CN115343360A - Laser ultrasonic layered self-adaptive mode scanning method and system - Google Patents
Laser ultrasonic layered self-adaptive mode scanning method and system Download PDFInfo
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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
Technical Field
The invention belongs to the technical field of additive manufacturing, and particularly relates to a laser ultrasonic layered self-adaptive mode scanning method and system.
Background
The additive manufacturing technology is also called 3D printing technology, is a technology for manufacturing solid parts by adopting a material layer-by-layer accumulation method through CAD design data, is a manufacturing method of 'bottom-up' material accumulation compared with the traditional processing mode for cutting raw materials, and realizes the inexhaustible manufacturing of parts. The additive manufacturing technology is rapidly developed in recent years, and has the advantages that the three-dimensional structure is rapidly and freely manufactured, so that the manufacture of complex structural parts which cannot be realized due to the constraint of the traditional manufacturing mode becomes possible in the past, and the additive manufacturing technology is widely applied to the fields of aerospace, medical health and the like.
However, quality control of metal additive products is always the focus of current research, because of the characteristics of additive manufacturing, high-energy beams are used for manufacturing, energy consumption in the manufacturing process is huge, manufacturing time is long, cost is high, and if the internal defects of the products are found after manufacturing is completed and the products cannot be used, huge economic loss and time waste are caused. Considering the manufacturing characteristics of the device from bottom to top, the quality detection can be carried out in the manufacturing process. The laser ultrasonic is a non-contact, non-destructive, high-temperature-resistant and high-precision detection technology, can be applied to online real-time detection in the metal additive manufacturing process, and can perform suspension manufacturing to perform compensation operation or terminate manufacturing in advance to reduce loss if defects are found.
In the manufacturing process, the high-energy beam has a high moving speed, in order to achieve high-precision scanning, the moving scanning points of the laser ultrasonic probe group are dense, the scanning speed is low, and if the manufacturing time difference between layers is too long, the mechanical property of a workpiece is affected, so that an efficient scanning technology needs to be researched to achieve the effect of taking efficiency and precision into consideration. The invention provides a laser ultrasonic layering self-adaptive mode scanning method in a metal additive manufacturing process according to the characteristic of 'layer-by-layer increase' in additive manufacturing and the detection requirement of 'high efficiency and high precision', and the characteristic of laser ultrasonic non-contact is combined, and a corresponding hardware system is designed.
For laser ultrasonic detection in an additive manufacturing process, patent document with application publication number CN106018288a discloses a method for laser ultrasonic online nondestructive testing of additive manufacturing parts, but the method adopts fixed step length layered point-by-point scanning, so that the number of scanning points is too many, the data size is large, the detection time is long, and the quality and the detection efficiency of actual additive manufacturing parts are reduced.
Patent document with application publication number CN202110973449.6 discloses a metal additive synchronous detection system and method based on laser ultrasound and galvanometer cooperation, but the method does not perform path planning for scanning of a new forming layer, and performs two-dimensional scanning with fixed step length in the whole area of the new forming layer, and has the problems of large data size, long time consumption for detection and calculation, and low detection efficiency.
Disclosure of Invention
In order to overcome the problems in the prior art, the invention provides a laser ultrasonic layered self-adaptive mode scanning method and system in the metal additive manufacturing process, and the method can effectively improve the defect detection precision and improve the detection efficiency.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a laser ultrasonic layered self-adaptive mode scanning method comprises 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 3, 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 4, obtaining the position and the diameter of the defect of all the ultrasonic signals in the area where the defect is located in the step 4 according to a C-scanning signal processing method.
Preferably, in step 1, the scanned area is rectangular.
Preferably, the specific process of step 3 is:
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.
Preferably, the temporal error Δ T is calculated by:
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.
Preferably, 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 the surface wave propagating in the material of the metallic additive product model.
Preferably, the theoretical propagation time t of the bottom echo of the longitudinal wave 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.
Preferably, 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.
Preferably, 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.
Preferably, 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.
The laser ultrasonic layered self-adaptive mode scanning system adopted by the method comprises a pulse laser probe, an interferometer probe, a 45-degree plane mirror and an X-Y optical lens;
the method comprises the following steps that pulse laser emitted by a pulse laser probe irradiates on a metal additive material part, and ultrasonic waves are excited on the surface and the inside of the metal additive material part; ultrasonic waves on the surface of the metal additive workpiece are transmitted back to the interferometer probe through the X-Y optical lens and the 45-degree plane mirror.
Compared with the prior art, the invention has the following beneficial effects:
the self-adaptive mode scanning method can perform large-step M1 mode scanning in a non-defective area, analyze acquired signals in real time, perform small-step M2 mode scanning if the laser ultrasonic signals are judged to contain defect information, simultaneously consider detection speed and detection precision, avoid the condition of missing detection and solve the problem that the detection speed and the detection precision cannot be considered in the whole area scanning with fixed step length in the prior art. In the self-adaptive mode scanning method provided by the invention, the signals are analyzed in real time, and the signals in a non-defective area are simply analyzed in a time domain, so that the computing resources are saved; and for the defect area signal, slicing is performed according to time according to a C-scan signal processing method, slicing at the defect echo moment is output, defect information is output, and computing resources are used in the defect area which is focused on, so that the computing amount is effectively reduced compared with the existing method. 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 from defect generation to manufacturing completion is avoided.
Furthermore, the invention can set different scanning step lengths according to the purposes of different parts and the tolerance to defects so as to realize high-efficiency and high-precision detection.
Drawings
FIG. 1 is a schematic diagram of a laser ultrasound layered adaptive mode scanning system of an embodiment of the present invention;
FIG. 2 is a flow chart of an implementation of an embodiment of the present invention;
FIG. 3 is a schematic diagram of an M1 mode scanning and 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 signals of point A (non-defective region), and (c) is a schematic diagram of signals of point B (near-defective region).
FIG. 4 is a schematic diagram of a circular scan and a special point signal in M2 mode in an embodiment of the present invention; wherein, (a) is a schematic diagram of a circle scanning in an M2 mode, (b) is a schematic diagram of a signal of a point A (close to a defect direction), and (c) is a schematic diagram of a signal of the rest points (far from a defect position).
FIG. 5 is a schematic diagram of a line scan and a special point signal in M2 mode according to an embodiment of the present invention; wherein, (a) is a schematic diagram of linear scanning in an M2 mode, (B) is a schematic diagram of a signal of a point A (excitation and reception are positioned at the same side of a defect), (C) is a schematic diagram of a signal of a point B (reception point is positioned in a defect region), and (d) is a schematic diagram of a signal of a point C (excitation and reception are positioned at different sides of the defect).
Fig. 6 is a schematic diagram of rectangular scanning in M2 mode in an embodiment of the present invention.
In fig. 1, 1 is a substrate, 2 is a connecting device, 3 is a pulse laser probe, 4 is an interferometer probe, 5 is a 45 ° plane mirror, and 6 is an X-Y optical lens.
Detailed Description
The method of the present invention is further described below with reference to the accompanying drawings and examples.
The embodiment provides a laser ultrasonic layered adaptive mode scanning system for a metal additive manufacturing process, as shown in fig. 1. Circular, linear and rectangular scanning can be realized through a program. The pulse laser probe is used as an ultrasonic excitation device of the whole scanning system, pulse laser is emitted by the pulse laser probe 3, irradiates on an object to be detected and excites ultrasonic waves on the surface and inside of the object; an interferometer probe 4, a 45-degree plane mirror 5 and an X-Y optical lens 6 form an ultrasonic signal receiving device, the interferometer probe 4 transmits continuous laser to the 45-degree plane mirror 5, a light path deflects by 90 degrees, the continuous laser irradiates the X-Y optical lens 6 and then irradiates the surface of an object through light path deflection in the X-Y optical lens 6, when ultrasonic waves are transmitted on the surface of a workpiece, surface vibration information is reversely transmitted back to the interferometer probe 4 along the X-Y optical lens 6 and the 45-degree plane mirror 5 by the continuous laser, the interferometer probe 4 outputs ultrasonic signals, non-contact acquisition of the ultrasonic signals is achieved, and the sampling frequency of the interferometer probe 4 is f. The interferometer probe 4, the 45-degree plane mirror 5, the X-Y optical lens 6 and the pulse laser probe 3 are all fixed on a substrate 1 installed on equipment, when scanning is carried out, the substrate 1 of the whole scanning system is fixed at the tail end of a robot through a connecting device 2, and scanning is achieved in the moving process of the robot. The dashed lines in the figure are marked as the optical paths of the pulsed laser light and the continuous laser light for detection.
Referring to fig. 2, the laser ultrasonic layered adaptive mode scanning method for the metal additive manufacturing process of the present invention includes 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, wherein the scanning area is set to be rectangular.
Step 2: and setting the scanning step length of the M1 mode. The M1 mode is a large step length scanning mode, and the general step length can be set to be 0.5mm, 1mm, 1.5mm, 2mm or the like;
and step 3: and setting the scanning step length of the M2 mode. The M2 mode is a small step scanning mode. Typical step sizes may be set at 0.1mm, 0.2mm or 0.5mm. The step size of the M2 mode needs to be smaller than that of the M1 mode.
And 4, step 4: a minimum detectable defect size is set. In the laser ultrasonic layered self-adaptive mode scanning system designed by the invention, the minimum detectable defect diameter is 0.1mm, and the minimum detectable defect size can be set according to the use of the material adding workpiece.
And 5: according to the overall height h of the current additive product, the propagation speed v of the surface wave in the material of the metal additive product model R Velocity v of longitudinal wave propagating in such material L And the distance d between the excitation point and the receiving point and other parameters, and the theoretical propagation time t of the direct wave on the current surface is calculated according to the following formula R Bottom surface echo theory propagation time t of longitudinal wave L 。
Step 6: and controlling the robot to place the scanning system shown in the figure 1 at a scanning initial position, starting the scanning system, and determining the automatic focusing of the ultrasonic excitation device and the ultrasonic signal receiving device. Referring to (a), (b) and (c) in fig. 3, the scanning system is started to perform M1 mode scanning, and the laser ultrasonic signal S is acquired.
And 7: and analyzing the acquired laser ultrasonic signal S in real time, and judging whether the laser ultrasonic signal S has defects or not through time-frequency domain and time domain analysis. The method specifically comprises the following steps:
step 7.1: and (3) analyzing laser ultrasonic signals S time-frequency domain. Extracting a first peak propagation time T occurring in a laser ultrasonic signal S 1 And a second peak propagation time T 2 Carrying out short-time Fourier transform on the acquired laser ultrasonic signal S to obtain a first peak propagation time T 1 Instantaneous frequency f 1 And a second peak propagation time T 2 Instantaneous frequency f 2 。
If f 1 ＜f 2 The first peak propagation time T 1 Instantaneous frequency f 1 The corresponding ultrasonic wave is surface wave, T R ＝T 1 (ii) a Second peak propagation time T 2 Instantaneous frequency f 2 The corresponding ultrasonic wave is a longitudinal wave, T L ＝T 2 ；
If f 1 ≥f 2 The first peak propagation time T 1 Instantaneous frequency f 1 The corresponding ultrasonic wave is a longitudinal wave, T L ＝T 1 (ii) a Second peak propagation time T 2 Instantaneous frequency f 2 The corresponding ultrasonic wave is a surface wave, T R ＝T 2 ；
Wherein, T R Is the first surface wave travel time in signal S; t is L Is the first longitudinal wave propagation time in the signal S;
and 7.2: and (5) analyzing the laser ultrasonic signal S time domain. Extracting a first surface wave propagation time T occurring in a laser ultrasonic signal S R And the first longitudinal wave propagation time and T L And solving the time domain error delta T.
ΔT＝|(T R -t R )-(T L -t L )|
If the time domain error is satisfied
And judging non-defective information in the laser ultrasonic signal S acquired at the detection point. Wherein f is the interferometer sampling frequency.
If the time domain error is satisfied
And judging that the laser ultrasonic signal S acquired at the detection point contains defect information.
Referring to fig. 3 (a), when there is no defect around the scanning start position point a, the acquired signals are as in fig. 3 (b), and only the surface direct wave signal and the longitudinal wave bottom echo signal are in the signals; when the position of the B point near the defect is scanned, the condition that the defect echo and the longitudinal wave are superposed appears in the signal, and the defect is judged to exist around the B point through the step 7.2, and the M2 mode scanning is required.
And 8: if no defect information exists in the acquired laser ultrasonic signal S, continuing to carry out M1 mode scanning until a defect is encountered or a set scanning area edge is reached; and if the acquired signals contain defect information, scanning in an M2 mode to obtain all ultrasonic signals in the region where the defect is located. The method specifically comprises the following steps:
step 8.1: under the condition that the position of the excitation point is not changed, the X-Y optical lens changes the light path of a receiving point, the receiving point performs point-by-point scanning on a circle which takes the excitation point as the center of a circle, see (a), (b) and (c) in figure 4, the step length of M2 mode scanning (circular scanning) is taken as the radius, the acquired signals are analyzed in real time, and the direction with the earliest defect echo occurrence time and the maximum defect echo amplitude is taken as the direction of the defect. Referring to (b) and (c) in fig. 4, the signal acquired at point a is the point with the earliest defect echo occurrence time and the largest defect echo amplitude in all the signals acquired by circular scanning, and therefore, the connecting line between the excitation point and point a is the direction of the defect.
Step 8.2: under the condition that the position of an excitation point is unchanged and the direction of a defect is determined, referring to (a), (b), (c) and (d) in fig. 5, an X-Y optical lens changes the light path of a receiving point, the receiving point performs M2 mode scanning in the defect direction, the M2 mode scanning is linear scanning with variable step length (the nth receiving point is located at the position of the excitation point n multiplied by M2 step length), the acquired signals are analyzed in real time, the connecting line of two positions where a defect echo disappears and a defect transmission wave appears for the first time is used as a diagonal line, the M1 mode scanning direction is used for drawing a rectangle on one of the sides, and the rectangle is an area where the defect is located. Referring to (b), (c) and (d) in fig. 5, when the receiving point is located at the position of the a point in (a) in fig. 5, the defect echo in the signal in (b) in fig. 5 is obvious; when the receiving point moves to the position B, because the receiving point is located in the defect, the internal roughness of the defect is large, so that continuous laser emitted by the interferometer cannot be focused, and therefore, the signal in (c) in FIG. 5 has only noise and no ultrasonic information; when the receiving point moves to the C position, a defect transmission wave appears in the signal in (d) in fig. 5, so that a diagonal line is determined by a connecting line of the point a and the point C, and a rectangle drawn with the M1 mode scanning direction as one side is shown by a dotted line in (a) in fig. 5, and the rectangle is a region where the defect exists.
When the length of the connection line between the point a and the point C in (a) in fig. 5 is greater than or equal to the minimum detectable defect size in step 4, it indicates that there is a defect to be detected in this area, and therefore, the rectangular scanning is performed in step 8.3; if the length of the AC connecting line is smaller than the minimum detectable defect size, the defect on the surface can be received, so that M2 mode scanning does not need to be carried out continuously, and the step 6 is skipped to carry out M1 mode scanning continuously.
Step 8.3: referring to fig. 6, in fig. 6, a dotted line box is a scanning area, a solid line box is a metal additive manufacturing part, the position of an excitation point is kept unchanged, an X-Y optical lens changes the light path of a receiving point, the receiving point performs S-type M2 mode scanning in the area where the defect is located, and all ultrasonic signals in the area where the defect is located are collected.
And step 9: and (4) storing all the signals acquired in the step (8.3) in a matrix according to a C-scan signal processing method, slicing according to time, outputting slices at the moment of defect echo, wherein the position of the ultrasonic propagation path in each slice is a defect position, the distance of the ultrasonic break is a defect diameter, and the defect position and the defect diameter are defect information.
Step 10: and judging whether the scanning ranges of the M1 mode and the M2 mode cover the scanning area, and if the scanning ranges cover the scanning area completely, finishing the scanning. And if not, jumping to step 6 and continuing to carry out M1 mode scanning.
The existing laser ultrasonic scanning method mostly adopts the whole-area scanning with fixed step length, and in order to ensure the detection precision, the scanning step length is set to be very small, so that the acquired data volume is huge, the data acquisition process is long, and the manufacturing efficiency and quality are influenced; when the detection efficiency is ensured, the scanning step length must be set to be larger, so that the small-size defects are missed to be detected. The detection speed and the detection precision can not be obtained in the whole-region scanning of a fixed step length, but the self-adaptive mode scanning method provided by the invention can be used for carrying out large-step-length scanning on a non-defective region and small-step-length scanning on a defective region, and simultaneously has the detection speed and the detection precision and can not cause the condition of missing detection.
The data volume of the existing laser ultrasonic full-area fixed step length scanning acquisition is large, and the calculation amount for signal processing after the acquisition is finished is large. In the self-adaptive mode scanning method provided by the invention, the signals are analyzed in real time, the signals in the non-defective area are simply calculated, and the calculation resources are saved; and performing key calculation on the signals of the defect area, and using the calculation resources in the key attention area, thereby effectively reducing the calculation amount compared with the existing method.
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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