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CN-122007448-A - Automatic calibration and printing monitoring device and method for laser selective melting forming equipment

CN122007448ACN 122007448 ACN122007448 ACN 122007448ACN-122007448-A

Abstract

The application relates to the technical field of selective laser melting, in particular to an automatic calibration and printing monitoring device and method of selective laser melting forming equipment, comprising a forming cavity; the forming device comprises a forming cavity, a forming cylinder, a base plate and a base plate, wherein the forming cavity is arranged in the base plate, the forming cylinder is arranged in the forming cavity, a scraper frame is arranged above the forming cylinder and used for installing a powder spreading scraper, and the base plate is connected to the forming cylinder and can be driven by the forming cylinder to enable the scraper to spread powder layer by layer to the surface of the base plate by descending layer by layer. According to the application, through the integrated substrate automatic leveling, the in-situ light path calibration based on the production substrate and the single-camera double-light path automatic switching monitoring system, the traditional low-efficiency mode relying on manual and external instruments and off-line operation is improved, the equipment preparation time is shortened to ten minutes from several hours, the vibration mirror and splicing calibration precision is stably improved to the micron level, and the consistency and traceability of the technological process are ensured through integrated continuous monitoring.

Inventors

  • CHANG LILI
  • SHEN SAIGANG
  • XING FEI
  • HU JIARUI

Assignees

  • 南京中科煜宸激光技术有限公司

Dates

Publication Date
20260512
Application Date
20260121

Claims (10)

  1. 1. An automatic calibration and print monitoring device for a laser selective melting forming device, comprising: a forming chamber (100); The forming cylinder (10) is arranged in the forming cavity (100), a scraper rest (11) is arranged above the forming cylinder (10), and the scraper rest (11) is used for installing a powder spreading scraper; a base plate (20) connected to the molding cylinder (10) and drivable by the molding cylinder (10) to laminate the doctor blade layer by layer against the surface of the base plate (20) by lowering layer by layer; A substrate leveling member (30) including a substrate monitoring unit including a first laser displacement sensor (31) and a second laser displacement sensor (32) mounted to a doctor blade holder (11), and a substrate posture adjustment unit (34) connected below a substrate (20) for adjusting a posture of the substrate (20); A dual laser galvanometer system (40) comprising a first laser galvanometer unit (41) acting on a first area of the surface of the substrate (20) and a second laser galvanometer unit (42) acting on a second area of the surface of the substrate (20), wherein the first laser galvanometer unit (41) and the second laser galvanometer unit (42) are used for sintering metal powder of a target powder layer above the substrate (20); A monitoring component (50) comprising a CCD camera (51) and a lens switching mechanism (52), wherein the field of view of the CCD camera (51) comprises the whole area of the substrate (20), and the lens switching mechanism (52) is used for switching a high-light-transmission lens (521) or a laser protection lens (522) on the optical path of the field of view of the CCD camera (51); The controller is electrically connected with the substrate leveling component (30), the double-laser galvanometer system (40) and the monitoring component (50); wherein the controller is configured to perform an in-situ auto-calibration procedure comprising: A substrate leveling step of driving the scraper frame (11) to move, enabling the first laser displacement sensor (31) and the second laser displacement sensor (32) to measure the distance on the surface of the substrate (20), and controlling the substrate posture adjusting unit (34) to adjust the substrate (20) to be horizontal; After the substrate leveling step, controlling the dual laser galvanometer system (40) to directly print a calibration pattern on the surface of the leveled substrate (20), controlling the lens switching mechanism (52) to enable the high-transmittance lens (521) to cut into a light path, and shooting the calibration pattern by the CCD camera (51); the galvanometer calibration step comprises the following steps: Shan Zhenjing precision calibration, namely controlling the first laser galvanometer unit (41) to print a first mark pattern at a plurality of first preset positions (21) in the first area, and controlling the second laser galvanometer unit (42) to print a second mark pattern at a plurality of first preset positions (21) in the second area; Controlling the first laser galvanometer unit (41) and the second laser galvanometer unit (42) to print splicing calibration patterns at a plurality of second preset positions (22) in a superposition intersection area (202) of the first area and the second area; the controller is further configured to analyze images of the first mark pattern, the second mark pattern and the spliced calibration pattern photographed by the CCD camera (51), calculate scanning position errors of the first laser galvanometer unit (41) and the second laser galvanometer unit (42) and splicing errors of the first laser galvanometer unit and the second laser galvanometer unit in the crossing area (202), and generate corresponding calibration parameters to update a galvanometer control system; The controller is further configured to execute a printing monitoring flow, wherein during the printing process of the laser emitted by the dual laser galvanometer system (40), the lens switching mechanism (52) is controlled to cut the laser protection lens (522) into a view field optical path of the CCD camera (51) for process monitoring, and during a non-laser emitting stage, the lens switching mechanism (52) is controlled to cut the high-transmittance lens (521) into the optical path for image acquisition.
  2. 2. The apparatus for automatic calibration and print monitoring of a laser selective melt forming device according to claim 1, wherein the controller, in the galvanometer calibration step, is configured to: After Shan Zhenjing precision calibration is completed, judging whether the scanning position error is smaller than a first preset threshold value or not; If so, the calibration parameters are generated based on the calculated error model and graphic printing of a part of the unprinted first predetermined locations (21) is skipped.
  3. 3. The automatic calibration and print monitoring device of a laser selective melt forming apparatus according to claim 1 or 2, characterized in that a plurality of the first predetermined positions (21) are distributed in a rectangular array in the first and second areas, and a plurality of the second predetermined positions (22) are distributed in a rectangular array in the intersection area (202).
  4. 4. The automatic calibration and printing monitoring device of the laser selective melt forming equipment according to claim 1, wherein in the substrate leveling step, the doctor blade holder (11) is driven to move above the substrate (20) so that the first laser displacement sensor (31) and the second laser displacement sensor (32) form three ranging points on the surface of the substrate (20), the substrate posture adjustment unit (34) comprises a first electric lifting column (341), a second electric lifting column (342) and a third electric lifting column (343), the first electric lifting column (341), the second electric lifting column (342) and the third electric lifting column (343) are arranged in an isosceles right triangle, and are respectively connected to three corners of the bottom surface of the substrate (20), the three ranging points respectively correspond to the positions of the first electric lifting column (341), the second electric lifting column (342) and the third electric lifting column (343), and the three ranging points of the substrate (20) are adjusted by the first electric lifting column (341), the second electric lifting column (342) and the third electric lifting column (343), so that the three ranging points are at preset data.
  5. 5. The automatic calibration and print monitoring device of a laser selective melt forming apparatus according to claim 1, wherein the substrate leveling component (30) further comprises sensor calibration plates (33) arranged on both sides of the substrate (20), the controller further configured to: Before the galvanometer calibration step starts, the first laser displacement sensor (31) and the second laser displacement sensor (32) are controlled to move to the position above the sensor calibration plate (33) to perform reference calibration of the height of the sensor.
  6. 6. The automatic calibration and print monitoring device of a laser selective melt forming apparatus according to claim 1, characterized in that the lens switching mechanism (52) comprises a linear driving structure (523), the laser protection lens (522) is connected to the linear driving structure (23), the linear driving structure (523) is used for driving the laser protection lens (522) to cut in or cut out a view field optical path of the CCD camera (51), and the high light transmission lens (521) is connected to a mounting seat of the CCD camera (51) and is kept in the view field optical path of the CCD camera (51).
  7. 7. The automatic calibration and print monitoring device of the laser selective melt forming equipment according to claim 1, wherein the high light transmittance lens (521) is quartz glass with a light transmittance of not less than 95%, and the laser protection lens (522) is OD 6-grade laser protection glass for a wavelength of 1064 nm.
  8. 8. A method for automatically calibrating and printing a selective laser melting forming device, characterized in that the device for automatically calibrating and printing a selective laser melting forming device according to any one of claims 1-7 comprises the following steps: A step of automatically leveling the substrate, in which the surface of the substrate (20) is scanned by a laser displacement sensor arranged on a scraper frame (11) in a forming chamber (100), and the substrate (20) is adjusted to be horizontal by a substrate posture adjusting unit (34); An in-situ optical path calibration step, after the substrate auto-leveling step, of performing the following operations within the forming chamber (100) without dismantling the substrate (20): Controlling the dual laser galvanometer system (40) to print a calibration pattern distributed in an array on the surface of the substrate (20); controlling the monitoring component (50) to cut the high-light-transmission lens (521) into the light path of the CCD camera (51) and shooting the calibration graph; analyzing the image, calculating a galvanometer scanning error and a laser splicing error, and automatically updating calibration parameters; the printing flow monitoring step comprises the steps of controlling a high-transmittance lens (521) to cut into a light path to detect powder paving quality after powder paving, controlling a laser protection lens (522) to cut into the light path to monitor in real time in the laser melting process, and controlling the high-transmittance lens (521) to cut into the light path to detect the surface of a finished product after printing is finished.
  9. 9. The method for automatic calibration and print monitoring of a laser selective melt forming apparatus according to claim 8, wherein the in-situ optical path calibration step comprises an adaptive calibration sub-step of: controlling the dual laser galvanometer system (40) to print calibration patterns for the first time at all first preset positions (21) and analyzing the calibration patterns; If the analysis result shows that the error is lower than the preset tolerance, the subsequent pattern printing at the first preset position (21) is terminated, and the calibration parameters are directly generated based on the existing data.
  10. 10. The automatic calibration and print monitoring method of a laser selective melt forming apparatus according to claim 9, wherein the calibration pattern printing at the first predetermined location (21) comprises a plurality of batches, each batch having a first marking pattern printed by a first laser galvanometer unit (41) and a second marking pattern printed by a second laser galvanometer unit (42), wherein the first marking pattern and the second marking pattern are concentric circles of unequal diameters.

Description

Automatic calibration and printing monitoring device and method for laser selective melting forming equipment Technical Field The invention relates to the technical field of selective laser melting, in particular to an automatic calibration and printing monitoring device and method for selective laser melting forming equipment. Background The laser selective melting technology is used as a core means for high-end metal additive manufacturing and is widely applied to the fields of aerospace, medical appliances and the like. With the increase in size and complexity of the parts, multi-laser cooperative forming equipment has become mainstream, but higher requirements are put on the precision, efficiency and automation level of the equipment. Currently, the operation of the equipment still depends on the experience and manual intervention of operators, such as a vibrating mirror size precision calibration method disclosed in publication No. CN119714063A and a multi-laser quick lap joint method for additive manufacturing equipment disclosed in publication No. CN 119426617A. Before printing, the substrate leveling and the light path calibration are required to be completed manually, the process is tedious and time-consuming, the precision is obviously affected by human factors, and in printing, the monitoring means for powder spreading quality, molten pool state and forming defects are limited, or a plurality of independent systems are relied on, so that the equipment structure is complex, the cost is high, and a data chain is broken. In the process, since the monitoring camera and the optical path of the existing equipment are not designed for high-precision metering, the imaging of the existing equipment has non-negligible and unstable distortion, and the existing equipment lacks a high-precision calibration target which is unified with a printing reference and can be measured in situ, so that a reliable closed loop calibration cannot be formed inside the equipment. The off-line calibration mode of moving the special calibration plate out of the equipment and measuring by means of an external high-precision imager is forced to be generally adopted in the industry, so that the efficiency is low, secondary errors are introduced in disassembly and transportation, and the precision consistency of long-term stable work is difficult to ensure. Disclosure of Invention The invention aims at overcoming the defects of the prior art, and provides an automatic calibration and printing monitoring device of laser selective melting forming equipment, which comprises the following components: A forming chamber; the forming cylinder is arranged in the forming cavity, a scraper rest is arranged above the forming cylinder, and the scraper rest is used for installing a powder spreading scraper; The base plate is connected to the forming cylinder and can be driven by the forming cylinder, and the scraper can be enabled to lay powder layer by layer on the surface of the base plate by descending layer by layer; A substrate leveling member including a substrate monitoring unit including a first laser displacement sensor and a second laser displacement sensor mounted to a doctor frame, and a substrate posture adjustment unit connected to a lower side of a substrate for adjusting a posture of the substrate; The double-laser galvanometer system comprises a first laser galvanometer unit acting on a first area of the surface of the substrate and a second laser galvanometer unit acting on a second area of the surface of the substrate, wherein the first laser galvanometer unit and the second laser galvanometer unit are used for sintering metal powder of a target powder layer above the substrate; The monitoring component comprises a CCD camera and a lens switching mechanism, wherein the field of view of the CCD camera comprises the whole substrate area, and the lens switching mechanism is used for switching a high-light-transmission lens or a laser protection lens on a field of view light path of the CCD camera; the controller is electrically connected with the substrate leveling component, the double-laser vibrating mirror system and the monitoring component; wherein the controller is configured to perform an in-situ auto-calibration procedure comprising: a substrate leveling step, namely driving the scraper rest to move, enabling the first laser displacement sensor and the second laser displacement sensor to range the surface of the substrate, and controlling the substrate posture adjusting unit to adjust the substrate to be horizontal; After the substrate leveling step, controlling the dual-laser galvanometer system to directly print a calibration pattern on the leveled substrate surface, controlling the lens switching mechanism to enable a high-light-transmission lens to cut into a light path, and shooting the calibration pattern by the CCD camera; the galvanometer calibration step comprises the following steps: shan Zhenjing performing p