Active protection monitoring device and method for wall damage caused by laser drilling

Abstract

The invention discloses a laser drilling wall damage active protection monitoring device and method, the device comprises a laser, an acoustic emission sensor, a data collector and a controller, the laser is used for emitting a laser beam, and laser drilling is carried out on a machining position of a to-be-machined material; the acoustic emission sensor is installed close to the machining position of a to-be-machined material and used for sensing an acoustic emission signal in the material in the hole forming process of the machined material and conducting acoustic-electric conversion. The data collector is connected with the acoustic emission sensor and is used for collecting the acoustic emission signal to obtain a detection signal; the controller is used for analyzing the detection signals collected by the data collector, monitoring the machining state of laser drilling and judging whether the amplitude of the detection signals is lower than a set threshold value or not, and if yes, an instruction is sent to the laser device, and the laser is turned off. The processing material is directly monitored and is not influenced by stray light, processing light and environmental noise.

Description

Technical Field

[0001] The invention belongs to the technical field of laser processing, and in particular relates to a device and method for actively protecting and monitoring wall damage caused by laser hole making. Background Art

[0002] Laser drilling has the characteristics of high material removal rate, high processing accuracy, and non-contact processing. It is widely used in the processing of precision micro-holes in key components in the fields of aviation and aerospace. In the process of laser drilling, the center area of ​​the hole is often penetrated first. After the breakdown, it is necessary to continue processing and trim the edge of the hole to meet the requirements of the hole shape and accuracy. For parts with inner cavities such as turbine blades, when the holes are repaired after the breakdown, the laser beam will pass through the inner cavity and shine on the opposite wall surface, causing damage to the wall surface, which is called wall damage in the industry. Wall damage will cause the material to be destroyed first in the working state, resulting in a decrease in the comprehensive performance of cavity parts. Therefore, reducing or even completely eliminating wall damage is of great significance for the use of laser to process micro-holes in cavity parts.

[0003] The mainstream wall damage protection methods at home and abroad are mostly passive protection, that is, filling the inner cavity with protective materials, flushing in fluids to reduce laser energy, etc. Filling protective materials requires filling protective materials before laser hole making, waiting for the protective materials to solidify, and removing protective materials after laser hole making. The process is cumbersome, and the laser can still penetrate the protective materials to cause wall damage, and the protection reliability is insufficient. Although the method of flushing in fluids can reduce laser energy, long-term processing will still cause wall damage, and there is also the problem of low reliability.

[0004] Based on the problems of passive protection methods, the industry began to explore active protection methods. CN116532825A, a Chinese patent for "a combined protection method for monitoring and regulating the laser hole making process", uses machine learning to analyze a large number of learning models by monitoring the analysis of light signals and hole depth information during laser processing, and predicts the hole breakdown time. CN118243702A, a Chinese patent for "a method and device for detecting wall damage caused by laser hole making", also uses information from reflected light to monitor the wall damage in situ. CN117929355A, a Chinese patent for "a method, device, equipment and storage medium for monitoring wall protection caused by laser hole making", proposes to fill the inner cavity with a mixture of aluminum oxide and phosphor as a protective material. The phosphor can convert invisible infrared light into visible light. By monitoring the laser-induced breakdown spectrum generated during the laser hole making process, it is monitored whether the laser acts on the protective material, thereby judging whether the hole is broken.

[0005] Existing active protection monitoring methods for wall damage mainly focus on monitoring reflected light signals and plasma spectrum signals during laser hole making. This method is easily interfered by environmental stray light and processing light, resulting in reduced reliability. Summary of the invention

[0006] The main purpose of the present invention is to provide a state monitoring solution for the processed material itself, which is an active protection solution for wall damage during laser hole making, so as to solve the problems of weak protection ability and insufficient reliability of existing passive protection methods and susceptibility to interference of existing active protection methods.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: a laser hole making active protection monitoring device for wall damage, comprising: A laser, used for emitting a laser beam to perform laser drilling on the processing position of the material to be processed; The acoustic emission sensor is installed near the processing position of the material to be processed, and is used to sense the acoustic emission signal inside the material and perform acoustic-to-electric conversion during the hole-making process of the material; A data collector, connected to the acoustic emission sensor, for collecting the acoustic emission signal to obtain a detection signal; The controller is connected to the data collector and the laser, and is used to analyze the detection signal collected by the data collector, monitor the processing status of the laser hole making, and determine whether the amplitude of the detection signal is lower than a set threshold. If so, a command is issued to the laser to turn off the laser.

[0008] In a preferred embodiment, a coupling agent is applied to the detection surface of the acoustic emission sensor, and / or the monitoring frequency range of the acoustic emission sensor is 20kHz~500kHz, and / or the acoustic emission sensor is a resonant sensor, a high temperature sensor or a differential sensor, and / or the distance between the installation position of the acoustic emission sensor and the processing position is 3mm~20mm, and / or the diameter of the acoustic emission sensor is 5mm~30mm and the height is 5mm~60mm, and / or the detection surface of the acoustic emission sensor is made of ceramic or stainless steel, and / or the detection surface of the acoustic emission sensor is a plane or a curved surface, and / or the acoustic emission sensor is directly placed on the material to be processed or fixed on the material to be processed.

[0009] In a preferred embodiment, the coupling agent is silicone grease, vaseline or butter, and / or the center frequency of the acoustic emission sensor is any one frequency or broadband of 40kHz, 50kHz, 70kHz, 150kHz, 200kHz, 250kHz, and 300kHz.

[0010] In a preferred embodiment, the device further comprises a preamplifier, which is connected between the data collector and the acoustic emission sensor and is used for gaining the acoustic emission signal and adjusting the output noise of the acoustic emission signal.

[0011] In a preferred embodiment, the gain of the preamplifier is 20db or 40db or 60db.

[0012] In a preferred embodiment, the device also includes a signal separator and / or an isolator, which is connected between the preamplifier and the data collector, the signal separator is used to separate the DC signal and the AC signal in the acoustic emission signal, and the isolator is used to isolate the DC signal in the acoustic emission signal.

[0013] In a preferred embodiment, the set threshold is 2V~5V.

[0014] On the other hand, the technical solution adopted by the present invention includes: a method for active protection and monitoring of wall damage by laser hole making, comprising: S1, apply coupling agent on the detection surface of the acoustic emission sensor and install it close to the processing position of the material to be processed; S2, set the working parameters of the data collector and laser; S3, the laser emits laser according to its working parameters to perform laser hole making at the processing position of the material to be processed; S4, the acoustic emission sensor senses the acoustic emission signal inside the processed material during the hole making process and performs acoustic-to-electric conversion; S5, the data collector collects the acoustic emission signal according to its working parameters to obtain a detection signal; S6, the controller analyzes the detection signal collected by the data collector, monitors the processing status of the laser hole making, and determines whether the amplitude of the detection signal is lower than the set threshold. If it is lower, it sends a command to the laser to turn off the laser.

[0015] In a preferred embodiment, the coupling agent is silicone grease, and / or the distance between the installation position and the processing position of the acoustic emission sensor is 3 mm to 20 mm, and / or the diameter of the acoustic emission sensor is 5 mm to 30 mm, and the height is 5 mm to 60 mm, and / or the detection surface of the acoustic emission sensor is made of ceramic or stainless steel, and / or the detection surface of the acoustic emission sensor is a plane or a curved surface, and / or the monitoring frequency range of the acoustic emission sensor is 20 kHz to 500 kHz, and the center frequency is any one frequency or broadband of 40 kHz, 50 kHz, 70 kHz, 150 kHz, 200 kHz, 250 kHz, and 300 kHz.

[0016] In a preferred embodiment, the operating parameters of the data collector include a sampling frequency, the sampling frequency range is 50kHz~400kHz, and / or, the operating parameters of the laser include a processing power, the processing power range is 60W~100W, and / or, the set threshold is 2V~5V.

[0017] Compared with the prior art, the beneficial effects of the present invention are at least: 1. The present invention installs an acoustic emission sensor on the processed material to detect the acoustic emission signal emitted by the processed material after being acted upon by the laser beam, collects and analyzes the acoustic emission signal through a data acquisition system, monitors the processing stage status of laser hole making, sets a suitable threshold and issues a command to turn off the laser in a timely manner, thereby achieving the effect of wall protection. This method directly monitors the processed material itself and is not affected by stray light, processing light and environmental noise.

[0018] 2. The present invention adopts an acoustic emission sensor to detect processing materials, which can be applied to the laser processing signal monitoring of all solid materials such as metal materials, brittle materials, composite materials, etc. It has a wide range of applications, and the acoustic emission sensor is small in size, which is convenient for installation in tiny parts and narrow spaces. In addition, the signal acquisition of the acoustic emission sensor is real-time, the sampling time is at the microsecond level, and the response time is at the millisecond level. It does not require a large amount of experimental data for machine learning, so it has the advantages of being simple, convenient, and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of the structure of the active protection monitoring device for wall damage caused by laser hole making provided by the present invention; Figure 2 A schematic diagram of the process flow of the active protection monitoring method for wall damage during laser hole making provided by the present invention; Figure 3 This is a monitoring signal diagram in Example 1 of the present invention; Figure 4 This is a monitoring signal diagram after the threshold is set in Example 1 of the present invention; Figure 5 This is a monitoring signal diagram in Example 2 of the present invention; Figure 6 This is a monitoring signal diagram after the threshold is set in Example 2 of the present invention.

[0021] Reference numerals: 1. Laser, 2. Laser beam, 3. Plasma, 4. Processing position, 5. Material to be processed, 6. Acoustic emission sensor, 7. Preamplifier, 8. Signal separator, 9. Data collector, 10. Controller. DETAILED DESCRIPTION

[0022] The present invention will be more fully understood through the following detailed description, which should be read in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are only exemplary of the present invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be interpreted as limiting, but only as the basis of the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in different ways in virtually any appropriate detailed embodiment.

[0023] like Figure 1 As shown, the present invention discloses an active protection monitoring device for wall damage caused by laser drilling, which is used for active protection monitoring of wall damage caused by laser drilling of a material 5 to be processed, and mainly includes a laser 1, an acoustic emission sensor 6, a data collector 9 and a controller 10.

[0024] Among them, the material to be processed 5 can be all solid materials such as metal materials, brittle materials, composite materials, etc., such as 7075 aluminum alloy or CMC composite materials. Metal materials will undergo elastic deformation under the action of external forces, and will produce plastic deformation when the external load exceeds the yield strength of the material. The changes in its internal stress and plastic deformation are the sources of its acoustic emission signals. When the internal stress of brittle materials changes, cracks are formed and expanded. At this time, the source of the acoustic emission signal is the formation of cracks that force the internal stress concentration to be unloaded. The acoustic emission sources of composite materials include fiber breakage, matrix cracking, fiber extraction, etc. Therefore, the present invention is suitable for laser processing signal monitoring of all solid materials such as metal materials, brittle materials, composite materials, etc., and has a wide range of applications.

[0025] The laser 1 is used to emit a laser beam 2 to perform laser hole making at a processing position 4 of a material to be processed 5, and generate plasma 3. The processing position 4 here is the position where a hole is to be made on the material to be processed 5. During implementation, the laser 1 can be installed above the processing position 4 of the material to be processed 5, but is not limited to it. During implementation, the processing power range of the laser 1 can be 60W~100W.

[0026] The acoustic emission sensor 6 is installed near the processing position 4 of the material to be processed 5, and is used to sense the acoustic emission signal inside the material and perform acoustic-electric conversion during the hole making process of the material to be processed 5. During implementation, the acoustic emission sensor is a resonant sensor, a high temperature sensor, or a differential sensor. A coupling agent is applied on the detection surface of the acoustic emission sensor 6 (i.e., the side that fits the workpiece to be processed), and it is installed near the processing position 4 of the material to be processed 5 to monitor the acoustic emission signal of the processing material itself during the laser hole making process. During implementation, the applied coupling agent can be silicone grease, such as vacuum silicone grease, or vaseline or butter; the detection surface of the acoustic emission sensor 6 can be made of ceramic or stainless steel, and it can be a plane or a curved surface, so that it can be suitable for installation conditions on a plane or a curved surface. The distance between the installation position of the acoustic emission sensor 6 and the processing position 4 is 3mm~20mm, such as preferably 4mm or 6mm. The acoustic emission sensor 6 has an appearance diameter of several tens of millimeters and a small volume, which is convenient for installation of small components and narrow spaces. During implementation, the diameter of the acoustic emission sensor 6 can be 5mm~30mm and the height can be 5mm~60mm. When installing, it only needs to be close to the object to be measured, and can be directly placed on the material to be processed 5, or for special installation conditions, it can be fixed on the material to be processed 5 through other suitable sensor fixing devices (such as clamps, not shown in the figure). As an alternative, there is also an air-coupled acoustic emission sensor that can perform detection without contacting the object to be measured. In addition, the signal acquisition of the acoustic emission sensor 6 is real-time, and the response time is at the millisecond level, and there is no need to conduct a large amount of experimental data for machine learning.

[0027] It should be noted that acoustic emission is a stress wave phenomenon in the material, which is caused by the rapid release of strain energy caused by crack expansion, plastic deformation or phase change. During the laser hole making process, the material to be processed is subjected to the action of the laser beam, which will produce cracks and plastic deformation, that is, generate acoustic emission signals. The acoustic emission sensor 6 is used to detect the acoustic emission signal of the material itself, and the size of the elastic wave inside the material is judged by the amplitude. When the hole is partially penetrated, the area of ​​action between the laser and the material is reduced, the acoustic emission signal of the material itself will decrease, and the amplitude of the monitored acoustic emission signal will also decrease, so that the processing state of the laser hole making can be monitored. And the acoustic emission sensor 6 is different from the sound sensor. The sound sensor detects vibration waves below 10kHz, and the monitoring process is easily disturbed by environmental noise, while the acoustic emission sensor 6 detects stress waves above 20kHz, which belongs to the high-frequency band, and the monitoring process is not disturbed by environmental noise. During implementation, the monitoring frequency range of the acoustic emission sensor 6 can be 20kHz~500kHz, and its center frequency can be any one of 40kHz, 50kHz, 70kHz, 150kHz, 200kHz, 250kHz, 300kHz or broadband, among which broadband is an optional model of the acoustic emission sensor.

[0028] The data collector 9 is connected to the acoustic emission sensor 6 and is used to collect the acoustic emission signal to obtain the detection signal. During implementation, the sampling frequency range can be 50kHz~400kHz.

[0029] The controller 10 is connected to the data collector 9 and the laser 1, and is used to analyze the detection signal collected by the data collector 9, monitor the processing state of the laser hole making, and determine whether the detection signal amplitude is lower than the set threshold. If it is lower, it sends a command to the laser 1 to turn off the laser, thereby achieving the effect of wall protection. During implementation, the set threshold can be 2V~5V, which is used to determine whether the hole is broken down.

[0030] Preferably, a preamplifier 7 may be provided between the data collector 9 and the acoustic emission sensor 6 to increase the acoustic emission signal gain and adjust the output noise of the acoustic emission signal. In practice, the gain of the preamplifier 7 may be 20db, 40db or 60db.

[0031] In addition, a signal separator 8 and / or an isolator (not shown) may be additionally provided between the preamplifier 7 and the data collector 9, wherein the signal separator 8 is used to separate the DC signal and the AC signal in the acoustic emission signal, and the isolator is used to isolate the DC signal in the acoustic emission signal.

[0032] like Figure 2 As shown, the present invention also discloses another technical solution: a method for active protection and monitoring of wall damage caused by laser hole making, which specifically includes the following steps: S1, applying coupling agent to the detection surface of the acoustic emission sensor 6, and installing it close to the processing position 4 of the material to be processed 5.

[0033] S2, setting the working parameters of the data collector 9 and the laser 1.

[0034] S3, the laser 1 emits laser according to its working parameters to perform laser drilling on the processing position 4 of the material 5 to be processed.

[0035] S4, the acoustic emission sensor 6 senses the acoustic emission signal inside the processed material during the hole making process and performs acoustic-to-electric conversion.

[0036] S5, the data collector 9 collects the acoustic emission signal according to its working parameters to obtain a detection signal.

[0037] S6, the controller 10 analyzes the detection signal collected by the data collector 9, monitors the processing status of the laser hole making, and determines whether the amplitude of the detection signal is lower than the set threshold. If it is lower, it sends a command to the laser 1 to turn off the laser.

[0038] The structure, installation position, working parameters, working principle, etc. of each device in each step can refer to the description of the above device, and will not be repeated here.

[0039] Two specific embodiments of the active protection monitoring of wall damage by laser hole making according to the present invention are described below.

[0040] Example 1 Step S1, apply a coupling agent to the detection surface of the acoustic emission sensor 6. The detection surface of the acoustic emission sensor 6 selected in this embodiment is a ceramic surface, and the coupling agent is vacuum silicone grease. The acoustic emission sensor 6 is installed near the processing position 4 of the material to be processed 5. The material to be processed 5 in this embodiment is 7075 aluminum alloy, and the distance between the installation position of the acoustic emission sensor 6 and the hole processing position 4 is 4 mm.

[0041] Step S2, setting the sampling frequency of the data collector 9 to 150kHz, the gain of the preamplifier of the acoustic emission sensor 6 to 60db, the laser processing power to 100W, and the set threshold to 5V.

[0042] Step S3: the laser 1 emits the laser beam 2 at the above processing power to start laser drilling at the processing position 4 of the material 5 to be processed.

[0043] Step S4, the acoustic emission sensor 6 senses the acoustic emission signal inside the processed material during the hole making process and performs acoustic-to-electric conversion; Step S5, the data collector 9 collects the acoustic emission signal according to its working parameters to obtain a detection signal. The detection signal is as follows: Figure 3 shown.

[0044] Step S6: The controller 10 analyzes the detection signal collected by the data collector 9, monitors the processing status of the laser hole making, and determines whether the detection signal amplitude is lower than the set threshold. If it is lower, it sends a command to the laser 1 to turn off the laser. Figure 3 The signal shown in the figure is set at a threshold of 5V. When the amplitude of the monitoring signal is lower than 5V (i.e. the hole has been broken down at this time), the laser beam is turned off and the monitoring signal is processed again. Figure 4 shown. Figure 3 and Figure 4 The horizontal axis is time, and the vertical axis is the amplitude of the acoustic emission signal. The state of laser hole making can be judged by the amplitude.

[0045] Example 2 Step S1, apply coupling agent to the detection surface of the acoustic emission sensor 6. The detection surface of the acoustic emission sensor 6 selected in this embodiment is a ceramic surface, and the coupling agent is vacuum silicone grease. The acoustic emission sensor 6 is installed near the processing position 4 of the material to be processed 5. The material to be processed 5 in this embodiment is a CMC composite material, and the distance between the installation position of the acoustic emission sensor 6 and the hole processing position 4 is 6 mm.

[0046] Step S2, setting the sampling frequency of the data collector 9 to 100kHz, the gain of the preamplifier 7 of the acoustic emission sensor 6 to 60db, setting the laser processing power to 80W, and setting the threshold to 2V.

[0047] Step S3: the laser 1 emits the laser beam 2 at the above processing power to start laser drilling at the processing position 4 of the material 5 to be processed.

[0048] Step S4, the acoustic emission sensor 6 senses the acoustic emission signal inside the processed material during the hole making process and performs acoustic-to-electric conversion; Step S5, the data collector 9 collects the acoustic emission signal according to its working parameters to obtain a detection signal. The detection signal is as follows: Figure 5 shown.

[0049] Step S6: The controller 10 analyzes the detection signal collected by the data collector 9, monitors the processing status of the laser hole making, and determines whether the detection signal amplitude is lower than the set threshold. If it is lower, it sends a command to the laser 1 to turn off the laser. Figure 5 The signal shown in FIG6 is processed again, the threshold is set to 2V, and when the monitoring signal amplitude is lower than 2V (that is, the hole has been broken down at this time), the laser beam 2 is turned off, and the monitoring signal is processed again as shown in FIG6.

[0050] The present invention has the following advantages: 1. The present invention installs an acoustic emission sensor on the processed material to detect the acoustic emission signal emitted by the processed material after being acted upon by the laser beam, and collects and analyzes the acoustic emission signal through a data acquisition system, monitors the processing stage status of the laser hole making, sets a suitable threshold and issues a command to shut down the laser in a timely manner, thereby achieving the effect of wall protection. This method directly monitors the processed material itself and is not affected by stray light, processing light and environmental noise. 2. The present invention uses an acoustic emission sensor to detect the processed material, which can be applied to the laser processing signal monitoring of all solid materials such as metal materials, brittle materials, composite materials, etc. It has a wide range of applications, and the acoustic emission sensor is small in size, which is convenient for installation in small parts and narrow spaces. In addition, the signal acquisition of the acoustic emission sensor is real-time, and the response time is at the millisecond level. It does not require a large amount of experimental data for machine learning, so it has the advantages of being simple, convenient, and easy to operate.

[0051] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all aspects and are not intended to limit the present invention, the scope of the present invention is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0052] The use of headings and sections in this disclosure is not meant to limit the disclosure; each section may apply to any aspect, embodiment, or feature of the disclosure.

Claims

1. An active protection monitoring device for wall damage caused by laser drilling, characterized in that: The device comprises: A laser, used for emitting a laser beam to perform laser drilling on the processing position of the material to be processed; The acoustic emission sensor is installed near the processing position of the material to be processed, and is used to sense the acoustic emission signal inside the material and perform acoustic-to-electric conversion during the hole-making process of the material; A data collector, connected to the acoustic emission sensor, for collecting the acoustic emission signal to obtain a detection signal; The controller is connected to the data collector and the laser, and is used to analyze the detection signal collected by the data collector, monitor the processing status of the laser hole making, and determine whether the amplitude of the detection signal is lower than a set threshold. If so, a command is issued to the laser to turn off the laser.

2. The active protection monitoring device for wall damage during laser hole making according to claim 1 is characterized in that: A coupling agent is applied to the detection surface of the acoustic emission sensor, and / or the acoustic emission sensor is a resonant sensor, a high temperature sensor or a differential sensor, and / or the monitoring frequency range of the acoustic emission sensor is 20kHz~500kHz, and / or the distance between the installation position of the acoustic emission sensor and the processing position is 3mm~20mm, and / or the diameter of the acoustic emission sensor is 5mm~30mm, and the height is 5mm~60mm, and / or the detection surface of the acoustic emission sensor is made of ceramic or stainless steel, and / or the detection surface of the acoustic emission sensor is a plane or a curved surface, and / or the acoustic emission sensor is directly placed on the material to be processed or fixed on the material to be processed.

3. The active protection monitoring device for wall damage during laser hole making according to claim 2 is characterized in that: The coupling agent is silicone grease, vaseline or butter, and / or the center frequency of the acoustic emission sensor is any one frequency or broadband among 40kHz, 50kHz, 70kHz, 150kHz, 200kHz, 250kHz and 300kHz.

4. The active protection monitoring device for wall damage during laser hole making according to claim 1 is characterized in that: The device also includes a preamplifier, which is connected between the data collector and the acoustic emission sensor and is used for acoustic emission signal gain and adjusting output noise of the acoustic emission signal.

5. The active protection monitoring device for wall damage during laser hole making according to claim 4 is characterized in that: The gain of the preamplifier is 20db or 40db or 60db.

6. The active protection monitoring device for wall damage during laser hole making according to claim 4 is characterized in that: The device also includes a signal separator and / or an isolator, which is connected between the preamplifier and the data collector. The signal separator is used to separate the DC signal and the AC signal in the acoustic emission signal, and the isolator is used to isolate the DC signal in the acoustic emission signal.

7. The active protection monitoring device for wall damage during laser hole making according to claim 1 is characterized in that: The set threshold is 2V~5V.

8. A method for active protection and monitoring of wall damage during laser hole making, characterized in that: The method comprises: S1, apply coupling agent on the detection surface of the acoustic emission sensor and install it close to the processing position of the material to be processed; S2, set the working parameters of the data collector and laser; S3, the laser emits laser according to its working parameters to perform laser hole making at the processing position of the material to be processed; S4, the acoustic emission sensor senses the acoustic emission signal inside the processed material during the hole making process and performs acoustic-to-electric conversion; S5, the data collector collects the acoustic emission signal according to its working parameters to obtain a detection signal; S6, the controller analyzes the detection signal collected by the data collector, monitors the processing status of the laser hole making, and determines whether the amplitude of the detection signal is lower than the set threshold. If it is lower, it sends a command to the laser to turn off the laser.

9. The method for active protection and monitoring of wall damage during laser hole making according to claim 8, characterized in that: The coupling agent is silicone grease or vaseline or butter, and / or the distance between the installation position and the processing position of the acoustic emission sensor is 3mm~20mm, and / or the diameter of the acoustic emission sensor is 5mm~30mm, and the height is 5mm~60mm, and / or the detection surface of the acoustic emission sensor is ceramic or stainless steel, and / or the detection surface of the acoustic emission sensor is a plane or a curved surface, and / or the monitoring frequency range of the acoustic emission sensor is 20kHz~500kHz, and the center frequency is any one frequency or broadband of 40kHz, 50kHz, 70kHz, 150kHz, 200kHz, 250kHz, and 300kHz.

10. The method for active protection and monitoring of wall damage during laser hole making according to claim 8, characterized in that: The working parameters of the data collector include sampling frequency, the sampling frequency range is 50kHz~400kHz, and / or, the working parameters of the laser include processing power, the processing power range is 60W~100W, and / or, the set threshold is 2V~5V.

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