Laser printing annular light spot system and laser 3D printing equipment

Abstract

The invention belongs to the technical field of laser optics, and particularly relates to a laser printing annular light spot system and laser 3D printing equipment, and the laser printing annular light spot system comprises a laser, a collimator, a cone lens, a galvanometer system and a field lens; laser beams emitted by the laser device form parallel light beams through the collimator, the formed parallel light beams are refracted by the cone mirror to form annular laser beams which are diffused towards the outer side of the cone or gathered in a cone shape, the laser beams are reflected by the galvanometer system and then penetrate through the field lens, the field lens gathers light and is diffused, and the laser beams are reflected by the galvanometer system. Or the gathered laser beams are refracted, and annular light spots are formed on the same plane, so that the actual laser 3D printing effect is met.

Description

Technical Field

[0001] The present invention belongs to the field of laser optical technology, and in particular relates to a laser printing annular spot system and a laser 3D printing device. Background Art

[0002] Selective laser melting (SLM), as a type of additive manufacturing (AM) technology, can process parts with complex structures and has high finished product forming precision, and is widely used in the fields of medicine, aerospace, etc. At present, most SLM processing equipment uses traditional Gaussian density distribution laser beams (single-mode TEM00 mode). Since the energy at the center of the Gaussian light is higher and the energy at the edge is lower, defects such as metal splashing and pores are often caused during the processing due to uneven energy distribution.

[0003] In order to overcome the above technical defects, the Chinese patent document with publication number CN113649595A discloses an annular spot optical system and printing method for metal SLM printing. It includes a laser, a collimator, a variable-power beam expander, a beam shaping unit, a total reflection mirror, a galvanometer system, a field lens and a working platform are arranged in sequence along the propagation path of the Gaussian beam emitted by the laser, the laser is connected to the collimator through an optical fiber, the Gaussian beam emitted by the laser is collimated by the collimator, the collimated Gaussian beam is adjusted to a spot size by a variable-power beam expander, the beam shaping unit includes a first conical lens and a second conical lens, the Gaussian beam after the spot size is adjusted is shaped by the first conical lens and the second conical lens in sequence, the shaped beam is formed by the total reflection mirror, the galvanometer system and the field lens in sequence to form a focused spot to reach the working platform. The beam shaping unit can automatically switch between various beam forms such as circular Gaussian spot, annular spot, elliptical spot, etc. It can use Gaussian light path, shaped annular spot or elliptical spot for printing alone, and can also use different light paths for printing at different stages of the printing process to meet the research and application needs under multiple working conditions. It not only has a certain degree of integration, but also can realize the use of different light paths for printing at different positions and stages, thereby improving efficiency and avoiding the occurrence of defects in the printing process as much as possible.

[0004] However, in reality, the technical solution disclosed in the patent document cannot effectively form an annular light spot. Summary of the invention

[0005] The purpose of the present invention is to provide a laser printing annular spot system and a laser 3D printing device, which are used to solve the problem that the laser printing in the prior art cannot effectively form an annular spot.

[0006] To achieve the above-mentioned purpose, an embodiment of the present invention provides a laser printing annular spot system, comprising a laser, a collimator, a conical mirror, a galvanometer system and a field lens; the laser beam emitted by the laser is formed into a parallel beam by the collimator, and then refracted by the conical mirror to form a laser beam that diffuses outward in an annular cone or converges in a cone; the laser beam is reflected by the galvanometer system and penetrates the field lens to form an annular spot on a plane.

[0007] Furthermore, the laser printing annular spot system also includes a beam expander, which is arranged between the laser and the conical mirror.

[0008] Furthermore, the cone mirror is a circular convex cone mirror.

[0009] Furthermore, the axle is a circular concave axle.

[0010] Furthermore, the laser printing annular spot system also includes a switching device, which is provided with at least two axles, and each axle has a different refraction angle, and the switching device is used to switch different axles to be located on the path of the laser.

[0011] Furthermore, the switching device is used to drive the conical mirror to translate or rotate to switch to the path of the laser.

[0012] Furthermore, the field lens is an F-Theta field lens.

[0013] The above one or more technical solutions in the laser printing annular spot system provided by the embodiment of the present invention have at least the following technical effects:

[0014] The laser beam emitted by the laser passes through the collimator to form a parallel beam, and then is refracted by the axle mirror to diffuse outward in a ring-shaped cone or gathered in a cone shape, and then reflected by the galvanometer system and penetrates the field lens. After passing through the field lens, a ring-shaped light spot is formed on a working plane; thus meeting the needs of actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, 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 labor.

[0016] Figure 1 A schematic diagram of an embodiment of a laser printing annular spot system provided in an embodiment of the present invention.

[0017] Figure 2 A schematic diagram showing that the cone mirror of the laser printing annular spot system provided in an embodiment of the present invention is a concave mirror.

[0018] Figure 3 A schematic diagram of a laser printing annular spot system provided in an embodiment of the present invention having a switching device.

[0019] Figure 4 Schematic diagram of an annular spot formed by a laser printing annular spot system provided in an embodiment of the present invention.

[0020] Figure 5 A schematic diagram of a cross-sectional optical path of a laser printing annular spot system provided in an embodiment of the present invention in which the cone mirror is a convex mirror.

[0021] Figure 6 A schematic diagram of a cross-sectional optical path of a concave mirror formed by the laser printing annular spot system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0023] In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0025] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0026] In one embodiment of the laser 3D printing device of the present invention, please refer to Figures 1 to 4 , the laser 3D printing device includes a laser printing annular spot system. The laser printing annular spot system includes a laser 100, a collimator, a conical mirror 200, a galvanometer system 300 and a field lens 400. The laser beam emitted by the laser 100 forms a parallel beam after passing through the collimator, and the parallel beam is refracted by the conical mirror 200 to form a laser beam that diffuses outward in a ring cone or converges in a cone. The refracted laser beam forms an annular spot or a converged spot on the galvanometer system 300. Specifically, it can be understood that the light beam emitted by the laser 100 forms a parallel beam after passing through the collimator, and the parallel beam can be understood as several groups of parallel beams after being refracted by the conical mirror 200, or it can be understood as forming two groups of parallel beams on the cross section of the conical mirror 200. Therefore, the parallel beams formed by all cross sections around the central axis are cone-shaped with the axial axis of the conical mirror 200 as an outer contour. For details, refer to Figure 5 and Figure 6 After being reflected by the galvanometer system 300, the light beam is still a light beam with an outer contour similar to a cone. Therefore, after being refracted by the axle mirror 200, the light beam is reflected by the galvanometer system 300 and then penetrates the field lens 400, so that the field lens 400 refracts the light beam with an outer contour of a cone, thereby forming a ring-shaped focusing spot 10 on a working plane 1, meeting the needs of actual production.

[0027] Further, refer to Figures 1 to 3 The laser printing annular spot system further includes a beam expander 500, which is disposed between the laser 100 and the axle mirror 200. The laser beam emitted by the laser 100 forms a light beam after passing through the beam expander 500.

[0028] Further, refer to Figure 1 The axle 200 is a circular convex axle. The axle 200 refracts the light beam of the laser 100 into a concentrated conical light beam, and the concentrated conical light beam forms a ring-shaped light spot on the working plane 1 after being refracted by the field lens.

[0029] Further, another embodiment of the axicon 200, specifically, referring to Figure 2, the cone mirror 200 may be a circular concave cone mirror. In this embodiment, the light beam emitted by the laser 100 diffuses outward in a ring shape after passing through the concave lens, thereby forming a cone-shaped light beam that diffuses outward. The annular diffused light beam is reflected by the galvanometer system 300 and then passes through the field lens 400, and the field lens 400 converges the diffused light beam into an annular light spot on a plane.

[0030] Furthermore, the field lens 400 is an F-Theta field lens. Specifically, under the conditions determined by the F-Theta field lens, the size of the light spot depends on the refraction angle of the axicon 200. The larger the refraction angle, the larger the annular light spot formed.

[0031] Furthermore, the laser printing annular spot system also includes a switching device 600, which is specifically referred to as Figure 3 The switching device 600 is provided with at least two axicons 200, and each axicon 200 has a different refractive angle. The switching device 600 is used to switch different axicons 200 to be located on the path of the laser 100. By switching axicons 200 with different refractive indices, the size of the annular light spot is switched. For example, a larger annular light spot is used to achieve rough printing, and a smaller annular light spot is used to achieve precise printing.

[0032] Furthermore, the switching device 500 is used to drive the axle mirror 200 to translate or rotate to switch to the path of the laser 100 .

[0033] Furthermore, the light beam emitted by the laser 100 may be converted into a ring-shaped parallel light beam by a beam shaping system.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser printing annular spot system, characterized in that: It includes a laser, a collimator, a cone mirror, a galvanometer system and a field mirror; the laser beam emitted by the laser is formed into a parallel beam by the collimator, and then refracted by the cone mirror to form a laser beam that diffuses outward in an annular cone or converges in a cone; the laser beam is reflected by the galvanometer system and penetrates the field mirror to form an annular light spot on a plane.

2. The laser printing annular spot system according to claim 1, characterized in that: It also includes a beam expander, which is arranged between the laser and the axicon.

3. The laser printing annular spot system according to claim 1, characterized in that: The cone mirror is a circular convex cone mirror.

4. The laser printing annular spot system according to claim 1, characterized in that: The axle is a circular concave axle.

5. The laser printing annular spot system according to claim 1, characterized in that: It also includes a switching device, which is provided with at least two axles, and each axle has a different refraction angle, and the switching device is used to switch different axles to be located on the path of the laser.

6. The laser printing annular spot system according to claim 6, characterized in that: The switching device is used to drive the conical mirror to translate or rotate and switch to the path of the laser.

7. The laser printing annular spot system according to claim 1, characterized in that: The field lens is an F-Theta field lens.

8. A laser 3D printing device, characterized in that: The invention comprises the laser printing annular spot system as described in any one of claims 1 to 7.

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