Demolding mechanism and preparation method of nearly-formed tile-shaped magnetic steel

Abstract

The invention provides a demolding mechanism for nearly-formed tile-shaped magnetic steel and a preparation method of the demolding mechanism, and belongs to the technical field of permanent magnet preparation. The demolding mechanism comprises a base, a load bearing plate, a powder filling device and a punch; wherein the base is provided with a bottom plate and a top plate which are oppositely arranged; the load bearing plate, the powder filling device and the punch are sequentially stacked between the bottom plate and the top plate in a relatively movable manner; and when the punch, the load bearing plate and the powder filling device generate relative displacement, the tile-shaped magnetic steel forming body which is nearly formed is demolded from the load bearing plate. Through relative displacement of the punch, the load bearing plate and the powder filling device, the formed body is directly demolded from the load bearing plate, grabbing is not needed, the load bearing plate is directly transferred, the problem that a magnet cannot be grabbed and transferred is solved, the uniform small tile-shaped magnetic steel formed body can be obtained, and batch production is achieved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of permanent magnet preparation, and particularly to a demolding mechanism and a preparation method for near-shaped tile-shaped magnetic steels. Background Art

[0002] With the increasing pursuit of energy conservation and emission reduction goals globally, permanent magnet motors will be more widely used in industrial production, transportation, household appliances and other fields due to their high efficiency and low energy consumption characteristics. Especially in industrial motor systems, replacing traditional motors with permanent magnet motors can significantly improve the overall efficiency of the system, reduce energy consumption and carbon emissions. The trend of lightweight and miniaturization also brings new development opportunities to the permanent magnet motor magnetic steel industry. With the increasing requirements for motor lightweight and miniaturization in industries such as aerospace, medical devices, and portable electronic devices, the design of permanent magnet motors will pay more attention to integration and modularization, and use advanced manufacturing processes and materials to develop higher-performance and more compact products to meet specific application requirements.

[0003] High magnetic energy product, lightweight, and small volume have become the mainstream of the industry's magnetic steel development. Currently, the thickness of product specifications is mostly 1 - 10 mm. The mainstream method in the industry is to mold large blanks, process them into small squares, diffuse them, and finally finish them into tile-shaped products, but the processing procedures of the magnets are numerous and the utilization rate is low. Currently, there are also near-shaped methods to develop tile-shaped magnetic steels, but the green strength of near-shaped tile-shaped magnetic steels is low, the thickness direction is thin, and it is difficult to stably feed the magnets into the sintering furnace before sintering, and mass production cannot be achieved. Summary of the Invention

[0004] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a demolding mechanism and a preparation method for near-shaped tile-shaped magnetic steels.

[0005] On one hand of the present disclosure, a demolding mechanism for near-shaped tile-shaped magnetic steels is provided. The demolding mechanism includes: a base, a sintering plate, a powder filling device, and a punch; wherein,

[0006] The base has a bottom plate and a top plate arranged oppositely; the sintering plate, the powder filling device, and the punch are sequentially stacked between the bottom plate and the top plate in a relatively movable manner;

[0007] When relative displacements occur among the punch, the sintering plate, and the powder filling device, a near-shaped tile-shaped magnetic steel formed body is demolded from the sintering plate.

[0008] Optionally, when it is necessary to demold the tile-shaped magnetic steel formed body, the punch and the sintering plate move downward synchronously, and the powder filling device remains stationary.

[0009] Optionally, when demolding the tile-shaped magnet compact, the punch moves downward to the position of the powder filling device, the punch and the sintering plate remain stationary, and the powder filling device moves upward.

[0010] Optionally, the powder filling device has a plurality of cavities penetrating through its thickness, and partitions are arranged between the cavities. The partitions are demolded from the sintering plate synchronously with the tile-shaped magnet compact.

[0011] Optionally, the thickness of the partition is 0.1 - 2 mm.

[0012] Optionally, the demolding mechanism further includes a control module for fitting the tile-shaped magnet compact after demolding.

[0013] Optionally, the rate at which the control module controls the fitting of the tile-shaped magnet compact is 0.01 - 10 mm / s.

[0014] On the other hand, the present disclosure proposes a method for preparing a tile-shaped magnet, and the preparation method includes the following steps:

[0015] Melting Nd, Fe, and B powders to form a thin-film alloy, and obtaining magnetic powder through hydrogenation, dehydrogenation, and jet milling treatments;

[0016] Near-shaping and orienting the magnetic powder, demolding the compact using the demolding mechanism described above, and obtaining a tile-shaped magnet compact on the sintering plate;

[0017] Placing the sintering plate with the tile-shaped magnet compact on a sintering platform, and obtaining a magnet through heating, heat preservation, and cooling treatments;

[0018] Removing the oxide layer on the surface of the magnet;

[0019] Performing coating treatment and diffusion treatment on the magnet;

[0020] Performing grinding on the surface of the magnet;

[0021] Performing surface plating on the magnet to obtain a tile-shaped magnet.

[0022] Optionally, the mass of the tile-shaped magnet compact is 1 - 100 g, the thickness is 1 - 10 mm, the density is 3.4 g / cm 3 - 4.0 g / cm 3 , and the number of compacts per mold is 1 - 100 pcs.

[0023] Optionally, before placing the sintering plate with the tile-shaped magnet compact on the sintering platform, it further includes:

[0024] Setting partitions between the tile-shaped magnet compacts; or,

[0025] Bond the shaped tile magnet body.

[0026] The present disclosure provides a demolding mechanism for a near-shaped tile magnet and a preparation method therefor. The demolding mechanism includes: a base, a sintering plate, a powder filling device, and a punch. Among them, the base has a bottom plate and a top plate arranged opposite to each other; the sintering plate, the powder filling device, and the punch are sequentially stacked between the bottom plate and the top plate in a relatively movable manner; when relative displacement occurs among the punch, the sintering plate, and the powder filling device, the near-shaped tile magnet formed body is demolded from the sintering plate. By causing relative displacement among the punch, the sintering plate, and the powder filling device, the present disclosure enables the formed body to be directly demolded from the sintering plate without grasping, and only the sintering plate needs to be directly transferred, solving the problem that the magnet cannot be grasped and transferred, and enabling a uniform small tile magnet formed body to be obtained, realizing batch production. Description of the Drawings

[0027] Figure 1 is a schematic structural diagram of the demolding mechanism according to a specific embodiment of the present disclosure;

[0028] Figure 2 is a schematic structural diagram of the demolding mechanism according to a specific embodiment of the present disclosure;

[0029] Figure 3 is a sectional view of the demolding mechanism according to a specific embodiment of the present disclosure;

[0030] Figure 4 is a sectional view of the demolding mechanism according to a specific embodiment of the present disclosure;

[0031] Figure 5 For the present disclosure Figure 4 is a partial enlarged view of part A in;

[0032] Figure 6 is a top view of the tile magnet formed body according to a specific embodiment of the present disclosure;

[0033] Figure 7 is a top view of the tile magnet formed body according to a specific embodiment of the present disclosure;

[0034] Figure 8 is a flowchart of the method for preparing a tile magnet according to a specific embodiment of the present disclosure. Specific Embodiments

[0035] To enable those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be further described in detail below with reference to the drawings and specific embodiments. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0036] AsFigure 1 and Figure 2 As shown in Figure 2 , on one hand of the present disclosure, a demolding mechanism 100 for a near-shaped tile-shaped magnet is proposed, including: a base 110, a firing plate 120, a powder filling device 130, and a punch 140; wherein, the base 110 has a bottom plate 111 and a top plate 112 arranged oppositely; the firing plate 120, the powder filling device 130, and the punch 140 are sequentially stacked between the bottom plate 111 and the top plate 112 in a relatively movable manner. In this way, when relative displacements occur among the punch 140, the firing plate 120, and the powder filling device 130, the near-shaped tile-shaped magnet formed body 150 is demolded from the firing plate 120.

[0037] It should be understood that for the near-shaped small tile-shaped magnet, the density of its formed body is relatively low, lower than that of the formed body by the traditional die pressing method, and the thickness is relatively thin, which makes it inconvenient to grasp the tile-shaped magnet formed body. In view of this, in this embodiment, by enabling relative displacements among the punch, the firing plate, and the powder filling device, the tile-shaped magnet formed body is directly demolded from the firing plate, and the firing plate on which the tile-shaped magnet is placed is directly used for sintering, without the process of grasping the formed body, solving the problem that the small tile-shaped magnet cannot be grasped and transferred, and realizing batch production.

[0038] It should be noted that the connection manner between the bottom plate and the top plate in this embodiment is not specifically limited. For example, as Figure 1 and Figure 2 shown, support columns 113 are respectively arranged at both ends of the bottom plate 111 and the top plate 112 for connecting the bottom plate 111 and the top plate 112, and the top plate 112 can move up and down along the support columns 113.

[0039] Furthermore, it should be noted that the connection manner among the punch, the powder filling device, and the firing plate in this embodiment is not specifically limited either, as long as relative displacements among the powder filling device, the punch, and the firing plate can be realized. For example, as Figures 1 to 3 shown, a plurality of first connectors 160 are passed through the firing plate 120, the powder filling device 130, and the punch 140, and the powder filling device 130 can move up and down along the first connectors 160 to realize relative displacements among the powder filling device, the punch, and the firing plate.

[0040] Of course, it should be understood that the number of the first connectors in this embodiment is not specifically limited. One first connector can be respectively arranged at both ends of the firing plate, the punch, and the powder filling device, or two first connectors can be respectively arranged at both ends of the firing plate, the punch, and the powder filling device, etc.

[0041] It should also be understood that when the tile-shaped magnet formed body is demolded from the firing plate, the firing plate should be located on the bottom plate of the base, facilitating its transfer to the sintering platform, as Figure 3As shown, in some preferred embodiments, in order to fix the firing plate 120, a plurality of fixing members 170 are provided on the bottom plate 111. The plurality of fixing members 170 surround the peripheral side of the firing plate 120, play a positioning role when the firing plate 120 moves downward, and can also clamp and fix the firing plate 120 on the bottom plate 111.

[0042] It should be noted that the structure and position of the fixing member are not specifically limited in this embodiment. As long as the firing plate can be limited, for example, other structures such as protrusions can be used. The protruding fixing members can be arranged on both sides of the firing plate along its length direction, or on both sides along its width direction, or can be arranged in both its length direction and width direction.

[0043] Of course, in addition, the punch should also be connected to the top plate. As Figures 1 to 4 shown, a plurality of second connecting members 180 are provided through between the top plate 112 and the punch 140. And after the shaped body 150 of the tile-shaped magnet is demolded, the end of the second connecting member 180 is clamped in the powder filling device 130, which indicates that the demolding of the shaped body 150 of the tile-shaped magnet is completed.

[0044] In some preferred embodiments, as Figure 4 and Figure 5 shown, a clamping groove 131 is provided on the side of the powder filling device 130 facing the punch 140. A clamping protrusion 181 is provided at the end of the second connecting member 180. The clamping protrusion 181 is clamped in the clamping groove 131 to play a limiting role.

[0045] As a further preferred solution, as Figure 4 and Figure 5 shown, the cross-sectional dimension of the clamping protrusion 181 is smaller than the cross-sectional dimension of the second connecting member 180. That is to say, the size of the clamping protrusion provided at the end of the second connecting member is smaller than the other connecting areas of the second connecting member, ensuring that the clamping protrusion is clamped in the clamping groove.

[0046] It should also be understood that the punch includes a punch top plate and a plurality of punching heads. The punch top plate is connected to the top plate of the base. The plurality of punching heads are evenly distributed on the side of the punch top plate facing the powder filling device. At the same time, the powder filling device has a cavity penetrating through its thickness, and the shape and size of the cavity match the punching heads.

[0047] Based on the above structure, the demolding method of this embodiment includes a downward pressing type and an upward lifting type. Among them, as Figures 1 to 7As shown in the figure, when using the downward pressing demoulding method, accurate positioning can be achieved while ensuring that the formed body of the tile-shaped magnet does not shake or decline. The punch 140 and the sintering plate 120 move downward synchronously, and the powder filling device 130 remains stationary. In this way, when the punch 140 presses downward, a relative displacement occurs between the punch 140 and the formed body of the tile-shaped magnet 150, and the formed body of the tile-shaped magnet 150 is directly demoulded from the sintering plate 120. After that, the sintering plate 120 with the formed body is transferred to the sintering platform for sintering treatment, the powder filling device 130 remains stationary, and the punch 140 is lifted and separated. In this way, the die cavities of the punch 140 and the powder filling device are separated, and the powder filling device 130 rotates back to the demoulding mechanism.

[0048] Furthermore, as Figures 1 to 7 shown in the figure, when using the upward lifting demoulding method, accurate positioning can be achieved while ensuring that the formed body does not shake or decline. The punch 140 moves downward to the position of the powder filling device 130, the punch 140 and the sintering plate 120 remain stationary, and the powder filling device 130 moves upward, causing a relative displacement between the punch 140 and the formed body of the tile-shaped magnet 150, and the formed body of the tile-shaped magnet 150 is directly demoulded from the sintering plate 120. After that, the sintering plate 120 with the formed body is transferred to the sintering platform for sintering treatment, the powder filling device 130 remains stationary, and the punch 140 is lifted and separated. In this way, the die cavities of the punch 140 and the powder filling device are separated, and the powder filling device 130 rotates back to the demoulding mechanism.

[0049] It should still be noted that since the thickness of the formed body of the small tile-shaped magnet is relatively thin, generally 1 - 10 mm, after demoulding, these small formed bodies of the tile-shaped magnet remain upright. When moving the graphite sintering plate, it is easy to cause the formed body to fall over, resulting in cracking of the blank. Therefore, in some preferred embodiments, as Figure 6 shown in the figure, a partition plate 190 is provided between each formed body of the tile-shaped magnet 150. The formed body of the tile-shaped magnet 150 and the formed body of the tile-shaped magnet 150 are separated by the partition plate 190, and the partition plate 190 is completely attached to the formed body of the tile-shaped magnet 150, effectively improving the strength and stability of the formed body.

[0050] It is not difficult to understand that the above partition plate can be synchronously removed from the formed body during demoulding. For example, the powder filling device has a plurality of die cavities penetrating its thickness, and an arc-shaped partition plate is provided between the die cavities, that is, the die cavities are divided by the partition plate, and the partition plate is used as a part of the die cavity composition to achieve powder filling and forming. During demoulding, the partition plate and the formed body are simultaneously demoulded onto the sintering plate, and the formed body remains in contact with the partition plate, avoiding the phenomenon of the formed body falling over during the transfer process.

[0051] It should be noted that the number of die cavities in this embodiment is not specifically limited. For example, 1 - 150 cavities can be preferably selected, and further 30 - 80 cavities can be preferably selected. Through multiple die cavities, multi-mode filling can be achieved, and thus multiple formed body samples can be formed in one mode.

[0052] As a further preferred solution, the thickness of the partition plate is 0.1-2 mm. For example, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, etc. can be preferably selected. Of course, the shape of the partition plate should match the shape of the tile-shaped magnet, and in addition, the material of the partition plate is not limited to SUS304, SUS306, SUS312, SUS316, and can also be a 0.1-2 mm thin plate such as a ceramic sheet that can withstand a high temperature of 1100 °C.

[0053] In some other preferred embodiments, the demolding mechanism further includes a control module for fitting the tile-shaped magnet formed body after demolding. The tile-shaped magnet formed body after fitting is as Figure 7 shown. That is to say, after the tile-shaped magnet formed body is demolded, the formed body remains upright without a partition plate, and there is a certain gap between the formed bodies. The formed bodies are slowly fitted by the automated control action of the control module, and then transferred for sintering, which can also avoid cracking and toppling of the formed body.

[0054] As a further preferred solution, the rate at which the control module controls the fitting of the tile-shaped magnet formed body is 0.01-10 mm / s. For example, 0.01 mm / s, 0.05 mm / s, 0.1 mm / s, 0.5 mm / s, 1 mm / s, 3 mm / s, 5 mm / s, 8 mm / s, 10 mm / s, etc. can be preferably selected.

[0055] As Figure 8 shown, on the other hand, the present disclosure proposes a preparation method S200 of a tile-shaped magnet, including the following steps S210 to S270:

[0056] S210: Melting Nd, Fe, and B powders to form a thin-film alloy, and obtaining magnetic powder through hydrogenation, dehydrogenation, and jet milling treatments.

[0057] Specifically, the raw material powders are proportioned, mixed, and melted to obtain a thin-film alloy. The thickness of the thin-film alloy is 1-4 μm, the columnar crystal size is 1.5-4 μm, the hydrogen absorption time is 1-4 h to ensure saturated hydrogen absorption, the dehydrogenation temperature is 500-650 °C, the time is 2-8 h, the particle size D50 of the jet-milled powder is 3-6 μm, and the added fine powder additive can preferably be zinc stearate or a short carbon chain organic reagent with a total amount of 0.005%-0.5%. A suitable additive and its content can improve the processing properties such as the fluidity and formability of the magnetic powder.

[0058] S220: Near-form orientation of the magnetic powder, demolding the formed body using the demolding mechanism described above, and obtaining a tile-shaped magnet formed body on the bearing plate.

[0059] Specifically, magnetic powder is filled into a preparation mold, a magnetic field is applied for orientation, and after orientation, the mold is demolded to directly obtain a tile-shaped magnet green body on a sintering plate. The entire process is carried out in a low-oxygen environment with an oxygen content of 100 ppm or less to reduce the influence of oxidation and improve the quality of the magnet. The mass of the green body is 1 - 1000 g, particularly preferably 1 - 100 g, the thickness is 1 - 10 mm, and the density is 3.4 g / cm 3 -4.0 g / cm 3 , and the number of green bodies per mold is 1 - 100 pcs.

[0060] It should be noted that the forming method of this embodiment is not limited to methods such as gas pressure, percussion vibration, and floating punch pressing.

[0061] S230: Place the sintering plate with the tile-shaped magnet green body on a sintering platform, and obtain the magnet through heating, heat preservation, and cooling treatments.

[0062] Specifically, the oxygen content in the furnace loading is less than 100 ppm, and the vacuum degree during the sintering process is less than 10 -1 Pa, which can effectively prevent the magnet green body from being oxidized during the sintering process, ensure the stability of the chemical composition of the magnet, and improve the quality of the magnet. Secondly, the sintering temperature is 1000 - 1100 °C, and the sintering duration is 4 - 15 h, providing a suitable thermal environment for the formation and optimization of the internal crystal structure of the magnet, helping to obtain ideal magnetic properties, and performing primary tempering at 850 - 950 °C for 2 - 6 h and secondary tempering at 450 - 550 °C for 2 - 6 h. By performing tempering treatment step by step, the internal stress generated during the sintering process can be eliminated, the organizational structure and mechanical properties of the magnet can be improved, and the stability and reliability of the magnet can be further enhanced.

[0063] S240: Remove the oxide layer on the surface of the magnet.

[0064] Specifically, pickling with dilute nitric acid is used. Dilute nitric acid pickling can effectively dissolve the oxide layer on the surface of the magnet, expose the clean magnet matrix, provide good surface conditions for subsequent processing, and after the surface of the magnet becomes shiny, it is washed clean with pure water to remove the oxide layer on the surface of the magnet, preventing the influence of surface oxidation or residual acid solution on the magnet performance and the effect of subsequent processing.

[0065] S250: Coat the surface of the pickled magnet with a rare earth alloy and place it in a diffusion furnace for diffusion treatment.

[0066] In this embodiment, coating and diffusion treatments are carried out using diffusion sources such as heavy rare earth alloys, which can enable rare earth elements to diffuse into the surface layer of the magnet, effectively improve the magnetic properties of the magnet, such as improving key performance indicators such as coercivity, and help to enhance the performance of the magnet in practical applications.

[0067] Specifically, the diffusion source can be a heavy rare earth alloy. For example, alloy systems such as Tb / DyHx, TbAlCu, DyAlCu, and AlCu can be used. Of course, other diffusion sources can also be used. The diffusion temperature is 800 - 950 °C, the diffusion time is 6 - 40 h, the tempering temperature is 450 - 550 °C, and the tempering time is 2 - 6 h.

[0068] S260. Grind the surface of the magnet steel after diffusion treatment.

[0069] Specifically, the grinding process is divided into rough grinding and fine grinding. The rough grinding wheel uses 100 - 160 mesh, which can quickly remove the large surplus and uneven parts on the surface of the magnet steel after diffusion treatment. The fine grinding wheel uses 200 - 300 mesh, which can further improve the surface finish, provide a good foundation for subsequent plating treatment, and ensure the dimensional accuracy and surface quality of the magnet steel.

[0070] S270. Apply a surface coating to the ground magnet steel to obtain a tile-shaped magnet steel.

[0071] In this embodiment, by coating the surface of the ground magnet steel, a protective layer can be formed, effectively blocking the contact between the external corrosive medium and the magnet steel, improving the corrosion resistance of the magnet steel, and extending its service life.

[0072] It should be noted that since the thickness of the small tile-shaped magnet steel formed body is 1 - 10 mm and it remains upright after demolding, it is easy to cause the formed body to fall over and the blank to crack when moving the graphite bearing plate. Therefore, in the forming process, this embodiment also optimizes the stacking method. For example, in some preferred embodiments, before placing the bearing plate with the tile-shaped magnet steel formed body on the bearing platform, it further includes: arranging arc-shaped partitions between the tile-shaped magnet steel formed bodies. That is to say, by separating the tile-shaped magnet steel formed bodies with partitions and making the partitions fit completely with the formed bodies, it is beneficial to increase the strength of the tile-shaped magnet steel formed bodies, avoid cracking and lodging of the formed bodies during the transfer process, and facilitate the transfer of the formed bodies.

[0073] As a further preferred solution, the thickness of the partition is preferably 0.1 - 2 mm.

[0074] In some other preferred embodiments, before placing the bearing plate with the tile-shaped magnet steel formed body on the bearing platform, the tile-shaped magnet steel formed bodies can also be stacked in a fitting manner, which can also increase the strength of the tile-shaped magnet steel formed bodies, avoid cracking and lodging of the formed bodies during the transfer process, and facilitate the transfer of the formed bodies.

[0075] As a further preferred solution, the formed bodies are fitted in a slowly pushing manner, and the fitting rate is 0.01 - 10 mm / s to ensure the consistency and stability of the fitting effect of each formed body.

[0076] The preparation method of the tile-shaped permanent magnet in this embodiment simplifies the processing flow, omits the processes of machining cutting and the tile-shaped cutting process after diffusion, and can save 20% of the material utilization rate. At the same time, through the improvement of the near-net-shape process, multi-mode forming of the small tile-shaped permanent magnet compact can be realized, which is convenient for demolding and transfer.

[0077] The present disclosure provides a demolding mechanism and a preparation method for a near-net-shape tile-shaped permanent magnet, which have the following beneficial effects compared with the prior art:

[0078] First, for the problem that the traditional forming method cannot uniformly form small tile-shaped permanent magnet products, the present disclosure adopts a near-net-shape process and a demolding mechanism to obtain a uniformly formed small tile-shaped permanent magnet compact, and can realize the uniform forming and demolding of 1-150 small samples in one mold, realizing batch production.

[0079] Second, for the problem that the quality and density of the near-net-shape permanent magnet compact are low and it cannot be grasped and transferred, in the present disclosure, the punch, the sintering plate and the powder filling device can have relative displacements, so that the tile-shaped permanent magnet compact can be directly demolded from the sintering plate without grasping, and the sintering plate can be directly transferred for sintering, solving the problem that the magnet cannot be grasped and transferred. In addition, by adding partitions or intermediate converging methods for material coding, cracking and toppling of the small tile-shaped permanent magnet compacts are avoided, which is convenient for transfer and solves the problem that small and thin compacts are prone to toppling during the transfer process.

[0080] It can be understood that the above embodiments are only exemplary embodiments adopted to illustrate the principle of the present disclosure, but the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the present disclosure.

Claims

1. A demoulding mechanism for a near-formed tile-shaped permanent magnet, characterized in that The demolding mechanism includes: a base, a firing plate, a powder filling device, and a punch; wherein, The base has a bottom plate and a top plate arranged oppositely; the firing plate, the powder filling device, and the punch are sequentially stacked between the bottom plate and the top plate in a relatively movable manner; When relative displacement occurs among the punch, the firing plate, and the powder filling device, the near-formed tile-shaped magnet compact is demolded from the firing plate.

2. The demolding mechanism according to claim 1, wherein When the tile-shaped magnet compact needs to be demolded, the punch and the firing plate move downward synchronously, and the powder filling device remains stationary.

3. The demolding mechanism according to claim 1, wherein, When the tile-shaped magnet compact needs to be demolded, the punch moves downward to the position of the powder filling device, the punch and the firing plate remain stationary, and the powder filling device moves upward.

4. The demolding mechanism according to any one of claims 1 to 3, characterized in that The powder filling device has a plurality of cavities penetrating through its thickness, and partition plates are arranged between the cavities. The partition plates are demolded from the firing plate synchronously with the tile-shaped magnet compact.

5. The demoulding mechanism according to claim 4, characterized in that, The thickness of the partition plate is 0.1 - 2 mm.

6. The demolding mechanism according to any one of claims 1 to 3, characterized in that, The demolding mechanism further includes a control module for fitting the demolded tile-shaped magnet compact.

7. The demolding mechanism according to claim 6, characterized in that The control module controls the fitting rate of the tile-shaped magnet compact to be 0.01 - 10 mm / s.

8. A preparation method of a tile-shaped permanent magnet, characterized in that, The preparation method includes the following steps: Melting Nd, Fe, and B powders to form a thin sheet alloy, and obtaining magnetic powder through hydrogenation, dehydrogenation, and jet milling treatments; Nearly forming and orienting the magnetic powder, demolding the compact using the demolding mechanism according to any one of claims 1 - 7, and obtaining a tile-shaped magnet compact on the firing plate; Placing the firing plate with the tile-shaped magnet compact on a firing platform, and obtaining a magnet through heating, heat preservation, and cooling treatments; Removing the oxide layer on the surface of the magnet; Performing coating treatment and diffusion treatment on the magnet; Performing grinding processing on the surface of the magnet; Performing surface plating on the magnet to obtain a tile-shaped magnet.

9. The preparation method according to claim 8, characterized in that The quality of the tile-shaped magnet forming body is 1-100 g, the thickness is 1-10 mm, and the density is 3.4 g / cm 3 -4.0 g / cm 3 , and the number of forming bodies per mold is 1-100 pcs.

10. The preparation method according to claim 8, characterized in that, Before placing the firing plate with the tile-shaped magnet compact on the firing platform, it further includes: Setting partition plates between the tile-shaped magnet compacts; or, Fitting the tile-shaped magnet compacts.

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