Magnetic steel processing method and magnetic steel processing device

Abstract

The application discloses a magnetic steel processing method and device, and belongs to the technical field of laser processing, and comprises the following contents: S1. The temperature control processing table has a temperature transmission area for cooling, the magnetic steel is fixed on the temperature control processing table and is attached to the temperature transmission area, so that the magnetic steel is cooled; wherein the temperature of the temperature transmission area is less than the Curie temperature of the magnetic steel and does not affect the toughness of the material; S2. The cutting area of the magnetic steel is placed in an external magnetic field, and a laser cutting head is started to cut the magnetic steel, wherein the magnetic field strength of the external magnetic field is greater than or equal to the coercive force of the magnetic steel; S3. The cutting end point is reached, and the laser cutting head is turned off; after the cutting seam is solidified, the temperature control processing table and the external magnetic field stop working, the power supply is turned off, and the cutting is completed; the external magnetic field can supplement the magnetic force in the magnetic steel, so that the problem of excessive loss of magnetism in the processing process is avoided; through the cooling of the magnetic steel, the size of the thermal influence area is reduced, the influence on the magnetism of the magnetic steel is reduced, and the processing method and the processing device can be suitable for the magnetic steel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser processing, in particular to a magnetic steel processing method and a magnetic steel processing device. BACKGROUND

[0002] The current mainstream magnetic steels include aluminum-nickel-cobalt magnetic steel, ferrite magnetic steel, and neodymium-iron-boron magnetic steel, etc. The metal components of these magnetic steels are different, the magnetic properties are different, and thus the uses are different. These magnetic steels are mainly used in various sensor, instrument, electronic, electromechanical, medical, teaching, automobile, aviation, military technology, etc. fields.

[0003] At present, the production processes of magnetic steels mainly include sintering, bonding and casting. However, these methods only manufacture multiple pieces of materials with the same function through a mold, and subsequent post-processing is required through surface processing or electroplating treatment. For special small-scale applications, only the processing methods of wire cutting or grinding are available at present. Since the hardness of the magnetic steel is extremely high, the wire cutting can only process thin plates. The grinding method is time-consuming and has low production efficiency.

[0004] Due to the particularity of the magnetic steel, the Curie temperature of the magnetic steel is generally between 400℃ and 800℃. When the temperature of the magnetic steel exceeds the Curie temperature, the molecular thermal motion in the magnetic steel causes irreversible disorder of the magnetic dipole moment arrangement, resulting in rapid decline of the magnetic property of the magnetic steel, and the process is irreversible. The conventional cutting method has a slow cutting process and a large heat-affected zone, which greatly affects the performance of the magnetic steel after cutting, and thus cannot be applied to the processing and forming of the magnetic steel.

[0005] Therefore, how to provide a magnetic steel processing method and a magnetic steel processing device to solve the above-mentioned defects in the existing manufacturing method has become a technical problem to be solved. SUMMARY

[0006] The present application aims at the defects and deficiencies in the prior art, and provides a magnetic steel processing method and a magnetic steel processing device. The laser beam cutting combined with temperature field and magnetic field regulation is used to skillfully solve the defects in the prior art when cutting the magnetic steel.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0008] The present application provides a magnetic steel processing method, which comprises the following contents:

[0009] S1. The temperature control processing table has a temperature transfer area for cooling the magnetic steel. The magnetic steel is fixed to the temperature control processing table and is in contact with the temperature transfer area to cool the magnetic steel.

[0010] The temperature of the temperature transfer area is less than the Curie temperature of the magnetic steel and does not affect the toughness of the material.

[0011] S2. Placing the to-be-cut region of the magnetic steel into an applied magnetic field, and starting the laser cutting head to cut the magnetic steel, wherein the magnetic field strength of the applied magnetic field is greater than or equal to the coercivity of the magnetic steel.

[0012] Preferably, the temperature range of the temperature transfer region in S1 is -20℃ to 20℃.

[0013] Preferably, the applied magnetic field in S2 is generated by an excitation coil.

[0014] Preferably, the excitation coil has 500 turns, a current adjustment range of 0-50A, a working frequency of 50Hz-1000Hz, and a magnetic field strength range of 10mT-200mT.

[0015] Preferably, the laser used by the laser cutting head in S2 is any one of a solid-state laser, a semiconductor laser, and a fiber laser.

[0016] Preferably, the laser used by the laser cutting head in S2 has a power range of 100W-3000W and a cutting moving speed of 0.5m / min-2m / min.

[0017] The application also provides a magnetic steel processing device for the magnetic steel processing method, which comprises a temperature control system, a magnetic field control system, and a laser cutting head.

[0018] The magnetic field control system comprises a magnetic field generating device capable of generating an applied magnetic field and a second controller signal-connected with the magnetic field generating device, the magnetic field generating device is disposed on one side of the temperature control processing platform, and the magnetic field generated by the magnetic field generating device covers at least the to-be-cut region of the magnetic steel.

[0019] The laser cutting head is disposed on the upper part of the to-be-cut region and can penetrate the entire to-be-cut region along the cutting direction.

[0020] Preferably, the temperature control system further comprises a temperature measuring component, the temperature measuring component comprises a first temperature measuring component and a second temperature measuring component, the first temperature measuring component is located on the lower part of the to-be-cut region, the second temperature measuring component is located on the side of the temperature transfer region, and the first temperature measuring component, the second temperature measuring component, and the temperature control processing platform are signal-connected with the first controller, respectively.

[0021] Preferably, the temperature control processing platform is internally provided with a cooling conduit connected with a cold source, and the cooling conduit is coiled to form a ring structure.

[0022] Preferably, the magnetic field generating device is an excitation coil, which is placed at the bottom of the temperature-controlled processing table arranged horizontally; or the excitation coil is sleeved outside the temperature-controlled processing table arranged vertically.

[0023] The present application has the following beneficial effects over the prior art:

[0024] 1. The present application adopts the mode of laser beam cutting combined with temperature field and magnetic field regulation and control to solve the cutting defects of the magnetic steel according to the essential reasons for the defects. Specifically, the magnetic steel is attached to the temperature transfer zone, the magnetic steel is cooled through the temperature transfer zone, the heat dissipation capacity of the unprocessed area of the magnetic steel is strengthened, the heat is more efficiently conducted from the molten pool area to the unprocessed area, the accumulation of heat around the cutting area is reduced, the cooling speed of the molten pool area and the surrounding area is accelerated, and the size of the heat affected zone is effectively controlled; in addition, the cutting area of the magnetic steel is placed in an external magnetic field, the magnetic field strength of the processing environment is regulated and controlled through the external magnetic field, not only the grain orientation of the re-solidification in the molten pool can be regulated and controlled, the residual magnetism of the cut seam magnetic steel can be improved, but also the magnetic force in the heat affected zone and the magnetic steel can be constantly supplemented through the external magnetic field, so that the problem of excessive loss of magnetism during processing is avoided; that is, the magnetic steel processing method of the present application can solve the defects of magnetic decay and excessive heat affected zone in the traditional magnetic steel cutting process, and ensure the magnetic performance of the processed magnetic steel.

[0025] The other technical solutions of the present application have the following beneficial effects over the prior art:

[0026] 2. The temperature of the processing environment is controlled by the temperature regulation system, and the temperature of the workpiece to be processed is maintained at-20℃ to 20℃, so that the unprocessed base material serves as a heat conduction zone to conduct the molten pool temperature, accelerate the solidification speed of the molten pool, reduce the range of the heat affected zone, increase the temperature gradient, make the re-solidified cut seam structure obtain smaller grain size, improve the size of the coercive force in the cut seam, and avoid the problem of rapid decline of the magnetic property of the heat affected zone magnetic steel caused by excessive heat affected zone and long cooling time, so as to improve the cutting quality. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 It is a structure schematic view of the temperature-controlled processing table disclosed in the specific embodiment of the present application when it is placed horizontally;

[0029] Figure 2 This is a schematic diagram of the structure of a temperature-controlled processing table when it is placed vertically, according to a specific embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of a temperature-controlled processing table disclosed in a specific embodiment of the present invention.

[0031] Among them, 1. Magnet; 2. Temperature-controlled processing table; 3. Excitation coil; 4. Controller; 5. Laser cutting head; 6. External magnetic field; 7. Laser beam; 8. Cold source; 9. Second temperature measuring component; 10. Cooling conduit; 11. First temperature measuring component. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figures 1 to 3 As shown, the present invention provides a method for processing magnetic steel, including the following:

[0035] S1. The temperature-controlled processing table 2 has a temperature transfer zone for cooling the magnet 1. The magnet 1 is fixed to the temperature-controlled processing table 2 and is in contact with the temperature transfer zone to cool the magnet 1.

[0036] The temperature of the temperature transfer zone is lower than the Curie temperature of the magnet 1 and will not affect the toughness of the material. The magnet 1 is cooled to a moderately low temperature through the temperature transfer zone. The temperature range is preferably such that heat input can be reduced without excessively affecting the brittleness of the material. In one embodiment, the temperature range of the temperature transfer zone is -20°C to 20°C.

[0037] S2. Put the to-be-cut region of the magnetic steel 1 into the external magnetic field 6, and start the laser cutting head 5 to cut the magnetic steel 1, wherein the magnetic field strength of the external magnetic field 6 is greater than or equal to the coercive force of the magnetic steel 1. That is, the magnetic field strength of the external magnetic field 6 is generally comparable to or slightly higher than the coercive force of the magnetic steel 1, so as to ensure that the direction of the magnetic domain can be rearranged and maintained in a high-temperature environment, and the magnetism of the magnetic steel is maintained. In addition, the external magnetic field 6 can also guide the flow direction of the molten pool, and regulate the cutting quality. Specifically, the magnetic field is perpendicular to the surface of the workpiece, can generate more effective force on the current (such as induced current) in the molten pool, control the stability of the metal melt in the vertical direction, and prevent excessive spatter or irregular flow. In addition, the influence of the vertical magnetic field on the surface tension is relatively uniform, which is helpful to realize better molten pool shape control. In the case of allowing, the magnetic field strength of the external magnetic field 6 should be as large as possible to resist the thermal demagnetization phenomenon and help maintain the magnetism of the magnetic steel 1. In an embodiment, the external magnetic field 6 is generated by the excitation coil 3, the number of turns of the excitation coil 3 is 500 turns, the current adjustment range is 0-50A, the working frequency is 50Hz-1000Hz, and the generated magnetic field strength range is 10mT-200mT. The thickness of the magnetic steel 1 is 0.5mm-5mm, and the material of the magnetic steel 1 is a neodymium iron boron magnetic steel or an aluminum-nickel-cobalt magnetic steel.

[0038] S3. When the cutting end point is reached, first turn off the laser cutting head; after the cutting seam is solidified, the temperature control processing table stops working, and finally the external magnetic field stops working, the power is turned off, and the cutting is completed.

[0039] The laser used by the laser cutting head 5 is any one of a solid-state laser, a semiconductor laser and a fiber laser, and it is appropriate to use a laser beam 7 capable of generating a small spot and high energy density. In an embodiment, the laser used by the laser cutting head 5 is a single-mode 2000W fiber laser with a 14-micron fiber, the energy density is >10 8 W / cm 2 , the power range of the laser is 100W-3000W, the cutting moving speed of the laser cutting head 5 is 0.5m / min-2m / min, and in the case of allowing, the cutting speed of the laser cutting head 5 should be as fast as possible to shorten the cutting time and reduce the temperature rise of the to-be-cut region of the magnetic steel 1.

[0040] The application also provides a magnetic steel processing device, which comprises a temperature control system, a magnetic field control system and a laser cutting head 5. The temperature control system comprises a fixed temperature control processing table 2 and a first controller connected with the temperature control processing table 2. The temperature control processing table 2 has a temperature transfer area for cooling the magnetic steel 1, and the magnetic steel 1 is placed on the temperature control processing table 2 and is in contact with the temperature transfer area.

[0041] The magnetic field regulation system comprises a magnetic field generating device capable of generating an applied magnetic field 6 and a second controller in signal connection with the magnetic field generating device. The magnetic field generating device is placed on one side of the temperature-controlled processing platform 2, and the magnetic field generated by the magnetic field generating device covers at least the cutting area of the magnetic steel 1. The laser cutting head 5 is placed on the upper part of the cutting area and can penetrate the entire cutting area along the cutting direction. In an embodiment, the magnetic field generating device is an excitation coil 3, and other devices capable of generating a magnetic field, such as a permanent magnet, also belong to the protection scope of the present application.

[0042] The temperature-controlled processing platform 2 is a platform structure, and the two ends of the platform structure are fixedly arranged on a fixed object, or the temperature-controlled processing platform 2 is a platform structure with legs, which is placed on the top surface of the ground or other fixed objects through the legs. When the cutting form is a flat plate (for example, the workpiece is placed horizontally Figure 1 , the temperature-controlled processing platform 2 is placed horizontally, and the top surface of the temperature-controlled processing platform 2 is the temperature transfer area; when the cutting form is a vertical plate (for example, the workpiece is placed vertically Figure 2 , the temperature-controlled processing platform 2 is placed vertically, and the temperature-controlled processing platform 2 comprises a left half part and a right half part arranged vertically. At this time, the side close to each other of the left half part and the right half part is the temperature transfer area (i.e., the right side of the left half part and the left side of the right half part are the temperature transfer area).

[0043] In order to better control the temperature during cutting, the temperature regulation system further comprises a temperature measuring component in signal connection with the first controller. The temperature measuring component comprises a first temperature measuring component 11 and a second temperature measuring component 9. The first temperature measuring component 11 is located at the lower part of the cutting area, and a non-contact temperature sensor is used for temperature measurement. The second temperature measuring component 9 is located at the side of the temperature transfer area. The first controller is also in signal connection with the laser cutting head 5. The temperature of the temperature-controlled processing platform 2 and / or the laser power and cutting speed of the laser cutting head 5 are regulated by the first controller, so that the ambient temperature and the temperature of the temperature transfer area can be maintained in a suitable low-temperature state. In an embodiment, the first temperature measuring component 11 and the second temperature measuring component 9 are both temperature sensors.

[0044] Whether it is magnetic field regulation or temperature control, it is managed by closed-loop feedback. For example, the first temperature measuring component 11 and the second temperature measuring component 9 provide real-time temperature data, which is fed back to the first controller. The first controller adjusts the output of the cooling system according to the set target value. Similarly, a magnetic field sensor is arranged around the applied magnetic field 6 to provide real-time magnetic field data, and the second controller adjusts the excitation current as needed. In an embodiment, the first controller and the second controller are the same controller, i.e. Figure 1 and Figure 2The controller 4 in the system can simultaneously accept data inputs from multiple sensors including temperature sensors, magnetic field sensors, laser power monitors, etc., and then adjust the temperature of the temperature-controlled processing platform 2, the flow rate of the auxiliary gas (by adjusting the flow rate of the auxiliary gas, the purpose of adjusting the laser power is achieved), the current of the excitation coil 3, etc. according to the requirements of the processing process, to realize the linkage control of multiple variables.

[0045] The temperature-controlled processing platform 2 is internally provided with a cooling conduit 10 connected to a cold source 8. The cooling conduit 10 is coiled to form a ring structure. The cold source 8 can be a refrigerant such as liquid nitrogen, low-temperature water, dry ice, etc. In an embodiment, the cold source 8 is a liquid nitrogen tank.

[0046] When the cutting form is a flat plate, the excitation coil 3 is placed at the bottom of the temperature-controlled processing platform 2. The benefits of such arrangement are discussed from the following aspects.

[0047] 1) Uniform coverage of magnetic field: The excitation coil 3 is placed below the magnetic steel 1, which can form a relatively uniform vertical magnetic field on the entire surface of the magnetic steel 1. This vertical magnetic field direction is very beneficial to control the vertical flow of the molten pool and the convection behavior during the metal solidification process, ensuring the stable flow and solidification of the molten pool metal during the laser cutting process.

[0048] 2) Reduce interference to laser path: If the excitation coil 3 is placed on the side of the magnetic steel 1, the position and size of the coil may affect the passage of the laser beam, especially in the case of flexible movement of the laser cutting head 5 during cutting. The excitation coil 3 placed below can keep the laser path undisturbed, thereby improving the flexibility and precision of the processing.

[0049] 3) Guide the flow direction of the molten pool: The magnetic field is perpendicular to the workpiece surface, which can generate more effective force on the current (such as induced current) in the molten pool, control the stability of the metal melt in the vertical direction, and prevent excessive spatter or irregular flow. In addition, the vertical magnetic field has a more uniform effect on surface tension, which helps to achieve better molten pool shape control.

[0050] 4) Optimization of heat management: The excitation coil 3 placed below does not conflict with other auxiliary equipment such as the laser cutting head 5 and the temperature-controlled processing platform 2. This arrangement is easier to use with the temperature-controlled processing platform 2 to more effectively remove heat during welding or cutting, reducing the heat-affected zone.

[0051] When the cutting form is a vertical plate, the excitation coil 3 is placed outside the overall structure composed of the left half and the right half. The benefits of such arrangement are discussed from the following aspects.

[0052] 1) Coverage effect of magnetic field: When the workpiece is placed vertically, the excitation coil 3 is arranged on the left and right sides, which can form a transverse magnetic field in the cutting area, so that the magnetic field can better cover the width of the entire cutting seam. If the coil is set on the bottom surface, the action of the magnetic field may be concentrated on the bottom of the workpiece, so that the magnetic field cannot uniformly act on the cutting area, which will affect the cutting quality.

[0053] 2) Stability and control effect: The arrangement of the magnetic field on the left and right sides can effectively control the flow of the molten pool, especially in the vertical direction. The gravity will cause the molten pool to sag, and the transverse magnetic field can offset part of the gravity effect, keeping the uniformity of the molten pool. The excitation coil 3 arranged on the bottom cannot provide effective magnetic field coverage in the direction of the gravity of the molten pool.

[0054] It should be noted that for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A method of processing a magnetic steel, characterized by: The application is applied to a magnetic steel processing device, which comprises a temperature control system, a magnetic field control system and a laser cutting head, the temperature control system comprises a temperature control processing table fixedly arranged and a first controller in signal connection with the temperature control processing table, the temperature control processing table has a temperature transmission area for cooling the magnetic steel, the magnetic steel is arranged on the temperature control processing table and is in contact with the temperature transmission area; The magnetic field control system comprises a magnetic field generating device capable of generating an external magnetic field and a second controller in signal connection with the magnetic field generating device, the magnetic field generating device is arranged on one side of the temperature control processing table, and the magnetic field generated by the magnetic field generating device covers at least the cutting area of the magnetic steel; The laser cutting head is arranged on the upper part of the cutting area and can penetrate through the whole cutting area along the cutting direction; The temperature control system further comprises temperature measuring components, the temperature measuring components comprise a first temperature measuring component and a second temperature measuring component, the first temperature measuring component is arranged on the lower part of the cutting area, the second temperature measuring component is arranged on the side of the temperature transmission area, and the first temperature measuring component, the second temperature measuring component and the temperature control processing table are in signal connection with the first controller; A magnetic field sensor is arranged around the external magnetic field to provide real-time magnetic field data, the second controller adjusts the excitation current as required, the controller simultaneously receives the data input of the temperature sensor, the magnetic field sensor and the laser power monitor, then adjusts the temperature of the temperature control processing table, the flow rate of the auxiliary gas and the current of the excitation coil according to the requirements of the processing process, so as to realize the linkage control of multiple variables; The magnetic steel processing method comprises the following contents: S1. The temperature control processing table has a temperature transmission area for cooling the magnetic steel, the magnetic steel is fixed on the temperature control processing table and is in contact with the temperature transmission area, so as to cool the magnetic steel; The temperature of the temperature transmission area is less than the Curie temperature of the magnetic steel and does not affect the toughness of the material; S2. The cutting area of the magnetic steel is arranged in the external magnetic field, and the laser cutting head is started to cut the magnetic steel, wherein the magnetic field strength of the external magnetic field is greater than or equal to the coercive force of the magnetic steel; S3. When the cutting end point is reached, the laser cutting head is turned off; after the cutting seam is solidified, the temperature control processing table and the external magnetic field stop working, the power is turned off, and the cutting is completed; The temperature range of the temperature transmission area in S1 is-20℃ to 20℃; The number of turns of the excitation coil is 500, the current adjustment range is 0 to 50A, the working frequency is 50Hz to 1000Hz, and the magnetic field strength range is 10mT to 200mT; The power range of the laser used by the laser cutting head in S2 is 100W to 3000W, and the cutting moving speed is 0.5m / min to 2m / min.

2. The magnetic steel machining method of claim 1, wherein: The external magnetic field in S2 is generated by the excitation coil.

3. The magnetic steel machining method of claim 1, wherein: The laser used by the laser cutting head in S2 is any one of a solid-state laser, a semiconductor laser and a fiber laser.

4. The magnetic steel machining method of claim 1, wherein: The inside of the temperature control processing table is provided with a cooling conduit connected with a cold source, and the cooling conduit is arranged in a coil shape.

5. The method of claim 1 or 4, wherein: The magnetic field generating device is an excitation coil, and the excitation coil is arranged at the bottom of the horizontally arranged temperature control processing table; or the excitation coil is sleeved outside the vertically arranged temperature control processing table.

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