Metal additive manufacturing molten pool acoustic emission in-situ detection module

Abstract

The invention discloses a metal additive manufacturing molten pool acoustic emission in-situ detection module, and belongs to the field of metal additive manufacturing. In the module, a cavity and a top opening communicated with the cavity are formed in a base body, a top plate covers the opening and is detachably fixed to the base body, and a sound insulation ring is located at the joint of the top plate and the base body; the sensor cabin is arranged in the cavity and is not in contact with the base body; the waveguide rod is arranged at the upper part in the sensor cabin; the upper end of the waveguide rod extends out of the top of the sensor cabin and is fixed with the lower side part of the top plate; the sensor is arranged in the sensor cabin and is positioned below the waveguide rod; the jackscrew penetrates through the nut from the lower portion of the sensor cabin in a threaded fit mode, and the top of the jackscrew abuts against the lower surface of the sensor, so that the upper surface of the sensor is tightly attached to the lower surface of the waveguide rod, and the waveguide rod abuts against the upper end wall body in the sensor cabin. According to the invention, the purposes of accurate measurement data, simple and convenient installation, easy integration, small occupied space and suitability for different 3D printer equipment and printing working conditions are achieved.

Description

Technical Field

[0001] This invention belongs to the field of metal additive manufacturing technology, and specifically relates to an in-situ detection module for acoustic emission of molten pool in metal additive manufacturing. Background Technology

[0002] Metal additive manufacturing, also known as metal 3D printing, typically uses high-energy heat sources (such as laser beams or electron beams) to selectively melt and fuse basic material units like metal powders / filaments, constructing three-dimensional entities with specific functions. Generally, metal additive manufacturing employs a layer-by-layer deposition method. Compared to traditional mechanical manufacturing methods, metal additive manufacturing offers unique advantages, including personalization, flexibility, high material utilization, and on-site, demand-based production. Currently, metal additive manufacturing is finding increasingly widespread applications in aerospace, defense, biomedicine, transportation, and new energy fields. However, metal additive manufacturing technology still faces technical bottlenecks in areas such as defect suppression and microstructure control in printed parts. This is mainly because the physical processes and mechanisms of the interaction between the heat source and the metal require further understanding. To overcome these technical bottlenecks and improve printing quality and efficiency, more underlying data is needed. Therefore, in-situ detection is crucial for technological breakthroughs in metal additive manufacturing.

[0003] Based on the information transmission channel, in-situ detection technologies can be categorized into optical, electrical, and acoustic methods. Acoustic emission in-situ detection is a method that uses acoustic sensors to capture the sound waves emitted during component printing. Numerous studies have shown that many dynamic structures and behaviors in metal additive manufacturing processes, such as molten pools, keyholes, plumes, and spatter, are accompanied by characteristic acoustic emission phenomena. Therefore, acoustic emission detection is one of the suitable in-situ detection methods for metal additive manufacturing. Acoustic emission detection has many advantages, such as covering both the surface and interior of the metal, sampling rates up to the megahertz level, rich information, and easy integration of the detection device into 3D printers. Based on the medium through which the sound waves are transmitted, acoustic emission detection can be divided into air-guided wave detection and contact wave detection. In comparison, the latter has lower energy attenuation, a higher signal-to-noise ratio, and a wider detection frequency band, making it more suitable for in-situ detection of molten pools and keyholes contained within solid metals.

[0004] The molten pool in metal 3D printing is small, moves rapidly, and its height changes rapidly, generating weak and complex acoustic signals. Furthermore, various mechanical and electromagnetic components of the 3D printer produce noise interference during operation. To ensure that the contact acoustic sensor can acquire a high signal-to-noise ratio and low distortion acoustic signal, it should be positioned close enough to the molten pool while ensuring the safety of the detection equipment. Simultaneously, the sound wave propagation path should be as simple as possible, with minimal heterogeneous medium interfaces to reduce sound dispersion. Noise isolation is also a necessary consideration. Under these requirements, the relative position of the sensor and the forming substrate, the connection method, and the fastening method all require careful design.

[0005] Current in-situ acoustic testing solutions for metal 3D printing have the following technical problems: 1. Excessively Large Structural Size. In academic research and production R&D scenarios, small-scale printing experiments are often required, such as printing critical structures on substrates smaller than 10 cm to reduce material and time costs. Under these conditions, the space available for installing sensors around the small substrate is limited, and existing solutions do not offer specific solutions for sensors in such confined spaces.

[0006] 2. The waveguide structure is cumbersome. Due to the extremely high local temperatures during metal moltenness, a common solution to prevent the sensor's operating temperature from exceeding its tolerance limit is to use a slender metal rod as a waveguide, with one end connected to the sensor and the other fixed to the underside of the molded substrate. However, the introduction of the waveguide rod lengthens the sound wave propagation path, increases the number of interfaces, and leads to more dissipation during sound wave propagation. In existing solutions, the waveguide rod length is usually redundant. While this allows the sensor to be mounted in a more convenient location, it comes at the cost of effective signal loss, increasing the difficulty of capturing transient and weak signals.

[0007] 3. Lack of modularity. In existing solutions, integrating contact acoustic sensors into metal 3D printers typically requires secondary processing or modification of some printer modules, including drilling and tapping, to install the sensor and lead out signal lines. This secondary processing or modification increases the installation cost of the acoustic sensor and creates an irreversible, highly coupled relationship between it and the 3D printer, resulting in poor adaptability.

[0008] 4. Lack of electromagnetic shielding and noise isolation. When a metal 3D printer is working, the surrounding mechanical moving parts and electronic equipment generate noise and electromagnetic interference, and existing solutions do not take specific measures to isolate these interferences. Summary of the Invention

[0009] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one objective of the present invention is to provide an in-situ detection module for acoustic emission of molten pool in metal additive manufacturing, which provides accurate measurement data, is easy to install and integrate, occupies little space, and is applicable to different 3D printer equipment and printing conditions.

[0010] The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to an embodiment of the present invention includes: A substrate having a cavity and a top opening communicating with the cavity; A top plate, which covers the top opening and is detachably fixed to the base; A sound insulation ring is disposed at the connection between the substrate and the top plate; A sensor compartment is disposed in the cavity and does not contact the substrate; a nut is fixed to the bottom of the sensor compartment. A waveguide rod is disposed in the upper part of the sensor compartment, and the upper end of the waveguide rod extends out of the top of the sensor compartment and is fixed to the lower side of the top plate; The sensor is housed within the sensor compartment and located below the waveguide rod. A set screw, threaded through the nut from below the sensor compartment, with its top pressing against the lower surface of the sensor, so that the upper surface of the sensor is in close contact with the lower surface of the waveguide rod, and the waveguide rod is abutted against the upper wall inside the sensor compartment.

[0011] The assembly sequence of the in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to this invention is as follows: ① Place the waveguide rod in the sensor compartment, with the upper end of the waveguide rod passing through the top of the sensor compartment, and install the upper end of the waveguide rod on the lower side of the top plate. ② Secure the nut at the bottom of the sensor compartment. ③ Apply coupling agent to the working surface of the sensor, then place it into the sensor compartment, making it fit against the bottom surface of the waveguide rod. ④ Install the set screws to fix the sensor compartment and its internal components relatively. ⑤ Connect the cable to the sensor, use an insulating film to protect the exposed metal connectors, and then wrap the sensor compartment with aluminum foil. ⑥ Place a sound insulation ring on the top of the substrate, then place the top plate for fixation, and lead out the sensor cable.

[0012] The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to this invention has the following technical effects: First, it is easy to install and integrate, specifically through its well-designed modular packaging. The base and top plate enclose all components, presenting them as a single module, effectively protecting the sensor, shielding noise, and simplifying the integration process with 3D printers. It can be quickly installed onto existing metal 3D printers. Second, it is easy to load and unload. The core component, the sensor compartment, is designed to secure the sensor and waveguide rod with minimal space and fasteners, making loading and unloading convenient. Third, it improves the quality of measurement data. By using sound-absorbing rings to isolate external noise waves and using the top cover and base for electromagnetic shielding, noise interference is significantly reduced. The tight connection between the top plate, waveguide rod, and sensor optimizes the sound wave propagation path, ensuring effective signal acquisition and improving the quality of measurement data, specifically through a high signal-to-noise ratio and minimal noise. Fourth, it is highly adaptable to different 3D printer equipment and printing conditions, facilitating loading, unloading, and transportation. The core components of this invention (waveguide rod, sensor compartment, and sensor) have a compact structure and occupy little space. Therefore, the shape, size, and opening position of the base and top plate can be adjusted according to the inherent structure of the 3D printer, thus adapting to different 3D printers. In particular, by integrating the sensor set with the top plate and base, the size of the top plate can be smaller than that of a conventional 3D printer build platform, making it suitable for small-scale 3D printing experiments.

[0013] In some embodiments, the top plate is smaller than a conventional 3D printer build platform.

[0014] In some embodiments, the sound insulation ring is a plastic washer disposed between the top plate and the substrate.

[0015] In some embodiments, the top is detachably secured to the base using non-metallic fasteners.

[0016] In some embodiments, the non-metallic fastener is a plastic screw.

[0017] In some embodiments, the top plate has a top plate notch at its edge, and the upper part of the base has a base notch, with the top plate notch and the base notch aligned with each other.

[0018] In some embodiments, the upper end of the waveguide rod is threadedly fixed to the lower side of the top plate.

[0019] In some embodiments, the waveguide rod and the sensor cabin are mutually engaged via their respective conical surfaces.

[0020] In some embodiments, the outer surface of the sensor compartment is wrapped with aluminum foil.

[0021] In some embodiments, the circumferential side of the sensor housing is provided with mounting ports for mounting the waveguide rod and the sensor.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is an isometric view of the in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to the present invention; Figure 2 This is a cross-sectional schematic diagram of the in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to the present invention; Figure 3 This is a schematic diagram of the sensor compartment of the in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to the present invention.

[0024] Figure Labels Acoustic emission in-situ detection module 1000; substrate 1; cavity 101; substrate notch 102; top plate 2; top plate notch 201; sound insulation ring 3; plastic washer 301; non-metallic fastener 4; plastic screw 401; sensor compartment 5; mounting port 501; hexagonal hole 502; waveguide rod 6; sensor 7; set screw 8; nut 9. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] The following is combined with Figures 1 to 3 The following describes the in-situ acoustic emission detection module 1000 for molten pool acoustic emission in metal additive manufacturing according to an embodiment of the present invention.

[0027] like Figures 1 to 3 As shown, the in-situ acoustic emission detection module 1000 for molten pool in metal additive manufacturing according to the present invention includes a substrate 1, a top plate 2, a sound insulation ring 3, a non-metallic fastener 4, a sensor compartment 5, a waveguide rod 6, a sensor 7, a set screw 8, and a nut 9.

[0028] The base 1 is connected to the forming cylinder lifting platform of the 3D printer and is used to support the entire metal additive manufacturing molten pool acoustic emission in-situ detection module 1000. The base 1 has a cavity 101 and a top opening communicating with the cavity 101. The cavity 101 is used to accommodate components such as the sensor compartment 5, waveguide rod 6, and sensor 7. In this way, the base 1 can protect the sensor 7 and provide a certain degree of electromagnetic shielding for the sensor 7. The top opening design is mainly to facilitate the installation of related functional components, such as facilitating the placement of the sensor compartment 5 in the cavity 101 of the base 1.

[0029] The top plate 2 covers the top opening and is detachably fixed to the base 1. The top plate 2 can be made of the same metal as the printed part. In this way, the top plate 2 and the base 1 enclose the sensor compartment 5, sensor 7, and waveguide rod 6, achieving modular encapsulation and appearing as a single integrated module. This design effectively protects the sensor 7, shields noise, and simplifies the integration process with the 3D printer. Simultaneously, because the top plate 2 is made of the same metal as the printed part, during the printing process, the top plate 2 acts as a platform supporting the printed part, with the bottom of the printed part directly fused to the upper surface of the top plate 2. The top plate 2 also directly transmits sound waves. After printing, the top plate 2 needs to be removed, the printed part separated using wire cutting, and the upper surface of the top plate 2 restored to a flat surface through grinding or milling.

[0030] The sound insulation ring 3 is set at the connection between the base 1 and the top plate 2; in this way, the sound insulation ring 3 plays a role in sound insulation. When external noise is transmitted from the base 1 to the sensor 7, it will be blocked by the sound insulation ring 3 and a large loss will occur at the interface, which is beneficial to the accuracy of the measurement data of the sensor 7.

[0031] The sensor compartment 5 is housed within the cavity 101 and does not contact the substrate 1. A nut 9 is fixed to the bottom of the sensor compartment 5. The sensor compartment 5 can be made of plastic and is used to mount the sensor 7 and the waveguide rod 6. Specifically, the bottom of the sensor compartment 5 has a hexagonal hole 502 for securing the nut 9. The nut 9 is fixed in the hexagonal hole 502, and the nut 9, in conjunction with the set screw 8, secures the waveguide rod 6 and the sensor 7.

[0032] Waveguide rod 6 is located in the upper part of the sensor compartment 5. The upper end of waveguide rod 6 extends out of the top of the sensor compartment 5 and is fixed to the lower side of the top plate 2; waveguide rod 6 acts as an intermediate medium between the top plate 2 and the sensor 7. During the printing process, especially in the initial stage, metal melts above the top plate 2, resulting in a high temperature, and the sensor 7 cannot directly contact the top plate 2. Waveguide rod 6 serves to dissipate heat and focus the acoustic signal.

[0033] Sensor 7 is located inside sensor compartment 5 and below waveguide rod 6; sensor 7 is used to capture dynamic stress waves during the printing process in real time and convert them into analyzable electrical signals. In other words, top plate 2 converges sound waves through waveguide rod 6 and transmits them to sensor 7, thereby enabling sensor 7 to capture dynamic stress waves during the printing process in real time and convert them into analyzable electrical signals.

[0034] The set screw 8 passes through the nut 9 from below the sensor compartment 5. The top of the set screw 8 presses against the lower surface of the sensor 7, so that the upper surface of the sensor 7 is in close contact with the lower surface of the waveguide rod 6, and the waveguide rod 6 is stuck against the upper wall inside the sensor compartment 5.

[0035] The assembly sequence of the metal additive manufacturing molten pool acoustic emission in-situ detection module 1000 in this embodiment of the invention is as follows: ① Place the waveguide rod 6 in the sensor compartment 5, so that the upper end of the waveguide rod 6 passes through the top of the sensor compartment 5, and install the upper end of the waveguide rod 6 on the lower side of the top plate 2. ② Secure the nut 9 at the bottom of the sensor compartment 5. ③ Apply coupling agent to the working surface of the sensor 7, and then place it into the sensor compartment 5, making it fit against the bottom surface of the waveguide rod 6. ④ Install the set screw 8 to fix the sensor compartment 5 and its internal components relatively. ⑤ Connect the cable to the sensor 7, use an insulating film to protect the exposed metal connector, and then wrap the sensor compartment 5 with aluminum foil. ⑥ Place the sound insulation ring 3 on the top of the base 1, then place the top plate 2 for fixation, and lead out the cable of the sensor 7.

[0036] The in-situ acoustic emission detection module 1000 for molten metal additive manufacturing in this invention has the following technical effects: First, it is easy to install and integrate, specifically through its well-designed modular packaging. The base 1 and top plate 2 enclose all components, presenting them as a single module, effectively protecting the sensor 7, shielding noise, and simplifying the integration process with 3D printers. It can be quickly installed onto existing metal 3D printers. Second, it is easy to install and remove. By designing the core component sensor compartment 5, the sensor 7 and waveguide rod 6 are fixed in a smaller space with fewer fasteners, making installation and removal convenient. Third, it improves the quality of measurement data. By using sound insulation rings 3 to isolate external noise waves and using the top cover and base 1 for electromagnetic shielding, noise interference can be significantly reduced. The tight connection between the top plate 2, waveguide rod 6, and sensor 7 fully optimizes the sound wave propagation path, thereby ensuring effective signal acquisition and improving the quality of measurement data, specifically manifested in a high signal-to-noise ratio and low noise. Fourth, it is highly adaptable to different working conditions and easy to carry. The core components of this invention (waveguide rod 6, sensor compartment 5, sensor 7) have a compact structure and occupy little space. Therefore, the shape, size, and opening position of the base 1 and top plate 2 can be adjusted according to the inherent structure of the 3D printer, thus adapting to different 3D printers. In particular, by integrating the sensor compartment 5 with the top plate 2 and the base 1, the size of the top plate 2 can be smaller than that of a conventional 3D printer build platform, making it suitable for small-scale 3D printing experiments.

[0037] In some embodiments, the top plate 2 is smaller than the conventional 3D printer build platform. In academic research and production R&D scenarios, small-scale printing trials are sometimes required to reduce material and time costs. Therefore, the dimensions of the base 1 and the top plate 2 can be adjusted according to the inherent structure of the 3D printer to accommodate 3D printers of different sizes.

[0038] In some embodiments, the sound insulation ring 3 is a plastic washer 301, which is disposed between the top plate 2 and the base 1. Therefore, external noise, during its propagation to the sensor 7, is blocked by the plastic washer 301, resulting in significant loss at the interface. Specifically, the plastic washer 301 has a positioning portion that abuts against the upper inner wall surface of the base 1. The positioning portion facilitates the installation of the plastic washer 301.

[0039] Specifically, according to the sound intensity transmission formula Where T represents the sound intensity transmission coefficient. This represents the acoustic impedance of the first medium. This represents the acoustic impedance of the second medium, when the acoustic impedance of the media on both sides of the interface... and When the phase difference is large, the transmission coefficient near Sound waves are difficult to transmit through. The acoustic impedance of plastic differs significantly from that of metal, making it more difficult for external noise to be transmitted from the substrate 1 to the top plate 2 and sensor 7. Alternatively, the material of the plastic gasket 301 can be replaced with other materials that have a significantly different acoustic impedance from metal and can withstand certain high temperatures, such as specific rubbers or microcrystalline structures.

[0040] In some embodiments, the top plate 2 and the base 1 are detachably fixed using non-metallic fasteners 4. This arrangement enhances the ease of assembly and disassembly of the device.

[0041] In some embodiments, the non-metallic fastener 4 is a plastic screw 401. Specifically, the top plate 2 has two countersunk holes for installing the plastic screw 401, ensuring that the installed plastic screw 401 does not interfere with the position of other components of the 3D printer. The plastic screw 401 is used to fix the top plate 2 to the base 1 and, together with the sound insulation ring 3, provides sound insulation. Alternatively, the material of the plastic screw 401 can be replaced with other non-metallic materials that have a significantly different acoustic impedance from metal.

[0042] In some embodiments, the top plate 2 has a top plate notch 201 at its edge, and the base 1 has a base notch 102 at its upper part, with the top plate notch 201 and the base notch 102 aligned with each other. In practice, the position and size of the top plate notch 201 and the base notch 102 need to be designed according to the objective conditions of the 3D printer. Setting the top plate notch 201 and the base notch 102 can ensure that the cable can be led out without positional interference. After the module is installed, the top plate notch 201 and the base notch 102 are sealed with sealing material to prevent metal powder from falling into the cavity 101 through the top plate notch 201 and the base notch 102.

[0043] In some embodiments, the upper end of the waveguide rod 6 is threaded to the lower side of the top plate 2. This arrangement makes full use of the limited space while enhancing the ease of assembly and disassembly of the device.

[0044] In some embodiments, the waveguide rod 6 and the sensor compartment 5 are engaged with each other via their respective conical surfaces. The conical shape saves length and reduces energy loss while ensuring good contact and heat dissipation.

[0045] In some embodiments, the outer surface of the sensor compartment 5 is wrapped with aluminum foil. This arrangement provides good electromagnetic shielding and increases detection accuracy.

[0046] In some embodiments, the circumferential side of the sensor housing 5 is provided with mounting ports 501 for mounting the waveguide rod 6 and the sensor 7. The waveguide rod 6 and the sensor 7 can be inserted into and fixed in the sensor housing 5 through the mounting ports 501 on the circumferential side. This structure uses less space and fewer fasteners to fix the sensor 7 and the waveguide rod 6, making it easy to install and remove.

[0047] In some embodiments, the number of sensor modules consisting of sensor compartment 5, waveguide rod 6, and sensor 7 can be one or more. Because the structure of this invention is sufficiently compact, multiple sensor 7 modules can be installed as needed, requiring only the same number of threaded holes as sensor compartment 5 to be pre-drilled on the top plate 2. This further improves the quality of the measurement data.

[0048] In summary, the in-situ acoustic emission detection module 1000 for molten metal additive manufacturing of this invention can solve the problem of integrating the acoustic emission sensor 7 into the metal additive manufacturing substrate and forming an independent module within a confined space, while also ensuring isolation from external noise and electromagnetic interference. Specifically: 1. Make full use of limited space. Threads are designed directly on the waveguide rod 6, and the sensor 7 and the waveguide rod 6 are firmly connected by the sensor compartment 5 and a set screw 8, which simplifies the fasteners, avoids additional space occupation, and enhances the convenience of device assembly and disassembly.

[0049] 2. Optimize the structural design of waveguide rod 6. The diameter of waveguide rod 6 is the same as that of acoustic emission sensor 7, and its length after installation is approximately 1 cm. It is roughly conical in shape with right angles. This design saves length and reduces energy loss while ensuring good contact and heat dissipation.

[0050] 3. Shielding against noise and electromagnetic interference. The sensor 7, waveguide rod 6, and forming top plate 2 are tightly connected. The forming top plate 2 is connected to other components via plastic washers 301 and plastic screws 401, such as... Figure 2 As shown, external noise, when propagating to sensor 7, is blocked by the plastic gasket 301, resulting in significant loss at the interface. Meanwhile, the outer surface of sensor housing 5 can be wrapped with aluminum foil, and the combination of the metal top plate 2 and the base 1 provides excellent electromagnetic shielding.

[0051] 4. Modular packaging. Each component is fully packaged, presenting itself as a whole. It can replace the original molding base plate of the 3D printer and be installed directly without changing other structures of the 3D printer.

[0052] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A metal additive manufacturing molten pool acoustic emission in-situ detection module, characterized in that, include: A substrate having a cavity and a top opening communicating with the cavity; A top plate, which covers the top opening and is detachably fixed to the base; A sound insulation ring is disposed at the connection between the substrate and the top plate; A sensor compartment is disposed in the cavity and does not contact the substrate; a nut is fixed to the bottom of the sensor compartment. A waveguide rod is disposed in the upper part of the sensor compartment, and the upper end of the waveguide rod extends out of the top of the sensor compartment and is fixed to the lower side of the top plate; The sensor is housed within the sensor compartment and located below the waveguide rod. A set screw, threaded through the nut from below the sensor compartment, with its top pressing against the lower surface of the sensor, so that the upper surface of the sensor is in close contact with the lower surface of the waveguide rod, and the waveguide rod is abutted against the upper wall inside the sensor compartment.

2. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 1, characterized in that, The top plate is smaller than the build platform of a conventional 3D printer.

3. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 1, characterized in that, The sound insulation ring is a plastic washer, which is disposed between the top plate and the substrate.

4. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 3, characterized in that, The top is detachably fixed to the base using non-metallic fasteners.

5. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 4, characterized in that, The non-metallic fastener is a plastic screw.

6. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 1, characterized in that, The top plate has a notch at its edge, and the base has a notch at its upper part. The top plate notch and the base notch are aligned with each other.

7. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 1, characterized in that, The upper end of the waveguide rod is fixed to the lower side of the top plate by a thread.

8. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 1, characterized in that, The waveguide rod and the sensor compartment are mutually engaged by their respective conical surfaces.

9. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 1, characterized in that, The outer surface of the sensor compartment is wrapped with aluminum foil.

10. The in-situ acoustic emission detection module for molten pool in metal additive manufacturing according to claim 1, characterized in that, The sensor housing has mounting ports on its circumferential side for mounting the waveguide rod and the sensor.

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