A matrix ultrasonic-assisted liquid-guided laser processing system and method

Abstract

The application belongs to the technical field of laser processing, and particularly relates to a matrix type ultrasonic auxiliary liquid guide laser processing system and method, which comprises the following steps: a laser module receives a control instruction of an upper computer, outputs a laser beam, and focuses into a coupling water cavity module; the coupling water cavity module couples the 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; an ultrasonic vibration module is used for forming ultrasonic vibration on the workpiece; a stable high-pressure water module supplies water for the coupling water cavity module; a CCD machine vision inspection and monitoring module collects the position of a laser beam spot focus point 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 laser beam spot focus point and the nozzle position of the coupling water cavity module. The application can reduce the influence of high-power ultrasonic vibration on the clamping stability of the workpiece, so as to realize high-quality and high-efficiency processing of large thin-walled workpieces, large depth-diameter ratio micro-holes and surface micro-structures.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser processing, in particular to a matrix type ultrasonic auxiliary liquid-guided laser processing system and method. BACKGROUND

[0002] Liquid-guided laser processing is a technology that combines laser processing and water jet processing to achieve micro processing. The water jet guides the laser transmission to the workpiece surface, thereby achieving workpiece processing. Compared with traditional laser processing, liquid-guided laser processing technology has the advantages of low thermal damage, long working distance, and high processing precision. It has certain advantages for difficult-to-machine materials (such as hard and brittle materials, composite materials, etc.) and large-depth-to-diameter ratio micro holes and surface micro structure machining. In the process of liquid-guided laser processing, the material absorbs laser energy and vaporizes or melts and leaves the substrate to form material removal. As the processing depth increases, the chip removal condition becomes poor, and the processing products cannot be removed in time, which on the one hand will splash or deposit on the processing surface to form a recast layer, reducing the processing quality; on the other hand, it will form a barrier, hindering the further transmission of the laser, reducing the processing capacity.

[0003] Ultrasonic vibration technology transmits high-frequency mechanical oscillation to the processing area through an ultrasonic generator to emit a high-frequency oscillation signal and a transducer, which can promote the separation of the processing product from the substrate and accelerate the removal of the processing product, thereby improving the processing surface quality. There are two ways to use ultrasonic vibration technology for auxiliary processing. One is to use water or oil as a medium to transmit the mechanical vibration generated by the ultrasonic transducer to the workpiece. However, this transmission method inevitably consumes a large amount of vibration energy in the medium, resulting in insufficient energy transmitted to the workpiece to separate the processing product from the substrate. The other is to rigidly connect the ultrasonic transducer to the workpiece, which can directly transmit the mechanical vibration generated by the ultrasonic transducer to the workpiece, reducing energy loss. However, when processing large-size workpieces, especially large-thin-wall workpieces, the vibration at each point on the workpiece is uneven, and it is difficult to ensure the vibration amplitude and 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 auxiliary processing, which affects the clamping stability of the workpiece.

[0004] At present, there is no effective method to solve the technical problems that the processing products cannot be removed in time in the process of liquid-guided laser processing, and the ultrasonic vibration cannot be effectively transmitted to the processing area. SUMMARY

[0005] The purpose of the present application is to provide a matrix type ultrasonic auxiliary liquid-guided laser processing system and method to overcome the technical problem that ultrasonic vibration cannot be effectively transmitted to the processing area.

[0006] The technical scheme adopted by the present application to achieve the above-mentioned purpose is as follows: a matrix type ultrasonic auxiliary liquid guide laser processing system, comprising: an upper computer and a laser module, a coupling water cavity module, an ultrasonic vibration module, a stable high-pressure water module and a CCD machine vision inspection and monitoring module connected with the upper computer;

[0007] The laser module is used for receiving the control instruction of the upper computer, and opening the laser beam of a specific wavelength and focusing into the coupling water cavity module;

[0008] The coupling water cavity module is arranged below the laser module, and is used for coupling the incident laser beam with the water jet in the cavity, and forming a high-pressure water jet to guide the laser to act on the workpiece surface;

[0009] The ultrasonic vibration module is arranged below the coupling water cavity module, and is used for fixing the workpiece, and forming ultrasonic vibration on the workpiece;

[0010] The stable high-pressure water module is connected with the coupling water cavity module, and is used for supplying water for the coupling water cavity module, and adjusting the water pressure of the coupling water cavity module;

[0011] The CCD machine vision inspection and monitoring module is arranged above the laser module, and is used for collecting the position of the focal point of the laser beam and sending to the upper computer, and the upper computer adjusts the laser module in real time according to the real-time position of the focal point and the nozzle position of the coupling water cavity module, so as to realize the coincidence of the laser beam and the nozzle of the coupling water cavity module.

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

[0013] The laser is horizontally fixed on the tool, and is connected with the upper computer, receives the control instruction of the upper computer, and emits the laser beam to the mirror;

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

[0015] The mirror is coaxially arranged with the focusing lens; the focusing lens is arranged directly above the coupling water cavity module; the position of the focal point XY plane is changed by adjusting the rotation angle of the mirror, and the Z direction displacement of the focusing lens is adjusted, so as to adjust the Z direction position of the focal point.

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

[0017] The window element is arranged in the forward direction of the CCD machine vision inspection module and coaxially arranged with the field axis of the CCD machine vision inspection module; a mirror 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 upper computer to make the focal point of the light spot coincide with the center of the nozzle; the water in the coupling water cavity forms a high-pressure water jet through the nozzle, the high-pressure water jet guides the laser to reach the workpiece surface, and material removal is realized.

[0018] The stable high-pressure water module comprises a water tank, a high-pressure pump and an overflow valve.

[0019] The water tank is connected with the coupling water cavity through the parallelly arranged high-pressure pump and overflow valve.

[0020] The high-pressure pump is used to extract the water tank and deliver water 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 comprises a vibration plate, an ultrasonic transducer, an ultrasonic generator, a controller and an amplitude sensor.

[0023] The vibration plate is in a plate structure, and the ultrasonic transducer is arranged below the vibration plate; the workpiece is arranged on the vibration plate, and the vibration plate is rigidly connected with the workpiece.

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

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

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

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

[0028] A processing method of a matrix ultrasonic auxiliary liquid-guided laser processing system, comprising the following steps:

[0029] 1) Clamping the workpiece to be processed on the workbench of the machine tool through the locking mechanism; turning on the machine tool and setting the processing track and processing parameters;

[0030] 2) Start the laser module, the stable high-pressure water module, the CCD machine vision inspection module and the ultrasonic vibration module by the host computer to ensure that the laser emits normally, the coupling water cavity pressure 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 to make the laser output meet the processing requirements; adjust the high-pressure pump and the overflow valve to make the coupling water cavity pressure meet the processing requirements, so that the water jet can be transmitted stably for a long distance.

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

[0033] 5) Turn on the ultrasonic generator and the controller, set the initial output of the ultrasonic vibration, adjust the laser module to make the focal point of the laser spot coincide with the center of the nozzle, and process the workpiece on the vibration plate;

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

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

[0036] The laser module is adjusted to make the focal point of the laser spot coincide with the center of the nozzle, and the workpiece on the vibration plate is processed, specifically:

[0037] 1-1) The laser outputs a laser beam of a set wavelength according to the set laser parameters, the laser beam changes direction through the reflecting mirror, and the focal point of the laser spot is formed through the focusing lens;

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

[0039] 1-3) The laser beam enters the coupling water cavity through the window element, and the Z-direction displacement of the focusing lens is adjusted to make the focal point of the laser spot coincide with the center of the nozzle;

[0040] 1-4) The host computer draws water in the water tank into the coupling water cavity through the high-pressure pump, the water in the coupling water cavity forms a high-pressure water jet through the nozzle, the high-pressure water jet guides the laser to the surface of the workpiece to realize 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 steps 1-3) are specifically:

[0042] The movement process of the light spot focus is collected by a CCD camera in real time, and the collected images are processed and analyzed by an image processor in the host computer to ensure that the light spot focus coincides with the nozzle center;

[0043] The processing and analysis of the collected images by the image processor in the host computer, the CCD camera image processing step, are specifically:

[0044] 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;

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

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

[0047] 2-4) According to the spot center position and the nozzle center position, the displacement vector of the laser spot is obtained, the rotation angle of the reflector and the Z direction displacement of the focusing lens are adjusted to adjust the spot center to move along the displacement vector to the nozzle center;

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

[0049] The controller configures the frequency and amplitude of each ultrasonic transducer according to the machining trajectory and workpiece shape set in step 2), and adjusts the ultrasonic wave generator in real time according to the vibration signal returned by the amplitude sensor, specifically:

[0050] The controller configures the frequency and amplitude required by each ultrasonic transducer, and the ultrasonic wave generator generates a high-frequency alternating current signal to transmit to the ultrasonic transducer, which converts the electrical signal into mechanical vibration and transmits the mechanical vibration to the vibration plate; the workpiece forms ultrasonic vibration with the vibration plate;

[0051] The sound field formed by each ultrasonic transducer is superimposed to form an interference sound field on the workpiece, which enhances the vibration of the machining area and weakens the vibration of other positions; the vibration signal of each point on the workpiece is transmitted to the controller through the amplitude sensor;

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

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

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

[0055] 3-2) Find all peak values and valley values in the displacement data of a test point, calculate the average value of all peak values and the average value of all valley values and make a difference, and define the 1 / 2 of the difference value as the amplitude of the point;

[0056] 3-3) The difference between the actual amplitude obtained by the test and the optimal amplitude calculated by the theory is the amplitude deviation, and when the amplitude deviation is within the set allowable range, the processing is continued; when the amplitude deviation is outside the set allowable range, the vibration optimization is performed;

[0057] 3-4) The output frequency and amplitude of the ultrasonic generator are input, and the minimum amplitude deviation is the optimization target, and the vibration optimization is performed to obtain the minimum amplitude deviation of the frequency and amplitude of each ultrasonic generator;

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

[0059] The present application has the following advantages and benefits:

[0060] 1. The matrix ultrasonic auxiliary liquid guide laser processing system and the processing method thereof provided by the present application adopt an m*n matrix ultrasonic transducer arrangement mode to form an interference sound field on the surface of a workpiece, and use an optimization algorithm to adjust the frequency and amplitude of each ultrasonic transducer in real time according to the change of the processing area position and the shape of the workpiece, so that the ultrasonic vibration of the processing area is strengthened and the vibration of the remaining positions is weakened, which can effectively solve the problem of poor processing quality and reduced processing capacity caused by the failure of the processing products to be discharged in time during the liquid guide laser processing,

[0061] 2. The present application can reduce the impact of high-power ultrasonic vibration on the stability of the workpiece clamping, thereby realizing high-quality and efficient processing of large-thin-wall workpieces with large depth-diameter ratio micro-holes and surface micro-structures. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 is a structural schematic diagram of a matrix ultrasonic auxiliary liquid guide laser processing system provided by the present application;

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

[0064] Figure 3 is a flowchart of a matrix ultrasonic auxiliary liquid guide laser processing method provided by the present application;

[0065] Among them, 1 is a CCD camera, 2 is a laser, 3 is a reflector, 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 vibrating 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

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, but not all embodiments.

[0067] like Figure 1 The diagram shown is a structural schematic 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 stabilizing high-pressure water module, and a CCD machine vision inspection and monitoring module connected thereto.

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

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

[0070] The laser 2 is horizontally fixed on the fixture and connected to the host computer. It receives the control command from the host computer to turn on and emits a laser beam to the reflector 3.

[0071] The emitting end of the laser 2 is coaxially arranged with the reflector 3; the angle between the reflector 3 and the horizontal plane is 0 degrees to 90 degrees, so as to reflect the laser beam emitted by the laser 2 onto the focusing lens 4 located directly below the reflector 3.

[0072] The reflector 3 and the focusing lens 4 are coaxially arranged; the focusing lens 4 is located directly above the coupling water cavity module; by adjusting the rotation angle of the reflector 3, the position of the light spot focal point 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 focal point.

[0073] The coupling water cavity module is located 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: window element 6, coupling water cavity 7, and nozzle 8;

[0075] The window element 6 is arranged in the forward direction of the CCD machine vision inspection module and coaxially arranged with the field axis of the CCD machine vision inspection module; the window element 6 and the CCD machine vision inspection module are provided with a reflector 3 and a focusing lens 4; 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 upper computer, so that the focal point of the light spot is coincided 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, the high-pressure water jet guides the laser to reach the surface of the workpiece 13, and material removal is realized.

[0076] The ultrasonic vibration module is arranged below the coupling water cavity module, is used for fixing the workpiece 13, and simultaneously forms ultrasonic vibration on the workpiece 13;

[0077] The ultrasonic vibration module comprises 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 a plate structure, and the 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 with the workpiece 13;

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

[0080] The ultrasonic generator 16 is used for generating a high-frequency alternating current signal and transmitting the high-frequency alternating current signal to the ultrasonic transducer 15;

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

[0082] The ultrasonic transducer 15 is arranged below the vibration plate 14 in an m*n matrix mode, and each ultrasonic transducer 15 separately outputs a vibration frequency and amplitude.

[0083] The stable high-pressure water module is connected with the coupling water cavity module, is used for supplying water for the coupling water cavity module, and simultaneously adjusts the water pressure of the coupling water cavity module;

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

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

[0086] The high-pressure pump 10 is used for pumping the water tank 11 and delivering the water tank 11 into the coupling water cavity;

[0087] The overflow valve 9 is used for adjusting 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 for collecting the position of the focal point of the laser spot and sending to the upper computer, and the upper computer adjusts the laser module in real time according to the real-time position of the focal point of the laser spot and the position of the nozzle 8 of the coupling water cavity module, so as to realize the coincidence of the laser beam and the nozzle 8 of the coupling water cavity module.

[0089] As shown in Figure 3 Fig. 1 is a flowchart of a matrix ultrasonic auxiliary liquid-guided laser processing method according to the present application, and the processing method of a matrix ultrasonic auxiliary liquid-guided laser processing system according to the present application, and the processing method comprises the following steps:

[0090] 1) clamping the workpiece 13 to be processed on the workbench of the machine tool through the locking mechanism; starting the machine tool, and setting the processing track and processing parameters;

[0091] 2) starting the laser module, the stable high-pressure water module, the CCD machine vision monitoring module and the ultrasonic vibration module through the upper computer, so as to ensure that the laser 2 normally emits light, the coupling water cavity pressure is stable, the water jet is stable, the CCD camera is normal, and the ultrasonic vibration is stable;

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

[0093] 4) monitoring the position of the laser spot in real time by using the CCD camera 1, processing and analyzing the collected image data in the image processor 5 in the upper computer, and obtaining the numerical value of the light intensity of each pixel point of the laser spot.

[0094] 5) starting the ultrasonic generator 16 and the controller 18, setting the initial output of the ultrasonic vibration, adjusting the laser module to make the focal point of the laser spot coincide with the center of the nozzle, and processing the workpiece 13 on the vibration plate 14;

[0095] 6) the controller 18 configures the frequency and amplitude of each ultrasonic transducer 15 according to the processing track and the shape of the workpiece set in step 2), and adjusts the ultrasonic generator 16 in real time according to the vibration signal returned by the amplitude sensor 19;

[0096] The controller 18 configures the frequency and amplitude 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 with the vibration plate 14;

[0097] Each ultrasonic transducer 15 forms a sound field which, after superposition, forms an interference sound field on the workpiece 13, enhancing the vibration of the machining area and weakening the vibration of other positions. The vibration signals of each point of the workpiece 13 are transmitted to the controller 18 through the amplitude sensor 19;

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

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

[0100] a. The displacement of each test point on the workpiece 13 is detected by the amplitude sensor 19;

[0101] b. All peak values and valley values in the displacement data of a test point are found, the average value of all peak values and the average value of all valley values are calculated and the difference is selected, and the 1 / 2 of the difference is defined as the amplitude of the point;

[0102] c. The difference between the actual amplitude obtained by testing and the optimal amplitude obtained by theoretical calculation is defined as the amplitude deviation, and when the amplitude deviation is within the set allowable range, the machining is continued; when the amplitude deviation is outside the set allowable range, the vibration is optimized;

[0103] d. The output frequency and amplitude of the ultrasonic wave generator 16 are taken as inputs, and the minimum amplitude deviation is taken as the optimization target to optimize the vibration, so as to obtain the frequency and amplitude of each ultrasonic wave generator 16 that minimizes the amplitude deviation;

[0104] e. The output of each ultrasonic wave generator 16 is updated to the optimal frequency and amplitude, and the displacement of each test point is retested, and steps a-e are iterated until the amplitude deviation is always within the set allowable range.

[0105] 7) After the machining is completed, the laser module, the coupling water cavity module, the stabilized high-pressure water module, the CCD machine vision monitoring module, and the ultrasonic vibration module are turned off, the machine tool is turned off, and the workpiece is taken off from the workbench; steps 1-6 are cycled to perform the next machining.

[0106] The laser module is adjusted so that the focal point of the laser spot coincides with the center of the nozzle, and the workpiece 13 on the vibration plate 14 is machined, specifically:

[0107] 1-1) The laser 2 outputs a laser beam of a set wavelength according to the set laser parameters, the laser beam is changed direction by the reflecting mirror, and the focal point of the laser spot is formed by the focusing lens;

[0108] 1-2) The position of the focal point of the laser spot in the XY plane is adjusted by adjusting the rotation angle of the reflecting mirror 3, and the Z-direction position of the focal point of the laser spot is adjusted by adjusting the Z-direction displacement of the focusing lens 4;

[0109] 1-3) The laser beam enters the coupling water cavity 7 through the window element 6, and the focal point of the light spot is made to coincide with the center of the nozzle 8 by adjusting the Z-direction displacement of the focusing lens 4;

[0110] 1-4) The host computer controls the high-pressure pump 10 to draw water in the water tank 11 into the coupling water cavity 7, and the water in the coupling water cavity 7 forms a high-pressure water jet 12 through the nozzle 8, which 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 cavity 7 in real time through the overflow valve 9.

[0111] Specifically, step 1-3) is:

[0112] The CCD camera 1 collects images of the movement process of the focal point of the light spot in real time, and the image processor 5 in the host computer processes and analyzes the collected images to ensure that the focal point of the light spot coincides with the center of the nozzle 8;

[0113] Specifically, the CCD camera collects and processes images by the image processor 5 in the host computer, and the step of processing images is:

[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 gradient of each point on the laser spot image, and determine the position with the largest gradient as the edge of the light spot, and connect the points on the edge to form the light spot contour;

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

[0117] 2-4) According to the position of the light spot center and the center of the nozzle, the displacement vector of the laser spot is obtained, and the rotation angle of the reflector 3 and the Z-direction displacement of the focusing lens 4 are adjusted to make the light spot center move along the displacement vector to the center of the nozzle;

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

[0119] Example 1:

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

[0121] The water in the water tank 11 is delivered to the coupling water cavity 7 by the high-pressure pump 10, and the water pressure in the coupling water cavity 7 is adjusted by the overflow valve 9. The movement process of the spot focus is collected in real time by the CCD camera 1, and the collected images are 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 frequency and amplitude of each ultrasonic transducer 15, the ultrasonic wave 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 with the vibration plate 14, and forms ultrasonic vibration with the vibration plate 14.

[0123] As shown in Figure 2 In this embodiment, the ultrasonic transducers 15 are arranged in a 4x5 matrix under the vibration plate, the sound field formed by each ultrasonic transducer is superimposed to form an interference sound field on the workpiece, which enhances the vibration of the machining area and weakens the vibration of other positions, and the vibration signals of each point of the workpiece are transmitted to the controller 18 through the amplitude sensor 19 to form a closed-loop control. The energy of ultrasonic vibration is transmitted to the machining area, which can promote the rapid separation of the machining product from the substrate, and the machining product is quickly discharged from the machining area under the scouring action of the water jet 12; at the same time, the vibration of other positions is inhibited, which can reduce the influence of vibration on the clamping stability.

[0124] Embodiment 2:

[0125] The application also discloses a matrix ultrasonic vibration assisted liquid guide laser processing system and a processing method thereof, which can realize high-quality and high-efficiency machining of large thin-walled workpieces, large-depth-to-diameter ratio micro-holes and surface micro-structures, as shown in Figure 3 The application also discloses a matrix ultrasonic vibration assisted liquid guide laser processing system and a processing method thereof, which can realize high-quality and high-efficiency machining of large thin-walled workpieces, large-depth-to-diameter ratio micro-holes and surface micro-structures, as shown in

[0126] 1) The workpiece to be machined is clamped on the workbench of the machine tool and locked by the locking mechanism.

[0127] 2) Turn on the machine tool and set the machining track and machining parameters.

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

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

[0130] 5) Adjust the high-pressure pump and the overflow valve to stabilize the water pressure in the coupled water cavity to 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 reflecting mirror, the Z-direction distance between the focusing lens and the window element, so that the focal point of the laser spot coincides with the center of the nozzle.

[0134] 9) Perform ultrasonic-assisted liquid-guided laser processing on the workpiece according to the processing trajectory and processing parameters set in step 2, and the frequency and amplitude of the ultrasonic transducer are automatically adjusted by the controller according to the processing trajectory and the shape of the workpiece.

[0135] 10) After processing, turn off the laser module, the coupled water cavity module, the stable high-pressure water module, the CCD machine vision inspection and monitoring module, and the ultrasonic vibration module, turn off the machine tool, and take the workpiece off the workbench.

[0136] The matrix ultrasonic-assisted liquid-guided laser processing system and the processing method thereof disclosed by the present application adopt an m x n matrix ultrasonic transducer arrangement mode to form an interference acoustic field on the surface of a workpiece, and use an optimization algorithm to adjust the frequency and amplitude of each ultrasonic transducer in real time according to the change of the processing area position and the shape of the workpiece, so that the ultrasonic vibration of the processing area is strengthened and the vibration of the remaining positions is weakened, which can effectively solve the problem of poor processing quality and reduced processing capacity caused by the failure of the processing products to be discharged in time during liquid-guided laser processing, and can also reduce the impact of high-power ultrasonic vibration on the clamping stability of the workpiece, thereby realizing high-quality and high-efficiency processing of large thin-walled workpieces, large-depth-ratio micro-holes, and surface micro-structures.

[0137] The above description is only an embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A matrix-type ultrasonic-assisted liquid-guided laser processing system, characterized in that, Includes: host computer and connected to it laser module, coupling water cavity module, ultrasonic vibration module, stabilizing high-pressure water module and CCD machine vision inspection module; The laser module is used to receive control commands from the host computer, turn on the output of a laser beam of a specific wavelength, and focus it into the coupling water cavity module; The coupling water cavity module is located 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). The ultrasonic vibration module is located below the coupling water cavity module and is used to fix the workpiece (13) and generate ultrasonic vibration on the workpiece (13); The ultrasonic vibration module includes: a vibrating plate (14), an ultrasonic transducer (15), an ultrasonic generator (16), a controller (18), and an amplitude sensor (19). The vibrating plate (14) is a plate-shaped structure, and an ultrasonic transducer (15) is provided below the vibrating plate (14); a workpiece (13) is provided on the vibrating plate (14), and the vibrating plate (14) and the workpiece (13) are rigidly connected. The controller (18) is connected to the ultrasonic transducer (15) via the ultrasonic generator (16) and is used to control the ultrasonic transducer (15) to generate ultrasonic vibrations and transmit them to the vibrating plate (14). The ultrasonic generator (16) is used to generate a high-frequency alternating current signal and transmit it to the ultrasonic transducer (15). The amplitude sensor (19) is fixed above the workpiece (13) and connected to the controller (18) to collect vibration signals on the workpiece (13) and feed them back 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 vibrating plate (14), and each ultrasonic transducer (15) outputs a vibration frequency and amplitude separately, so that the ultrasonic vibration in the processing area is strengthened and the vibration in other positions is weakened. The pressure-stabilizing high-pressure water module is connected to the coupling water cavity module to supply water to the coupling water cavity module and regulate the water pressure of the coupling water cavity module. The CCD machine vision inspection module is located above the laser module and is used to collect the position of the laser beam spot focus 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 spot focus and the position of the nozzle (8) of the coupling water cavity module so as to make the laser beam coincide with the nozzle (8) of the coupling water cavity module.

2. The matrix-type ultrasonic-assisted liquid-guided laser processing system according to claim 1, characterized in that, The laser module includes: a laser (2), a reflector (3), and a focusing lens (4); The laser (2) is horizontally fixed on the fixture and connected to the host computer. It receives the control command from the host computer to turn on and emits a laser beam to the reflector (3). The emitting end of the laser (2) is coaxially arranged with the reflector (3); the angle between the reflector (3) and the horizontal plane is 0 degrees to 90 degrees, so as to reflect the laser beam emitted by the laser (2) onto the focusing lens (4) located directly below the reflector (3); The reflector (3) and the focusing lens (4) are coaxially arranged; the focusing lens (4) is located directly above the coupling water cavity module; by adjusting the rotation angle of the reflector (3) to change the position of the XY plane of the light spot focus, 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-type 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 located directly below the CCD machine vision inspection module and is coaxial with the field of view axis of the CCD machine vision inspection module. A reflector (3) and a focusing lens (4) are provided between the window element (6) and the CCD machine vision inspection 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 adjusted by the host computer so that the focal spot coincides with the center of the nozzle (8). The water in the coupling water cavity (7) forms a high-pressure water jet through the nozzle (8). The high-pressure water jet guides the laser to the surface of the workpiece (13) to achieve material removal.

4. The matrix-type ultrasonic-assisted liquid-guided laser processing system according to claim 1, characterized in that, The pressure-stabilizing 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 chamber (7) through a high-pressure pump (10) and an overflow valve (9) arranged in parallel; The high-pressure pump (10) is used to draw water from the water tank (11) and deliver it to the coupling water chamber; The overflow valve (9) is used to regulate the water pressure in the coupling water chamber (7).

5. The processing method of the matrix-type ultrasonic-assisted liquid-guided laser processing system according to claim 1, characterized in that, Includes the following steps: 1) Clamp the workpiece (13) to be processed on the machine tool table and lock it by locking mechanism; turn on the machine tool and set the processing trajectory and processing parameters; 2) Start the laser module, the high-pressure water module, the CCD machine vision inspection module and the ultrasonic vibration module through the host computer to ensure that the laser (2) emits light normally, the coupling water cavity pressure is stable, the water jet is stable, the CCD camera captures images normally, and the ultrasonic vibration is stable; 3) Adjust the laser parameters to ensure the laser output meets the processing requirements; adjust the high-pressure pump and overflow valve to ensure the coupling water cavity pressure meets the processing requirements, so that the water jet can be transmitted stably over long distances; 4) The position of the laser spot is monitored in real time using a CCD camera (1). The collected image data is processed and analyzed in the image processor (5) of the host computer to obtain the light intensity values ​​of each pixel of the laser spot. 5) Turn on the ultrasonic generator (16) and controller (18) to set the initial output of ultrasonic vibration; and adjust the laser module so that the laser spot focus coincides with the nozzle center, and process the workpiece (13) on the vibrating plate (14); 6) The controller (18) configures the frequency and amplitude of each ultrasonic transducer (15) according to the processing trajectory and workpiece shape set in step 1), and adjusts the ultrasonic generator (16) in real time according to the vibration signal transmitted back by the amplitude sensor (19). 7) Once processing is complete, shut down the laser module, coupling water cavity module, stabilizing high-pressure water module, CCD machine vision inspection module, and ultrasonic vibration module. Turn off the machine tool and remove the workpiece from the worktable. Repeat steps 1) to 6) for the next processing cycle.

6. The processing method of the matrix-type ultrasonic-assisted liquid-guided laser processing system according to claim 5, characterized in that, The laser adjustment module aligns the laser spot focal point with the nozzle center and processes the workpiece (13) on the vibrating plate (14), specifically as follows: 1-1) The laser (2) outputs a laser beam of a set wavelength according to the set laser parameters. The laser beam is redirected by a reflector and forms a laser spot focal point by a focusing lens. 1-2) Adjust the rotation angle of the reflector (3) to change the position of the focal point on the XY plane, and adjust the Z-direction displacement of the focusing lens (4) to adjust the Z-direction position of the focal point; 1-3) The laser beam enters the coupling water cavity (7) through the window element (6), and the focal point of the beam coincides with the center of the nozzle (8) by adjusting the Z-direction displacement of the focusing lens (4); 1-4) The host computer controls the high-pressure pump (10) to draw 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 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).

7. The processing method of the matrix-type ultrasonic-assisted liquid-guided laser processing system according to claim 6, characterized in that, Steps 1-3 are specifically as follows: The CCD camera (1) acquires images of the movement process of the light spot focus in real time. The image processor (5) in the host computer processes and analyzes the acquired images to ensure that the light spot focus coincides with the center of the nozzle (8). Specifically, the image processing and analysis of the acquired images by the image processor (5) in the host computer includes: 2-1) Based on the light intensity, each pixel in the laser spot image data is represented by a value between 0 and 255; 2-2) Calculate the gradient of each point on the laser spot image, determine the position with the largest gradient as the edge of the spot, and connect the points of the spot edge to form the spot outline; 2-3) Calculate the position of the center of the light spot based on its outline; 2-4) Based on the position of the center of the laser spot and the position of the nozzle center, the displacement vector of the laser spot is obtained. The rotation angle of the reflector (3) and the Z-direction displacement of the focusing lens (4) are controlled to adjust the center of the laser spot to move closer to the nozzle center along the displacement vector. 2-5) When the displacement vector is 0, the adjustment is complete.

8. The processing method of the matrix-type ultrasonic-assisted liquid-guided laser processing system according to claim 7, characterized in that, The controller (18) configures the frequency and amplitude of each ultrasonic transducer (15) according to the processing trajectory and workpiece shape set in step 1), and adjusts the ultrasonic generator (16) in real time according to the vibration signal transmitted back by the amplitude sensor (19), specifically: The controller (18) configures the required frequency and amplitude of each ultrasonic transducer (15), and the ultrasonic generator (16) generates a high-frequency AC 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 vibrating plate (14). The workpiece (13) forms ultrasonic vibration with the vibrating plate (14). The sound field generated by each ultrasonic transducer (15) is superimposed to form an interference sound field on the workpiece (13), which enhances the vibration of the processing area and weakens the vibration of other positions. The vibration signal of each point of the workpiece (13) is transmitted to the controller (18) through the amplitude sensor (19). The controller (18) adjusts the ultrasonic generator (16) in real time based on the data fed back by the amplitude sensor (19).

9. The processing method of the matrix-type ultrasonic-assisted liquid-guided laser processing system according to claim 8, characterized in that, The real-time adjustable ultrasonic generator (16) includes the following steps: 3-1) The displacement of each test point on the workpiece (13) is detected by the amplitude sensor (19); 3-2) Find all peak and valley values ​​in the displacement data of a certain test point, calculate the average value of all peak values ​​and the average value of valley values ​​and take the difference, and select 1 / 2 of the difference as the amplitude of the point; 3-3) The difference between the actual amplitude obtained from the test and the optimal amplitude calculated theoretically is used to obtain the difference between the actual amplitude and the optimal amplitude at each test point. This difference is defined as the amplitude deviation. When the amplitude deviation is within the set allowable range, processing continues; when the amplitude deviation is outside the set allowable range, vibration optimization is performed. 3-4) Using the output frequency and amplitude of the ultrasonic transducer (15) as input, and taking the minimum amplitude deviation as the optimization target, vibration optimization is performed to obtain the frequency and amplitude of each ultrasonic transducer (15) that minimizes the amplitude deviation. 3-5) Control the output of each ultrasonic transducer (15) to update to the optimal frequency and amplitude, and retest the displacement of each test point. Iterate from step 3-1) to step 3-5) until the amplitude deviation is always within the set allowable range.

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