High-precision closed-loop focusing device for laser cladding with in-light coaxial powder feeding

Abstract

The utility model relates to laser cladding technical field, proposed light is in the coaxial powder feeding's laser cladding high accuracy closed -loop focusing device, including the cover head casing, the inside fixed connection of cover head casing has two parallelly arranged linear guide rails, the sliding connection of two linear guide rails has the sliding block, the bottom of sliding block is provided with the lens mount, the fixed plate on the bottom of sliding block is fixedly connected in lens mount, the inside of lens mount is provided with zoom lens group, the bottom of cover head casing is provided with the laser channel of the concentric setting with zoom lens group, the outside of cover head casing is provided with four powder feeding channels, four powder feeding channels surround laser channel and angle distribution, one end of lens mount is provided with the drive module for drive lens mount vertical activity. The utility model discloses through the transmission combination of ''stepping motor + ball screw + linear guide rail '' and laser displacement sensor closed loop feedback, positioning accuracy greatly promotes.

Description

Technical Field

[0001] This utility model relates to the field of laser cladding technology, specifically to a high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical system. Background Technology

[0002] In laser cladding technology, the stability of the focal point directly determines the forming quality of the cladding layer (such as thickness uniformity and bonding strength). Traditional laser cladding focusing systems mostly use manual adjustment or open-loop electric adjustment: manual adjustment relies on the operator's experience, is inefficient and has poor accuracy (positioning error is often >0.05mm); although open-loop electric adjustment does not require manual intervention, due to problems such as transmission gaps and component wear, it is difficult to compensate for focal point shifts caused by workpiece surface undulations or mechanical vibrations in real time, which easily leads to defects such as over-melting / incomplete melting of the cladding layer.

[0003] Especially in optical coaxial powder delivery scenarios, the compatibility issues of existing focusing systems are more pronounced. Optical coaxial powder delivery requires meeting the core structural requirement of a "hollow laser beam surrounding the central powder delivery channel." However, the lens mount movement trajectory and laser channel layout of traditional focusing systems often cause mechanical interference with the powder delivery channel. Some powder delivery channels, being close to the lens adjustment area, are easily scratched by the moving mount. More importantly, traditional systems lack precise control over "laser-powder coaxiality." The deviation between the powder delivery channel outlet and the central axis of the hollow laser beam is often greater than 0.5mm, causing the powder flow to fail to fully enter the laser energy focusing area. This results in problems such as "premature powder melting and clumping" or "misalignment between the focus and the powder flow leading to insufficient cladding," severely affecting the cladding efficiency and quality stability of optical coaxial powder delivery. Therefore, a laser cladding focusing system specifically adapted for optical coaxial powder delivery needs to be designed to solve the problems of low precision, slow response, and poor compatibility with the optical coaxial powder delivery structure of traditional systems. Utility Model Content

[0004] This invention proposes a high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis, which solves the problem of inaccurate focal length control in the prior art.

[0005] The technical solution of this utility model is as follows: A high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis includes a cover housing. Two parallel linear guide rails are fixedly connected to the inner side of the cover housing. A slider is slidably connected between the two linear guide rails. A lens mounting base is provided at the bottom of the slider. The lens mounting base is fixedly connected to a fixing plate at the bottom of the slider. A variable zoom lens group is provided inside the lens mounting base. A laser channel concentrically arranged with the variable zoom lens group is opened at the bottom end of the cover housing. Four powder feeding channels are opened along the outer edge of the inner side of the cover housing. The four powder feeding channels are distributed at equal angles around the laser channel. A drive module for driving the vertical movement of the lens mounting base is provided at one end of the lens mounting base.

[0006] Preferably, the drive module includes a stepper motor fixedly mounted on the back side of the head cover housing, a motor driver fixedly connected to the outside of the stepper motor, the output end of the motor driver being electrically connected to the stepper motor, a coupling fixedly connected to the output shaft of the stepper motor, a lead screw fixedly connected to the end of the coupling away from the output shaft of the stepper motor, a threaded sleeve threadedly connected to the lead screw, and one end of the threaded sleeve being rigidly fixed to the lens mounting base.

[0007] Preferably, the zoom lens assembly includes a negative lens and a positive lens fixedly connected to both ends of the inner side of the lens mount, with the positive lens located below the negative lens.

[0008] Preferably, the negative lens and the positive lens are arranged coaxially, with an initial distance of 50 mm between them and an adjustment range of 30-100 mm.

[0009] Preferably, the negative lens is a concave lens and the positive lens is a convex lens.

[0010] Preferably, a laser displacement sensor is fixedly connected to the outside of the lens mounting base, the laser displacement sensor is signal-connected to a control system, the control system is electrically connected to a human-machine interface, and the motor driver is electrically connected to the control system.

[0011] Preferably, the rear ends of the four powder feeding channels are fixed to the inner wall of the head housing via flanges. The curved sections of the four powder feeding channels are located radially outward of the lens mounting base with a spacing of ≥10mm, completely avoiding the lens focusing stroke. The front exit ends of the four powder feeding channels are contracted into the hollow area of ​​the hollow laser beam, and the coaxiality between the exit center and the hollow axis of the laser beam is ≤0.2mm, ensuring that the powder is uniformly wrapped and heated when it is delivered from the center of the laser beam.

[0012] The working principle and beneficial effects of this utility model are as follows: 1. Significantly improved accuracy and stability of powder feeding within the optical system: Through the transmission combination of "stepper motor + ball screw + linear guide" and closed-loop feedback of laser displacement sensor, the positioning accuracy reaches ±0.005mm, which is greatly improved compared with the traditional system; the response time is shortened, and the focus shift caused by workpiece undulation can be compensated in real time. Combined with the coaxiality control of powder feeding channel and laser axis ≤0.2mm, the uniformity error of cladding layer thickness is ≤0.02mm, solving the problem of "powder-laser misalignment" in powder feeding within the optical system.

[0013] 2. Completely optimized compatibility of in-optical powder feeding: The powder feeding channel adopts a "surrounding laser channel + radial avoidance lens" layout, with a distance of ≥10mm between it and the lens mounting base, and no mechanical interference; the outlet end is located in the hollow area of ​​the hollow laser beam, and the powder flow is uniformly wrapped by the laser, avoiding the defects of "powder premature melting and clumping" or "insufficient cladding" in traditional systems, and improving the stability of in-optical powder feeding.

[0014] 3. Significantly improved efficiency of in-light cladding operation: The human-machine interface enables automated focusing without manual intervention, reducing the single focusing time from 5-10 minutes in the traditional manual mode to <10 seconds; and can display key parameters such as focus position and coaxiality deviation in real time, reducing the reliance on operator experience for in-light powder feeding, and increasing production efficiency by more than 5 times.

[0015] 4. Strong structural versatility and practicality: There are no patent restrictions on each component, and it can be independently produced and assembled; the focal length adjustment range is 50-300mm, which is suitable for most optical coaxial powder feeding and cladding scenarios (such as shaft repair, mold reinforcement, etc.), and the applicable laser wavelength and power range can be expanded by changing the lens group, making it widely applicable. Attached Figure Description

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0017] Figure 1 is a schematic diagram of the structure of the high-precision closed-loop focusing device for laser cladding with optical coaxial powder feeding according to this utility model. Figure 2 is a schematic diagram of the drive module structure of this utility model; Figure 3 is a schematic diagram of the optical path of this utility model; Figure 4 is a system block diagram of this utility model.

[0018] In the diagram: 1. Stepper motor; 2. Motor driver; 3. Coupling; 4-1. Lead screw; 4-2. Threaded sleeve; 5. Linear guide rail; 5-1. Slider; 6. Lens mount; 7. Variable zoom lens group; 7-1. Negative lens; 7-2. Positive lens; 8. Laser displacement sensor; 9. Control system; 10. Human-machine interface; 11. Laser channel; 12. Powder feeding channel; 13. Head cover housing. Detailed Implementation

[0019] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this utility model.

[0020] As shown in Figures 1 to 4, this embodiment proposes a high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis. It includes a cover housing 13, with two parallel linear guide rails 5 fixedly connected to the inner side of the cover housing 13. A slider 5-1 is slidably connected between the two linear guide rails 5. A lens mounting base 6 is located at the bottom of the slider 5-1 and is fixedly connected to a fixing plate at the bottom of the slider 5-1. A variable-focus lens group 7 is located inside the lens mounting base 6. A laser channel 11, concentrically arranged with the variable-focus lens group 7, is opened at the bottom end of the cover housing 13. Four powder feeding channels 12 are opened along the outer edge of the inner side of the cover housing 13, and are distributed at equal angles around the laser channel 11. A drive module for driving the vertical movement of the lens mounting base 6 is provided at one end of the lens mounting base 6.

[0021] Furthermore, the drive module includes a stepper motor 1 fixedly mounted on the back side of the head cover housing 13. A motor driver 2 is fixedly connected to the outside of the stepper motor 1. The output end of the motor driver 2 is electrically connected to the stepper motor 1. A coupling 3 is fixedly connected to the output shaft of the stepper motor 1. A lead screw 4-1 is fixedly connected to the end of the coupling 3 away from the output shaft of the stepper motor 1. A threaded sleeve 4-2 is threadedly connected to the lead screw 4-1. One end of the threaded sleeve 4-2 is rigidly fixed to the lens mounting base 6.

[0022] Furthermore, the zoom lens group 7 includes a negative lens 7-1 and a positive lens 7-2 fixedly connected to both ends of the inner side of the lens mount 6. The positive lens 7-2 is located below the negative lens 7-1. The negative lens 7-1 is a concave lens, and the positive lens 7-2 is a convex lens. The negative lens 7-1 and the positive lens 7-2 are arranged coaxially, with an initial distance of 50mm between them and an adjustment range of 30-100mm. Furthermore, a laser displacement sensor 8 is fixedly connected to the outside of the lens mounting base 6. The laser displacement sensor 8 is signal-connected to the control system 9. The control system 9 is electrically connected to the human-machine interface 10. The motor driver 2 is electrically connected to the control system 9.

[0023] The control system 9 is connected to the motor driver 2 via an RS485 interface, and outputs pulses and direction signals to control the stepper motor 1; the driver is powered by 24V, has a maximum output current of 3A, and supports 16 microsteps (step angle 0.01125°).

[0024] The laser displacement sensor 8 is connected to the control system 9 via an analog interface (4-20mA) with a sampling frequency of 1kHz to ensure real-time feedback of position data.

[0025] The human-machine interface 10 is integrated into the control system panel, which allows input of target focal length (corresponding to lens position), adjustment speed (0.1-5mm / s), and displays parameters such as current position and deviation value.

[0026] Furthermore, the rear ends of the four powder feeding channels 12 are fixed to the inner wall of the head housing 13 via flanges (away from the drive module to avoid interference with the motor); the curved sections in the middle of the four powder feeding channels 12 are located radially outward of the lens mounting base 6 with a spacing of ≥10mm, completely avoiding the lens focusing stroke; the front exit ends of the four powder feeding channels 12 are contracted into the hollow area of ​​the hollow laser beam and the coaxiality between the exit center and the hollow axis of the laser is ≤0.2mm, ensuring that the powder is uniformly wrapped and heated when it is delivered from the center of the laser beam.

[0027] Working principle: Initialization: After the system starts, the control system 9 drives the stepper motor 1 to move the lens mounting base 6 to the mechanical origin (the position with the maximum distance between the lens groups), and the laser displacement sensor 8 records the initial position (set to 0mm) to complete the calibration; Focusing operation: The operator inputs the target focal length (e.g., 80mm, corresponding to a lens position of 20mm) through the human-machine interface 10, the control system calculates the deviation (20mm - current position), drives the stepper motor 1 to rotate forward / reverse, and drives the lens to move along the guide rail 5 through the lead screw 4; Closed-loop adjustment: During the movement, the laser displacement sensor 8 provides real-time position feedback, and the control system 9 compares it with the target value. If the deviation is >0.005mm, it outputs a fine-tuning pulse (e.g., if the deviation is 0.01mm, it adds 2 pulses) until the deviation is ≤0.005mm, at which point the adjustment stops. Real-time compensation: During the cladding process, if the workpiece surface undulations cause the focus to shift (e.g., the sensor detects an abnormal change in lens position > 0.01mm), the control system automatically repeats step 3 to adjust the lens position in real time to ensure focus stability. Through the above structure and solution, the system can achieve a focus adjustment range of 50-300mm, a positioning accuracy of ±0.005mm, and a response time of <0.1s, meeting the high-precision control requirements of laser cladding focus. Moreover, there are no patent restrictions on the components, and they can be independently produced and assembled.

[0028] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A high-precision closed-loop focusing device for laser cladding with coaxial powder feeding, comprising a cladding shell (13), wherein two parallel linear guide rails (5) are fixedly connected to the inner side of the cladding shell (13), and a slider (5-1) is slidably connected between the two linear guide rails (5), characterized in that, The bottom of the slider (5-1) is provided with a lens mounting base (6), which is fixedly connected to the fixing plate at the bottom of the slider (5-1). A variable zoom lens group (7) is provided on the inner side of the lens mounting base (6). A laser channel (11) is provided at the bottom end of the cover housing (13) and is concentrically arranged with the variable zoom lens group (7). Four powder feeding channels (12) are provided on the outer edge of the inner side of the cover housing (13). The four powder feeding channels (12) are distributed at equal angles around the laser channel (11). A drive module for driving the lens mounting base (6) to move vertically is provided at one end of the lens mounting base (6).

2. The high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis according to claim 1, characterized in that, The drive module includes a stepper motor (1) fixedly installed on the back side of the head cover (13). A motor driver (2) is fixedly connected to the outside of the stepper motor (1). The output end of the motor driver (2) is electrically connected to the stepper motor (1). A coupling (3) is fixedly connected to the output shaft of the stepper motor (1). A lead screw (4-1) is fixedly connected to one end of the coupling (3) away from the output shaft of the stepper motor (1). A threaded sleeve (4-2) is threaded onto the lead screw (4-1). One end of the threaded sleeve (4-2) is rigidly fixed to the lens mounting base (6).

3. The high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis according to claim 1, characterized in that, The zoom lens group (7) includes a negative lens (7-1) and a positive lens (7-2) fixedly connected to both ends of the inner side of the lens mount (6), with the positive lens (7-2) located below the negative lens (7-1).

4. The high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis according to claim 3, characterized in that, The negative lens (7-1) and the positive lens (7-2) are arranged coaxially. The initial distance between the negative lens (7-1) and the positive lens (7-2) is 50mm, and the adjustment range is 30-100mm.

5. The high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis according to claim 3, characterized in that, The negative lens (7-1) is a concave lens, and the positive lens (7-2) is a convex lens.

6. The high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis according to claim 2, characterized in that, A laser displacement sensor (8) is fixedly connected to the outside of the lens mounting base (6). The laser displacement sensor (8) is connected to the control system (9). The control system (9) is electrically connected to the human-machine interface (10). The motor driver (2) is electrically connected to the control system (9).

7. The high-precision closed-loop focusing device for laser cladding with coaxial powder feeding within the optical axis according to claim 1, characterized in that, The rear ends of the four powder feeding channels (12) are fixed to the inner wall of the middle part of the head housing (13) by flanges. The middle curved section of the four powder feeding channels (12) is located on the radial outside of the lens mounting base (6). The front end of the four powder feeding channels (12) is contracted to the hollow area of ​​the hollow laser beam and the coaxiality between the outlet center and the hollow axis of the laser is ≤0.2mm, ensuring that the powder is uniformly wrapped and heated when it is sent out from the center of the laser beam.

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