Laser heating assisted milling optical path

Abstract

The present invention belongs to the field of precision optical instrument technology, specifically an optical path specifically designed for laser heating-assisted milling, comprising a laser beam, a collimating lens assembly, a plane reflector, a linear beam expander assembly, and a reflector assembly. The laser beam passes through the collimating lens assembly to collimate the laser beam, is reflected by the plane reflector, enters the linear beam expander assembly to expand the collimated beam into a linear shape, and then is bent by the reflector assembly into a linear laser spot before being directed onto the surface of the workpiece to be machined. By adopting the above-mentioned technical solution, the resulting arc-shaped laser beam can better match the shape of the milling cutter, has a heating effect superior to that of traditional laser beams, and helps to improve the efficiency of laser heating-assisted milling.

Description

Technical Field

[0001] The invention belongs to the technical field of precision optical instruments, and in particular relates to a laser heating assisted milling optical path. Background Art

[0002] Laser heat-assisted milling involves irradiating the workpiece's processing area with a high-power laser beam at a specific time before milling. The material absorbs the light energy and heats up. When the temperature reaches a certain level, the material's milling characteristics change. Milling at this temperature softens the material, reducing cutting forces. The increased toughness of the material also reduces chipping and burring during milling, improving machining quality. Therefore, laser-assisted milling can reduce machining difficulty and cost while achieving better results.

[0003] By examining the relevant patents of laser heating assisted milling systems, it can be seen that the current research on laser heating assisted systems in relevant patents is mainly focused on the improvement of device structure and functional modules, and there is relatively little optimization of the laser light path. In traditional laser-assisted processing, when softening the material, the laser beam simply directly irradiates the processing surface. Because the laser energy distribution is Gaussian, its energy distribution within the spot is not uniform. This will cause uneven softening of the material due to the uneven illumination of the laser spot. In addition, the shape of the milling cutter is generally cylindrical, and it rotates and advances forward during processing. The circular laser spot cannot wrap the outer area of ​​the milling cutter well to heat the material in the forward direction of the milling cutter, thereby failing to effectively reduce the burrs remaining on the surface after processing, and the processing quality is difficult to continue to improve.

[0004] Therefore, research on dedicated laser optical paths will help further improve the laser-assisted heating effect, thereby further improving the quality of material processing and filling the gap in this research field. Summary of the Invention

[0005] The present invention provides an optical path for a laser heating-assisted milling system, which is used to solve the problems of a traditional laser heating-assisted system, such as uneven heating due to a circular light spot, and difficulty in further improving the processing effect due to a low matching degree between the light spot shape and the milling cutter shape.

[0006] In order to solve the above problems, the present invention proposes an optical path of a laser heating-assisted milling system, including a collimating mirror group part connected to a laser to collimate the laser, a beam expanding mirror group part for expanding the collimated light beam in a line shape, and a reflecting mirror group part for bending the line-shaped laser spot. The laser beam passes through the collimating mirror group to collimate the laser, is reflected by a plane reflecting mirror, enters the line-shaped beam expanding mirror group part to expand the collimated light beam in a line shape, and then bends the line-shaped laser spot through the reflecting mirror group to reach the surface of the workpiece to be processed.

[0007] The light beam received by the collimating lens group is a laser output light beam, which has a certain divergence angle and a Gaussian energy distribution.

[0008] The laser heating assisted milling optical path further includes a plane reflecting mirror for changing the direction of the optical path.

[0009] As a further solution of the present invention, the collimating lens group is a combination of positive and negative lenses or a doublet lens, and the surface shape of both lenses is a spherical lens.

[0010] As a further solution of the present invention, the inline beam expander assembly is a Powell prism, the curvature radius and cone coefficient of which are adjustable to facilitate changing the size of the light spot.

[0011] As a further solution of the present invention, the distance between the collimator group and the reflector group is adjustable to facilitate control of the light spot shape. Here, the main thing is to control the direction of the light spot bending, because the outgoing light will converge once, and the direction of the light spot is different before and after convergence, and the light spot size can also be changed.

[0012] As a further solution of the present invention, the reflector group is a frustum-shaped reflector, the generatrix direction of which should be perpendicular to the line-shaped light beam formed by the line-shaped beam expander group, and has a certain inclination angle with the propagation direction of the light. The position of the reflector can be moved along the axis direction of the frustum-shaped reflector to change the radius of the frustum of the concave surface of the area irradiated by the line-shaped laser beam, thereby adjusting the curvature radius of the light spot irradiated on the workpiece.

[0013] As a further solution of the present invention, the linear light beam is reflected by the reflector group and irradiated onto the surface of the workpiece to be processed to form a light spot, which has an arc shape.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] In terms of laser heating-assisted milling, the present invention has significant advantages. Through the cooperation of the collimating lens group, the straight-line beam expander group, and the reflector group, a laser beam with a certain divergence angle and a Gaussian energy distribution can be converted into a circular arc-shaped light spot with uniform energy distribution. The size and curvature radius of the light spot are adjustable, and it can effectively cooperate with the milling cutters of various milling systems to work, thereby extending the life of the milling cutter and improving processing efficiency and quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the optical path structure of laser heating-assisted milling according to an embodiment of the present invention.

[0017] Figure 2 This is a 3D rendering of a laser heating assisted milling optical path structure according to an embodiment of the present invention.

[0018] Figure 3 The figure is a partial structural diagram of a collimating lens assembly for a laser heating assisted milling optical path according to an embodiment of the present invention.

[0019] Figure 4 The present invention is a partial structural diagram of a straight-line beam expander assembly for laser heating-assisted milling optical paths according to an embodiment of the present invention.

[0020] Figure 5 The figure is a partial structural diagram of a reflector assembly for a laser heating assisted milling optical path according to an embodiment of the present invention.

[0021] Figure 6 This is a light spot array diagram of a laser heating assisted milling light path according to an embodiment of the present invention.

[0022] Figure 7 This is a relative illumination distribution diagram of a light spot in a laser heating-assisted milling light path according to an embodiment of the present invention.

[0023] In the accompanying drawings, the objects, structures, or components represented by each reference numeral are described as follows:

[0024] Incident Gaussian beam 1, collimating lens group 2, plane reflector 3, straight line beam expander group 4, frustum reflector 5, final workpiece surface to be processed 6, positive lens 7, negative lens 8, Powell prism top prism 9. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0026] See also Figure 1 According to an embodiment of the present invention, a laser heating assisted milling optical path includes a collimating mirror group part 2 connected to a laser to collimate the laser, a beam expanding mirror group part 4 for expanding the collimated light beam in a straight line, and a reflecting mirror group part 5 for bending the straight line.

[0027] The light beam received by the collimating lens group is the laser output light beam 1, which has a wavelength of 1070 nm, a divergence angle of 14°, and a Gaussian energy distribution.

[0028] The laser heating assisted milling optical path also includes a plane reflector 3 for changing the direction of the optical path. The plane reflector 3 is placed at an angle of 45° to the optical path to adjust the overall optical path structure and reserve space for the milling cutter.

[0029] See also Figure 3 The collimating lens group 2 includes a positive lens 7 and a negative lens 8, both of which are spherical mirrors. The divergence angle of the collimated beam is 0.022mrad, and the collimation effect is excellent.

[0030] See also Figure 4 The straight line beam expander group 4 is a Powell prism, and its top edge 9 is arc-shaped. When the light passes through the top of the arc, it will be refracted and thus dispersed into a straight line beam. The curvature radius and cone coefficient of the top edge 9 are adjustable.

[0031] By adjusting the distance between the linear beam expander group 4 and the reflector group 5 , the size of the final light spot can be controlled.

[0032] See also Figure 5 The reflector 5 is a frustum-top reflector, the generatrix direction of which should be perpendicular to the line-shaped light beam formed by the line-shaped beam expander group, and has a certain inclination angle with the propagation direction of the light.

[0033] See also Figure 6 The linear light beam is reflected by the reflector 5 and irradiated onto the surface of the workpiece to be processed to form a light spot, which is in the shape of an arc.

[0034] See also Figure 7 The arc-shaped light spot formed on the surface of the workpiece has excellent energy distribution uniformity, which can wrap the milling cutter and evenly heat the area to be processed in front of the milling cutter.

[0035] In practical applications, the divergence angle of the light beam 1 emitted by the fiber laser is reduced after passing through the collimating lens group 2, but the collimated laser is still a Gaussian beam, and its energy is mainly concentrated in the center of the beam. The Powell prism 5 can redistribute the beam to form a straight line beam with uniform light density, good stability and good linearity.

[0036] The Powell prism 5 has a curved surface in front and a flat surface in the back. The shape of its front surface 9 is primarily adjusted by two parameters: the radius of curvature and the conic coefficient. As the radius of curvature increases, the beam divergence angle decreases, and the line width on the image plane at the same position also decreases. As the conic coefficient increases, the energy distribution becomes more concentrated toward the center of the line. By controlling these two parameters, the divergence angle and energy distribution of the line beam can be flexibly controlled.

[0037] After being reflected by the reflective cone 5, the linear beam converges. The workpiece to be processed should be placed in front of the converging surface to ensure that the arc-shaped light spot bends outward, thereby better matching the milling cutter located on the outside. The curvature radius of the reflective cone can also be adjusted to match different milling cutters.

[0038] The present invention uses a collimating lens set to collimate the divergent laser beam into a parallel beam. A linear beam expander set then shapes the parallel laser beam into a linear laser beam. Finally, a reflector transforms the linear laser beam into an arc-shaped beam, creating an arc-shaped spot on the workpiece. Analysis confirms that the resulting arc-shaped laser beam better matches the shape of the milling cutter, resulting in a superior heating effect compared to traditional laser beams, helping to improve the efficiency of laser heating-assisted milling.

[0039] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative use of these terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0040] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made based on the contents of this specification. For example, by adjusting the distance between the reflective frustum reflector 5 and the Powell prism 4, light spots of various sizes can be formed, and different milling cutters can be matched. These modifications and changes greatly enhance the universality of the optical system described in the present invention. Therefore, this specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can better understand and utilize the present invention.

[0041] The technical principles of the present invention have been described above in conjunction with specific embodiments, which are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All principles and technical solutions that fall within the scope of protection of the present invention are also within the scope of protection of the present invention. All other specific embodiments and technical principles of the present invention that can be associated with the present invention without inventive effort are also within the scope of protection of the present invention.

Claims

1. A laser heating assisted milling optical path, characterized by: It comprises a laser beam (1), a collimating lens group (2), a plane reflector (3), a straight line beam expander group (4) and a reflector group (5), wherein: The light beam received by the collimating lens group (2) is a laser light beam (1) emitted by a fiber laser, which has a certain divergence angle and a Gaussian energy distribution; The collimating lens group (2) comprises a positive lens and a negative lens, which are used to connect the laser beam (1), and the positive lens and the negative lens are both spherical lenses; the collimating lens group (2) is a double cemented lens; The plane reflector (3) is placed between the collimating lens group (2) and the straight line beam expander group (4), and the angle between the placement direction and the optical path is 45 degrees; The straight line beam expander lens assembly (4) is a Powell prism, the top edge of which is arc-shaped, the tail end is flat, and the top end faces the plane reflector (3); The reflector group (5) is a frustum-top reflector, and the light reflected from the reflector is irradiated onto the surface of the workpiece to be processed (6), with the generatrix direction being perpendicular to the line-shaped light beam formed by the line-shaped beam expander group and forming a certain inclination angle with the propagation direction of the light; The laser beam (1) passes through the collimating lens group (2) to collimate the laser beam, is reflected by the plane reflector (3), enters the line beam expanding lens group (4) to expand the collimated beam in a line shape, and then passes through the reflector group (5) to bend the line-shaped laser spot and arrive at the surface (6) of the workpiece to be processed.

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