Light spot detection and adjustment method and system

Abstract

The application discloses a light spot detection and adjustment method and system. The method comprises the following steps: in a printing process, a movable mirror is controlled to move into the light path of a printing laser, so that the printing laser focused by a field lens is reflected to a light spot detection unit through the movable mirror; an actual light spot size of the printing laser on a printing work surface detected by the light spot detection unit is acquired; the actual light spot size is compared with a preset reference light spot size, and a light spot size deviation is calculated; according to the light spot size deviation, an electrically-driven beam expander is controlled to adjust the divergence angle of the printing laser until the difference between the actual light spot size and the reference light spot size is within a preset range. The application can effectively compensate for the light spot size change caused by thermal drift, ensure the stability of the light spot size in a long-term printing process, and improve the 3D printing forming precision.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, specifically to a method and system for spot detection and adjustment. Background Technology

[0002] In laser additive manufacturing (such as selective laser melting), the size of the laser spot on the printed surface directly affects the forming accuracy and part quality. Ideally, the calibrated spot size should remain constant. However, during continuous printing, the laser and optical components (such as beam expanders and field lenses) are affected by thermal radiation and changes in ambient temperature, resulting in thermal expansion and refractive index drift. This causes the focal point of the optical path system to drift, thus causing the actual spot size on the printed surface to deviate from the initial set value.

[0003] Currently, some technologies attempt to monitor spot changes by detecting the incident beam at the front end of the optical path and adjust the beam expander accordingly to maintain spot stability. However, these methods cannot accurately reflect the actual state of the focused spot on the printed surface, and thermal drift of optical components such as field lenses during long-term operation can also affect the focused spot size, resulting in limited adjustment accuracy.

[0004] Therefore, overcoming the aforementioned environmental obstacles, achieving accurate detection of the focused spot on the printed surface, and performing closed-loop compensation of the entire optical path based on the detection results are technical problems that urgently need to be solved in this field. Summary of the Invention

[0005] This application provides a spot detection and adjustment method and system, which can solve the technical problems in the prior art that cannot accurately detect the actual focused spot on the printing surface and are difficult to compensate for the spot size change caused by thermal drift of the entire optical path, including the field lens.

[0006] In a first aspect, embodiments of this application provide a light spot detection and adjustment system, the light spot detection and adjustment system comprising: Laser, used to generate printing laser; An electric beam expander is disposed in the output beam path of the laser and is used to adjust the divergence angle of the printing laser; A scanning galvanometer is used to deflect the printing laser; A field lens is disposed in the output light path of the scanning galvanometer and is used to focus the printing laser onto the printing working surface; A movable reflector is disposed on the side of the optical path between the field lens and the printing working surface, and is configured with a detection position for moving into the optical path and a non-detection position for moving out of the optical path; A spot detection unit is disposed on the reflected light path of the movable reflector to receive the reflected printing laser and obtain the spot size; The controller is electrically connected to the drive mechanism of the motorized beam expander, the movable reflector, and the spot detection unit, respectively, and the controller is configured to perform the following method.

[0007] The system described above incorporates a movable reflector and a spot detection unit. During detection, the movable reflector moves into the optical path and reflects the focused printing laser light to the spot detection unit. Combined with a controller that uses a closed-loop control to adjust the laser divergence angle of the electric beam expander based on the deviation between the actual spot size and the reference spot size, the system achieves real-time, in-situ detection and automatic feedback adjustment of the actual focused spot on the printing surface. This effectively compensates for changes in spot size caused by thermal drift, ensuring the stability of the spot size and the forming accuracy during long-term printing.

[0008] In conjunction with the first aspect, in one embodiment, a drive mechanism is also included, the drive mechanism comprising a motor, a cylinder, or a linear module, for driving the movable reflector to switch between the detection position and the non-detection position.

[0009] In conjunction with the first aspect, in one embodiment, the movable reflector is a plane reflector, and the reflective surface of the plane reflector is coated with a high-reflectivity film that matches the wavelength of the printing laser.

[0010] In conjunction with the first aspect, in one embodiment, at the detection position, the vertical optical path length from the field lens to the printing surface is equal to the total optical path length from the field lens to the movable reflector and then to the spot detection unit.

[0011] In conjunction with the first aspect, in one embodiment, the light incident port of the light spot detection unit is provided with a dustproof protective window.

[0012] Secondly, embodiments of this application provide a method for detecting and adjusting a light spot, the method comprising: During the printing process, the movable reflector is controlled to move into the optical path of the printing laser so that the printing laser, after being focused by the field lens, is reflected by the movable reflector to the spot detection unit; The actual spot size of the printing laser on the printing surface is obtained by the spot detection unit. The actual spot size is compared with the preset reference spot size to calculate the spot size deviation; Based on the deviation in the spot size, the electric beam expander is controlled to adjust the divergence angle of the printing laser until the actual spot size recovers to within a preset range of the difference between it and the reference spot size.

[0013] In conjunction with the second aspect, in one embodiment, controlling the electric beam expander to adjust the divergence angle of the printing laser based on the spot size deviation includes: When the actual spot size is larger than the reference spot size, the motorized beam expander is controlled to increase the divergence angle of the printing laser; When the actual spot size is smaller than the reference spot size, the motorized beam expander is controlled to reduce the divergence angle of the printing laser.

[0014] The above method controls a movable reflector to move into the optical path so that the printing laser focused by the field lens is reflected to the spot detection unit, obtains the actual spot size and compares it with the reference spot size to calculate the deviation. Then, based on the deviation, the electric beam expander is controlled to adjust the divergence angle until the deviation is restored to the preset range. This achieves closed-loop feedback adjustment of the actual focused spot on the printing surface, thereby effectively compensating for the spot size change caused by thermal drift and ensuring the long-term stability of the spot size and the consistency of the forming during the printing process.

[0015] In conjunction with the second aspect, in one embodiment, the movable reflector moves into the optical path of the printing laser at a preset gap after each layer of printing is completed or during each layer of printing, and moves out of the optical path of the printing laser after detection is completed.

[0016] In conjunction with the second aspect, in one embodiment, the reference spot size is the spot size measured on the printing surface during the pre-printing debugging stage.

[0017] Thirdly, embodiments of this application provide a computer-readable storage medium storing a spot detection and adjustment program, wherein when the spot detection and adjustment program is executed by a processor, it implements the steps of the above-described spot detection and adjustment method.

[0018] The beneficial effects of the technical solutions provided in this application include: By setting a movable reflector to move into the optical path during detection, the printing laser focused by the field lens is reflected to the spot detection unit, realizing in-situ equivalent detection of the actual focused spot on the printing surface. This overcomes the technical obstacle of not being able to set up precision detection instruments for a long time in the high temperature and dusty environment of the printing area. At the same time, based on the deviation between the detected actual spot size and the reference value, the laser divergence angle is adjusted by the closed-loop control of the electric beam expander, which can effectively compensate for the spot size change caused by thermal drift of the entire optical path, including the field lens, so that the spot size remains stable in the long term, thereby significantly improving the forming accuracy and consistency of 3D printing. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the architecture of an embodiment of the spot detection and adjustment system of this application; Figure 2 This is a schematic flowchart of an embodiment of the spot detection and adjustment method of this application. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0022] In a first aspect, embodiments of this application provide a spot detection and adjustment system 00.

[0023] In one embodiment, reference is made to Figure 1 , Figure 1 This is a schematic diagram of the architecture of an embodiment of the light spot detection and adjustment system 00 of this application. Figure 1 As shown, the spot detection and adjustment system 00 includes: Laser 01: Used to generate printing laser.

[0024] In some embodiments, the output end of laser 01 may be connected to an optical fiber transmission cable. Laser 01 is preferably a fiber laser, and its output wavelength may be a continuous laser at 1064 nm.

[0025] Electric beam expander 02: Located in the output light path of laser 01, used to adjust the divergence angle of the printing laser.

[0026] In some embodiments, the motorized beam expander 02 integrates a stepper motor and a transmission mechanism, which can continuously adjust the beam expansion magnification under the command of the controller 08, thereby changing the divergence angle of the output laser. In this embodiment, the adjustment range of the motorized beam expander 02 can be from 1× to 8×, with an adjustment accuracy of 0.1× steps.

[0027] Scanning galvanometer 03: Located in the output light path of motorized beam expander 02, used to deflect the printing laser.

[0028] In some embodiments, the scanning galvanometer 03 includes an X-axis deflector and a Y-axis deflector, which are driven by high-speed servo motors and used to deflect the laser beam in the XY plane under the control of the controller 08 to realize the scanning path.

[0029] Field lens 04: Located in the output light path of scanning galvanometer 13, that is, below scanning galvanometer 03, it is used to focus the printing laser onto the printing working surface 06.

[0030] In some embodiments, the field lens 04 may be an f-theta lens with a focal length of F = 500 mm. The field lens 04 is used to focus the parallel or divergent laser beam emitted from the scanning galvanometer 03 onto the printing working surface 06 to form a focused spot for melting metal powder.

[0031] Movable reflector 05: Located on the side of the optical path between field mirror 04 and printing working surface 06, and configured with a detection position for moving into the optical path and a non-detection position for moving out of the optical path.

[0032] In some embodiments, the movable reflector 05 may be a planar reflector with a highly reflective coating (such as a metal-dielectric composite film with a reflectivity >99.5%) on its reflective surface that matches the printing laser wavelength (1064nm). The reflector 05 is connected to a drive mechanism via a telescopic arm. The drive mechanism may be a linear motor module, which can move the reflector 05 in a direction perpendicular to the optical axis, thereby giving the reflector 05 two working positions: Non-detection position: The reflector 05 is completely removed from the optical path (removed from the optical path of the printing laser), which does not affect the normal propagation of the printing laser, and the laser directly irradiates the printing working surface 06.

[0033] Detection position (i.e., measurement position): The reflector 05 moves into the optical path, located between the field lens 04 and the printing working surface 06, and forms a 45° angle with the optical axis. At this position, the laser beam emitted from the field lens 04 is deflected by the reflector 05 by 90° and then directed towards the spot detection unit.

[0034] In some embodiments, the detection position satisfies the following optical equidistance condition: the vertical optical path length from the field lens 04 to the printing working surface 06 (i.e., the working distance L1 of the field lens 04) is equal to the total optical path length from the field lens 04 to the movable reflector 05 and then to the spot detection unit 07 (i.e., the distance L2 from the field lens 04 to the reflector 05 plus the distance L3 from the reflector 05 to the receiving surface of the spot detection unit). Thus, the spot size formed by the laser beam on the receiving surface of the spot detection unit 07 is exactly the same as the actual focused spot size on the printing working surface 06, achieving in-situ equivalent detection.

[0035] Spot detection unit 07: is set on the reflected light path of movable reflector 05.

[0036] In some embodiments, the spot detection unit 07 may employ a CMOS camera (such as a Basler acA1300-60gm), with an attenuator and filter matching the printing laser wavelength mounted in front of the camera lens. The light entrance of the spot detection unit 07 is also equipped with a dustproof protective window made of infrared-transparent glass, which prevents metal dust and fumes generated during printing from entering the camera, extending the equipment's lifespan. The spot detection unit 07 is used to acquire images of the reflected laser spot and calculates the diameter or radius of the spot in real time using image processing algorithms (such as grayscale centroid method or Gaussian fitting method).

[0037] Controller 08: An industrial computer (PLC or embedded industrial computer) is used, which is electrically connected to the electric beam expander 02, the drive mechanism (telescopic arm motor), and the spot detection unit 07.

[0038] In some embodiments, the controller 08 integrates a storage unit for storing a reference spot size and a mapping table between the spot size deviation and the divergence angle adjustment. The controller 08 is configured to perform the following spot detection and adjustment method.

[0039] Before printing begins, during the debugging phase, the movable reflector 05 is moved to the detection position, and the spot detection unit 07 measures the initial spot size on the printing surface 06, storing this size as the reference spot size in the controller 08. Afterward, the movable reflector 05 returns to the non-detection position, and the actual printing begins.

[0040] During the printing process, the system performs spot detection and adjustment according to a preset detection frequency (e.g., after each layer is printed, or during the printing process when the galvanometer returns to zero gap). The specific steps are as follows: Moving the movable reflector 05: The controller 08 sends a command to the drive mechanism, and the telescopic arm moves the movable reflector 05 from the non-detection position to the detection position. The movement process takes about 0.2 seconds, and the position is confirmed by the position sensor.

[0041] Laser spot acquisition: After passing through the field lens 04, the printing laser is deflected by the reflector 05 and directed towards the laser spot detection unit 07. The laser spot detection unit 07 acquires the laser spot image and calculates the actual spot size (e.g., diameter D_real). Due to the equal optical path length design, D_real is the actual focused spot size on the current printing surface 06.

[0042] Calculate the deviation: Controller 08 reads the stored reference spot size D_ref and calculates the deviation ΔD = D_real -D_ref.

[0043] Feedback adjustment: If the absolute value of the deviation ΔD exceeds the preset allowable range (e.g., ±2μm), the controller 08 generates a control signal to drive the motorized beam expander 02 according to the sign and magnitude of the deviation. If the deviation ΔD>0 (actual spot size is too large), it indicates that the focal point has drifted above the printing surface 06 and the divergence angle is too large. The controller 08 increases the magnification of the electric beam expander 02, thereby increasing the divergence angle and reducing the actual spot size.

[0044] If the deviation ΔD < 0 (actual spot size is too small), it indicates that the focal point has drifted downwards towards the printing surface 06, and the divergence angle is too small. The controller 08 reduces the magnification of the electric beam expander 02, thereby reducing the divergence angle and increasing the actual spot size.

[0045] The adjustment amount is determined by a pre-calibrated proportional coefficient; for example, for every 1 μm change in ΔD, the beam expander 02 increments by one step. During the adjustment process, multiple measurements and iterative approximations can be performed until |ΔD| ≤ the allowable range.

[0046] Remove reflector 05: After adjustment, controller 08 will return the movable reflector 05 to the non-detection position, restore the normal propagation of the printing laser, and continue printing the next area or the next layer.

[0047] This embodiment achieves in-situ, non-contact, and equivalent measurement of the actual focused spot on the printing surface 06 by setting a movable reflector 05 and satisfying the condition of equal optical path length. This overcomes the difficulty of placing precision instruments in the high-temperature and dusty environment of the printing area for extended periods. Simultaneously, by controlling the electric beam expander 02 through closed-loop feedback, it can compensate for changes in spot size caused by thermal drift in real time, ensuring the stability of the spot size during long-term printing, thereby improving the forming accuracy and consistency of the parts.

[0048] In other embodiments, the drive mechanism can use a cylinder or linear module instead of a linear motor. The movement of the movable reflector 05 in / out can also be designed as a rotary swing-in type rather than a linear translation type, as long as it can achieve the switching between the detection position and the non-detection position. The spot detection unit 07 can use a CCD camera or a dedicated beam quality analyzer (such as DataRay WinCamD). The dustproof protective window can be used in conjunction with a positive air curtain (such as compressed air blowing) to further prevent dust adhesion.

[0049] Secondly, embodiments of this application also provide a method for spot detection and adjustment.

[0050] In one embodiment, reference is made to Figure 2 , Figure 2 This is a schematic flowchart of an embodiment of the spot detection and adjustment method of this application. Figure 2 As shown, the spot detection and adjustment method includes: Step S10: During the printing process, the movable reflector is controlled to move into the optical path of the printing laser so that the printing laser, after being focused by the field lens, is reflected by the movable reflector to the spot detection unit; In some embodiments, the reference spot size can be calibrated before starting the actual printing. The specific steps are as follows: A movable reflector is moved into the detection position in the optical path, causing the laser to output continuous laser light at a preset power (e.g., 200W). The laser beam passes through an electric beam expander and a scanning galvanometer before being incident on a field lens, which focuses the laser. The focused laser beam is then reflected by the movable reflector to the spot detection unit. Because the detection position satisfies the optical equidistant condition that the vertical optical path length from the field lens to the printing surface is equal to the total optical path length from the field lens to the reflector and then to the spot detection unit, the spot size received by the spot detection unit is equal to the actual focused spot size on the printing surface.

[0051] A spot detection unit (e.g., a CMOS camera) acquires a spot image, calculates the spot diameter using an image processing algorithm (e.g., Gaussian fitting), records this diameter as the reference spot size D0, and stores it in the controller's storage unit. After calibration, the movable reflector is moved out of the optical path, and the device enters the printing preparation state. In other embodiments, the controller can also calculate the spot diameter based on the spot image using an image processing algorithm.

[0052] Step S20: Obtain the actual spot size of the printing laser on the printing surface as detected by the spot detection unit; In some embodiments, spot detection is performed during the printing process according to a preset detection cycle. The detection cycle can be set according to the printing accuracy requirements and thermal drift rate, for example, once after each layer is printed, or during the interval (approximately 0.5 to 1 second) when the scanning galvanometer returns to zero during each layer printing process.

[0053] The specific procedures for each test are as follows: The controller sends a command to the drive mechanism of the movable mirror, which drives the telescopic arm to move the mirror from the non-detection position (outside the optical path) to the detection position (inside the optical path, located between the field lens and the printing working surface).

[0054] After the reflector is in place, the spot detection unit acquires the laser spot image at the current moment and calculates the current actual spot size D1 (unit: micrometers). In other embodiments, the controller can also calculate the actual spot size D1 based on the laser spot image at the current moment.

[0055] To prevent dust interference, the light entrance of the spot detection unit is equipped with a dustproof protective window. The detection process takes approximately 0.3 seconds, during which the printing laser continues to output, but the scanning galvanometer pauses its deflection to ensure spot stability.

[0056] Step S30: Compare the actual spot size with the preset reference spot size and calculate the spot size deviation; In some embodiments, the controller reads the reference spot size D0 calibrated in step S10 from the storage unit and calculates the deviation value ΔD = D1 – D0. At the same time, an allowable deviation range is set, for example, ±2μm (the specific threshold can be set according to the equipment accuracy and component requirements, generally between 1 and 5μm).

[0057] Step S40: Based on the spot size deviation, control the electric beam expander to adjust the divergence angle of the printing laser until the difference between the actual spot size and the reference spot size is within a preset range.

[0058] In some embodiments, the controller determines whether ΔD exceeds a preset range: If |ΔD| ≤ 2μm, the current spot size is considered to meet the requirements and no adjustment is needed. The controller directly issues a command to move the reflector out of the optical path and continue printing.

[0059] If |ΔD|>2μm, then feedback adjustment is considered necessary. The adjustment rules are as follows: When ΔD>0 (i.e., the actual spot size D1 is greater than the reference spot size D0), it indicates that the focal point has drifted upwards towards the printing surface, and the divergence angle of the current laser beam is too large. The controller controls the motorized beam expander to increase the beam expansion ratio (i.e., increase the divergence angle), thereby reducing the focused spot size.

[0060] When ΔD < 0 (i.e., the actual spot size D1 is smaller than the reference spot size D0), it indicates that the focal point has drifted downwards towards the printed surface, and the divergence angle of the current laser beam is too small. The controller controls the motorized beam expander to reduce the beam expansion ratio (i.e., reduce the divergence angle), thereby increasing the focused spot size.

[0061] The magnitude of the adjustment is related to the absolute value of the deviation. In this embodiment, the proportional relationship between the spot size deviation and the beam expander step size is pre-calibrated experimentally (e.g., for every 1 μm change in ΔD, the beam expander steps by 2 increments). The controller calculates the required number of steps based on the absolute value of the deviation and generates a drive signal to send to the stepper motor inside the motorized beam expander.

[0062] During the adjustment process, the closed-loop iteration of "detection-calculation-adjustment" can be repeated until |ΔD| falls back to the preset range (e.g., ≤2μm). Generally, one adjustment is sufficient to meet the requirements; if the deviation is large due to strong thermal shock, 2 to 3 iterations may be required.

[0063] In some embodiments, once the difference between the actual spot size and the reference spot size meets the requirements, the controller moves the movable reflector out of the optical path and resumes printing. The printing laser continues to scan along the preset path, and since the spot size has been restored to the reference value, the forming quality is guaranteed.

[0064] In some embodiments, the adjustment target can be "the difference between the actual spot size recovery and the reference spot size is within a preset range", rather than being exactly equal. For example, an error of ±1.5 μm can be allowed to avoid frequent adjustments affecting efficiency. At the same time, the adjustment rule for the spot size deviation can also adopt a proportional-integral-derivative (PID) control algorithm to achieve a smoother adjustment process.

[0065] Thirdly, embodiments of this application also provide a computer-readable storage medium.

[0066] The present application has a computer-readable storage medium storing a spot detection and adjustment program, wherein when the spot detection and adjustment program is executed by the processor 21, it implements the steps of the spot detection and adjustment method described above.

[0067] The method implemented when the spot detection and adjustment procedure is executed can be referred to in various embodiments of the spot detection and adjustment method of this application, and will not be repeated here.

[0068] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0069] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0070] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0071] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0072] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0073] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0074] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method of light spot detection and adjustment, characterized in that, The light spot detection and adjustment method includes: During the printing process, the movable reflector is controlled to move into the optical path of the printing laser so that the printing laser, after being focused by the field lens, is reflected by the movable reflector to the spot detection unit; The actual spot size of the printing laser on the printing surface is obtained by the spot detection unit. The actual spot size is compared with the preset reference spot size to calculate the spot size deviation; Based on the deviation in the spot size, the electric beam expander is controlled to adjust the divergence angle of the printing laser until the actual spot size recovers to within a preset range of the difference between it and the reference spot size.

2. The light spot detection and adjustment method of claim 1, wherein, The step of controlling the electric beam expander to adjust the divergence angle of the printing laser based on the spot size deviation includes: When the actual spot size is larger than the reference spot size, the motorized beam expander is controlled to increase the divergence angle of the printing laser; When the actual spot size is smaller than the reference spot size, the motorized beam expander is controlled to reduce the divergence angle of the printing laser.

3. The light spot detection and adjustment method of claim 1, wherein, The movable reflector moves into the optical path of the printing laser at a preset gap after each layer is printed or during each layer printing process, and moves out of the optical path of the printing laser after the detection is completed.

4. The light spot detection and adjustment method of claim 1, wherein, The reference spot size is the spot size measured on the printing surface during the pre-printing debugging stage.

5. A light spot detection and adjustment system, characterized in that The light spot detection and adjustment system includes: Laser, used to generate printing laser; An electric beam expander is disposed in the output beam path of the laser and is used to adjust the divergence angle of the printing laser; A scanning galvanometer is used to deflect the printing laser; A field lens is disposed in the output light path of the scanning galvanometer and is used to focus the printing laser onto the printing working surface; A movable reflector is disposed on the side of the optical path between the field lens and the printing working surface, and is configured with a detection position for moving into the optical path and a non-detection position for moving out of the optical path; A spot detection unit is disposed on the reflected light path of the movable reflector to receive the reflected printing laser and obtain the spot size; The controller is electrically connected to the drive mechanism of the electric beam expander, the movable reflector, and the spot detection unit, respectively, and the controller is configured to perform the method according to any one of claims 1-4.

6. The flare detection and adjustment system of claim 5, wherein, It also includes a drive mechanism, which includes a motor, cylinder or linear module, for driving the movable reflector to switch between the detection position and the non-detection position.

7. The flare detection and adjustment system of claim 5, wherein, The movable reflector is a plane reflector, and the reflective surface of the plane reflector is coated with a high-reflectivity film that matches the wavelength of the printing laser.

8. The flare detection and adjustment system of claim 5, wherein, At the detection position, the vertical optical path length from the field lens to the printing surface is equal to the total optical path length from the field lens to the movable reflector and then to the spot detection unit.

9. The flare detection and adjustment system of claim 5, wherein, The light incident port of the light spot detection unit is equipped with a dustproof protective window.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a spot detection and adjustment program, wherein when the spot detection and adjustment program is executed by a processor, it implements the steps of the spot detection and adjustment method as described in any one of claims 1 to 4.

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