Magnetic steel processing method and magnetic steel processing device

Abstract

The invention discloses a magnetic steel processing method and a magnetic steel processing device, and belongs to the technical field of laser processing, and the magnetic steel processing method comprises the following steps: S1, a temperature control processing table is provided with a temperature transfer area for cooling, and magnetic steel is fixed on the temperature control processing table and is attached to the temperature transfer area so as to cool the magnetic steel; wherein the temperature of the temperature transfer area is lower than the Curie temperature of the magnetic steel and does not affect the toughness of the material; s2, the to-be-cut area of the magnetic steel is placed in an external magnetic field, a laser cutting head is started to cut the magnetic steel, and the magnetic field intensity of the external magnetic field is larger than or equal to the coercive force of the magnetic steel; s3, when the cutting end point is reached, the laser cutting head is closed; after the kerf is solidified, the temperature control machining table and the external magnetic field stop working, the power supply is turned off, and cutting is completed; magnetic force in the magnetic steel can be supplemented through an external magnetic field, and the problem of excessive magnetic loss in the machining process is avoided; by cooling the magnetic steel, the size of a heat affected zone can be reduced, the influence on the magnetism of the magnetic steel is reduced, and the machining method and the machining device can be suitable for the magnetic steel.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a magnetic steel processing method and a magnetic steel processing device. Background Art

[0002] The current mainstream magnets include AlNiCo magnets, ferrite magnets, NdFeB magnets, etc. They have different metal composition, different magnetic properties, and thus different uses. They are mainly used in various sensors, instruments, electronics, electromechanics, medical treatment, teaching, automobiles, aviation, military technology and other fields.

[0003] At present, the main production processes of magnetic steel include sintering, bonding and casting. However, these methods only involve manufacturing multiple pieces of materials with similar functions through molds, and subsequent post-processing is required through surface processing or electroplating. For special small-scale applications, there are currently only processing methods such as wire cutting or grinding. Due to the extremely high hardness of magnetic steel, wire cutting can only process thin plates; and grinding is time-consuming and has low production efficiency.

[0004] Due to the special nature of magnetic steel, its Curie temperature is generally between 400℃ and 800℃. When the temperature of magnetic steel exceeds the Curie temperature, the molecular thermal motion inside the magnetic steel causes irreversible disorder of magnetic dipole moment arrangement, causing the magnetism of the magnetic steel to drop rapidly, and this process is irreversible. Conventional cutting methods have a slow cutting process and a large heat-affected zone, which will greatly affect the performance of the magnetic steel after cutting, and therefore cannot be used in the processing and forming of magnetic steel.

[0005] Therefore, how to provide a magnetic steel processing method and a magnetic steel processing device to solve the above-mentioned defects existing in the existing manufacturing methods has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] The purpose of the present invention is to provide a magnetic steel processing method and a magnetic steel processing device in view of the defects and shortcomings in the prior art, which adopts laser beam cutting combined with temperature field and magnetic field control to cleverly solve the defects of the prior art in cutting magnetic steel.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] The present invention provides a magnetic steel processing method, comprising the following contents:

[0009] S1. The temperature-controlled processing table has a temperature transfer zone for cooling the magnetic steel. The magnetic steel is fixed to the temperature-controlled processing table and fits with the temperature transfer zone to cool the magnetic steel;

[0010] Among them, the temperature of the temperature transfer zone is lower than the Curie temperature of the magnetic steel and will not affect the toughness of the material;

[0011] S2. Place the area of ​​the magnetic steel to be cut in an external magnetic field, and start the laser cutting head to cut the magnetic steel, wherein the magnetic field strength of the external magnetic field is ≥ the coercive force of the magnetic steel.

[0012] Preferably, the temperature range of the temperature transfer zone in S1 is -20°C to 20°C.

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

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

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

[0016] Preferably, the power range of the laser used by the laser cutting head in S2 is 100W to 3000W, and the cutting movement speed is 0.5m / min to 2m / min.

[0017] The present invention also provides a magnetic steel processing device, which is used in the magnetic steel processing method, and includes a temperature control system, a magnetic field control system and a laser cutting head. The temperature control system includes a fixedly arranged temperature control processing table and a first controller connected to the temperature control processing table by signal. The temperature control processing table has a temperature transfer area for cooling the magnetic steel. The magnetic steel is placed on the temperature control processing table and fits the temperature transfer area.

[0018] The magnetic field control system includes a magnetic field generating device capable of generating an external magnetic field and a second controller connected to the magnetic field generating device by signal, wherein the magnetic field generating device is placed on one side of the temperature-controlled processing table, and the magnetic field generated by the magnetic field generating device at least covers the area to be cut of the magnetic steel;

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

[0020] Preferably, the temperature control system also includes a temperature measuring component, which includes a first temperature measuring component and a second temperature measuring component, the first temperature measuring component is located at the lower part of the area to be cut, and the second temperature measuring component is located at the side of the temperature transfer zone, and the first temperature measuring component, the second temperature measuring component and the temperature control processing table are respectively connected to the first controller signal.

[0021] Preferably, a cooling conduit connected to a cold source is provided inside the temperature-controlled processing table, and the cooling conduit is coiled to form a ring-shaped structure.

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

[0023] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0024] 1. The present invention aims at the essential cause of defects in magnetic steel cutting, and adopts laser beam cutting combined with temperature field and magnetic field control to cleverly solve its cutting defects. Specifically, by setting the magnetic steel to fit with the temperature transfer zone, the magnetic steel is cooled by the temperature transfer zone, the heat dissipation capacity of the unprocessed area in the magnetic steel is enhanced, and the heat is more efficiently transferred from the molten pool area to the unprocessed area, reducing the accumulation of heat around the cutting area, accelerating the cooling rate of the molten pool area and its surrounding areas, and effectively controlling the size of the heat-affected zone; in addition, the area to be cut of the magnetic steel is placed in an external magnetic field, and the magnetic field strength of the processing environment is controlled by the external magnetic field, which can not only control the orientation of the re-solidified grains in the molten pool and improve the residual magnetism of the slit magnetic steel magnet, but also use the external magnetic field to continuously supplement the magnetic force in the heat-affected zone and the magnetic steel, avoiding the problem of excessive magnetic loss during the processing process; that is, the magnetic steel processing method of the present invention can solve the defects of magnetic fading and excessive heat-affected zone encountered in the traditional magnetic steel cutting process, and ensure the magnetic performance of the magnetic steel after processing.

[0025] Other technical solutions of the present invention have achieved the following beneficial effects compared with the prior art:

[0026] 2. The present invention controls the processing environment temperature through a temperature control system, and maintains the temperature of the workpiece to be processed between -20°C and 20°C, so that the unprocessed base material acts 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 its temperature gradient, and make the re-solidified cut seam structure obtain a smaller grain size, increase the size of the coercive force in the cut seam, and avoid the problem of rapid decrease in magnetic properties of the magnetic steel in the heat-affected zone due to excessive heat-affected zone and excessive cooling time, thereby improving the cutting quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 It is a structural schematic diagram of a temperature-controlled processing table when it is placed horizontally according to a specific embodiment of the present invention;

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

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

[0031] Among them, 1. magnetic steel; 2. temperature control processing table; 3. excitation coil; 4. controller; 5. laser cutting head; 6. external magnetic field; 7. laser beam; 8. cold source; 9. second temperature measurement component; 10. cooling duct; 11. first temperature measurement component. DETAILED DESCRIPTION

[0032] 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.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is 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 magnetic steel processing method, comprising the following contents:

[0035] S1. The temperature-controlled processing table 2 has a temperature transfer zone for cooling the magnetic steel 1. The magnetic steel 1 is fixed to the temperature-controlled processing table 2 and fits with the temperature transfer zone to cool the magnetic steel 1;

[0036] The temperature of the temperature transfer zone is lower than the Curie temperature of the magnetic steel 1 and will not affect the toughness of the material. The magnetic steel 1 is cooled to a moderately low temperature through the temperature transfer zone, wherein the temperature range is suitable for reducing heat input and not 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. Place the area to be cut of the magnetic steel 1 in 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 ≥ the coercive force of the magnetic steel 1. That is, the magnetic field strength of the external magnetic field 6 should usually be equivalent to or slightly higher than the coercive force of the magnetic steel 1 to ensure that the direction of the magnetic domain can be rearranged and maintained in a high-temperature environment, and the magnetic properties of the magnetic steel can be maintained; in addition, the external magnetic field 6 can also guide the flow direction of the molten pool and regulate the cutting quality. The specific magnetic field is perpendicular to the surface of the workpiece, which can produce 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 splashing or irregular flow. In addition, the vertical magnetic field has a more uniform effect on the surface tension, which helps to achieve better control of the molten pool morphology. Where permitted, the magnetic field strength of the external magnetic field 6 should be as large as possible to resist thermal demagnetization and help maintain the magnetism of the magnetic steel 1. In one embodiment, the external magnetic field 6 is generated by the excitation coil 3, the number of turns of the excitation coil 3 is 500, the current adjustment range is 0-50A, the operating 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 neodymium iron boron magnet or aluminum nickel cobalt magnet.

[0038] S3. When the cutting end point is reached, the laser cutting head is turned off first; after the cut seam solidifies, the temperature-controlled 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 in the laser cutting head 5 is any one of a solid laser, a semiconductor laser, and a fiber laser, and is preferably a laser beam 7 that can produce a small spot and high energy density. In one embodiment, the laser used in the laser cutting head 5 is a single-mode 2000W fiber laser with a 14-micron fiber and an energy density of >10 8 W / cm 2 The power range of the laser is 100W to 3000W, the cutting moving speed of the laser cutting head 5 is 0.5m / min to 2m / min, and when permitted, 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 area to be cut of the magnetic steel 1.

[0040] The present invention also provides a magnetic steel processing device, including a temperature control system, a magnetic field control system and a laser cutting head 5, wherein the temperature control system includes a fixedly arranged temperature control processing table 2 and a first controller connected to the temperature control processing table 2 by signal, 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 fits the temperature transfer area;

[0041] The magnetic field control system includes a magnetic field generating device capable of generating an external magnetic field 6 and a second controller connected to the magnetic field generating device by signal. The magnetic field generating device is placed on one side of the temperature-controlled processing table 2, and the magnetic field generated by the magnetic field generating device at least covers the area to be cut of the magnetic steel 1; the laser cutting head 5 is placed on the upper part of the area to be cut and can penetrate the entire area to be cut along the cutting direction. In one 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 fall within the scope of protection of the present invention.

[0042] The temperature control processing table 2 is a platform-like structure, and both ends of the platform-like structure are fixedly arranged on a fixed object, or the temperature control processing table 2 is a platform-like structure with legs, and is placed on the ground or the top surface of other fixed objects through the legs. Figure 1 , the workpiece is placed horizontally), the temperature control processing table 2 is placed horizontally, and the top surface of the temperature control processing table 2 is the temperature transfer area; when the cutting form is a vertical plate shape (such as Figure 2 , at this time the workpiece is placed vertically), the temperature controlled processing table 2 is placed vertically, and the temperature controlled processing table 2 includes a vertically arranged left half and a right half. At this time, the side of the left half and the right half that are close to each other is the temperature transfer zone (that is, the right side of the left half and the left side of the right half are the temperature transfer zone).

[0043] In order to better control the temperature during cutting, the temperature control system also includes a temperature measuring component connected to the first controller signal, and the temperature measuring component includes a first temperature measuring component 11 and a second temperature measuring component 9, wherein the first temperature measuring component 11 is located at the lower part of the area to be cut, and a non-contact temperature sensor is used to measure the temperature, and the second temperature measuring component 9 is located at the side of the temperature transfer zone, and the first controller is also connected to the laser cutting head 5 signal. The temperature of the temperature control processing table 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 zone can be maintained at a suitable low temperature state. In one embodiment, the first temperature measuring component 11 and the second temperature measuring component 9 are both temperature sensors.

[0044] Both magnetic field regulation and temperature control are managed through closed-loop feedback. For example, the first temperature measurement component 11 and the second temperature measurement component 9 provide real-time temperature data and feed it back to the first controller, which adjusts the output of the cooling system according to the set target value. Similarly, a magnetic field sensor is set around the external magnetic field 6 to provide real-time magnetic field data, and the second controller adjusts the excitation current as needed. In one embodiment, the first controller and the second controller are set to be the same controller, that is, Figure 1 and Figure 2The controller 4 in the system is configured to simultaneously receive data inputs from multiple sensors including temperature sensors, magnetic field sensors, laser power monitoring, etc., and then adjust the temperature of the temperature-controlled processing table 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) and the current of the excitation coil 3 according to the requirements of the processing technology, so as to realize the linkage control of multiple variables.

[0045] A cooling duct 10 connected to a cold source 8 is provided inside the temperature-controlled processing table 2. The cooling duct 10 is coiled to form a ring structure. The cold source 8 can be a refrigerant such as liquid nitrogen, cryogenic water, dry ice, etc. In one embodiment, the cold source 8 is a liquid nitrogen box.

[0046] When the cutting form is a flat plate, the excitation coil 3 is placed at the bottom of the temperature-controlled processing table 2; the advantages of this arrangement are discussed from the following aspects.

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

[0048] 2) Reduce interference with the 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 path of the laser beam, especially when the laser cutting head 5 needs to be flexibly moved during cutting. The excitation coil 3 arranged below can keep the laser path undisturbed, thereby improving the flexibility and accuracy of processing.

[0049] 3) Guiding the flow direction of the molten pool: The magnetic field is perpendicular to the workpiece surface, which can produce 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 splashing or irregular flow. In addition, the vertical magnetic field has a more uniform effect on the surface tension, which helps to achieve better control of the molten pool morphology.

[0050] 4) Optimization of thermal management: The excitation coil 3 arranged below will not conflict with other auxiliary equipment such as the laser cutting head 5 and the temperature control processing table 2. This arrangement is easier to use in combination with the temperature control processing table 2 to more effectively remove heat during welding or cutting and reduce the heat affected zone.

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

[0052] 1) Covering 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 horizontal 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 effect of the magnetic field may be concentrated on the bottom of the workpiece, so that the magnetic field cannot act evenly on the cutting area, which will affect the cutting quality.

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

[0054] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A magnetic steel processing method, characterized in that: Includes the following: S1. The temperature-controlled processing table has a temperature transfer zone for cooling the magnetic steel. The magnetic steel is fixed to the temperature-controlled processing table and fits with the temperature transfer zone to cool the magnetic steel; Among them, the temperature of the temperature transfer zone is lower than the Curie temperature of the magnetic steel and will not affect the toughness of the material; S2. placing the area of ​​the magnetic steel to be cut in an external magnetic field, and starting the laser cutting head to cut the magnetic steel, wherein the magnetic field strength of the external magnetic field is ≥ the coercive force of the magnetic steel; S3. When the cutting end point is reached, the laser cutting head is turned off; when the cut seam solidifies, the temperature-controlled processing table and the external magnetic field stop working, the power is turned off, and the cutting is completed.

2. The magnetic steel processing method according to claim 1, characterized in that: The temperature range of the temperature transfer zone in S1 is -20°C to 20°C.

3. The magnetic steel processing method according to claim 2, characterized in that: The external magnetic field in S2 is generated by an excitation coil.

4. The magnetic steel processing method according to claim 3, characterized in that: The number of turns of the excitation coil is 500, the current adjustment range is 0-50A, the operating frequency is 50Hz-1000Hz, and the magnetic field strength range is 10mT-200mT.

5. The magnetic steel processing method according to claim 1, characterized in that: The laser used in the laser cutting head in S2 is any one of a solid laser, a semiconductor laser, and a fiber laser.

6. The magnetic steel processing method according to claim 5, characterized in that: The power range of the laser used in the laser cutting head of S2 is 100W to 3000W, and the cutting moving speed is 0.5m / min to 2m / min.

7. A magnetic steel processing device, used in the magnetic steel processing method according to any one of claims 1 to 6, characterized in that: It includes a temperature control system, a magnetic field control system and a laser cutting head. The temperature control system includes a fixed temperature control processing table and a first controller connected to the temperature control processing table by signal. The temperature control processing table has a temperature transfer area for cooling the magnetic steel. The magnetic steel is placed on the temperature control processing table and fits the temperature transfer area. The magnetic field control system includes a magnetic field generating device capable of generating an external magnetic field and a second controller connected to the magnetic field generating device by signal, wherein the magnetic field generating device is placed on one side of the temperature-controlled processing table, and the magnetic field generated by the magnetic field generating device at least covers the area to be cut of the magnetic steel; The laser cutting head is placed on the upper part of the area to be cut and can penetrate the entire area to be cut along the cutting direction.

8. The magnetic steel processing device according to claim 7, characterized in that: The temperature control system also includes a temperature measuring component, which includes a first temperature measuring component and a second temperature measuring component. The first temperature measuring component is located at the lower part of the area to be cut, and the second temperature measuring component is located at the side of the temperature transfer zone. The first temperature measuring component, the second temperature measuring component and the temperature control processing table are respectively connected to the first controller signal.

9. The magnetic steel processing device according to claim 8, characterized in that: A cooling conduit connected to a cold source is arranged inside the temperature-controlled processing table, and the cooling conduit is coiled to form a ring-shaped structure.

10. The magnetic steel processing device according to claim 8 or 9, characterized in that: The magnetic field generating device is an excitation coil, and the excitation coil is placed at the bottom of a horizontally arranged temperature-controlled processing table; or the excitation coil is sleeved on the outside of a vertically arranged temperature-controlled processing table.

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