Annular light spot laser material increasing system and technological method

Abstract

The invention relates to an annular light spot laser additive material system and a technological method.The annular light spot laser additive material system comprises a laser device, a light path transmission system and a powder transmission system.The laser device outputs light beams to the light path transmission system through an optical fiber connector; light beams output by the laser device comprise a central light spot 100 and an annular light spot 200; the light path transmission system focuses the central light spot 100 and the annular light spot 200, so that the central light spot 100 and the annular light spot 200 are converged at one point on a forming surface to form a laser spot irradiation area; the powder conveying system is arranged between the center light spot 100 and the annular light spot 200, and after being carried by inert gas, powder to be machined is conveyed to the laser spot irradiation area through the powder conveying system. The high powder utilization rate can be achieved, powder waste and powder pollution are reduced, and high-quality additive manufacturing forming machining is achieved.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a ring-shaped spot laser additive system and a process method. Background Art

[0002] At present, in the selective laser melting (SLM) technology, usually after the powder bed is spread, a Gaussian beam and a galvanometer scanning system are used to scan and sinter the powder layer by layer. In this process, only the powder in the selected area is sintered, and the remaining powder needs to be sieved, dried and reused, which can easily cause powder contamination and affect the quality of subsequent part molding. At the same time, the energy distribution of the Gaussian beam is too concentrated, which can easily cause stress concentration in the molded parts, and the molded parts are prone to deformation after cooling to room temperature. In addition, the powder spreading method and powder feeding method used in this additive manufacturing method are very likely to cause powder waste and powder contamination, affecting the quality of workpiece molding.

[0003] In view of this, how to overcome the defects of the above-mentioned prior art and how to solve at least one of the above-mentioned technical problems is a difficult problem to be solved urgently in the field of this technology. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a ring-shaped spot laser additive system and process method, wherein the powder transmission system is arranged between the central spot and the ring-shaped spot, that is, the powder is delivered between the central spot and the ring-shaped spot, and the powder is delivered to the laser spot irradiation area through the inert gas output. In this process, the powder is completely contained in the laser, thereby achieving high powder utilization, reducing powder waste and powder pollution, and achieving high-quality additive manufacturing and forming. On the other hand, compared with the traditional Gaussian beam, the ring-shaped spot can form a more uniform energy coverage on the material surface when processing, effectively avoiding the problems of local overheating and stress concentration caused by excessive energy concentration; this uniform energy distribution not only reduces the risk of deformation of parts during processing, but also improves the dimensional accuracy and surface quality of parts; furthermore, the process window of the ring-shaped spot is wider, and during processing, the laser power and spot parameters can be flexibly adjusted according to specific needs to achieve the best processing effect.

[0005] The present invention is achieved in that:

[0006] In a first aspect, the present invention provides a ring-shaped spot laser additive system, comprising a laser, an optical path transmission system and a powder transmission system, wherein:

[0007] The laser output beam is output to the optical transmission system via an optical fiber connector, and the laser output beam includes a central light spot 100 and an annular light spot 200;

[0008] The optical transmission system focuses the central light spot 100 and the annular light spot 200 so that the central light spot 100 and the annular light spot 200 converge at one point on the molding surface to form a laser light spot irradiation area;

[0009] The powder transmission system is arranged between the central light spot 100 and the annular light spot 200. The powder to be processed is carried by the inert gas and then transported to the laser spot irradiation area through the powder transmission system.

[0010] In some embodiments, the optical path transmission system includes a conical reflector 1 and an arc-shaped focusing mirror 2, the conical reflector 1 includes a conical reflective surface 101 and a vertical focusing mirror 102 arranged in the middle of the conical reflective surface 101, and the arc-shaped focusing mirror 2 is arranged on the periphery of the conical reflective surface 101; the central light spot 100 is vertically emitted after passing through the vertical focusing mirror 102 and is focused on the molding surface; the annular light spot 200 is reflected by the conical reflective surface 101 and then emitted toward the arc-shaped focusing mirror 2, and is reflected by the arc-shaped focusing mirror 2 and focused on the molding surface; the central light spot 100 and the annular light spot 200 converge at a point on the molding surface to form a laser spot irradiation area.

[0011] In some embodiments, the optical path transmission system also includes a conical lens 3, which includes an upper transmission plane 301, a conical transmission surface 302 and a lower center plane 303; the central light spot 100 is transmitted through the upper transmission plane 301 and the lower center plane 303 in sequence and then vertically emitted to the vertical focusing mirror 102 of the conical reflector 1; the annular light spot 200 is transmitted through the upper transmission plane 301 and the conical transmission surface 302 in sequence and then emitted to the conical reflection surface 101 of the conical reflector 1.

[0012] In some embodiments, the distance between the conical lens 3 and the reflector 1 is adjustable.

[0013] In some embodiments, the optical transmission system further includes a collimating lens 4 , and the central light spot 100 and the annular light spot 200 are collimated by the collimating lens 4 and then emitted to the upper transmission plane 301 of the conical lens 3 .

[0014] In some embodiments, the powder delivery system includes an annular powder delivery nozzle, which includes a conical inner wall 5 and a conical outer wall 6, and the gap between the conical inner wall 5 and the conical outer wall 6 forms a first powder delivery channel 7; the conical inner wall 5 is hollow and a light hole 8 is formed on the bottom surface, and a plurality of first small holes 9 are arranged near the bottom of the conical outer wall 6; the conical reflector 1 is provided with an internal transmission channel, and the first powder delivery channel 7 corresponds to the position of the internal transmission channel; the central light spot 100 passes through the After passing through the vertical focusing mirror 102, it passes through the hollow part of the conical inner wall 5, is vertically emitted from the light hole 8, and is focused on the molding surface; after being reflected by the arc-shaped focusing mirror 2, the annular light spot 200 is focused on the molding surface along the outer side of the conical outer wall 6; the central light spot 100 and the annular light spot 200 converge at one point on the molding surface to form a laser spot irradiation area; the powder to be processed passes through the internal transmission channel and the first powder feeding channel 7 in turn, and is transported to the laser spot irradiation area.

[0015] In some embodiments, the powder delivery system includes a multi-point powder delivery nozzle, which includes a hollow conical nozzle 10 and a plurality of hollow powder delivery tubes 11 arranged around the conical nozzle 10; the hollow portion of the conical nozzle 10 forms a light passage 12, the hollow portion of the powder delivery tube 11 forms a second powder delivery channel 13, and the powder delivery tube 11 is provided with a plurality of second small holes 14 near the bottom; the conical reflector 1 is provided with an internal transmission channel, and the second powder delivery channel 13 is located adjacent to the internal transmission channel The central light spot 100 passes through the vertical focusing mirror 102, passes along the light passage 12, and is focused on the molding surface; the annular light spot 200 is reflected by the arc focusing mirror 2, and is focused on the molding surface along the outer side of the powder feeding tube 11; the central light spot 100 and the annular light spot 200 converge at a point on the molding surface to form a laser spot irradiation area; the powder to be processed passes through the internal transmission channel and the second powder feeding channel 13 in sequence, and is transported to the laser spot irradiation area.

[0016] In some embodiments, the powder delivery pipe 11 includes an angle of 70-80 degrees with the horizontal direction.

[0017] In some embodiments, after the laser output beam is homogenized and optical fiber coupled, a central light spot 100 and annular light spot 200 with uniform energy distribution are directly output from the optical fiber connector, and the power of the central light spot 100 and the annular light spot 200 are independently adjusted; the diameter of the central light spot 100 is 8-100um, the inner diameter of the annular light spot 200 is equal to the diameter of the central light spot 100, and the outer diameter of the annular light spot 200 is 50-400um.

[0018] In a second aspect, the present invention provides a ring-shaped spot laser additive process method, which is applied to the ring-shaped spot laser additive system described in the first aspect, and the method includes:

[0019] The central light spot 100 and the annular light spot 200 output by the laser are output to the collimating lens 4 through the optical fiber connector, and then collimated by the collimating lens 4 and transmitted to the conical lens 3;

[0020] The central light spot 100 passes through the upper transmission plane 301 and the lower central plane 303 in sequence and then directly passes through, and then passes through the vertical focusing mirror 102 and then vertically emits and focuses on the molding surface;

[0021] The annular light spot 200 is enlarged in diameter after passing through the upper transmission plane 301 and the conical transmission surface 302 in sequence, and then is reflected by the conical reflection surface 101 and the arc-shaped focusing mirror 2 in sequence and then focused on the molding surface; the central light spot 100 and the annular light spot 200 converge at one point on the molding surface to form a laser light spot irradiation area;

[0022] The powder to be processed is carried by the inert gas and transported to the laser spot irradiation area in sequence along the internal transmission channel of the conical reflector 1 and the first powder feeding channel 7 of the annular powder feeding nozzle; or transported to the laser spot irradiation area along the internal transmission channel of the conical reflector 1 and the second powder feeding channel 13 of the multi-point powder feeding nozzle; wherein the first powder feeding channel 7 and the second powder feeding channel 13 are both arranged between the central spot 100 and the annular spot 200.

[0023] Compared with the prior art, the beneficial effects of the present invention are: providing a ring-shaped spot laser additive system and process method, setting the powder transmission system between the central spot and the ring-shaped spot, that is, adopting a powder delivery method in which the powder is located between the central spot and the ring-shaped spot, and the powder is delivered to the laser spot irradiation area through the inert gas output. In this process, the powder is completely contained in the laser, thereby achieving high powder utilization, reducing powder waste and powder pollution, and achieving high-quality additive manufacturing and forming processing.

[0024] On the other hand, compared with the traditional Gaussian beam, the annular spot used for processing can form a more uniform energy coverage on the material surface, effectively avoiding the problems of local overheating and stress concentration caused by excessive energy concentration; this uniform energy distribution not only reduces the risk of part deformation during processing, but also improves the dimensional accuracy and surface quality of the parts; furthermore, the process window of the annular spot is wider, and during the processing, the laser power and spot parameters can be flexibly adjusted according to specific needs to achieve the best processing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of optical path transmission of a ring-shaped spot laser additive system provided by an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the structure of the annular powder feeding nozzle provided by an embodiment of the present invention from a first viewing angle;

[0028] Figure 3 A schematic structural diagram of an enlarged bottom portion of an annular powder feeding nozzle provided by an embodiment of the present invention at a second viewing angle;

[0029] Figure 4 A schematic diagram of the structure of a multi-point powder feeding nozzle provided by an embodiment of the present invention from a first viewing angle;

[0030] Figure 5 A schematic structural diagram of an enlarged bottom portion of a multi-point powder feeding nozzle provided by an embodiment of the present invention at a second viewing angle;

[0031] Figure 6 A flow chart of a ring-shaped spot laser additive process method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as open inclusion, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "examples", "specific examples" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner, that is, although they may be carried in the embodiments or examples of the above terms due to reasons such as the order and position of appearance, it is not limited to that they can be carried in combination by one embodiment or example.

[0033] In the description of the present invention, the terms "inside", "outside", "longitudinal", "lateral", "up", "down", "left", "right", "top", "bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0034] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0035] It should be noted that, if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, all within the scope of protection of this application. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms and directions used in this specification are only for the purpose of describing specific implementation methods and are not intended to limit the present invention.

[0036] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0037] Example 1

[0038] refer to Figure 1As shown, Embodiment 1 of the present invention provides a ring-shaped spot laser additive system, including a laser, an optical path transmission system and a powder transmission system, wherein: the laser output beam is output to the optical path transmission system through an optical fiber connector, and the laser output beam includes a central spot 100 and a ring-shaped spot 200; the optical path transmission system focuses the central spot 100 and the ring-shaped spot 200, so that the central spot 100 and the ring-shaped spot 200 converge at a point on the molding surface to form a laser spot irradiation area; the powder transmission system is arranged between the central spot 100 and the ring-shaped spot 200, and the powder to be processed is carried by an inert gas and then transported to the laser spot irradiation area through the powder transmission system. In this process, the powder to be processed is always kept in the range between the central spot 100 and the ring-shaped spot 200, realizing the method of powder delivery in the light, improving the powder utilization rate, reducing powder waste and powder pollution, and realizing high-quality additive manufacturing molding processing. Moreover, the use of annular spot for processing can form a more uniform energy coverage on the material surface, effectively avoiding the problems of local overheating and stress concentration caused by excessive energy concentration.

[0039] In some embodiments, after the laser output beam is homogenized and coupled with an optical fiber, a central light spot 100 and an annular light spot 200 with uniform energy distribution are directly output from the optical fiber connector, and the power of the central light spot 100 and the annular light spot 200 are independently adjusted; the diameter of the central light spot 100 is 8-100um, the inner diameter of the annular light spot 200 is equal to the diameter of the central light spot 100, and the outer diameter of the annular light spot 200 is 50-400um. The laser output beam is output to the optical path transmission system through the QBH / QD / LLK-D optical fiber connector.

[0040] In some embodiments, the optical path transmission system includes a conical reflector 1 and an arc-shaped focusing mirror 2, the conical reflector 1 includes a conical reflective surface 101 and a vertical focusing mirror 102 arranged in the middle of the conical reflective surface 101, and the arc-shaped focusing mirror 2 is arranged on the periphery of the conical reflective surface 101; the central light spot 100 is vertically emitted after passing through the vertical focusing mirror 102 and is focused on the molding surface; the annular light spot 200 is reflected by the conical reflective surface 101 and then emitted toward the arc-shaped focusing mirror 2, and is reflected by the arc-shaped focusing mirror 2 and focused on the molding surface; the central light spot 100 and the annular light spot 200 converge at a point on the molding surface to form a laser spot irradiation area. By reflecting the annular light spot 200 outward through the conical reflection surface 101 and then focusing it through the arc focusing mirror 2, the gap between the annular light spot 200 and the central light spot 100 can be increased, so that the powder transmission system can be better arranged between the annular light spot 200 and the central light spot 100, making it easier to realize the transmission method of intra-light powder delivery.

[0041] In some embodiments, the optical transmission system further includes a conical lens 3, which includes an upper transmission plane 301, a conical transmission surface 302, and a lower center plane 303; the central light spot 100 is transmitted through the upper transmission plane 301 and the lower center plane 303 in sequence and then vertically irradiates the vertical focusing lens 102 of the conical reflector 1; the annular light spot 200 is transmitted through the upper transmission plane 301 and the conical transmission surface 302 in sequence and then irradiates the conical reflection surface 101 of the conical reflector 1. The conical lens 3 can be provided to enlarge the diameter of the annular light spot 200; and in some embodiments, the distance between the conical lens 3 and the reflector 1 is adjustable, and the diameter of the annular light spot 200 can be changed by adjusting the upper and lower positions of the conical lens 3.

[0042] In some embodiments, the optical transmission system further includes a collimating lens 4. After being collimated by the collimating lens 4, the central light spot 100 and the annular light spot 200 are emitted toward the upper transmission plane 301 of the conical lens 3, and then undergo subsequent optical transmission.

[0043] in addition, Figure 1 The powder delivery channel 300 is also included. When the powder delivery system adopts an annular powder delivery nozzle, the powder delivery channel 300 corresponds to the first powder delivery channel 7. At this time, the first powder delivery channel 7 and the internal transmission channel of the conical reflector 1 are combined to form a complete powder delivery channel 300. When the powder delivery system adopts a multi-point powder delivery nozzle, the powder delivery channel 300 corresponds to the second powder delivery channel 13. At this time, the second powder delivery channel 13 and the internal transmission channel of the conical reflector 1 are combined to form a complete powder delivery channel 300.

[0044] refer to Figure 2 and Figure 3As shown, in some embodiments, the powder delivery system includes an annular powder delivery nozzle, the annular powder delivery nozzle includes a conical inner wall 5 and a conical outer wall 6, the gap between the conical inner wall 5 and the conical outer wall 6 forms a first powder delivery channel 7; the conical inner wall 5 is hollow and a light hole 8 is formed on the bottom surface, and a plurality of first small holes 9 are arranged near the bottom of the conical outer wall 6; the conical reflector 1 is provided with an internal transmission channel, and the first powder delivery channel 7 corresponds to the position of the internal transmission channel; the central light spot 100 passes through After passing through the vertical focusing mirror 102, the powder passes through the hollow part of the conical inner wall 5, and is vertically emitted from the light hole 8, and is focused on the molding surface; after being reflected by the arc focusing mirror 2, the annular light spot 200 is focused on the molding surface along the outer side of the conical outer wall 6; the central light spot 100 and the annular light spot 200 converge at one point on the molding surface to form a laser light spot irradiation area; the powder to be processed passes through the internal transmission channel and the first powder feeding channel 7 in sequence, and is transported to the laser light spot irradiation area. In this process, the powder to be processed is located between the central light spot 100 and the annular light spot 200, and the powder is completely surrounded by the central light spot 100 and the annular light spot 200, realizing the powder feeding in the light, thereby realizing the high-efficiency molding processing of the powder. The minimum particle size of the powder to be processed in this embodiment is 30-150um, and the diameter of the first small holes 9 near the bottom is 20um to release the inert protective gas carried by the powder, reduce the movement speed of the powder, thereby reducing the collision of the powder, so that the powder can be evenly delivered into the light spot.

[0045] refer to Figure 4 and Figure 5As shown, in some embodiments, the powder delivery system includes a multi-point powder delivery nozzle, and the multi-point powder delivery nozzle includes a hollow conical nozzle 10 and a plurality of hollow powder delivery tubes 11 arranged around the conical nozzle 10; the hollow portion of the conical nozzle 10 forms a light passage 12, and the hollow portion of the powder delivery tube 11 forms a second powder delivery channel 13, and the powder delivery tube 11 is provided with a plurality of second small holes 14 near the bottom; the conical reflector 1 is provided with an internal transmission channel, and the second powder delivery channel 13 and the internal transmission channel The positions correspond; after the central light spot 100 passes through the vertical focusing mirror 102, it passes along the light passage 12 and is focused on the molding surface; after the annular light spot 200 is reflected by the arc focusing mirror 2, it is focused on the molding surface along the outer side of the powder feeding tube 11; the central light spot 100 and the annular light spot 200 converge at one point on the molding surface to form a laser light spot irradiation area; the powder to be processed passes through the internal transmission channel and the second powder feeding channel 13 in turn and is transported to the laser light spot irradiation area. In this process, the powder to be processed is located between the central light spot 100 and the annular light spot 200, and the powder is completely surrounded by the central light spot 100 and the annular light spot 200, realizing the powder feeding in the light, thereby realizing the high-efficiency molding processing of the powder. The minimum particle size of the powder to be processed in this embodiment is 30-150um, and the diameter of the second small holes 14 near the bottom is 20um to release the inert protective gas carried by the powder, reduce the movement speed of the powder, thereby reducing the collision of the powder, so that the powder can be evenly delivered into the light spot.

[0046] Need to explain, Figure 4 and Figure 5 The three-point powder feeding nozzle is used as an example to illustrate the structure. If the four-point powder feeding nozzle or other multi-point powder feeding nozzle has a similar structure, it will not be repeated here. In some embodiments, when a three-point powder feeding nozzle or a four-point powder feeding nozzle is used, the angle between the powder feeding tube 11 and the horizontal direction is 70-80 degrees.

[0047] Next, a comparative analysis of the powder feeding efficiency of this embodiment and the traditional powder feeding efficiency is performed.

[0048] For the existing powder feeding methods: using external light powder feeding and powder spreading, the powder spreading method is very likely to cause powder waste and powder pollution, and the quality of the additive parts will be affected when the powder is reused. At the same time, the additive efficiency is low, the thickness of each powder spreading layer is 30um, the spot diameter is about 100um, the maximum laser scanning speed is about 1200mm / s, and its forming efficiency is about 0.06mm 3 / min, the forming efficiency is low. In addition, the existing method of using external light powder feeding generally uses three-point, four-point or ring-shaped powder feeding to achieve external light coaxial powder feeding, and its multi-path powder collides and diverges in space. This method has a low powder utilization rate of about 50%-70%.

[0049] For the powder feeding method of the embodiment of the present invention: the powder feeding method is adopted, the powder can be controlled to be uniformly transported into the light, and the powder feeding method is adopted to reduce the collision of powders, so that the powders are evenly scattered at the focal position; the utilization rate of powders can exceed 90%. Compared with the traditional external light powder feeding, the utilization rate is increased by 1.5-2 times. In addition, the powder feeding nozzle can be a three-point, four-point and annular powder feeding nozzle. The center position of the powder feeding nozzle passes through the central light spot. The annular light spot after passing through the optical path transmission system is outside the outer wall of the powder feeding nozzle, and then converges with the central light spot at the focal plane; the powder is transported to the focal plane in the middle gap of the annular nozzle. For the bottom of the powder feeding nozzle, the minimum particle size of the powder used in the embodiment of the present invention is 30-150um, and there are several circles of 20um small holes near the bottom position to discharge the inert protective gas carried by the powder, reduce the movement speed of the powder, thereby reducing the collision of the powder, so that the powder can be uniformly fed into the light spot, so that it can be melted under the action of the high-energy laser beam to achieve additive manufacturing.

[0050] In summary, the embodiment of the present invention provides a ring-shaped spot laser additive system. The power of the central spot and the ring-shaped spot output by the laser can be adjusted independently. Then, the central spot and the ring-shaped spot are split and transmitted respectively through the optical transmission system and focused on the surface of the workpiece. Through a special powder feeding system, the powder is output through the inert gas and sent to the focal point of the central spot and the ring-shaped spot. The powder is completely contained in the laser, thereby achieving high powder utilization and high-quality additive manufacturing processing.

[0051] At the same time, the energy distribution of the Gaussian beam is too concentrated, which can easily cause stress concentration in the molded parts, and the molded parts are prone to deformation after cooling to room temperature. Compared with the traditional Gaussian beam, the annular spot used in the embodiment of the present invention can form a more uniform energy coverage on the material surface, effectively avoiding the problems of local overheating and stress concentration caused by excessive energy concentration. This uniform energy distribution not only reduces the risk of part deformation during processing, but also improves the dimensional accuracy and surface quality of the parts. In addition, the process window of the annular spot is wider. During the processing, the laser power and spot parameters can be flexibly adjusted according to specific needs to achieve the best processing effect.

[0052] Example 2

[0053] refer to Figure 6 As shown, this embodiment provides a ring-shaped spot laser additive process method, which is applied to the ring-shaped spot laser additive system described in Example 1, and the method includes the following steps.

[0054] Step 100: The central spot 100 and the annular spot 200 output by the laser are output to the collimating lens 4 through the optical fiber connector, and then transmitted to the conical lens 3 after being collimated by the collimating lens 4. The laser output beam is output to the optical transmission system through the QBH / QD / LLK-D optical fiber connector; the light spot is first collimated by the collimating lens 4 and then transmitted to the conical lens 3.

[0055] Step 200: The central light spot 100 passes through the upper transmission plane 301 and the lower central plane 303 in sequence, then directly passes through, and then passes through the vertical focusing mirror 102, then is vertically emitted, and is focused on the molding surface. The central light spot 100 passes through the central plane of the conical lens 3, then passes through the vertical focusing mirror 102, then is vertically emitted.

[0056] Step 300: The annular light spot 200 is enlarged in diameter after passing through the upper transmission plane 301 and the conical transmission surface 302 in sequence, and then is focused on the molding surface after being reflected by the conical reflection surface 101 and the arc-shaped focusing mirror 2 in sequence; the central light spot 100 and the annular light spot 200 converge at a point on the molding surface to form a laser spot irradiation area.

[0057] Step 400: The powder to be processed is carried by the inert gas and sequentially transported to the laser spot irradiation area along the internal transmission channel of the conical reflector 1 and the first powder feeding channel 7 of the annular powder feeding nozzle; or transported to the laser spot irradiation area along the internal transmission channel of the conical reflector 1 and the second powder feeding channel 13 of the multi-point powder feeding nozzle; wherein the first powder feeding channel 7 and the second powder feeding channel 13 are both arranged between the central spot 100 and the annular spot 200. The powder transmission system is located between the central spot 100 and the annular spot 200, and the powder to be processed is carried by the inert gas and sequentially passes through the internal transmission channel of the conical reflector 1, the first powder feeding channel 7 or the second powder feeding channel 13, and is transported to the laser spot irradiation area, and the powder is completely surrounded by the central spot 100 and the annular spot 200, thereby realizing high-efficiency molding processing of the powder. In addition, the laser power of the central spot 100 and / or the annular spot 200 can be adjusted separately according to different material properties, so as to reach the energy density threshold of powder melting and realize powder additive manufacturing.

[0058] In summary, an embodiment of the present invention provides a ring-shaped spot laser additive process method, in which a powder transmission system is arranged between the central spot and the ring-shaped spot, that is, the powder is delivered in a manner in which the powder is located between the central spot and the ring-shaped spot. The powder is delivered to the laser spot irradiation area through the inert gas output. In this process, the powder is completely contained in the laser, thereby achieving high powder utilization, reducing powder waste and powder pollution, and achieving high-quality additive manufacturing processing.

[0059] On the other hand, compared with the traditional Gaussian beam, the annular spot used for processing can form a more uniform energy coverage on the material surface, effectively avoiding the problems of local overheating and stress concentration caused by excessive energy concentration; this uniform energy distribution not only reduces the risk of part deformation during processing, but also improves the dimensional accuracy and surface quality of the parts; furthermore, the process window of the annular spot is wider, and during the processing, the laser power and spot parameters can be flexibly adjusted according to specific needs to achieve the best processing effect.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ring-shaped spot laser additive system, characterized in that: It includes laser, optical transmission system and powder transmission system, among which: The laser output beam is output to the optical transmission system via an optical fiber connector, and the laser output beam comprises a central light spot (100) and an annular light spot (200); The optical path transmission system focuses the central light spot (100) and the annular light spot (200), so that the central light spot (100) and the annular light spot (200) converge at a point on the molding surface to form a laser light spot irradiation area; The powder transmission system is arranged between the central light spot (100) and the annular light spot (200), and the powder to be processed is carried by the inert gas and then transported to the laser light spot irradiation area through the powder transmission system.

2. The annular spot laser additive system according to claim 1, characterized in that: The optical path transmission system comprises a conical reflector (1) and an arc-shaped focusing mirror (2); the conical reflector (1) comprises a conical reflective surface (101) and a vertical focusing mirror (102) arranged in the middle of the conical reflective surface (101); the arc-shaped focusing mirror (2) is arranged on the periphery of the conical reflective surface (101); the central light spot (100) is emitted vertically after passing through the vertical focusing mirror (102) and is focused on a molding surface; the annular light spot (200) is reflected by the conical reflective surface (101) and then emitted toward the arc-shaped focusing mirror (2), and is reflected by the arc-shaped focusing mirror (2) and is focused on the molding surface; the central light spot (100) and the annular light spot (200) converge at a point on the molding surface to form a laser light spot irradiation area.

3. The annular spot laser additive system according to claim 2, characterized in that: The optical path transmission system also includes a conical lens (3), and the conical lens (3) includes an upper transmission plane (301), a conical transmission surface (302), and a lower center plane (303); the central light spot (100) is transmitted through the upper transmission plane (301) and the lower center plane (303) in sequence, and then vertically irradiates the vertical focusing mirror (102) of the conical reflector (1); the annular light spot (200) is transmitted through the upper transmission plane (301) and the conical transmission surface (302) in sequence, and then irradiates the conical reflection surface (101) of the conical reflector (1).

4. The annular spot laser additive system according to claim 3, characterized in that: The distance between the conical lens (3) and the reflector (1) is adjustable.

5. The annular spot laser additive system according to claim 3, characterized in that: The optical path transmission system further comprises a collimating lens (4), and the central light spot (100) and the annular light spot (200) are collimated by the collimating lens (4) and then emitted toward the upper transmission plane (301) of the conical lens (3).

6. The annular spot laser additive system according to claim 2, characterized in that: The powder transmission system comprises an annular powder delivery nozzle, the annular powder delivery nozzle comprises a conical inner wall (5) and a conical outer wall (6), the gap between the conical inner wall (5) and the conical outer wall (6) forms a first powder delivery channel (7); the conical inner wall (5) is hollow and a light hole (8) is formed on the bottom surface, and a plurality of first small holes (9) are arranged near the bottom of the conical outer wall (6); the conical reflector (1) is provided with an internal transmission channel, and the first powder delivery channel (7) corresponds to the position of the internal transmission channel; the central light spot (100) passes through the vertical After passing through the straight focusing mirror (102), the light passes through the hollow part of the conical inner wall (5), is vertically emitted from the light hole (8), and is focused on the molding surface; after being reflected by the arc-shaped focusing mirror (2), the annular light spot (200) is focused on the molding surface along the outer side of the conical outer wall (6); the central light spot (100) and the annular light spot (200) converge at one point on the molding surface to form a laser light spot irradiation area; the powder to be processed passes through the internal transmission channel and the first powder feeding channel (7) in sequence, and is then transported to the laser light spot irradiation area.

7. The annular spot laser additive system according to claim 2, characterized in that: The powder transmission system comprises a multi-point powder delivery nozzle, the multi-point powder delivery nozzle comprises a hollow conical nozzle (10) and a plurality of hollow powder delivery tubes (11) arranged around the conical nozzle (10); the hollow portion of the conical nozzle (10) forms a light passage (12), the hollow portion of the powder delivery tube (11) forms a second powder delivery channel (13), and the powder delivery tube (11) is provided with a plurality of second small holes (14) near the bottom; the conical reflector (1) is provided with an internal transmission channel, and the second powder delivery channel (13) is located opposite to the internal transmission channel. The central light spot (100) passes through the vertical focusing mirror (102), passes along the light passage (12), and is focused on the molding surface; the annular light spot (200) is reflected by the arc-shaped focusing mirror (2), and is focused on the molding surface along the outer side of the powder feeding tube (11); the central light spot (100) and the annular light spot (200) converge at a point on the molding surface to form a laser light spot irradiation area; the powder to be processed passes through the internal transmission channel and the second powder feeding channel (13) in sequence, and is then transported to the laser light spot irradiation area.

8. The annular spot laser additive system according to claim 7, characterized in that: The angle between the powder delivery pipe (11) and the horizontal direction is 70-80 degrees.

9. The annular spot laser additive system according to any one of claims 1 to 8, characterized in that: After the laser output light beam is homogenized and optical fiber coupled, a central light spot (100) and an annular light spot (200) with uniform energy distribution are directly output from the optical fiber connector, and the power of the central light spot (100) and the annular light spot (200) are independently adjusted; the diameter of the central light spot (100) is 8-100 um, the inner diameter of the annular light spot (200) is equal to the diameter of the central light spot (100), and the outer diameter of the annular light spot (200) is 50-400 um.

10. A ring-shaped spot laser additive process method, applied to the ring-shaped spot laser additive system according to any one of claims 1 to 9, characterized in that: include: The central light spot (100) and the annular light spot (200) output by the laser are output to the collimating lens (4) via the optical fiber connector, and are collimated by the collimating lens (4) and then transmitted to the conical lens (3); The central light spot (100) passes through the upper transmission plane (301) and the lower central plane (303) in sequence and then directly passes through, and then passes through the vertical focusing mirror (102) and then vertically emits and is focused on the molding surface; The annular light spot (200) is enlarged in diameter after passing through the upper transmission plane (301) and the conical transmission surface (302) in sequence, and then is focused on the molding surface after being reflected by the conical reflection surface (101) and the arc-shaped focusing mirror (2); the central light spot (100) and the annular light spot (200) converge at a point on the molding surface to form a laser light spot irradiation area; The powder to be processed is carried by inert gas and transported to the laser spot irradiation area in sequence along the internal transmission channel of the conical reflector (1) and the first powder feeding channel (7) of the annular powder feeding nozzle; or transported to the laser spot irradiation area along the internal transmission channel of the conical reflector (1) and the second powder feeding channel (13) of the multi-point powder feeding nozzle; wherein the first powder feeding channel (7) and the second powder feeding channel (13) are both arranged between the central light spot (100) and the annular light spot (200).

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