Multi-beam laser selective melting and femtosecond composite additive and subtractive optical path system

Abstract

The application discloses a multi-beam laser selective melting and femtosecond composite additive-subtractive optical system, which comprises a femtosecond fiber laser, a continuous fiber laser, a collimating mirror, a beam expander, a galvanometer and a focusing lens, wherein the femtosecond fiber laser, the continuous fiber laser, the beam expander, the galvanometer and the focusing lens are sequentially arranged in a laser transmission direction. The additive optical system and the femtosecond subtractive defect removal optical system are integrated, the structure is compact and simple, and the operation is convenient, and the economic practicability is high.

Description

Technical Field

[0001] This invention relates to the field of laser 3D printing and post-processing, and in particular to a multi-beam laser selective melting and femtosecond composite additive and subtractive optical path system. Background Technology

[0002] Currently, laser 3D printing technology is quite mature, but existing laser 3D printing equipment has the problem of not being able to efficiently combine additive printing and subtractive repair. That is, it cannot simultaneously satisfy the needs of additive printing and subtractive repair; moreover, even if the two are combined, nanosecond lasers are used for subtractive repair, which generally has a small processing size. This makes it impossible to achieve large-size, high-efficiency, and high-precision composite processing of additive printing and subtractive repair; it can only achieve single-path composite processing of the additive printing optical path and the subtractive repair optical path.

[0003] Therefore, there is an urgent need to propose corresponding solutions to address the problems existing in the above-mentioned prior art. Summary of the Invention

[0004] This invention provides a multi-beam laser selective melting and femtosecond composite additive and subtractive optical path system, which aims to solve the problem that existing technologies cannot achieve large-size, high-efficiency, and high-precision composite processing for additive printing and subtractive repair.

[0005] In a first aspect, embodiments of the present invention provide a multi-beam laser selective melting and femtosecond composite additive and subtractive optical path system, the system comprising a femtosecond fiber laser, a continuous fiber laser, a collimating mirror, a beam expander, a galvanometer, and a focusing lens, wherein the femtosecond fiber laser, the continuous fiber laser, the beam expander, the galvanometer, and the focusing lens are arranged sequentially in the laser transmission direction.

[0006] Secondly, embodiments of the present invention provide a method for additive and subtractive composite processing using the system according to claim 1, comprising:

[0007] After collimating the diverging light output from the femtosecond fiber laser and the continuous fiber laser using a collimating lens, the beam is expanded using a beam expander to obtain the femtosecond subtractive beam and the continuous additive beam.

[0008] The optical path transmission direction of the femtosecond subtractive beam is controlled by a reflector, and the beam is reflected to a beam splitter for splitting. Then, the beam enters the dichroic mirror together with the continuous additive beam. Alternatively, the femtosecond subtractive beam is split by a beam splitter, and the split femtosecond subtractive beam is controlled by a reflector to enter the dichroic mirror together with the continuous additive beam.

[0009] The femtosecond subtractive beam is fully transparent and the continuous additive beam is fully reflected by a dichroic mirror. The processed additive and subtractive optical paths are transmitted to the galvanometer and then focused by a focusing lens before being output to the working surface for composite processing.

[0010] This invention provides a multi-beam laser selective melting and femtosecond composite additive / subtractive optical path system. The system includes a femtosecond fiber laser, a continuous fiber laser, a collimating mirror, a beam expander, a galvanometer, and a focusing lens, which are arranged sequentially in the laser propagation direction.

[0011] This application employs an all-fiber soft laser optical path structure. The additive and subtractive material beams output from the fiber laser are modulated by a collimating lens and a beam expander to achieve the laser source required for additive and subtractive composite processing. Then, the additive and subtractive material beams are simultaneously input into a high-precision scanning galvanometer and a high-stability focusing lens, and the laser output and scanning are controlled by a control system. This application integrates an additive optics system and a femtosecond subtractive defect removal optics system, resulting in a compact, simple structure that is easy to operate and highly economical and practical. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the optical path system for multi-beam laser selective melting and femtosecond composite additive / subtractive materials provided in an embodiment of the present invention;

[0014] Figure 2 This is a schematic diagram of the galvanometer focusing system provided in an embodiment of the present invention;

[0015] Figure 3 This is a schematic diagram of the protective gas system of the galvanometer focusing system provided in an embodiment of the present invention;

[0016] Figure 4 This is a flowchart illustrating a method for additive-subtractive composite processing based on a multi-beam laser selective melting and femtosecond composite additive-subtractive optical path system, as provided in an embodiment of the present invention. Detailed Implementation

[0017] 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, not all, of the embodiments of the present invention. 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.

[0018] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0019] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0021] This invention provides a multi-beam laser selective melting and femtosecond composite additive / subtractive optical path system. Figure 1 This is a schematic diagram of the optical path system for multi-beam laser selective melting and femtosecond composite additive / subtractive materials provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the system includes a femtosecond fiber laser, a continuous fiber laser, a collimating lens, a beam expander, a galvanometer, and a focusing lens.

[0022] Specifically, the femtosecond fiber laser, continuous fiber laser, beam expander, galvanometer, and focusing lens are arranged sequentially in the laser propagation direction.

[0023] Figure 2 This is a schematic diagram of the galvanometer focusing system provided in an embodiment of the present invention, as shown below. Figure 2As shown, it should be noted that the scanning galvanometer used in the galvanometer focusing system has a temperature-compensated self-calibration function, which can ensure the accuracy of the galvanometer during the forming process. Its scanning accuracy correction error is ≤50μm. In addition, the scanning galvanometer has high repeatability and a maximum scanning speed of 7m / s on the X and Y axes. Preferably, the system also includes a temperature-controlled water-cooling module, which is used to control the thermal deformation generated by the scanning galvanometer. Its temperature fluctuation value is ≤±0.5℃, which can eliminate product accuracy problems caused by thermal deformation of the scanning galvanometer. The focusing lens in the galvanometer focusing system is a large-size F-thetalens focusing lens, whose lens material is fused silica. The focused spot diameter is 90μm. The optical system has stable beam quality for more than 200 hours of operation, with a forming spot diameter fluctuation of ≤±1μm and a scanning accuracy deviation of ≤±0.1mm.

[0024] Figure 3 This is a schematic diagram of the protective gas system of the galvanometer focusing system provided in an embodiment of the present invention, as shown below. Figure 3 As shown, preferably, a protective lens is provided under the focusing lens (f-theta lens). This protective lens separates the focusing lens and galvanometer from the external environment, preventing dust, impurities, etc. from adhering to the lens surface, which could lead to reduced precision of the molded parts and damage to the optical lens.

[0025] In one embodiment, the optical path system further includes a reflector and a dichroic mirror, such as... Figure 1 As shown, the reflector is positioned behind the beam expander and is coaxial with the beam expander in the laser propagation direction; the dichroic mirror is positioned behind the reflector and is coaxial with the reflector in the laser propagation direction.

[0026] In one embodiment, the optical path system further includes a beam splitter, such as Figure 1 As shown, a beam splitter can be positioned between a reflector and a dichroic mirror, and coaxial with both the reflector and the dichroic mirror in the laser propagation direction, to split the laser beam. Alternatively, the beam splitter can also be positioned between a beam expander and a reflector, and coaxial with both the beam expander and the reflector in the laser propagation direction, to split the laser beam.

[0027] Through the above-described all-fiber soft laser optical path system structure, this embodiment integrates the additive optics system and the femtosecond subtractive defect removal optics system. Its structure is compact and simple, and it is easy to operate and highly economical and practical.

[0028] This embodiment also provides a method for additive-subtractive composite processing based on a multi-beam laser selective melting and femtosecond composite additive-subtractive optical path system. Figure 4 This is a flowchart illustrating a method for additive-subtractive composite processing based on a multi-beam laser selective melting and femtosecond composite additive-subtractive optical path system provided in an embodiment of the present invention. Figure 4 As shown, the method includes steps S410 to S430.

[0029] S410. After collimating the diverging light output from the femtosecond fiber laser and the continuous fiber laser through a collimating lens, the beam is expanded through a beam expander to obtain the femtosecond subtractive beam and the continuous additive beam.

[0030] like Figure 1 As shown, in this embodiment, two femtosecond fiber lasers and four continuous fiber lasers are used to output divergent lasers. Then, the divergent light output by the lasers is collimated by a collimating lens and expanded by a beam expander to obtain a femtosecond subtractive beam and a continuous additive beam.

[0031] S420. The optical path transmission direction of the femtosecond subtractive beam is controlled by a reflector, and the beam is reflected to a beam splitter for splitting. Then, the beam enters the dichroic mirror together with the continuous additive beam. Alternatively, the femtosecond subtractive beam is split by a beam splitter, and the split femtosecond subtractive beam and the continuous additive beam are controlled by a reflector to enter the dichroic mirror together.

[0032] In this embodiment, the optical path transmission direction of the two femtosecond subtractive beams is controlled by a reflector, and the beams are reflected to a beam splitter for splitting. The beams then enter the dichroic mirror together with the four continuous additive beams. Alternatively, the two femtosecond subtractive beams are split by a beam splitter, and the split femtosecond subtractive beams are controlled by a reflector to enter the dichroic mirror together with the four continuous additive beams.

[0033] 430. The femtosecond subtractive beam is fully transparent and the continuous additive beam is fully reflected by a dichroic mirror. The processed additive and subtractive optical paths are transmitted to the galvanometer and focused by the focusing lens before being output to the working surface for composite processing.

[0034] In this embodiment, four femtosecond subtractive beams are fully transparent and four continuous additive beams are fully reflected by a dichroic mirror. The processed additive and subtractive optical paths are transmitted to a galvanometer and focused by a focusing lens before being output to the working surface for composite processing of laser additive printing and femtosecond subtractive defect removal.

[0035] The above methods can be used to form more than 50 kinds of metal powder materials, including but not limited to titanium alloys, aluminum alloys, high-temperature alloys, cobalt-chromium alloys, stainless steel, high-strength steel, mold steel, and nickel-based alloys. These materials can be used for laser selective melting forming and online repair of micro-defects in large and medium-sized, complex metal components. They also enable the addition and subtraction manufacturing of easily oxidized and reactive metal materials, as well as commonly used aerospace metal materials. Furthermore, the formed parts can be widely used in various fields such as aviation, aerospace, automotive, medical, and scientific research.

[0036] This application employs an all-fiber soft laser optical path structure. The additive and subtractive material beams output from the fiber laser are modulated by a collimating lens and a beam expander to achieve the laser source required for additive and subtractive composite processing. Then, the additive and subtractive material beams are simultaneously input into a high-precision scanning galvanometer and a high-stability focusing lens, and the laser output and scanning are controlled by a control system. This application integrates an additive optics system and a femtosecond subtractive defect removal optics system, resulting in a compact, simple structure that is easy to operate and highly economical and practical.

[0037] Those skilled in the art will clearly understand that the above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-beam laser selective melting and femtosecond composite additive and subtractive optical path system, characterized in that, The system comprises a femtosecond fiber laser, a continuous fiber laser, a collimating mirror, a beam expander, a galvanometer and a focusing lens, and the femtosecond fiber laser, the continuous fiber laser, the beam expander, the galvanometer and the focusing lens are sequentially arranged in a laser transmission direction. The two femtosecond fiber lasers and the four continuous fiber lasers respectively output divergent laser, and then the divergent laser output by the lasers is collimated by the collimating mirror, expanded by the beam expander, and the femtosecond subtractive beam and the continuous additive beam are obtained. The system further comprises a reflecting mirror and a dichroic mirror, the reflecting mirror is arranged behind the beam expander and coaxial with the beam expander in the laser transmission direction, and the dichroic mirror is arranged behind the reflecting mirror and coaxial with the reflecting mirror in the laser transmission direction. The system comprises a beam splitter arranged between the reflecting mirror and the dichroic mirror and coaxial with the reflecting mirror and the dichroic mirror in the laser transmission direction, for splitting the laser; or the beam splitter is arranged between the beam expander and the reflecting mirror and coaxial with the beam expander and the reflecting mirror in the laser transmission direction, for splitting the laser. The reflecting mirror controls the light path transmission direction of the two femtosecond subtractive beams, reflects them to the beam splitter for splitting, and then the two femtosecond subtractive beams and the four continuous additive beams enter the dichroic mirror together, or the beam splitter splits the two femtosecond subtractive beams, and then the reflecting mirror controls the split femtosecond subtractive beams and the four continuous additive beams to enter the dichroic mirror together; a protection mirror is arranged below the focusing lens, and the focusing lens, the galvanometer and the external environment are separated by the protection mirror. The system further comprises a temperature control water cooling module for controlling the thermal deformation of the scanning galvanometer.

2. The system of claim 1, wherein, The lens material of the focusing lens is fused quartz.

3. A method of additive-subtractive hybrid machining using the system of claim 1, characterized by, The method comprises the following steps: collimating the divergent laser output by the femtosecond fiber laser and the continuous fiber laser by the collimating mirror, expanding by the beam expander, obtaining the femtosecond subtractive beam and the continuous additive beam; controlling the light path transmission direction of the femtosecond subtractive beam by the reflecting mirror, reflecting it to the beam splitter for splitting, and then the femtosecond subtractive beam and the continuous additive beam enter the dichroic mirror together, or the beam splitter splits the femtosecond subtractive beam, and then the reflecting mirror controls the split femtosecond subtractive beam and the continuous additive beam to enter the dichroic mirror together; the dichroic mirror fully transmits the femtosecond subtractive beam and fully reflects the continuous additive beam, and the processed additive and subtractive beams are transmitted to the galvanometer, and then output after focusing by the focusing lens, so as to reach the working surface for composite machining.

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