A method and system for compensating for defects in a laser shock peening process

Abstract

The application discloses a laser shock peening process defect compensation method, which comprises the following steps: S1, acquiring sound signal intensity λ of each point of a workpiece to be strengthened during laser shock peening; S2, sequentially comparing each sound signal intensity λ with normal sound signal intensity λ determined by pre-pressing C , and setting a lower limit difference a, if λ C -a exists, it is determined that the point is a defect point, and the lower limit difference a is obtained by averaging a plurality of test values under the same condition; S3, if the defect point exists, laser shock peening compensation is performed on each defect point. The application further discloses a laser shock peening defect compensation system. The application can effectively solve the problems that single parameter laser peening compensation easily causes mechanical deformation of a compensation part of a metal workpiece, and residual stress level of the compensation part is higher than that of the surrounding part and destroys consistency of the whole part.

Description

Technical Field

[0001] This invention belongs to the field of laser shock peening technology, specifically relating to a defect compensation method and system for the laser shock peening process. Background Technology

[0002] Laser shock peening is a novel surface modification technology for metallic materials. It utilizes the high-intensity compressive stress shock wave generated when a high-energy pulsed laser beam irradiates a metal to induce impact plastic deformation in the metal. Figure 3 The diagram illustrates the basic principle of laser shock peening. During laser processing, due to the influence of laser irradiation, the laser beam penetrates the water-constrained layer and is absorbed by the energy-absorbing layer attached to the surface of the metal workpiece. The temperature at the irradiated area reaches an extremely high value in a very short time, causing vaporization. This vaporization forms ionized vapor, and if the laser irradiation energy continues to be absorbed, plasma is formed. When the energy rapidly accumulates to a critical value, it causes an expansion explosion. The detonation wave generated by the plasma from the continuous laser action acts on the surface of the metal target, forming a shock wave directed towards the metal workpiece. When the pressure caused by the shock wave is much greater than the dynamic yield strength that the target material can withstand, the area affected by the shock wave undergoes plastic deformation under ultra-high strain rate. Accompanying this is a rapid increase in dislocation density, the surface material grains are refined, and a high-amplitude residual compressive stress region of a certain depth is formed on the metal surface. Simultaneously, structural changes such as phase transformation and twinning occur, thereby improving the material's fatigue resistance, toughness, fracture resistance, and other mechanical properties. Compared with traditional strengthening methods such as shot peening, burnishing, and surface alloying, laser shock peening has technical advantages such as better strengthening effect, stronger controllability, and wider applicability.

[0003] However, some defects still exist in the laser shock annealing process. For example, during laser shock annealing, certain specific areas, such as the root of blades and gears, may experience issues. Figure 4 As shown, due to the difficulty of forming a uniformly thick absorption layer and / or constraint layer at the corresponding location using existing technologies, the impact strengthening effect is difficult to achieve the set value, resulting in under-strengthening. For example... Figure 5 As shown, for this understrength condition, the current common practice is to use single-parameter impact strengthening to compensate for it. However, due to the cumulative effect of multiple impact strengthenings, the mechanical deformation and residual stress level of this part are higher than the surrounding values, which disrupts the consistency of the overall strengthening level of the part.

[0004] Therefore, there is an urgent need for a defect compensation technology in the laser shock strengthening process to achieve quantitative control of the compensation value of multiple shock strengthenings, so as to achieve the same level as the first shock strengthening effect and ensure the consistency of the overall strengthening effect of the part. Summary of the Invention

[0005] To address the problem in the background art that single-parameter laser strengthening compensation can easily cause mechanical deformation of the compensation area and residual stress levels higher than the surrounding values, thus disrupting the overall consistency of the strengthening level of the part, this invention provides a defect compensation method and compensation system for the laser shock strengthening process.

[0006] The technical solution of this invention to solve the technical problem is as follows:

[0007] This invention discloses a defect compensation method for laser shock peening processes, comprising the following steps:

[0008] S1. Obtain the acoustic signal intensity λ of each point of the workpiece to be strengthened during laser shock strengthening;

[0009] S2. Sequentially compare each of the aforementioned acoustic signal intensities λ with the pre-sampled normal acoustic signal intensity λ. C Compare the values, set a lower limit difference a, and if there exists λ < λ C If –a, then this point is determined to be a defect point. The lower limit difference value a is obtained by taking the average value of multiple sets of tests under the same conditions in advance.

[0010] S3. If the aforementioned defect points exist, laser shock reinforcement compensation shall be performed on each defect point.

[0011] Furthermore, when performing laser shock strengthening compensation on each of the aforementioned defect points, the acoustic signal intensity λ of each defect point on the workpiece during laser shock strengthening compensation is continuously acquired, and whether there are still defect points is monitored through the method described in step S2. Laser shock strengthening compensation is then performed on the remaining defect points, and so on until the compensation is completed.

[0012] Furthermore, in step S3, when performing laser shock strengthening compensation on each of the defect points, the following steps are performed:

[0013] S301. On the workpiece, take the defect point with the minimum sound signal intensity λ as the central defect area and expand outward to form a compensation area. Ensure that each point in the outermost expansion area is a non-defect point. Then, in the same manner, establish compensation areas for other defect points not included in the above compensation area.

[0014] S302. Sequentially measure the ablation depth h1 of each point in each region of the compensation zone corresponding to the absorption layer position, and calculate the average ablation depth h1 of the absorption layer in each region. C ;

[0015] S303. Set the difference range value δ0, and set the average value h1 of the ablation depth of the absorption layer in each extended area of ​​each compensation zone. C The average ablation depth h1 of the absorption layer in the central defect region CThe difference δ is compared with δ0. When |δ|≥δ0, the extended area is determined to be a nearby defect area. The difference range value δ0 is obtained by taking the average value of multiple sets of tests under the same conditions.

[0016] S304. Laser shock reinforcement compensation is performed sequentially on each defect point in each defect area of ​​each compensation zone.

[0017] Furthermore, in step S304, when laser shock strengthening compensation is performed on each defect point in each defect area of ​​each compensation zone in sequence, the average ablation depth h1 of the absorption layer in each defect area is used as the basis for the calculation. C Determine the laser shock strengthening compensation parameters for each defect point within the defect area. These parameters include pulse energy E, pulse frequency ε, pulse width t, and the expected ablation depth h2 of the absorption layer. Assuming the workpiece absorption layer thickness is h, determine whether the remaining absorption layer thickness at each defect point supports the laser shock strengthening compensation process based on the expected ablation depth h2 in the compensation parameters for each defect point.

[0018] If the remaining thickness of the absorption layer at each defect point in the defect area satisfies h-h1>h2, then the laser shock strengthening compensation parameters are used to directly perform laser shock strengthening compensation at each defect point in the defect area.

[0019] If the remaining thickness of the absorption layer at each defect point satisfies h-h1≤h2, then tear off the absorption layer on the workpiece, and then proceed with the following steps:

[0020] S401. On the workpiece, take the defect point with the minimum sound signal intensity λ as the central defect area and expand outward to form a compensation area. Ensure that each point in the outermost expansion area is a non-defect point. Then, in the same manner, establish compensation areas for other defect points not included in the above compensation area.

[0021] S402. Sequentially measure the deformation depth h3 at each point within each region of the compensation zone on the workpiece, and calculate the average value h3 of the deformation depth of each region. C ;

[0022] S403. Set the difference range value η0, and set the average value h3 of the deformation depth of each extended area in each compensation zone. C The average value h3 of the deformation depth of the central defect region C The difference η is compared with η0. When |η|≥η0, the extended area is determined to be a nearby defect area. The difference range value η0 is obtained by taking the average value of multiple sets of tests under the same conditions.

[0023] S404. After laying the new absorption layer, based on the average deformation depth h3 of each defect area. CDetermine the laser shock enhancement compensation parameters for each defect point within the defect area. The laser shock enhancement compensation parameters include pulse energy E, pulse frequency ε, and pulse width t.

[0024] S405. Laser shock reinforcement compensation is performed sequentially on each defect point within each defect area of ​​each compensation zone.

[0025] The laser shock enhancement compensation parameters are obtained by averaging multiple sets of tests under the same conditions.

[0026] Furthermore, before the workpiece is subjected to laser shock strengthening, a unique serial number is generated for each point to be strengthened, and the serial number of each point corresponds to the information of each point.

[0027] Another technical solution of the present invention to solve the technical problem is as follows:

[0028] This invention discloses a defect compensation system for laser shock peening processes, comprising:

[0029] The laser control unit is used to receive laser shock strengthening parameters or laser shock strengthening compensation parameters and output the corresponding laser beam to complete laser shock strengthening or laser shock strengthening compensation for the corresponding points to be strengthened or the defect points to be compensated on the workpiece.

[0030] The robotic arm control unit is used to determine and output the position and pose information of each point to be strengthened on the workpiece, as well as to clamp the workpiece and adjust its position and posture. It works in conjunction with the laser control unit to complete laser shock strengthening or laser shock strengthening compensation for each point to be strengthened or each defect point to be compensated on the workpiece.

[0031] The impact strengthening process monitoring unit is used to acquire and output the acoustic signal intensity λ generated by the laser control unit when laser shock strengthening is completed on each point of the workpiece to be strengthened.

[0032] The process control unit is used to receive the input absorption layer thickness parameter h and laser shock strengthening parameters, receive the position and pose information of each point to be strengthened on the workpiece output by the robotic arm control unit, and send the corresponding laser shock strengthening parameters and position and pose information of each point to be strengthened to the laser control unit and the robotic arm control unit, respectively, and control the laser control unit and the robotic arm control unit to cooperate in completing the laser shock strengthening of each point to be strengthened; and to receive the acoustic signal intensity λ generated by the laser control unit when completing the laser shock strengthening of each point to be strengthened on the workpiece, output by the shock strengthening process monitoring unit, and receive the input normal acoustic signal intensity λ determined by the pre-sample. C And the lower limit difference 'a' obtained by averaging multiple sets of tests under the same conditions, comparing the sound signal intensity λ with the normal sound signal intensity λ C Compare, if there exists λ < λ CIf -a is selected, this point is determined to be a defect point and the defect point information is output. After all defect points are determined, the information of each defect point is analyzed and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are controlled to cooperate to complete the laser shock enhancement compensation of each defect point.

[0033] Furthermore, the impact strengthening process monitoring unit is also used to acquire and output the acoustic signal intensity λ generated by the laser control unit when performing laser impact strengthening compensation on each defect point of the workpiece; the process control unit is also used to receive the acoustic signal intensity λ generated by the laser control unit when performing laser impact strengthening compensation on each defect point of the workpiece, output by the impact strengthening process monitoring unit, and to receive the normal acoustic signal intensity λ determined by pre-sampling. C And the lower limit difference 'a' obtained by averaging multiple sets of tests under the same conditions, comparing the sound signal intensity λ with the normal sound signal intensity λ C Compare, if there exists λ < λ C If -a is selected, the point is determined to be a defect point and the defect point location is output. After all defect points are determined, the information of each defect point is analyzed and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are then controlled to cooperate to complete the laser shock enhancement compensation of each defect point.

[0034] Furthermore, the robotic arm control unit generates unique serial numbers corresponding to the position and pose information of each point on the workpiece to be strengthened.

[0035] Furthermore, it also includes an impact strengthening defect detection unit, which, after all defect points are determined, acquires and generates a three-dimensional contour of the absorption layer on the workpiece. A compensation zone is formed by taking the defect point with the minimum acoustic signal intensity λ as the central defect area and sequentially expanding outwards to form multiple areas. This ensures that all points within the outermost expansion area are non-defect points. Compensation zones are then sequentially established for other defect points not included in the aforementioned compensation zone in the same manner. The ablation depth h1 of the absorption layer at each point within each compensation zone is measured sequentially, and the average ablation depth h1 of the absorption layer in each region is calculated. C The difference range δ0 obtained by averaging multiple sets of tests under the same conditions is used to calculate the average ablation depth h1 of the absorption layer in each extended region of the compensation zone. C The average ablation depth h1 of the absorption layer in the central defect region CThe difference δ and δ0 are compared. When |δ|≥δ0, the extended area is determined to be a nearby defect area. After all the nearby defect areas of each compensation area are determined, the information of each defect point in each defect area of ​​each compensation area is output to the process control unit. The process control unit determines the laser shock enhancement compensation parameters according to the information of each defect point in each defect area of ​​each compensation area, and sends the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point to the laser control unit and the robotic arm control unit respectively, and controls the laser control unit and the robotic arm control unit to cooperate to complete the laser shock enhancement compensation of each defect point in each defect area of ​​each compensation area.

[0036] Furthermore, the process control unit calculates the ablation depth h1 of the absorption layer in each defect region of each compensation zone. C The laser shock peening compensation parameters for each defect point within the defect area are determined. These parameters are obtained by averaging multiple sets of experiments under identical conditions. The laser shock peening compensation parameters include pulse energy E, pulse frequency ε, pulse width t, and expected ablation depth h2 of the absorption layer. Based on the expected ablation depth h2, the already ablated depth h1, and the absorption layer thickness h of each defect point's compensation parameters, it is determined whether the remaining absorption layer thickness at each defect point to be strengthened supports the laser shock peening compensation process.

[0037] If the remaining thickness of the absorption layer at each defect point in the defect area satisfies h-h1>h2, the process control unit directly sends the laser shock enhancement compensation parameters and position and attitude information corresponding to each defect point to the laser control unit and the robotic arm control unit respectively, and controls the laser control unit and the robotic arm control unit to cooperate to complete the laser shock enhancement compensation of each defect point in each defect area of ​​each compensation zone.

[0038] If the remaining thickness of the absorption layer at each defect point satisfies h-h1≤h2, the absorption layer on the workpiece is removed. Then, the three-dimensional contour of the workpiece after deformation is acquired and generated by the impact strengthening defect detection unit. The defect point with the minimum acoustic signal intensity λ is taken as the central defect area, and multiple areas are successively expanded outward to form a compensation area. It is ensured that each point in the outermost expansion area is a non-defect point. Then, compensation areas are successively established for other defect points not included in the above compensation area in the same way. The deformation depth h3 of each point in each area of ​​each compensation area on the workpiece is measured in sequence, and the average value h3 of the deformation depth of each area is calculated. C The difference range value η0 obtained by averaging multiple sets of tests under the same conditions is used to calculate the average deformation depth h3 of each extended region in each compensation zone. C The average value h3 of the deformation depth of the central defect region CThe difference η and η0 are compared. When |η|≥η0, the extended area is determined to be a nearby defect area. After all nearby defect areas in each compensation area are determined, the information of each defect point in each defect area of ​​each compensation area is output to the process control unit. The process control unit calculates the information based on the average deformation depth h3 of each defect area. C The laser shock enhancement compensation parameters for each defect point within the defect area are determined, and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are controlled to cooperate to complete the laser shock enhancement compensation for each defect point in each defect area of ​​each compensation zone. The laser shock enhancement compensation parameters are obtained by averaging multiple sets of tests under the same conditions. The laser shock enhancement compensation parameters include pulse energy E, pulse frequency ε and pulse width t.

[0039] Furthermore, it also includes a process database unit for storing various laser shock strengthening compensation parameters. These parameters are obtained in advance through laser shock strengthening tests on workpieces of various specifications, absorption layers, and the average ablation depth of various absorption layers and the average deformation depth of the workpiece surface. The process control unit matches the data stored in the process database unit with the average ablation depth of the absorption layer or the average deformation depth of the workpiece surface in each defect area of ​​each compensation zone.

[0040] Compared with the prior art, the defect compensation method and system for laser shock peening process described in this invention have the following advantages:

[0041] (1) This invention compares the acoustic signal intensity λ of each point of the workpiece to be strengthened during laser shock strengthening with the normal acoustic signal intensity λ determined by pre-sampling. C By comparing the results and setting an appropriate lower limit difference value 'a', it is possible to quickly determine whether each reinforcement point is a defect point.

[0042] (2) By measuring the ablation depth of the absorption layer in each defect area and its adjacent area, the present invention can quickly divide the defect area and the non-defect area, which facilitates the rapid determination of the laser shock strengthening compensation parameters based on the average ablation depth of the absorption layer in each defect area, and performs precise compensation for each defect point in each defect area where the remaining thickness of the absorption layer meets the conditions. At the same time, for each defect point in each defect area where the remaining thickness of the absorption layer meets the conditions, the absorption layer is removed and a similar method is used in the working deformation area to quickly divide the defect area and the non-defect area, and the laser shock strengthening compensation parameters are quickly determined based on the average deformation depth of each defect area for precise compensation.

[0043] (4) The present invention generates a unique serial number corresponding to each point of the workpiece to be strengthened. The serial number of each point corresponds to the information of each point, which facilitates the recording and processing of information of each point of the workpiece.

[0044] (5) The present invention stores the data obtained from the laser shock strengthening test under the conditions of the average ablation depth of various types of absorption layers and the average deformation depth of the workpiece surface in the process database unit in advance, so as to facilitate rapid matching according to the actual situation of each defect point area. Attached Figure Description

[0045] Figure 1 This is a schematic flowchart of the defect compensation method for laser shock strengthening process described in this invention;

[0046] Figure 2 This is a schematic diagram of the defect compensation system for the laser shock strengthening process described in this invention;

[0047] Figure 3 This is a schematic diagram illustrating the basic principle of laser shock peening (under normal circumstances);

[0048] Figure 4 This is a schematic diagram of laser shock peening (under-strengthening);

[0049] Figure 5 This is a schematic diagram of laser shock peening (single-parameter compensation peening);

[0050] Figure 6 This is a schematic diagram of laser shock peening (intelligent compensation peening);

[0051] Figure 7 This is a schematic diagram illustrating the division of defective and non-defective regions at the deformation site on the absorption layer or workpiece in this invention.

[0052] Figure 8 This is a table of compensation parameters for two different ablation thicknesses of the absorption layer in this invention;

[0053] In the diagram: 101, Laser control unit; 102, Airborne arm control unit; 103, Impact strengthening process monitoring unit; 104, Process control unit; 105, Impact strengthening defect detection unit; 106, Process database unit. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains. The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “inner,” “outer,” “horizontal,” and “vertical” as used in this patent application specification and claims are used only to indicate relative positional relationships; these relative positional relationships change accordingly when the absolute position of the described object changes. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. All aspects not detailed herein are well-known to those skilled in the art.

[0056] Example 1:

[0057] like Figure 1 , 6 As shown in Figure 7, the present invention provides a defect compensation method for laser shock peening process, which includes the following steps:

[0058] S1. When the workpiece is subjected to the first laser shock strengthening, the acoustic signal intensity λ of each point to be strengthened on the workpiece during laser shock strengthening is obtained.

[0059] S2. Sequentially compare each of the aforementioned acoustic signal intensities λ with the pre-sampled normal acoustic signal intensity λ. C The normal acoustic signal intensity λ was compared. C By conducting multiple experiments with the same workpiece specifications and laser shock strengthening parameters, and obtaining the acoustic signal intensity of each point to be strengthened and taking the average value, a lower limit difference 'a' is set. If λ < λ, then... C If -a is found, then this point is determined to be a defect point (under-reinforcement). The lower limit difference 'a' is obtained by averaging multiple sets of tests under the same conditions, which is also the normal sound signal intensity λ. C The average value is obtained by taking the difference between the acoustic signal intensity at each strengthening point in each group of tests when the acoustic signal intensity is at the critical state between defects and non-defects. The same conditions mentioned refer to the conditions that the workpiece specifications, laser shock strengthening parameters, etc. are all consistent.

[0060] S3. If the aforementioned defect points exist, laser shock reinforcement compensation shall be performed on each defect point.

[0061] In this embodiment, when performing laser shock strengthening compensation on each of the aforementioned defect points, the acoustic signal intensity λ of each defect point on the workpiece during laser shock strengthening compensation is continuously acquired. The system continues to monitor whether defect points still exist using the method described in step S2, and laser shock strengthening compensation is performed on any remaining defect points. This process continues until compensation is complete. Compensation completion means that no defect point has λ < λ. C In the case of –a, or after compensation, if λ < λC -a The number of defect points does not exceed 5% of the total number of laser shock strengthening points on the workpiece. Through the above-mentioned multiple precise laser shock strengthenings, the workpiece can reach the same level as the first laser shock strengthening effect.

[0062] In this embodiment, when performing laser shock strengthening compensation on each of the defect points in step S3, the following steps are performed:

[0063] S301. On the workpiece, take the defect point with the minimum sound signal intensity λ as the central defect area and expand outward to form a compensation area. Ensure that each point in the outermost expansion area is a non-defect point. Then, in the same manner, establish compensation areas for other defect points not included in the above compensation area.

[0064] S302. Sequentially measure the ablation depth h1 of each point in each region of the compensation zone corresponding to the absorption layer position, and calculate the average ablation depth h1 of the absorption layer in each region. C ;

[0065] S303. Set an appropriate difference range value δ0, and set the average ablation depth h1 of the absorption layer in each extended region of each compensation zone. C The average ablation depth h1 of the absorption layer in the central defect region C The difference δ is compared with δ0. When |δ|≥δ0, the extended area is determined to be a nearby defect area. The difference range value δ0 is obtained by taking the average value of multiple sets of tests under the same conditions in advance, which is similar to the method of obtaining the lower limit difference value a in step S2.

[0066] S304. Laser shock reinforcement compensation is performed sequentially on each defect point in each defect area of ​​each compensation zone.

[0067] Figure 7 The diagram shows an example of the division of defective and non-defective regions on the absorption layer. Region ① is the central defective region, regions ②, ③, and ④ are extended regions, regions ② and ③ are adjacent defective regions, and region ④ and the region outside it are non-defective regions. Typically, the degree of defect in regions ①, ②, and ③ decreases sequentially.

[0068] In this embodiment, during step S304, when laser shock peening compensation is performed sequentially on each defect point within each defect area of ​​each compensation zone, the average ablation depth h1 of the absorption layer in each defect area is used as the basis for the calculation. C Determine the laser shock strengthening compensation parameters for each defect point within the defect area. These parameters include pulse energy E, pulse frequency ε, pulse width t, and the expected ablation depth h2 of the absorption layer. Assuming the workpiece absorption layer thickness is h, determine whether the remaining absorption layer thickness at each defect point supports the laser shock strengthening compensation process based on the expected ablation depth h2 in the compensation parameters for each defect point.

[0069] If the remaining thickness of the absorption layer at each defect point in the defect area satisfies h-h1>h2, that is, the remaining thickness of the absorption layer satisfies the ablation requirement during compensation, then the laser shock strengthening compensation parameters are used to directly perform laser shock strengthening compensation at each defect point in the defect area.

[0070] If the remaining thickness of the absorption layer at each defect point satisfies h-h1≤h2, meaning the remaining thickness of the absorption layer does not meet the ablation requirements for compensation, then the absorption layer on the workpiece should be removed, and the following steps should be followed:

[0071] S401. On the workpiece, take the defect point with the minimum sound signal intensity λ as the central defect area and expand outward to form a compensation area. Ensure that each point in the outermost expansion area is a non-defect point. Then, in the same manner, establish compensation areas for other defect points not included in the above compensation area.

[0072] S402. Sequentially measure the deformation depth h3 at each point within each region of the compensation zone on the workpiece, and calculate the average value h3 of the deformation depth of each region. C ;

[0073] S403. Set a suitable difference range value η0, and set the average value h3 of the deformation depth of each extended area in each compensation zone. C The average value h3 of the deformation depth of the central defect region C The difference η is compared with η0. When |η|≥η0, the extended area is determined to be a nearby defect area. The difference range value η0 is obtained by taking the average of multiple sets of tests under the same conditions, which is similar to the method of obtaining the lower limit difference value a and the difference range value δ0 mentioned above.

[0074] S404. After laying the new absorption layer, based on the average deformation depth h3 of each defect area. C Determine the laser shock enhancement compensation parameters for each defect point within the defect area. The laser shock enhancement compensation parameters include pulse energy E, pulse frequency ε, and pulse width t.

[0075] S405. Laser shock reinforcement compensation is performed sequentially on each defect point within each defect area of ​​each compensation zone.

[0076] In this embodiment, the laser shock enhancement compensation parameters are obtained by averaging multiple sets of tests under the same conditions.

[0077] In this embodiment, the laser shock enhancement compensation parameters obtained through experiments under various conditions can be stored in a database for matching and retrieval based on actual circumstances. The lower limit difference 'a', difference range value 'δ0', and difference range value 'η0' obtained through experiments under various conditions can also be stored for reference when similar situations occur.

[0078] In this embodiment, before the workpiece is subjected to laser shock strengthening, a unique serial number is generated for each point to be strengthened. The serial number of each point corresponds to the information of each point, which facilitates the recording of information of each point. Figure 8 The information for two indexed points is shown. Point number 1 has a value λ < λ. C –a, the absorber layer thickness h is 200 μm, the expected ablation depth h2 is 100 μm, and the average ablation depth h1 of the absorber layer. C If the value is 80 μm and satisfies h - h1 > h2, then laser enhancement compensation can be performed after matching appropriate compensation parameters. Point 2 also exhibits λ < λ. C –a, the absorber layer thickness h is 200 μm, the expected ablation depth h2 is 100 μm, and the average ablation depth h1 of the absorber layer. C If the depth is 120μm, and the condition h-h1>h2 is not met, then the absorption layer needs to be removed, and then appropriate compensation parameters should be matched according to the average depth of the workpiece deformation before laser strengthening compensation is performed.

[0079] Figure 6 The image shows a workpiece after precise compensation, which can achieve the same level of effect as the first laser shock peening.

[0080] Example 2:

[0081] like Figure 1-2 As shown, the present invention provides a defect compensation system for laser shock peening processes, comprising:

[0082] The laser control unit 101 typically includes a laser and a laser controller. The laser controller is used to receive laser shock strengthening parameters or laser shock strengthening compensation parameters and control the laser to output the corresponding laser beam to complete laser shock strengthening or laser shock strengthening compensation for the corresponding points to be strengthened or the defect points to be compensated on the workpiece.

[0083] The robotic arm control unit 102 typically includes a robotic arm and a robotic arm controller. The robotic arm is usually equipped with a camera device for recognizing the workpiece. The robotic arm controller is used to determine and output the position and pose information of each point on the workpiece to be strengthened, and to control the robotic arm to hold the workpiece and adjust the position and posture of the workpiece. It works in conjunction with the laser control unit to complete laser shock strengthening or laser shock strengthening compensation of each point on the workpiece to be strengthened or each defect point to be compensated. The robotic arm control unit can also be replaced by a robot.

[0084] The impact strengthening process monitoring unit 103 is used to acquire and output the acoustic signal intensity λ generated by the laser control unit when laser shock strengthening is completed on each point of the workpiece. It can use an acoustic signal acquisition device to output the acoustic signal during the laser shock strengthening process through an oscilloscope, fit the waveform after fast Fourier transform, and then output the acoustic signal intensity λ.

[0085] The process control unit 104 is used to receive input parameters such as the absorption layer thickness h and laser shock strengthening parameters, and to receive the position and orientation information of each point to be strengthened on the workpiece output by the robotic arm control unit. It also sends the corresponding laser shock strengthening parameters and position and orientation information of each point to be strengthened to the laser control unit and the robotic arm control unit, respectively, and controls the laser control unit and the robotic arm control unit to cooperate in completing the laser shock strengthening of each point to be strengthened. Furthermore, it is used to receive the acoustic signal intensity λ generated by the laser control unit during laser shock strengthening of each point on the workpiece, output by the shock strengthening process monitoring unit, and to receive the normal acoustic signal intensity λ determined by pre-sampling. C And the lower limit difference 'a' obtained by averaging multiple sets of tests under the same conditions, comparing the sound signal intensity λ with the normal sound signal intensity λ C Compare, if there exists λ < λ C If -a is selected, this point is determined to be a defect point and the defect point information is output. After all defect points are determined, the information of each defect point is analyzed and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are controlled to cooperate to complete the laser shock enhancement compensation of each defect point.

[0086] In this embodiment, the impact strengthening process monitoring unit is further configured to acquire and output the acoustic signal intensity λ generated by the laser control unit when performing laser impact strengthening compensation on each defect point of the workpiece; the process control unit is further configured to receive the acoustic signal intensity λ generated by the laser control unit when performing laser impact strengthening compensation on each defect point of the workpiece, output by the impact strengthening process monitoring unit, and receive the normal acoustic signal intensity λ determined by pre-sampling. C And the lower limit difference 'a' obtained by averaging multiple sets of tests under the same conditions, comparing the sound signal intensity λ with the normal sound signal intensity λ C Compare, if there exists λ < λ C If -a is selected, the point is determined to be a defect point and the defect point location is output. After all defect points are determined, the information of each defect point is analyzed and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are then controlled to cooperate to complete the laser shock enhancement compensation of each defect point.

[0087] In this embodiment, the robotic arm control unit generates unique serial numbers corresponding to the position and pose information of each point to be strengthened on the workpiece, which facilitates the recording of information for each point.

[0088] In this embodiment, an impact strengthening defect detection unit 105 is also included. After all defect points are determined, a three-dimensional contour acquisition device is used to acquire and generate a three-dimensional contour of the absorption layer on the workpiece. The defect point with the lowest acoustic signal intensity λ is taken as the central defect area, and multiple areas are sequentially expanded outward to form a compensation area. It is ensured that all points in the outermost expansion area are non-defect points. Then, compensation areas are sequentially established for other defect points not included in the above compensation area in the same manner. The ablation depth h1 of the absorption layer position corresponding to each point in each area of ​​each compensation area is measured sequentially, and the average value h1 of the ablation depth of the absorption layer in each area is calculated. C The difference range δ0 obtained by averaging multiple sets of tests under the same conditions is used to calculate the average ablation depth h1 of the absorption layer in each extended region of the compensation zone. C The average ablation depth h1 of the absorption layer in the central defect region C The difference δ and δ0 are compared. When |δ|≥δ0, the extended area is determined to be a nearby defect area. After all the nearby defect areas of each compensation area are determined, the information of each defect point in each defect area of ​​each compensation area is output to the process control unit. The process control unit determines the laser shock enhancement compensation parameters according to the information of each defect point in each defect area of ​​each compensation area, and sends the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point to the laser control unit and the robotic arm control unit respectively, and controls the laser control unit and the robotic arm control unit to cooperate to complete the laser shock enhancement compensation of each defect point in each defect area of ​​each compensation area.

[0089] In this embodiment, the process control unit uses the average ablation depth h1 of the absorption layer in each defect region of each compensation zone. C The laser shock peening compensation parameters for each defect point within the defect area are determined. These parameters are obtained by averaging multiple sets of experiments under identical conditions. The laser shock peening compensation parameters include pulse energy E, pulse frequency ε, pulse width t, and expected ablation depth h2 of the absorption layer. Based on the expected ablation depth h2, the already ablated depth h1, and the absorption layer thickness h of each defect point's compensation parameters, it is determined whether the remaining absorption layer thickness at each defect point to be strengthened supports the laser shock peening compensation process.

[0090] If the remaining thickness of the absorption layer at each defect point in the defect area satisfies h-h1>h2, the process control unit directly sends the laser shock enhancement compensation parameters and position and attitude information corresponding to each defect point to the laser control unit and the robotic arm control unit respectively, and controls the laser control unit and the robotic arm control unit to cooperate to complete the laser shock enhancement compensation of each defect point in each defect area of ​​each compensation zone.

[0091] If the remaining thickness of the absorption layer at each defect point satisfies h-h1≤h2, the absorption layer on the workpiece is removed. Then, the three-dimensional contour of the workpiece after deformation is acquired and generated by the impact strengthening defect detection unit. The defect point with the minimum acoustic signal intensity λ is taken as the central defect area, and multiple areas are successively expanded outward to form a compensation area. It is ensured that each point in the outermost expansion area is a non-defect point. Then, compensation areas are successively established for other defect points not included in the above compensation area in the same way. The deformation depth h3 of each point in each area of ​​each compensation area on the workpiece is measured in sequence, and the average value h3 of the deformation depth of each area is calculated. C The difference range value η0 obtained by averaging multiple sets of tests under the same conditions is used to calculate the average deformation depth h3 of each extended region in each compensation zone. C The average value h3 of the deformation depth of the central defect region C The difference η and η0 are compared. When |η|≥η0, the extended area is determined to be a nearby defect area. After all nearby defect areas in each compensation area are determined, the information of each defect point in each defect area of ​​each compensation area is output to the process control unit. The process control unit calculates the information based on the average deformation depth h3 of each defect area. C The laser shock enhancement compensation parameters for each defect point within the defect area are determined, and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are controlled to cooperate to complete the laser shock enhancement compensation for each defect point in each defect area of ​​each compensation zone. The laser shock enhancement compensation parameters are obtained by averaging multiple sets of tests under the same conditions. The laser shock enhancement compensation parameters include pulse energy E, pulse frequency ε and pulse width t.

[0092] In this embodiment, a process database unit 106 is also included to store various laser shock strengthening compensation parameters. These parameters are obtained in advance through laser shock strengthening tests on workpieces of various specifications, absorption layers, and the average ablation depth of various absorption layers and the average deformation depth of the workpiece surface. The process control unit matches the data stored in the process database unit with the average ablation depth of the absorption layer or the average deformation depth of the workpiece surface in each defect area of ​​each compensation zone.

Claims

1. A method for defect compensation in a laser shock peening process, characterized in that, Includes the following steps: S1. Obtain the acoustic signal intensity λ of each point of the workpiece to be strengthened during laser shock strengthening; S2. Sequentially compare each of the aforementioned acoustic signal intensities λ with the pre-sampled normal acoustic signal intensity λ. C Compare the values, set a lower limit difference a, and if there exists λ < λ C If -a, then this point is determined to be a defect point. The lower limit difference a is obtained by taking the average value of multiple sets of tests under the same conditions in advance. S3. If the aforementioned defect points exist, laser shock reinforcement compensation shall be performed on each defect point. When performing laser shock strengthening compensation on each of the aforementioned defect points, the acoustic signal intensity λ of each defect point on the workpiece during laser shock strengthening compensation is continuously acquired, and whether there are still defect points is monitored through the method described in step S2. Laser shock strengthening compensation is then performed on the remaining defect points, and the above method is used until the compensation is completed. When performing laser shock strengthening compensation on each of the defect points in S3, the following steps are performed: S301. On the workpiece, take the defect point with the minimum sound signal intensity λ as the central defect area and expand outward to form a compensation area. Ensure that each point in the outermost expansion area is a non-defect point. Then, in the same manner, establish compensation areas for other defect points not included in the above compensation area. S302. Sequentially measure the ablation depth h1 of each point in each region of the compensation zone corresponding to the absorption layer position, and calculate the average ablation depth h1 of the absorption layer in each region. C ; S303. Set the difference range value δ0, and set the average value h1 of the ablation depth of the absorption layer in each extended area of ​​each compensation zone. C The average ablation depth h1 of the absorption layer in the central defect region C The difference δ is compared with δ0. When |δ|≥δ0, the extended area is determined to be a nearby defect area. The difference range value δ0 is obtained by taking the average value of multiple sets of tests under the same conditions. S304. Laser shock reinforcement compensation is performed sequentially on each defect point in each defect area of ​​each compensation zone.

2. The defect compensation method for laser shock peening process according to claim 1, characterized in that, In step S304, when laser shock strengthening compensation is performed on each defect point in each defect area of ​​each compensation zone in sequence, the average ablation depth h1 of the absorption layer in each defect area is used as the basis for the calculation. C Determine the laser shock strengthening compensation parameters for each defect point within the defect area. These parameters include pulse energy E, pulse frequency ε, pulse width t, and the expected ablation depth h2 of the absorption layer. Assuming the workpiece absorption layer thickness is h, determine whether the remaining absorption layer thickness at each defect point supports the laser shock strengthening compensation process based on the expected ablation depth h2 in the compensation parameters for each defect point. If the remaining thickness of the absorption layer at each defect point in the defect area satisfies h-h1>h2, then the laser shock strengthening compensation parameters are used to directly perform laser shock strengthening compensation at each defect point in the defect area. If the remaining thickness of the absorption layer at each defect point satisfies h-h1≤h2, then tear off the absorption layer on the workpiece, and then proceed with the following steps: S401. On the workpiece, take the defect point with the minimum sound signal intensity λ as the central defect area and expand outward to form a compensation area. Ensure that each point in the outermost expansion area is a non-defect point. Then, in the same manner, establish compensation areas for other defect points not included in the above compensation area. S402. Sequentially measure the deformation depth h3 at each point within each region of the compensation zone on the workpiece, and calculate the average value h3 of the deformation depth of each region. C ; S403. Set the difference range value η0, and set the average value h3 of the deformation depth of each extended area in each compensation zone. C The average value h3 of the deformation depth of the central defect region C The difference η is compared with η0. When |η|≥η0, the extended area is determined to be a nearby defect area. The difference range value η0 is obtained by taking the average value of multiple sets of tests under the same conditions. S404. After laying the new absorption layer, based on the average deformation depth h3 of each defect area... C Determine the laser shock enhancement compensation parameters for each defect point within the defect area. The laser shock enhancement compensation parameters include pulse energy E, pulse frequency ε, and pulse width t. S405. Laser shock enhancement compensation is performed sequentially on each defect point in each defect area of ​​each compensation zone. The laser shock enhancement compensation parameters are obtained by averaging multiple sets of tests under the same conditions.

3. The defect compensation method for laser shock peening process according to claim 1, characterized in that, Before the workpiece is subjected to laser shock strengthening, a unique serial number is generated for each point to be strengthened, and the serial number of each point corresponds to the information of each point.

4. A defect compensation system for laser shock peening process, characterized in that, include: The laser control unit is used to receive laser shock strengthening parameters or laser shock strengthening compensation parameters and output the corresponding laser beam to complete laser shock strengthening or laser shock strengthening compensation for the corresponding points to be strengthened or the defect points to be compensated on the workpiece. The robotic arm control unit is used to determine and output the position and pose information of each point to be strengthened on the workpiece, as well as to clamp the workpiece and adjust its position and posture. It works in conjunction with the laser control unit to complete laser shock strengthening or laser shock strengthening compensation for each point to be strengthened or each defect point to be compensated on the workpiece. The impact strengthening process monitoring unit is used to acquire and output the acoustic signal intensity λ generated by the laser control unit when laser shock strengthening is completed on each point of the workpiece to be strengthened. The process control unit is used to receive the input absorption layer thickness parameter h and laser shock strengthening parameters, receive the position and pose information of each point to be strengthened on the workpiece output by the robotic arm control unit, and send the corresponding laser shock strengthening parameters and position and pose information of each point to be strengthened to the laser control unit and the robotic arm control unit, respectively, and control the laser control unit and the robotic arm control unit to cooperate in completing the laser shock strengthening of each point to be strengthened; and to receive the acoustic signal intensity λ generated by the laser control unit when completing the laser shock strengthening of each point to be strengthened on the workpiece, output by the shock strengthening process monitoring unit, and receive the input normal acoustic signal intensity λ determined by the pre-sample. C And the lower limit difference 'a' obtained by averaging multiple sets of tests under the same conditions, comparing the sound signal intensity λ with the normal sound signal intensity λ C Compare, if there exists λ < λ C - a, then this point is determined to be a defect point and the defect point information is output. After all defect points are determined, the information of each defect point is analyzed and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are controlled to cooperate to complete the laser shock enhancement compensation of each defect point. The impact strengthening process monitoring unit is also used to acquire and output the acoustic signal intensity λ generated by the laser control unit when performing laser impact strengthening compensation on each defect point of the workpiece; the process control unit is also used to receive the acoustic signal intensity λ generated by the laser control unit when performing laser impact strengthening compensation on each defect point of the workpiece, output by the impact strengthening process monitoring unit, and receive the normal acoustic signal intensity λ determined by the pre-sampling. C And the lower limit difference 'a' obtained by averaging multiple sets of tests under the same conditions, comparing the sound signal intensity λ with the normal sound signal intensity λ C Compare, if there exists λ < λ C If -a, then this point is determined to be a defect point and the defect point position is output. After all defect points are determined, the information of each defect point is analyzed and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are controlled to cooperate to complete the laser shock enhancement compensation of each defect point.

5. A defect compensation system for laser shock peening process according to claim 4, characterized in that, The robotic arm control unit generates unique serial numbers corresponding to the position and pose information of each point on the workpiece to be strengthened.

6. A defect compensation system for laser shock peening process according to claim 4, characterized in that, It also includes an impact strengthening defect detection unit, which, after all defect points are determined, acquires and generates a three-dimensional contour of the absorption layer on the workpiece. A compensation zone is formed by taking the defect point with the lowest acoustic signal intensity λ as the central defect area and sequentially expanding outwards to form multiple areas. This ensures that all points within the outermost expansion area are non-defect points. Compensation zones are then sequentially established for other defect points not included in the aforementioned compensation zone in the same manner. The ablation depth h1 of the absorption layer at each point within each compensation zone is measured sequentially, and the average ablation depth h1 of the absorption layer in each region is calculated. C The difference range δ0 obtained by averaging multiple sets of tests under the same conditions is used to calculate the average ablation depth h1 of the absorption layer in each extended region of the compensation zone. C The average ablation depth h1 of the absorption layer in the central defect region C The difference δ and δ0 are compared. When |δ|≥δ0, the extended region is determined to be a region adjacent to the defect. After all adjacent defect areas in each compensation zone have been determined, the information of each defect point in each defect area of ​​each compensation zone is output to the process control unit. The process control unit determines the laser shock enhancement compensation parameters based on the information of each defect point in each defect area of ​​each compensation zone, and sends the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point to the laser control unit and the robotic arm control unit respectively, so as to control the laser control unit and the robotic arm control unit to cooperate in completing the laser shock enhancement compensation of each defect point in each defect area of ​​each compensation zone.

7. A defect compensation system for laser shock peening process according to claim 6, characterized in that, The process control unit is based on the average ablation depth h1 of the absorption layer in each defect region of each compensation zone. C The laser shock peening compensation parameters for each defect point within the defect area are determined. These parameters are obtained by averaging multiple sets of experiments under identical conditions. The laser shock peening compensation parameters include pulse energy E, pulse frequency ε, pulse width t, and expected ablation depth h2 of the absorption layer. Based on the expected ablation depth h2, the already ablated depth h1, and the absorption layer thickness h of each defect point's compensation parameters, it is determined whether the remaining absorption layer thickness at each defect point to be strengthened supports the laser shock peening compensation process. If the remaining thickness of the absorption layer at each defect point in the defect area satisfies h-h1>h2, the process control unit directly sends the laser shock enhancement compensation parameters and position and attitude information corresponding to each defect point to the laser control unit and the robotic arm control unit respectively, and controls the laser control unit and the robotic arm control unit to cooperate to complete the laser shock enhancement compensation of each defect point in each defect area of ​​each compensation zone. If the remaining thickness of the absorption layer at each defect point satisfies h-h1≤h2, the absorption layer on the workpiece is removed. Then, the three-dimensional contour of the workpiece after deformation is acquired and generated by the impact strengthening defect detection unit. A compensation zone is formed by taking the defect point with the minimum acoustic signal intensity λ as the central defect area and expanding outwards to form multiple areas. It is ensured that all points in the outermost expansion area are non-defect points. Then, compensation zones are established sequentially for other defect points not included in the above compensation zone in the same way. The deformation depth h3 of each point in each area of ​​each compensation zone on the workpiece is measured sequentially, and the average value h3 of the deformation depth of each area is calculated. C The difference range value η0 obtained by averaging multiple sets of tests under the same conditions is used to calculate the average deformation depth h3 of each extended region in each compensation zone. C The average value h3 of the deformation depth of the central defect region C The difference η and η0 are compared. When |η|≥η0, the extended region is determined to be a region adjacent to the defect. After all adjacent defect areas in each compensation zone have been determined, the information of each defect point in each defect area of ​​each compensation zone is output to the process control unit. The process control unit is based on the average deformation depth h3 of each defect region. C The laser shock enhancement compensation parameters for each defect point within the defect area are determined, and the laser shock enhancement compensation parameters, position and attitude information corresponding to each defect point are sent to the laser control unit and the robotic arm control unit respectively. The laser control unit and the robotic arm control unit are controlled to cooperate to complete the laser shock enhancement compensation for each defect point in each defect area of ​​each compensation zone. The laser shock enhancement compensation parameters are obtained by averaging multiple sets of tests under the same conditions. The laser shock enhancement compensation parameters include pulse energy E, pulse frequency ε and pulse width t.

8. A defect compensation system for laser shock peening process according to claim 7, characterized in that, It also includes a process database unit for storing various laser shock strengthening compensation parameters. These parameters are obtained in advance through laser shock strengthening tests on workpieces of various specifications, absorption layers, and the average ablation depth of various absorption layers and the average deformation depth of the workpiece surface. The process control unit matches the data stored in the process database unit with the average ablation depth of the absorption layer or the average deformation depth of the workpiece surface in each defect area of ​​each compensation zone.

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