Matrix type ultrasonic-assisted liquid guide laser processing system and method

Abstract

The invention belongs to the technical field of laser processing, and particularly relates to a matrix type ultrasonic-assisted liquid guide laser processing system and method.The matrix type ultrasonic-assisted liquid guide laser processing method comprises the steps that a laser module receives a control instruction of an upper computer, outputs a laser beam and focuses the laser beam into a coupling water cavity module; the coupling water cavity module couples an incident laser beam with a water jet in the cavity, and forms a high-pressure water jet to guide the laser to act on the surface of a workpiece; the ultrasonic vibration module is used for forming ultrasonic vibration on the workpiece; the pressure-stabilizing high-pressure water module supplies water to the coupling water cavity module; the CCD machine vision monitoring module collects the position of a light spot focus of the laser beam and sends the position to the upper computer, and the upper computer adjusts the laser module in real time according to the real-time position of the light spot focus and the position of a nozzle of the coupling water cavity module. The influence of high-power ultrasonic vibration on the workpiece clamping stability can be reduced, and therefore high-quality and high-efficiency machining of large-depth-diameter-ratio micropores and surface fine structures of large thin-wall workpieces is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser processing, and specifically relates to a matrix ultrasonic-assisted liquid-guided laser processing system and method. Background Art

[0002] Liquid-guided laser processing is a technology that combines laser processing and water jet processing to achieve microfabrication. The laser is transmitted to the workpiece surface through a water beam to realize the processing of the workpiece. Compared with traditional laser processing, the liquid-guided laser processing technology has the advantages of low thermal damage, long working distance, and high processing accuracy, and has certain advantages in the processing of microholes with large depth-to-diameter ratios and surface microstructures of difficult-to-machine materials (such as hard and brittle materials, composite materials, etc.). During the liquid-guided laser processing process, the material absorbs the laser energy, vaporizes or melts, and leaves the substrate to form material removal. As the processing depth increases, the chip removal condition deteriorates, and the processing products cannot be removed in time. On the one hand, they will splash or deposit on the processing surface to form a recast layer, reducing the processing quality; on the other hand, they will form a barrier, hindering the further transmission of the laser and reducing the processing ability.

[0003] The ultrasonic vibration technology emits high-frequency oscillation signals through an ultrasonic generator, which are converted into high-frequency mechanical oscillations by a transducer and propagated to the processing area. It can promote the separation of the processing products from the substrate, accelerate the discharge of the processing products, and improve the processing surface quality. Usually, there are two ways to use the ultrasonic vibration technology for assisted processing. One is to use media such as water or oil to transfer the mechanical vibration generated by the ultrasonic transducer to the workpiece. However, this transfer method will inevitably consume a large amount of vibration energy in the medium, resulting in insufficient energy transferred to the workpiece to separate the processing products from the substrate. The other is to rigidly connect the ultrasonic transducer to the workpiece, which can directly transfer the mechanical vibration generated by the ultrasonic transducer to the workpiece and reduce energy loss. However, when processing large-sized workpieces, especially large thin-walled workpieces, the vibration of each point on the workpiece is uneven, and it is difficult to ensure the vibration amplitude and vibration frequency at positions far from the vibration source. In order to ensure that the processing area obtains sufficient vibration energy, technicians often use high-power ultrasonic vibration for assisted processing, which affects the clamping stability of the workpiece.

[0004] Aiming at the technical problems that the processing products cannot be removed in time during the liquid-guided laser processing process and the ultrasonic vibration is difficult to be effectively transmitted to the processing area, there is currently no effective method to solve them. Summary of the Invention

[0005] The purpose of the present invention is to provide a matrix ultrasonic-assisted liquid-guided laser processing system and method to overcome the above-mentioned technical problem that the ultrasonic vibration is difficult to be effectively transmitted to the processing area.

[0006] The technical solution adopted by the present invention to achieve the above object is as follows: A matrix ultrasonic-assisted liquid-guided laser processing system, comprising: a host computer and a laser module, a coupling water cavity module, an ultrasonic vibration module, a regulated high-pressure water module, and a CCD machine vision detection and monitoring module connected thereto;

[0007] The laser module is configured to receive a control instruction from the host computer, turn on and output a laser beam of a specific wavelength, and focus it into the coupling water cavity module;

[0008] The coupling water cavity module is disposed below the laser module and is configured to couple the incident laser beam with the water jet in the cavity and form a high-pressure water jet to guide the laser to act on the surface of the workpiece;

[0009] The ultrasonic vibration module is disposed below the coupling water cavity module and is configured to fix the workpiece and simultaneously form ultrasonic vibration on the workpiece;

[0010] The regulated high-pressure water module is connected to the coupling water cavity module and is configured to supply water to the coupling water cavity module and simultaneously adjust the water pressure of the coupling water cavity module;

[0011] The CCD machine vision detection and monitoring module is disposed above the laser module and is configured to collect the position of the light spot focus of the laser beam and send it to the host computer. The host computer adjusts the laser module in real time according to the real-time position of the light spot focus and the nozzle position of the coupling water cavity module to achieve the coincidence of the laser beam and the nozzle of the coupling water cavity module.

[0012] The laser module includes: a laser, a reflecting mirror, and a focusing lens;

[0013] The laser is horizontally fixed on the tooling and is connected to the host computer, receives the control instruction to turn on, and emits a laser beam to the reflecting mirror;

[0014] The emission end of the laser is coaxially arranged with the reflecting mirror; the included angle between the reflecting mirror and the horizontal plane is: 0 degree to 90 degrees, so as to reflect the laser beam emitted by the laser to the focusing lens disposed directly below the reflecting mirror;

[0015] The reflecting mirror is coaxially arranged with the focusing lens; the focusing lens is disposed directly above the coupling water cavity module; by adjusting the rotation angle of the reflecting mirror, the position of the light spot focus in the XY plane is changed, and the Z-direction displacement of the focusing lens is adjusted to achieve the adjustment of the Z-direction position of the light spot focus.

[0016] The coupling water cavity module includes: a window element, a coupling water cavity, and a nozzle;

[0017] The window element is arranged in front of the CCD machine vision inspection module and is coaxially arranged with the field axis of the CCD machine vision inspection module; a reflector and a focusing lens are arranged between the window element and the CCD machine vision inspection module; when the laser beam enters the coupling water cavity through the window element, the Z-direction displacement of the focusing lens is controlled and adjusted by the host computer to make the spot focus coincide with the nozzle center; the water in the coupling water cavity forms a high-pressure water jet through the nozzle, and the high-pressure water jet guides the laser to reach the workpiece surface to achieve material removal.

[0018] The constant-pressure high-pressure water module includes: a water tank, a high-pressure pump, and an overflow valve;

[0019] The water tank is connected to the coupling water cavity through a high-pressure pump and an overflow valve arranged in parallel respectively;

[0020] The high-pressure pump is used to extract water from the water tank and transport it into the coupling water cavity;

[0021] The overflow valve is used to adjust the water pressure in the coupling water cavity.

[0022] The ultrasonic vibration module includes: a vibration plate, an ultrasonic transducer, an ultrasonic generator, a controller, and an amplitude sensor;

[0023] The vibration plate is of a plate-like structure, and an ultrasonic transducer is arranged below the vibration plate; a workpiece is arranged on the vibration plate, and the vibration plate is rigidly connected to the workpiece;

[0024] The controller is connected to the ultrasonic transducer through the ultrasonic generator, and is used to control the ultrasonic transducer to generate ultrasonic vibration and transmit it to the vibration plate;

[0025] The ultrasonic generator is used to generate a high-frequency alternating current signal and transmit it to the ultrasonic transducer;

[0026] The amplitude sensor is fixedly arranged above the workpiece and is connected to the controller, and is used to collect the vibration signal on the workpiece and feedback it to the controller; the controller adjusts the ultrasonic generator according to the real-time vibration signal;

[0027] The ultrasonic transducers are arranged in an m×n matrix below the vibration plate, and each ultrasonic transducer outputs the vibration frequency and amplitude independently.

[0028] A processing method of a matrix-type ultrasonic-assisted liquid-guided laser processing system includes the following steps:

[0029] 1) Clamp the workpiece to be processed on the workbench of the machine tool and lock it through the locking mechanism; turn on the machine tool and set the processing trajectory and processing parameters;

[0030] 2) Start the laser module, regulated high-pressure water module, CCD machine vision monitoring module, and ultrasonic vibration module through the host computer to ensure that the laser emits light normally, the pressure in the coupling water cavity is stable, the water jet is stable, the CCD camera takes pictures normally, and the ultrasonic vibration is stable;

[0031] 3) Adjust the laser parameters so that the laser output meets the processing requirements; adjust the high-pressure pump and overflow valve so that the pressure in the coupling water cavity meets the processing requirements and the water jet can be stably transmitted over a long distance.

[0032] 4) Use the CCD camera to monitor the position of the laser spot in real time, and the collected image data is processed and analyzed in the image processor of the host computer to obtain the light intensity values of each pixel point of the laser spot.

[0033] 5) Turn on the ultrasonic generator and controller, and set the initial output of the ultrasonic vibration; and adjust the laser module so that the focus of the laser spot coincides with the center of the nozzle, and process the workpiece on the vibration plate;

[0034] 6) The controller configures the frequencies and amplitudes of each ultrasonic transducer according to the processing trajectory and workpiece shape set in step 2), and adjusts the ultrasonic generator in real time according to the vibration signal transmitted back by the amplitude sensor;

[0035] 7) After the processing is completed, turn off the laser module, coupling water cavity module, regulated high-pressure water module, CCD machine vision monitoring module, and ultrasonic vibration module, turn off the machine tool, and remove the workpiece from the workbench; repeat steps 1) to 6) for the next processing.

[0036] The adjustment of the laser module to make the focus of the laser spot coincide with the center of the nozzle and process the workpiece on the vibration plate is specifically as follows:

[0037] 1-1) The laser emits a laser beam with a set wavelength according to the set laser parameters. The laser beam changes direction through a reflecting mirror and forms a laser spot focus through a focusing lens;

[0038] 1-2) Adjust the rotation angle of the reflecting mirror to change the position of the spot focus in the XY plane, and adjust the Z-direction displacement of the focusing lens (4) to adjust the Z-direction position of the spot focus;

[0039] 1-3) The laser beam enters the coupling water cavity through the window element, and by adjusting the Z-direction displacement of the focusing lens, the spot focus coincides with the center of the nozzle;

[0040] 1-4) The host computer pumps the water in the water tank into the coupling water cavity through the control of the high-pressure pump. The water in the coupling water cavity forms a high-pressure water jet through the nozzle, and the high-pressure water jet guides the laser to reach the workpiece surface to achieve material removal; at the same time, the host computer also adjusts the water pressure in the coupling water cavity in real time through the overflow valve.

[0041] The said steps 1 - 3) are specifically as follows:

[0042] Collect the images of the moving process of the laser spot focus in real time through a CCD camera, and process and analyze the collected images through the image processor in the upper computer to ensure that the laser spot focus coincides with the nozzle center;

[0043] Among them, the steps of processing and analyzing the collected images through the image processor in the upper computer and the CCD camera collecting and processing images are specifically as follows:

[0044] 2 - 1) Represent each pixel on the laser spot image data with a certain value from 0 to 255 according to the light intensity;

[0045] 2 - 2) Calculate the gradients of each point on the laser spot image, determine the position with the maximum gradient as the edge of the laser spot, and connect the points on the edge of the laser spot to form the laser spot contour;

[0046] 2 - 3) Calculate the position of the center of the laser spot according to the laser spot contour;

[0047] 2 - 4) Obtain the displacement vector of the laser spot according to the position of the center of the laser spot and the position of the nozzle center, and control the rotation angle of the reflector and the Z - direction displacement of the focusing lens to adjust the center of the laser spot to approach the nozzle center along the displacement vector;

[0048] 2 - 5) When the displacement vector is 0, the adjustment is completed.

[0049] The controller configures the frequencies and amplitudes of each ultrasonic transducer according to the processing trajectory and workpiece shape set in step 2), and adjusts the ultrasonic generator in real time according to the vibration signals transmitted back by the amplitude sensor. Specifically:

[0050] The controller configures the required frequencies and amplitudes of each ultrasonic transducer. The ultrasonic generator generates high - frequency alternating current signals and transmits them to the ultrasonic transducers. The ultrasonic transducers convert the electrical signals into mechanical vibrations and transmit the mechanical vibrations to the vibration plate; the workpiece forms ultrasonic vibrations along with the vibration plate;

[0051] The sound fields formed by each ultrasonic transducer are superimposed to form an interference sound field on the workpiece, enhancing the vibration in the processing area and weakening the vibration in other positions. The vibration signals of each point on the workpiece are transmitted to the controller through the amplitude sensor;

[0052] The controller adjusts the ultrasonic generator in real time according to the data fed back by the amplitude sensor;

[0053] The real - time adjustment of the ultrasonic generator includes the following steps:

[0054] 3 - 1) Detect the displacement of each test point on the workpiece through the amplitude sensor;

[0055] 3-2) Search for all the peak and valley values in the displacement data of a certain test point, calculate the average value of all the peak values and the average value of all the valley values and find the difference. Define half of the difference as the amplitude of this point;

[0056] 3-3) Subtract the actual amplitude obtained from the test from the optimal amplitude obtained from the theoretical calculation to get the difference between the actual amplitude and the optimal amplitude at each test point, which is defined as the amplitude deviation. When the amplitude deviation is within the set allowable range, continue the processing; when the amplitude deviation is outside the set allowable range, perform vibration optimization;

[0057] 3-4) Take the output frequency and amplitude of the ultrasonic generator as the input, and take the minimum amplitude deviation as the optimization goal to perform vibration optimization, and obtain the frequency and amplitude of each ultrasonic generator that minimize the amplitude deviation;

[0058] 3-5) Control the output of each ultrasonic generator to be updated to the optimal frequency and amplitude, and retest the displacement of each test point, and perform the iteration of steps 3-1) to 3-5) until the amplitude deviation is always within the set allowable range.

[0059] The present invention has the following beneficial effects and advantages:

[0060] 1. A matrix-type ultrasonic-assisted liquid-guided laser processing system and its processing method proposed by the present invention adopt an m×n matrix arrangement of ultrasonic transducers to form an interference sound field on the surface of the workpiece. Using an optimization algorithm, the frequency and amplitude of each ultrasonic transducer are adjusted in real time according to the change of the processing area position and the workpiece shape, so that the ultrasonic vibration in the processing area is strengthened and the vibration in other positions is weakened, which can effectively solve the problems of poor processing quality and reduced processing ability caused by the inability to discharge the processing products in time during the liquid-guided laser processing process.

[0061] 2. The present invention can reduce the influence of high-power ultrasonic vibration on the clamping stability of the workpiece, thereby realizing high-quality and high-efficiency processing of large-depth-diameter ratio micro-holes and surface micro-structures of large thin-walled workpieces. Description of the Drawings

[0062] Figure 1 is a schematic structural diagram of a matrix-type ultrasonic-assisted liquid-guided laser processing system proposed by the present invention;

[0063] Figure 2 is a schematic diagram of the arrangement of ultrasonic transducers;

[0064] Figure 3 is a schematic flow chart of a matrix-type ultrasonic-assisted liquid-guided laser processing method proposed by the present invention;

[0065] Among them, 1 is a CCD camera, 2 is a laser, 3 is a mirror, 4 is a focusing lens, 5 is an image processor, 6 is a window element, 7 is a coupling water cavity, 8 is a nozzle, 9 is an overflow valve, 10 is a high-pressure pump, 11 is a water tank, 12 is a water jet, 13 is a workpiece, 14 is a vibration plate, 15 is an ultrasonic transducer, 16 is an ultrasonic generator, 17 is a laser beam, 18 is a controller, and 19 is an amplitude sensor. Detailed implementation manner

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0067] As Figure 1 shown, it is a structural schematic diagram of the present invention. An embodiment of the present invention discloses a matrix ultrasonic-assisted liquid-guided laser processing system, including: a host computer and a laser module, a coupling water cavity module, an ultrasonic vibration module, a regulated high-pressure water module, and a CCD machine vision inspection and monitoring module connected thereto;

[0068] The laser module is used to receive the control instruction of the host computer, turn on and output a laser beam with a specific wavelength, and focus it into the coupling water cavity module;

[0069] The laser module includes: a laser 2, a mirror 3, and a focusing lens 4;

[0070] The laser 2 is horizontally fixed on the tooling and is connected to the host computer, receives the control instruction of the host computer to turn on, and emits a laser beam to the mirror 3;

[0071] The emission end of the laser 2 is coaxially arranged with the mirror 3; the included angle between the mirror 3 and the horizontal plane is: 0 degree to 90 degrees, so as to reflect the laser beam emitted by the laser 2 to the focusing lens 4 arranged directly below the mirror 3;

[0072] The mirror 3 is coaxially arranged with the focusing lens 4; the focusing lens 4 is arranged directly above the coupling water cavity module; by adjusting the rotation angle of the mirror 3, the position of the light spot focus in the XY plane is changed, and the Z-direction displacement of the focusing lens 4 is adjusted to realize the adjustment of the Z-direction position of the light spot focus.

[0073] The coupling water cavity module is arranged below the laser module, and is used to couple the incident laser beam with the water jet in the cavity, and form a high-pressure water jet to guide the laser to act on the surface of the workpiece 13;

[0074] The coupling water cavity module includes: a window element 6, a coupling water cavity 7, and a nozzle 8;

[0075] The window element 6 is arranged in the front of the CCD machine vision detection module and is coaxially arranged with the field of view axis of the CCD machine vision detection module; a reflector 3 and a focusing lens 4 are arranged between the window element 6 and the CCD machine vision detection module; when the laser beam enters the coupling water cavity 7 through the window element 6, the Z-direction displacement of the focusing lens 4 is controlled and adjusted by the host computer to make the spot focus coincide with the center of the nozzle 8; the water in the coupling water cavity 6 forms a high-pressure water jet through the nozzle 8, and the high-pressure water jet guides the laser to reach the surface of the workpiece 13 to achieve material removal.

[0076] The ultrasonic vibration module is arranged below the coupling water cavity module, used to fix the workpiece 13, and at the same time, form ultrasonic vibration on the workpiece 13;

[0077] The ultrasonic vibration module includes: a vibration plate 14, an ultrasonic transducer 15, an ultrasonic generator 16, a controller 18 and an amplitude sensor 19;

[0078] The vibration plate 14 is of a plate-like structure, and an ultrasonic transducer 15 is arranged below the vibration plate 14; the workpiece 13 is arranged on the vibration plate 14, and the vibration plate 14 is rigidly connected to the workpiece 13;

[0079] The controller 18 is connected to the ultrasonic transducer 15 through the ultrasonic generator 16, used to control the ultrasonic transducer 15 to generate ultrasonic vibration and transmit it to the vibration plate 14;

[0080] The ultrasonic generator 16 is used to generate high-frequency alternating current signals and transmit them to the ultrasonic transducer 15;

[0081] The amplitude sensor 19 is fixedly arranged above the workpiece 13 and is connected to the controller 18, used to collect the vibration signal on the workpiece 13 and feedback it to the controller 18; the controller 18 adjusts the ultrasonic generator 16 according to the real-time vibration signal;

[0082] The ultrasonic transducers 15 are arranged in an m×n matrix below the vibration plate 14, and each ultrasonic transducer 15 outputs the vibration frequency and amplitude independently.

[0083] The constant-pressure high-pressure water module is connected to the coupling water cavity module, used to supply water to the coupling water cavity module, and at the same time, adjust the water pressure of the coupling water cavity module;

[0084] The constant-pressure high-pressure water module includes: a water tank 11, a high-pressure pump 10, and an overflow valve 9;

[0085] The water tank 11 is connected to the coupling water cavity 7 through the high-pressure pump 10 and the overflow valve 9 arranged in parallel respectively;

[0086] The high-pressure pump 10 is used to pump the water tank 11 and transport it into the coupling water cavity;

[0087] The overflow valve 9 is used to adjust the water pressure in the coupling water cavity 7.

[0088] The CCD machine vision monitoring module is arranged above the laser module and is used to collect the position of the light spot focus of the laser beam and send it to the host computer. The host computer adjusts the laser module in real time according to the real-time position of the light spot focus and the position of the nozzle 8 of the coupling water cavity module to make the laser beam coincide with the nozzle 8 of the coupling water cavity module.

[0089] As Figure 3 shown, it is a schematic flow chart of a matrix ultrasonic-assisted liquid-guided laser processing method proposed by the present invention. The processing method of a matrix ultrasonic-assisted liquid-guided laser processing system of the present invention is characterized by including the following steps:

[0090] 1) Clamp the workpiece 13 to be processed on the workbench of the machine tool and lock it through the locking mechanism; turn on the machine tool and set the processing trajectory and processing parameters;

[0091] 2) Start the laser module, the regulated high-pressure water module, the CCD machine vision monitoring module and the ultrasonic vibration module through the host computer to ensure that the laser 2 emits light normally, the pressure of the coupling water cavity is stable, the water jet is stable, the CCD camera takes pictures normally, and the ultrasonic vibration is stable;

[0092] 3) Adjust the laser parameters to make the laser output meet the processing requirements; adjust the high-pressure pump and the overflow valve to make the pressure of the coupling water cavity meet the processing requirements so that the water jet can be stably transmitted over a long distance.

[0093] 4) Use the CCD camera 1 to monitor the position of the laser light spot in real time. The collected image data is processed and analyzed in the image processor 5 in the host computer to obtain the light intensity values of each pixel point of the laser light spot.

[0094] 5) Turn on the ultrasonic generator 16 and the controller 18, and set the initial output of the ultrasonic vibration; and adjust the laser module to make the light spot focus of the laser coincide with the center of the nozzle, and process the workpiece 13 on the vibration plate 14;

[0095] 6) The controller 18 configures the frequencies and amplitudes of the ultrasonic transducers 15 according to the processing trajectory and the shape of the workpiece set in step 2), and adjusts the ultrasonic generator 16 in real time according to the vibration signals transmitted back by the amplitude sensor 19;

[0096] The controller 18 configures the frequencies and amplitudes required by each ultrasonic transducer 15. The ultrasonic generator 16 generates a high-frequency alternating current signal and transmits it to the ultrasonic transducer 15. The ultrasonic transducer 15 converts the electrical signal into mechanical vibration and transmits the mechanical vibration to the vibration plate 14; the workpiece 13 forms ultrasonic vibration along with the vibration plate 14;

[0097] The sound fields formed by each ultrasonic transducer 15 are superimposed to form an interference sound field on the workpiece 13, enhancing the vibration in the machining area and weakening the vibration at other positions. The vibration signals of each point on the workpiece 13 are transmitted to the controller 18 through the amplitude sensor 19;

[0098] The controller 18 adjusts the ultrasonic generator 16 in real time according to the data fed back by the amplitude sensor 19;

[0099] The real-time adjustment of the ultrasonic generator 16 is specifically as follows:

[0100] a. Detect the displacement of each test point on the workpiece 13 through the amplitude sensor (19);

[0101] b. Find all the peaks and valleys in the displacement data of a certain test point, calculate the average value of all the peaks and the average value of all the valleys and take the difference, and define half of the difference as the amplitude of this point;

[0102] c. Subtract the actual amplitude obtained by testing from the optimal amplitude obtained by theoretical calculation to get the difference between the actual amplitude and the optimal amplitude of each test point, which is defined as the amplitude deviation. When the amplitude deviation is within the set allowable range, continue the machining; when the amplitude deviation is outside the set allowable range, perform vibration optimization;

[0103] d. Take the output frequency and amplitude of the ultrasonic generator (16) as the input, and take the minimum amplitude deviation as the optimization goal to perform vibration optimization, and obtain the frequency and amplitude of each ultrasonic generator (16) that minimize the amplitude deviation;

[0104] e. Control the output of each ultrasonic generator (16) to be updated to the optimal frequency and amplitude, and retest the displacement of each test point, and perform the iteration of steps a to e until the amplitude deviation is always within the set allowable range.

[0105] 7) After the machining is completed, turn off the laser module, the coupling water chamber module, the regulated high-pressure water module, the CCD machine vision inspection and monitoring module, and the ultrasonic vibration module, turn off the machine tool, and remove the workpiece from the workbench; repeat steps 1) to 6) for the next machining.

[0106] The adjustment of the laser module to make the laser spot focus coincide with the nozzle center and machine the workpiece 13 on the vibration plate 14 is specifically as follows:

[0107] 1-1) The laser 2 outputs a laser beam with a set wavelength according to the set laser parameters. The laser beam is redirected through the reflecting mirror and forms a laser spot focus through the focusing lens;

[0108] 1-2) Adjust the rotation angle of the reflecting mirror 3 to change the position of the spot focus in the XY plane, and adjust the Z-direction displacement of the focusing lens 4 to adjust the Z-direction position of the spot focus;

[0109] 1-3) The laser beam enters the coupling water chamber 7 through the window element 6. By adjusting the Z-direction displacement of the focusing lens 4, the spot focus is made to coincide with the center of the nozzle 8;

[0110] 1-4) The host computer pumps the water in the water tank 11 into the coupling water chamber 7 by controlling the high-pressure pump 10. The water in the coupling water chamber 7 forms a high-pressure water jet 12 through the nozzle 8, and the high-pressure water jet 12 guides the laser to reach the surface of the workpiece 13 to achieve material removal; meanwhile, the host computer also adjusts the water pressure in the coupling water chamber 7 in real time through the overflow valve 9.

[0111] Among them, step 1-3) is specifically:

[0112] The image of the moving process of the spot focus is collected in real time by the CCD camera 1, and the collected image is processed and analyzed by the image processor 5 in the host computer to ensure that the spot focus coincides with the center of the nozzle 8;

[0113] Among them, the step of the CCD camera collecting and processing the image by the image processor 5 in the host computer is specifically:

[0114] 2-1) According to the light intensity, each pixel on the laser spot image data is represented by a certain value from 0 to 255;

[0115] 2-2) Calculate the gradients of each point on the laser spot image, determine the position with the maximum gradient as the spot edge, and connect the points on the spot edge to form a spot contour;

[0116] 2-3) Calculate the position of the spot center according to the spot contour;

[0117] 2-4) According to the position of the spot center and the position of the nozzle center, obtain the displacement vector of the laser spot, and control the rotation angle of the mirror 3 and the Z-direction displacement of the focusing lens 4 to adjust the spot center to approach the nozzle center along the displacement vector;

[0118] 2-5) When the displacement vector is 0, the adjustment is completed.

[0119] Example 1:

[0120] In this embodiment, first, the laser 2 outputs a laser beam 17 with a specific wavelength. The laser beam 17 is redirected by the mirror 3 and forms a spot focus of the laser through the focusing lens 4. Both the mirror 3 and the focusing lens 4 are installed on a precision rotary positioning mechanism. By adjusting the rotation angle of the mirror 3 through the precision rotary positioning mechanism, the position of the spot focus in the XY plane is changed, and by adjusting the Z-direction displacement of the focusing lens 4, the Z-direction position of the spot focus is adjusted. The laser beam 17 enters the coupling water chamber 7 through the window element 6. By adjusting the Z-direction displacement of the focusing lens 4, the spot focus is made to coincide with the center 8 of the nozzle. The water in the coupling water chamber 7 forms a high-pressure water jet 12 through the nozzle 8, and the high-pressure water jet 12 guides the laser to reach the surface of the workpiece 13 to achieve material removal.

[0121] The water in the water tank 11 is transmitted to the coupling water chamber 7 through the high-pressure pump 10, and the water pressure in the coupling water chamber 7 is adjusted through the overflow valve 9. The image of the moving process of the spot focus is collected in real time by the CCD camera 1, and the collected image is processed and analyzed by the image processor 5 in the upper computer to ensure that the spot focus coincides with the center of the nozzle 8.

[0122] The controller 18 configures the required frequencies and amplitudes of each ultrasonic transducer 15. The ultrasonic generator 16 generates a high-frequency alternating current signal and transmits it to the ultrasonic transducer 15. The ultrasonic transducer 15 converts the electrical signal into mechanical vibration and transmits the mechanical vibration to the vibration plate 14; the workpiece 13 is rigidly connected to the vibration plate 14 and forms ultrasonic vibration along with the vibration plate 14.

[0123] As Figure 2 shown, in this embodiment, the ultrasonic transducers 15 are arranged in a 4×5 matrix below the vibration plate. The sound fields formed by each ultrasonic transducer are superimposed to form an interference sound field on the workpiece, enhancing the vibration in the processing area and weakening the vibration in other positions. The vibration signals of each point on the workpiece are transmitted to the controller 18 through the amplitude sensor 19 to form a closed-loop control. The energy of the ultrasonic vibration is transmitted to the processing area, which will prompt the processing product to be quickly separated from the substrate, and the processing product is quickly discharged from the processing area under the flushing action of the water jet 12; at the same time, since the vibration in other positions is suppressed, the influence of the vibration on the clamping stability can be reduced.

[0124] Embodiment 2:

[0125] The present invention also discloses a matrix-type ultrasonic vibration-assisted liquid-guided laser processing system and its processing method, which can realize high-quality and high-efficiency processing of large deep-diameter ratio micro-holes and surface microstructures on large thin-walled workpieces. As Figure 3 shown, it includes the following steps:

[0126] 1) Clamp the workpiece to be processed on the workbench of the machine tool and lock it through the locking mechanism.

[0127] 2) Turn on the machine tool and set the processing trajectory and processing parameters.

[0128] 3) Turn on the laser module, and couple the water chamber module, the regulated high-pressure water module, the CCD machine vision monitoring module, and the ultrasonic vibration module.

[0129] 4) Select a green laser for the laser, with an output laser wavelength of 532 nm and a repetition frequency of 400 kHz.

[0130] 5) Adjust the high-pressure pump and the overflow valve to make the water pressure in the coupled water chamber stable at 10 MPa.

[0131] 6) Set the initial output frequency of the ultrasonic vibration to 100 kHz and the initial amplitude to 5 μm.

[0132] 7) Use the CCD camera to monitor the position of the laser spot, and the collected image data is processed and analyzed in the image processor.

[0133] 8) Adjust the rotation angle and position of the mirror, and the Z-direction distance between the focusing lens and the window element, so that the spot focus of the laser coincides with the nozzle center.

[0134] 9) Perform ultrasonic-assisted liquid-guided laser machining on the workpiece according to the machining trajectory and machining parameters set in step 2. The feed process controller automatically adjusts the frequency and amplitude of the ultrasonic transducer according to the machining trajectory and the shape of the workpiece.

[0135] 10) After the machining is completed, turn off the laser module, the coupled water chamber module, the regulated high-pressure water module, the CCD machine vision monitoring module, and the ultrasonic vibration module, turn off the machine tool, and remove the workpiece from the workbench.

[0136] A matrix ultrasonic-assisted liquid-guided laser machining system and its machining method proposed by the present invention adopt an m×n matrix arrangement of ultrasonic transducers to form an interference sound field on the surface of the workpiece. Using an optimization algorithm, the frequency and amplitude of each ultrasonic transducer are adjusted in real time according to the change of the machining area position and the shape of the workpiece, so that the ultrasonic vibration in the machining area is enhanced and the vibration in other positions is weakened, which can effectively solve the problems of poor machining quality and reduced machining ability caused by the inability to discharge the machining products in time during the liquid-guided laser machining process. At the same time, it can also reduce the influence of high-power ultrasonic vibration on the clamping stability of the workpiece, so as to achieve high-quality and high-efficiency machining of large deep-diameter ratio micro-holes and surface micro-structures on large thin-walled workpieces.

[0137] The above is only the embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, extension, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A matrix ultrasonic-assisted liquid-guided laser processing system, characterized in that, Including: a host computer and a laser module, a coupling water cavity module, an ultrasonic vibration module, a regulated high-pressure water module, and a CCD machine vision detection module connected thereto; The laser module is configured to receive control instructions from the host computer, turn on and output a laser beam of a specific wavelength, and focus it into the coupling water cavity module; The coupling water cavity module is disposed below the laser module and is configured to couple the incident laser beam with the water jet in the cavity and form a high-pressure water jet to guide the laser to act on the surface of the workpiece (13); The ultrasonic vibration module is disposed below the coupling water cavity module and is configured to fix the workpiece (13) and simultaneously form ultrasonic vibration on the workpiece (13); The regulated high-pressure water module is connected to the coupling water cavity module and is configured to supply water to the coupling water cavity module and, at the same time, adjust the water pressure of the coupling water cavity module; The CCD machine vision detection module is disposed above the laser module and is configured to collect the position of the light spot focus of the laser beam and send it to the host computer. The host computer adjusts the laser module in real time according to the real-time position of the light spot focus and the position of the nozzle (8) of the coupling water cavity module to achieve the coincidence of the laser beam and the nozzle (8) of the coupling water cavity module.

2. The matrix ultrasonic-assisted liquid-guided laser processing system according to claim 1, characterized in that, The laser module includes: a laser (2), a reflecting mirror (3), and a focusing lens (4); The laser (2) is horizontally fixed on the tooling and is connected to the host computer, receives the control instruction to turn on, and emits a laser beam to the reflecting mirror (3); The emitting end of the laser (2) is coaxially arranged with the reflecting mirror (3); the included angle between the reflecting mirror (3) and the horizontal plane is: 0 degree to 90 degrees to reflect the laser beam emitted by the laser (2) onto the focusing lens (4) disposed directly below the reflecting mirror (3); The reflecting mirror (3) is coaxially arranged with the focusing lens (4); the focusing lens (4) is disposed directly above the coupling water cavity module; by adjusting the rotation angle of the reflecting mirror (3), the position of the light spot focus in the XY plane is changed, and the Z-direction displacement of the focusing lens (4) is adjusted to achieve the adjustment of the Z-direction position of the light spot focus.

3. The matrix ultrasonic-assisted liquid-guided laser processing system according to claim 1, characterized in that, The coupling water cavity module includes: a window element (6), a coupling water cavity (7), and a nozzle (8); The window element (6) is disposed directly in front of the CCD machine vision detection module and is coaxially arranged with the field axis of the CCD machine vision detection module; a reflecting mirror (3) and a focusing lens (4) are provided between the window element (6) and the CCD machine vision detection module; when the laser beam enters the coupling water cavity (7) through the window element (6), the Z-direction displacement of the focusing lens (4) is controlled and adjusted by the host computer to make the light spot focus coincide with the center of the nozzle (8); the water in the coupling water cavity (6) forms a high-pressure water jet through the nozzle (8), and the high-pressure water jet guides the laser to reach the surface of the workpiece (13) to achieve material removal.

4. The matrix ultrasonic-assisted liquid-guided laser processing system according to claim 1, characterized in that, The regulated high-pressure water module includes: a water tank (11), a high-pressure pump (10), and an overflow valve (9); The water tank (11) is connected to the coupling water cavity (7) respectively through the high-pressure pump (10) and the overflow valve (9) arranged in parallel; The high-pressure pump (10) is configured to pump the water tank (11) and transport it into the coupling water cavity; The overflow valve (9) is used to regulate the water pressure in the coupling water chamber (7).

5. The matrix ultrasonic-assisted liquid-guided laser processing system according to claim 1, characterized in that, The ultrasonic vibration module includes: a vibration plate (14), an ultrasonic transducer (15), an ultrasonic generator (16), a controller (18), and an amplitude sensor (19); The vibration plate (14) has a plate-like structure, and an ultrasonic transducer (15) is provided below the vibration plate (14); a workpiece (13) is provided on the vibration plate (14), and the vibration plate (14) is rigidly connected to the workpiece (13); The controller (18) is connected to the ultrasonic transducer (15) through the ultrasonic generator (16), and is used to control the ultrasonic transducer (15) to generate ultrasonic vibrations and transmit them to the vibration plate (14); The ultrasonic generator (16) is used to generate high-frequency alternating current signals and transmit them to the ultrasonic transducer (15); The amplitude sensor (19) is fixedly arranged above the workpiece (13) and is connected to the controller (18), and is used to collect the vibration signals on the workpiece (13) and feedback them to the controller (18); the controller (18) adjusts the ultrasonic generator (16) according to the real-time vibration signals; The ultrasonic transducers (15) are arranged in an m×n matrix below the vibration plate (14), and each ultrasonic transducer (15) outputs the vibration frequency and amplitude independently.

6. The processing method of the matrix ultrasonic-assisted liquid-guided laser processing system according to claim 1, characterized in that, It includes the following steps: 1) Clamp the workpiece (13) to be processed on the workbench of the machine tool and lock it through the locking mechanism; start the machine tool and set the machining trajectory and machining parameters; 2) Start the laser module, the regulated high-pressure water module, the CCD machine vision detection module, and the ultrasonic vibration module through the upper computer to ensure that the laser (2) emits light normally, the pressure in the coupling water chamber is stable, the water jet is stable, the CCD camera takes pictures normally, and the ultrasonic vibration is stable; 3) Adjust the laser parameters so that the laser output meets the machining requirements; adjust the high-pressure pump and the overflow valve so that the pressure in the coupling water chamber meets the machining requirements and the water jet can be stably transmitted over a long distance. 4) Use the CCD camera (1) to monitor the position of the laser spot in real time, and the collected image data is processed and analyzed in the image processor (5) of the upper computer to obtain the light intensity values of each pixel point of the laser spot. 5) Turn on the ultrasonic generator (16) and the controller (18), and set the initial output of the ultrasonic vibration; and adjust the laser module so that the focal point of the laser spot coincides with the center of the nozzle, and machine the workpiece (13) on the vibration plate (14); 6) The controller (18) configures the frequencies and amplitudes of the ultrasonic transducers (15) according to the machining trajectory and the shape of the workpiece set in step 2), and adjusts the ultrasonic generator (16) in real time according to the vibration signals transmitted back by the amplitude sensor (19); 7) After the machining is completed, turn off the laser module, the coupling water chamber module, the regulated high-pressure water module, the CCD machine vision detection module, and the ultrasonic vibration module, turn off the machine tool, and remove the workpiece from the workbench; repeat steps 1) to 6) for the next machining.

7. The processing method of a matrix ultrasonic-assisted liquid-guided laser processing system according to claim 6, characterized in that, The adjustment of the laser module to make the focal point of the laser spot coincide with the center of the nozzle and machine the workpiece (13) on the vibration plate (14) is specifically: 1-1) The laser (2) outputs a laser beam with a set wavelength according to the set laser parameters. The laser beam is redirected by a reflecting mirror and forms a laser spot focus through a focusing lens. 1-2) Adjust the rotation angle of the reflecting mirror (3) to change the position of the spot focus in the XY plane, and adjust the Z-direction displacement of the focusing lens (4) to adjust the Z-direction position of the spot focus. 1-3) The laser beam enters the coupling water chamber (7) through the window element (6). By adjusting the Z-direction displacement of the focusing lens (4), the spot focus is made to coincide with the center of the nozzle (8). 1-4) The host computer controls the high-pressure pump (10) to extract water from the water tank (11) into the coupling water chamber (7). The water in the coupling water chamber (7) forms a high-pressure water jet (12) through the nozzle (8). The high-pressure water jet (12) guides the laser to reach the surface of the workpiece (13) to achieve material removal. At the same time, the host computer also adjusts the water pressure in the coupling water chamber (7) in real time through the overflow valve (9).

8. The processing method of a matrix ultrasonic-assisted liquid-guided laser processing system according to claim 7, characterized in that, In step 1-3) above, specifically: The CCD camera (1) collects images of the moving process of the spot focus in real time, and the image processor (5) in the host computer processes and analyzes the collected images to ensure that the spot focus coincides with the center of the nozzle (8). Among them, the steps of the CCD camera collecting and processing images by the image processor (5) in the host computer are specifically as follows: 2-1) According to the light intensity, each pixel on the laser spot image data is represented by a certain value from 0 to 255. 2-2) Calculate the gradients of each point on the laser spot image, determine the position with the maximum gradient as the spot edge, and connect the points on the spot edge to form a spot contour. 2-3) Calculate the center position of the spot according to the spot contour. 2-4) According to the center position of the spot and the center position of the nozzle, obtain the displacement vector of the laser spot, and control the rotation angle of the reflecting mirror (3) and the Z-direction displacement of the focusing lens (4) to adjust the center of the spot to approach the center of the nozzle along the displacement vector. 2-5) When the displacement vector is 0, the adjustment is completed.

9. The processing method of a matrix ultrasonic-assisted liquid-guided laser processing system according to claim 8, characterized in that, The controller (18) configures the frequencies and amplitudes of each ultrasonic transducer (15) according to the processing trajectory and workpiece shape set in step 2), and adjusts the ultrasonic generator (16) in real time according to the vibration signals transmitted back by the amplitude sensor (19). Specifically: The controller (18) configures the required frequencies and amplitudes of each ultrasonic transducer (15). The ultrasonic generator (16) generates a high-frequency alternating current signal and transmits it to the ultrasonic transducer (15). The ultrasonic transducer (15) converts the electrical signal into mechanical vibration and transmits the mechanical vibration to the vibration plate (14). The workpiece (13) forms ultrasonic vibration along with the vibration plate (14). The sound fields formed by each ultrasonic transducer (15) are superimposed to form an interference sound field on the workpiece (13), enhancing the vibration in the processing area and weakening the vibration in other positions. The vibration signals of each point on the workpiece (13) are transmitted to the controller (18) through the amplitude sensor (19). The controller (18) adjusts the ultrasonic generator (16) in real time according to the data fed back by the amplitude sensor (19).

10. The processing method of a matrix ultrasonic-assisted liquid-guided laser processing system according to claim 9, characterized in that, The real-time adjustable ultrasonic generator (16) includes the following steps: 3-1) Detect the displacement of each test point on the workpiece (13) through the amplitude sensor (19); 3-2) Find all the peaks and valleys in the displacement data of a certain test point, calculate the average value of all peaks and the average value of all valleys and take the difference, and define half of the difference as the amplitude of this point; 3-3) Subtract the actual amplitude obtained by testing from the optimal amplitude obtained by theoretical calculation to get the difference between the actual amplitude and the optimal amplitude of each test point, which is defined as the amplitude deviation. When the amplitude deviation is within the set allowable range, continue the processing; when the amplitude deviation is outside the set allowable range, perform vibration optimization; 3-4) Take the output frequency and amplitude of the ultrasonic generator (16) as inputs, and take the minimum amplitude deviation as the optimization goal to perform vibration optimization to obtain the frequency and amplitude of each ultrasonic generator (16) that minimize the amplitude deviation; 3-5) Control the output of each ultrasonic generator (16) to be updated to the optimal frequency and amplitude, and retest the displacement of each test point, and perform iterations of steps 3-1) to 3-5) until the amplitude deviation is always within the set allowable range.

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