, but can also be adapted to block, arc-shaped, or other irregularly shaped cross-section products by changing the mold components, demonstrating excellent versatility and expansion potential.

[0049] Although this disclosure has been described with respect to only a limited number of embodiments, those skilled in the art who benefit from this disclosure will understand that various other embodiments can be devised without departing from the scope of the invention. Therefore, the scope of the invention should be limited only by the appended claims.

Claims

1. A molding jig for NdFeB raw material powder, characterized in that it includes: There is a cover frame (101), and the bottom of the cover frame (101) has a clearance groove (102). A limiting component made of modular splicing is placed inside the cover frame (101). A mold component is placed inside the limiting component. At least one placement groove (109) is opened on the front, back, left and right sides of the mold component. A rolling calibration component (110) for centering and calibrating the mold component and reducing wear between the limiting component and the mold component can be detachably installed in each placement groove (109).

2. A pressing fixture for NdFeB production raw material powder according to claim 1, characterized in that, The covering frame (101) is composed of two halves of a panel spliced ​​together.

3. A pressing fixture for NdFeB production raw material powder according to claim 2, characterized in that, The limiting component includes a first limiting plate (103) arranged symmetrically in front and behind and a second limiting plate (105) arranged symmetrically in the left and right. The inner side of the first limiting plate (103) has a limiting groove (104) symmetrically distributed along the first limiting plate (103), and the second limiting plate (105) is inserted into the limiting groove on the same side.

4. A pressing fixture for NdFeB production raw material powder according to claim 3, characterized in that, The mold component includes an upper mold (106) and a lower mold (107). The upper mold (106) is placed on the lower mold (107). The upper mold (106) and the lower mold (107) have continuously distributed semi-circular forming grooves (108) on their adjacent end faces. The forming grooves (108) on the upper and lower sides correspond to each other.

5. A pressing fixture for NdFeB production raw material powder according to claim 4, characterized in that, The rolling calibration component (110) includes a mounting plate (1101), which is fixedly connected to each of the placement slots (109). The mounting plate (1101) is provided with a plurality of partitions (1102) symmetrically distributed vertically along the mounting plate (1101). A slot (1103) is formed between adjacent partitions (1102). An elastic card (1104) is engaged between any vertically corresponding slot (1103). A roller (1106) is rotatably connected to the middle of the elastic card (1104).

6. A pressing fixture for NdFeB production raw material powder according to claim 5, characterized in that, The elastic card (1104) has mounting cavities (1105) symmetrically distributed along the shaft roller, which are used for the thumb to press and deform the elastic card (1104).

7. A pressing fixture for NdFeB production raw material powder according to claim 6, characterized in that, Each half of the enclosure of the covering frame (101) has a clamping opening (111).

8. A pressing fixture for NdFeB production raw material powder according to claim 7, characterized in that, The bottom of the upper mold (106) is provided with a first bearing plane (201) symmetrically distributed along the upper mold (106). The upper mold (106) is provided with a first inclined surface (202) on the side close to each of the first bearing planes (201). The top of the lower mold (107) is provided with a second bearing plane (205) symmetrically distributed along the lower mold (107). The top of the lower mold (107) is provided with a third inclined surface (204) symmetrically distributed along the second bearing plane (205). When the first bearing plane (201) is aligned downward and contacts the second bearing plane (205) on the same side, the third inclined surface (204) and the first inclined surface (202) on the same side are pressed together.

9. A pressing fixture for NdFeB production raw material powder according to claim 8, characterized in that, The bottom of the upper mold (106) is provided with a second inclined surface (203) symmetrically distributed along the first bearing plane (201), and the top of the lower mold (107) is provided with a fourth inclined surface (206) symmetrically distributed along the second bearing plane (205). When the first bearing plane (201) is aligned downward and contacts the second bearing plane (205) on the same side, the second inclined surface (203) and the fourth inclined surface (206) on the same side are pressed together.

10. A pressing fixture for NdFeB production raw material powder according to claim 9, characterized in that, Each half of the enclosure of the covering frame (101) is fixed with a fixing plate (301) that is symmetrically distributed thereon, and each fixing plate (301) has a through hole (302).

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