An electromagnetic field-assisted thick plate laser cutting device

Abstract

An electromagnetic field-assisted thick plate laser cutting device, comprising a laser head slidably arranged on the gantry of a gantry cutting machine. A loading table is provided below the laser head, and a workpiece is placed on the loading table. Electric field generating devices are symmetrically arranged at both ends of the workpiece. The electric field generating device includes a pressure sensor, a pneumatic device, an electrode, a spring, and a conductive core arranged in sequence along the transverse direction. Magnetic field generating devices are provided on both sides of the laser head. The magnetic field generating device includes two planetary gear mechanisms. A large coil and four small coils are arranged between the two planetary gear mechanisms. The large coil is fixed on a large magnetic core shaft, and the small coils are fixed on small magnetic core shafts. Both ends of the large magnetic core shaft are fixedly connected to the sun gears of the corresponding planetary gear mechanisms, and both ends of the small magnetic core shafts are fixedly connected to the planetary gears of the corresponding planetary gear mechanisms. The present invention adopts the reverse rotation of the large and small coils to control the strength change of the magnetic field at the plate, generate Lorentz forces of different magnitudes, and realize a sine co-directional magnetic field.

Description

Technical Field

[0001] The present invention relates to an electromagnetic field assisted thick plate laser cutting device. Background Art

[0002] Laser cutting technology has the advantages of high precision, high economic efficiency, strong controllability, etc., and is widely used in cutting workpieces. During the laser cutting process, the molten pool undergoes a process of rapid cooling and heating. At the same time, due to the increase in the thickness of the plate, defects such as cracks are extremely likely to form in the cutting area. In view of the above problems in laser processing, some scholars have proposed a method of externally applying an electromagnetic field to assist laser cutting. By applying the required electromagnetic field in the molten pool, a corresponding Lorentz force is formed in the molten pool to regulate the flow of the molten pool solution, reduce the cracking defects in the heat affected zone during the cutting process, and reduce slag hanging.

[0003] In the prior art, the electromagnetic field generating device is mainly generated by magnetic poles and capacitors, or by a magnetic coil. The generated magnetic field or electric field is basically in a stable state and cannot produce a sinusoidal electromagnetic field effect.

[0004] On July 29, 2019, the publication number was "CN110293324A", and the invention name was "An electromagnetic field assisted laser cutting method". This laser cutting method fixes the electromagnetic coil on the laser cutting head and moves randomly with the laser cutting head, which can better improve the cutting quality at the corner.

[0005] On January 10, 2020, the publication number was "CN209919102U", and the invention name was "An electromagnetic field assisted laser welding device". This method is based on this electromagnetic force and uses a laser system to control the air nozzle to weld thick plates, thus ensuring the forming quality of the weld.

[0006] On May 12, 2020, the publication number was "CN111136271A", and the invention name was "A disc type magnetic field generating device". This method uses adjustable magnetic poles to regulate the magnetic field range, direction, gradient, and magnitude according to the needs of laser processing parts, and then realizes the control of the convective behavior of the molten pool to improve the comprehensive mechanical properties of laser processing parts.

[0007] The magnetic field ranges generated by the disclosed single magnetic field or electromagnetic field assisted laser manufacturing devices are all fixed and non-adjustable, and different sizes of parts cannot be processed and manufactured with the same set of devices. It can only be applied to small workbenches, and the application of gantry laser cutters is not considered. Moreover, the generated magnetic field or electric field is a stable electromagnetic field and cannot change automatically with time. Summary of the Invention

[0008] To overcome the above problems, the present invention provides an electromagnetic field assisted thick plate laser cutting device.

[0009] The technical solution adopted by the present invention is as follows: An electromagnetic field-assisted thick plate laser cutting device includes a laser head slidably arranged on the gantry of a gantry cutting machine. It is set that the sliding direction of the laser head along the gantry is the transverse direction, and the horizontal direction perpendicular to the transverse direction is the longitudinal direction;

[0010] A workbench is arranged below the laser head, and a workpiece is placed on the workbench; Electric field generating devices are symmetrically arranged at both ends of the workpiece along the transverse direction, and the two electric field generating devices clamp and fix the workpiece; The electric field generating device includes a pressure sensor, a pneumatic device, an electrode, a spring, and a conductive core arranged in sequence along the transverse direction. The conductive core is made of a conductive material, and the spring is made of an insulating material; The pneumatic device is a cylinder, the base of the cylinder is connected to the pressure sensor, and the end of the output shaft of the cylinder is connected to a clamping disc; A through hole coaxial with the cylinder is arranged in the clamping disc. A spring and an electrode are connected at the end of the output shaft of the cylinder and located within the through hole. The electrode is sleeved within the spring, and the other end of the spring is connected to the conductive core; A distance is left between the electrode and the conductive core, and the electrode can contact the conductive core after the spring is compressed, thereby controlling the generation of an electric field; A sleeve is sleeved outside the conductive core, and the sleeve is made of an insulating material; A limiting step is arranged in the clamping disc, and a plurality of wedge-shaped baffles cooperating with the limiting step are arranged circumferentially on the sleeve. The wedge-shaped baffles can pop out or be pressed into the sleeve, and the wedge-shaped baffles are used to prevent the sleeve from being pushed out of the clamping disc by the spring;

[0011] Longitudinal guide rails are symmetrically arranged on both sides of the laser head along the transverse direction, and a magnetic field generating device is slidably connected to the longitudinal guide rails; The magnetic field generating device includes a cylindrical shell arranged along the longitudinal direction. The shell is made of an insulating material, and a trapezoidal hanging slider cooperating with the longitudinal guide rails is arranged on the shell; Two planetary gear mechanisms are arranged along the longitudinal direction within the shell, and the two planetary gear mechanisms are arranged facing each other; The planetary gear mechanism includes a sun gear, a ring gear, a planetary carrier, and four planetary gears supported on the planetary carrier; A large coil and four small coils are arranged between the two planetary gear mechanisms. The large coil is fixed on a large magnetic core shaft, and the small coil is fixed on a small magnetic core shaft; The two ends of the large magnetic core shaft are fixedly connected to the sun gears of the corresponding planetary gear mechanisms, and the two ends of the small magnetic core shaft are fixedly connected to the planetary gears of the corresponding planetary gear mechanisms; The sun gear of one of the planetary gear mechanisms is connected to the output shaft of the motor; The large coil rotates with the sun gear, and the small coil rotates with the planetary gear. The large coil and the small coil rotate in opposite directions, thereby generating a sinusoidal alternating magnetic field;

[0012] The electric field generating device (3) and the magnetic field generating device (2) are respectively electrically connected to a power supply.

[0013] Further, the spring is of a frustum structure. The pitch of the part of the spring close to the pneumatic device is 10 mm, the number of turns is 20, and the diameter is 5 mm; The pitch of the part of the spring close to the conductive core is 8, the number of turns is 10, and the diameter is 5 mm.

[0014] Furthermore, the magnetic field range of the sinusoidal alternating magnetic field is 5T to 20T, and the sinusoidal magnetic field difference fluctuates within the range of 0.5T to 1T; the reduction ratio of the planetary gear mechanism is 1:2.

[0015] Furthermore, the applicable frequency range of the power supply is 0 to 100HZ, and the waveform is a sine wave, square wave or sawtooth wave.

[0016] Furthermore, a protective gas device is coaxially arranged inside the laser head, and the protective gas output by the protective gas device is nitrogen or air, and the air pressure range is 0.5MPa to 10Mpa.

[0017] Furthermore, the large coil and the small coil are wound with copper wire or copper pipe.

[0018] The beneficial effects of the present invention are:

[0019] (1) By adopting the reverse rotation of the large and small coils, the strength change of the magnetic field at the plate is controlled, different magnitudes of Lorentz forces are generated, and a sinusoidal co-directional magnetic field is realized.

[0020] (2) By adopting a pneumatic design, the sleeve stroke can be changed for plates of different sizes.

[0021] (3) The electric field generation and termination are controlled by the electrode follow-up elastic contact part composed of a spring and an electrode. Description of the Drawings

[0022] Figure 1 is the front view of the present invention;

[0023] Figure 2a is the front view of the electric field generation device in the present invention;

[0024] Figure 2b is the structural schematic diagram of the large coil in the present invention;

[0025] Figure 3a is the front view of the magnetic field generation device in the present invention;

[0026] Figure 3b is Figure 3a the partial enlarged view at A in

[0027] Figure 4a is the structural schematic diagram of the sleeve in the present invention.

[0028] Figure 4b is the assembly schematic diagram of the sleeve and the clamping disc in the present invention.

[0029] Figure 5 is the generation principle diagram of the cutting Lorentz force in the present invention;

[0030] Figure 6 is the axonometric drawing of the present invention. Detailed implementation manners

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] In the description of the present invention, it should be noted that, as terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention. In addition, terms such as "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, as terms such as "installation", "connection", "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0034] Referring to the accompanying drawings, an electromagnetic field-assisted thick plate laser cutting device includes a laser head 1 slidably arranged on the gantry of a gantry cutting machine. A protective gas device is coaxially arranged inside the laser head 1. The protective gas output by the protective gas device is nitrogen or air, and the air pressure range is 0.5 MPa to 10 Mpa. It is set that the sliding direction of the laser head 1 along the gantry is the transverse direction, and the horizontal direction perpendicular to the transverse direction is the longitudinal direction;

[0035] A workbench 5 is arranged below the laser head 1, and a workpiece 4 is placed on the workbench 5; electric field generating devices 3 are symmetrically arranged at both ends of the workpiece 4 along the transverse direction, and the two electric field generating devices 3 clamp and fix the workpiece 4; the workbench 5 and the electric field generating devices 3 are on the same horizontal line and are placed in the center of the gantry cutting machine.

[0036] The electric field generating device 3 includes a pressure sensor 302, a pneumatic device 301, an electrode 307, a spring 303, and a conductive core 305 arranged in sequence along the transverse direction. The conductive core 305 is made of a conductive material, and the spring 303 is made of an insulating material. The pneumatic device 301 is a cylinder. The base of the cylinder is connected to the pressure sensor 302. A threshold is set in the pressure sensor 302, and when the threshold is exceeded, the pneumatic device 301 stops moving. The end of the output shaft of the cylinder is connected to a clamping disc 308. A through hole coaxial with the cylinder is provided inside the clamping disc 308. The spring 303 and the electrode 307 are connected at the position of the end of the output shaft of the cylinder and inside the through hole. The electrode 307 is sleeved inside the spring 303, and the other end of the spring 303 is connected to the conductive core 305. A distance is left between the electrode 307 and the conductive core 305. The electrode 307 can contact the conductive core 305 after the spring 303 is compressed, thereby controlling the generation of the electric field. A sleeve 306 is sleeved outside the conductive core 305, and the sleeve 306 is made of an insulating material. Specifically, the spring 303 has a frustum shape. The pitch of the part of the spring 303 close to the pneumatic device 301 is 10 mm, the number of turns is 20, and the diameter is 5 mm. The pitch of the part of the spring 303 close to the conductive core 305 is 8, the number of turns is 10, and the diameter is 5 mm. An outer sleeve 306 is provided on the outer periphery of the conductive core 305, and the sleeve 306 is made of an insulating material;

[0037] A limiting step 309 is provided inside the clamping disc 308. A plurality of wedge-shaped baffles 304 cooperating with the limiting step 309 are provided on the sleeve along the circumferential direction. During the process that the workpiece presses the sleeve and the spring contacts the conductive core, the sleeve moves towards the pressure sensor 302 side, and the limiting step 309 squeezes the wedge-shaped baffle 304. The wedge-shaped baffle 304 is pressed into the inside of the sleeve. After passing through the limiting step 309, the wedge-shaped baffle 304 pops out and cooperates with the limiting step 309 for limiting, so as to prevent the sleeve 306 from being pushed out of the clamping disc 308 by the spring 303;

[0038] On both sides of the laser head 1 symmetrically along the transverse direction, longitudinal guide rails are provided. A magnetic field generating device 2 is slidably connected to the longitudinal guide rails. The distance between the magnetic field generating device 2 and the laser head 1 is 1000 mm. The magnetic field generating device 2 includes a cylindrical outer shell 201 arranged longitudinally. The outer shell 201 is made of insulating material and has good wear resistance. A trapezoidal suspension slider 207 matching the longitudinal guide rails is provided on the outer shell 201. Two planetary gear mechanisms are arranged longitudinally inside the outer shell 201, and the two planetary gear mechanisms are arranged opposite to each other. The planetary gear mechanism includes a sun gear 202, a ring gear 204, a planetary carrier, and four planetary gears 203 supported on the planetary carrier. A large coil 206 and four small coils 208 are arranged between the two planetary gear mechanisms. The large coil 206 is fixed on a large magnetic core shaft, and the small coil 208 is fixed on a small magnetic core shaft. The two ends of the large magnetic core shaft are fixedly connected to the sun gears 202 of the corresponding planetary gear mechanisms, and the two ends of the small magnetic core shaft are fixedly connected to the planetary gears 203 of the corresponding planetary gear mechanisms. The sun gear 202 of one of the planetary gear mechanisms is connected to the output shaft of the motor. The sun gear 202 and the planetary gears 203 are made of stainless steel and have good wear resistance.

[0039] The large coil 206 and the small coil 208 are wound with copper wires or copper tubes. The large coil 206 rotates with the sun gear 202, and the small coil 208 rotates with the planetary gear 203. The large coil 206 and the small coil 208 rotate in opposite directions, thereby generating a sinusoidal alternating magnetic field. According to different plate thicknesses, the magnetic field range can be adjusted from 5 T to 20 T, and the difference of the sinusoidal magnetic field fluctuates within the range of 0.5 T to 1 T. The reduction ratio of the planetary gear mechanism is 1:2.

[0040] The electric field generating device 3 and the magnetic field generating device 2 are respectively electrically connected to a power supply. The applicable frequency range of the power supply is 0 - 100 HZ, and the waveform is a sine wave, a square wave or a sawtooth wave.

[0041] The usage method of the present invention is as follows:

[0042] (1) Place the workpiece to be processed on the surface of the loading table.

[0043] (2) Turn on the power supply and start the magnetic field generating device.

[0044] (3) Turn on the starting device, automatically adjust the stroke according to the pressure sensor until the workpiece is clamped to generate an electric field.

[0045] (4) Select appropriate laser process parameters and turn on the laser to cut the workpiece.

[0046] (5) Turn off the laser and the power supply, and the workpiece cutting is completed.

[0047] Embodiment 1

[0048] Refer to the appendix Figure 1This example is a conventional plate cutting example (cutting flat plate). In this example, the workpiece thickness is selected to be 5mm. First, the workpiece 104 is placed on the stage 105, the power is turned on, direct current is passed, the current is adjusted to generate a magnetic field of 5T, the rotation angular velocity is adjusted to 5rad / min, a magnetic field is generated, the pneumatic device is turned on, and the stroke is automatically adjusted to 1800mm through the pressure sensor. Select appropriate laser process parameters, turn on the laser, and pass the coaxial auxiliary gas. Finally, turn off the laser and power, and the workpiece cutting is completed.

[0049] Example 2

[0050] See attached Figure 1 The device of this example is the same as that of Example 1. The difference between this example and Example 1 is that the thickness of the workpiece is 60 mm, the current is adjusted so that the magnetic field is 20 T, the angular velocity of the gear rotation is adjusted to 10 rad / min, and the stroke is automatically adjusted to 500 mm by the pressure sensor.

[0051] The present invention controls the magnetic field size by adjusting the current size and the structural design during rotation, adjusts the threshold of the sensor, adapts to the size of the cutting workpiece, and then realizes the electromagnetic field assisted laser cutting required for processing workpieces of different sizes, thereby achieving the purpose of improving the overall cutting quality, reducing cracks in the heat-affected zone, and reducing the amount of slag. The present invention has the characteristics of flexible adjustment, simple operation, and a wide range of workpieces to be processed.

[0052] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms described in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. An electromagnetic field assisted thick plate laser cutting device, characterized in that: It includes a laser head (1) slidably arranged on the gantry of a gantry cutting machine. The sliding direction of the laser head (1) along the gantry is defined as the transverse direction, and the horizontal direction perpendicular to the transverse direction is defined as the longitudinal direction. A loading platform (5) is provided below the laser head (1), and a workpiece (4) is placed on the loading platform (5). Electric field generating devices (3) are symmetrically arranged at both ends of the workpiece (4) along the transverse direction, and the two electric field generating devices (3) clamp and fix the workpiece (4). The electric field generating device (3) includes a pressure sensor (302), a pneumatic device (301), an electrode (307), a spring (303), and a conductive core (305) arranged in sequence along the transverse direction. The conductive core (305) is made of a conductive material, and the spring (303) is made of an insulating material. The pneumatic device (301) is a cylinder, the base of the cylinder is connected to the pressure sensor (302), and the end of the output shaft of the cylinder is connected to a clamping disc (308). A through hole is coaxially arranged in the clamping disc (308) with the cylinder. A spring (303) and an electrode (307) are connected at the end of the output shaft of the cylinder and located inside the through hole. The electrode (307) is sleeved inside the spring (303), and the other end of the spring (303) is connected to the conductive core (305). A distance is left between the electrode (307) and the conductive core (305), and the electrode (307) can contact the conductive core (305) after the spring (303) is compressed, so as to control the generation of the electric field. A sleeve (306) is sleeved outside the conductive core (305), and the sleeve (306) is made of an insulating material. A limiting step (309) is arranged in the clamping disc (308), and a plurality of wedge-shaped baffles (304) matching with the limiting step (309) are arranged on the sleeve along the circumferential direction. The wedge-shaped baffles (304) can pop out or be pressed into the sleeve (306), and the wedge-shaped baffles (304) are used to prevent the sleeve (306) from being pushed out of the clamping disc (308) by the spring (303). On both sides of the laser head (1) symmetrically along the transverse direction, longitudinal guide rails are provided, and a magnetic field generating device (2) is slidably connected to the longitudinal guide rails; the magnetic field generating device (2) includes a cylindrical outer shell (201) arranged longitudinally, the outer shell (201) is made of insulating material, and a trapezoidal suspension slider (207) matched with the longitudinal guide rails is provided on the outer shell (201); two planetary gear mechanisms are arranged longitudinally in the outer shell (201), and the two planetary gear mechanisms are arranged opposite to each other; the planetary gear mechanism includes a sun gear (202), a ring gear (204), a planetary carrier and four planetary gears (203) supported on the planetary carrier; a large coil (206) and four small coils (208) are arranged between the two planetary gear mechanisms, the large coil (206) is fixed on a large magnetic core shaft, and the small coil (208) is fixed on a small magnetic core shaft; both ends of the large magnetic core shaft are fixedly connected to the sun gears (202) of the corresponding planetary gear mechanisms, and both ends of the small magnetic core shaft are fixedly connected to the planetary gears (203) of the corresponding planetary gear mechanisms; the sun gear (202) of one of the planetary gear mechanisms is connected to the output shaft of the motor; the large coil (206) rotates with the sun gear (202), the small coil (208) rotates with the planetary gear (203), and the large coil (206) and the small coil (208) rotate in opposite directions, thereby generating a sinusoidal alternating magnetic field; The electric field generating device (3) and the magnetic field generating device (2) are respectively electrically connected to a power supply.

2. The electromagnetic field-assisted thick plate laser cutting device according to claim 1, wherein: The spring (303) is of a frustum-shaped structure. The pitch of the part of the spring (303) close to the pneumatic device (301) is 10 mm, the number of turns is 20, and the diameter is 5 mm; the pitch of the part of the spring (303) close to the conductive core (305) is 8, the number of turns is 10, and the diameter is 5 mm.

3. An electromagnetic field-assisted thick plate laser cutting device according to claim 1, characterized in that: The magnetic field range of the sinusoidal alternating magnetic field is 5T to 20T, and the difference of the sinusoidal magnetic field fluctuates within the range of 0.5T to 1T; the reduction ratio of the planetary gear mechanism is 1:

2.

4. An electromagnetic field-assisted thick plate laser cutting device according to claim 1, characterized in that: The applicable frequency range of the power supply is 0 to 100HZ, and the waveform is a sine wave, a square wave or a sawtooth wave.

5. The electromagnetic field-assisted thick plate laser cutting device according to claim 1, characterized in that: A protective gas device is coaxially arranged in the laser head (1), and the protective gas output by the protective gas device is nitrogen or air, and the air pressure range is 0.5MPa to 10Mpa.

6. The electromagnetic field-assisted thick plate laser cutting device according to claim 1, characterized in that: The large coil (206) and the small coil (208) are wound with copper wires or copper tubes.

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