Selective laser sintering melting channel defect monitoring and compensating equipment and method based on machine vision

Abstract

The invention provides a selective laser sintering melting channel defect monitoring and compensating device and method based on machine vision. The device comprises an upper computer, a powder laying module, a vision monitoring module, a laser scanning module and a compensating module. The powder spreading module comprises a powder spreading device and a powder spreading platform, and the powder spreading device is used for spreading powder on the powder spreading platform; the laser scanning module is used for conducting laser scanning on the powder on the powder laying platform, and finally a workpiece is formed. A melting channel is formed when powder is scanned by laser; the visual monitoring module is arranged at the position close to the powder laying platform and used for monitoring the melting channel defect, the powder laying state and the melting channel compensation result and transmitting monitoring data to the upper computer. And the compensation module is used for carrying out material supplementing and laser scanning repair treatment on the to-be-compensated area according to the melt channel defect data fed back by the upper computer. The selective laser sintering technology and the machine vision technology are adopted, melt channel defect monitoring and compensation in the metal printing process are achieved, precision is high, and the forming structure performance is good.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular, to an apparatus and method for monitoring and compensating for defects in a selective laser sintering melt track based on machine vision. Background Art

[0002] After nearly 40 years of development, additive manufacturing technology has shifted from initial prototype manufacturing to direct manufacturing and batch manufacturing. However, additive manufacturing technologies based on powder beds, represented by SLS, may have defects during the forming process, resulting in forming failures. Current research is difficult to cover all factors in complex production environments, and there are no relatively accurate research results on the defects generated layer by layer in workpieces, making it difficult to be applied in actual production processes. Therefore, establishing an online monitoring and compensation system for additive manufacturing defects to monitor and compensate for workpiece defects in real time during the manufacturing process is an inevitable requirement for promoting the further development and application of additive manufacturing technology. Selective laser sintering (SLS) is an additive manufacturing technology widely used in fields such as aerospace, medical devices, and automotive manufacturing. However, it is prone to defects such as incomplete sintering, pores, and deformation during the production process, seriously affecting the quality and performance of products. Traditional defect detection methods rely on post-processing detection, which is not only time-consuming and laborious but also unable to correct problems in production in a timely manner. The method for monitoring and compensating melt track defects based on machine vision can achieve real-time, efficient, and accurate defect monitoring and compensation, significantly improving production efficiency and product quality. Summary of the Invention

[0003] In view of the above-mentioned technical problems, an apparatus and method for monitoring and compensating for defects in a selective laser sintering melt track based on machine vision are provided. The present invention mainly uses selective laser sintering technology and machine vision technology to achieve melt track monitoring and compensation, with higher precision in additive manufacturing, better forming structure performance, and the ability to meet the manufacturing of more complex structures.

[0004] The technical means adopted by the present invention are as follows:

[0005] An apparatus for monitoring and compensating for defects in a selective laser sintering melt track based on machine vision, comprising: a host computer, and a powder spreading module, a vision monitoring module, a laser scanning module, and a compensation module connected to the host computer;

[0006] The powder spreading module includes a powder spreading device and a powder spreading platform, and the powder spreading device is used to spread powder on the powder spreading platform;

[0007] The laser scanning module is used to perform laser scanning on the powder on the powder spreading platform, and finally form a workpiece; a melt track is formed when the powder is laser scanned;

[0008] The visual monitoring module is arranged near the powder spreading platform, and is used to monitor the weld bead defects, powder spreading state, and weld bead compensation results respectively, and transmit the monitoring data to the host computer;

[0009] The compensation module is used to perform feeding and laser scanning repair on the area to be compensated according to the weld bead defect data fed back by the host computer.

[0010] Further, the powder spreading device includes a powder feeding system and a roller cart. The powder feeding system is used to provide the powder for laser scanning and transport the powder to the powder spreading platform; the roller cart is used to evenly spread the powder on the powder spreading platform, and the powder spreading platform is used to carry the powder to be laser scanned.

[0011] Further, the powder spreading module further includes a forming piston device. The powder spreading platform is arranged on the forming piston device, and the forming piston device is used to adjust the height of the powder spreading platform after each layer of laser scanning;

[0012] Further, the visual monitoring module includes a plurality of CCD cameras, which are distributed on both sides above the powder spreading platform.

[0013] Further, it further includes a light source module. The light source module includes a camera light source, and the camera light source is arranged on the CCD camera.

[0014] Further, the laser scanning module includes a laser device and a laser scanning system. The laser device is used to generate and emit a laser beam and transmit the laser beam to the laser scanning system; the laser scanning system is used to perform laser scanning on the powder on the powder spreading platform by using the laser beam.

[0015] Further, the compensation module includes a feeding extrusion mechanism, a semiconductor laser, and a galvanometer. The feeding extrusion mechanism is arranged near the powder spreading platform and is used to feed the weld bead defect area under the control of the host computer; the semiconductor laser is used to generate and emit a laser beam and transmit the laser beam to the galvanometer; the galvanometer is used to perform laser scanning on the weld bead defect area for feeding under the control of the host computer.

[0016] Further, the feeding extrusion mechanism includes a stepper motor, a motor fixing plate, a variable pitch screw, a flange Ⅰ, an extrusion barrel, a nozzle, a flange Ⅱ, a feeding flow pipe, and a coupling. The stepper motor is installed on the motor fixing plate. The output end of the stepper motor is connected to one end of the variable pitch screw through the coupling. The other end of the variable pitch screw is connected to one side of the extrusion barrel. The nozzle is connected to the other side of the extrusion barrel. The feeding flow pipe is connected to one side of the extrusion barrel and is close to the connection between the variable pitch screw and the extrusion barrel. A flange Ⅱ is connected to one side of the extrusion barrel, and the flange Ⅱ is connected to the flange Ⅰ.

[0017] Furthermore, the galvanometer scanner used is a laser galvanometer scanner.

[0018] The present invention also provides a working method for a selective laser sintering melt track defect monitoring and compensation device, including the following steps:

[0019] S1. Use a powder feeding system to convey powder for laser scanning to a powder spreading platform, and use a roller cart to evenly spread the powder on the powder spreading platform;

[0020] S2. The laser scanning system performs selective laser sintering according to the control of a host computer, and performs layer-by-layer laser scanning on the powder on the powder spreading platform; when laser scanning the powder, a melt track is formed;

[0021] S3. The vision monitoring module monitors the melt track in S2 and transmits the monitoring data back to the host computer; if no defect is detected in the monitored melt track, the next layer of laser scanning is performed; if a melt track defect is detected, a compensation instruction is generated based on the detected defect data and transmitted to the feeding and extrusion mechanism, semiconductor laser, and galvanometer scanner;

[0022] S4. After the compensation module receives the compensation instruction from the host computer, according to the compensation instruction, it performs compensation work on the part to be repaired on the powder spreading platform. The feeding and extrusion mechanism feeds the area to be compensated according to the defect data, and the semiconductor laser and galvanometer scanner perform compensated laser scanning on the feeding of the area to be compensated according to the defect data;

[0023] S5. After each compensation, the vision monitoring module monitors the compensation status and transmits the monitoring data back to the host computer;

[0024] S6. The host computer analyzes the monitoring data in S5. If the compensation is successful, repeat S2 to perform the next layer of selective laser sintering;

[0025] S7. Repeat S3 to S6 until the entire melt track is completely compensated.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The selective laser sintering melt track defect monitoring and compensation device and method based on machine vision provided by the present invention, through the integration of industrial cameras, image processing technology, and multi-sensor fusion technology, realizes the real-time monitoring and automatic detection of state information such as the molten pool, powder bed, and part forming surface during the selective laser sintering process. The system can timely detect and feedback defects in the melt track, such as pores, balling, warping, and spattering, etc., and reduce the scrap rate through automatic control, improving product quality. At the same time, the system reduces manual intervention, reduces the risk of operators, enhances the applicability of the device in different working environments, simplifies the operation process, is convenient for popularization and application, and provides strong support for the development of selective laser sintering technology.

[0028] Based on the above reasons, the present invention can be widely promoted in the fields such as additive manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of the device of the present invention.

[0031] Figure 2 It is a schematic structural diagram of the feeding and extrusion mechanism of the present invention.

[0032] In the figure: 1. Laser device; 2. Laser scanning system; 3. Camera light source; 4. CCD camera; 5. Semiconductor laser; 6. Host computer; 7. Forming piston device; 8. Powder feeding system; 9. Roller car; 10. Galvo scanner; 11. Powder spreading platform; 12. Feeding and extrusion mechanism; 12.1. Stepper motor; 12.2. Motor fixing plate; 12.3. Variable pitch screw; 12.4. Flange Ⅰ; 12.5. Extrusion barrel; 12.6. Nozzle; 12.7. Flange Ⅱ; 12.8. Inlet flow pipe; 12.9. Coupling. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The following will refer to the drawings and combine with the embodiments to detail the present invention.

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restrictive of the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0035] It should be noted that the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly dictates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0036] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not require further discussion in subsequent drawings.

[0037] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present invention: the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0038] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper", etc. can be used here to describe the spatial positional relationship of a device or feature shown in the figure with other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the figure of the device. For example, if the device in the attached drawing is inverted, the device described as "above or over other devices or structures" will then be positioned "below or under other devices or structures". Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding interpretations are made for the spatial relative descriptions used here.

[0039] In addition, it should be noted that the use of terms such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the protection scope of the present invention.

[0040] Embodiment 1

[0041] The present invention provides a selective laser sintering melt track defect monitoring and compensation device based on machine vision, including: a host computer 6 and a powder spreading module, a vision monitoring module, a laser scanning module, a light source module, and a compensation module (defect compensation module) electrically connected to the host computer 6.

[0042] The powder spreading module includes a forming piston device 7, a powder feeding system 8, a roller car 9, and a powder spreading platform 11. The powder feeding system 8 is used to supply the powder for laser scanning and transport the powder to the powder spreading platform 11; the roller car 9 is used to evenly spread the powder on the powder spreading platform 11, and the powder spreading platform 11 is used to carry the powder to be laser scanned; the powder spreading platform 11 is arranged on the forming piston device 7, and the forming piston device 7 is used to adjust the height of the powder spreading platform 11 after each layer of laser scanning.

[0043] The laser scanning module is used to scan the powder platform to form a workpiece: under the control of the host computer 6, it is used to adjust the laser scanning system 2 to perform laser scanning on the powder. When laser scanning the powder, a melt track is formed. The laser scanning module includes a laser device 1 and a laser scanning system 2. The laser device 1 is used to generate and emit a laser beam and transmit the laser beam to the laser scanning system 2; the laser scanning system 2 is used to perform laser scanning on the powder on the powder spreading platform 11 using the laser beam.

[0044] The visual monitoring module includes multiple CCD cameras 4 close to the powder spreading platform 11. The multiple CCD cameras 4 are distributed on both sides above the powder spreading platform 11, and image acquisition of the melting track is performed through the CCD cameras 4. In this embodiment, there are two CCD cameras 4. The visual monitoring module is used to monitor the melting track defects, powder spreading state, and melting track compensation results respectively, and upload the monitoring data back to the host computer 6; it includes: being used to monitor the melting track and transmit the melting track data with defects (including defect type, contour data, defect position) back to the host computer 6; being used to monitor the powder spreading state after each powder spreading and transmit the monitoring data back to the host computer 6; being used to monitor the compensation result after each laser compensation and transmit the monitoring data back to the host computer 6.

[0045] The light source module includes a camera light source 3 arranged on the CCD camera 4, which plays an illuminating role, is used to improve the quality of the acquired image, and at the same time improve the accuracy and reliability of the system.

[0046] The compensation module includes a feeding extrusion mechanism 12, a semiconductor laser 5, and a galvanometer scanner 10. According to the defect information fed back by the host computer 6, feeding and laser scanning repair processing are performed on the area to be compensated. The feeding extrusion mechanism 12 is arranged close to the powder spreading platform 11 and is used to feed the melting track defect area under the control of the host computer 6; the semiconductor laser 5 and the galvanometer scanner 10 are used to perform laser scanning for feeding the melting track defect area under the control of the host computer 6. Among them, the semiconductor laser 5 is used to generate and emit a laser beam and transmit the laser beam to the galvanometer scanner 10. The galvanometer scanner 10 is used to perform laser scanning for feeding the melting track defect area with the laser beam under the control of the host computer 6. Preferably, the galvanometer scanner 10 uses a laser galvanometer scanner.

[0047] Preferably, the feeding extrusion mechanism 12 includes a stepper motor 12.1, a motor fixing plate 12.2, a variable pitch screw 12.3, a flange Ⅰ 12.4, an extrusion barrel 12.5, a nozzle 12.6, a flange Ⅱ 12.7, a feeding flow pipe 12.8, and a coupling 12.9. The stepper motor 12.1 is installed on the motor fixing plate 12.2. The output end of the stepper motor 12.1 is connected to one end of the variable pitch screw 12.3 through the coupling 12.9. The other end of the variable pitch screw 12.3 is connected to one side of the extrusion barrel 12.5. The nozzle 12.6 is connected to the other side of the extrusion barrel 12.5. The feeding flow pipe 12.8 is connected to one side of the extrusion barrel 12.5 and is close to the connection part of the variable pitch screw 12.3 and the extrusion barrel 12.5. A flange Ⅱ 12.7 is connected to one side of the extrusion barrel 12.5, and the flange Ⅱ 12.7 is connected to the flange Ⅰ 12.4. The stepper motor 12.1 uses a 42 series two-phase hybrid stepper motor, and the coupling 12.9 uses a LYCA plum blossom coupling.

[0048] Specifically, the stepper motor 12.1 is used to control the rotation of the variable pitch screw 12.3. The motor fixing plate 12.2 is used to fix the stepper motor 12.1 to the XY lead screw motor of the feeding and extrusion mechanism 12 (not shown in the figure). The variable pitch screw 12.3 is used to convey the metal powder for feeding in the extrusion barrel 12.5 to the nozzle 12.6. The flange plate I 12.4 is used to fix the extrusion barrel 12.5 to the XY lead screw motor of the feeding and extrusion mechanism 12. The extrusion barrel 12.5 is used to store the metal powder conveyed by the feeding flow pipe 12.8. The nozzle 12.6 is used to extrude the metal powder. The flange plate II 12.7 is used to fix the flange plate I 12.4 and the extrusion barrel 12.5. The feeding flow pipe 12.8 is used to convey the metal powder required by the feeding and extrusion mechanism 12 to the extrusion barrel 12.5. The coupling 12.9 is used to connect the output end lead screw of the stepper motor 12.1 and the variable pitch screw 12.3.

[0049] The present invention adopts the selective laser sintering technology and the machine vision technology to realize the monitoring and compensation of the melt channel defects in the metal printing process, with higher precision, better forming structure performance in additive manufacturing, and meeting the manufacturing of more complex structures.

[0050] Embodiment 2

[0051] The present invention also provides a working method for a device for monitoring and compensating melt channel defects in selective laser sintering based on machine vision, including the following steps:

[0052] S1. The powder feeding system 8 conveys the powder for laser scanning to the powder spreading platform 11, and the roller cart 9 is used to evenly spread the powder on the powder spreading platform 11.

[0053] S2. The laser scanning system 2 performs selective laser sintering according to the control of the host computer 6, and performs layer-by-layer laser scanning on the powder on the powder spreading platform 11; a melt channel is formed when the powder is laser scanned.

[0054] S3. The vision monitoring module monitors the melt channel in S2 and transmits the monitoring data back to the host computer 6. If no defect is detected in the monitored melt channel, the next layer of laser scanning is performed. If a defect in the melt channel is detected, a compensation instruction is generated based on the detected defect data and transmitted to the feeding and extrusion mechanism 12, the semiconductor laser 5, and the galvanometer 10.

[0055] S4. After the compensation module receives the compensation instruction from the host computer 6, according to the compensation instruction, it performs compensation work on the part to be repaired on the powder spreading platform 11. The feeding and extrusion mechanism 12 feeds the area to be compensated according to the defect data, and the semiconductor laser 5 and the galvanometer 10 perform compensated laser scanning on the feed of the area to be compensated according to the defect data.

[0056] S5. After each compensation, the vision monitoring module monitors the compensation status and transmits the monitoring data back to the host computer 6.

[0057] S6. The host computer 6 analyzes the monitoring data in S5. If the compensation is successful, repeat S2 to perform the next layer of selective laser sintering.

[0058] S7. Repeat S3 to S6 until the entire melt channel is completely compensated.

[0059] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A selective laser sintering melt defect monitoring and compensation device based on machine vision, characterized in that: include: A host computer (6) and a powder spreading module, a visual monitoring module, a laser scanning module and a compensation module connected to the host computer (6); The powder spreading module comprises a powder spreading device and a powder spreading platform (11), wherein the powder spreading device is used to spread powder on the powder spreading platform (11); The laser scanning module is used to perform laser scanning on the powder on the powder spreading platform (11), and finally form the workpiece; a melt path is formed when the laser scans the powder; The visual monitoring module is arranged at a position close to the powder spreading platform (11), and is used to monitor the melt channel defects, the powder spreading state, and the melt channel compensation results, and transmit the monitoring data to the host computer (6); The compensation module is used to perform material filling and laser scanning repair processing on the area to be compensated according to the melt defect data fed back by the host computer (6).

2. The selective laser sintering melt defect monitoring and compensation device based on machine vision according to claim 1 is characterized in that: The powder spreading device comprises a powder feeding system (8) and a roller (9), wherein the powder feeding system (8) is used to provide powder for laser scanning and transport the powder to a powder spreading platform (11); the roller (9) is used to evenly spread the powder on the powder spreading platform (11), and the powder spreading platform (11) is used to carry the powder to be laser scanned.

3. The selective laser sintering melt defect monitoring and compensation device based on machine vision according to claim 1 or 2, characterized in that: The powder spreading module further comprises a forming piston device (7), the powder spreading platform (11) is arranged on the forming piston device (7), and the forming piston device (7) is used to adjust the height of the powder spreading platform (11) after each layer of laser scanning.

4. The selective laser sintering melt defect monitoring and compensation device based on machine vision according to claim 1 is characterized in that: The visual monitoring module comprises a plurality of CCD cameras (4) which are distributed on both sides above the powder spreading platform (11).

5. The selective laser sintering melt defect monitoring and compensation device based on machine vision according to claim 4 is characterized in that: It also comprises a light source module, the light source module comprises a camera light source (3), and the camera light source (3) is arranged on a CCD camera (4).

6. The selective laser sintering melt defect monitoring and compensation device based on machine vision according to claim 1 is characterized in that: The laser scanning module comprises a laser device (1) and a laser scanning system (2); the laser device (1) is used to generate and emit a laser beam and transmit the laser beam to the laser scanning system (2); the laser scanning system (2) is used to perform laser scanning on the powder on the powder spreading platform (11) using the laser beam.

7. The selective laser sintering melt defect monitoring and compensation device based on machine vision according to claim 1 is characterized in that: The compensation module comprises a material filling extrusion mechanism (12), a semiconductor laser (5) and a galvanometer (10); the material filling extrusion mechanism (12) is arranged at a position close to the powder spreading platform (11) and is used to fill the melt defect area with material under the control of the host computer (6); the semiconductor laser (5) is used to generate and emit a laser beam and transmit the laser beam to the galvanometer (10); the galvanometer (10) is used to perform laser scanning on the melt defect area for filling with material using the laser beam under the control of the host computer (6).

8. The selective laser sintering melt defect monitoring and compensation device based on machine vision according to claim 7 is characterized in that: The feeding extrusion mechanism (12) comprises a stepper motor (12.1), a motor fixing plate (12.2), a variable pitch screw (12.3), a flange I (12.4), an extrusion barrel (12.5), a nozzle (12.6), a flange II (12.7), an inlet flow pipe (12.8) and a coupling (12.9). The stepper motor (12.1) is mounted on the motor fixing plate (12.2). The output end of the stepper motor (12.1) is connected to the variable pitch screw (12.3) via the coupling (12.9). ), the other end of the variable pitch screw (12.3) is connected to one side of the extrusion barrel (12.5), the nozzle (12.6) is connected to the other side of the extrusion barrel (12.5), the inlet flow pipe (12.8) is connected to one side of the extrusion barrel (12.5) and is close to the connection between the variable pitch screw (12.3) and the extrusion barrel (12.5), one side of the extrusion barrel (12.5) is connected to a flange II (12.7), and the flange II (12.7) is connected to a flange I (12.4).

9. The selective laser sintering melt defect monitoring and compensation device based on machine vision according to claim 7, characterized in that: The galvanometer (10) is a laser galvanometer.

10. A working method of the selective laser sintering melt defect monitoring and compensation device according to any one of claims 1 to 9, characterized in that: The steps include: S1, conveying powder for laser scanning to a powder spreading platform (11) through a powder feeding system (8), and spreading the powder evenly on the powder spreading platform (11) using a roller (9); S2, the laser scanning system (2) performs selective laser sintering according to the control of the host computer (6), and performs laser scanning on the powder on the powder spreading platform (11) layer by layer; a melt path is formed when the laser scans the powder; S3, the visual monitoring module monitors the melt path in S2 and transmits the monitoring data back to the host computer (6); if the monitored melt path is free of defects, the next layer of laser scanning is performed; if a melt path defect is detected, a compensation instruction is generated based on the monitored defect data and transmitted to the feeding extrusion mechanism (12), the semiconductor laser (5) and the galvanometer (10); S4, after receiving the compensation instruction from the host computer (6), the compensation module performs compensation work on the parts to be repaired on the powder spreading platform (11) according to the compensation instruction, the material filling extrusion mechanism (12) fills the area to be compensated according to the defect data, and the semiconductor laser (5) and the galvanometer (10) perform compensation laser scanning on the material filling area to be compensated according to the defect data; S5. After each compensation, the visual monitoring module monitors the compensation status and transmits the monitoring data back to the host computer (6); S6, the host computer (6) analyzes the monitoring data in S5, and if the compensation is successful, repeats S2 to perform the next layer of selective laser sintering; S7, repeat S3 to S6 until the entire melt path is fully compensated.

Images