Magnetic field generating device, additive manufacturing system and method of operation thereof

Abstract

The application belongs to the field of additive manufacturing and discloses a magnetic field generating device, which comprises a sleeve and three magnetic field generating mechanisms connected to the sleeve; the sleeve is arranged outside a welding gun, and an excitation coil is wound around the lower part of the sleeve; each magnetic field generating mechanism comprises a sliding block and a support arm connected to the sliding block, and the support arm comprises a first support arm and a second support arm; the first support arm is hingedly connected to the second support arm, and the first support arm is fixedly connected to the sliding block; a sliding groove is preformed on each of the first support arm and the second support arm, a connecting rod is arranged in the sliding groove, connecting plates are connected to the two ends of the connecting rod, the first support arm and the second support arm are connected through the connecting plates, the end of the second support arm is connected to a core column, and an excitation coil is wound around the core column; each core column is hollow, and a water gap is arranged on the core column. The excitation coils wound around the core columns and the excitation coil on the sleeve are combined to generate different magnetic fields, and the included angles of the core columns can be changed in the horizontal and vertical directions, so that the effect of arc deflection and compression is achieved. An additive manufacturing system comprising the magnetic field generating device and a working method of the additive manufacturing system are also disclosed, the existing magnetic field auxiliary technology is optimized, diversified magnetic field distribution forms are provided, and the effects of refining grains and improving the mechanical properties of formed parts are achieved.

Description

Technical Field

[0001] This invention belongs to the field of metal structural component fused wire / powder feeding additive manufacturing technology, specifically relating to a magnetic field generating device, an additive manufacturing system and its working method. Background Technology

[0002] Currently, traditional CMT welding technology for additive manufacturing of aluminum alloys is prone to defects such as coarse crystal structure, hot cracking, and porosity, resulting in low forming accuracy and poor mechanical properties of the formed parts. Introducing magnetron arc welding technology into the arc wire additive manufacturing process and optimizing the arc wire forming process can enhance the mechanical properties of metal printed parts.

[0003] Existing auxiliary magnetic fields include longitudinal, transverse, horizontal, angular, and rotating magnetic fields. Each auxiliary magnetic field aims to reduce energy loss. Among them, the transverse magnetic field also deflects the arc in the welding direction, suppressing arc tailing. However, current magnetic field technology can only achieve the effect of compressing or deflecting the arc, and different magnetic fields require different magnetic field generating devices, necessitating the design of many different magnetic field generating devices, which is too cumbersome for experimental personnel. Summary of the Invention

[0004] The purpose of this invention is to provide a magnetic field generating device, an additive manufacturing system, and a method for operating the same, which solves the problem that multiple auxiliary magnetic fields require device replacement when changing different magnetic fields due to different generating devices.

[0005] This invention is achieved through the following technical solution:

[0006] This invention discloses a magnetic field generating device, including a sleeve and three magnetic field generating mechanisms connected to the sleeve; the sleeve is located outside the welding torch, and an excitation coil is wound around the lower part of the sleeve;

[0007] Each magnetic field generating mechanism includes a slider and a support arm connected to the slider. The support arm includes a first support arm and a second support arm. The first support arm is hinged to the second support arm and fixedly connected to the slider.

[0008] Slide grooves are prefabricated on the first support arm and the second support arm respectively. Connecting rods are installed in the slide grooves. Connecting plates are connected to both ends of the two connecting rods. The first support arm and the second support arm are connected through the connecting plates. The end of the second support arm is connected to the core column, and an excitation coil is wound on the core column.

[0009] Each core column is hollow inside and has a sprue on it.

[0010] Furthermore, the sleeve is prefabricated with bolt slide rails, and the slider is fixed on the bolt slide rails;

[0011] The bolt guide rail is an annular groove or three intermittent arc grooves.

[0012] Furthermore, the angle between two adjacent arc grooves is 10°-30°, and the corresponding central angle of each arc groove is 90°-110°.

[0013] Furthermore, the sleeve is prefabricated with an annular positioning slide rail, and a positioning block is provided on the inner surface of the slider;

[0014] When the slider is connected to the sleeve, the positioning block is embedded in the positioning slide rail, and the slider rotates around the sleeve along the positioning slide rail.

[0015] Furthermore, the slider is fixed in the bolt rail by bolts, and a baffle is provided on the side where the bolt contacts the welding torch.

[0016] Furthermore, the sleeve has multiple pre-fabricated heat dissipation holes, and the bottom of the sleeve and the free end of the core are connected to an insulating baffle.

[0017] Furthermore, the sleeve is engraved with graduation lines from 0° to 360°, and the top of the slider is equipped with a graduation scale block;

[0018] When the slider is rotated, the scale block aligns with different scale lines, which is used to change the lateral angle between the core pillars.

[0019] The present invention also discloses a method for operating the magnetic field generating device, comprising the following steps:

[0020] Rotate the slider to change the lateral angle between the core pillars;

[0021] The sliding connecting rod changes the angle between the first support arm and the second support arm, thereby changing the longitudinal angle of the core column.

[0022] When the excitation coil on the sleeve is energized, a longitudinal magnetic field is formed;

[0023] Meanwhile, depending on the requirements, different numbers of excitation coils in the magnetic field generating mechanism can be energized to couple with the longitudinal magnetic field to form a variety of different magnetic field distributions, affecting the compression effect on the arc column region; and cooling medium is introduced into the energized core column.

[0024] Furthermore, depending on the requirements, different numbers of excitation coils in the magnetic field generating mechanism are energized, specifically as follows:

[0025] When only one of the magnetic field generating mechanisms is energized, making the magnetic pole at the end of the core column the same as the magnetic pole at the end of the sleeve, the generated magnetic field compresses the arc cross section into a near-elliptical shape and also deflects the arc away from the core column.

[0026] When the excitation coils in the two magnetic field generating mechanisms are energized, the positions of the slider and the support arm are adjusted so that the two energized excitation coils form a 180° angle, and the magnetic poles near the ends of the two excitation coils are the same, which is opposite to the magnetic poles near the ends of the coil on the sleeve. At this time, the magnetic field formed compresses the arc cross section into an ellipse.

[0027] When all three excitation coils in the magnetic field generating mechanism are energized, the position of the slider and the support arm is adjusted so that two adjacent energized excitation coils form a 120° angle. Current is passed through the excitation coils on the three support arms and the excitation coil on the sleeve, so that the magnetic poles at the ends of the excitation coils on the three support arms are the same and opposite to the magnetic poles at the ends of the excitation coil on the sleeve. When the current passing through the three excitation coils on the core column is the same, the spatial magnetic field formed at this time compresses the arc into a near-circular shape, and the compression effect is better than that of a single longitudinal magnetic field. Increasing the current passing through the excitation coil on one of the core columns compresses the arc cross-section into a near-elliptical shape and also causes the arc to deflect towards the excitation coil with the increased current, thus combining the effects of a transverse magnetic field and a sharp-angle magnetic field.

[0028] The present invention also discloses an additive manufacturing system, including a worktable, a substrate, a laser source, a magnetic field control system, a camera, a host computer, and the magnetic field generating device;

[0029] The magnetic field control system includes an adjustable DC regulated excitation power supply and an AC excitation power supply. The excitation coil on the sleeve is connected to the adjustable DC regulated excitation power supply, and the excitation coil on the core column is connected to the AC excitation power supply.

[0030] The substrate is placed on the worktable, and a camera is set on one side of the substrate to align with the deposited part;

[0031] The camera is connected to the host computer; the magnetic field generator is installed on the welding torch head;

[0032] The laser source is emitted towards the deposition object.

[0033] Compared with the prior art, the present invention has the following beneficial technical effects:

[0034] This invention discloses a magnetic field generating device, comprising a sleeve and three magnetic field generating mechanisms connected to the sleeve. An excitation coil is wound around the lower part of the sleeve; when current is passed through it, a longitudinal magnetic field is formed. Each magnetic field generating mechanism includes a slider and support arms. The support arms include a first support arm and a second support arm, with a core column connected to the end of the second support arm. An excitation coil is wound around the core column. The two support arms are hinged, and each support arm has a pre-fabricated groove. A connecting rod is installed in the groove, and the connecting rod is connected by a connecting plate, allowing the two support arms to rotate within a limited range. When the slider is rotated, the lateral angle between the core columns can be changed. Sliding the connecting rod changes its position in the groove, altering the angle between the two support arms, thereby changing the longitudinal angle of the core column. This ensures flexible achievement of different magnetic field distributions during operation, improving the compression effect on the arc column region. The magnetic field generating device designed in this invention can generate various magnetic fields, including longitudinal, lateral, horizontal, and coupled magnetic fields.

[0035] Furthermore, a positioning slide rail is provided on the sleeve, which cooperates with the positioning block on the inner surface of the slider to accurately locate the slider position and fix it in the longitudinal direction.

[0036] Furthermore, a scale block is provided at the top of the slider, and the sleeve is engraved with graduation lines from 0° to 360°. When the slider is rotated, the scale block aligns with different graduation lines, making it easy to clearly change the lateral angle between the core columns. Furthermore, heat-insulating baffles are provided at the ends of each core column to clamp the excitation coil while preventing damage to the excitation coil from the high temperature of the electric arc.

[0037] Furthermore, a cooling channel is set inside the core column to solve the problem of overheating during operation of existing magnetic arc magnetic field generators. This prevents the high temperature generated by the arc from reducing the resistance of the excitation coil, providing a stable magnetic field, and also cools the air around the formed workpiece, thereby accelerating the convective heat transfer between the air and the formed workpiece and cooling it down.

[0038] Furthermore, the sleeve on the welding torch has heat dissipation holes. During welding, because the temperature of the weld pool is extremely high and the temperature of the tail of the welding torch is low, a self-circulating airflow can be generated to achieve the purpose of heat dissipation.

[0039] This invention also discloses a method for operating a magnetic field generating device. Different numbers of excitation coils in the magnetic field generating mechanism can be energized according to requirements, enabling coupling with the longitudinal magnetic field to form various different magnetic field distributions, affecting the compression effect on the arc column region. Specifically, these can be categorized into the following basic cases:

[0040] Install the first slider and support arm, and pass current through the excitation coil on the support arm and the excitation coil on the sleeve so that the magnetic poles generated at the end are the same as the magnetic poles at the end of the sleeve. The magnetic field generated thereby compresses the arc cross section into a near-elliptical shape and also causes the arc to deflect slightly to one side.

[0041] Install the second slider and support arm, rotate the slider and support arm so that they form a 180° angle with the first slider and support arm that have already been installed, and pass current through the excitation coils on the two support arms so that the magnetic poles at the ends of the excitation coils on the two support arms are opposite, thus forming a transverse magnetic field or a horizontal magnetic field; pass current through the excitation coil on the sleeve so that the magnetic poles at the ends of the excitation coils on the two support arms are the same and opposite to the magnetic poles at the ends of the excitation coil on the sleeve. The magnetic field formed at this time compresses the arc cross section into a standard ellipse, which is significantly better than the compression of the arc by a sharp-angled magnetic field.

[0042] Install the third slider and support arm. Rotate the sliders so that the three sliders form a 120° angle with the support arm. Current is supplied to the excitation coils on the three support arms and the sleeve, ensuring that the magnetic poles at the ends of the excitation coils on the three support arms are the same and opposite to those at the ends of the excitation coil on the sleeve. When the current supplied to the three excitation coils on the core column is the same, the resulting spatial magnetic field compresses the arc into a near-circular shape, with a significantly better compression effect than a single longitudinal magnetic field. Increasing the current supplied to the excitation coil on one of the core columns compresses the arc cross-section into a near-elliptical shape and also deflects the arc towards that excitation coil, combining the effects of a transverse magnetic field and a sharp-angle magnetic field. Attached Figure Description

[0043] Figure 1 This is a functional structure diagram of an additive manufacturing system for a magnetic field generating device according to the present invention;

[0044] Figure 2a This is a schematic diagram of the structure of a magnetic field generating device according to Embodiment 1 of the present invention;

[0045] Figure 2b This is an arc morphology diagram of a magnetic field generating device according to Embodiment 1 of the present invention;

[0046] Figure 3a This is a schematic diagram of the structure of a magnetic field generating device according to Embodiment 2 of the present invention;

[0047] Figure 3b This is an arc morphology diagram of a magnetic field generating device according to Embodiment 2 of the present invention;

[0048] Figure 4a This is a schematic diagram of the structure of a magnetic field generating device according to Embodiment 3 of the present invention;

[0049] Figure 4bThis is an arc morphology diagram of a magnetic field generating device according to Embodiment 3 of the present invention;

[0050] Figure 5 This is a schematic diagram of the structure of a magnetic field generating device according to Embodiment 4 of the present invention;

[0051] Figure 6a This is an arc morphology diagram of a magnetic field generating device according to Embodiment 4 of the present invention;

[0052] Figure 6b This is an arc morphology diagram of a magnetic field generating device according to Embodiment 4 of the present invention;

[0053] Figure 7a This is a magnetic field distribution diagram of the magnetic field generating device described in Embodiment 4 of the present invention when the core column axis is tilted upward and the longitudinal angle with the sleeve axis is at its maximum.

[0054] Figure 7b This is an image of the arc shape of the core column of the magnetic field generating device described in Embodiment 4 of the present invention when the axis of the core column is tilted upward and the longitudinal angle with the axis of the sleeve is at its maximum.

[0055] Figure 8a This is a magnetic field distribution diagram of a magnetic field generating device according to Embodiment 4 of the present invention, where the core column axis is tilted downwards and the longitudinal angle between it and the sleeve axis is the smallest.

[0056] Figure 8b This is an image of the arc shape of the core column of the magnetic field generating device described in Embodiment 4 of the present invention, where the axis of the core column is tilted downwards and the longitudinal angle between the core column and the sleeve axis is the smallest.

[0057] Figure 9 This is a schematic diagram of the slider's structure;

[0058] Figure 10 This is a schematic diagram showing the distribution of the arc grooves on the sleeve.

[0059] Among them, 1. Sleeve; 2. Bolt slide rail; 3. Positioning slide rail; 4. Heat dissipation hole; 5. Connecting rod; 6. Connecting plate; 7. Water inlet; 8. Insulating baffle; 9. Core column; 10. Hinge bolt; 11. Nut; 12-1. First slide groove; 12-2. Second slide groove; 13-1. First support arm; 13-2. Second support arm; 14. Slider; 15. Bolt; 16. Baffle; 17. Scale block; 18. Welding torch; 19. Positioning block; 20. Excitation coil; 21. Arc groove. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0061] The components described and illustrated in the accompanying drawings and embodiments of this invention can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely to illustrate one selected embodiment of the invention. All other embodiments obtained by those skilled in the art based on the accompanying drawings and embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0062] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, element, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to the process, element, method, article, or apparatus.

[0063] like Figure 5 As shown, the present invention discloses a magnetic field generating device, including a sleeve 1 and three magnetic field generating mechanisms connected to the sleeve 1; the sleeve 1 is located outside the welding torch 18, and an excitation coil 20 is wound around the lower part of the sleeve 1;

[0064] Each magnetic field generating mechanism includes a slider 14 and a support arm connected to the slider 14. The support arm includes a first support arm 13-1 and a second support arm 13-2. The first support arm 13-1 is hinged to the second support arm 13-2 and the first support arm 13-1 is fixedly connected to the slider 14.

[0065] A first slide groove 12-1 is prefabricated on the first support arm 13-1, and a second slide groove 12-2 is prefabricated on the second support arm. Connecting rods 5 are installed in the first slide groove 12-1 and the second slide groove 12-2. Connecting plates 6 are connected to both ends of the two connecting rods 5. The first support arm 13-1 and the second support arm 13-2 are connected through the connecting plates 6. The end of the second support arm 13-2 is connected to the core column 9, and an excitation coil 20 is wound on the core column 9.

[0066] Each core column 9 is hollow inside, and the core column 9 is provided with a water inlet 7, which includes a water inlet and a water outlet.

[0067] Specifically, 13-1 is hinged to the second support arm 13-2 by hinge bolts 10, and nuts 11 are installed at both ends of the connecting rod 5.

[0068] More preferably, the sleeve 1 is engraved with graduation lines from 0° to 360°, such as... Figure 9 As shown, the top of the slider 14 is provided with a scale block 17; when the slider 14 is rotated, the scale block 17 is aligned with different scale lines, which makes it easy to clearly change the lateral angle between the core columns 9.

[0069] like Figure 2a As shown, a bolt slide rail 2 is prefabricated on the sleeve 1, and the slider 14 is fixed on the bolt slide rail 2.

[0070] Specifically, the bolt slide rail 2 has an annular groove to facilitate the sliding connection of the slider 14.

[0071] Specifically, the bolt guide rail 2 can also be designed as three discontinuous arc grooves 21. See [reference needed] Figure 10 The angle between two adjacent arc grooves 21 is 10°-30°, and the corresponding central angle of each arc groove 21 is 90°-110°, which can ensure that multiple magnetic field distributions with multiple angles are formed between the core columns.

[0072] More preferably, the sleeve 1 is also prefabricated with an annular positioning slide rail 3, which serves to determine the position of the slider 14 and the support arm and prevent it from wobbling left and right. Figure 9 As shown, a positioning block 19 is provided on the inner surface of the slider 14; when the slider 14 is connected to the sleeve 1, the positioning block 19 is embedded in the positioning slide rail 3, and the slider 14 rotates around the sleeve 1 along the positioning slide rail 3.

[0073] The slider 14 is fixed in the bolt slide rail 2 by bolts 15, and a baffle 16 is provided on the side of the bolt 15 that contacts the welding torch 18 to prevent damage to the welding torch 18 when tightening the bolts.

[0074] More preferably, multiple heat dissipation holes 4 are pre-formed on the sleeve 1, and an insulating baffle 8 is connected to the bottom of the sleeve 1 and the free end of the core column 9. This clamps the excitation coil 20 while preventing the high temperature of the electric arc from damaging the excitation coil 20.

[0075] like Figure 1 As shown, the present invention discloses an additive manufacturing system, including a worktable, a substrate, a laser source, a magnetic field control system, a camera, a host computer, and a magnetic field generating device;

[0076] The magnetic field control system includes an adjustable DC regulated excitation power supply and an AC excitation power supply. The excitation coil 20 on the sleeve 1 is connected to the adjustable DC regulated excitation power supply, and the excitation coil 20 on the core column 9 is connected to the AC excitation power supply.

[0077] The substrate is placed on the worktable, and a camera is set on one side of the substrate to align with the deposited part;

[0078] The camera is connected to the host computer; the sharp-angle and longitudinal coupled magnetic field generator is installed on the welding gun head;

[0079] The laser source is emitted towards the deposition object.

[0080] Different numbers of excitation coils 20 in the magnetic field generating mechanism can be energized according to requirements, which can couple with the longitudinal magnetic field to form various different magnetic field distributions, affecting the compression effect on the arc column region. The features and performance of the present invention are further described in detail below with reference to embodiments.

[0081] Example 1

[0082] See Figure 2a When only the excitation coil 20 on sleeve 1 is energized, a longitudinal magnetic field is generated, as shown in the figure. Figure 2b .

[0083] Example 2

[0084] When only the excitation coil 20 in one of the magnetic field generating mechanisms is energized, see Figure 3a Specifically:

[0085] Current is supplied to the excitation coil 20 on sleeve 1 and the excitation coil 20 on the support arm core column 9. The resulting magnetic field compresses the arc cross-section into a near-elliptical shape and deflects the arc away from the core column 9. See Figure 3b .

[0086] Example 3

[0087] When energized, the excitation coils 20 in the two magnetic field generating mechanisms are referred to Figure 4a Specifically:

[0088] Rotate slider 14 so that the two sliders 14 form a 180° angle, and pass current through the excitation coils 20 on the two support arms, so that the magnetic poles at the ends of the excitation coils 20 on the two support arms are opposite, thus forming a transverse magnetic field. Then pass current through the excitation coil 20 on the sleeve 1, so that the magnetic poles at the ends of the excitation coils 20 on the two support arms are the same and opposite to the magnetic poles at the ends of the excitation coils 20 on the sleeve 1. The magnetic field formed at this time compresses the arc cross section into an elliptical shape, and the compression effect on the arc is significantly better than that of a sharp-angled magnetic field, see Figure 4b .

[0089] Example 4

[0090] When all three excitation coils 20 in the magnetic field generating mechanism are energized, see Figure 5 Specifically:

[0091] Rotate slider 14 so that the three sliders 14 form a 120° angle. Current is supplied to the excitation coils 20 on the three support arms and the sleeve 1, making the magnetic poles at the ends of the excitation coils 20 on the three core columns 9 the same and opposite to the magnetic poles at the ends of the excitation coil 20 on the sleeve 1. When the current supplied to the three excitation coils 20 on the core column 9 is the same, the resulting spatial magnetic field compresses the arc into a near-circular shape, and the compression effect is significantly better than that of a single longitudinal magnetic field. (See...) Figure 6a Increasing the current flowing through the excitation coil 20 on one of the support arms compresses the arc cross-section into a near-elliptical shape while simultaneously deflecting the arc towards the excitation coil 20, thus combining the effects of a transverse magnetic field and a sharp-angle magnetic field. (See...) Figure 6b .

[0092] Example 5

[0093] Based on Example 4, the sliding connecting rod 5 changes the angle between the first support arm 13-1 and the second support arm 13-2, thus changing the longitudinal angle of the core column 9 and causing the axis of the core column 9 to tilt upwards. At this time, the spatial magnetic field strength outside the arc increases, and the magnetic induction lines become approximately tangent to the outer surface of the arc, improving the compression effect on the arc. For the effect of the magnetic field on the arc, please refer to [link to relevant documentation]. Figure 7a and Figure 7b .

[0094] Example 6

[0095] Based on Example 4, the sliding connecting rod 5 changes the angle between the first support arm 13-1 and the second support arm 13-2, thus changing the longitudinal angle of the core column 9. This causes the axis of the core column 9 to tilt downwards. At this time, the intensity of the spatial magnetic field outside the arc decreases, and the magnetic induction lines are mostly at an angle to the outer surface of the arc, reducing the compression effect on the arc. For the effect of the magnetic field on the arc, please refer to [link to relevant documentation]. Figure 8a and Figure 8b .

[0096] like Figure 1 As shown, this invention discloses a method for operating an additive manufacturing system, comprising the following steps:

[0097] S1, welding torch 18, and the worktable are connected to the positive and negative terminals of the welding power supply, respectively. The substrate is placed on the worktable and fixed. Set the additive manufacturing process parameters, including wire feed speed, welding speed, welding mode, shielding gas flow rate, etc. The wire extension should be between 12 and 20 mm.

[0098] S2. Install the magnetic field generator on the welding torch 18, install the three sliders 14 and the support arm on the sleeve 1, connect the four excitation coils 20 to the four adjustable DC regulated excitation power supplies respectively, and then connect the cooling water inlet and outlet to the cooling circulation system through hoses.

[0099] S3. When printing with the welding torch, turn on the cooling circulation system, excitation power supply and laser source, and observe the arc morphology, droplet transfer and molten pool flow in real time on the host computer through a high-speed camera; the cooling system continuously dissipates heat and cools the excitation device to reduce the impact of temperature on magnetic field strength and stability.

[0100] S4. Turn on the power supply connected to the excitation coil 20 on sleeve 1 only to obtain a longitudinal magnetic field; turn on the power supply connected to the excitation coil 20 on sleeve 1 and the excitation coil 20 on one support arm, so that the magnetic pole at the end of the core 9 is the same as the magnetic pole at the end of sleeve 1; rotate slider 14 to adjust the included angle between two of the support arms to 180°, turn on the power supply connected to the excitation coil 20 on these two support arms, so that the magnetic poles at the ends of the excitation coil 20 on the two support arms are opposite, thus forming a transverse magnetic field or a horizontal magnetic field; turn on the power supply connected to the excitation coil 20 on sleeve 1 again, and make the magnetic poles at the ends of the excitation coil 20 on the two support arms the same and opposite to the magnetic poles at the ends of the excitation coil 20 on sleeve 1; rotate slider 14 to adjust the included angle between the three support arms to 120°, and pass current to the excitation coil 20 on the three support arms and the excitation coil 20 on sleeve 1, so that the magnetic poles at the ends of the excitation coil 20 on the three support arms are the same and opposite to the magnetic poles at the ends of the excitation coil 20 on sleeve 1. The different magnetic fields mentioned above can all change the magnitude and frequency of the Lorentz force on the electric arc plasma and the molten metal droplets, thus affecting the arc morphology, droplet transition state, and molten pool state, thereby achieving the effects of refining grains and improving forming quality.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A magnetic field generating device, characterized in that, It includes a sleeve (1) and three magnetic field generating mechanisms connected to the sleeve (1); the sleeve (1) is located outside the welding torch (18), and an excitation coil (20) is wound around the lower part of the sleeve (1). Each magnetic field generating mechanism includes a slider (14) and a support arm connected to the slider (14). The support arm includes a first support arm (13-1) and a second support arm (13-2). The first support arm (13-1) is hinged to the second support arm (13-2), and the first support arm (13-1) is fixedly connected to the slider (14). Slide grooves are prefabricated on the first support arm (13-1) and the second support arm (13-2), and connecting rods (5) are installed in the slide grooves. Connecting plates (6) are connected to both ends of the two connecting rods (5). The first support arm (13-1) and the second support arm (13-2) are connected through the connecting plates (6). The end of the second support arm (13-2) is connected to the core column (9), and an excitation coil (20) is wound on the core column (9). Each core column (9) is hollow inside, and a water inlet (7) is provided on the core column (9); A bolt slide rail (2) is prefabricated on the sleeve (1), and the slider (14) is fixed on the bolt slide rail (2); The bolt slide rail (2) is an annular groove or three intermittent arc grooves (21).

2. A magnetic field generating device according to claim 1, characterized in that The angle between two adjacent arc grooves (21) is 10°-30°, and the corresponding central angle of each arc groove (21) is 90°-110°.

3. A magnetic field generating device according to claim 1, wherein The sleeve (1) is also prefabricated with an annular positioning slide rail (3), and a positioning block (19) is provided on the inner surface of the slider (14). When the slider (14) is connected to the sleeve (1), the positioning block (19) is embedded in the positioning slide rail (3), and the slider (14) rotates around the sleeve (1) along the positioning slide rail (3).

4. A magnetic field generating device according to claim 1, characterized in that, The slider (14) is fixed in the bolt slide rail (2) by bolts (15), and a baffle (16) is provided on the side of the bolt (15) that contacts the welding gun (18).

5. A magnetic field generating device according to claim 1, characterized in that, Multiple heat dissipation holes (4) are pre-made on the sleeve (1), and the bottom of the sleeve (1) and the free end of the core column (9) are connected to the heat insulation baffle (8).

6. A magnetic field generating device according to claim 1, wherein The sleeve (1) is engraved with scale lines from 0° to 360°, and the top of the slider (14) is provided with a scale block (17). When the slider (14) is rotated, the scale block (17) is aligned with different scale lines to change the lateral angle between the cores (9).

7. The method of operating the magnetic field generating device according to any one of claims 1-6, characterized in that, Includes the following processes: Rotate the slider (14) to change the lateral angle between the core pillars (9); Slide the connecting rod (5) to change the angle between the first support arm (13-1) and the second support arm (13-2), thereby changing the longitudinal angle of the core column (9); When the excitation coil (20) on the sleeve (1) is energized, a longitudinal magnetic field is formed; At the same time, depending on the needs, different numbers of excitation coils (20) in the magnetic field generating mechanism are selected for energization, which can couple with the longitudinal magnetic field to form a variety of different magnetic field distributions, affecting the compression effect on the arc column area; and cooling medium is introduced into the energized core column (9).

8. The method of operating the magnetic field generating device according to claim 7, characterized in that, Depending on the requirements, different numbers of excitation coils (20) in the magnetic field generating mechanism are energized, specifically: When only one of the magnetic field generating mechanisms is energized, the magnetic pole at the end of the core column (9) is the same as the magnetic pole at the end of the sleeve (1). The generated magnetic field compresses the arc cross section into a near-elliptical shape and also causes the arc to deflect away from the core column (9). When the excitation coils (20) in the two magnetic field generating mechanisms are energized, the position of the slider (14) and the support arm is adjusted so that the two energized excitation coils (20) form a 180° angle, and the magnetic poles of the two excitation coils (20) near the end are the same, which is opposite to the magnetic poles of the coil near the end on the sleeve (1). At this time, the magnetic field formed compresses the arc cross section into an ellipse. When all three excitation coils (20) in the magnetic field generating mechanism are energized, the position of the slider (14) and the support arm is adjusted so that the two adjacent energized excitation coils (20) form a 120° angle. Current is passed into the excitation coils (20) on the three support arms and the excitation coils (20) on the sleeve (1) so that the magnetic poles at the ends of the excitation coils (20) on the three support arms are the same and opposite to the magnetic poles at the ends of the excitation coils (20) on the sleeve (1). When the current passed into the three excitation coils (20) on the core column (9) is the same, the spatial magnetic field formed at this time will compress the electric arc into a near circle, and the compression effect is better than that of a single longitudinal magnetic field. When the current passed into the excitation coil (20) on one of the core columns (9) is increased, the cross section of the electric arc is compressed into a near ellipse and the electric arc is deflected towards the direction of the excitation coil (20) with the increased current, which has the effect of both a transverse magnetic field and a sharp-angle magnetic field.

9. An additive manufacturing system, characterized by It includes a worktable, a substrate, a laser source, a magnetic field control system, a camera, a host computer, and the magnetic field generating device according to any one of claims 1-6; The magnetic field control system includes an adjustable DC regulated excitation power supply and an AC excitation power supply. The excitation coil (20) on the sleeve (1) is connected to the adjustable DC regulated excitation power supply, and the excitation coil (20) on the core column (9) is connected to the AC excitation power supply. The substrate is placed on the worktable, and a camera is set on one side of the substrate to align with the deposited part; The camera is connected to the host computer; the magnetic field generator is installed on the welding torch head; The laser source is emitted towards the deposition object.

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