A method for producing a metal truss structure using a high-energy beam 3D printing

Abstract

The application provides a method for preparing a metal truss structure by using a high-energy beam 3D printing, which comprises the following steps: S10. The free end of a wire material with a wire diameter of 0.8mm-4mm is pulled to a first target welding point on a base material, a focal point of a laser beam with a power of not more than 2000W is aligned with the first target welding point for spot welding, so that one end of the wire material is welded on the base material, and the exposure time of the laser beam is 0.04s-0.4s; S20. The wire material is pulled towards a second target welding point on the base material, so that the wire material is in contact with the second target welding point on the base material, and the wire material is welded on the base material at the second target welding point in the welding mode of the wire material welded at the first target welding point; and S30. The wire material is cut off by using a single-pulse laser with a duration of 1ms-10ms or a multi-pulse laser with an action time of 10-100 pulse periods and a peak power of 200w-2000w at the second target welding point. The application has the beneficial effects of high production efficiency, low cost, and the combination of the laser beam and the plasma beam used alone or in combination, and is more flexible.

Description

Technical Field

[0001] This invention relates to the field of metal structure fabrication technology, and specifically to a method for fabricating metal truss structures using high-energy beam 3D printing. Background Technology

[0002] 3D printing is a manufacturing technology that has developed rapidly in the last two decades. It can quickly manufacture products such as metals, plastics, and concrete, and is being used more and more widely in industrial production. Common heat sources for 3D printing to prepare metal structures include laser beams, electron beams, and plasma arcs.

[0003] In the laser selective sintering method described in patent number WO2001091924A1, the method involves first uniformly spreading a layer of metal powder on the surface of a substrate, and then selectively melting and sintering the metal powder according to the cross-section of the target structure. This process is repeated layer by layer until a complete three-dimensional target structure is formed. The disadvantages of this method are low production efficiency, as the process requires layer-by-layer powder spreading and melting / sintering. Furthermore, the surface roughness of the structure prepared by this method is highly dependent on the particle size of the powder used, necessitating the use of smaller particle sizes, thus increasing manufacturing costs. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by proposing a method for fabricating metal truss structures using high-energy beam 3D printing, which has high production efficiency and low cost.

[0005] This invention proposes a method for fabricating metal truss structures using high-energy beam 3D printing, the improvement of which includes the following steps:

[0006] S10. The free end of a metal wire with a diameter of 0.8mm to 4mm is drawn to the first target welding point on the substrate. The focal point of a laser beam with a power of no more than 2000W is aligned with the first target welding point for spot welding, so that one end of the wire is welded to the substrate. The exposure time of the laser beam is 0.04s to 0.4s.

[0007] S20. Pull the wire toward the second target weld point on the substrate so that the wire contacts the second target weld point on the substrate, and weld the wire to the substrate at the second target weld point in the same way as welding the wire to the first target weld point;

[0008] S30. At the second target welding point, the wire is cut using a single-pulse laser with a duration of 1ms to 10ms or a multi-pulse laser with a pulse period of 1ms to 1s, an action time of 10 to 100 pulse cycles, and a peak power of 200w to 2000w.

[0009] S40. Repeat steps S10 to S30 to build the metal truss of the required structure on the substrate.

[0010] The preferred technical solution of the present invention is as follows: In steps S10 and S20, after the welding of the first target weld point and the second target weld point is completed, a pressure of 2 kgf to 40 kgf is applied to the wire along the wire axis, and at the same time, a laser beam with a power of 200 W to 2000 W performs a reciprocating scanning motion on the wire around the target weld point along the wire axis. The amplitude of the reciprocating scanning motion is 0.1 mm to 2 mm, and the frequency is 50 Hz to 250 Hz.

[0011] A preferred technical solution of the present invention is as follows: During the reciprocating scanning motion of the laser beam on the filament, a protective gas with a flow rate of 5 L / min to 15 L / min is introduced into the laser action area; the protective gas is argon, helium, carbon dioxide, nitrogen, or a mixture of two or more of the above gases.

[0012] The preferred technical solution of the present invention is that the protective gas is in a laminar flow state in the laser action zone, and the cross-sectional area of ​​the protective gas laminar flow beam is greater than 5 times the maximum size of the laser welding molten pool.

[0013] A preferred technical solution of the present invention is as follows: In step S30, when the laser cuts the wire, a narrow compressed air jet with a pressure of 0.2MPa to 0.6MPa is introduced in a direction perpendicular to the wire.

[0014] The preferred technical solution of this invention is as follows: When it is necessary to build a planar structure on a substrate, the following steps are adopted:

[0015] S100. Multiple wires are welded to the substrate in parallel with each other using the methods in steps S10 to S30, and adjacent wires are in contact with each other.

[0016] S200. A laser beam with a power of 200w to 2000w and a moving speed of 0.5m / min to 5m / min is used to weld the joint between adjacent wires, so that the adjacent wires can be connected along the entire length of the wire.

[0017] S300. Along the axial direction of the wire, with an energy density of 10 5 W / cm² ~ 10 8 A laser beam of W / cm² is used to perform oscillating scanning on the filament. The oscillation frequency of the laser beam is 30Hz to 300Hz, and the amplitude of the laser beam oscillation is at least 2.5 times the diameter of the filament.

[0018] S400. Based on the required dimensions of the planar structure, repeat steps S100 to S300 to complete the welding of single or multiple layers to form the required planar structure.

[0019] A preferred technical solution of the present invention: When the lead screw is made of aluminum, magnesium, beryllium and their alloys, the welding process in steps S100 to S200 can be performed using a combination of laser beam and variable polarity plasma arc welding, wherein the laser beam power is not greater than 2000W, the exposure time is 0.04s to 0.4s, the current pulse frequency of the variable polarity plasma arc is 100Hz to 500Hz, the positive polarity current is 5A to 50A, and the reverse polarity current is 3A to 30A.

[0020] The preferred technical solution of the present invention is as follows: when the lead screw is made of aluminum, magnesium, beryllium and their alloys, the welding process in steps S100 to S200 can be carried out by variable polarity plasma arc welding, the frequency of the variable polarity plasma arc is 100Hz to 500Hz, the positive polarity current does not exceed 100A, and the reverse polarity current does not exceed 50A.

[0021] The preferred technical solution of the present invention is as follows: In step S300, the wire scanning welding can be performed using a combination of laser beam and plasma arc welding, with the power ratio of the laser beam and the plasma arc being 1:1 to 1:3.

[0022] The preferred technical solution of the present invention is as follows: In step S300, the wire scanning welding can be performed using variable polarity plasma arc welding, with an arc power of 200W to 6000W and a positive polarity current of 10A to 150A.

[0023] The beneficial effects of this invention are as follows: This invention uses a high-energy beam as a heat source, utilizing this heat source for cutting and welding of filaments, ultimately achieving the fabrication of a three-dimensional metal truss structure. Because this method uses filaments as raw materials, it has lower costs and higher production efficiency. Furthermore, since the filaments do not need to be completely melted during the structure fabrication process, it rapidly improves production efficiency while significantly reducing heat input during manufacturing, further lowering costs. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In these drawings, similar reference numerals are used to denote similar elements. The drawings described below are some embodiments of the invention, but not all embodiments. Other drawings will be readily available to those skilled in the art based on these drawings without any inventive effort.

[0025] Figure 1 This is a flowchart of a method for fabricating metal truss structures using high-energy beam 3D printing according to the present invention.

[0026] Figure 2 This is a schematic diagram of steps S10 to S30 in the method for preparing a metal truss structure using high-energy beam 3D printing according to the present invention.

[0027] Figure 3 This is a schematic diagram illustrating the effect of constructing a planar structure using a method for fabricating metal truss structures using high-energy beam 3D printing according to the present invention.

[0028] Figure 4 This is a schematic diagram illustrating the effect of leveling a plane on a method for fabricating a metal truss structure using high-energy beam 3D printing, as described in this invention.

[0029] Figure 5 This is a comparison image showing the repair effect of wire edge biting on the method of preparing metal truss structure by high-energy beam 3D printing according to the present invention.

[0030] In the diagram: 1. Wire material; 2. Wire guide nozzle; 3. High-energy beam; 4. First target solder joint; 5. Second target solder joint. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0032] Example 1: Refer to Figure 1 and Figure 2 As shown in the figure, this embodiment provides a method for fabricating metal truss structures using high-energy beam 3D printing, including the following steps:

[0033] S10. The free end of the metal wire 1 with a diameter of 0.8 mm is pulled to the first target welding point 4 on the substrate through the wire guide nozzle 2. The focus of the laser beam 3 with a power of 1200W is aligned with the first target welding point 4 for spot welding, so that one end of the wire 1 is welded to the substrate. The exposure time of the laser beam 3 is 0.04s.

[0034] S20. Pull the wire toward the second target weld point 5 on the substrate so that the wire 1 contacts the second target weld point 5 on the substrate, and weld the wire 1 to the substrate at the second target weld point 5 in the same way as welding the wire 1 to the first target weld point 4.

[0035] S30. At the second target welding point, the wire is cut using a single-pulse laser with a duration of 1 ms or a multi-pulse laser with a pulse period of 1 ms, an action time of 10 pulse cycles, and a peak power of 200 W. When the laser cuts the wire, a narrow compressed air jet with a pressure of 0.2 MPa is introduced in a direction perpendicular to the wire, which is beneficial to the smooth cutting of the wire by the laser.

[0036] S40. Repeat steps S10 to S30 to build the metal truss of the required structure on the substrate.

[0037] The method provided by this invention guides the free end of a wire (the free end being the end of the wire extending from the guide nozzle) to a first target welding point. After welding, the wire is guided to a second target welding point for welding and then cut, forming a wire with both ends welded to a substrate. Through this wire welding and cutting process, a wire-frame truss structure can be manufactured. Then, by layering these structures in the same manner, prisms, cubes, parallelepipeds, icosahedrons, and other similar structures can be formed. To obtain structures with different properties, the wires used can be of the same material or different materials.

[0038] Compared to the layer-by-layer sintering of metal powders, it has the following advantages:

[0039] I. The production of metal truss structures is highly efficient, with a high product qualification rate and virtually no defective products.

[0040] Second, it has a wide range of applicable materials. It can be used to prepare metal structures made of carbon steel, stainless steel and other materials, as well as metal structures made of aluminum, magnesium, beryllium and other easily oxidized metals and alloys.

[0041] Third, low manufacturing cost. Because it uses wire, and the wire does not need to be completely melted, energy consumption is reduced, thus lowering production costs.

[0042] Fourth, 3D printing of truss structures can be achieved without a vacuum environment, saving the time of vacuuming, and the size of the target product is not limited by the size of the vacuum chamber.

[0043] Fifth, the heat input of the target product is greatly reduced, thus reducing energy costs.

[0044] VI. High material utilization rate: There is almost no filament loss during the 3D printing process.

[0045] Furthermore, to eliminate the defect of wire undercut at the target weld point, in steps S10 and S20, after the welding of the first and second target weld points is completed, a pressure of 2 kgf is applied to the wire along the wire axis. Simultaneously, a 200 W laser beam reciprocates along the wire axis around the target weld point, with an amplitude of 0.1 mm and a frequency of 50 Hz. During the reciprocating motion of the laser beam on the wire, a protective gas with a flow rate of 5 L / min is introduced into the laser-affected area; the protective gas is a mixture of helium, carbon dioxide, and nitrogen. The protective gas is in a laminar flow state in the laser-affected area, and the cross-sectional area of ​​the laminar flow beam is greater than 5 times the maximum size of the laser-welded molten pool.

[0046] Reference Figure 5 As shown, Figure 5 (a) is a photograph of a wire with undercut defects after welding at the target weld point. Figure 5 (b) is a diagram showing the effect of repairing the edge bite of the wire using this method.

[0047] When it is necessary to build a planar structure on a substrate, such as a three-dimensional structure that requires a continuous surface shell or a continuous surface inside as a partition or reinforcing rib, the following steps are used:

[0048] S100. Multiple wires are welded to the substrate in parallel with each other using the methods described in steps S10 to S30, with adjacent wires in contact with each other.

[0049] S200. A laser beam with a power of 200W and a moving speed of 0.5m / min is used to weld the joints between adjacent wires, achieving a connection of the entire length of the adjacent wires. (Refer to...) Figure 3 As shown, Figure 3 (a) and Figure 3 (b) shows a schematic diagram and a partial schematic diagram of the structure with wires welded side by side parallel to the substrate. The planar structure can be constructed by welding the wires side by side parallel to the substrate.

[0050] S300. Along the axial direction of the wire, with an energy density of 10 5 A laser beam of W / cm² is used to perform a oscillating scan on the filament. The laser beam oscillates at a frequency of 30Hz, and the amplitude of the oscillation is 2.5 times the diameter of the filament. (Refer to...) Figure 4 As shown, Figure 4 (a) and Figure 4 (b) are schematic diagrams and partial schematic diagrams showing the effect after this step. After the wire is assembled and welded, the wire is oscillating and scanning to form an outer surface or partition with a thickness not less than the radius of the wire. The surface is flat, eliminating the concavity between the wires caused by the shape of the wire.

[0051] S400. Based on the required dimensions of the planar structure, repeat steps S100 to S300 to complete the welding of single or multiple layers to form the required planar structure.

[0052] When the lead screw is made of aluminum, magnesium, beryllium, or other easily oxidized metals or their alloys, the welding process in steps S100 to S200 can employ a combination of laser beam and variable polarity plasma arc welding, wherein the laser beam power is 1200W, the exposure time is 0.04s, the current pulse frequency of the variable polarity plasma arc is 100Hz, the positive polarity current is 5A, and the reverse polarity current is 3A.

[0053] When the lead screw is made of aluminum, magnesium, beryllium or other easily oxidized metals or their alloys, the welding process in steps S100 to S200 can be performed using variable polarity plasma arc welding. The frequency of the variable polarity plasma arc is 100Hz, the positive polarity current does not exceed 60A, and the reverse polarity current does not exceed 30A.

[0054] In step S300, the wire scanning welding can be performed using a combination of laser beam and plasma arc welding, with the power ratio of the laser beam to the plasma arc being 1:1.

[0055] In step S300, the wire scanning welding can be performed using variable polarity plasma arc welding, with an arc power of 200W and a positive polarity current of 10A.

[0056] Example 2: Refer to Figure 1 and Figure 2 As shown in the figure, this embodiment provides a method for fabricating metal truss structures using high-energy beam 3D printing, including the following steps:

[0057] S10. The free end of the metal wire 1 with a diameter of 1.5mm is pulled to the first target welding point 4 on the substrate through the wire guide nozzle 2. The focus of the laser beam 3 with a power of 1400W is aligned with the first target welding point 4 for spot welding, so that one end of the wire 1 is welded to the substrate. The exposure time of the laser beam 3 is 0.1s.

[0058] S20. Pull the wire 1 toward the second target weld point 5 on the substrate so that the wire 1 contacts the second target weld point 5 on the substrate, and weld the wire 1 to the substrate at the second target weld point 5 in the manner of welding the wire to the first target weld point 4.

[0059] S30. At the second target welding point, the wire is cut using a single-pulse laser with a duration of 3ms or a multi-pulse laser with a pulse period of 300ms, an action time of 30 pulse cycles, and a peak power of 800W. When the laser cuts the wire, a narrow compressed air jet with a pressure of 0.3MPa is introduced in a direction perpendicular to the wire, which is beneficial to the smooth cutting of the wire by the laser.

[0060] S40. Repeat steps S10 to S30 to build the metal truss of the required structure on the substrate.

[0061] The method provided by this invention guides the free end of a wire (the free end being the end of the wire extending from the guide nozzle) to a first target welding point. After welding, the wire is guided to a second target welding point for welding and then cut, forming a wire with both ends welded to a substrate. Through this wire welding and cutting process, a wire-frame truss structure can be manufactured. Then, by layering these structures in the same manner, prisms, cubes, parallelepipeds, icosahedrons, and other similar structures can be formed. To obtain structures with different properties, the wires used can be of the same material or different materials.

[0062] Compared to the layer-by-layer sintering of metal powders, it has the following advantages:

[0063] VII. The production of metal truss structures is highly efficient, with a high product qualification rate and virtually no defective products.

[0064] 8. It has a wide range of applicable materials. It can be used to prepare metal structures not only made of carbon steel and stainless steel, but also of aluminum, magnesium, beryllium and other easily oxidized metals and alloys.

[0065] 9. Low manufacturing cost. Because it uses wire, and the wire does not need to be completely melted, energy consumption is reduced, thus lowering production costs.

[0066] 10. 3D printing of truss structures can be achieved without a vacuum environment, saving vacuuming time, and the size of the target product is not limited by the size of the vacuum chamber.

[0067] 11. The heat input of the target product is greatly reduced, thus reducing energy costs.

[0068] 12. High material utilization rate: There is almost no filament loss during the 3D printing process.

[0069] Furthermore, to eliminate the defect of wire undercut at the target weld point, in steps S10 and S20, after the welding of the first and second target weld points is completed, a pressure of 10 kgf is applied to the wire along the wire axis. Simultaneously, a laser beam with a power of 800 W reciprocates along the wire axis around the target weld point, with an amplitude of 0.5 mm and a frequency of 100 Hz. During the reciprocating motion of the laser beam on the wire, a protective gas with a flow rate of 8 L / min is introduced into the laser-affected area; the protective gas is a mixture of argon and helium. The protective gas is in a laminar flow state in the laser-affected area, and the cross-sectional area of ​​the laminar flow beam is greater than 5 times the maximum size of the laser-welded molten pool.

[0070] Reference Figure 5 As shown, Figure 5 (a) is a photograph of a wire with undercut defects after welding at the target weld point. Figure 5 (b) is a diagram showing the effect of repairing the edge bite of the wire using this method.

[0071] When it is necessary to build a planar structure on a substrate, such as a three-dimensional structure that requires a continuous surface shell or a continuous surface inside as a partition or reinforcing rib, the following steps are used:

[0072] S100. Multiple wires are welded to the substrate in parallel with each other using the methods described in steps S10 to S30, with adjacent wires in contact with each other.

[0073] S200. A laser beam with a power of 800W and a moving speed of 1.5m / min is used to weld the joints between adjacent wires, achieving a connection of the entire length of the adjacent wires. (Refer to...) Figure 3 As shown, Figure 3 (a) and Figure 3 (b) shows a schematic diagram and a partial schematic diagram of the structure with wires welded side by side parallel to the substrate. The planar structure can be constructed by welding the wires side by side parallel to the substrate.

[0074] S300. Along the axial direction of the wire, with an energy density of 10 6 A laser beam of W / cm² is used to perform oscillating scanning on the filament. The laser beam oscillates at a frequency of 100Hz, and the amplitude of the oscillation is 2.8 times the diameter of the filament. (Refer to...) Figure 4 As shown, Figure 4 (a) and Figure 4 (b) are schematic diagrams and partial schematic diagrams showing the effect after this step. After the wire is assembled and welded, the wire is oscillating and scanning to form an outer surface or partition with a thickness not less than the radius of the wire. The surface is flat, eliminating the concavity between the wires caused by the shape of the wire.

[0075] S400. Based on the required dimensions of the planar structure, repeat steps S100 to S300 to complete the welding of single or multiple layers to form the required planar structure.

[0076] When the lead screw is made of aluminum, magnesium, beryllium, or other easily oxidized metals or their alloys, the welding process in steps S100 to S200 can employ a combination of laser beam and variable polarity plasma arc welding, wherein the laser beam power is 1400W, the exposure time is 0.1s, the current pulse frequency of the variable polarity plasma arc is 200Hz, the positive polarity current is 10A, and the reverse polarity current is 8A.

[0077] When the lead screw is made of aluminum, magnesium, beryllium or other easily oxidized metals or their alloys, the welding process in steps S100 to S200 can be performed using variable polarity plasma arc welding. The frequency of the variable polarity plasma arc is 200Hz, the positive polarity current is 80A, and the reverse polarity current is 40A.

[0078] In step S300, the wire scanning welding can be performed using a combination of laser beam and plasma arc welding, with the power ratio of the laser beam to the plasma arc being 1:2.

[0079] In step S300, the wire scanning welding can be performed using variable polarity plasma arc welding, with an arc power of 1500W and a positive polarity current of 30A.

[0080] Example 3: Refer to Figure 1 and Figure 2 As shown in the figure, this embodiment provides a method for fabricating metal truss structures using high-energy beam 3D printing, including the following steps:

[0081] S10. The free end of the metal wire 1 with a diameter of 2.5mm is pulled to the first target welding point 4 on the substrate through the wire guide nozzle 2. The focus of the laser beam 3 with a power of 1600W is aligned with the first target welding point 4 for spot welding, so that one end of the wire 1 is welded to the substrate. The exposure time of the laser beam 3 is 0.2s.

[0082] S20. Pull the wire 1 toward the second target weld point 5 on the substrate so that the wire 1 contacts the second target weld point 5 on the substrate, and weld the wire 1 to the substrate at the second target weld point 5 in the same way as welding the wire 1 to the first target weld point 4.

[0083] S30. At the second target welding point, the wire is cut using a single-pulse laser with a duration of 5ms or a multi-pulse laser with a pulse period of 500ms, an action time of 50 pulse cycles, and a peak power of 1500W. When the laser cuts the wire, a narrow compressed air jet with a pressure of 0.4MPa is introduced in a direction perpendicular to the wire, which is beneficial to the smooth cutting of the wire by the laser.

[0084] S40. Repeat steps S10 to S30 to build the metal truss of the required structure on the substrate.

[0085] The method provided by this invention guides the free end of a wire (the free end being the end of the wire extending from the guide nozzle) to a first target welding point. After welding, the wire is guided to a second target welding point for welding and then cut, forming a wire with both ends welded to a substrate. Through this wire welding and cutting process, a wire-frame truss structure can be manufactured. Then, by layering these structures in the same manner, prisms, cubes, parallelepipeds, icosahedrons, and other similar structures can be formed. To obtain structures with different properties, the wires used can be of the same material or different materials.

[0086] Compared to the layer-by-layer sintering of metal powders, it has the following advantages:

[0087] Thirteen, the production of metal truss structures is highly efficient, with a high product qualification rate and almost no defective products.

[0088] Fourteen, it has a wide range of applicable materials. It can be used to prepare metal structures made of carbon steel, stainless steel and other materials, as well as metal structures made of aluminum, magnesium, beryllium and other easily oxidized metals and alloys.

[0089] 15. Low manufacturing cost. Because it uses wire, and the wire does not need to be completely melted, energy consumption is reduced, thus lowering production costs.

[0090] Sixteen, 3D printing of truss structures can be achieved without a vacuum environment, saving vacuuming time, and the size of the target product is not limited by the size of the vacuum chamber.

[0091] 17. The heat input of the target product is greatly reduced, thus reducing energy consumption costs.

[0092] 18. High material utilization rate: There is almost no filament loss during the 3D printing process.

[0093] Furthermore, to eliminate the defect of wire undercut at the target weld point, in steps S10 and S20, after the welding of the first and second target weld points is completed, a pressure of 20 kgf is applied to the wire along the wire axis. Simultaneously, a 1500 W laser beam reciprocates along the wire axis around the target weld point, with an amplitude of 1 mm and a frequency of 150 Hz. During the reciprocating motion of the laser beam on the wire, a protective gas with a flow rate of 10 L / min is introduced into the laser-affected zone; the protective gas is a mixture of carbon dioxide and nitrogen. The protective gas is in a laminar flow state in the laser-affected zone, and the cross-sectional area of ​​the laminar flow beam is greater than 5 times the maximum size of the laser-welded molten pool.

[0094] Reference Figure 5 As shown, Figure 5 (a) is a photograph of a wire with undercut defects after welding at the target weld point. Figure 5 (b) is a diagram showing the effect of repairing the edge bite of the wire using this method.

[0095] When it is necessary to build a planar structure on a substrate, such as a three-dimensional structure that requires a continuous surface shell or a continuous surface inside as a partition or reinforcing rib, the following steps are used:

[0096] S100. Multiple wires are welded to the substrate in parallel with each other using the methods described in steps S10 to S30, with adjacent wires in contact with each other.

[0097] S200. A laser beam with a power of 1500W and a moving speed of 3m / min is used to weld the joints between adjacent wires, achieving a connection of the entire length of the adjacent wires. (Refer to...) Figure 3 As shown, Figure 3 (a) and Figure 3 (b) shows a schematic diagram and a partial schematic diagram of the structure with wires welded side by side parallel to the substrate. The planar structure can be constructed by welding the wires side by side parallel to the substrate.

[0098] S300. Along the axial direction of the wire, with an energy density of 10 7 A laser beam of W / cm² is used to perform a oscillating scan on the filament. The laser beam oscillates at a frequency of 200Hz, and the amplitude of the oscillation is three times the diameter of the filament. (Refer to...) Figure 4 As shown, Figure 4 (a) and Figure 4 (b) are schematic diagrams and partial schematic diagrams showing the effect after this step. After the wire is assembled and welded, the wire is oscillating and scanning to form an outer surface or partition with a thickness not less than the radius of the wire. The surface is flat, eliminating the concavity between the wires caused by the shape of the wire.

[0099] S400. Based on the required dimensions of the planar structure, repeat steps S100 to S300 to complete the welding of single or multiple layers to form the required planar structure.

[0100] When the lead screw is made of aluminum, magnesium, beryllium, or other easily oxidized metals or their alloys, the welding process in steps S100 to S200 can employ a combination of laser beam and variable polarity plasma arc welding, wherein the laser beam power is 1600W, the exposure time is 0.2s, the current pulse frequency of the variable polarity plasma arc is 350Hz, the positive polarity current is 25A, and the reverse polarity current is 15A.

[0101] When the lead screw is made of aluminum, magnesium, beryllium or other easily oxidized metals or their alloys, the welding process in steps S100 to S200 can be performed using variable polarity plasma arc welding. The frequency of the variable polarity plasma arc is 200Hz, the positive polarity current is 80A, and the reverse polarity current is 40A.

[0102] In step S300, the wire scanning welding can be performed using a combination of laser beam and plasma arc welding, with the power ratio of the laser beam to the plasma arc being 1:2.

[0103] In step S300, the wire scanning welding can be performed using variable polarity plasma arc welding, with an arc power of 1500W and a positive polarity current of 30A.

[0104] Example 4: Refer to Figure 1 and Figure 2 As shown in the figure, this embodiment provides a method for fabricating metal truss structures using high-energy beam 3D printing, including the following steps:

[0105] S10. The free end of the metal wire 1 with a diameter of 4mm is pulled to the first target welding point 4 on the substrate through the wire guide nozzle 2. The focus of the laser beam 3 with a power of 2000W is aligned with the first target welding point 4 for spot welding, so that one end of the wire 1 is welded to the substrate. The exposure time of the laser beam 3 is 0.4s.

[0106] S20. Pull the wire 1 toward the second target weld point 4 on the substrate so that the wire 1 contacts the second target weld point 5 on the substrate, and weld the wire 1 to the substrate at the second target weld point 5 in the same way as welding the wire 1 to the first target weld point 4.

[0107] S30. At the second target welding point, the wire is cut using a single-pulse laser with a duration of 10ms or a multi-pulse laser with a pulse period of 1s, an action time of 100 pulse cycles, and a peak power of 2000W. When the laser cuts the wire, a narrow compressed air jet with a pressure of 0.6MPa is introduced in a direction perpendicular to the wire, which is beneficial to the smooth cutting of the wire by the laser.

[0108] S40. Repeat steps S10 to S30 to build the metal truss of the required structure on the substrate.

[0109] The method provided by this invention guides the free end of a wire (the free end being the end of the wire extending from the guide nozzle) to a first target welding point. After welding, the wire is guided to a second target welding point for welding and then cut, forming a wire with both ends welded to a substrate. Through this wire welding and cutting process, a wire-frame truss structure can be manufactured. Then, by layering these structures in the same manner, prisms, cubes, parallelepipeds, icosahedrons, and other similar structures can be formed. To obtain structures with different properties, the wires used can be of the same material or different materials.

[0110] Compared to the layer-by-layer sintering of metal powders, it has the following advantages:

[0111] 19. The production of metal truss structures is highly efficient, with a high product qualification rate and virtually no defective products.

[0112] 20. It has a wide range of applicable materials. It can be used to prepare metal structures made of carbon steel, stainless steel and other materials, as well as metal structures made of aluminum, magnesium, beryllium and other easily oxidized metals and alloys.

[0113] 21. Low manufacturing cost. Because it uses wire, and the wire does not need to be completely melted, energy consumption is reduced, thus lowering production costs.

[0114] 22. 3D printing of truss structures can be achieved without a vacuum environment, saving the time of vacuuming, and the size of the target product is not limited by the size of the vacuum chamber.

[0115] 23. The heat input of the target product is greatly reduced, thus reducing energy consumption costs.

[0116] 24. High material utilization rate: There is almost no filament loss during the 3D printing process.

[0117] Furthermore, to eliminate the defect of wire undercut at the target weld point, in steps S10 and S20, after the welding of the first and second target weld points is completed, a pressure of 40 kgf is applied to the wire along the wire axis. Simultaneously, a laser beam with a power of 2000 W reciprocates along the wire axis around the target weld point, with an amplitude of 2 mm and a frequency of 250 Hz. During the reciprocating motion of the laser beam on the wire, a protective gas with a flow rate of 15 L / min is introduced into the laser-affected zone. The protective gas is argon, helium, carbon dioxide, nitrogen, or a mixture of two or more of these gases. The protective gas is in a laminar flow state in the laser-affected zone, and the cross-sectional area of ​​the laminar flow beam is greater than 5 times the maximum size of the laser-welded molten pool.

[0118] Reference Figure 5 As shown, Figure 5 (a) is a photograph of a wire with undercut defects after welding at the target weld point. Figure 5 (b) is a diagram showing the effect of repairing the edge bite of the wire using this method.

[0119] When it is necessary to build a planar structure on a substrate, such as a three-dimensional structure that requires a continuous surface shell or a continuous surface inside as a partition or reinforcing rib, the following steps are used:

[0120] S100. Multiple wires are welded to the substrate in parallel with each other using the methods described in steps S10 to S30, with adjacent wires in contact with each other.

[0121] S200. A laser beam with a power of 2000W and a moving speed of 5m / min is used to weld the joints between adjacent wires, achieving a connection of the entire length of the adjacent wires. (Refer to...) Figure 3 As shown, Figure 3 (a) and Figure 3 (b) shows a schematic diagram and a partial schematic diagram of the structure with wires welded side by side parallel to the substrate. The planar structure can be constructed by welding the wires side by side parallel to the substrate.

[0122] S300. Along the axial direction of the wire, with an energy density of 10 8 A laser beam of W / cm² is used to perform oscillating scanning on the filament. The laser beam oscillates at a frequency of 300Hz, and the amplitude of the oscillation is three times the diameter of the filament. (Refer to...) Figure 4 As shown, Figure 4 (a) and Figure 4 (b) are schematic diagrams and partial schematic diagrams showing the effect after this step. After the wire is assembled and welded, the wire is oscillating and scanning to form an outer surface or partition with a thickness not less than the radius of the wire. The surface is flat, eliminating the concavity between the wires caused by the shape of the wire.

[0123] S400. Based on the required dimensions of the planar structure, repeat steps S100 to S300 to complete the welding of single or multiple layers to form the required planar structure.

[0124] When the lead screw is made of aluminum, magnesium, beryllium, or other easily oxidized metals or their alloys, the welding process in steps S100 to S200 can employ a combination of laser beam and variable polarity plasma arc welding, wherein the laser beam power is 2000W, the exposure time is 0.4s, the current pulse frequency of the variable polarity plasma arc is 500Hz, the positive polarity current is 50A, and the reverse polarity current is 30A.

[0125] When the lead screw is made of aluminum, magnesium, beryllium or other easily oxidized metals or their alloys, the welding process in steps S100 to S200 can be performed using variable polarity plasma arc welding. The frequency of the variable polarity plasma arc is 500Hz, the positive polarity current is 100A, and the reverse polarity current is 50A.

[0126] In step S300, the wire scanning welding can be performed using a combination of laser beam and plasma arc welding, with the power ratio of the laser beam to the plasma arc being 1:3.

[0127] In step S300, the wire scanning welding can be performed using variable polarity plasma arc welding, with an arc power of 6000W and a positive polarity current of 150A.

[0128] 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 them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fabricating metal truss structures using high-energy beam 3D printing, characterized in that, Includes the following steps: S10. The free end of a metal wire with a diameter of 0.8mm to 4mm is drawn to the first target welding point on the substrate. The focal point of a laser beam with a power of no more than 2000W is aligned with the first target welding point for spot welding, so that one end of the wire is welded to the substrate. The exposure time of the laser beam is 0.04s to 0.4s. S20. Pull the wire toward the second target weld point on the substrate so that the wire contacts the second target weld point on the substrate, and weld the wire to the substrate at the second target weld point in the same way as welding the wire to the first target weld point; S30. At the second target welding point, the wire is cut using a single-pulse laser with a duration of 1ms to 10ms or a multi-pulse laser with a pulse period of 1ms to 1s, an action time of 10 to 100 pulse cycles, and a peak power of 200w to 2000w. S40. Repeat steps S10 to S30 to build the metal truss of the required structure on the substrate; In steps S10 and S20, after the welding of the first and second target weld points is completed, a pressure of 2 kgf to 40 kgf is applied to the wire along the wire axis. At the same time, a laser beam with a power of 200 W to 2000 W is used to perform a reciprocating scanning motion on the wire around the target weld points along the wire axis. The amplitude of the reciprocating scanning motion is 0.1 mm to 2 mm, and the frequency is 50 Hz to 250 Hz.

2. The method for fabricating a metal truss structure using high-energy beam 3D printing according to claim 1, characterized in that: During the reciprocating scanning motion of the laser beam on the wire, a protective gas with a flow rate of 5 L / min to 15 L / min is introduced into the laser action area; the protective gas is a mixture of one or more of the following gases: argon, helium, carbon dioxide, and nitrogen.

3. The method for fabricating a metal truss structure using high-energy beam 3D printing according to claim 2, characterized in that: The protective gas is in a laminar flow state in the laser-acting zone, and the cross-sectional area of ​​the protective gas laminar flow beam is more than 5 times the maximum size of the laser welding molten pool.

4. The method for fabricating a metal truss structure using high-energy beam 3D printing according to claim 1, characterized in that: In step S30, when the laser cuts the filament, a narrow compressed air jet with a pressure of 0.2MPa to 0.6MPa is introduced in a direction perpendicular to the filament.

5. A method for fabricating planar structures using high-energy beam 3D printing, characterized in that, When it is necessary to build a planar structure on a substrate, the following steps are used: S100. Multiple wires are welded to the substrate in parallel with each other using the method described in steps S10 to S30 of claim 1, and adjacent wires are in contact with each other. S200. A laser beam with a power of 200w to 2000w and a moving speed of 0.5m / min to 5m / min is used to weld the joint between adjacent wires, so that the adjacent wires can be connected along the entire length of the wire. S300. Along the axial direction of the wire, with an energy density of 10 5 W / cm² ~ 10 8 A laser beam of W / cm² is used to perform oscillating scanning on the filament. The oscillation frequency of the laser beam is 30Hz to 300Hz, and the amplitude of the laser beam oscillation is at least 2.5 times the diameter of the filament. S400. Based on the required dimensions of the planar structure, repeat steps S100 to S300 to complete the welding of single or multiple layers to form the required planar structure.

6. The method for fabricating planar structures using high-energy beam 3D printing according to claim 5, characterized in that: The wire material is aluminum, magnesium, or beryllium. The welding process in steps S100 to S200 adopts a combination of laser beam and variable polarity plasma arc welding. The exposure time is 0.04s to 0.4s, the current pulse frequency of the variable polarity plasma arc is 100Hz to 500Hz, the positive polarity current is 5A to 50A, and the reverse polarity current is 3A to 30A.

7. A method for fabricating planar structures using high-energy beam 3D printing according to claim 6, characterized in that: In step S300, the wire scanning welding adopts a combination of laser beam and plasma arc welding, and the power ratio of the laser beam and plasma arc is 1:1 to 1:3.

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