CN115343360A - Laser ultrasonic layered self-adaptive mode scanning method and system - Google Patents

Abstract

The invention discloses a laser ultrasonic layered self-adaptive mode scanning method and a system, wherein a scanning area is set according to a metal additive part model; scanning the scanned area in an M1 mode to obtain a laser ultrasonic signal; judging whether the laser ultrasonic signal has defect information or not through time domain analysis; if no defect information exists in the laser ultrasonic signal, scanning in an M1 mode is carried out until a defect is encountered or a set scanning area edge is reached; if the laser ultrasonic signals contain defect information, scanning in an M2 mode to obtain all ultrasonic signals in the region where the defect is located; and obtaining the position of the defect and the diameter of the defect for all ultrasonic signals in the area where the defect is located. The invention can realize the real-time detection of defects in the additive manufacturing process, intervene the manufacturing process according to the real-time detection result, and interrupt the current manufacturing process and repair small defects when the defects are detected; if the detected defect can not be repaired, the manufacturing process can be stopped, and waste is avoided.

Description

A laser ultrasonic layered adaptive mode scanning method and system

technical field

The invention belongs to the technical field of additive manufacturing, and in particular relates to a laser ultrasonic layered adaptive mode scanning method and system.

Background technique

Additive manufacturing technology, also known as 3D printing technology, is a technology that uses CAD design data and the method of accumulating materials layer by layer to manufacture solid parts. Compared with the traditional processing mode of cutting raw materials, it is a "bottom-up "The manufacturing method of material accumulation realizes the manufacture of parts from scratch. Additive manufacturing technology has developed rapidly in recent years. Its advantage lies in the rapid and free manufacturing of three-dimensional structures, which has made it possible to manufacture complex structural parts that were restricted by traditional manufacturing methods in the past. It is widely used in aerospace, medical health and other fields.

However, the quality control of metal additive parts has always been the current research focus. Because of the characteristics of additive manufacturing, high-energy beams are used for manufacturing, and the energy consumption in the manufacturing process is huge, and the manufacturing time is long and the cost is high. If the parts have internal defects and cannot be used, it will cause huge economic losses and waste of time. Considering its "bottom-up" manufacturing feature, quality inspection can be carried out during the manufacturing process. Laser ultrasound is a non-contact, non-damaging, high-temperature-resistant, high-precision detection technology that can be applied to the online real-time detection of the metal additive manufacturing process. If a defect is found, the manufacturing can be suspended for compensation or terminated in advance. , to reduce losses.

In the manufacturing process, the high-energy beam moves fast, but in order to achieve high-precision scanning, the moving scanning points of the laser ultrasonic probe group are dense, and the scanning speed is slow. If the manufacturing time difference between layers is too long, it will affect the manufacturing process. Therefore, it is necessary to study an efficient scanning technology to achieve both efficiency and accuracy. Based on the characteristics of "layer-by-layer increase" of additive manufacturing and the detection requirements of "high efficiency and high precision", combined with the characteristics of laser ultrasonic non-contact, a laser ultrasonic layered self-adaptive mode scan is proposed in the process of metal additive manufacturing method, and design the corresponding hardware system.

Aiming at the laser ultrasonic inspection of the additive manufacturing process, the patent document of application publication number CN106018288A discloses a method for laser ultrasonic online non-destructive inspection of additively manufactured parts, but the method adopts layered and point-by-point scanning with a fixed step length, so that the scanning Too many points, large amount of data, and long detection time reduce the quality and detection efficiency of the actual additive manufacturing parts.

The patent document with application publication number CN202110973449.6 discloses a metal additive synchronous detection system and method based on laser ultrasound and vibrating mirror synergy, but this method does not make path planning for the scanning of the new forming layer, and it is carried out in the entire area of the new forming layer Two-dimensional scanning with a fixed step size has the problems of large amount of data, long detection and calculation time, and low detection efficiency.

Contents of the invention

In order to overcome the problems in the prior art, the present invention provides a laser ultrasonic layered self-adaptive mode scanning method and system in the metal additive manufacturing process. The method can effectively improve the defect detection accuracy and improve the detection efficiency.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

A laser ultrasound layered adaptive mode scanning method, comprising the following steps:

Step 1: Generate the moving path of the manufacturing robot according to the metal additive part model, and set the scanning area according to the moving path of the manufacturing robot;

Step 2: scan the scanning area in M1 mode to obtain laser ultrasonic signals;

Step 3: Through time domain analysis, determine whether there is defect information in the laser ultrasonic signal;

Step 4: If there is no defect information in the laser ultrasonic signal, scan in M1 mode until a defect is encountered or reach the edge of the set scanning area; if the laser ultrasonic signal contains defect information, scan in M2 mode to obtain All ultrasonic signals in the area where the defect is located; wherein, the step size of M2 mode scan is smaller than the step size of M1 mode scan;

Step 5: For all ultrasonic signals in the area where the defect is located in step 4, the defect position and defect diameter are obtained according to the C-scan signal processing method.

Preferably, in step 1, the scanning area is rectangular.

Preferably, the specific process of step 3 is:

Extract the first surface wave propagation time T _R in the laser ultrasonic signal and the first longitudinal wave propagation time T _L in the laser ultrasonic signal, and solve the time domain error ΔT;

判断此时激光超声信号中无缺陷信息，其中，f为干涉仪采样频率；If the time domain error satisfies

Judging that there is no defect information in the laser ultrasonic signal at this time, where f is the sampling frequency of the interferometer;

判断此时激光超声信号中包含缺陷信息。If the time domain error satisfies

It is judged that the laser ultrasonic signal contains defect information at this time.

Preferably, the time domain error ΔT is calculated by the following formula:

ΔT＝|(T _R -t _R )-(T _L -t _L )|

In the formula, t _R is the theoretical propagation time of the surface direct wave, and t _L is the theoretical propagation time of the bottom echo of the longitudinal wave.

Preferably, the theoretical propagation time t _R of the surface direct wave is calculated by the following formula:

In the formula, d is the distance between the excitation point and the receiving point, and v _R is the speed of the surface wave propagating in the material of the metal additive part model.

Preferably, the theoretical propagation time t _L of the bottom echo of the longitudinal wave is calculated by the following formula:

In the formula, d is the distance between the excitation point and the receiving point, h is the overall height of the additive product, and v _L is the speed of longitudinal wave propagation in this material.

Preferably, the specific process of step 4 is as follows:

1) Under the condition that the location of the excitation point remains unchanged, scan point by point on a circle with the excitation point as the center and the step length of the scan in M2 mode as the radius, collect signals, analyze the collected signals in real time, and use The direction where the defect echo appears earliest and the defect echo amplitude is the largest is the direction of the defect;

2) Carry out linear scanning with variable step length in the direction of the defect, collect signals, analyze the collected signals in real time, and take the line connecting the two positions where the defect echo disappears and the defect transmission wave first appears as the diagonal line , the scanning direction of M1 mode is to draw a rectangle along one side, and the rectangle is the area where the defect is located;

3) Carry out type M2 mode scanning in the area where the defect is located, and collect all ultrasonic signals in the area where the defect is located.

Preferably, the scanning step of M1 mode is 0.5mm, 1mm, 1.5mm or 2mm;

The scanning step of M2 mode is 0.1mm, 0.2mm or 0.5mm.

Preferably, after performing step 5, the following steps are performed: judge whether the scanning ranges of the M1 mode and the M2 mode have covered the scanning area, if they are all covered, the scanning ends, and if not covered, then jump to step 2.

The laser ultrasonic layered adaptive mode scanning system adopted by the above method includes a pulsed laser probe, an interferometer probe, a 45° plane mirror and an X-Y optical lens;

Among them, the pulse laser emitted by the pulse laser probe is irradiated on the metal additive part, and the ultrasonic wave is excited on the surface and inside of the metal additive part; the ultrasonic wave on the surface of the metal additive part propagates back through the X-Y optical lens and 45° plane mirror. Interferometer probe.

Compared with the prior art, the present invention has the beneficial effects:

The self-adaptive mode scanning method of the present invention can perform large-step M1 mode scanning in defect-free areas, analyze the collected signals in real time, and perform small-step M2 mode scanning if it is judged that the laser ultrasonic signal contains defect information. Inspection, while taking into account the detection speed and detection accuracy, and there will be no missed detection, which overcomes the problem in the prior art that the detection speed and detection accuracy cannot be considered in the full-area scanning with a fixed step size. In the adaptive mode scanning method proposed in the present invention, the signal is analyzed in real time, and the signal in the non-defective area is analyzed in the simple time domain to save computing resources; the signal in the defective area is processed according to the method of C-scan signal, and sliced according to time , output the slice of the defect echo time, output the defect information, and use the computing resources in the defect area that is focused on. Compared with the existing method, the calculation amount is effectively reduced. The invention can realize real-time detection of defects in the process of additive manufacturing, and intervene in the manufacturing process according to the real-time detection results. When a defect is detected, the current manufacturing process can be interrupted and small defects can be repaired; if the detected defect cannot be repaired, it can be Terminate the manufacturing process and avoid waste from defect generation to manufacturing completion.

Further, the present invention can set different scan step lengths according to the usage of different parts and the tolerance to defects, so as to realize efficient and high-precision detection.

Description of drawings

1 is a schematic diagram of a laser ultrasonic layered adaptive mode scanning system according to an embodiment of the present invention;

Fig. 2 is the realization flowchart of the embodiment of the present invention;

Fig. 3 is a schematic diagram of M1 mode scanning and a schematic diagram of a special point signal in an embodiment of the present invention; wherein, (a) is a schematic diagram of M1 mode scanning, (b) is a schematic diagram of a point A (defect-free area) signal, (c) It is a schematic diagram of the signal at point B (close to the defect area).

Fig. 4 is a schematic diagram of a circular scan in the M2 mode and a schematic diagram of a special point signal in an embodiment of the present invention; wherein, (a) is a schematic diagram of a circular scan in the M2 mode, and (b) is a point A (close to the defect direction ) signal schematic diagram, (c) is the signal schematic diagram of other points (away from the defect position).

Fig. 5 is a schematic diagram of a straight-line scan in the M2 mode and a schematic diagram of a special point signal in an embodiment of the present invention; wherein, (a) is a schematic diagram of a straight-line scan in the M2 mode, and (b) is point A (the excitation and reception are located at the defect Signal diagram on the same side), (c) is a schematic diagram of the signal at point B (the receiving point is located in the defect area), (d) is a schematic diagram of the signal at point C (the excitation and reception are located on the opposite side of the defect).

FIG. 6 is a schematic diagram of a rectangular scan in the M2 mode in an embodiment of the present invention.

In Figure 1, 1 is the substrate, 2 is the connection device, 3 is the pulse laser probe, 4 is the interferometer probe, 5 is the 45° plane mirror, and 6 is the X-Y optical lens.

Detailed ways

The method of the present invention will be further described below in conjunction with the drawings and embodiments.

This embodiment provides a laser ultrasonic layered adaptive mode scanning system for metal additive manufacturing process, as shown in FIG. 1 . Circular, linear and rectangular scanning can be realized through the program. The pulse laser probe is used as the ultrasonic excitation device of the entire scanning system. The pulse laser is emitted by the pulse laser probe 3 and irradiated on the object to be tested, and the ultrasonic wave is excited on the surface and inside of the object; interferometer probe 4, 45° plane mirror 5, X-Y optics The lens 6 constitutes an ultrasonic signal receiving device. The interferometer probe 4 emits continuous laser light to the 45° plane mirror 5, and the optical path generates a 90° deflection, and then irradiates into the X-Y optical lens 6, and then deflects the optical path through the X-Y optical lens 6, and irradiates on the surface of the object. When there is ultrasonic wave propagation on the surface of the workpiece, the surface vibration information is transmitted back to the interferometer probe 4 by the continuous laser along the X-Y optical lens 6 and the 45° plane mirror 5, and the interferometer probe 4 outputs ultrasonic signals to realize the non-contact acquisition of ultrasonic signals. The sampling frequency of instrument probe 4 is f. The interferometer probe 4, 45° plane mirror 5, X-Y optical lens 6, and pulse laser probe 3 are all fixed on the substrate 1 installed on the equipment. When scanning, the substrate 1 of the entire scanning system is fixed on the end of the robot through the connecting device 2 , to realize the scanning during the robot movement. The dotted lines in the figure indicate the optical paths of the pulsed laser and the continuous laser used for detection.

Referring to Fig. 2, a laser ultrasonic layered adaptive mode scanning method for a metal additive manufacturing process of the present invention includes the following steps:

Step 1: Generate the moving path of the manufacturing robot according to the metal additive part model, set the scanning area according to the moving path of the manufacturing robot, and set the scanning area as a rectangle.

Step 2: Set the scanning step of M1 mode. M1 mode is a large-step scan mode, and the general step size can be set to 0.5mm, 1mm, 1.5mm or 2mm;

Step 3: Set the scanning step of M2 mode. The M2 mode is a scan mode with a small step size. The general step length can be set to 0.1mm, 0.2mm or 0.5mm. The step size of the M2 mode needs to be smaller than the step size of the M1 mode.

Step 4: Set the minimum detectable defect size. In the laser ultrasonic layered self-adaptive mode scanning system designed in the present invention, the minimum detectable defect diameter is 0.1 mm, and the minimum detectable defect size can be set according to the application of the additive part.

Step 5: According to the overall height h of the current additive part, the speed v _R of the surface wave propagating in the material of the metal additive part model, the speed v _L of the longitudinal wave propagating in the material, and the distance between the excitation point and the receiving point According to the following formulas, calculate the theoretical propagation time t _R of the current surface direct wave and the theoretical propagation time t _L of the bottom echo of the longitudinal wave.

Step 6: Control the robot to place the scanning system as shown in Figure 1 at the scanning start position, and turn on the scanning system to ensure that the ultrasonic excitation device and the ultrasonic signal receiving device are automatically focused. Referring to (a), (b) and (c) in Fig. 3, start the scanning system, scan in the M1 mode, and acquire the laser ultrasonic signal S.

Step 7: Analyze the collected laser ultrasonic signal S in real time, and judge whether there is a defect in the laser ultrasonic signal S through time-frequency domain and time domain analysis. Specifically include the following steps:

Step 7.1: time-frequency domain analysis of the laser ultrasound signal S. Extract the first peak propagation time T ₁ and the second peak propagation time T ₂ in the laser ultrasonic signal S, and perform short-time Fourier transform on the collected laser ultrasonic signal S to obtain the first peak propagation time T The instantaneous frequency f ₁ of ₁ and the instantaneous frequency f _{2 of the second peak propagation moment T 2 .}

If f ₁ < f ₂ , the ultrasonic wave corresponding to the instantaneous frequency f ₁ at the first peak propagation time T ₁ is a surface wave, T _R = T ₁ ; the ultrasonic wave corresponding to the instantaneous frequency f ₂ at the second peak propagation time T ₂ is longitudinal wave, T _L ＝ T ₂ ;

If f ₁ ≥ f ₂ , the ultrasonic wave corresponding to the instantaneous frequency f ₁ at the first peak propagation time T ₁ is a longitudinal wave, T _L = T ₁ ; the ultrasonic wave corresponding to the instantaneous frequency f ₂ at the second peak propagation time T ₂ is surface wave, T _R = T ₂ ;

Among them, T _R is the propagation time of the first surface wave in the signal S; T _L is the propagation time of the first longitudinal wave in the signal S;

Step 7.2: Time domain analysis of the laser ultrasound signal S. Extract the first surface wave propagation time T _R and the first longitudinal wave propagation time T _L in the laser ultrasonic signal S, and solve the time domain error ΔT.

ΔT＝|(T _R -t _R )-(T _L -t _L )|

判断此时检测点采集到的激光超声信号S中无缺陷信息。其中，f为干涉仪采样频率。If the time domain error satisfies

It is judged that there is no defect information in the laser ultrasonic signal S collected by the detection point at this time. Among them, f is the interferometer sampling frequency.

判断此时检测点采集到的激光超声信号S中包含缺陷信息。If the time domain error satisfies

It is judged that the laser ultrasonic signal S collected by the detection point at this time contains defect information.

Referring to (a) in Figure 3, when there is no defect around point A at the starting position of the scan, the collected signal is shown in (b) in Figure 3, in which there are only surface direct wave signals and longitudinal wave bottom echo signals; when scanning When arriving at point B near the defect, the defect echo and longitudinal wave superimpose in the signal, and it is judged that there is a defect around point B through step 7.2, and M2 mode scanning is required.

Step 8: If there is no defect information in the collected laser ultrasonic signal S, continue to scan in M1 mode until a defect is encountered or reaches the edge of the set scanning area; if the collected signal contains defect information, proceed to Scan in M2 mode to obtain all ultrasonic signals in the area where the defect is located. Specifically include the following steps:

Step 8.1: With the position of the excitation point unchanged, the optical path of the receiving point is changed by the X-Y optical lens, and the receiving point is centered on the excitation point, see (a), (b) and (c) in Figure 4, M2 mode Scanning (circular scanning) scans point by point on a circle whose step length is the radius, analyzes the collected signals in real time, and takes the direction where the defect echo appears earliest and the defect echo amplitude is the largest as the direction of the defect. See (b) and (c) in Figure 4, the signal collected at point A is the point where the defect echo appears the earliest and the defect echo amplitude is the largest among all the signals collected by circular scanning, so the excitation point and A The line connecting the points is the direction of the defect.

Step 8.2: When the position of the excitation point remains unchanged and the direction of the defect is determined, refer to (a), (b), (c) and (d) in Figure 5, change the optical path of the receiving point by the X-Y optical lens, and the receiving point Carry out M2 mode scanning in the direction of the defect. The M2 mode scan is a linear scan with variable step length (the nth receiving point is located at the position of the excitation point n×M2 step length), and the collected signal is analyzed in real time to identify the defect. The line connecting the two positions where the echo disappears and the defect transmission wave appears for the first time is a diagonal line, and the scanning direction of the M1 mode is one of the sides to draw a rectangle, and the rectangle is the area where the defect is located. Referring to (b), (c) and (d) in Figure 5, when the receiving point is located at point A in Figure 5 (a), the defect echo in the signal (b) in Figure 5 is obvious; when the receiving point moves to At position B, because the receiving point is located in the defect, the internal roughness of the defect causes the continuous laser emitted by the interferometer to be unable to focus, so the signal in (c) in Figure 5 has only noise and no ultrasonic information; when the receiving point moves to position C , the defect transmission wave appears in the signal of (d) in Figure 5, so the diagonal line is determined by the line connecting point A and point C, and the rectangle drawn with the scanning direction of M1 mode as a side is shown as the dotted line in (a) of Figure 5 As shown, the rectangle is the area where the defect is located.

When the length of the line connecting point A and point C in (a) in Figure 5 is greater than or equal to the minimum detectable defect size in step 4, it indicates that there are defects that need to be detected in this area, so go to step 8.3 for rectangular scanning ; If the AC connection length is less than the minimum detectable defect size, the defect is acceptable on the surface, so there is no need to continue to scan in M2 mode, skip to step 6 and continue to scan in M1 mode.

Step 8.3: See Figure 6. The dotted line box in Figure 6 is the scanning area, and the solid line box is the metal additive product. Keep the position of the excitation point unchanged, and change the optical path of the receiving point by the X-Y optical lens. The receiving point is in the defect Carry out "S" type M2 mode scan in the area to collect all ultrasonic signals in the area where the defect is located.

Step 9: For the signals collected in step 8.3, according to the C-scan signal processing method, store all the signals in the matrix, slice according to time, and output the slice at the time of the defect echo. The position where the ultrasonic propagation path is disconnected in the slice is is the defect position, the ultrasonic disconnection distance is the defect diameter, and the defect position and defect diameter are defect information.

Step 10: Determine whether the scanning range of the M1 and M2 modes has covered the scanning area, and if it has been completely covered, the scanning ends. If it is not covered, skip to step 6 and continue to scan in M1 mode.

Existing laser ultrasonic scanning methods mostly use full-area scanning with a fixed step size. In order to ensure the detection accuracy, the scanning step size is set very small, resulting in a huge amount of collected data, and the data collection process is long, which affects manufacturing efficiency. and quality; when the detection efficiency is to be ensured, the scanning step length must be set larger, resulting in missed detection of small-sized defects. The detection speed and detection accuracy cannot be achieved in the whole-area scanning with a fixed step length, but the adaptive mode scanning method proposed by the present invention can perform large-step scanning in non-defective areas and small-step scanning in defective areas. Long scan, taking into account the detection speed and detection accuracy at the same time, and there will be no missed detection.

The amount of data collected by the existing laser ultrasonic full-area fixed-step scanning scan is large, and the amount of calculation for signal processing after the acquisition is completed is large. However, in the self-adaptive mode scanning method proposed in the present invention, the signal is analyzed in real time, and the signal in the non-defect area is simply calculated to save computing resources; the signal in the defect area is focused on calculation, and the computing resources are used in the key attention area , compared with existing methods, effectively reducing the amount of computation.

Claims (10)

1. A laser ultrasonic layered self-adaptive mode scanning method is characterized by comprising the following steps:

step 1: generating a manufacturing robot moving path according to the metal additive product model, and setting a scanning area according to the manufacturing robot moving path;

step 2: scanning the scanned area in an M1 mode to obtain a laser ultrasonic signal;

and step 3: judging whether the laser ultrasonic signal has defect information or not through time domain analysis;

and 4, step 4: if no defect information exists in the laser ultrasonic signal, scanning in an M1 mode is carried out until a defect is encountered or a set scanning area edge is reached; if the laser ultrasonic signals contain defect information, scanning in an M2 mode to obtain all ultrasonic signals in the region where the defect is located; wherein the step length of the M2 mode scanning is smaller than that of the M1 mode scanning;

and 5: and (5) obtaining the position and the diameter of the defect of all the ultrasonic signals in the region where the defect is located in the step (4) according to a C-scan signal processing method.

2. The laser ultrasonic layered adaptive mode scanning method according to claim 1, wherein in the step 1, the scanned area is rectangular.

3. The laser ultrasonic layered adaptive mode scanning method according to claim 1, characterized in that the specific process of step 3 is as follows:

extracting the first surface wave propagation time T in the laser ultrasonic signal _R And the propagation time T of the first longitudinal wave in the laser ultrasonic signal _L Solving a time domain error delta T;

if the time domain error is satisfied

Judging non-defective information in the laser ultrasonic signal at the moment, wherein f is the sampling frequency of the interferometer;

if the time domain error is satisfied

And judging that the laser ultrasonic signal contains defect information at the moment.

4. The laser ultrasonic layered adaptive mode scanning method according to claim 3, wherein the time-domain error Δ T is calculated by the following formula:

ΔT＝|(T _R -t _R )-(T _L -t _L )|

in the formula, t _R Is the theoretical propagation time of the surface direct wave, t _L The theoretical propagation time of the bottom echo of the longitudinal wave is shown.

5. The laser ultrasonic layered adaptive mode scanning method according to claim 4, characterized in that the surface direct wave theoretical propagation time t _R Calculated by the following formula:

where d is the distance between the excitation point and the reception point and v _R Is the speed of propagation of the surface wave in the material of the metallic additive product model.

6. The laser ultrasonic layered adaptive mode scanning method according to claim 5, wherein the theoretical propagation time t of the bottom echo of the longitudinal wave is t _L Calculated by the following formula:

wherein d is the distance between the excitation point and the receiving point, h is the overall height of the additive product, and v _L Is the speed at which longitudinal waves propagate in such a material.

7. The laser ultrasonic layered adaptive mode scanning method according to claim 1, characterized in that the specific process of step 4 is as follows:

1) Under the condition that the position of an excitation point is not changed, scanning point by point on a circle which takes the excitation point as the center of a circle and takes the step length of scanning in an M2 mode as the radius, acquiring signals, analyzing the acquired signals in real time, and taking the direction with the earliest defect echo occurrence time and the largest defect echo amplitude as the direction of a defect;

2) Performing linear scanning with variable step length in the direction of the defect, acquiring signals, analyzing the acquired signals in real time, and drawing a rectangle by taking a connecting line of two positions where the defect echo disappears and the defect transmission wave appears for the first time as a diagonal line and the scanning direction of the M1 mode as a side, wherein the rectangle is an area where the defect is located;

3) And scanning the defect in the region in which the defect is positioned in a M2 mode, and acquiring all ultrasonic signals in the region in which the defect is positioned.

8. The laser ultrasonic layered adaptive mode scanning method according to claim 1, characterized in that the scanning step length of the M1 mode is 0.5mm, 1mm, 1.5mm or 2mm;

the scanning step length of the M2 mode is 0.1mm, 0.2mm or 0.5mm.

9. The laser ultrasonic layered adaptive mode scanning method according to claim 1, characterized in that after step 5, the following steps are performed: and (3) judging whether the scanning ranges of the M1 mode and the M2 mode cover the scanning area, if so, finishing the scanning, and if not, skipping to the step 2.

10. A laser ultrasonic layered adaptive mode scanning system used in the method of any one of claims 1-9, which comprises a pulse laser probe (3), an interferometer probe (4), a 45 ° plane mirror (5) and an X-Y optical lens (6);

pulse laser emitted by the pulse laser probe (3) irradiates on the metal additive manufacturing part, and ultrasonic waves are excited on the surface and inside of the metal additive manufacturing part; ultrasonic waves on the surface of the metal additive workpiece are transmitted back to the interferometer probe (4) through the X-Y optical lens (6) and the 45-degree plane mirror (5), and the interferometer probe (4) outputs ultrasonic signals.

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