CN109128502B - Device and method for synchronously assisting laser welding through rotating electromagnetic field - Google Patents
Device and method for synchronously assisting laser welding through rotating electromagnetic field Download PDFInfo
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- CN109128502B CN109128502B CN201811201482.1A CN201811201482A CN109128502B CN 109128502 B CN109128502 B CN 109128502B CN 201811201482 A CN201811201482 A CN 201811201482A CN 109128502 B CN109128502 B CN 109128502B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/20—Bonding
- B23K26/21—Bonding by welding
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/12—Working by laser beam, e.g. welding, cutting or boring in a special atmosphere, e.g. in an enclosure
- B23K26/123—Working by laser beam, e.g. welding, cutting or boring in a special atmosphere, e.g. in an enclosure in an atmosphere of particular gases
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
- B23K26/702—Auxiliary equipment
Abstract
The invention discloses a device and a method for laser welding assisted by rotating electric-magnetic field synchronization, belonging to the field of laser welding. The invention can realize simple, convenient and rapid continuous adjustment of the rotary magnetic field and the constant electric field and the intensity, ensures the synchronous movement of the electric field and the magnetic field along with the welding laser beam, and improves the forming quality of the welding seam of the laser welding by setting reasonable laser process parameters such as power, focal length, defocusing amount, helium protective gas flow and the like.
Description
Technical Field
The invention belongs to the technical field of laser processing, and relates to a rotating electric-magnetic field synchronous auxiliary laser welding device and method, in particular to a permanent magnet-based rotating magnetic field and constant electric field joint synchronous auxiliary laser welding method and a welding device thereof.
Background
The laser welding is a welding method which adopts continuous or pulse laser beams as a heat source to melt and connect workpieces, and has the characteristics of high welding speed, large depth-to-width ratio, small deformation and the like. With the rapid development of industrial production and the continuous development of new materials, the requirements on the performance of a welding structure are higher and higher, and laser welding is widely applied with the advantages of high energy density, deep penetration, high precision, strong adaptability and the like.
The electro-magnetic field auxiliary welding technology is a new technology developed in recent years, and the electro-magnetic field auxiliary welding method is one of effective ways for improving weld formation and improving weld texture performance. Before the liquid metal in the molten pool is solidified to form a welding seam, the liquid metal is influenced by complex factors such as surface tension, electro-magnetic force, gravity and the like and can present a certain flowing state. In the welding process without external assistance, the forming defects such as uneven distribution of components and temperature fields, downward flowing, hump welding beads and the like are easily generated. After the external rotating electric-magnetic field is applied, the external rotating electric-magnetic field interacts with an electrofluid in a molten pool under the action of electro-magnetic induction, and the generated electric-magnetic force can change the flow of the molten pool and reduce the segregation of chemical components in a welding seam, so that the temperature distribution of the welding molten pool is uniform, the grain refinement is achieved, the generation of cracks and air holes is inhibited, and the effects of welding defects such as undercut, hump welding bead, air holes, cracks and the like during fusion welding are solved.
Because the forming mechanism of the welding pool under the action of external electricity and magnetism is extremely complex, the action mechanisms of physical fields such as heat, force, electricity and magnetism in the welding process are not thoroughly analyzed. The existing magnetic field auxiliary laser welding device is completed under test conditions, and the actual utilization value is not high. The externally applied magnetic field is asynchronous with the welding process, the consistency of the size, direction and frequency of the magnetic field at the molten pool in the laser welding process cannot be ensured, and the welding device is complex. Accordingly, there remains a need in the art for an apparatus for improving the quality of weld formation using an electro-magnetic field.
Chinese patent CN103612019B discloses a magnetic stirring CO2 laser-TIG electric arc hybrid welding method, which increases a longitudinal magnetic field on the basis of CO2 laser-TIG electric arc hybrid welding to realize the functions of grain refinement of a welding structure and improvement of energy coupling efficiency, but can not ensure that the magnetic field intensity acting on a molten pool is always kept consistent along with the progress of welding, and when the welding length exceeds a certain distance, the effect of an auxiliary magnetic field can not reach an ideal state. The invention assists the electric and magnetic fields to move synchronously with the welding laser beam, and ensures the electric and magnetic fields acting on the welding pool to be consistent all the time and the long-distance welding.
Chinese patent CN206824828U discloses an excitation moving platform for magnetic field assisted laser-arc hybrid welding, which realizes positioning and clamping of workpieces and also realizes magnetic field adjustment of a weld zone; although a servo motor in the device can enable a workpiece to move at a constant speed along with a welding laser beam in the welding process, the servo motor cannot be completely synchronous in motion, and cannot enable the consistency of the size, the direction and the frequency of a magnetic field acting on a welding molten pool area, when the size of the welding workpiece exceeds the size of an excitation moving platform, the use of the device is limited, and the clamping and dismounting processes of the workpiece are complex and cannot be automatically realized. The invention not only achieves the effect of the patent, but also can clamp the workpiece on the worktable of the welding machine tool without using the positioning and clamping tool when the size of the welded workpiece is overlarge, only the insulation between the workpiece and the worktable of the machine tool is ensured, and the effect of electromagnetic auxiliary laser welding can be achieved by connecting one pole of the power supply originally connected with the electric field generating bottom plate of the invention to the workpiece.
Disclosure of Invention
The invention aims to provide a special welding device and a special welding method for electro-magnetic synchronous auxiliary laser welding, which provide a synchronous rotating magnetic field and apply a vertical longitudinal electric field to play a magnetic stirring role on a molten pool together through a neodymium iron boron permanent magnet and a direct drive motor so as to solve the problems of forming quality of a laser welding joint and the like.
The invention adopts the following technical scheme: a method for synchronously assisting laser welding by rotating electromagnetic field is characterized in that during laser welding, an alternating magnetic field and a constant electric field are applied to act on a welding molten pool together, magnetic lines of force of the magnetic field acting on the molten pool are always vertical to the direction of a laser beam, and the direction of the electric field is parallel to the direction of the laser beam.
Wherein the region with the maximum magnetic field intensity always acts on a welding pool, the magnetic field intensity is 0-70 mT, the magnetic field rotation speed of the alternating magnetic field is 0-600 r/min, and the electric field voltage is 0-60V;
wherein, laser power P is 1500W, welding speed V is 600mm/min, adopts the mist of helium and argon as protective gas, and the protective gas flow: flow rate of helium f110L/min, argon flowIs f115L/min, and 0mm defocusing amount △ f.
A device for synchronously assisting laser welding by rotating an electromagnetic field comprises a CO2 laser, a laser reflection system, a machine tool motion system, a machine tool numerical control operation system, an encoder, a positioning and clamping tool, an electromagnetic adjusting device, a pneumatic valve manual switch, helium and argon gas cylinders, a power supply, a CO2 laser, a laser reflection system, a machine tool motion system, a machine tool numerical control operation system, a pneumatic valve manual switch, a helium and argon gas cylinder, a power supply2The laser beam emitted by the laser passes through the laser reflection system and is focused on the upper surface of a workpiece through the welding laser head, the machine tool numerical control operating system controls the motion of the machine tool motion system, the electromagnetic adjusting device is arranged on a main shaft of the machine tool motion system, the encoder controls the rotating speed of a direct drive motor arranged on the main shaft of the machine tool motion system, the positioning and clamping tool is arranged on a machine tool working table surface of the machine tool motion system, the pneumatic valve manual switch is connected on a rotary cylinder of the positioning and clamping tool through a gas circuit, thereby controlling the working state of the positioning and clamping tool, connecting helium and argon gas cylinders on the laser welding head, thereby protecting the welding pool, two poles of the power supply are respectively connected on the welding laser head and the electric field generation bottom plate of the positioning and clamping tool, thereby generating an electric field which can act on the welding pool and controlling the intensity of the electric field through the voltage output by the power supply.
Wherein the electro-magnetic adjustment device comprises: magnetic field adjusting device, electric field adjusting device, magnetic field adjusting device includes: the device comprises a direct drive motor, a magnetic field adjusting disk, a neodymium iron boron permanent magnet and a neodymium iron boron permanent magnet fixing shell, wherein the neodymium iron boron permanent magnet is wrapped by the neodymium iron boron permanent magnet fixing shell, the neodymium iron boron permanent magnet fixing shell is fastened on the magnetic field adjusting disk, the magnetic field adjusting disk is fastened on the direct drive motor, and the direct drive motor is fastened on a main shaft of a machine tool motion system by a positioning pin and an inner hexagon screw; the electric field adjusting device includes: welding laser head, insulating cover, power, electric field take place bottom plate, insulating cushion, and the tight frock of positioning clamp includes: the electric field generator comprises a bottom plate, supporting columns, a rotary cylinder, an electric field generation bottom plate, an insulation bushing, a pressing block and a workpiece pressing block, wherein the supporting columns and the rotary cylinder are assembled on the bottom plate, the insulation bushing is assembled on the electric field generation bottom plate, the insulation bushing and the electric field generation bottom plate are assembled on the supporting columns together, the pressing block is assembled on the rotary cylinder, and the workpiece pressing block is assembled on the pressing block.
The magnetic field adjusting device comprises a magnetic field adjusting disc, a direct-drive motor, a neodymium iron boron permanent magnet and a permanent magnet fixing shell, the magnetic field adjusting disc is directly locked on the direct-drive motor rotor shell through a positioning pin and an inner hexagon screw, and a graduated scale and a T-shaped groove are processed on the magnetic field adjusting disc and are respectively used for adjusting the magnetic field intensity and fastening the neodymium iron boron permanent magnet.
The permanent magnet fixing shell is made of permalloy, and the neodymium iron boron permanent magnet is wrapped by the permanent magnet fixing shell and is fastened on the magnetic field adjusting plate.
Wherein the electric field adjusting device includes: the welding laser head, the insulating sleeve, the power supply, the electric field generating bottom plate and the insulating cushion block are in threaded connection, and when the welding laser head, the flange plate of the direct drive motor and the insulating sleeve are assembled together, the through holes of the through wires are ensured to be coaxial; the lead sequentially penetrates through the welding laser head, the insulating sleeve and the flange plate of the direct drive motor, one end of the lead is brazed on the welding laser head, one end of the lead is connected to one pole of a power supply, and the other pole of the power supply is connected to the electric field generation bottom plate or a workpiece.
An insulating cushion block is arranged between the workpiece and the electric field generation bottom plate, so that current is not led into the welding workpiece, and a uniform electric field is generated between the electric field generation bottom plate and the welding laser head and acts on a welding pool.
Wherein, the positioning and clamping tool comprises a bottom plate, a support column, a rotary cylinder, a pressing block, an insulating bush and an electric field generation bottom plate, and meets the assembly requirements: the supporting columns are fixed on the bottom plate, the rotary air cylinder is fastened on the bottom plate through the positioning pins and the inner hexagon screws and is connected with the pneumatic valve manual switch in the external air circuit, and the on-off of the air circuit can be controlled through the electromagnetic valve in automatic production to control the working state of the rotary air cylinder. The pressing block is arranged on a piston rod of the rotary cylinder; the insulating bush and the electric field generation bottom plate are assembled together in an interference fit mode, the insulating bush and the rotary cylinder piston rod are in clearance fit, the electric field generation bottom plate is fixed on the supporting column through the hexagon socket head cap screw, and the electric field generation bottom plate and the rotary cylinder are guaranteed to have a clearance larger than 0.5 mm.
The bottom plate and the support columns are made of acrylic, the insulating sleeve is made of bakelite, and the insulating cushion blocks and the insulating bushings are made of marble so as to ensure the insulation and high-temperature resistance of the parts; and fixing the positioning and clamping tool on the machine tool workbench by adopting the pressing plate, the pressing plate supporting block, the inner hexagon screw and the T-shaped nut.
The principle of the invention is as follows: in order to achieve the above objects and to overcome the limitations and disadvantages of the prior art, an improved electrical and magnetic assisted laser welding system comprises: the device comprises a CO2 laser 1, a laser reflection system 2, a numerically-controlled machine tool motion system 3, a numerically-controlled machine tool operation system 4, an encoder 5, a positioning and clamping tool 6, an electromagnetic adjusting device 7, a pneumatic valve manual switch 8, a helium and argon gas cylinder 9 and a power supply 10. And the electro-magnetic adjustment means 7 mainly comprise: the device comprises an encoder 5, a power supply 10, a magnetic field adjusting plate 11, a neodymium iron boron permanent magnet fixing shell 12, an electric field generation bottom plate 24, a welding laser head 25 and a direct drive motor 26. The positioning and clamping tool 6 mainly comprises: pneumatic valve hand switch 8, briquetting 13, insulating bush 14, work piece briquetting 17, gyration cylinder 23, bottom plate 20, support column 22.
The CO2 laser 1 generates laser, the laser reflection system 2 transmits the generated laser to a machine tool spindle of a numerical control machine tool motion system 3, and a welding laser head 25 fastened on the machine tool spindle focuses the laser on a workpiece 16. The machine tool numerical control operating system 4 controls the movement of the machine tool moving system 3, the helium and argon gas cylinders 9 are connected to the welding laser head 25, and coaxial shielding gas is adopted during welding. A magnetic field adjusting device in the electromagnetic adjusting device 7 is fastened on a machine tool main shaft of the machine tool moving system 3, and an electric field generating power supply 10 and a positioning and clamping tool 6 in the electric field adjusting device are fastened on a machine tool workbench of the machine tool moving system 3.
The positioning and clamping tool is used for positioning and clamping a workpiece and is integrally assembled as shown in figure 3. In which the base plate 20 is fixed to a machine table 21.
In this example, 4 rotary cylinders 23 and 4 support columns 22 are fixed to the base plate 20. (the specification of the rotary cylinder 23 can be selected according to the actual processing technology requirements.)
The electric field generation base plate 24 is fixed on the support column 22
The pressure piece 13 is fixed on the piston rod of the rotary cylinder 23. The workpiece pressing block 17 can be assembled on the pressing block 13 through self-provided threads.
Further the optional ya keli is as the material of support column 22, in order to prevent that the electric current from passing into the lathe workstation. Support column 22 is first secured to base plate 20 by M8 socket head cap screws, which are countersunk into base plate 20.
Further, the upper end faces of the assembled support columns 22 can be milled flat on a milling machine, so that the upper end faces of the four support columns 22 are ensured to be in the same plane, and the assembly precision of the subsequent electric field generation base plate 24 is ensured.
Further, the rotary cylinder 23 may be fixed to the base plate 20 by a positioning pin and M6 socket head cap screws.
Further optional ya keli is as the material of bottom plate 20, chooses for use insulating material in order to further guarantee the safety of laser welding course of working. Then, the two ends of the bottom plate 20 are locked on the T-shaped groove through the inner hexagon screws, the T-shaped nuts, the pressure plate 18 and the supporting blocks 19, so that the bottom plate 20 is tightly pressed and fixed on the machine tool workbench.
Further, marble can be selected as the material of the insulating bush 14, so that high temperature resistance and insulation of the bush are guaranteed, and current is prevented from flowing into the rotary cylinder 23. The field generating substrate 24 and the insulating bush 14 are assembled together, and the insulating bush 14 is fixed to the field generating substrate 24 by interference fit.
Further, the clearance fit between the piston rod of the rotary cylinder 23 and the insulation bushing 14 is ensured, the piston rod of the rotary cylinder 23 is ensured not to contact with the insulation bushing 14, reciprocating rotation can be freely performed, abrasion is avoided, and the movement precision is ensured. Assembled as in figure 4.
Further, the electric field generating base plate 24 can be fixed on the supporting column 22 by M8 socket head cap screws, and the height of the supporting column 22 is 0.5mm higher than the shell of the revolving cylinder 23. The electric field generation bottom plate 24 is ensured not to be contacted with the shell of the rotary cylinder 23, and the current is ensured not to be led into the cylinder.
Furthermore, grooves are formed in the electric field generation bottom plate 24, and damage of laser to the electric field generation bottom plate 24 is avoided. The welding workpiece 16 and the electric field generating base plate have an insulating spacer block for ensuring that current is not introduced into the welding workpiece 16 and a uniform electric field is generated between the electric field generating base plate 24 and the welding laser head 25. (in the actual production process, corresponding tool fixtures can be designed according to the specific geometric shapes of the machined workpieces, for example, a curved-surface shell structure tool is designed as shown in fig. 5, only the machined curved-surface workpiece 28 is matched with a semi-cylindrical-structure tool 29 in fig. 5, then the rotary cylinder 23 is in a working state, and the curved-surface workpiece pressing block 30 presses the workpiece tightly.)
Furthermore, the pressing block 13 can be fixed on the piston rod of the rotary cylinder 23 by using M4 socket head cap screws. The workpiece pressing block 17 can be assembled on the pressing block 13 through self-provided threads. (briquetting 13 and workpiece briquetting 17 are preferably stainless steel briquettes supplied by manufacturers, and the size and geometry of the workpiece briquetting can be designed according to actual process requirements, such as tooling 28, curved workpiece 29 and curved workpiece briquetting 30.)
The electric-magnetic field regulating device is used for generating electric and magnetic fields. Wherein the magnetic field adjusting disk 11 is fixed on the direct drive motor 26.
The ndfeb permanent magnet can be fastened to the magnetic field adjusting disk as shown in fig. 6 by fixing the housing 12 with the ndfeb permanent magnet of a thin shell structure.
The welding laser head 25 is fixed to an insulating sleeve 27. The insulating sleeve 27 is fixed on the flange of the direct drive motor 26.
The power supply 10 is connected to the welding laser head 25 at one end and to the electric field generating base plate 24 at the other end.
Further, a positioning pin hole of phi 6 and a counter bore of M8 are processed on the flange of the direct drive motor 26 for fixing the direct drive motor 26 on the main shaft of the numerical control machine tool. Pipe threads are machined on the surface of a central hole of the flange plate, an inner hole communicated with a lead phi 3 is formed in the side face of the flange plate, and the structural schematic diagram of the flange plate of the direct drive motor is shown in figure 7.
Further, the outer surface of the upper end of the welding laser head is processed with pipe threads, and a hole with a lead phi 3 is processed on the welding laser head as shown in figure 8.
Further, the insulating sleeve 27 is made of bakelite, and the inner and outer surfaces are provided with threads and holes for conducting wires phi 3 as shown in fig. 9. The external thread is in threaded connection with the inner hole pipe in the center of the flange plate of the direct drive motor, and the insulating sleeve 27 is fixed on the flange plate. The internal thread of the insulating sleeve 27 is in threaded connection with the welding laser head. Then, the lead sequentially passes through the welding laser head 25, the insulating sleeve 27 and the flange of the direct drive motor 26 to be connected with the power supply 10, and meanwhile, the lead is brazed on the welding laser head 25 by means of brazing, so that the welding laser head 25 is ensured to be conducted with the power supply 10.
Further the other pole of the power supply 10 is connected to an electric field generating substrate 24.
Further, the positioning pin hole of phi 5 on the magnetic field adjusting disk 11 and the countersunk hole of M5 are used to directly fix the magnetic field adjusting disk on the direct drive motor 26. And a T-shaped groove is formed on the magnetic field adjusting disk 11 and used for fixing the neodymium iron boron permanent magnet. The magnetic field adjusting disk 11 is provided with a scale for adjusting the magnitude of the magnetic field as shown in fig. 10. The diameter of the central hole of the adjusting disk is 3mm larger than the diameter of the welding laser head 25. Preventing the passage of electric field current from the welding laser head 25 to the magnetic field generating means.
Further, the fixed housing 12 for fixing the ndfeb permanent magnet tightly wraps the ndfeb permanent magnet, and then is fixed on the magnetic field adjusting disk 11 through an M5 screw. It can be made of permalloy, ensuring good magnetic conduction effect. The position of the neodymium iron boron permanent magnet on the magnetic field adjusting disk 11 is adjusted to adjust the magnetic field intensity, the maximum position of the field intensity can be measured by using a magnetic field intensity tester, the strongest point of the magnetic field is overlapped with a welding molten pool, the magnetic force line acting on the molten pool is in the horizontal direction, and the magnetic field intensity can be adjusted within the range of 0-70 mT.
The distance between the two Nd-Fe-B permanent magnets and the laser beam can be adjusted, so that the magnetic force lines acting on the molten pool and the welding laser beam form a certain angle. The direct drive motor 26 is fastened on a machine tool spindle of the machine tool motion system 3, so that a magnetic field generated in the welding movement process and a welding molten pool are kept relatively static, and the size and the direction of the magnetic field acting on the molten pool are kept consistent.
The constant electric field in the vertical direction generated between the welding laser head 22 and the two poles of the electric field generation base plate 24 can be adjusted in the electric field intensity by adjusting the output voltage of a power supply connected with the constant electric field, the voltage adjusting range is 0-60V, and the change of the electric field direction can be realized by adjusting and connecting a power supply electrode.
In summary, the present invention has the following beneficial effects:
(1) the invention can not only realize the lap joint of the rotating electric-magnetic field, but also realize that the constant electric field and the rotating magnetic field act on the welding pool independently, and can also realize that the independent constant magnetic field acts on the welding pool.
(2) Besides single-field auxiliary laser welding, multi-field (rotating magnetic field and constant electric field, constant magnetic field and constant electric field) can be jointly acted on a welding pool, and the electromagnetic adjusting device is simple to operate and convenient and flexible to adjust.
(3) The auxiliary rotating electromagnetic field moves synchronously with the welding laser beam, the welding pool is welded under the synchronous action of the auxiliary rotating electromagnetic field and the laser beam, and the enhanced welding pool is stressed in the magnetic field to generate stronger electromagnetic force to drive the welding pool to flow, so that the electromagnetic stirring effect is enhanced, the heat transfer and convection of liquid metal in the welding pool are enhanced, the temperature field and solute in the welding pool are homogenized, and the effects of refining grains, reducing pores and cracks, improving the collapse of the welding pool and the like are achieved.
(4) Meanwhile, the positioning and clamping tool can realize rapid positioning and clamping of the workpiece. The invention can be used in various working conditions. The invention provides important reference value for the application of electric-magnetic field assisted laser welding in experimental research and engineering automation.
Drawings
FIG. 1 is a schematic view of a rotary electro-magnetic synchronous auxiliary laser welding device according to the present invention.
Fig. 2 is a schematic view of an electro-magnetic adjustment apparatus of the present invention.
Fig. 3 is a schematic view of a positioning and clamping tool for laser welding of a sheet workpiece according to the present invention.
FIG. 4 is a schematic view of the assembly of the rotary cylinder with the insulating bushing of the present invention.
FIG. 5 is a schematic view of a positioning and clamping tool for laser welding of curved workpieces according to the present invention.
FIG. 6 is a schematic view of a magnetic field adjusting device according to the present invention.
Fig. 7 is a schematic view of a flange of the direct drive motor of the present invention.
Fig. 8 is a schematic view of a welding laser head according to the present invention.
Fig. 9 is a schematic view of an insulating sleeve according to the present invention.
Fig. 10 is a view showing the magnetic field control plate of the present invention, the upper view is a bottom view of the magnetic field control plate, and the lower view is a front view.
FIG. 11 is a scanning electron microscope photograph of the cross section of the welded joint obtained by welding in example 1.
FIG. 12 is a scanning electron microscope photograph of the cross section of the welded joint obtained by welding in example 2.
FIG. 13 is a scanning electron microscope photograph of the cross section of the welded joint obtained by welding in example 3.
FIG. 14 is a scanning electron microscope photograph of the cross section of the welded joint obtained by welding in example 4.
In the figure: 1 is a CO2 laser; 2 is a laser reflection system; 3, a machine tool motion system; 4, a machine tool numerical control operating system; 5 is an encoder; 6, positioning and clamping tools; 7 is an electromagnetic adjusting device; 8 is a pneumatic valve manual switch; 9 is helium and argon gas cylinder; 10 is a power supply; 11 is a magnetic field adjusting disc; 12 is a neodymium iron boron permanent magnet fixed shell; 13 is a pressing block; 14 is an insulating bush; 15 is an insulating cushion block, and 16 is a workpiece; 17 is a workpiece pressing block; 18 is a pressure plate, 19 is a supporting block; 20 is a bottom plate; 21 is a machine tool workbench; 22 is a support column; 23 is a rotary cylinder; 24 is an electric field generating bottom plate; 25 is a welding laser head; 26 is a direct drive motor; 27 is an insulating sleeve; 28 is a curved surface tool; 29 is a curved surface workpiece; 30 is a curved workpiece pressing block.
Detailed Description
So that the manner in which the features, aspects and advantages of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. In addition, the embodiments described herein are only for explaining the gist of the present invention, and are not intended to limit the present invention, and the present invention may be suitably modified according to a specific practical use case.
Referring to fig. 1 to 9, the present invention provides a rotating electro-magnetic field synchronous auxiliary laser welding apparatus and method. The individual devices in this case can be modified according to the specific geometric shape of the actual welded workpiece, as will be briefly described in the following embodiments, but in order to ensure the safety of the actual machining process for the parts made of insulating materials such as acrylic and marble, the modified devices should also have an insulating effect and meet the corresponding requirements of the assembly process.
Firstly, the assembly work of the electro-magnetic adjusting device 7 is performed before welding, and secondly the welding work of the sheet metal parts is performed. The whole assembly process and the process requirements are as follows:
the positioning and clamping tool is used for positioning and clamping a workpiece. The number of the rotary cylinders 23 in the embodiment is 4, in the embodiment, the SMC type MKB32 rotary cylinder 23 can be selected, the rotary cylinder 23 is fixed on the bottom plate 20 through a positioning pin and an M6 hexagon socket head cap screw, the bottom plate 20 can be made of acrylic, electric field generated current is prevented from being led into the machine tool workbench 21, and the safety of welding work is ensured.
The support post 22 is then secured to the base plate 20 using M8 socket head cap screws which are countersunk into the base plate 20. The support column 22 can be made of acrylic material, and the insulating material is selected to further ensure the safety of the laser welding process and prevent current from passing into the machine tool workbench. And secondly, fixing the bottom plate 20 on a machine tool workbench 21 by using a pressure plate 18, a supporting block 19, a socket head cap screw and a T-shaped nut.
Further, the upper end faces of the assembled support columns 22 can be milled flat on a milling machine, so that the upper end faces of the four support columns 22 are ensured to be in the same plane, and the assembly precision of the subsequent electric field generation base plate 24 is ensured. While ensuring that the height of the support column 22 is 0.5mm higher than the height of the revolving cylinder 23. When the electric field generation bottom plate 24 is arranged on the supporting column 22, the electric field generation bottom plate 24 is not contacted with the rotary cylinder 23, and current is not introduced into the cylinder.
The field generating substrate 24 and the insulating bush 14 are assembled together, and the insulating bush 14 is fixed to the field generating substrate 24 by interference fit. Further, marble can be selected as the material of the insulating bush 14, so that high temperature resistance and insulation of the bush are guaranteed, and current is prevented from flowing into the rotary cylinder 23.
Then the insulation bushing 14 and the electric field generation bottom plate are assembled on the piston rod of the rotary cylinder 23, and further, the clearance fit between the insulation bushing 14 and the piston rod of the rotary cylinder 23 is ensured, so that the piston rod of the rotary cylinder 23 is not contacted with the insulation bushing 14, the piston rod can freely do reciprocating rotation movement, no abrasion is generated, and the movement precision is ensured.
And then the electric field generation bottom plate 24 is fixed on the supporting column 22 through an M8 socket head cap screw, and further a groove is formed in the electric field generation bottom plate 24 to prevent the electric field generation bottom plate 24 from being damaged by laser. Meanwhile, the welding workpiece 16 and the electric field generation bottom plate are provided with an insulating cushion block, so that the current is not led into the welding workpiece 16, and a uniform electric field is generated between the electric field generation bottom plate 24 and the welding laser head 25 and is used as a welding pool.
In the case of a press block 13 which can be fastened to the piston rod of the rotary cylinder 23 by means of M4 socket head cap screws, the workpiece press block 17 can be fitted to the press block 13 by means of its own thread.
Then, the phi 5 positioning pin hole and the M5 countersunk hole on the magnetic field adjusting disk 11 are used for directly fixing the magnetic field adjusting disk on the direct drive motor 26. Further, a T-shaped groove is formed in the magnetic field adjusting disc 11 and used for fixing the neodymium iron boron permanent magnet. The magnetic field adjusting disk 11 is provided with a graduated scale for adjusting the size of the magnetic field. The diameter of the central hole of the adjusting disk is 3mm larger than the diameter of the welding laser head 25. Preventing the passage of electric field current from the welding laser head 25 to the magnetic field generating means.
The shell 12 is fixed to neodymium iron boron permanent magnet accessible thin shell structure's neodymium iron boron permanent magnet, wraps up it to adopt M5 hexagon socket head cap screw, fasten it on magnetic field adjustment dish. Further, the fixing case 12 for fixing the ndfeb permanent magnet may be made of permalloy in order to ensure a good magnetic conduction effect. It is fixed to the disk 11 by means of M5 screws.
The insulating sleeve 27, the direct drive motor 26 and the welding laser head 25 are in threaded connection, and the insulating sleeve 27 is fastened on a flange of the direct drive motor 26. The welding laser head 25 is then fastened to the insulating sleeve 27. Further, the insulating sleeve 27 is made of bakelite, and the inner surface and the outer surface of the insulating sleeve are provided with threads and holes for leading through a wire phi 3. The external thread is in threaded connection with the inner hole pipe in the center of the flange plate of the direct drive motor, and the insulating sleeve 27 is fixed on the flange plate. The internal thread of the insulating sleeve 27 is matched and fixed with the welding laser head. Then, the lead sequentially passes through the welding laser head 25, the insulating sleeve 27 and the flange of the direct drive motor 26 to be connected with the power supply 10, and meanwhile, the lead is brazed on the welding laser head 25 by means of brazing, so that the welding laser head 25 is ensured to be conducted with the power supply 10.
Finally, the power source 10 is soldered at one end to the welding laser head 25 and at the other end to the field generating substrate 24. The direct drive motor 26 is then fixed to the spindle of the numerical control machine. Then, the welding work of the sheet member is performed.
Example 1: electric-magnetic field assisted laser welding industrial pure nickel Ni201
Firstly, wiping a plurality of dirt such as oil stain on the surface of industrial pure nickel Ni201 to be welded with acetone, blowing dry with air after wiping, and keeping dry and clean. Industrial pure nickel is placed on the electric field generation bottom plate, and the switching between the working states of the rotary cylinder 23 can be realized by controlling a pneumatic valve manual switch 8 (an electromagnetic valve can be adopted in automatic production to control the on-off of the gas circuit) in an external gas circuit connected with the rotary cylinder 23. The cylinder is switched to the operating mode, as shown in fig. 2, in the clamping operation of the revolving cylinder 23.
Secondly, setting welding parameters of the numerical control welding industrial pure nickel: laser power P is 1500W, welding speed V is 600mm/min, a mixed gas of helium and argon is used as a shielding gas, and the flow of the shielding gas is adjusted: flow rate of helium f110L/min, argon flow f1Adjusting the defocusing amount △ f of the laser at 15L/min0mm focuses the laser beam on the workpiece surface.
The magnetic field is then adjusted according to the magnetic field strength requirements in this embodiment, and the region of greatest strength is applied to the weld pool. Firstly, unscrewing a screw for fixing the neodymium iron boron permanent magnet, then adjusting the position of a fastening bolt in a T-shaped groove, and testing the magnetic field intensity at the laser focusing position by using a magnetic field intensity tester to enable the magnetic field intensity to be tested to be 30 mT. And then setting parameters of the encoder 8 and controlling the rotating speed of the direct drive motor 26 to be 600 r/min. The electric field does not act on the weld pool.
Finally, the CO2 laser is started to weld the industrial pure nickel Ni 201. After the welding is finished, the pneumatic valve manual switch 8 is adjusted to lift the piston of the rotary cylinder 23, the workpiece pressing block 17 leaves the surface of the workpiece, and the workpiece is taken down. A metallographic sample piece is cut on the cross section of the sample piece along the direction perpendicular to the welding direction by linear cutting, the surface of the sample piece is ground and polished, the sample piece is corroded by nitric acid aqueous solution, the scanning electron microscope is adopted for observation, and the size of crystal grains is shown in figure 10.
Example 2
After the test case 1 is completed, a piece of processed industrial pure nickel is placed on the electric field generation bottom plate 24, and the pneumatic valve manual switch 8 is toggled, so that the workpiece pressing block 17 presses the workpiece 13. Loosening the screw for fixing the neodymium iron boron permanent magnet, shortening the distance between the two permanent magnets, testing the magnetic field intensity at the laser focusing position to be 70mT by using a magnetic field intensity tester, and setting the parameters of the encoder to control the rotating speed of the direct drive motor to be 200 r/min. The electric field does not act on the weld pool.
The CO2 laser was then activated to weld commercially pure nickel sheets. After the welding is finished, the pneumatic valve manual switch 8 is adjusted to lift the piston of the rotary cylinder 23, the workpiece pressing block 17 leaves the surface of the workpiece, and the workpiece is taken down. A metallographic sample piece is cut on the cross section of the sample piece along the direction perpendicular to the welding direction by linear cutting, the surface of the sample piece is ground and polished, the sample piece is corroded by nitric acid aqueous solution, the scanning electron microscope is adopted for observation, and the size of crystal grains is shown in figure 11.
After the test case 2 is completed, a piece of processed industrial pure nickel is placed on the electric field generation bottom plate 24, and the pneumatic valve manual switch 8 is toggled, so that the workpiece pressing block 17 presses the workpiece 13. The magnetic field intensity is still 70mT, and the rotating speed of the direct drive motor is controlled to be 600r/min by setting the parameters of the encoder. The power supply 10 is started and the output voltage is adjusted to 20V.
The CO2 laser was then activated to weld commercially pure nickel sheets. After the welding is finished, the pneumatic valve manual switch 8 is adjusted to lift the piston of the rotary cylinder 23, the workpiece pressing block 17 leaves the surface of the workpiece, and the workpiece is taken down. Cutting a metallographic sample piece on the cross section of the sample piece along the direction vertical to the welding direction by linear cutting, grinding and polishing the surface of the sample piece, corroding the sample piece by using a nitric acid aqueous solution, observing the sample piece by using a scanning electron microscope, and showing the grain size as shown in figure 12.
Example 4
After the test case 3 is completed, a piece of processed industrial pure nickel is placed on the electric field generation bottom plate 24, and the pneumatic valve manual switch 8 is toggled, so that the workpiece pressing block 17 presses the workpiece 13. The magnetic field intensity is still 70mT, and the rotating speed of the direct drive motor is controlled to be 600r/min by setting the parameters of the encoder. The power supply 10 is started and the output voltage is adjusted to 60V.
The CO2 laser was then activated to weld commercially pure nickel sheets. After the welding is finished, the pneumatic valve manual switch 8 is adjusted to lift the piston of the rotary cylinder 23, the workpiece pressing block 17 leaves the surface of the workpiece, and the workpiece is taken down. And cutting a metallographic sample piece on the cross section of the sample piece along the direction vertical to the welding direction by linear cutting, grinding and polishing the surface of the sample piece, corroding the sample piece by using a nitric acid aqueous solution, and observing the sample piece by using a scanning electron microscope, wherein the size of crystal grains is shown in figure 13.
As is apparent from fig. 9 to 12, the grain size is significantly refined as the electric and magnetic field strengths are increased and the rotation speed of the rotating magnetic field is increased.
The embodiment provides only a simple welding device and a method for conveniently welding thin plate parts. The simple and efficient electro-magnetic coupling field auxiliary laser welding device is provided, and the worktable surface and the clamp of the device can be matched to realize quick and accurate positioning and clamping of a workpiece. (in the actual working condition, according to the specific workpiece geometry, the design and the workpiece matching tool, fixed on the electric field generation bottom plate 24, and the selection of the appropriate rotary cylinder 23 as shown in figure 5, curved workpiece laser welding.)
The magnetic field adjusting device can quickly and conveniently realize the adjustment of the size and the direction of the magnetic field intensity, the continuous and uniform adjustment of the size of the magnetic field intensity is easy to realize, and the adjustment of an electric field can also be simply realized. Since the positions of the rotating electro-magnetic field and the welding laser beam are kept relatively stationary during the actual welding process, it is ensured that the magnitude and direction of the electro-magnetic field acting on the weld pool remain unchanged. The device has the advantages of simple structure, flexible operation and stronger practicability. The method can be applied to medium and small batch production, and can obtain ideal results when the influence of the rotating electromagnetic field on welding is researched in a laboratory.
The above embodiments are merely exemplary embodiments of the present invention, which is intended to provide the user with a better understanding of the present invention, and the present invention is not limited thereto.
Claims (2)
1. A device for laser welding is assisted in step to rotatory electricity-magnetic field which characterized in that: the device comprises a CO2 laser (1), a laser reflection system (2), a machine tool motion system (3), a machine tool numerical control operation system (4), an encoder (5), a positioning and clamping tool (6), an electromagnetic adjusting device (7), a helium and argon gas cylinder (9) and a power supply (10); CO22Laser beams emitted by a laser (1) pass through a laser reflection system (2) and are focused on the upper surface of a workpiece through a welding laser head, a machine tool numerical control operating system (4) controls the movement of a machine tool moving system (3), an electromagnetic adjusting device (7) is arranged on a main shaft of the machine tool moving system (3), an encoder (5) controls the rotating speed of a direct drive motor arranged on the main shaft of the machine tool moving system (3), a helium gas cylinder and an argon gas cylinder (9) are connected on a laser welding head so as to protect a welding molten pool, two poles of a power supply (10) are respectively connected on a welding laser head and an electric field generation bottom plate of a positioning clamping tool (6),thereby generating an electric field which can act on the welding pool, and controlling the intensity of the electric field through the voltage output by the power supply (10);
the electro-magnetic adjustment device (7) comprises: magnetic field adjusting device, electric field adjusting device, magnetic field adjusting device includes: the device comprises a direct drive motor (26), a magnetic field adjusting disk (11), a neodymium iron boron permanent magnet and a neodymium iron boron permanent magnet fixing shell (12), wherein the neodymium iron boron permanent magnet is wrapped by the neodymium iron boron permanent magnet fixing shell (12), the neodymium iron boron permanent magnet fixing shell (12) and the neodymium iron boron permanent magnet are fastened on the magnetic field adjusting disk (11), the magnetic field adjusting disk (11) is fastened on the direct drive motor (26), and the direct drive motor (26) is fastened on a main shaft of a machine tool motion system (3) by a positioning pin and an inner hexagon screw; the magnetic field adjusting disc (11) is directly locked on a rotor shell of the direct drive motor (26) by adopting a positioning pin and an inner hexagon screw, and a graduated scale and a T-shaped groove are processed on the magnetic field adjusting disc (11) and are respectively used for adjusting the magnetic field intensity and fastening a neodymium iron boron permanent magnet; the neodymium iron boron permanent magnet fixing shell (12) is made of permalloy;
the electric field adjusting device includes: welding a laser head (25), an insulating sleeve (27), a power supply (10), an electric field generation bottom plate (24) and an insulating cushion block (15), assembling the insulating cushion block (15) on the electric field generation bottom plate (24), and then assembling the insulating cushion block (15) on a support column (22); the welding laser head (25) and the insulating sleeve (27) as well as the insulating sleeve (27) and the flange of the direct drive motor (26) form threaded connection, and when the welding laser head (25), the insulating sleeve (27) and the flange of the direct drive motor (26) are assembled together, the through holes for passing through the wires must be ensured to be coaxial; a lead sequentially penetrates through the welding laser head (25), the insulating sleeve (27) and a flange of the direct drive motor (26), one end of the lead is brazed on the welding laser head (25), the other end of the lead is connected to one pole of the power supply (10), and the other pole of the power supply (10) is connected to the electric field generation bottom plate (24);
an insulating cushion block (15) is arranged between the workpiece (16) and the electric field generation bottom plate (24) to ensure that current is not introduced into the welding workpiece (16), and a uniform electric field is generated between the electric field generation bottom plate (24) and the welding laser head (25) and acts on a welding pool;
the positioning and clamping tool comprises a bottom plate (20), a supporting column (22), a rotary cylinder (23), a pressing block (13) and an insulating bush (14), wherein the supporting column (22) is fixed on the bottom plate (20), the rotary cylinder (23) is fastened on the bottom plate (20) by adopting a positioning pin and an inner hexagon screw and is connected with a pneumatic valve manual switch (8) in an external air path, and the working state of the rotary cylinder (23) is controlled; the pressing block (13) is arranged on a piston rod of the rotary cylinder (23); the insulation bushing (14) and the electric field generation bottom plate (24) are assembled together in an interference fit mode, the insulation bushing (14) is in clearance fit with a piston rod of the rotary cylinder (23), the electric field generation bottom plate (24) is fixed on the supporting column (22) through the hexagon socket head cap screw, and a clearance larger than 0.5mm is guaranteed between the electric field generation bottom plate (24) and the rotary cylinder (23); the bottom plate (20) and the supporting columns (22) are made of acrylic, the insulating sleeve (27) is made of bakelite, and the insulating bush (14) and the insulating cushion block (15) are made of marble so as to ensure the insulating and high-temperature resistant performance of parts; the positioning and clamping tool is fixed on a machine tool workbench (21) by adopting a pressure plate (18), a pressure plate supporting block (19), an inner hexagon screw and a T-shaped nut.
2. A method of rotary electro-magnetic field synchronous assisted laser welding using the rotary electro-magnetic field synchronous assisted laser welding apparatus of claim 1, characterized in that: during laser welding, an alternating magnetic field and a constant electric field are applied to act on a welding molten pool together, magnetic lines of force of the magnetic field acting on the molten pool are always perpendicular to the direction of a laser beam, and the direction of the electric field is parallel to the direction of the laser beam;
the area with the maximum magnetic field intensity always acts on a welding pool, the magnetic field intensity is 0-70 mT, the magnetic field rotation speed of the alternating magnetic field is 0-600 r/min, and the electric field voltage is 0-60V.
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| CN109967864A (en) * | 2019-05-05 | 2019-07-05 | 北京航空航天大学 | A kind of magnetic field assistant laser burnishing device based on existing laser process equipment |
| US11123826B1 (en) | 2020-03-11 | 2021-09-21 | Jiangsu University | Electromagnetic apparatus for active intervention to shape of molten pool |
| CN111455372B (en) * | 2020-03-11 | 2021-04-20 | 江苏大学 | Electromagnetic equipment for actively interfering molten pool morphology |
| CN112518095A (en) * | 2020-12-14 | 2021-03-19 | 浙江工业大学 | Special device for optimizing electron beam welding seam by external magnetic field pulse ultrasonic vibration |
| CN113385820B (en) * | 2021-06-11 | 2023-01-31 | 绍兴文理学院 | Double-magnetic-field and ultrasonic-wave cooperative auxiliary laser deep melting welding device |
| CN113560750B (en) * | 2021-07-20 | 2023-03-10 | 南京航空航天大学 | Flexible automatic clamping device and method for laser penetration welding of back of T-shaped structure |
| CN114260629A (en) * | 2022-01-18 | 2022-04-01 | 无锡品正机械科技有限公司 | Sheet metal welding clamping device |
| CN114905151B (en) * | 2022-05-25 | 2024-01-30 | 吉林大学 | 2219 aluminum alloy sheet electromagnetic auxiliary laser thermal conductive welding method |
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| CN201025588Y (en) * | 2006-01-13 | 2008-02-20 | 熊成锐 | A motive magnetic field generation device for controlling and dispersing harmful plasm in industrial production |
| CN101745747A (en) * | 2009-12-14 | 2010-06-23 | 大连理工大学 | Laser-electric arc composite welding method through extra electric field |
| JP2014121722A (en) * | 2012-12-21 | 2014-07-03 | Toyota Industries Corp | Laser welding method and laser welding apparatus |
| CN104195541B (en) * | 2014-08-11 | 2017-02-15 | 浙江工业大学 | Electric-magnetic compound field synergy laser-cladding method and device |
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| CN107252970A (en) * | 2017-07-04 | 2017-10-17 | 广东工业大学 | A kind of laser welding system and method |
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