High-speed dynamic focus tracking laser scanning system

Abstract

The invention relates to the technical field of laser processing, in particular to a high-speed dynamic focus tracking laser scanning system which comprises a dichroscope, a light beam zooming unit and a galvanometer unit which are sequentially arranged on a path of a laser beam, and a visual detection unit located outside the path. Wherein the light beam zooming unit is configured to be capable of focusing a laser beam and adjusting the focal length of the laser beam; the dichroscope is configured to allow the laser beam to pass through; the detection end of the visual detection unit is configured to be capable of obtaining an image of a printed piece formed on the printing plane through the dichroscope and the galvanometer unit. In the printing process, the image of the printed piece formed on the printing plane is reflected to the detection end of the visual detection unit through the galvanometer unit and the dichroscope, whether the formed printed piece deviates from the preset printing position or not can be recognized through the image obtained by the visual detection unit, and splicing dislocation can be monitored in real time in the printing process; and therefore, splicing correction can be conveniently carried out on a splicing dislocation position.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a high-speed dynamic focus tracking laser scanning system. Background Art

[0002] Laser 3D printing is the printing of three-dimensional objects through a laser scanning system. The basic process is: the powder feeding device delivers a certain amount of powder to the working platform surface, the powder spreading device spreads a layer of powder material on the bottom plate of the forming cylinder or the upper surface of the formed part, and the laser galvanometer system controls the laser to scan the solid part of the powder layer according to the cross-sectional contour of the layer with an approximately constant spot size and beam energy, so that the powder melts and bonds with the formed part below; when a layer of cross section is sintered, the working platform drops by one layer of thickness, and the powder spreading device spreads a layer of uniform and dense powder on it, and scans and sinters a new layer of cross section. After several layers of scanning and superposition, the entire three-dimensional object is manufactured.

[0003] At present, in order to achieve high efficiency and large format, multiple laser scanning systems are mainly used for simultaneous printing. Multiple laser scanning systems work simultaneously in their respective partitions during the forming process, and each partition is spliced ​​to form a complete printing pattern, which increases the forming size and forming efficiency of the equipment exponentially.

[0004] Although multiple scanning systems working together to print can improve efficiency, there are also some problems: First, the splicing of molded parts at the laser intersection is prone to misalignment in the XY direction. Currently, splicing correction is mainly performed before printing. However, even if splicing correction has been performed before printing, during the actual printing process, the galvanometer will still drift in the splicing position due to environmental changes such as temperature, humidity, vibration, and mechanical wear of the galvanometer motor, resulting in splicing misalignment; secondly, the light spot formed by the laser beam projected on the printing plane is easily offset in the Z-axis direction during the printing process due to environmental influences such as temperature and vibration or other influences, causing the focus to deviate from the printing plane. Summary of the invention

[0005] In view of the above-mentioned defects, the technical problem to be solved by the present invention is to provide a high-speed dynamic focus tracking laser scanning system, which can monitor the stitching deviation of the print during the printing process and perform real-time correction.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A high-speed dynamic tracking focus laser scanning system comprises a dichroic mirror, a beam zoom unit and a galvanometer unit which are sequentially arranged on the path of a laser beam, and a visual detection unit which is located outside the path;

[0008] The beam zoom unit is configured to focus the laser beam and adjust the focal length of the laser beam;

[0009] The galvanometer unit is configured to be capable of reflecting the laser beam to a printing plane, and capable of adjusting a plane position of the laser beam reflected to the printing plane;

[0010] The dichroic mirror is configured to allow the laser beam to pass through;

[0011] The detection end of the visual detection unit is configured to be able to obtain an image of the printed part formed on the printing plane through a dichroic mirror and a galvanometer unit.

[0012] By adopting the above scheme, when in use, the laser beam passes through the dichroic mirror and the beam zoom unit in sequence along the path to reach the galvanometer unit, the laser beam is focused by the beam zoom unit, and the position where the laser beam is reflected on the printing plane is adjusted by the galvanometer unit. The image of the printed part formed on the printing plane is reflected to the detection end of the visual detection unit through the galvanometer unit and the dichroic mirror. The data obtained by the detection end of the visual detection unit can identify whether the formed print part deviates from the preset printing position, and the splicing misalignment can be reflected, so that the splicing misalignment can be monitored in real time during the printing process. According to the information of splicing misalignment, before scanning and printing the next layer, the scanning path of the laser beam on the printing plane is adjusted by the galvanometer unit to perform splicing correction on the splicing misalignment. Among them, since the galvanometer unit adjusts the position of the laser beam reflected on the printing plane during the printing process, it scans along a preset path on the printing plane. During the scanning process, the galvanometer unit can reflect the image of the part being scanned and the adjacent part that has been scanned onto the dichroic mirror, and the dichroic mirror reflects it to the detection end of the visual detection unit, thereby being able to obtain in real time the molding condition of the printed part formed on the scanning path.

[0013] Preferably, the beam zoom unit includes a focusing lens group, a diverging mirror and a linear drive mechanism, the diverging mirror is fixed at the working end of the linear drive mechanism, the laser beam first passes through the diverging mirror and then passes through the focusing lens group, and the linear drive mechanism is used to adjust the distance between the diverging mirror and the focusing lens group, thereby adjusting the focal length of the laser beam. During the printing process, the distances from points on the printing plane to the reflector of the galvanometer unit are different, and the focal length of the laser beam can be adjusted in real time according to the requirements of the laser scanning path, so that the laser beam can be accurately focused on the printing plane for printing operations.

[0014] Preferably, the beam zoom unit further comprises a first housing, the focusing lens group, the diverging lens and the linear drive mechanism are all fixedly mounted in the first housing, and both ends of the first housing are provided with first light holes for the laser beam to pass through. The first housing can isolate external light interference and play a dustproof role, thereby ensuring the stability of the working environment during printing.

[0015] Preferably, a heat exchange plate is provided in the first shell, a second light hole for the laser beam to pass through is provided on the heat exchange plate, two first cooling medium channels are provided in the heat exchange plate, the first end of the first cooling medium channel is connected to a medium interface, the medium interface extends to the outside of the first shell, a second cooling medium channel is provided in the first shell, and the inlet and outlet of the second cooling medium channel are respectively connected to the second ends of the two first cooling medium channels. When in use, by introducing the cooling medium into the first medium interface, the cooling medium flows through the first first cooling medium channel, the second cooling medium channel and the second first cooling medium channel in sequence, and the cooling medium dissipates heat to the first shell and the heat sink, preventing the material from thermal expansion caused by the temperature increase, thereby improving stability.

[0016] Preferably, the apparatus further comprises a second shell, the second shell being fixedly connected to the front end of the first shell, the second shell having third light holes at both ends for the laser beam to pass through, and the detection end of the visual detection unit being arranged in the second shell. Since the detection end of the visual detection unit is arranged in the second shell, the interference of the image of the printing plane in the process of being reflected by the galvanometer unit and the dichroic mirror to the detection end in the visual detection unit can be reduced, thereby ensuring that the detection end can detect accurate data.

[0017] As a preference, it also includes a spot detection component arranged at one end of the galvanometer unit that emits light, the spot detection component including a mounting seat, a window sheet, a spot detection unit and a reflection unit, wherein the mounting seat is provided with a beam channel; the window sheet is used to divide the laser beam projected thereon into a reflected beam and a transmitted beam, the window sheet is arranged in the beam channel and is located at the exit end of the beam channel; the spot detection unit is used to detect the spot projected on its detection end; the reflection unit is used to reflect the reflected beam of the laser beam projected at a preset position on the window sheet to the detection end of the spot detection unit. When in use, the laser beam enters the beam channel, and when the laser beam is projected to the preset position on the window sheet, the laser beam is divided into a reflected beam and a transmitted beam by the window sheet. Among them, the transmitted beam is used to print in the printing area; the reflected beam is reflected to the detection end of the spot detection unit through the reflection unit, and the spot is identified by the detection end of the detection unit, thereby obtaining the morphological information of the spot. Since the transmitted beam can still perform printing when the spot of the reflected beam is detected, the spot detection work can be performed during the printing process, and the morphology of the spot can be corrected online. Furthermore, since the energy of the reflected laser beam is relatively low, there is no need to design an energy attenuation system to protect the detection end, making the overall structure compact and small, with better space advantages.

[0018] Preferably, the window sheet is configured to seal the exit end of the light beam channel. Since the window sheet seals the exit end of the light beam channel, the reflection unit is separated from the printing area to avoid mutual interference.

[0019] Preferably, a third cooling medium channel is provided inside the mounting seat, and the inlet and outlet of the third cooling medium channel are both opened outside the mounting seat. Since the laser beam generates heat when working, the temperature of the mounting seat and the inside of the mounting seat can be reduced by passing the cooling medium into the third cooling medium channel.

[0020] Preferably, a first mounting opening is provided on the side of the mounting seat, the reflecting unit is arranged in the first mounting opening, the reflecting unit comprises a third shell and a reflecting mirror group arranged inside the third shell, the third shell is fixedly connected in the first mounting opening, the light spot detection unit is fixedly connected in the third shell, the third shell is provided with a light inlet corresponding to the first mounting opening, and a light outlet corresponding to the detection end of the light spot detection unit, and the reflecting mirror group is configured to reflect the reflected light beam of the laser beam projected at the preset position to the detection end of the light spot detection unit. Since the reflecting mirror group is arranged inside the shell, the influence of the external environment on the reflecting mirror group is reduced.

[0021] Preferably, the reflector group includes a first reflector, a second reflector and a third reflector, wherein the first reflector and the second reflector are arranged in parallel, and the reflected light beam of the laser light beam projected on the preset position is reflected by the first reflector and the second reflector and then reflected onto the third reflector, and the third reflector is configured to reflect the reflected light beam projected thereon to the detection end of the light spot detection unit. The path length of the reflected light beam reaching the detection end of the light spot detection unit is equal to the path length of the transmitted light beam reaching the printing plane. Since the length of the reflected light beam needs to be the same as the length of the transmitted light beam, it can reflect the real information of the light spot transmitted by the transmitted light beam in the printing area. Since the first reflector and the second reflector are parallel to each other, the reflected light beam can be reflected multiple times between being reflected by the first reflector and the second reflector, thereby meeting the length requirement of the path of the reflected light beam and reducing the overall length of the reflection unit.

[0022] In summary, the high-speed dynamic focus tracking laser scanning system provided by the present invention has at least the following beneficial effects:

[0023] 1. It can monitor the splicing misalignment in real time during the laser scanning and printing process, and correct the splicing misalignment.

[0024] 2. It can dynamically track the spatial coordinate position of the focus of the laser beam in the three directions of X, Y, and Z axes, thereby ensuring the accuracy of the spatial position of the focus. In addition, the spatial coordinate position of the focus of the laser beam in the three directions of X, Y, and Z axes can be coordinated and adjusted through the beam zoom unit and the galvanometer unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 expending any novel work.

[0026] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0027] Figure 2 It is a schematic diagram of the three-dimensional structure of the light beam zoom unit in the present invention;

[0028] Figure 3 It is a front view of the beam zoom unit in the present invention;

[0029] Figure 4 yes Figure 3 Sectional view at AA in the middle;

[0030] Figure 5It is a schematic diagram of the assembly of the second housing, the dichroic mirror, the visual detection unit and the laser collimator in the present invention at a front side viewing angle;

[0031] Figure 6 It is a schematic diagram of the assembly of the second housing, the dichroic mirror, the visual detection unit and the laser collimator in the present invention at a rear side viewing angle;

[0032] Figure 7 is a schematic diagram of the three-dimensional structure of the light spot detection component in the present invention when viewed from a top perspective;

[0033] Figure 8 is a schematic diagram of the three-dimensional structure of the light spot detection component in the present invention when viewed from an upward angle;

[0034] Fig. 9 is a front view of the light spot detection assembly in the present invention;

[0035] Fig.10 yes Fig. 9 Sectional view at the middle BB;

[0036] Fig.11 yes Fig.10 The enlarged view at a in the middle;

[0037] Fig.12 It is a schematic diagram of the three-dimensional structure of the mounting seat in the present invention;

[0038] Fig.13 is a perspective view of the mounting seat of the present invention from a side perspective;

[0039] Fig.14 It is a perspective view of the heat exchange plate in the present invention from the front side.

[0040] The reference numerals include: dichroic mirror 1, beam zoom unit 2, focusing lens group 201, first lens 2011, second lens 2012, divergent mirror 202, linear drive mechanism 203, voice coil motor 2031, second fixing seat 2032, second through hole 2033, first shell 204, bottom shell 2041, cover plate 2042, first light hole 205, heat exchange plate 206, second light hole 207, first cooling medium channel 208, medium interface 209, first fixing seat 210, first through hole 211, first lens barrel 212, second lens barrel 213, galvanometer unit 3, visual detection unit 4, The second shell 5, the third light hole 6, the mounting seat 7, the window piece 8, the reflecting unit 9, the third shell 901, the reflecting mirror group 902, the first reflecting mirror 9021, the second reflecting mirror 9022, the third reflecting mirror 9023, the light outlet 903, the second mirror seat 904, the light spot detection unit 10, the light beam channel 11, the laser beam 12, the reflected light beam 13, the transmitted light beam 14, the third cooling medium channel 15, the first mounting port 16, the first mirror seat 17, the avoidance hole 18, the second mounting port 19, the end cover 20, the third through hole 21, the laser collimator 22, the attenuation filter 23, the vent 24, and the flange 25. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solution of the present invention, Figure 1-14 The present invention is further described in detail with specific implementation modes.

[0042] See also Figure 1-14 , a high-speed dynamic tracking focus laser scanning system provided in this embodiment includes: a laser collimator 22, a dichroic mirror 1, a beam zoom unit 2 and a galvanometer unit 3 arranged in sequence on the path of the laser beam 12 from front to back, and a visual detection unit 4 located outside the path. Among them, the beam zoom unit 2 is configured to be able to focus the laser beam 12 and adjust the focal length of the laser beam 12; the galvanometer unit 3 is configured to be able to reflect the laser beam 12 to the printing plane and adjust the plane position of the laser beam 12 reflected to the printing plane; the dichroic mirror 1 is configured to allow the laser beam 12 to pass through; the detection end of the visual detection unit 4 is configured to be able to obtain an image of the printed part formed on the printing plane through the dichroic mirror 1 and the galvanometer unit 3. The dichroic mirror 1 is a prior art, and specifically, a dichroic mirror in the prior art that can allow the laser beam with a wavelength of 1064nm to pass through and can reflect visible light with a wavelength of 340nm to 780nm can be used.

[0043] See also Figure 4The beam zoom unit 2 includes a focusing lens group 201, a diverging mirror 202 and a linear drive mechanism 203 which are arranged in sequence from left to right. The diverging mirror 202 is fixed at the working end of the linear drive mechanism 203. The laser beam 12 enters from the front side of the beam zoom unit 2 and is emitted from the rear side. The laser beam 12 first passes through the diverging mirror 202 and then passes through the focusing lens group 201. The linear drive mechanism 203 is used to adjust the distance between the diverging mirror 202 and the focusing lens group 201, thereby adjusting the focal length of the laser beam 12 passing through the focusing lens group 201. The focusing lens group 201 includes a first lens 2011 and a second lens 2012. The first lens 2011 is located on the right side of the second lens 2012. The laser beam 12 passes through the first lens 2011 and then passes through the second lens 2012. The left side of the first lens 2011 is a convex surface and the right side is a plane; the left and right sides of the second lens 2012 are both convex surfaces; the diverging mirror 202 is a lens with concave surfaces on both sides.

[0044] See also Figure 2 The beam zoom unit 2 also includes a first housing 204, in which the focusing lens group 201, the diverging lens 202 and the linear drive mechanism 203 are all fixedly installed. Both ends of the first housing 204 are provided with a first light hole 205 for the laser beam 12 to pass through. Figure 4 Specifically, the first housing 204 includes a bottom housing 2041 and a cover plate 2042. The top of the bottom housing 2041 is open. The cover plate 2042 is bolted to the top of the bottom housing 2041. The cover plate 2042 closes the top opening of the bottom housing 2041. The first light hole 205 is specifically provided at the left and right ends of the bottom housing 2041. A first fixing seat 210 is fixedly installed in the first housing 204. The first fixing seat 210 is bolted to the bottom housing 2041. A first through hole 211 is provided in the middle of the first fixing seat 210 for the laser beam 12 to pass through. A first lens barrel 212 is bolted to the left side of the first fixing seat 210. A second lens barrel 213 is sleeved on the outer side of the first lens barrel 212. The focusing lens group 201 is fixed to the inner side of the left section of the second lens barrel 213.

[0045] Please continue reading Figure 4, a heat exchange plate 206 is provided in the first shell 204, and a second light hole 207 is provided in the middle of the heat exchange plate 206 for the laser beam 12 to pass through. Two first cooling medium channels 208 are provided in the heat exchange plate 206, and the first end of the first cooling medium channel 208 is connected to a medium interface 209, and the medium interface 209 extends to the outside of the first shell 204. A second cooling medium channel is provided in the first shell 204, and the inlet and outlet of the second cooling medium channel are respectively connected to the second ends of the two first cooling medium channels 208. The second cooling medium channel is specifically arranged inside the bottom plate on the lower side of the bottom shell 2041, and the outlet and inlet of the second cooling medium channel are both opened on the upper surface of the bottom plate on the lower side of the bottom shell 2041. The outlet and inlet of the second cooling medium channel are respectively connected to the second ends of the two first cooling medium channels 208, that is, the outlet and inlet of the second cooling medium channel are respectively connected to the lower ends of the two first cooling medium channels 208. The distribution of the first cooling medium channel 208 on the heat exchange plate 206 is detailed. Fig.14 .

[0046] Please continue reading Figure 4 The linear drive mechanism 203 includes a second fixed seat 2032 and a voice coil motor 2031. The second fixed seat 2032 is fixedly connected to the first housing 204. A second through hole 2033 is provided in the middle of the second fixed seat 2032 for the laser beam 12 to pass through. The second fixed seat 2032 is close to the right end of the first housing 204. The stator of the voice coil motor 2031 is fixedly mounted on the second fixed seat 2032, and the mover of the voice coil motor 2031 is fixedly connected to the divergent mirror 202. The mover of the voice coil motor 2031 can drive the divergent mirror 202 to approach and move away from the divergent mirror 202 group.

[0047] See also Figure 1 , Figure 5 and Figure 6 , further comprising a second shell 5, the second shell 5 being fixedly connected to the front end of the first shell 204, the front and rear ends of the second shell 5 being provided with a third light hole 6 for the laser beam 12 to pass through, and the detection end of the visual detection unit 4 being arranged in the second shell 5. A first mirror seat 17 is fixedly installed in the second shell 5, the first mirror seat 17 being provided with an avoidance hole 18 for the laser beam 12 to pass through, and the dichroic mirror 1 being fixedly installed on the first mirror seat 17. Among them, the visual detection unit 4 is a prior art, and specifically an industrial camera in the prior art can be adopted. In order to facilitate the installation of the first mirror seat 17 and the dichroic mirror 1, a second mounting port 19 is provided on the right side of the second shell 5, and an end cap 20 is detachably connected to the second mounting port 19, and a third through hole 21 is provided on the end cap 20 for the detection end of the visual detection unit 4 to pass through, and the visual detection unit 4 is detachably connected to the right side of the end cap 20.

[0048] The galvanometer unit 3 is a prior art, and the galvanometer unit 3 is a 2D galvanometer unit. The galvanometer unit 3 specifically includes an X-axis galvanometer, a Y-axis galvanometer, a first motor, and a second motor. The first motor is used to drive the X-axis galvanometer to deflect, and the second motor is used to drive the Y-axis galvanometer to deflect. The X-axis galvanometer is driven to deflect by the first motor, and the reflection angle of the X-axis galvanometer is adjusted, thereby adjusting the position of the laser beam 12 projected on the printing plane in the X-axis direction; the Y-axis galvanometer is driven to deflect by the second motor, and the reflection angle of the Y-axis galvanometer is adjusted, thereby adjusting the position of the laser beam 12 projected on the printing plane in the Y-axis direction; through the cooperation of the X-axis galvanometer and the Y-axis galvanometer, the laser beam 12 can be adjusted to be projected to any position on the printing plane. When in use, the laser beam 12 enters from the entrance end of the front side of the galvanometer, and reaches the printing plane after passing through the exit on the lower side of the galvanometer unit 3.

[0049] See also Figure 1 and Figure 7-13 , and also includes a spot detection component arranged at one end of the galvanometer unit 3 where light is emitted, and the spot detection component is arranged at the lower side of the galvanometer unit 3. Specifically, the spot detection component includes a mounting seat 7, a window piece 8, a spot detection unit 10 and a reflection unit 9, wherein a beam channel 11 is provided on the mounting seat 7, the upper end of the beam channel 11 is an entrance end, and the lower end is an exit end; the window piece 8 is used to divide the laser beam 12 projected thereon into a reflected beam 13 and a transmitted beam 14. Specifically, the window piece 8 is used to divide the laser beam 12 passing therethrough into a reflected beam 13 with a percentage of less than 1% and a transmitted beam 14 with a percentage of more than 99%. The window piece 8 is arranged in the beam channel 11 and is located at the exit end of the beam channel 11. The spot detection unit 10 is used to detect the light spot projected on its detection end, specifically to detect the morphological information of the light spot projected on its detection end. The spot detection unit 10 is a prior art, and specifically can be a planar array camera in the prior art. The reflection unit 9 is used to reflect the reflected light beam 13 of the laser light beam 12 projected on the preset position on the window plate 8 to the detection end of the light spot detection unit 10. The window plate 8 is configured to close the exit end of the light beam channel 11.

[0050] See also Fig.12 A first mounting opening 16 is provided on the side of the mounting seat 7, and the reflection unit 9 is arranged in the first mounting opening 16. Please continue to refer to Figure 10-12 The reflection unit 9 includes a third housing 901 and a reflector group 902 disposed inside the third housing 901. The third housing 901 is fixedly connected to the first mounting opening 16. The light spot detection unit 10 is fixedly connected to the third housing 901. The third housing 901 is provided with a light inlet corresponding to the first mounting opening 16 and a light outlet 903 corresponding to the detection end of the light spot detection unit 10. The reflector group 902 is configured to reflect the reflected light beam 13 of the laser light beam 12 projected at a preset position to the detection end of the light spot detection unit 10. Please refer to Fig.10In addition, the mounting seat 7 is provided with a vent hole 24, through which inert gas can be easily introduced into the mounting seat 7 after assembly to maintain the stability of the laser beam propagation medium. Specifically, the vent hole 24 is provided at the annular flange 25 at the lower part of the mounting seat 7, the inlet of the vent hole 24 is located on the upper surface of the flange 25, and the outlet of the vent hole 24 is located inside the mounting seat 7.

[0051] Please continue reading Fig.10 and Fig.11 Specifically, the reflector group 902 includes a first reflector 9021, a second reflector 9022 and a third reflector 9023. The first reflector 9021 and the second reflector 9022 are arranged in parallel. The reflected light beam 13 of the laser light beam 12 projected at the preset position is reflected by the first reflector 9021 and the second reflector 9022 and then reflected to the third reflector 9023. The third reflector 9023 is configured to reflect the reflected light beam 13 projected thereon to the detection end. The path length of the reflected light beam 13 reaching the detection end of the light spot detection unit 10 is equal to the path length of the transmitted light beam 14 reaching the printing plane. More specifically, a second mirror seat 904 is fixedly connected inside the third shell 901, and the third reflector 9023 is fixedly connected to the second mirror seat 904. The third reflector 9023 is inclined at 40° toward the lower right. For details, please refer to Fig.11 , the angle between the mirror surface of the third reflector 9023 and the horizontal plane is 40°. In the specific use process, the distance from the reflected light beam 13 of the laser light beam 12 projected on the preset position on the window sheet 8 to the detection end of the light spot detection unit 10 through the reflector group 902 is equal to the distance from the transmitted light beam 14 to the printing plane. Since the length of the reflected light beam 13 is the same as the length of the transmitted light beam 14, the morphological information of the light spot transmitted by the transmitted light beam 14 in the printing area can be reflected. The path of the reflected light beam 13 is longer, resulting in a longer length of the reflection unit 9. Since the first reflector 9021 and the second reflector 9022 are parallel to each other, the reflected light beam 13 can be reflected multiple times between the reflections through the first reflector 9021 and the second reflector 9022, thereby meeting the length requirement of the path of the reflected light beam 13 and reducing the overall length of the reflection unit 9. In order to further prevent the high-energy reflected light beam 13 from bringing heat to the light spot detection unit 10, as a preference, an attenuation filter 23 is provided between the third reflector 9023 and the detection end of the light spot detection unit 10.

[0052] Please continue reading Fig.10Since the laser beam 12 is projected onto the window 8 from above, in order to make the reflected beam 13 reflect onto the first reflector 9021 when the angle with the vertical direction is small. Preferably, the first reflector 9021 is arranged above the second reflector 9022, the first reflector 9021 is close to the entrance end of the beam channel 11, the second reflector 9022 is close to the exit end of the beam channel 11, and the length of the first reflector 9021 extending into the beam channel 11 is greater than the length of the second reflector 9022 extending into the beam channel 11. Since the length of the first reflector 9021 extending into the beam channel 11 is longer, the first reflector 9021 can receive the reflected beam 13 closer to the direction perpendicular to the window 8, and the occupation range of the internal space of the beam channel 11 by the reflector group 902 can be reduced.

[0053] See also Fig.13 A third cooling medium channel 15 is provided inside the mounting seat 7, and the inlet and outlet of the third cooling medium channel 15 are both opened on the outside of the mounting seat 7. In order to improve the overall heat dissipation efficiency of the mounting seat 7, the third cooling medium channel 15 is arranged in a zigzag shape along the circumferential direction of the mounting seat 7 to increase the heat exchange area of ​​the cooling medium.

[0054] During the working process, when in use, several dynamic focus scanning systems are used to perform scanning and printing work at the same time. Each dynamic focus scanning system is responsible for scanning and printing the corresponding area, and each dynamic focus scanning system is configured with a corresponding laser. A laser beam 12 is emitted by a laser, and the laser beam 12 passes through the laser collimator 22, the dichroic mirror 1, and the beam zoom unit 2 in sequence along the path to reach the galvanometer unit 3. The laser beam 12 is focused by the beam zoom unit 2, and the position of the laser beam 12 reflected on the printing plane is adjusted by the galvanometer unit 3. The printing plane is located in the molding chamber. The image of the printed part formed on the printing plane is reflected to the detection end of the visual detection unit 4 by the galvanometer unit 3 and the dichroic mirror 1. In order to enable the visual detection unit 4 to recognize a clear image, a light source for illumination is set in the molding chamber. The image obtained by the visual detection unit 4 can identify whether the molded print deviates from the preset printing position, and the splicing misalignment can be reflected, so that the splicing misalignment can be monitored in real time during the printing process. According to the information of the splicing misalignment, before scanning and printing the next layer, the scanning path of the laser beam 12 on the printing plane is adjusted by the galvanometer unit 3 to correct the splicing misalignment. Among them, since the galvanometer unit 3 adjusts the position of the laser beam 12 reflected on the printing plane during the printing process, the printing plane is scanned according to the preset path. During the scanning process, the galvanometer unit 3 can reflect the image of the part being scanned and the adjacent part that has been scanned to the dichroic mirror 1, and the dichroic mirror 1 is reflected to the detection end of the visual detection unit 4, so that the molding condition of the printed part formed on the scanning path can be obtained in real time. In the process of scanning and printing, the laser beam 12 is reflected to the printing plane by the galvanometer unit 3, and the laser beam 12 first enters the beam channel 11, and then the laser beam 12 is divided into a reflected beam 13 and a transmitted beam 14 by the window piece 8. Among them, the transmitted beam 14 reaches the printing area for scanning and printing. When the laser beam 12 is projected onto the preset position on the window sheet 8, the reflected beam 13 is reflected by the reflection unit 9 to the detection end of the light spot detection unit 10, and the light spot is identified by the detection end of the detection unit, thereby obtaining the morphological information of the light spot. Since the transmitted beam 14 can still perform printing when the light spot of the reflected beam 13 is detected, the light spot detection work can be performed during the printing process, so that the light spot detection work can be performed online. In addition, since the energy of the reflected beam 13 of the laser beam 12 is relatively low, it is not easy to cause damage to the light spot detection unit 10 when it is detected by the light spot detection unit 10, and the safety risk is low. The heat generated by the reflected beam 13 is also relatively low, so that the operating temperature of the light spot detection unit 10 is relatively low, which is conducive to ensuring the working stability and service life of the light spot detection unit 10.In addition, by using information such as the size and shape of the light spot detected by the light spot detection unit 10, it can be determined whether the focal length of the laser beam 12 deviates from the printing plane. If it deviates from the printing plane, the linear drive mechanism 203 can be adjusted to adjust the distance between the divergent mirror 202 and the focusing lens group 201, thereby adjusting the focal length of the laser beam 12 so that the light spot working on the printing plane can be adjusted to the required size.

[0055] It should be noted that the words indicating direction in this article, such as up and down, are all based on Figure 1 The setting of the direction is only for the convenience of description and has no other specific meaning.

[0056] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the article or device including the above elements.

[0057] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A high-speed dynamic focus tracking laser scanning system, characterized in that: It comprises a dichroic mirror (1), a beam zoom unit (2) and a galvanometer unit (3) which are sequentially arranged on the path of a laser beam (12), and a visual detection unit (4) which is located outside the path; The beam zoom unit (2) is configured to be able to focus the laser beam (12) and to be able to adjust the focal length of the laser beam (12); The galvanometer unit (3) is configured to be capable of reflecting the laser beam (12) onto a printing plane, and capable of adjusting a plane position of the laser beam (12) reflected onto the printing plane; The dichroic mirror (1) is configured to allow the laser beam (12) to pass through; The detection end of the visual detection unit (4) is configured to be able to acquire an image of a printed part formed on the printing plane through a dichroic mirror (1) and a galvanometer unit (3).

2. The high-speed dynamic focus tracking laser scanning system according to claim 1, characterized in that: The beam zoom unit (2) comprises a focusing lens group (201), a diverging mirror (202) and a linear drive mechanism (203); the diverging mirror (202) is fixed to a working end of the linear drive mechanism (203); the linear drive mechanism (203) is used to adjust the distance between the diverging mirror (202) and the focusing lens group (201), thereby adjusting the focal length of the laser beam (12).

3. The high-speed dynamic focus tracking laser scanning system according to claim 2, characterized in that: The beam zoom unit (2) further comprises a first shell (204), wherein the focusing lens group (201), the diverging lens (202) and the linear drive mechanism (203) are all fixedly mounted in the first shell (204), and both ends of the first shell (204) are provided with first light holes (205) for the laser beam (12) to pass through.

4. The high-speed dynamic focus tracking laser scanning system according to claim 3, characterized in that: A heat exchange plate (206) is provided in the first shell (204), and a second light hole (207) is provided on the heat exchange plate (206) for the laser beam (12) to pass through. Two first cooling medium channels (208) are provided in the heat exchange plate (206), and the first end of the first cooling medium channel (208) is connected to a medium interface (209), and the medium interface (209) extends to the outside of the first shell (204). A second cooling medium channel is provided in the first shell (204), and the inlet and outlet of the second cooling medium channel are respectively connected to the second ends of the two first cooling medium channels (208).

5. The high-speed dynamic focus tracking laser scanning system according to claim 3, characterized in that: It also includes a second shell (5), the second shell (5) is fixedly connected to the front end of the first shell (204), both ends of the second shell (5) are provided with third light holes (6) for the laser light beam (12) to pass through, and the detection end of the visual detection unit (4) is arranged in the second shell (5).

6. A high-speed dynamic focus tracking laser scanning system according to any one of claims 2-5, characterized in that: The invention also comprises a light spot detection component arranged at the light output end of the galvanometer unit (3), the light spot detection component comprising a mounting seat (7), a window plate (8), a light spot detection unit (10) and a reflection unit (9), wherein the mounting seat (7) is provided with a light beam channel (11); the window plate (8) is used to divide the laser light beam (12) projected thereon into a reflected light beam (13) and a transmitted light beam (14); the window plate (8) is arranged in the light beam channel (11) and is located at the exit end of the light beam channel (11); the light spot detection unit (10) is used to detect the light spot projected on the detection end thereof; and the reflection unit (9) is used to reflect the reflected light beam (13) of the laser light beam (12) projected at a preset position on the window plate (8) to the detection end of the light spot detection unit (10).

7. The high-speed dynamic focus tracking laser scanning system according to claim 6, characterized in that: The window plate (8) is configured to close the exit end of the light beam channel (11).

8. The high-speed dynamic focus tracking laser scanning system according to claim 6, characterized in that: A third cooling medium channel (15) is provided inside the mounting seat (7), and an inlet and an outlet of the third cooling medium channel (15) are both opened on the outside of the mounting seat (7).

9. The high-speed dynamic focus tracking laser scanning system according to claim 6, characterized in that: A first mounting opening (16) is provided on the side of the mounting seat (7); the reflection unit (9) is arranged in the first mounting opening (16); the reflection unit (9) comprises a third shell (901) and a reflection mirror group (902) arranged inside the third shell (901); the third shell (901) is fixedly connected in the first mounting opening (16); the light spot detection unit (10) is fixedly connected in the third shell (901); a light inlet corresponding to the first mounting opening (16) and a light outlet (903) corresponding to a detection end of the light spot detection unit (10) are provided on the third shell (901); the reflection mirror group (902) is configured to be able to reflect a reflected light beam (13) of the laser light beam (12) projected at the preset position to the detection end of the light spot detection unit (10).

10. The high-speed dynamic focus tracking laser scanning system according to claim 9, characterized in that: The reflector group (902) comprises a first reflector (9021), a second reflector (9022) and a third reflector (9023); the first reflector (9021) and the second reflector (9022) are arranged in parallel; a reflected light beam (13) of the laser light beam (12) projected on the preset position is reflected by the first reflector (9021) and the second reflector (9022) and then reflected onto the third reflector (9023); the third reflector (9023) is configured to reflect the reflected light beam (13) projected thereon to a detection end of the light spot detection unit (10).

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