Molten pool monitoring device

Abstract

The utility model belongs to the field of additive manufacturing, and relates to a molten pool monitoring device which comprises an imager sealing mechanism, a monitoring device packaging mechanism, an infrared imager and a focus lens. The imager sealing mechanism and the monitoring device packaging mechanism are both of a hollow cylindrical structure. The infrared imager is arranged in the imager sealing mechanism; the focus lens is arranged in the monitoring device packaging mechanism; the imager sealing mechanism is connected with the monitoring device packaging mechanism; the focus lens and the infrared imager are sequentially arranged on the same light path from front to back. The utility model provides the molten pool monitoring device which is convenient for real-time monitoring and ensures the forming quality.

Description

Technical Field

[0001] This utility model belongs to the field of additive manufacturing and relates to a molten pool monitoring device, and more particularly to a molten pool monitoring device for laser energy directional deposition. Background Technology

[0002] Laser cladding additive manufacturing technology, as a cutting-edge technology in modern materials processing and manufacturing, is gradually becoming a key means to improve material surface properties, repair, and remanufacturing due to its unique advantages of high precision, high efficiency, low dilution rate, and ability to directly form complex-shaped parts. It is currently widely used in high-end manufacturing fields such as aerospace, automotive, and energy. However, in actual production, laser cladding additive manufacturing technology also faces many challenges. Dynamic changes in substrate shape, temperature, material, and thermal conductivity, as well as fluctuations in process parameters during cladding, can lead to uneven heating at the cladding interface, and significant instability in the shape, size, and temperature of the molten pool. The combined effect of these problems may cause uncontrolled height and width of the deposited material, or even prevent forming altogether. Currently, industry monitoring of the forming process still relies mainly on manual inspection, which is inefficient and makes it difficult to capture the dynamic changes of the molten pool in real time. Therefore, researching automated and intelligent molten pool monitoring systems is of practical significance. Utility Model Content

[0003] In order to solve the above-mentioned technical problems in the background art, the present invention provides a molten pool monitoring device that facilitates real-time monitoring and ensures forming quality.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A molten pool monitoring device, characterized in that: the molten pool monitoring device includes an imager sealing mechanism, a monitoring device packaging mechanism, an infrared imager, an aperture, and a focusing lens; both the imager sealing mechanism and the monitoring device packaging mechanism are hollow cylindrical structures; the infrared imager is placed inside the imager sealing mechanism; the aperture and the focusing lens are disposed inside the monitoring device packaging mechanism; the imager sealing mechanism is connected to the monitoring device packaging mechanism; the aperture, the focusing lens, and the infrared imager are arranged sequentially from front to back on the same optical path.

[0006] The aforementioned molten pool monitoring device also includes a focusing lens fixing mechanism disposed inside the monitoring device packaging mechanism; the focusing lens is disposed radially inside the monitoring device packaging mechanism via the focusing lens fixing mechanism.

[0007] The aforementioned focusing lens fixing mechanism includes a lens clamping ring and a lens contact ring; both the lens clamping ring and the lens contact ring are radially arranged inside the monitoring device packaging mechanism; the focusing lens is placed between the lens clamping ring and the lens contact ring.

[0008] The aforementioned lens contact ring makes contact with the focusing lens line or surface.

[0009] The aforementioned molten pool monitoring device also includes an aperture fixing mechanism disposed inside the monitoring device packaging mechanism. The aperture is disposed radially inside the monitoring device packaging mechanism via the aperture fixing mechanism.

[0010] The aforementioned aperture fixing mechanism is an aperture clamping ring; the aperture clamping ring squeezes the aperture and sets the aperture inside the monitoring device encapsulation mechanism.

[0011] The aforementioned monitoring device packaging mechanism is an L-shaped hollow cylindrical structure; the molten pool monitoring device also includes a reflector disposed inside the monitoring device packaging mechanism; the aperture, reflector, focusing lens and infrared imager are arranged sequentially from front to back on the same optical path.

[0012] The aforementioned molten pool monitoring device also includes a reflector angle adjustment mechanism disposed inside the monitoring device packaging mechanism; the reflector is disposed inside the monitoring device packaging mechanism via the reflector angle adjustment mechanism; the reflector angle adjustment mechanism drives the reflector to adjust its angle.

[0013] The aforementioned molten pool monitoring device also includes a focal length adjustment mechanism disposed between the imager sealing mechanism and the monitoring device packaging mechanism.

[0014] The aforementioned focus adjustment mechanism includes a lens barrel fixing seat, a telescopic lens barrel, and a set screw; the lens barrel fixing seat is fitted onto the outside of the telescopic lens barrel and moves along the axial direction of the telescopic lens barrel; the set screw passes through the lens barrel fixing seat and extends into the telescopic lens barrel; a sealing ring is provided between the lens barrel fixing seat and the telescopic lens barrel; the lens barrel fixing seat is connected to the imaging instrument sealing mechanism; and the telescopic lens barrel is connected to the monitoring device encapsulation mechanism.

[0015] The aforementioned imager sealing mechanism includes a reserved through-plate sealing connector; the infrared imager and the two inner wall planes of the imaging sealing mechanism are tightly connected, one of which is fastened to the imager sealing mechanism by screws; a sealing ring is provided between the infrared imager and the imager sealing mechanism; the wiring harness of the infrared imager is led out of the imager sealing mechanism through the aforementioned through-plate sealing connector.

[0016] A laser cladding additive manufacturing apparatus based on the aforementioned molten pool monitoring device is characterized in that: the laser cladding additive manufacturing apparatus includes a laser forming device, a control system, and a molten pool monitoring device; the laser forming device includes a laser, a collimating lens, a beam splitter, and a focusing lens; a forming laser is emitted from the laser; the collimating lens, beam splitter, and focusing lens are sequentially arranged in the optical path of the forming laser from front to back; the forming laser enters the forming origin and melts the powder to form a molten pool; the reflected light from the molten pool passes through the focusing lens and beam splitter in sequence before entering the molten pool monitoring device; the control system is connected to both the laser and the molten pool monitoring device.

[0017] The advantages of this utility model are:

[0018] This invention provides a molten pool monitoring device, including an imager sealing mechanism, a monitoring device encapsulation mechanism, an infrared imager, an aperture, and a focusing lens. Both the imager sealing mechanism and the monitoring device encapsulation mechanism are hollow cylindrical structures. The infrared imager is placed inside the imager sealing mechanism. The aperture and focusing lens are located inside the monitoring device encapsulation mechanism. The imager sealing mechanism is connected to the monitoring device encapsulation mechanism. The aperture, focusing lens, and infrared imager are arranged sequentially from front to back on the same optical path. This invention achieves fault diagnosis and analysis of the printing process by capturing the molten pool characteristics during the laser energy directional deposition process in real time, and realizing quality analysis and laser parameter closed-loop control through a control system. This invention obtains effective molten pool temperature information through an infrared thermal imager and visualizes it as an accurate molten pool image. Simultaneously, based on image processing algorithms, multi-dimensional molten pool size parameters can be calculated, fully combined with printing process parameters, to intuitively visualize the molten pool parameters and achieve real-time monitoring. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the molten pool monitoring device provided by this utility model;

[0020] Figure 2 This is a schematic diagram of the focal length adjustment mechanism used in this utility model;

[0021] Figure 3 This is a schematic diagram of the focusing lens fixing mechanism used in this utility model;

[0022] Figure 4 This is a schematic diagram of the reflector angle adjustment mechanism used in this utility model;

[0023] Figure 5 This is a schematic diagram of the aperture fixing mechanism used in this utility model;

[0024] Figure 6This is a schematic diagram of the packaging mechanism of the monitoring device used in this utility model;

[0025] Figure 7 This is a schematic diagram of the focal length adjustment mechanism used in this utility model under different focal length conditions;

[0026] Figure 8 This is a schematic diagram of the molten pool monitoring device provided by this utility model in use;

[0027] Figure 9 This is a schematic diagram of the imaging device sealing mechanism used in this utility model;

[0028] in:

[0029] 1-Imaging instrument sealing mechanism; 2-Infrared imager; 3-Focus adjustment mechanism; 31-Lens barrel fixing base; 32-Telescopic lens barrel; 33-Sealing ring; 4-Focusing lens fixing mechanism; 41-Lens clamping ring; 42-Lens contact ring; 5-Focusing lens; 6-Reflector angle adjustment mechanism; 7-Reflector; 8-Aperture stop fixing mechanism; 81-Aperture stop clamping ring; 9-Aperture stop; 10-Monitoring device packaging mechanism; 11-Monitoring device connection mechanism; 12-Control system. Detailed Implementation

[0030] See Figure 1 This invention provides a molten pool monitoring device, comprising an imager sealing mechanism 1, a monitoring device encapsulation mechanism 10, an infrared imager 2, an aperture 9, and a focusing lens 5. Both the imager sealing mechanism 1 and the monitoring device encapsulation mechanism 10 are hollow cylindrical structures. The infrared imager 2 is housed inside the imager sealing mechanism 1. The aperture 9 and the focusing lens 5 are located inside the monitoring device encapsulation mechanism 10. The imager sealing mechanism 1 is connected to the monitoring device encapsulation mechanism 10. The aperture 9, the focusing lens 5, and the infrared imager 2 are arranged sequentially along the same optical path from front to back. In use, the infrared spectrum generated during the molten pool's operation passes sequentially through the aperture 9 and the focusing lens 5, and is then detected and monitored by the infrared imager 2, ultimately achieving real-time monitoring of the molten pool's operating status.

[0031] See Figure 1 as well as Figure 3 The molten pool monitoring device provided by this utility model also includes a focusing lens fixing mechanism 4 disposed inside the monitoring device packaging mechanism 10; the focusing lens 5 is disposed radially inside the monitoring device packaging mechanism 10 via the focusing lens fixing mechanism 4. The key to the focusing lens 5 is to use a reasonable focal length to ensure a moderate field of view for shooting, while maintaining a high transmittance for near-infrared light. See also Figure 3The focusing lens fixing mechanism 4 includes a lens clamping ring 41 and a lens contact ring 42. Both the lens clamping ring 41 and the lens contact ring 42 are radially disposed inside the monitoring device packaging mechanism 10. The focusing lens 5 is placed between the lens clamping ring 41 and the lens contact ring 42. For example, a groove and threads are provided inside the monitoring device packaging mechanism 10. The lens contact ring 42 is placed in the groove, and the lens clamping ring 41 is threadedly connected to the inner wall of the monitoring device packaging mechanism 10. Since the focusing lens 5 is placed between the lens clamping ring 41 and the lens contact ring 42, when the lens clamping ring 41 is turned, the focusing lens 5 is firmly and stably placed radially inside the monitoring device packaging mechanism 10. For example, besides the lens clamping ring 41 being threadedly connected to the monitoring device packaging mechanism 10, it can also be snap-fitted, inserted by an external set screw, or any commonly used connection method in the prior art, as long as the two can be fixed. Further details are omitted here. See [link to relevant documentation]. Figure 3 The lens contact ring 42 and the focusing lens 5 are in line contact or surface contact. Surface contact means that the contact area between the lens contact ring 42 and the focusing lens 5 is larger, which is less likely to scratch the surface of the focusing lens 5 and is the preferred method. The lens clamping ring 41 evenly distributes the clamping force on the focusing lens, ensuring that the focusing lens is safely and stably connected to the monitoring packaging mechanism.

[0032] See Figure 1 as well as Figure 5 The molten pool monitoring device provided by this utility model further includes an aperture fixing mechanism 8 disposed inside the monitoring device packaging mechanism 10. The aperture 9 is disposed radially inside the monitoring device packaging mechanism 10 via the aperture fixing mechanism 8. For example, the aperture fixing mechanism 8 is an aperture clamping ring 81; the aperture clamping ring 81 presses the aperture 9 and positions it inside the monitoring device packaging mechanism 10. For example, a thread is provided on the inner wall of the monitoring device packaging mechanism 10, and the aperture clamping ring 81 is threadedly connected to the monitoring device packaging mechanism 10.

[0033] The monitoring device packaging mechanism 10 can be a hollow cylindrical structure in a straight line. When it is in a straight line, it will prolong the spatial structure of the entire molten pool monitoring device. To improve this situation, see [reference needed]. Figure 1 as well as Figure 6 The monitoring device packaging mechanism 10 used in this utility model is generally L-shaped. To adapt the infrared monitoring optical path, the molten pool monitoring device provided by this utility model also includes a reflector 7 disposed inside the monitoring device packaging mechanism 10. The aperture 9, reflector 7, focusing lens 5, and infrared imager 2 are arranged sequentially from front to back on the same optical path. For convenient adjustment of the angle of the reflector 7, see [reference needed]. Figure 1 as well as Figure 4The molten pool monitoring device provided by this utility model also includes a reflector angle adjustment mechanism 6 disposed inside the monitoring device packaging mechanism 10; the reflector 7 is disposed inside the monitoring device packaging mechanism 10 via the reflector angle adjustment mechanism 6; the reflector angle adjustment mechanism 6 drives the reflector 7 to adjust its angle. For example, the reflector 7 can change the direction of the incident light so that it perpendicularly enters the target surface of the infrared imager 2, see [reference needed]. Figure 4 Four set screws, located at different positions in the reflector angle adjustment mechanism 6, extend from the reflector angle adjustment mechanism 6 and rest against the bottom of the reflector 7. By adjusting different set screws, the angle of the reflector 7 can be slightly changed, thereby ensuring the concentricity of the light and the infrared imager 2, so that the molten pool area is located in the center of the image of the infrared imager 2.

[0034] See Figure 1 as well as Figure 2 The molten pool monitoring device provided by this utility model also includes a focal length adjustment mechanism 3 disposed between the imager sealing mechanism 1 and the monitoring device packaging mechanism 10. To meet the imaging requirements of different focal length ranges, the focal length adjustment mechanism 3 covers the focal length ranges of various focusing lenses by adjusting the longitudinal dimension of the lens barrel, thereby achieving stable multi-focal length range monitoring of the molten pool coaxial monitoring device. Figure 7 As shown in (a) and (b), these correspond to long and short focal lengths, respectively.

[0035] The process of obtaining the focal length of the imaging focusing lens in this solution is as follows:

[0036]

[0037] in:

[0038] FOV is the target field of view, S is the thermal imager target size, and F... 激光 This is the focal length of the laser focusing lens in the coaxial optical path. The imaging focusing lens is made of K9 optical glass, which features wide spectral transmittance. The focusing adjustment mechanism achieves focusing by adjusting the extension and retraction of the upper and lower sleeves, thereby changing the distance between the thermal imager target surface and the focusing lens.

[0039] For example, see Figure 2The focal length adjustment mechanism 3 used in this invention includes a lens barrel fixing seat 31, a telescopic lens barrel 32, and set screws. The lens barrel fixing seat 31 is fitted onto the outside of the telescopic lens barrel 32 and moves along the axial direction of the telescopic lens barrel 32. The set screw passes through the lens barrel fixing seat 31 and extends towards the telescopic lens barrel 32. A sealing ring 33 is provided between the lens barrel fixing seat 31 and the telescopic lens barrel 32. Of course, other sealing rings can also be used in this invention to form a dustproof and sealed structure. The lens barrel fixing seat 31 is connected to the imager sealing mechanism 1. The telescopic lens barrel 32 is connected to the monitoring device encapsulation mechanism 10. There can be three set screws, which are evenly distributed on the lens barrel fixing seat 31. After the relative positions of the lens barrel fixing seat 31 and the telescopic lens barrel 32 are adjusted, the lens barrel fixing seat 31 and the telescopic lens barrel 32 can be stably connected. For example, the upper part of the focal length adjustment mechanism 3 is connected to the upper imager sealing mechanism 1 through a rubber sealing ring, and its lower part is connected to the monitoring device encapsulation mechanism 10 through a sealing ring.

[0040] See Figure 8 This is a structural diagram of the present invention in specific use. The molten pool monitoring device provided by the present invention is integrated into the laser directional energy deposition equipment via a monitoring device connecting mechanism 11 (exemplarily, the monitoring device connecting mechanism 11 is connected to the laser directional energy deposition equipment and the monitoring device encapsulation mechanism 10 through sealing rings for dustproof sealing). The control system 12 is the control system of the equipment, which, in addition to the integrated control functions of the printing equipment, also integrates optical control and a thermal imaging information acquisition and analysis system. Through the molten pool monitoring device, the characteristics of the molten pool are monitored in real time during the laser energy directional deposition process.

[0041] See Figure 1 as well as Figure 9The molten pool monitoring device provided by this utility model uses an imager sealing mechanism to achieve dustproof sealing of the connecting harness and focus adjustment mechanism 3 used by the infrared imager 2, and assists the infrared imager 2 in heat dissipation. In use, the connecting harness of the infrared imager 2 is led out from the two pre-reserved through-plate sealing ports of the imager sealing mechanism, and a dustproof insert structure is used for through-plate sealing; the main body of the infrared imager 2 is fastened to the imager sealing mechanism 1 through a pre-reserved threaded hole, and a rubber sealing ring is used in the sealing ring groove outside the pre-reserved threaded hole for dust prevention. Exemplarily, the side wall of the imager sealing mechanism 1 is provided with a fastening device for fixing the infrared imager 2, such as a set screw or a screw, which penetrates the side wall of the imager sealing mechanism 1 and presses against the infrared imager 2. The infrared imager 2 and the imager sealing mechanism 1 are screwed into the lens barrel fixing seat 31 in the focus adjustment mechanism 3 through the standard thread of the infrared imager 2. When the reserved hole of the imager sealing mechanism 1 is aligned with the reserved threaded hole of the lens barrel fixing seat 31, and tightening it again cannot align the hole, screws are used to fasten the entire infrared imager 2 and the lens barrel fixing seat 31 to the imager sealing mechanism 1, and a rubber sealing ring is used in the reserved sealing groove to seal the thermal imager 2 for dust prevention.

[0042] The focal length adjustment mechanism 3 is concentrically and positionally adjusted by multiple set screws, and its height is adjusted by the lens barrel fixing seat 31 and the telescopic lens barrel 32 nested therein. The focal length adjustment system is dustproof and sealed by the plug 33 in the tightly nested lens barrel fixing seat 31 and the sealing ring on the side of the lens barrel fixing seat 31 connected to the imaging instrument sealing mechanism, so as to ensure the life and stability of the focal length adjustment mechanism 3.

[0043] See Figure 8 This invention provides a molten pool monitoring device and a laser cladding additive manufacturing device based on the molten pool monitoring device. The laser cladding additive manufacturing device includes a laser forming device, a control system 12, and a molten pool monitoring device. The laser forming device melts powder to form a molten pool, and the reflected light from the molten pool passes through the laser forming device and is then incident on the molten pool monitoring device. The control system 12 is connected to both the laser forming device and the molten pool monitoring device. See also... Figure 8 For example, the laser forming device may include a laser, a collimating lens, a beam splitter, and a focusing lens; the laser emits a forming laser; the collimating lens, beam splitter, and focusing lens are arranged sequentially from front to back in the optical path of the forming laser; the forming laser enters the forming area and melts the powder to form a molten pool; the reflected light from the molten pool passes through the focusing lens and beam splitter in sequence before entering the molten pool monitoring device. It should be noted that the control system 12 can be any conventional controller used to control the parameter settings, start and stop of the laser, and to control the real-time monitoring of the infrared imager 2. For example, a programmable logic controller (PLC) or other commonly used controllers can be used. Commercially available products are used in this invention, and will not be described further.

[0044] In practical use, the molten pool monitoring device provided by this invention first sets the initial molten pool size. After installation and debugging, the device is moved to the printing origin. A single-pass test is performed according to the material and process parameters required for the printed part, measuring the width of the solidified molten pool. The target surface size S of the thermal imager is adjusted based on the measured molten pool width to ensure that the collected molten pool area is relatively consistent with the actual molten pool size. Subsequently, the printing program is run, and the forming laser melts the powder to form a molten pool. The light emitted by the molten pool at a characteristic wavelength enters the thermal imager, forming molten pool data. This data is transmitted to the control system in real time for data processing and analysis. Finally, the molten pool monitoring device provided by this invention transmits the molten pool information to the control system 12 in real time. The control system 12 processes and analyzes the data, provides real-time feedback on optical parameters, and performs real-time diagnosis of anomalies to ensure the continuity of printing.

Claims

1. A molten pool monitoring device, characterized in that: The molten pool monitoring device includes an imager sealing mechanism (1), a monitoring device packaging mechanism (10), an infrared imager (2), and a focusing lens (5); the imager sealing mechanism (1) and the monitoring device packaging mechanism (10) are both hollow cylindrical structures; the infrared imager (2) is placed inside the imager sealing mechanism (1); the focusing lens (5) is set inside the monitoring device packaging mechanism (10); the imager sealing mechanism (1) is connected to the monitoring device packaging mechanism (10); the focusing lens (5) and the infrared imager (2) are arranged sequentially from front to back on the same optical path.

2. The molten pool monitoring device according to claim 1, characterized in that: The molten pool monitoring device also includes a focusing lens fixing mechanism (4) disposed inside the monitoring device packaging mechanism (10); the focusing lens (5) is disposed inside the monitoring device packaging mechanism (10) along the radial direction of the monitoring device packaging mechanism (10) via the focusing lens fixing mechanism (4).

3. The molten pool monitoring device according to claim 2, characterized in that: The focusing lens fixing mechanism (4) includes a lens clamping ring (41) and a lens contact ring (42); the lens clamping ring (41) and the lens contact ring (42) are both radially arranged inside the monitoring device packaging mechanism (10) along the monitoring device packaging mechanism (10); the focusing lens (5) is placed between the lens clamping ring (41) and the lens contact ring (42).

4. The molten pool monitoring device according to claim 3, characterized in that: The lens contact ring (42) is in line contact or surface contact with the focusing lens (5).

5. The molten pool monitoring device according to claim 4, characterized in that: The molten pool monitoring device also includes an aperture fixing mechanism (8) and an aperture (9). The aperture (9) is arranged radially inside the monitoring device packaging mechanism (10) via the aperture fixing mechanism (8).

6. The molten pool monitoring device according to any one of claims 1-5, characterized in that: The monitoring device packaging mechanism (10) is an L-shaped hollow cylindrical structure; the molten pool monitoring device also includes a reflector (7) disposed inside the monitoring device packaging mechanism (10); the reflector (7), the focusing lens (5) and the infrared imager (2) are arranged sequentially from front to back on the same optical path.

7. The molten pool monitoring device according to claim 6, characterized in that: The molten pool monitoring device also includes a reflector angle adjustment mechanism (6) disposed inside the monitoring device packaging mechanism (10); the reflector (7) is disposed inside the monitoring device packaging mechanism (10) through the reflector angle adjustment mechanism (6); the reflector angle adjustment mechanism (6) drives the reflector (7) to adjust its angle.

8. The molten pool monitoring device according to claim 7, characterized in that: The molten pool monitoring device also includes a focal length adjustment mechanism (3) disposed between the imager sealing mechanism (1) and the monitoring device packaging mechanism (10). The focal length adjustment mechanism (3) includes a lens barrel fixing seat (31), a telescopic lens barrel (32), and a set screw. The lens barrel fixing seat (31) is fitted outside the telescopic lens barrel (32) and moves along the axial direction of the telescopic lens barrel (32). The set screw passes through the lens barrel fixing seat (31) and extends toward the telescopic lens barrel (32). A sealing ring (33) is provided between the lens barrel fixing seat (31) and the telescopic lens barrel (32). The lens barrel fixing seat (31) is connected to the imager sealing mechanism (1). The telescopic lens barrel (32) is connected to the monitoring device packaging mechanism (10).

9. The molten pool monitoring device according to claim 8, characterized in that: The upper part of the imager sealing mechanism (1) is provided with a reserved through-plate sealing insertion interface; a sealing ring is provided between the infrared imager (2) and the imager sealing mechanism (1); a fastening device for fixing the infrared imager (2) is provided on the side wall of the imager sealing mechanism (1).

10. A laser cladding additive manufacturing apparatus based on the molten pool monitoring device as described in any one of claims 1-9, characterized in that: The laser cladding additive manufacturing device includes a laser forming device, a control system (12), and a molten pool monitoring device as described in any one of claims 1-9; the laser forming device melts powder to form a molten pool; the reflected light formed by the molten pool is incident on the molten pool monitoring device after passing through the laser forming device; the control system (12) is connected to the laser forming device and the molten pool monitoring device respectively.

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