Automatic powder printing device for magnetic material sintering

Abstract

The invention relates to the technical field of magnetic part processing equipment, and discloses an automatic powder printing device for magnetic material sintering, which comprises a stock bin, the lower part of the stock bin is provided with a powder scattering box, an electromagnet, a mold cavity, a material printing platform, a piezoelectric back shore plate and a vibration table, and the inner wall of the powder scattering box is provided with a material shaking mechanism and a screen; a set of parallel electromagnets are installed on the outer side of the mold cavity and used for conducting multiple orientations on alloy powder in a magnetic field, a vibration table is installed below the piezoelectric jacking plate, and quartz crystal materials are installed on the piezoelectric jacking plate and collide with the quartz crystal materials to generate electric signals so as to achieve the weighing purpose. The equipment has the functions of filtering caked raw materials, uniformly printing powder and repeatedly orienting sintered neodymium-iron-boron powder, and solves the quality problems of incomplete powder orientation and non-uniform blank density.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic component processing equipment, in particular to an automatic powder printing device for sintering magnetic materials. Background Art

[0002] Sintering NdFeB is to orient the anisotropic magnet alloy powder in a magnetic field to form a directional structure, so that the magnet will have high magnetic properties. In the sintering process of NdFeB magnetic materials, it is necessary to go through grinding, pressing, isostatic pressing, and sintering. Before the pressing process, the alloy powder needs to be weighed and poured into the mold cavity, and then the material is shaped to make the powder evenly spread, and then magnetic orientation is performed to orient the magnetic domains.

[0003] The weighing, mold insertion and orientation processes before the above-mentioned pressing molding process are carried out step by step, and the operating process efficiency is low; and when the NdFeB blank powder is oriented during molding, the powder is placed in the mold cavity, and the poles on both sides begin to be energized to generate a magnetic field. The powder is arranged regularly under the action of the magnetic field. At present, the orientation method of sintered NdFeB powder is mostly one-time orientation, that is, the pole current is directly added from zero amperes to the current saturation point, and it rises linearly without alternating current. It is easy for a large amount of NdFeB powder to agglomerate together, resulting in incomplete orientation of the powder particles, reducing the consistency of the magnetic properties of the sintered NdFeB blank, and the blank density is uneven. Summary of the invention

[0004] In view of the problems raised in the background technology that a large amount of NdFeB powder is easily agglomerated together, the orientation of powder particles is incomplete, the density of the blank is uneven, and the process efficiency is low, etc., the present invention provides an automatic powder printing device for sintering magnetic materials, which has the advantages of filtering agglomerated raw materials, printing powder evenly, orienting sintered NdFeB powder multiple times, and having a high process efficiency, thereby solving the quality problems of incomplete powder orientation and uneven blank density raised in the above background technology.

[0005] The present invention provides the following technical solution: an automatic powder printing device for sintering magnetic materials, comprising a silo and an equipment frame, wherein the silo is fixedly installed on the top of the equipment frame through a bracket, a powder box is fixedly installed at the bottom of the silo, a screen is installed at the bottom of the powder box, and a material shaking mechanism is installed on the inner wall of the powder box, and the material shaking mechanism is used to drive the screen to vibrate to cause powder to fall.

[0006] Preferably, the material shaking mechanism is composed of a coil, a magnetic field generator and a vibration block. The coil is embedded in the inner wall of the vibration block. The vibration block is an annular thin-walled cylinder and the bottom of the vibration block is fixedly connected to the top edge of the screen. The vibration block is used to drive the screen to vibrate synchronously. The magnetic field generator is fixedly installed on the outer wall of the powder box. The magnetic field generator forms an annular magnetic field on the outer ring of the coil. The current size and change frequency of the coil are controlled by a variable resistor to make the screen shake up and down along with the vibration block.

[0007] Preferably, a mold cavity is placed below the screen, and a printing material platform is provided directly below the mold cavity. The printing material platform is a convex platform, a piezoelectric plate is embedded in the bottom end of the printing material platform, a piezoelectric top support plate is provided at the bottom below the printing material platform, a piezoelectric plate is embedded at the top of the piezoelectric top support plate, a vibration platform is provided below the piezoelectric top support plate, the top end of the flange of the printing material platform contacts the inner wall of the top end of the vibration platform to form a snap connection, support tension springs are fixedly connected to the left and right sides of the bottom end of the printing material platform, the bottom end of the support tension spring is fixedly connected to the top edge of the piezoelectric top support plate, and the bottom end of the piezoelectric top support plate is connected to the inner bottom of the vibration platform. There is a gap, and a protrusion is provided at the bottom of the vibration table, which is arranged horizontally at equal intervals. A driving motor is provided on one side of the vibration table. The driving motor realizes forward and reverse rotation by changing the direction of the input current. The driving motor is fixedly installed on the inner bottom of the equipment frame, and the output shaft of the driving motor is fixedly connected with a screw rod through a coupling. The screw rod is movably installed on the inner bottom of the equipment frame through the frame. The external thread of the screw rod is connected with a top block, and the bottom end of the top block is slidably connected to the inner bottom of the equipment frame. A boss is provided on the top of the top block, and the vibration table is lifted when the boss on the top of the top block contacts the protrusion at the bottom end of the vibration table.

[0008] Preferably, contact switches are installed on both sides of the vibration table, and electromagnets are installed on both sides of the mold cavity. The electromagnets on the left and right sides are energized to generate magnetic fields, and are arranged in opposite directions to form a horizontal magnetic field. The electromagnet is fixedly installed on the top of the equipment frame, and the contact switch is triggered when the top block moves to the leftmost end or the rightmost end. When the contact switch is closed, the electromagnet is energized to generate a horizontal magnetic field.

[0009] Preferably, under the action of the return force of the supporting tension spring, the piezoelectric plate at the bottom of the printing platform collides with the piezoelectric plate at the top of the piezoelectric top support plate to produce a piezoelectric effect and generate an instantaneous voltage. When the voltage reaches a preset value, the electromagnet, drive motor and material shaking mechanism are turned off through the PLC controller.

[0010] The present invention has the following beneficial effects: 1. The present invention can effectively improve the efficiency of NdFeB powder entering the mold by screen shaking feeding and cavity vibration whole material.

[0011] 2. The present invention sets a printing platform and a piezoelectric top support plate, and adds a quartz crystal piezoelectric plate under the condition of impact vibration to achieve weighing and timely control feedback to stop unloading, thereby integrating the original weighing, mold feeding, and powder leveling processes to improve process efficiency and process quality.

[0012] 3. The present invention achieves layer-by-layer orientation of the powder in the mold cavity by adding an electromagnet outside the mold cavity and cooperating with the top block to intermittently open and close the contact switch, so that the powder in the mold cavity is basically magnetically oriented when the feeding is completed, effectively ensuring the process quality of the magnetic orientation before the subsequent pressing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 For the present invention Figure 1 Sectional view at AA; Figure 3 For the present invention Figure 1 A partial enlarged schematic diagram of the structure at B in the middle; Figure 4 For the present invention Figure 1 A partial enlarged schematic diagram of the structure at point C in the middle.

[0014] In the figure: 1. silo; 2. powder box; 3. material shaking mechanism; 31. coil; 32. magnetic field generator; 33. vibration block; 4. screen; 5. electromagnet; 6. mold cavity; 7. printing platform; 8. piezoelectric top support plate; 9. support tension spring; 10. contact switch; 11. vibration table; 12. top block; 13. screw rod; 14. drive motor; 15. equipment frame. Implementation

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] See also Figure 1-Figure 4 An automatic powder printing device for sintering magnetic materials includes a silo 1 and an equipment frame 15. The silo 1 is fixedly installed on the top of the equipment frame 15 through a bracket. A powder box 2 is fixedly installed at the lower part of the silo 1. The alloy powder in the silo 1 enters the powder box 2 through a discharge port. A screen 4 is provided at the bottom of the powder box 2. The screen 4 is used to screen the NdFeB powder to prevent the compacted powder from directly entering the subsequent mold.

[0017] A material shaking mechanism 3 is installed on the inner wall of the powder box 2. The material shaking mechanism 3 is composed of a coil 31, a magnetic field generator 32 and a vibration block 33. The coil 31 is embedded in the inner wall of the vibration block 33. The vibration block 33 is an annular thin-walled tube and the bottom of the vibration block 33 is fixedly connected to the top edge of the screen 4. The vibration block 33 is used to drive the screen 4 to vibrate synchronously. The magnetic field generator 32 is fixedly installed on the outer wall of the powder box 2. The magnetic field generator 32 forms an annular magnetic field on the outer circle of the coil 31. The current size and change frequency of the coil 31 are controlled by a variable resistor to make the screen 4 shake up and down along with the vibration block 33, so as to realize the screening of neodymium iron boron powder. A mold cavity 6 is placed below the screen 4 of the material shaking mechanism. Electromagnets 5 are provided on the left and right sides of the mold cavity 6. The electromagnets 5 on the left and right sides are energized to generate a magnetic field, and are arranged oppositely to each other to form a horizontal magnetic field. The electromagnet 5 is fixedly installed on the top of the equipment frame 15. A printing platform 7 is provided directly below the mold cavity 6. The printing platform 7 is a convex platform. A piezoelectric plate is embedded at the bottom of the printing platform 7. A piezoelectric top support plate 8 is provided at the bottom of the printing platform 7. The piezoelectric top support plate 8 is composed of a piezoelectric plate at the top and four support columns at the bottom, wherein the piezoelectric plate is composed of an upper piezoelectric part and a lower insulating part. The four support columns are used to suspend the piezoelectric plate. The bottom ends of the four support columns are fixedly installed on the inner bottom of the equipment frame 15. A vibration table 11 is provided below the piezoelectric top support plate 8. The vibration table 11 is a rectangular hollow groove with an opening at the top. The top of the flange of the printing platform 7 contacts the inner wall of the top of the vibration table 11 to form a snap connection. Support tension springs 9 are fixedly connected to the left and right sides of the bottom end of the printing platform 7. The bottom end of the support tension spring 9 is fixedly connected to the top edge of the piezoelectric top support plate 8. Thus, the empty mold cavity 6 is placed on the top of the printing platform 7, and the piezoelectric plate at the bottom of the printing platform 7 contacts the piezoelectric plate at the top of the piezoelectric top support plate 8. At this time, there is a gap between the bottom of the piezoelectric top support plate 8 and the inner bottom of the vibration table 11. The return force of the support spring 9 is used to press the printing platform 7 and the piezoelectric top support plate 8 tightly into contact.

[0018] A protrusion is provided at the bottom of the vibration table 11, and the protrusions are arranged horizontally at equal intervals. Contact switches 10 are provided on the left and right sides of the vibration table 11. A drive motor 14 is provided on one side of the vibration table 11. When different contact switches 10 are turned on, the drive motor 14 changes the direction of the input current to achieve forward and reverse rotation. The drive motor 14 is fixedly installed on the inner bottom of the equipment frame 15. The output shaft of the drive motor 14 is fixedly connected to a screw rod 13 through a coupling. The screw rod 13 is movably installed on the inner bottom of the equipment frame 15 through the frame. The external thread of the screw rod 13 is connected to a top block 12. The bottom end of the top block 12 is slidably connected to the inner bottom of the equipment frame 15. A boss is provided on the top of the top block 12. When the boss at the top of the top block 12 contacts the protrusion at the bottom of the vibration table 11, the vibration table 11 is lifted.

[0019] The driving motor 14 drives the screw rod 13 to rotate forward and backward through the coupling, and the screw rod 13 drives the top block 12 to move back and forth left and right. When the top block 12 moves to the leftmost end or the rightmost end, the contact switch 10 is triggered. The contact switch 10 is composed of a reset spring and a circuit switch. When the contact switch 10 is closed, the electromagnet 5 is triggered to generate a horizontal magnetic field, and the NdFeB powder in the mold cavity 6 is oriented once. When the top block 12 leaves the contact switch 10, the electromagnet 5 is de-energized. During the left and right movement of the boss at the top of the top block 12, it intermittently collides with the protrusion of the vibration table 11, driving the piezoelectric top support plate printing platform 7 to vibrate up and down, so that the NdFeB powder in the mold cavity 6 is evenly distributed. The piezoelectric top support plate 8 and the piezoelectric plate on the printing platform 7 are made of quartz crystal materials. Under the action of the return force of the supporting tension spring 9, the piezoelectric plate at the bottom of the printing platform 7 collides with the piezoelectric plate at the top of the piezoelectric top support plate 8 to generate a piezoelectric effect and generate an instantaneous voltage. The piezoelectric voltage of the piezoelectric top support plate is generated by the return force of the supporting tension spring 9 of a fixed size and the gravity of the newly added alloy powder in the mold cavity 6 and is proportional to the piezoelectric voltage. The electrical signal (voltage or current) measured by the signal amplification device can be converted into the weight increase of the NdFeB powder in the mold cavity 6 to achieve the weighing purpose. When the weight of the NdFeB powder in the mold cavity 6 reaches the set value, the electromagnet 5, the drive motor 14 and the material shaking mechanism 3 are turned off by the PLC controller.

[0020] Thus, after the NdFeB powder is vibrated and screened by the screen 4, it falls into the mold cavity 6 more evenly. The mold cavity 6 is affected by the vibration of the printing platform 7, which further improves the paving flatness of the NdFeB powder in the mold cavity 6. After the feeding reaches the preset weight, the feeding can be stopped in time. In addition, while the powder is spread layer by layer in the mold cavity 6, the electromagnet 5 performs pre-orientation treatment on the powder in the mold cavity 6 to ensure that the magnetic orientation treatment before the subsequent pressing process can be carried out efficiently and reduce the agglomeration phenomenon. That is, the weighing of the powder, the feeding of the mold cavity 6, the paving of the powder in the mold cavity 6, and the pre-orientation treatment are comprehensively and synchronously processed, which effectively saves the process flow and improves the process efficiency and the quality of the subsequent process.

[0021] The method of use (working principle) of the present invention is as follows: when working, the material shaking mechanism 3 is first started, and the magnetic field generator 32 forms a circular magnetic field around the coil 31. The current intensity of the coil 31 changes with the time period. Under the action of the magnetic field, the coil 31 generates an upward thrust that changes with the current size, driving the vibration block 33 to vibrate up and down. The screen 4 and the vibration block 33 are fixedly connected. The screen 4 reciprocates under the upward thrust of the material shaking mechanism 3, and the neodymium iron boron powder is shaken into the mold cavity 6. Then the driving motor 14 starts to rotate forward and reverse, and drives the screw rod 13 to rotate forward and reverse through the gear. The screw rod 13 drives the top block 12 to move left and right. When the top block 12 moves to the leftmost or rightmost end The contact switch 10 is triggered. When the contact switch 10 is closed, the electromagnet 5 is triggered to generate a magnetic field, and the NdFeB powder in the mold cavity 6 is oriented once. During the left and right movement of the boss of the top block 12, it collides with the convexity of the vibration table 11, driving the piezoelectric top support plate 8 and the printing platform 7 to vibrate up and down to evenly distribute the NdFeB powder in the mold cavity 6. The vibration of the printing platform 7 and the piezoelectric top support plate 8 collides with the quartz crystal material to generate an electrical signal, which can be converted into the weight of the NdFeB powder in the mold cavity 6 through the signal amplification device to achieve the weighing effect. When the weight of the NdFeB powder in the mold cavity 6 reaches the set value, the PLC control system turns off the electromagnet 5, the drive motor 14, and the material shaking mechanism 3.

Claims

1. An automatic powder printing device for sintering magnetic materials, comprising a silo (1) and a device frame (15), wherein the silo (1) is fixedly mounted on the top of the device frame (15) through a bracket, and a powder sprinkling box (2) is fixedly mounted on the lower part of the silo (1), characterized in that: A screen (4) is installed at the bottom of the powder sprinkling box (2), and a material shaking mechanism (3) is installed on the inner wall of the powder sprinkling box (2), wherein the material shaking mechanism (3) is used to drive the screen (4) to vibrate and cause powder to fall.

2. The automatic powder printing device for sintering magnetic materials according to claim 1, characterized in that: The material shaking mechanism (3) is composed of a coil (31), a magnetic field generator (32) and a vibration block (33); the coil (31) is embedded in the inner wall of the vibration block (33); the vibration block (33) is an annular thin-walled cylinder and the bottom of the vibration block (33) is fixedly connected to the top edge of the screen (4); the vibration block (33) is used to drive the screen (4) to vibrate synchronously; the magnetic field generator (32) is fixedly mounted on the outer wall of the powder box (2); the magnetic field generator (32) forms an annular magnetic field on the outer ring of the coil (31); and the current size and change frequency of the coil (31) are controlled by a variable resistor to cause the screen (4) to shake up and down along with the vibration block (33).

3. The automatic powder printing device for sintering magnetic materials according to claim 2, characterized in that: A mold cavity (6) is placed below the screen (4), and a printing platform (7) is provided directly below the mold cavity (6). The printing platform (7) is a convex platform, and a piezoelectric plate is embedded in the bottom end of the printing platform (7). A piezoelectric top support plate (8) is provided at the bottom of the printing platform (7), and a piezoelectric plate is embedded at the top of the piezoelectric top support plate (8). A vibration platform (11) is provided below the piezoelectric top support plate (8). The top of the flange of the printing platform (7) contacts the inner wall of the top of the vibration platform (11) to form a snap connection. Support tension springs (9) are fixedly connected to the left and right sides of the bottom of the printing platform (7), and the bottom end of the support tension spring (9) is fixedly connected to the top edge of the piezoelectric top support plate (8). There is a gap between the bottom end of the piezoelectric top support plate (8) and the inner bottom of the vibration platform (11). The bottom of the vibration table (11) is provided with protrusions, which are arranged horizontally at equal intervals. A driving motor (14) is provided on one side of the vibration table (11). The driving motor (14) realizes forward and reverse rotation by changing the direction of the input current. The driving motor (14) is fixedly installed on the inner bottom of the equipment frame (15). The output shaft of the driving motor (14) is fixedly connected to a screw rod (13) through a coupling. The screw rod (13) is movably installed on the inner bottom of the equipment frame (15) through the frame. The external thread of the screw rod (13) is connected to a top block (12). The bottom end of the top block (12) is slidably connected to the inner bottom of the equipment frame (15). The top end of the top block (12) is provided with a boss. When the boss at the top end of the top block (12) contacts the protrusion at the bottom end of the vibration table (11), the vibration table (11) is lifted.

4. The automatic powder printing device for sintering magnetic materials according to claim 3, characterized in that: The left and right sides of the vibration table (11) are both provided with contact switches (10), and the left and right sides of the mold cavity (6) are both provided with electromagnets (5). The electromagnets (5) on the left and right sides are energized to generate magnetic fields, and are arranged oppositely to each other to form a horizontal magnetic field. The electromagnets (5) are fixedly mounted on the top of the equipment frame (15). When the top block (12) moves to the leftmost end or the rightmost end, the contact switch (10) is triggered. When the contact switch (10) is closed, the electromagnets (5) are triggered to be energized to generate a horizontal magnetic field.

5. The automatic powder printing device for sintering magnetic materials according to claim 4, characterized in that: Under the pull-back force of the supporting tension spring (9), the piezoelectric plate at the bottom of the printing platform (7) collides with the piezoelectric plate at the top of the piezoelectric top support plate (8) to generate a piezoelectric effect and generate an instantaneous voltage. When the voltage reaches a preset value, the electromagnet (5), the drive motor (14) and the material shaking mechanism (3) are turned off through the PLC controller.

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