A method and system for optimizing laser cutting control of thick metal plates

Abstract

This invention provides a method and system for controlling and optimizing laser cutting of thick metal plates. The method involves acquiring a multi-dimensional parameter set of the thick metal plate, including its thickness, material properties, and thermal diffusivity. The plasma density of the thick metal plate is obtained in real time using this multi-dimensional parameter set. The polarization state of the laser is then jointly adjusted based on the plasma density. Energy waveform time-varying control is applied to the thick metal plate according to the multi-dimensional parameter set, and the laser thermal parameters are adjusted accordingly. The surface of the thick metal plate is detected based on the multi-dimensional parameter set, and if cracks are found, a healing operation is performed. By jointly adjusting the polarization state, regulating the laser thermal parameters, and performing the healing operation, the laser cutting of the thick metal plate is jointly controlled and optimized, thereby improving the quality and efficiency of laser cutting.

Description

Technical Field

[0001] This invention belongs to the field of laser cutting technology, and more specifically, relates to a laser cutting control optimization method and system for thick metal plates. Background Technology

[0002] As high-end equipment manufacturing develops towards heavier and more precise directions, high-quality and efficient cutting of thick metal plates has become a core process requirement in fields such as energy equipment. Traditional laser cutting mainly relies on static parameter combinations, which have a single control dimension and are difficult to coordinate multi-field coupling effects, often making it difficult to cope with the unique energy attenuation and defect control problems of thick plate cutting.

[0003] Most existing solutions focus on controlling a single physical process, lacking coordinated handling of key issues such as plasma density and subsurface crack propagation. They also cannot adapt to dynamic changes in material properties and working conditions. When cutting thick metal plates, defects such as excessive kerf taper and microcrack initiation still exist. Therefore, there is an urgent need for a laser cutting optimization method that integrates multi-physics sensing and cross-scale collaborative control to improve the cutting quality and efficiency of thick metal plates through the optical-thermal-mechanical coupling mechanism. Summary of the Invention

[0004] In view of the aforementioned problems, and in conjunction with the first aspect of the present invention, embodiments of the present invention provide a laser cutting control optimization method for thick metal plates, the method comprising:

[0005] Obtain a multidimensional parameter set for a thick metal plate, the multidimensional parameter set including the thickness parameter of the thick metal plate, the material properties of the thick metal plate, and the material thermal diffusivity parameter of the thick metal plate;

[0006] The plasma density of the thick metal plate is obtained in real time based on the multidimensional parameter set, and the polarization state of the laser is jointly adjusted based on the plasma density.

[0007] Based on the multidimensional parameter set, the energy waveform time-conditioning is applied to the metal thick plate, and the laser heat parameters are adjusted based on the energy waveform time-conditioning.

[0008] The surface of the thick metal plate is detected based on the multi-dimensional parameter set. If cracks are found, a healing operation is performed based on the cracks.

[0009] This study optimizes the joint control of laser cutting of thick metal plates based on polarization state adjustment, laser thermal parameter regulation, and healing operation.

[0010] As a further aspect of the present invention, the step of obtaining the plasma density of the thick metal plate in real time based on the multidimensional parameter set, and performing joint polarization state adjustment of the laser based on the plasma density, includes:

[0011] The joint adjustment of polarization state includes a primary adjustment of polarization state and a secondary adjustment of polarization state;

[0012] The plasma density of the thick metal plate is obtained in real time based on the material properties. At the same time, the density range is divided, and the plasma density is compared with the density range to obtain the comparison result. Based on the comparison result, the polarization state of the laser is adjusted once to obtain the real-time laser transmittance parameter. The laser transmittance parameter is adjusted again based on the polarization state, which includes linear polarization, elliptic polarization, and circular polarization.

[0013] As a further aspect of the present invention, the primary adjustment of the polarization state and the secondary adjustment of the polarization state include:

[0014] A first density threshold and a second density threshold are set, which are used to distinguish polarization states;

[0015] If the plasma density of the thick metal plate is less than the first density threshold, the laser maintains linear polarization.

[0016] If the plasma density of the thick metal plate is greater than or equal to the first density threshold and less than or equal to the second density threshold, the laser is switched to elliptic polarization.

[0017] If the plasma density of the thick metal plate is greater than the second density threshold, the laser will remain circularly polarized.

[0018] A threshold for the laser transmittance parameter is set, and the polarization state is adjusted a second time based on the real-time laser transmittance parameter and the threshold for the laser transmittance parameter.

[0019] If the real-time laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold, then maintain the current polarization state;

[0020] If the real-time laser transmittance parameter is less than the laser transmittance parameter threshold, adjust the polarization ellipticity until the real-time laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold.

[0021] When the polarization ellipticity is increased, the laser transmittance parameter also increases. Based on the increase in polarization ellipticity, the real-time laser transmittance parameter is increased. The polarization ellipticity is adjusted once every 100 microseconds to obtain the real-time laser transmittance parameter until the laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold.

[0022] As a further aspect of the present invention, the step of applying energy waveform time-varying control to the thick metal plate based on the multidimensional parameter set, and adjusting the laser thermal parameters based on the energy waveform time-varying control, includes:

[0023] The energy waveform timing mechanism includes time waveform modulation and spatial phase modulation;

[0024] The time waveform modulation adjusts the laser thermal parameters by controlling the time parameters;

[0025] The spatial phase modulation adjusts the laser thermal parameters by controlling the temperature parameters.

[0026] As a further aspect of the present invention, the time waveform modulation includes:

[0027] The thickness modulation coefficient is obtained based on the thickness parameter, the basic energy amplitude is obtained based on the material properties, and the modulation frequency is obtained based on the thickness parameter and the thickness modulation coefficient.

[0028] A time modulation model is constructed based on the thickness modulation coefficient, the basic energy amplitude, and the modulation frequency. The laser waveform is then modulated based on the time modulation model.

[0029] As a further aspect of the present invention, the spatial phase modulation includes:

[0030] The laser wavelength is obtained, the refractive index of the metal plate is obtained, and the thickness gradient factor is obtained based on the laser wavelength, the thickness parameter, and the refractive index of the material.

[0031] The laser cross-sectional coordinates are obtained, and a spatial modulation model is constructed based on the thickness gradient factor and the laser cross-sectional coordinates. The laser is then spatially phase modulated based on the spatial modulation model.

[0032] As a further aspect of the present invention, the step of detecting the surface of a thick metal plate based on the multidimensional parameter set, and performing a healing operation based on the crack if a crack is found, includes:

[0033] If there are cracks on the surface of a thick metal plate, obtain crack depth parameters and crack propagation rate parameters, obtain the local minimum heat flux density based on crack depth parameters and crack propagation rate parameters, and obtain the real-time local heat flux density. The surface of the thick metal plate includes the surface of the metal and the subsurface of the metal.

[0034] If the real-time local heat flux density is greater than or equal to the local minimum heat flux density, then the current parameters are maintained and the operation continues. The current parameters include the laser pulse parameters and the laser pulse width parameters.

[0035] If the real-time local heat flux density is less than the local minimum heat flux density, then the crack is healed.

[0036] As a further aspect of the present invention, the healing operation includes:

[0037] The crack area is obtained, the material absorptivity of the metal plate is obtained, and the laser pulse parameters required to repair the crack are obtained based on the crack area, the material absorptivity of the metal plate, and the local minimum heat flux density. The laser pulse parameters are expressed as the power required to emit the laser.

[0038] The highest temperature parameter of the laser during cutting is obtained, and the superheat parameter that causes cracks in the thick metal plate is obtained. Based on the highest temperature parameter, the superheat parameter, the crack depth parameter, and the crack propagation rate parameter, the laser pulse width parameter is obtained, and the laser pulse width parameter is represented by the duration of the laser pulse parameter.

[0039] As a further aspect of the present invention, the joint control optimization of laser cutting of thick metal plates based on polarization state joint adjustment, adjustment of laser thermal parameters, and healing operation includes:

[0040] The laser transmittance parameter is adjusted based on the aforementioned polarization state.

[0041] The healing operation is based on the laser pulse parameters and laser pulse width parameters;

[0042] The control module adjusts the laser transmittance parameters, laser heat parameters, laser pulse parameters, and laser pulse width parameters to jointly optimize the laser cutting of thick metal plates.

[0043] Furthermore, embodiments of the present invention also provide a laser cutting control optimization system for thick metal plates, comprising:

[0044] The acquisition module is used to acquire the thickness parameters, material properties, and thermal diffusivity parameters of the metal plate, and to acquire the plasma density of the metal plate in real time based on the multidimensional parameter set.

[0045] An adjustment module is used to apply energy waveform time-varying control to the metal plate based on the multi-dimensional parameter set, and to adjust the laser heat parameters based on the energy waveform time-varying control.

[0046] The detection module detects the surface of the thick metal plate based on the multidimensional parameter set.

[0047] A healing module, which performs a crack healing operation;

[0048] The control module performs joint control optimization for laser cutting of thick metal plates based on polarization state joint adjustment, adjustment of laser thermal parameters, and healing operation.

[0049] Based on the above aspects, the embodiments of this application realize the acquisition of a multi-dimensional parameter set of a thick metal plate, the real-time acquisition of the plasma density of the thick metal plate through the multi-dimensional parameter set, the real-time laser transmittance parameter by adjusting the polarization state of the laser through the plasma density, the adjustment of the laser transmittance parameter through the secondary adjustment of the polarization state, the energy waveform time-varying control of the thick metal plate through the multi-dimensional parameter set, the adjustment of the laser heat parameter based on the energy waveform time-varying control, the crack detection of the surface of the thick metal plate through the multi-dimensional parameter set, the crack healing operation through the healing operation, and the joint control optimization of the laser cutting of the thick metal plate by adjusting the laser transmittance parameter, adjusting the laser heat parameter, and the healing operation.

[0050] By acquiring parameters such as plasma density and laser transmittance, multi-physics layer sensing fusion is performed. The laser transmittance is adjusted by acquiring the plasma density of the thick metal plate. The laser thermal parameters are adjusted by real-time energy waveform control of the thick metal plate. Cracks in the thick metal plate are healed by local minimum heat flux density and real-time local heat flux density. Based on the analysis of multi-dimensional laser parameters and the repair of cracks in the thick metal plate, cross-scale collaborative control of the optical-thermal-mechanical coupling mechanism is achieved, thereby improving the quality and efficiency of laser cutting of thick metal plates. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the execution flow of a laser cutting control optimization method for thick metal plates provided in an embodiment of the present invention.

[0052] Figure 2 This is a schematic diagram of a laser cutting control optimization system for thick metal plates provided in an embodiment of the present invention. Detailed Implementation

[0053] The present invention will now be described in detail with reference to the accompanying drawings. Figure 1 This is a schematic diagram of the execution flow of a laser cutting control optimization method for thick metal plates according to an embodiment of the present invention. The laser cutting control optimization method for thick metal plates will be described in detail below.

[0054] Step S1: Obtain a multi-dimensional parameter set of the metal plate, which includes the thickness parameter of the metal plate, the material properties of the metal plate, and the material thermal diffusivity parameter of the metal plate.

[0055] For example, the multidimensional parameter set of metal plate A: low carbon steel plate, thickness value of 80mm, material thermal diffusivity. The multi-dimensional parameter set of metal plate B: stainless steel plate, thickness value 70mm, material thermal diffusivity .

[0056] Step S2: Based on the multidimensional parameter set, the plasma density of the thick metal plate is obtained in real time, and the polarization state of the laser is jointly adjusted based on the plasma density.

[0057] In this embodiment, step S2 includes:

[0058] Step S21, the joint adjustment of polarization state includes primary adjustment of polarization state and secondary adjustment of polarization state. Based on the material properties, the plasma density of the metal plate is obtained in real time, and density intervals are divided. The plasma density is compared with the density intervals to obtain the comparison results. Based on the comparison results, the polarization state of the laser is adjusted first to obtain the real-time laser transmittance parameter. Based on the secondary adjustment of polarization state, the laser transmittance parameter is adjusted. The polarization state includes linear polarization, elliptic polarization, and circular polarization.

[0059] It should be noted that when laser cutting thick metal plates, the plasma density increases nonlinearly with the thickness of the metal plate. Thin metal plates generate only low-density plasma due to the rapid penetration of energy, while thick metal plates experience a jump in plasma density due to the extended residence time in the molten pool. Thick metal plates also experience avalanche ionization due to multiple reflections and energy accumulation. This thickness-dependent plasma behavior dynamically shields the laser energy. The transmittance of thin metal plates can reach over 70%, while that of thick metal plates drops sharply to below 30%, resulting in an exponential decay of the bottom energy in traditional processing.

[0060] It should be noted that laser transmittance refers to the proportion of laser energy that penetrates a material or medium, quantified as the ratio of transmitted light intensity to incident light intensity. In this embodiment, by dynamically controlling polarization, laser transmittance is improved, reducing energy loss caused by the plasma shielding effect, thereby increasing the bottom energy density during the cutting of thick metal plates. It should also be noted that polarization state is a physical quantity describing the directional characteristics of the electric field vibration of a light wave, characterizing the spatial orientation and temporal variation of the electric field vector during electromagnetic wave propagation. Common polarization states include linear polarization, circular polarization, and elliptical polarization, the differences stemming from the phase difference and amplitude ratio between two orthogonal electric field components. In laser processing, dynamically controlling the polarization state using devices such as liquid crystal phase retarders can alter the interaction mechanism between the laser and the material, thereby optimizing energy transmission efficiency. Precise control of the polarization state has become one of the core technical dimensions for improving laser cutting quality.

[0061] Furthermore, during the laser cutting process, the first adjustment quickly matches the basic polarization mode (linear / elliptical / circular polarization) through plasma density to meet the energy transmission requirements under different working conditions. The second adjustment (fine-tuning of polarization ellipticity) further optimizes the transmittance under the selected mode. By dynamically adjusting the phase delay, the laser energy transmittance is kept stable at greater than or equal to 95%. This two-stage control strategy takes into account both response speed and accuracy, avoids energy loss caused by plasma abrupt changes, and maximizes transmittance through closed-loop feedback, ultimately improving cutting efficiency and quality.

[0062] In this embodiment, compared with the fixed polarization state or single parameter adjustment in the prior art, the two-stage polarization control combines response speed and steady-state accuracy by responding to the changes in plasma density in layers and coordinating control. It is particularly suitable for the dynamic changes in plasma during thick plate cutting, thus improving control accuracy and adaptability.

[0063] Step S22: Set a first density threshold and a second density threshold, which are used to distinguish polarization states.

[0064] If the plasma density of the thick metal plate is less than the first density threshold, the laser maintains linear polarization.

[0065] It should be noted that the electric field vector of a linearly polarized laser always vibrates along a single plane during propagation, exhibiting a strictly linear trajectory. During laser cutting, the interaction between the linearly polarized laser and the material is direction-dependent. When the polarization direction is parallel to the cutting direction, the absorption rate of light by the thick metal plate is high, but it is prone to energy scattering due to plasma resonance.

[0066] If the plasma density of the thick metal plate is greater than or equal to the first density threshold and less than or equal to the second density threshold, the laser will switch to elliptical polarization.

[0067] It should be noted that the trajectory of the endpoint of the electric field vector of an elliptical laser is elliptical, which can be regarded as a linear combination of linear polarization and circular polarization. The ratio of its major and minor axes and the phase difference determine the anisotropic characteristics of the energy distribution. In laser welding, it can achieve a controllable gradient distribution of heat input, with a larger penetration depth in the major axis direction and a narrower heat-affected zone in the minor axis direction. It is particularly suitable for adjusting thermal matching when joining dissimilar metals.

[0068] If the plasma density of the thick metal plate is greater than the second density threshold, the laser will remain circularly polarized.

[0069] It should be noted that the electric field vector of a circularly polarized laser moves in a spiral motion with a constant amplitude, forming a perfect circle when projected onto a plane. Its non-directional energy distribution can eliminate anisotropic effects during processing, avoid polygonal holes when drilling metals, and make the molten pool convection symmetrical in additive manufacturing. It is especially suitable for uniform energy coupling of highly reflective materials.

[0070] For example, the first density threshold is set to Set the second density threshold to When cutting 80mm thick stainless steel, if the plasma density remains below the first density threshold and linearly polarized laser is used continuously, the plasma density will suddenly increase to... In traditional methods, the continuous use of linearly polarized lasers causes a sharp drop in laser transmittance, resulting in insufficient energy at the bottom and ultimately severe slag buildup. In this case, the linearly polarized laser should be switched to an elliptical polarized laser.

[0071] Step S23: Set the laser transmittance parameter threshold, and perform secondary adjustment of the polarization state based on the real-time laser transmittance parameter and the laser transmittance parameter threshold.

[0072] If the real-time laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold, then the current polarization state is maintained.

[0073] If the real-time laser transmittance parameter is less than the laser transmittance parameter threshold, adjust the polarization ellipticity until the real-time laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold.

[0074] When the polarization ellipticity is increased, the laser transmittance parameter also increases. Based on the increase in polarization ellipticity, the real-time laser transmittance parameter is increased. The polarization ellipticity is adjusted once every 100 microseconds to obtain the real-time laser transmittance parameter until the laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold.

[0075] It should be noted that the transmittance of laser light in a material varies non-linearly with the ellipticity of elliptically polarized light, i.e., the ratio of its short to long axis. When it approaches linear polarization, the transmittance is affected by the coupling effect between the polarization direction and the lattice orientation of the material. As the ellipticity increases to circular polarization, its isotropy is enhanced, which significantly suppresses the plasma shielding effect that stabilizes the transmittance. For example, when welding a 70mm thick copper plate, the transmittance of circular polarization is more than twice that of linear polarization. Medium ellipticity, due to its combination of directional penetration and uniform heat distribution, becomes the optimal choice for deep penetration welding. The aforementioned medium ellipticity is expressed as its ratio of its short to long axis is approximately 0.5.

[0076] For example, if the laser transmittance parameter threshold is set to 95%, and the obtained real-time laser transmittance parameter is 97%, which is greater than the above laser transmittance parameter threshold, the ellipticity of the current elliptic polarization can be maintained. If the obtained real-time laser transmittance parameter is 94%, which is less than the above laser transmittance parameter threshold, the ellipticity is continuously adjusted until the real-time laser transmittance parameter is greater than or equal to 95%.

[0077] Step S3: Apply energy waveform time-varying control to the metal plate based on the multidimensional parameter set, and adjust the laser heat parameters based on the energy waveform time-varying control.

[0078] In this embodiment, step S3 includes:

[0079] Step S31, the energy waveform timing mechanism includes time waveform modulation and spatial phase modulation.

[0080] Specifically, energy waveform timing control achieves three-dimensional adaptive distribution of laser energy in thick metal plate cutting by synchronously controlling the time dimension waveform and spatial dimension phase of the laser. This solves the problem of uneven energy deposition in traditional continuous laser cutting, such as surface overheating and insufficient energy at the bottom.

[0081] The time waveform modulation adjusts the laser thermal parameters by controlling the time parameters.

[0082] Specifically, the aforementioned time waveform modulation includes an oscillation term and a Gaussian term. The oscillation term represents the superposition of periodic fluctuations within the pulse duration, while the Gaussian term represents the confinement of energy, concentrating it in the central period. The time generation refers to the duration during which the laser acts on the thick metal plate.

[0083] The spatial phase modulation adjusts the laser thermal parameters by controlling the temperature parameters.

[0084] Specifically, the aforementioned spatial phase modulation includes a vortex term and a cone phase term. The vortex term forms a ring-shaped laser spot with zero intensity at its center, while the cone phase term generates a Bessel laser without diffraction. The temperature parameter represents the temperature corresponding to this laser.

[0085] Step S32: Obtain the thickness modulation coefficient based on the thickness parameter, obtain the basic energy amplitude based on the material properties, and obtain the modulation frequency based on the thickness parameter and the thickness modulation coefficient.

[0086] Specifically, the thickness of the metal plate is obtained through the acquisition module, and a thickness modulation coefficient is obtained based on the thickness of the metal plate. The thickness modulation coefficient is used to control the oscillation amplitude, and its value ranges from 0.3 to 1.2. Its value increases as the thickness of the metal plate increases. Different basic energy amplitudes are obtained through metal plates of different materials. The basic energy amplitude is determined by the material threshold. The modulation frequency is obtained through the thickness parameter and the thickness modulation coefficient.

[0087] For example, a low-carbon steel plate A is obtained. The thickness of the metal plate A is 80 mm. The thickness modulation coefficient of the metal plate A is 1. The basic energy amplitude of the metal plate A is 15-40 J / cm². The modulation frequency of the metal plate A is 4 kHz.

[0088] A time modulation model is constructed based on the thickness modulation coefficient, the basic energy amplitude, and the modulation frequency. The laser waveform is then modulated based on the time modulation model.

[0089] Specifically, the time waveform modulation includes an oscillation term and a Gaussian term, denoted as... ,in Let be the laser energy density at time t. This represents the thickness modulation coefficient for thick metal plates. This represents the modulation frequency of a thick metal plate. Indicated as an oscillation term, Represented as Gaussian terms, This is expressed as thermal diffusivity, used to control pulse width and suppress heat accumulation. Specifically, it is expressed as... , Represented as characteristic heat conduction time , which represents the pulse center time, and the pulse center time is determined by the cutting speed.

[0090] It should be noted that before time waveform modulation, the laser energy density, oscillation term, and Gaussian term at time t are preprocessed to unify their dimensions. Specifically, the laser energy density at time t is converted into a dimensionless absolute value, and the laser energy density at time t is divided by the maximum output energy density of the laser to constrain its value range to the interval [0, 1]. The amplitude normalization factor is used to constrain the value range of the oscillation term to the interval [0, 1]. A time normalization parameter is introduced to constrain the value range of the Gaussian term to the interval [0, 1].

[0091] It should be noted that the core advantage of time waveform modulation lies in the realization of time-space harmonic distribution of pulse energy. Under the condition of maintaining the total energy constant, the dynamic oscillation component actively decouples the heat demand of the surface and the bottom. The peak phase enhances the penetration of the bottom of the molten pool to overcome the plasma shielding effect, while the trough phase periodically interrupts the surface heat input to trigger micro-region rapid cooling. In conjunction with the precise time-domain focusing characteristics of Gaussian envelope, the three work together to reconstruct the heat flow distribution in the time domain dimension, ultimately achieving a triple breakthrough of efficient bottom penetration, real-time surface temperature control, and miniaturization of the heat-affected zone. This completely avoids the surface overheating and thermal damage caused by the continuous high heat flow of traditional rectangular pulses, while improving cutting quality and energy efficiency ratio, reducing slag buildup and improving energy efficiency.

[0092] Step S33: Obtain the laser wavelength, obtain the refractive index of the metal plate, and obtain the thickness gradient factor based on the laser wavelength, the thickness parameter, and the refractive index of the material.

[0093] It should be noted that laser wavelength refers to the output wavelength of the laser, which is an important parameter of the laser beam output by the laser.

[0094] The laser cross-sectional coordinates are obtained, and a spatial modulation model is constructed based on the thickness gradient factor and the laser cross-sectional coordinates. The laser is then spatially phase modulated based on the spatial modulation model.

[0095] Specifically, the laser wavelength is obtained, the refractive index of the metal plate is obtained, and the thickness gradient factor is obtained through the laser wavelength, the refractive index of the metal plate, and the thickness parameter of the metal plate. The laser cross-sectional coordinates are represented as the coordinate parameters of the laser in the cross-section of the metal plate.

[0096] Furthermore, the cross-section of the thick metal plate is obtained, and a rectangular coordinate system is established with the lower left corner of the thick metal plate as the origin, the horizontal direction as the horizontal axis, and the vertical direction as the vertical axis. At the same time, the laser cross-sectional coordinates of the thick metal plate are obtained according to the rectangular coordinate system. A spatial modulation model is constructed through the thickness gradient factor and the laser cross-sectional coordinates, and the laser is spatially phase modulated based on the spatial modulation model.

[0097] Specifically, spatial phase modulation includes vortex terms and cone phase terms, denoted as... , Represented as a vortex term, Represented as a cone-shaped phase term, where Let x and y represent the x-coordinate and y-coordinate of the laser cross-section coordinates of the thick metal plate, respectively. Represented as a thickness gradient factor, the vortex term generates an angular phase gradient to avoid overheating and burning of the laser center, thus ensuring uniform energy enhancement. The conical phase term introduces a radial linear phase delay to enhance bottom penetration.

[0098] Furthermore, the core of polar coordinate response space phase modulation lies in mapping the phase delay and azimuth of the polarization state to the polar coordinate system. Precise polarization control is achieved through independent adjustment of the polar radius and polar angle. The phase delay controls the polarization ellipticity, while the azimuth determines the polarization direction. Decoupling the two can avoid parameter coupling errors in traditional rectangular coordinates. Radial adjustment can compensate for phase distortion caused by plasma in real time, while tangential adjustment can synchronously track changes in the material cutting angle, achieving microsecond-level polarization state optimization and making its dynamic response faster.

[0099] It should be noted that the core advantage of solving the "insufficient bottom penetration" problem through spatial phase modulation lies in achieving three-dimensional directional energy transport. The vortex term generates a ring-shaped light intensity distribution, redistributing energy from the center to the periphery and avoiding the energy attenuation at the center caused by the plasma shielding effect. Meanwhile, the conical phase term endows the laser with axial self-acceleration or Bessel non-diffraction characteristics, significantly enhancing the longitudinal energy deposition efficiency. The synergistic effect of the two suppresses heat diffusion laterally while forming long-range focusing axially, ultimately achieving a triple effect of high aspect ratio processing, bottom energy concentration, and minimization of the heat-affected zone. This is especially suitable for high-quality cutting and drilling of thick plate materials.

[0100] Step S4: Detect the surface of the thick metal plate based on the multidimensional parameter set. If cracks are found, perform a healing operation based on the cracks.

[0101] In this embodiment, step S4 includes:

[0102] Step S41: If there is a crack on the surface of the thick metal plate, obtain the crack depth parameter and crack propagation rate parameter, obtain the local minimum heat flux density based on the crack depth parameter and crack propagation rate parameter, and obtain the real-time local heat flux density. The surface of the thick metal plate includes the surface of the metal and the subsurface of the metal.

[0103] Specifically, the module acquires crack and crack depth parameters on the surface of the thick metal plate using an infrared camera and an ultrasonic sensor. A set of parameters is acquired every 0.1 seconds, and the crack propagation rate parameter is calculated simultaneously. The local minimum heat flux density is then calculated based on the crack depth and crack propagation rate parameters.

[0104] Furthermore, the surface temperature field distribution is acquired by the infrared camera in the acquisition module. Combined with material thermal properties such as thermal conductivity and specific heat capacity, the surface heat flux density is calculated by inversion using the Fourier heat conduction equation. Then, the subsurface electron density and temperature are analyzed in real time by plasma spectral diagnostics. The thermal convection intensity inside the molten pool is inferred by combining the MHD model. Then, the laser phase distortion is measured synchronously by the polarization interferometer in the acquisition module. The plasma refractive index change and energy deposition distribution are correlated by the inverse reconstruction algorithm. The above data are fused by Kalman filtering to output a heat flux density field with a spatial resolution of 100 microseconds and a temporal resolution of 10 microseconds, thus obtaining the real-time local heat flux density.

[0105] It should be noted that the MHD model, by coupling electromagnetic field and hydrodynamic equations and combining real-time plasma spectral data, dynamically analyzes the flow and heat conduction behavior of laser-induced plasma, thereby accurately predicting the heat flux density distribution inside the molten pool, providing a physical basis for polarization state control, and ultimately suppressing heat flux fluctuations to within ±5%, while the heat flux fluctuation of the traditional model is within ±20%, thus improving the quality of the laser-cut surface.

[0106] If the real-time local heat flux density is greater than or equal to the local minimum heat flux density, the current parameters are maintained and the operation continues. The current parameters include the laser pulse parameters and the laser pulse width parameters.

[0107] If the real-time local heat flux density is less than the local minimum heat flux density, then the crack is healed.

[0108] Specifically, during the cutting process, if the metal plate has no cracks, the cutting operation continues. If the metal plate has cracks, the cracks on the surface of the metal plate are acquired by the acquisition module. The surface of the metal plate includes the surface of the metal and the subsurface of the metal. At the same time, the crack depth parameter and crack propagation rate parameter are acquired. The local minimum heat flux density is calculated by back-calculating the crack depth parameter and crack propagation rate parameter. The real-time local heat flux density is also acquired and compared with the local minimum heat flux density. If the real-time local heat flux density is greater than or equal to the local minimum heat flux density, the current parameters are maintained and the operation continues. The current parameters include the laser pulse parameter and the laser pulse width parameter. If the real-time local heat flux density is less than the local minimum heat flux density, the crack is healed.

[0109] It should be noted that in laser processing, the surface refers to the interface layer where the metal and the laser interact directly, and its characteristics determine the initial energy absorption rate. The subsurface refers to the region tens of micrometers to millimeters below the surface, and its plasma density, lattice thermal conductivity, and microcrack propagation directly affect the cutting quality and material strength.

[0110] Furthermore, in laser processing, the reflectivity of the metal surface directly affects the energy coupling efficiency, while the plasma plume and lattice thermal conduction of the subsurface determine the stability of the molten pool. This embodiment optimizes the interaction between the surface and subsurface through two-stage polarization modulation. The first adjustment reduces the surface reflectivity, and the second adjustment suppresses the phase distortion of the laser caused by the subsurface plasma, thereby increasing the energy penetration depth and ultimately achieving synergistic optimization of surface smoothness and the absence of microcracks in the subsurface.

[0111] For example, the local minimum heat flux density can be obtained by back-calculating the crack depth parameter and crack propagation rate parameter. If the obtained real-time local heat flux density is If the current laser pulse parameters and laser pulse width parameters are maintained, the cutting will continue. If the obtained real-time local heat flux density is... If so, it is necessary to adjust the current laser pulse parameters and laser pulse width parameters to change the real-time local heat flux density and perform the crack healing operation.

[0112] Step S42: Obtain the crack area, obtain the material absorptivity of the metal plate, and obtain the laser pulse parameters required to repair the crack based on the crack area, the material absorptivity of the metal plate, and the local minimum heat flux density. The laser pulse parameters are expressed as the power required to emit the laser.

[0113] Specifically, the crack area is obtained, and the material absorptivity of the thick metal plate is also obtained. The laser pulse parameters required to repair the crack are obtained by dividing the product of the crack area and the local minimum heat flux density by the material absorptivity of the thick metal plate.

[0114] Furthermore, the crack area is calculated by multiplying the crack depth and crack length. If the crack is a three-dimensional crack, the area of ​​the three-dimensional crack should be corrected first before obtaining the area of ​​the three-dimensional crack.

[0115] For example, the crack is a two-dimensional crack with a length of 1 mm and a depth of 50 micrometers, and the crack area is obtained as follows: The material absorptivity of the thick metal plate is 30%, and the local minimum heat flux density is obtained as follows: The laser pulse parameters required to repair the crack were calculated to be 0.83W.

[0116] For example, if the crack is a three-dimensional crack, the intersection of the three-dimensional crack is obtained, and the three-dimensional crack is divided into multiple two-dimensional cracks through the intersection. Then, the area of ​​each of the multiple two-dimensional cracks is calculated using the method described above for calculating the crack area of ​​the two-dimensional crack. The area of ​​the three-dimensional crack is obtained by summing the areas of the multiple two-dimensional cracks.

[0117] The highest temperature parameter of the laser during cutting is obtained, and the superheat parameter that causes cracks in the thick metal plate is obtained. Based on the highest temperature parameter, the superheat parameter, the crack depth parameter, and the crack propagation rate parameter, the laser pulse width parameter is obtained, and the laser pulse width parameter is represented by the duration of the laser pulse parameter.

[0118] Specifically, the module acquires the highest temperature parameter of the laser during cutting and the superheat parameter that causes cracks in the thick metal plate. The duration of the laser pulse is then obtained using the highest temperature parameter, superheat parameter, crack depth parameter, and crack propagation rate parameter. ,in, This is expressed as the duration of the laser pulse parameter. This is expressed as a crack depth parameter. This is expressed as a crack propagation rate parameter. This is represented as the highest temperature parameter. This represents the superheat parameter that causes cracks to form in thick metal plates.

[0119] It should be noted that the above formulas have undergone dimension unification. The dimension of the crack depth parameter divided by the crack propagation rate parameter is time, and the dimension of the laser pulse duration is also time. Normalization is performed to constrain the range of its dimensions to the interval [0, 1]. Through the above operations, the dimensions of the above formula are unified.

[0120] Furthermore, taking the crack depth parameter of 50 micrometers as an example, the obtained crack propagation rate parameter is 0.1 millimeters per second, the obtained maximum temperature parameter is 933 degrees Celsius, the obtained superheat parameter that causes cracks in the thick metal plate is 300 degrees Celsius, and the calculated laser pulse duration is 0.39 seconds.

[0121] In summary, the crack was healed by changing the real-time local heat flux density using the laser pulse parameters of 0.83W and 0.39 seconds required for crack repair.

[0122] It should be noted that the laser pulse parameters and the duration of the laser pulse parameters required for repairing the cracks are input into the control module, and the control module uses the laser with the parameters to perform the healing operation on the cracks generated in the thick metal plate.

[0123] Step S5 involves jointly controlling and optimizing the laser cutting of thick metal plates based on polarization state adjustment, adjustment of laser thermal parameters, and healing operation.

[0124] The laser transmittance parameter is adjusted based on the polarization state, and the healing module adjusts the laser pulse parameter and the laser pulse width parameter.

[0125] The control module adjusts the laser transmittance parameters, laser heat parameters, laser pulse parameters, and laser pulse width parameters to jointly optimize the laser cutting of thick metal plates.

[0126] Specifically, the laser transmittance parameter is adjusted by secondary adjustment of the polarization state, the laser pulse parameter and the laser pulse width parameter are adjusted to heal the cracks in the thick metal plate, and the laser heat parameter is adjusted by time waveform modulation and spatial phase modulation. The laser transmittance parameter, laser heat parameter, laser pulse parameter and laser pulse width parameter are input to the control module, and the control module performs joint control optimization of the laser cutting of the thick metal plate through the above parameters.

[0127] Furthermore, the plasma density, local minimum heat flux density, real-time local heat flux density, thickness of the metal plate, and laser cross-sectional coordinates are obtained. Based on the analysis of multi-dimensional laser parameters and the repair of cracks in the metal plate, joint control optimization is achieved. This embodiment uses a laser cutting optimization method that integrates multi-physics field perception and cross-scale collaborative control. Through the optical-thermal-mechanical coupling mechanism, the cutting quality and efficiency of metal plates are improved.

[0128] It should be noted that most existing laser cutting methods for thick metal plates optimize a single value and then adjust the laser accordingly. However, when dealing with thick metal plates of different materials, optimizing a single value often has limitations in terms of accuracy. For example, when cutting copper and aluminum plates, the plasma densities of the two types of plates are different, and simply adjusting the laser temperature and power cannot achieve high-quality and high-efficiency cutting results. To address this, this method integrates multi-physics field sensing, such as plasma density, local heat flux, and plate thickness, to adjust the laser polarization state, laser power, action time, and healing operation. Adjusting the laser polarization state reflects the optical effect, adjusting the laser power and action time reflects the thermal effect, and the healing operation reflects the force effect. This laser cutting optimization method uses a cross-scale collaborative optical-thermal-mechanical coupling mechanism to control the process, thereby improving the quality and efficiency of laser cutting of thick metal plates.

[0129] Figure 2 The diagram shows a schematic of a laser cutting control optimization system for thick metal plates, which can realize the ideas of this application, according to some embodiments of this application.

[0130] Specifically, a laser cutting control optimization system for thick metal plates includes:

[0131] The acquisition module is used to acquire the thickness parameters, material properties, and thermal diffusivity parameters of the metal plate, and to acquire the plasma density of the metal plate in real time based on the multidimensional parameter set.

[0132] An adjustment module is used to adjust the energy waveform of the thick metal plate based on the multi-dimensional parameter set, and to adjust the laser heat parameters based on the energy waveform time-conditioning.

[0133] The detection module performs detection on the surface of the thick metal plate based on the multidimensional parameter set.

[0134] A healing module that performs a crack healing operation.

[0135] The control module performs joint control optimization for laser cutting of thick metal plates based on polarization state joint adjustment, adjustment of laser thermal parameters, and healing operation.

[0136] The specific usage and function of this embodiment are explained below:

[0137] First, a multi-dimensional parameter set of the thick metal plate is obtained, including the thickness parameter, material properties, and thermal diffusivity parameter. Next, the plasma density of the thick metal plate is acquired in real-time using the multi-dimensional parameter set, and density intervals are defined. The plasma density is compared with these intervals to obtain the comparison results. Based on these results, the laser polarization state is adjusted to obtain the real-time laser transmittance parameter. This polarization state adjustment further modulates the laser transmittance parameter. Then, the energy waveform is time-varying in the thick metal plate using the multi-dimensional parameter set, and the laser thermal parameter is adjusted accordingly. Next, the surface of the thick metal plate is detected using the multi-dimensional parameter set. If cracks are found, crack depth and crack propagation rate parameters are acquired. The local minimum heat flux density is obtained using these parameters, and the real-time local heat flux density is acquired. Based on the local minimum heat flux density and the real-time local heat flux density, a crack healing operation is performed. Finally, the laser cutting of the thick metal plate is jointly controlled and optimized by adjusting the laser transmittance parameter, adjusting the laser thermal parameter, and performing the healing operation.

[0138] The laser transmittance is adjusted by obtaining the plasma density of the thick metal plate, the laser thermal parameters are adjusted by time-varying the energy waveform of the thick metal plate, and the cracks in the thick metal plate are healed by the local minimum heat flux density and the real-time local heat flux density. The joint control optimization is achieved by analyzing the multi-dimensional parameters of the laser and repairing the cracks in the thick metal plate. This embodiment adopts a laser cutting optimization method that integrates multi-physics field perception and cross-scale collaborative control. Through the optical-thermal-mechanical coupling mechanism, the laser cutting quality and efficiency of thick metal plates are improved.

[0139] Furthermore, embodiments of the present invention also provide an electronic device, comprising:

[0140] At least one processor; and at least one memory communicatively connected to the processor; wherein the memory stores instructions executable by at least one processor, the instructions being executed by at least one processor to enable at least one processor to perform the method proposed in Embodiment 1 of the present invention.

[0141] The following is a detailed introduction to the various components of the electronic device:

[0142] In this context, the processor is the control center of the electronic device. It can be a single processor or a collective term for multiple processing elements. For example, a processor can be one or more central processing units (CPUs), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement Embodiment 1 of the present invention, such as one or more digital signal processors (DSPs) or one or more field-programmable gate arrays (FPGAs).

[0143] The processor can perform various functions of the electronic device by running or executing software programs stored in memory and by calling parameters stored in memory.

[0144] The memory is used to store the software program that executes the solution of the present invention, and the execution is controlled by the processor. For specific implementation methods, please refer to the above method embodiments, which will not be repeated here.

[0145] The memory can be a real-only memory (ROM) or other type of static storage device capable of storing static information and instructions, a random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only (CD-ROM), or other optical disc storage, optical disk storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code having an instruction or parameter structure and accessible by a computer, but not limited thereto. The memory can be integrated with the processor or exist independently and coupled to the processor through an interface circuit of an electronic device; this embodiment of the invention does not specifically limit this.

[0146] The above embodiments can be implemented, in whole or in part, by software, hardware (such as circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or parameter center to another website, computer, server, or parameter center via limited means (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a parameter storage device such as a server or parameter center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0147] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0148] It should be understood that, in the embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0149] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for optimizing laser cutting control of thick metal plates, characterized in that, The method includes: Obtain a multidimensional parameter set for a thick metal plate, the multidimensional parameter set including the thickness parameter of the thick metal plate, the material properties of the thick metal plate, and the material thermal diffusivity parameter of the thick metal plate; The plasma density of the thick metal plate is obtained in real time based on the multidimensional parameter set, and the polarization state of the laser is jointly adjusted based on the plasma density. The joint adjustment of polarization state includes a primary adjustment of polarization state and a secondary adjustment of polarization state; The plasma density of the thick metal plate is obtained in real time based on the material properties. At the same time, the density range is divided, and the plasma density is compared with the density range to obtain the comparison result. Based on the comparison results, the laser polarization state is adjusted once to obtain the real-time laser transmittance parameter. The laser transmittance parameter is adjusted again based on the polarization state, which includes linear polarization, elliptic polarization, and circular polarization. Based on the multidimensional parameter set, the energy waveform time-conditioning is applied to the metal thick plate, and the laser heat parameters are adjusted based on the energy waveform time-conditioning. The surface of the thick metal plate is detected based on the multi-dimensional parameter set. If cracks are found, a healing operation is performed based on the cracks. This study optimizes the joint control of laser cutting of thick metal plates based on polarization state adjustment, laser thermal parameter regulation, and healing operation.

2. The laser cutting control optimization method for thick metal plates according to claim 1, characterized in that, The primary and secondary adjustments of the polarization state include: A first density threshold and a second density threshold are set, which are used to distinguish polarization states; If the plasma density of the thick metal plate is less than the first density threshold, the laser maintains linear polarization. If the plasma density of the thick metal plate is greater than or equal to the first density threshold and less than or equal to the second density threshold, the laser is switched to elliptic polarization. If the plasma density of the thick metal plate is greater than the second density threshold, the laser will remain circularly polarized. A threshold for the laser transmittance parameter is set, and the polarization state is adjusted a second time based on the real-time laser transmittance parameter and the threshold for the laser transmittance parameter. If the real-time laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold, then maintain the current polarization state; If the real-time laser transmittance parameter is less than the laser transmittance parameter threshold, adjust the polarization ellipticity until the real-time laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold. When the polarization ellipticity is increased, the laser transmittance parameter also increases. Based on the increase in polarization ellipticity, the real-time laser transmittance parameter is increased. The polarization ellipticity is adjusted once every 100 microseconds to obtain the real-time laser transmittance parameter until the laser transmittance parameter is greater than or equal to the laser transmittance parameter threshold.

3. The laser cutting control optimization method for thick metal plates according to claim 1, characterized in that, The energy waveform time-varying control of the thick metal plate based on the multidimensional parameter set, and the adjustment of the laser thermal parameters based on the energy waveform time-varying control, include: The energy waveform timing mechanism includes time waveform modulation and spatial phase modulation; The time waveform modulation adjusts the laser thermal parameters by controlling the time parameters; The spatial phase modulation adjusts the laser thermal parameters by controlling the temperature parameters.

4. The laser cutting control optimization method for thick metal plates according to claim 3, characterized in that, The time waveform modulation includes: The thickness modulation coefficient is obtained based on the thickness parameter, the basic energy amplitude is obtained based on the material properties, and the modulation frequency is obtained based on the thickness parameter and the thickness modulation coefficient. A time modulation model is constructed based on the thickness modulation coefficient, the basic energy amplitude, and the modulation frequency. The laser waveform is then modulated based on the time modulation model.

5. The laser cutting control optimization method for thick metal plates according to claim 3, characterized in that, The spatial phase modulation includes: The laser wavelength is obtained, the refractive index of the metal plate is obtained, and the thickness gradient factor is obtained based on the laser wavelength, the thickness parameter, and the refractive index of the material. The laser cross-sectional coordinates are obtained, and a spatial modulation model is constructed based on the thickness gradient factor and the laser cross-sectional coordinates. The laser is then spatially phase modulated based on the spatial modulation model.

6. The laser cutting control optimization method for thick metal plates according to claim 1, characterized in that, The process of detecting cracks on the surface of a thick metal plate based on the multidimensional parameter set, and performing a crack healing operation based on the cracks, includes: If there are cracks on the surface of a thick metal plate, obtain crack depth parameters and crack propagation rate parameters, obtain the local minimum heat flux density based on crack depth parameters and crack propagation rate parameters, and obtain the real-time local heat flux density. The surface of the thick metal plate includes the surface of the metal and the subsurface of the metal. If the real-time local heat flux density is greater than or equal to the local minimum heat flux density, then the current parameters are maintained and the operation continues. The current parameters include the laser pulse parameters and the laser pulse width parameters. If the real-time local heat flux density is less than the local minimum heat flux density, then the crack is healed.

7. The laser cutting control optimization method for thick metal plates according to claim 6, characterized in that, The healing operation includes: The crack area is obtained, the material absorptivity of the metal plate is obtained, and the laser pulse parameters required to repair the crack are obtained based on the crack area, the material absorptivity of the metal plate, and the local minimum heat flux density. The laser pulse parameters are expressed as the power required to emit the laser. The highest temperature parameter of the laser during cutting is obtained, and the superheat parameter that causes cracks in the thick metal plate is obtained. Based on the highest temperature parameter, the superheat parameter, the crack depth parameter, and the crack propagation rate parameter, the laser pulse width parameter is obtained, and the laser pulse width parameter is represented by the duration of the laser pulse parameter.

8. The laser cutting control optimization method for thick metal plates according to claim 1, characterized in that, The joint control optimization of laser cutting of thick metal plates based on polarization state adjustment, adjustment of laser thermal parameters, and healing operation includes: The laser transmittance parameter is adjusted based on the aforementioned polarization state. The laser pulse parameters and laser pulse width parameters are adjusted based on the healing operation. The control module adjusts the laser transmittance parameters, laser heat parameters, laser pulse parameters, and laser pulse width parameters to jointly optimize the laser cutting of thick metal plates.

9. A laser cutting control optimization system for thick metal plates, used to implement the method described in any one of claims 1-8, characterized in that, include: The acquisition module is used to acquire the thickness parameters, material properties, and thermal diffusivity parameters of the metal plate, and to acquire the plasma density of the metal plate in real time based on the multidimensional parameter set. An adjustment module is used to apply energy waveform time-varying control to the metal plate based on the multi-dimensional parameter set, and to adjust the laser heat parameters based on the energy waveform time-varying control. The detection module detects the surface of the thick metal plate based on the multidimensional parameter set. A healing module, which performs a crack healing operation; The control module performs joint control optimization for laser cutting of thick metal plates based on polarization state joint adjustment, adjustment of laser thermal parameters, and healing operation.

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