Radiation ring magnetic field press forming method

Abstract

The application discloses a radiation ring magnetic field compression molding method, comprising the following steps: S1: moving a core rod to a position where the core rod is 10-20 mm lower than a mold, and spraying a mold cavity with a release agent by a release agent spraying device; S2: filling a quantitative neodymium-iron-boron powder into the mold cavity by a feeding device, then driving a lower die punch to move down a stroke L1 mm by a lower driving member, and filling the quantitative neodymium-iron-boron powder into the mold cavity by the feeding device after each time the lower die punch moves down the stroke L1 mm; S3: moving a upper die punch down into the mold cavity to pre-press the neodymium-iron-boron powder; S4: first, electrifying a upper electromagnet assembly fixed to a upper guide plate and a lower electromagnet assembly fixed to a lower guide plate for T1 min; then, moving the upper die punch down, driving the core rod to move down synchronously with the upper die punch by a core pulling electric cylinder, and driving the lower die punch to move up by the lower driving member until compression is completed; S5: moving the upper die punch up by a distance L2 mm and keeping for a set time length; and S6: compression molding, so that the density of the neodymium-iron-boron powder is uniform.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of neodymium iron boron processing, and particularly relates to a radiation ring magnetic field compression molding method. BACKGROUND

[0002] The magnetic field forming press mainly comprises a sealed frame, a powder weighing device, a feeding device and a forming device are arranged in the frame, the neodymium iron boron powder first enters the powder weighing device through a barrel, the powder weighing device weighs a certain amount of neodymium iron boron powder, then the neodymium iron boron powder is loaded into the feeding device, finally the feeding device pushes the feeding device to the forming device, and the neodymium iron boron powder is loaded into the forming mold, and then the neodymium iron boron powder is compression molded.

[0003] The powder weighing device is an important component of the neodymium iron boron powder magnetic field forming press, and the feeding process of the neodymium iron boron forming press comprises: the neodymium iron boron powder first enters the weighing device through the barrel, the weighing device weighs a certain amount of neodymium iron boron powder, then the neodymium iron boron powder is loaded into the powder feeding device, finally the powder feeding device pushes the powder feeding device to the forming mold, and the neodymium iron boron powder is loaded into the forming mold.

[0004] The existing magnetic field forming press fills the neodymium iron boron powder into the mold cavity through the powder feeding device at one time, but due to the small gap of the annular cavity of the mold cavity, the neodymium iron boron powder will adhere to the wall of the annular cavity and affect the uniform sinking of the neodymium iron boron powder in the mold cavity, so that the density distribution of the neodymium iron boron powder in the mold cavity is not uniform, thereby affecting the yield of the neodymium iron boron magnet, in addition, the flowability of the neodymium iron boron powder in the narrow annular cavity is poor, and the bridging phenomenon will occur, so that the density of part of the mold cavity is too high, and the density of part of the mold cavity is low, so that the density distribution of the neodymium iron boron powder in the mold cavity is not uniform, thereby affecting the yield of the neodymium iron boron magnet. SUMMARY

[0005] The purpose of the present application is to provide a radiation ring magnetic field compression molding method, which can ensure the uniform density of the neodymium iron boron powder in the mold cavity by intermittent downward movement of the lower die punch and batch feeding of the neodymium iron boron powder, thereby ensuring the yield of the neodymium iron boron magnet.

[0006] The above technical purpose of the present application is realized by the following technical scheme: a radiation ring magnetic field compression molding method, comprising the following steps:

[0007] S1: spraying a release agent: the core rod is driven to move to a position where the upper end face of the core rod is 10-20mm lower than the upper end face of the mold by the core pulling electric cylinder, and the release agent spraying device sprays the release agent to the mold cavity;

[0008] S2: filling neodymium iron boron powder: first, the core pulling cylinder drives the core rod to move up to the position where the upper end face of the core rod is not lower than the upper end face of the mold, then the lower driving part drives the lower die punch to move to the position where the upper end face of the lower die punch is L1 mm lower than the upper end face of the mold, the feeding device fills a certain amount of neodymium iron boron powder into the mold cavity, then the lower driving part drives the lower die punch to move down by a stroke of L1 mm, after the lower die punch moves down by a stroke of L1 mm each time, the feeding device gradually fills a certain amount of neodymium iron boron powder into the mold cavity, until the filling of neodymium iron boron powder is completed;

[0009] S3: pre-pressing of the upper die punch: the core rod and the lower die punch remain stationary, the upper driving part drives the upper die punch to move down into the mold cavity to pre-press the neodymium iron boron powder;

[0010] S4: press forming: first, the upper die punch, the lower die punch and the core rod remain stationary, the upper electromagnet assembly fixed to the upper guide plate and the lower electromagnet assembly fixed to the lower guide plate are energized for T1 min; then the upper driving part drives the upper die punch to move down, the core pulling cylinder drives the core rod to move down synchronously with the upper die punch, the lower driving part drives the lower die punch to move up, thereby pressing the neodymium iron boron powder in the mold cavity for T2 min until the pressing is completed;

[0011] S5: stress release: the lower die punch and the core rod remain stationary, the upper driving part drives the upper die punch to move up by a distance of L2 mm and remain stationary for a set period of time to release the stress of the formed neodymium iron boron magnetic ring;

[0012] S6: demolding: the upper driving part drives the upper die punch to move up, the lower driving part drives the lower die punch to move up, the core pulling cylinder drives the core rod to move up, thereby demolding the formed neodymium iron boron magnetic ring.

[0013] Further, in step S2, the upper end face of the lower die punch is L1 mm lower than the upper end face of the mold, where 10≤L1≤20.

[0014] Further, in step S3, when the upper die punch is pre-pressed, the lower end face of the upper die punch extends into the mold cavity by 4-6 mm.

[0015] Further, in step S5, the upper driving part drives the upper die punch to move up by a distance of L2 mm, where 0.5≤L2≤2.

[0016] Further, in step S5, the upper driving part drives the upper die punch to move up by L2 mm for 1-2 seconds.

[0017] Further, in step S6, after the lower die punch moves up to the position where the upper end face of the lower die punch is flush with the upper end face of the mold, the core pulling cylinder drives the core rod to move down into the mold cavity.

[0018] Further, in step S2, the core-pulling cylinder drives the core rod to move upward to the position where the upper end surface of the core rod is flush with the upper end surface of the mold, so that the feeding device can move back and forth along the mold, and each time the feeding device moves, a certain amount of neodymium iron boron powder is filled into the mold cavity.

[0019] In summary, the present application has the following advantages:

[0020] 1. The present application can ensure the uniform density of neodymium iron boron powder in the mold cavity by intermittent downward movement of the lower punch and batch feeding of neodymium iron boron powder, thereby ensuring the yield of neodymium iron boron magnets.

[0021] 2. Before pressing the neodymium iron boron powder, the upper and lower electromagnet assemblies are energized for a set time, and after the upper and lower electromagnet assemblies are energized, the upper and lower poles are pressed after a certain time delay, thereby ensuring more uniform magnetization and better magnetization effect. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of the present application.

[0023] Figure 2 is a schematic diagram of the internal structure of the mold cavity of the present application.

[0024] Figure 3 is a schematic diagram of the Figure 2 of the present application.

[0025] In the figure: 10, rack; 20, upper driving part; 21, upper guide plate; 22, upper electromagnet assembly; 221, upper electromagnet coil; 222, upper pole; 223, upper pole head; 23, upper punch; 231, blind groove; 30, lower driving part; 31, lower guide plate; 311, avoidance channel; 32, lower electromagnet assembly; 321, lower electromagnet coil; 322, lower pole; 323, lower pole head; 33, lower punch; 40, core-pulling cylinder; 41, core rod; 50, magnetic guide plate; 51, mold; 60, feeding device. DETAILED DESCRIPTION

[0026] The present application will be further described below with reference to the accompanying drawings.

[0027] As Figures 1-3As shown, a radiation ring magnetic field compression molding method includes a rack 10, a mold 51 arranged in the middle of the rack 10, an upper guide plate 21 arranged at the upper end of the mold 51, an upper die punch 23 and an upper electromagnet assembly 22 fixed at the lower end of the upper guide plate 21, an upper driving member 20 for driving the upper guide plate 21 to ascend and descend, a lower guide plate 31 arranged at the lower end of the mold 51, a lower die punch 33 and a lower electromagnet assembly 32 fixed at the upper end of the lower guide plate 31, a lower driving member 30 for driving the lower guide plate 31 to ascend and descend, a core-pulling cylinder 40 arranged at the bottom of the rack 10, a core rod 41 connected to the core-pulling cylinder 40, a feeding device 60 capable of sliding along the rack 10, and a release agent spraying device arranged at the front end of the feeding device 60, and the mold 51 is provided with a mold cavity,

[0028] The radiation ring magnetic field compression molding method includes the following steps:

[0029] S1: Spray release agent: the core-pulling cylinder 40 drives the core rod 41 to move to a position where the upper end surface of the core rod 41 is 10-20mm lower than the upper end surface of the mold 51, and the release agent spraying device sprays release agent into the mold cavity;

[0030] S2: Fill neodymium iron boron powder: first, the core-pulling cylinder 40 drives the core rod 41 to move upward to a position where the upper end surface of the core rod 41 is not lower than the upper end surface of the mold 51, then the lower driving member 30 drives the lower die punch 33 to move to a position where the upper end surface of the lower die punch 33 is L1mm lower than the upper end surface of the mold 51, the feeding device 60 fills a certain amount of neodymium iron boron powder into the mold cavity, then the lower driving member 30 drives the lower die punch 33 to move downward by a stroke of L1mm, after each time the lower die punch 33 moves downward by a stroke of L1mm, the feeding device 60 gradually fills a certain amount of neodymium iron boron powder into the mold cavity, until the filling of neodymium iron boron powder is completed;

[0031] S3: Pre-press the upper die punch 23: the core rod 41 and the lower die punch 33 remain stationary, and the upper driving member 20 drives the upper die punch 23 to move downward into the mold cavity to pre-press the neodymium iron boron powder;

[0032] S4: Compression molding: first, the upper die punch 23, the lower die punch 33 and the core rod 41 remain stationary, and the upper electromagnet assembly 22 fixed to the upper guide plate 21 and the lower electromagnet assembly 32 fixed to the lower guide plate 31 are powered for T1min; then the upper driving member 20 drives the upper die punch 23 to move downward, the core-pulling cylinder 40 drives the core rod 41 to move downward synchronously with the upper die punch 23, and the lower driving member 30 drives the lower die punch 33 to move upward, thereby compressing the neodymium iron boron powder in the mold cavity for T2min, until the compression is completed;

[0033] S5: Stress release: the lower die punch 33 and the core rod 41 remain stationary, the upper driving member 20 drives the upper die punch 23 to move upward by a distance of L2mm and remain stationary for a certain period of time to release the stress of the formed neodymium iron boron magnetic ring;

[0034] S6: demolding: the upper driving member 20 drives the upper die punch 23 to move upward, the lower driving member 30 drives the lower die punch 33 to move upward, and the core pulling cylinder 40 drives the core rod 41 to move upward, thereby demolding the formed Nd-Fe-B magnetic ring.

[0035] Before or during step S1, a set amount of Nd-Fe-B powder is weighed by a powder weighing device, and after the powder weighing device completes the weighing, the Nd-Fe-B powder is transferred into the powder box of the feeding device 60.

[0036] The mold 51 is a female mold, which is fixedly installed in the middle of the forming press through the magnetic conducting plate 50. The magnetic conducting plate 50 has the following functions: 1. It constitutes a magnetic circuit when magnetizing, reduces magnetic leakage, and improves the magnetic field strength of the mold cavity; 2. It is used for fixing the female mold and improving the pressing precision.

[0037] In step S1, the core pulling cylinder 40 drives the core rod 41 to sink to a position 10-20 mm below the upper end surface of the mold 51. The purpose is to make the demolding agent fall more uniformly.

[0038] In some embodiments, in step S2, the upper end surface of the lower die punch 33 is L1 mm below the upper end surface of the mold 51, where 10≤L1≤20.

[0039] In some embodiments, in step S2, the feeding device 60 reciprocally moves along the mold 51 to discharge the Nd-Fe-B powder. Specifically, the feeding device 60 moves once and discharges a certain amount of Nd-Fe-B powder each time the lower driving member 30 drives the lower die punch 33 to move downward by L1 mm. The feeding device 60 moves once and pours a certain amount of Nd-Fe-B powder each time the lower die punch 33 moves downward intermittently, and the Nd-Fe-B powder transferred into the powder box of the feeding device 60 after the powder weighing device weighs the powder is discharged in batches in the above process. This can ensure the uniform density of the Nd-Fe-B powder in the mold cavity, thereby ensuring the yield of the Nd-Fe-B magnet.

[0040] In some embodiments, in step S3, when pre-pressing, the lower end surface of the upper die punch 23 extends into the mold cavity by 4-6 mm, preferably 5 mm.

[0041] In some embodiments, in step S4, the core rod 41 and the lower die punch 33 remain stationary during the process of the upper driving member 20 driving the upper die punch 23 to pre-press.

[0042] The pre-pressing step before pressing can make the density of the Nd-Fe-B powder in the mold cavity more uniform, thereby improving the yield of the Nd-Fe-B magnetic ring.

[0043] In some embodiments, in step S5, the upper driving member 20 drives the upper die punch 23 to move upward by a distance L2 mm, wherein 0.5≤L2≤2. In step S5, the upper driving member 20 drives the upper die punch 23 to move upward by L2 mm for 1-2 seconds. Through the above setting, the stress of the pressed neodymium iron boron magnetic ring can be effectively released.

[0044] In some embodiments, in step S6, the upper driving member 20, the lower driving member 30 and the core pulling cylinder 40 synchronously drive the corresponding upper die punch 23, the lower die punch 33 and the core rod 41 to move upward, and in step S6, when the lower die punch 33 moves to the position that the upper end face of the lower die punch 33 is flush with the upper end face of the mold 51, the core pulling cylinder 40 drives the core rod 41 to move downward into the mold cavity.

[0045] In some embodiments, in step S2, the core pulling cylinder 40 drives the core rod 41 to move upward to the position that the upper end face of the core rod 41 is flush with the upper end face of the mold 51, so that the feeding device 60 can reciprocate along the mold 51, and each time the feeding device 60 moves, it fills a certain amount of neodymium iron boron powder into the mold cavity.

[0046] In some embodiments, the upper electromagnet assembly 22 includes an upper pole column 222 fixed to the upper guide plate 21, an upper pole head 223 fixed to the lower end of the upper pole column 222, and an upper electromagnetic coil 221 fixed to the outer periphery of the upper pole column 222, the upper die punch 23 is fixed to the lower end of the upper pole head 223, and the upper driving member 20 is fixedly connected to the upper guide plate 21, the lower electromagnet assembly 32 includes a lower pole column 322 fixed to the lower guide plate 31, a lower pole head 323 fixed to the upper end of the lower pole column 322, and a lower electromagnetic coil 321 fixed to the outer periphery of the lower pole column 322, the lower die punch 33 is fixed to the upper end of the lower pole head 323, and the lower driving member 30 is fixedly connected to the lower guide plate 31, the lower guide plate 31, the lower pole column 322, the lower pole head 323 and the lower die punch 33 are provided with a avoiding passage for the core rod 41 to pass through.

[0047] In some embodiments, the lower end face of the upper pole head 223 is provided with a blind groove 231 matched with the core rod 41, and the depth of the blind groove 231 is 5-6 mm, specifically, the depth of the blind groove 231 is slightly greater than 5 mm, through the setting of the blind groove 231, not only the positioning function can be achieved, but also the function of guiding the magnetic force line can be achieved.

[0048] In some embodiments, the upper driving member 20 and the lower driving member 30 are electric cylinders, the lower guide plate 31 is provided with a guide hole in sliding fit with a guide post, the lower electromagnet assembly 32 is fixedly installed at the upper end of the lower guide plate 31, and specifically, the upper driving member 20 is fixedly installed at the top of the rack 10, the output end of the upper driving member 20 is fixedly connected to the upper guide plate 21, the rack 10 is provided with guide posts around, the upper guide plate 21 is provided with a guide hole in sliding fit with the guide posts, and the upper electromagnet assembly 22 is fixedly installed at the lower end of the upper guide plate 21. The lower driving member 30 is a left lower electric cylinder and a right lower electric cylinder fixedly arranged at the bottom of the rack 10. By arranging two groups of electric cylinders, the two groups of electric cylinders can improve the stability of moving the lower guide plate 31 under the premise of avoiding the core-pulling cylinder 40.

[0049] The core-pulling cylinder 40 is fixedly arranged at the middle of the lower end of the rack 10, and the output end of the core-pulling cylinder 40 is fixedly connected with the core rod 41.

[0050] Before pressing the Nd-Fe-B powder, the upper electromagnet assembly 22 and the lower electromagnet assembly 32 are powered for a set time, that is, after the upper electromagnet assembly 22 and the lower electromagnet assembly 32 are powered, the upper pole 222 and the lower pole 322 are pressed after a delay, so as to ensure more uniform magnetization and better magnetization effect.

[0051] When the upper electromagnet coil 221 and the lower electromagnet coil 321 are powered, the upper electromagnet coil 221 and the lower electromagnet coil 321 are repulsively arranged, for example, when the upper end of the upper electromagnet coil 221 is N-pole and the lower end is S-pole, at this time, the upper end of the lower electromagnet coil 321 is S-pole and the lower end is N-pole; similarly, when the upper end of the upper electromagnet coil 221 is S-pole and the lower end is N-pole, at this time, the upper end of the lower electromagnet coil 321 is N-pole and the lower end is S-pole, and the magnetic lines of the upper electromagnet coil 221 and the lower electromagnet coil 321 form a repulsive radiation field in the middle of the mold 51.

[0052] The above is only a preferred embodiment of the present application, and equivalent changes or modifications made according to the structure, features and principles described in the patent application scope of the present application are included in the patent application scope of the present application.

Claims

1. A radiation ring magnetic field press forming method, characterized by: The method comprises the following steps: S1: spraying release agent: the core pulling cylinder (40) drives the core rod (41) to move to a position where the upper end surface of the core rod (41) is 10-20 mm lower than the upper end surface of the mold (51), and the release agent spraying device sprays release agent into the mold cavity; S2: filling neodymium iron boron powder: first, the core pulling cylinder (40) drives the core rod (41) to move upward to a position where the upper end surface of the core rod (41) is not lower than the upper end surface of the mold (51), then the lower driving part (30) drives the lower die punch (33) to move to a position where the upper end surface of the lower die punch (33) is L1 mm lower than the upper end surface of the mold (51), the feeding device (60) fills a certain amount of neodymium iron boron powder into the mold cavity, then the lower driving part (30) drives the lower die punch (33) to move downward by a stroke of L1 mm, after each time the lower die punch (33) moves downward by a stroke of L1 mm, the feeding device (60) gradually fills a certain amount of neodymium iron boron powder into the mold cavity, until the filling of neodymium iron boron powder is completed; the core pulling cylinder (40) drives the core rod (41) to move upward to a position where the upper end surface of the core rod (41) is flush with the upper end surface of the mold (51), so that the feeding device (60) can reciprocate along the mold (51), and each time the feeding device (60) moves, it fills a certain amount of neodymium iron boron powder into the mold cavity; S3: pre-pressing of the upper die punch (23): the core rod (41) and the lower die punch (33) remain stationary, and the upper driving part (20) drives the upper die punch (23) to move downward into the mold cavity to pre-press the neodymium iron boron powder; S4: compression molding: first, the upper die punch (23), the lower die punch (33) and the core rod (41) remain stationary, and the upper electromagnet assembly (22) fixed to the upper guide plate (21) and the lower electromagnet assembly (32) fixed to the lower guide plate (31) are energized for T1 min; then, the upper driving part (20) drives the upper die punch (23) to move downward, the core pulling cylinder (40) drives the core rod (41) to move downward synchronously with the upper die punch (23), and the lower driving part (30) drives the lower die punch (33) to move upward, thereby compressing the neodymium iron boron powder in the mold cavity for T2 min, until the compression is completed; S5: stress release: the lower die punch (33) and the core rod (41) remain stationary, and the upper driving part (20) drives the upper die punch (23) to move upward by a distance of L2 mm and remain stationary for a certain period of time to release the stress of the formed neodymium iron boron magnetic ring; S6: demolding: the upper driving part (20) drives the upper die punch (23) to move upward, the lower driving part (30) drives the lower die punch (33) to move upward, and the core pulling cylinder (40) drives the core rod (41) to move upward, thereby demolding the formed neodymium iron boron magnetic ring.

2. A method of radial ring magnetic field press forming according to claim 1, characterized in that: In step S2, the upper end surface of the lower die punch (33) is L1 mm lower than the upper end surface of the mold (51), and 10≤L1≤20.

3. A method of field compaction according to claim 2, wherein: In step S3, when pre-pressing, the lower end surface of the upper die punch (23) extends into the mold cavity by 4-6 mm.

4. A method of field compaction according to claim 1, wherein: In step S5, the upper driving part (20) drives the upper die punch (23) to move upward by a distance of L2 mm, and 0.5≤L2≤2.

5. A method of field compaction according to claim 4, wherein: In step S5, the upper driving part (20) drives the upper die punch (23) to move upward by a distance of L2 mm for 1-2 seconds.

6. A method of field compaction according to claim 1, wherein: In step S6, when the lower die punch (33) is moved up to the upper end surface of the die (51) flush, the core pulling cylinder (40) drives the core rod (41) to move down into the mold cavity.

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