Water-jet guided laser regulation and control method for drilling of double-layer composite material

Abstract

The invention belongs to the technical field of laser processing, and particularly relates to a water-jet guided laser regulation and control method for drilling of a double-layer composite material. By adjusting the water film thickness and the cooling strength in real time, the problem that a heat affected zone is too large in traditional laser machining is effectively solved, so that the drilling precision and efficiency of the double-layer composite material are improved, in the machining process, the distribution uniformity of laser energy can be controlled, it is ensured that a consistent heat effect is formed on the surface of the material, and the machining quality is improved. Therefore, the deformation or ablation phenomenon caused by local overheating is reduced, material damage caused by excessive heat input is avoided, meanwhile, by dynamically adjusting the laser power and the pulse width and combining a stable water film formed by water-guided spraying, heat diffusion is effectively restrained, the integrity of the second layer material is protected, and the service life of the second layer material is prolonged. In the machining process of the first layer of material, the area except the target punching area of the second layer of material is prevented from thermal damage, and therefore the purpose of improving the overall machining quality of the double-layer composite material is achieved.

Description

Technical Field

[0001] This invention belongs to the field of laser processing technology, specifically relating to a water-guided laser control method for drilling holes in double-layer composite materials. Background Technology

[0002] With the continuous development of industrial technology, products made of single materials can no longer meet the ever-increasing performance requirements. Due to their excellent comprehensive performance, bilayer composite materials are widely used in aerospace, electronic packaging and precision instruments. However, due to the significant differences in the physical properties of bilayer materials, traditional laser drilling methods are difficult to control heat input precisely. The introduction of water-guided lasers effectively solves the problem of excessive heat-affected zone in traditional laser processing. By guiding and focusing the laser beam through water flow, precise cooling and thermal control of the processing area are achieved.

[0003] While some existing technologies employ water-guided lasers for drilling composite materials, many suffer from insufficient control over thermal diffusion at the composite material interface, leading to thermal damage in non-target areas of the second layer and affecting drilling accuracy and material integrity. Furthermore, when drilling the first layer, a fixed water jet is often used for cooling, making it impossible to control the water film, resulting in low laser energy utilization and excessive cooling of the material surface, thus affecting drilling efficiency and quality. Therefore, this application provides a water-guided laser control method for drilling two-layer composite materials to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a water-guided laser control method for drilling holes in bilayer composite materials. This method can adjust the water film thickness and cooling intensity in real time according to the differences in the physical properties of the bilayer composite materials, thereby controlling the heat input during the laser drilling process, reducing the impact of heat diffusion, and improving drilling accuracy and efficiency.

[0005] The specific technical solution adopted by this invention is as follows: A water-conducting laser modulation method for drilling holes in bilayer composite materials includes: The thermal conductivity and light absorption characteristics of the bilayer composite material to be processed are obtained, and the position of the interface layer of the bilayer composite material is located. The material facing the laser beam is designated as the first layer material, and the material facing away from the laser beam is designated as the second layer material. The laser emission parameters are determined based on the thermal conductivity and light absorption characteristics of the first layer material, so that the laser energy density reaches a preset threshold on the surface of the first layer material. The thermal response signal of the first layer of material under laser irradiation is collected in real time, and the laser power and pulse width are dynamically adjusted according to the thermal response signal to keep the surface temperature of the first layer of material below the melting point. When the thermal response signal indicates that the first layer of material is about to undergo a phase change, a stable water film is formed in the focal region of the laser beam by combining water jetting. The target aperture of the second layer material is obtained, and the laser beam is dynamically focused by a stable water film. At the same time, the interface layer is locally cooled to suppress heat diffusion to areas outside the target aperture of the second layer material, until the drilling process of the double-layer composite material is completed.

[0006] In a preferred embodiment, the steps of obtaining the thermal conductivity and light absorption characteristics of the bilayer composite material to be processed, and locating the interface layer of the bilayer composite material, include: The thermal conductivity variation curve of the bilayer composite material was determined by laser flash method, and the thermal diffusion rate of the bilayer composite material was determined based on the thermal conductivity variation curve. The light absorptivity and reflectivity of the bilayer composite material at different wavelengths were measured using a spectrophotometer. The net absorbed energy density of the surface of the bilayer composite material was calculated by combining the light absorptivity and reflectivity data, and a matrix of light absorption characteristic parameters was constructed. Based on the thermal conductivity variation curve and the light absorption characteristic parameter matrix, the heat transfer path of the bilayer composite material under laser irradiation is determined, and the thermal resistance abrupt change point of the interface layer in the vertical direction is located by a thermal imager, and the three-dimensional spatial coordinates of the interface layer are output.

[0007] In a preferred embodiment, the step of determining the laser emission parameters based on the thermal conductivity and optical absorption characteristics of the first layer material, so that the laser energy density reaches a preset threshold on the surface of the first layer material, includes: Based on the melting point temperature and energy absorption depth of the first layer material, the initial power range of the laser beam when acting on the first layer material is calculated. Based on the relationship between heat diffusion rate and spot radius, the pulse action time window is determined, and the heat is concentrated in the spot action area by adjusting the pulse width. By matching the laser repetition frequency with the processing path spacing, the heat-affected zones between adjacent laser spots do not overlap, forming a processing area with a continuous distribution of non-thermal accumulation effects. Within the non-thermal accumulation effect processing area, based on the phase transition temperature and light absorption characteristics of the first layer material, the peak power of the laser pulse is matched within the initial power range, so that the laser energy density reaches the material removal threshold before the phase transition of the first layer material occurs.

[0008] In a preferred embodiment, the step of calculating the initial power range of the laser beam acting on the first layer material based on the melting point temperature and energy absorption depth of the first layer material includes: The thermal influence depth of the laser-acting region is determined based on the thermal diffusivity of the first layer material and the pulse width parameter. Based on the density, specific heat capacity, and surface reflectivity of the first layer material, calculate the minimum power required for the surface temperature of the first layer material to reach its melting point. By adjusting the pulse width to control the thermal accumulation effect, the actual applied power is made to be lower than the phase transition threshold of the first layer material. Based on the matching relationship between the processing feed rate and the spot size, the maximum power value that satisfies the continuous absence of heat accumulation effect is selected under critical power conditions, and the range between the minimum power value and the maximum power value is used as the initial power adjustment range.

[0009] In a preferred embodiment, the step of dynamically adjusting the laser power and pulse width based on the thermal response signal to maintain the surface temperature of the first layer of material below its melting point includes: A monitoring period is established based on the time when the first layer of material begins to receive laser irradiation. Multiple monitoring nodes are set up during the monitoring period, and the temperature distribution of the first layer of material surface under each monitoring node is collected in real time, and the temperature peak area is marked. Based on a preset temperature threshold range, the actual temperature of the temperature peak area is compared with that of the temperature peak area; If the actual temperature exceeds the upper limit of the threshold, it indicates that the first layer of material is at risk of overheating. The laser power is dynamically reduced according to the current temperature deviation, and the pulse width is shortened simultaneously to suppress the heat accumulation effect. If the actual temperature is lower than the lower threshold, it indicates insufficient energy input. The laser power is dynamically increased based on the current temperature deviation, and the pulse width is extended to enhance energy input.

[0010] In a preferred embodiment, the step of activating the water jetting system to form a stable water film in the laser beam focal region when the thermal response signal indicates that the first layer of material is about to undergo a phase change includes: The temperature gradient distribution on the surface of the first layer material is monitored in real time. When a sudden change in temperature gradient is detected and the preset phase change trigger threshold is reached, the spray angle of the water guide nozzle is adjusted according to the three-dimensional coordinates of the interface layer to form an initial water film that completely covers the phase change region. A continuous monitoring window is constructed, starting from the initial water film formation point; The temperature change rate of the phase change region is collected within the continuous monitoring window, and the stability of the initial water film coverage is determined based on the temperature change rate. If the temperature change rate exceeds the preset fluctuation range, it indicates that the initial water film coverage is uneven. The pressure parameters of the water guide nozzle are dynamically adjusted according to the fluctuation range of the temperature change rate to enhance the uniformity of the water film until the temperature change rate falls back to within the fluctuation range and a stable water film is formed. If the temperature change rate is within the preset fluctuation range, the pressure parameters of the current water guide nozzle will remain unchanged, and the initial water film will be directly confirmed as a stable water film.

[0011] In a preferred embodiment, the step of obtaining the target aperture of the second layer material and dynamically focusing the laser beam through a stable water film includes: Based on the extinction coefficient of the second layer material and the target aperture depth, the refractive compensation of the laser beam in the water film medium is calculated; Adjust the water outlet angle of the water guide nozzle according to the refractive compensation amount so that the water film shape is adapted to the focusing requirements of the laser beam. During the process of the laser beam penetrating the stable water film, the thickness of the water film and the smoothness of the interface are monitored in real time, and the flow parameters of the water guide nozzle are adjusted based on the thickness of the water film and the smoothness of the interface, so that the focused spot of the laser beam is always in the center area of ​​the preset aperture of the second layer material. When a water film rupture or uneven thickness is detected, the pressure compensation mechanism of the water guide nozzle is immediately triggered to restore the integrity of the water film until the laser beam is focused and stably applied to the center area of ​​the preset aperture of the second layer material.

[0012] In a preferred embodiment, the step of locally cooling the interface layer to suppress heat diffusion to areas outside the target pore size of the second layer material includes: Based on the three-dimensional coordinates of the interface layer and the coverage of the stable water film, the safe distance between the cooling coverage area of ​​the water-guided nozzle and the edge of the target aperture is calculated, and a heat diffusion suppression area centered on the target aperture is established based on the safe distance. When the temperature in the heat diffusion suppression area exceeds the preset cooling trigger threshold, the spray flow rate of the water guide nozzle is increased to enhance the local thickness of the stable water film in the heat diffusion suppression area. The temperature change trend of the heat diffusion suppression area is continuously monitored. If the temperature continues to rise and approaches the material thermal damage threshold, the first layer of material is intermittently irradiated with laser until the temperature of the heat diffusion suppression area drops to less than half of the preset cooling trigger threshold, and then continuous laser irradiation is resumed. After the first layer of material is drilled, the second layer of material is drilled synchronously according to the drilling path of the first layer of material, and the second layer of material is drilled according to the drilling process of the first layer of material until the entire double-layer composite material is perforated.

[0013] The present invention also provides a water-guided laser control system for drilling holes in bilayer composite materials, using the above-described water-guided laser control method for drilling holes in bilayer composite materials, comprising: The interface layer positioning module is used to obtain the thermal conductivity and light absorption characteristics of the double-layer composite material to be processed, and to locate the interface layer position of the double-layer composite material. The layering module is used to mark the material facing the laser beam as the first layer material and the material facing away from the laser beam as the second layer material. It also determines the laser emission parameters based on the thermal conductivity and light absorption characteristics of the first layer material, so that the laser energy density reaches a preset threshold on the surface of the first layer material. A single-layer drilling module is used to collect the thermal response signal of the first layer material under laser irradiation in real time, and dynamically adjust the laser power and pulse width according to the thermal response signal to keep the surface temperature of the first layer material below the melting point. The cooling module is used to form a stable water film in the focal region of the laser beam when the thermal response signal indicates that the first layer of material is about to undergo a phase change, in conjunction with a water jetting method. The two-layer drilling module is used to obtain the target aperture of the second layer material. It dynamically focuses the laser beam through a stable water film and locally cools the interface layer to suppress heat diffusion to areas outside the target aperture of the second layer material until the drilling process of the double-layer composite material is completed.

[0014] And, an electronic device, the electronic device comprising: At least one processor; and a memory communicatively connected to the at least one processor; The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the above-described water-guided laser control method for drilling holes in bilayer composite materials.

[0015] The technical effects achieved by this invention are as follows: This invention effectively solves the problem of excessive heat-affected zone in traditional laser processing by adjusting the water film thickness and cooling intensity in real time, thereby improving the accuracy and efficiency of drilling holes in double-layer composite materials. During processing, the uniformity of laser energy distribution is controlled to ensure a consistent thermal effect on the material surface, thereby reducing deformation or ablation caused by local overheating and avoiding material damage caused by excessive heat input. At the same time, by dynamically adjusting the laser power and pulse width, and combining it with the stable water film formed by water jetting, effective suppression of heat diffusion is achieved, protecting the integrity of the second layer material. This ensures that the area outside the target drilling area of ​​the second layer material is not damaged by heat during the processing of the first layer material, thereby improving the overall processing quality of the double-layer composite material. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the method flow of the present invention; Figure 2 This is a schematic diagram of the system modules of the present invention; Figure 3This is a schematic diagram of the electronic device structure of the present invention. Detailed Implementation

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0018] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0019] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in a preferred embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that mutually excludes other embodiments.

[0020] Please see Figure 1 As shown, this invention provides a water-guided laser control method for drilling holes in bilayer composite materials, comprising: S1. Obtain the thermal conductivity and light absorption characteristics of the double-layer composite material to be processed, and locate the interface layer of the double-layer composite material. In step S1, during the drilling process of the bilayer composite material, the difference in thermal conductivity and light absorption characteristics of the materials leads to uneven distribution of laser energy within the material. Therefore, directly performing through-hole drilling of the bilayer will obviously cause differences in the heat-affected zones between the different material layers, resulting in problems such as rough hole walls and interlayer delamination. Therefore, when drilling the bilayer composite material, it is first necessary to collect the thermal conductivity and light absorption characteristics of the bilayer composite material to be processed to establish a mapping relationship between laser energy input and material response. At the same time, the interface layer position of the bilayer composite material is located to provide a spatial reference for the subsequent dynamic control of laser parameters. The steps of acquiring the thermal conductivity and light absorption characteristics of the bilayer composite material to be processed and locating the interface layer position of the bilayer composite material include: The thermal conductivity variation curve of the bilayer composite material was determined by laser flash method, and the thermal diffusion rate of the bilayer composite material was determined based on the thermal conductivity variation curve. The light absorptivity and reflectivity of the bilayer composite material at different wavelengths were measured using a spectrophotometer. The net absorbed energy density of the surface of the bilayer composite material was calculated by combining the light absorptivity and reflectivity data, and a matrix of light absorption characteristic parameters was constructed. Based on the thermal conductivity variation curve and the light absorption characteristic parameter matrix, the heat transfer path of the bilayer composite material under laser irradiation is determined, and the thermal resistance abrupt change point of the interface layer in the vertical direction is located by a thermal imager, and the three-dimensional spatial coordinates of the interface layer are output. Specifically, when obtaining the thermal conductivity and light absorption characteristics of the bilayer composite material to be processed, the material must first be pretreated to ensure the accuracy of the test results. Pretreatment steps include cleaning the material surface, removing surface defects, and ensuring the flatness and uniformity of the material. After pretreatment, the thermal conductivity variation curve of the bilayer composite material is determined using the laser flash method. The laser flash method is based on the principle of thermal diffusion; it calculates the thermal conductivity by instantaneously heating the material and measuring the temperature change over time. This is a conventional testing method well-known to those skilled in the art. By obtaining the thermal conductivity variation curve, the thermal conductivity of the bilayer composite material in different temperature ranges can be clearly identified. Correspondingly, the difference in thermal diffusion rate between the layers of the bilayer composite material during laser irradiation can be output. Then, a spectrophotometer is used to measure the light absorption of the bilayer composite material at different wavelengths. Spectrophotometers can emit light of different wavelengths and measure the absorption and reflection of these wavelengths by materials. Based on this, a light absorption characteristic parameter matrix of the material can be constructed. The light absorption characteristic parameter matrix describes the light absorption and reflection characteristics of the material at different wavelengths. After obtaining the thermal conductivity and light absorption characteristics, it is also necessary to determine the heat transfer path of the bilayer composite material under laser irradiation. Specifically, simulation tests can be conducted using thermal simulation software or experimental testing to determine the path and attenuation law of heat conduction from the surface to the interior of the bilayer composite material during laser irradiation. On this basis, a thermal imager can be used to monitor the temperature distribution changes of the bilayer composite material in real time during laser irradiation and identify the regions of abrupt changes in thermal resistance in the vertical direction. This effectively locates the three-dimensional spatial coordinates of the interface layer, realizing the identification and positioning of the interface layer of the bilayer composite material.

[0021] S2. The material facing the laser beam is marked as the first layer material, and the material facing away from the laser beam is marked as the second layer material. The laser emission parameters are determined based on the thermal conductivity and light absorption characteristics of the first layer material, so that the laser energy density reaches a preset threshold on the surface of the first layer material. In step S2, during actual drilling operations, the material facing the laser beam is defined as the first layer material, while the material facing away from the laser beam is designated as the second layer material. Since the first layer material directly receives laser energy, its thermal conductivity and optical absorption characteristics directly affect the energy distribution and conduction efficiency. Therefore, it is necessary to optimize the laser emission parameters, including power density, pulse width, and frequency, based on the characteristics of this layer material to avoid processing defects or reduced efficiency due to excessive or insufficient energy. The step of determining the laser emission parameters based on the thermal conductivity and optical absorption characteristics of the first layer material to ensure that the laser energy density reaches a preset threshold on the surface of the first layer material includes: Based on the melting point temperature and energy absorption depth of the first layer material, the initial power range of the laser beam when acting on the first layer material is calculated. Based on the relationship between heat diffusion rate and spot radius, the pulse action time window is determined, and the heat is concentrated in the spot action area by adjusting the pulse width. By matching the laser repetition frequency with the processing path spacing, the heat-affected zones between adjacent laser spots do not overlap, forming a processing area with a continuous distribution of non-thermal accumulation effects. Within the non-thermal accumulation effect processing area, based on the phase transition temperature and light absorption characteristics of the first layer material, the peak power of the laser pulse is matched within the initial power range so that the laser energy density reaches the material removal threshold before the phase transition of the first layer material occurs. Specifically, when drilling the first layer of material, the energy density required for the laser beam to reach the preset processing depth on the surface of the first layer of material needs to be calculated based on the melting point and energy absorption characteristics of the first layer of material. This ensures the formation of a stable heat-affected zone on the surface of the first layer of material, while avoiding excessive heat accumulation due to excessive energy or incomplete processing due to insufficient energy. Then, using the pre-established mapping relationship between laser parameters and material response (this mapping relationship is specifically constructed based on a database built by combining experimental data and simulation models), the power density, pulse width, and frequency of the laser beam are dynamically adjusted to control the distribution of laser energy within the first layer of material. Under the action of the laser beam, the temperature of the surface of the first layer of material rises rapidly, but due to the control of the pulse width, the heat is confined within the area of ​​the laser spot, avoiding excessive heat diffusion. As the laser beam moves, the heat-affected zones formed between adjacent laser spots maintain a certain distance, avoiding overlap of the heat-affected zones, thereby ensuring the continuity and uniformity of the processing area. During the processing, the thermal response signal of the first layer of material is monitored in real time, and the laser parameters are dynamically adjusted according to the signal changes to ensure the stability of the processing process.

[0022] It should be noted that the steps for calculating the initial power range of the laser beam acting on the first layer of material, based on the melting point temperature and energy absorption depth of the first layer, include: The thermal influence depth of the laser-acting region is determined based on the thermal diffusivity of the first layer material and the pulse width parameter. Based on the density, specific heat capacity, and surface reflectivity of the first layer material, calculate the minimum power required for the surface temperature of the first layer material to reach its melting point. By adjusting the pulse width to control the thermal accumulation effect, the actual applied power is made to be lower than the phase transition threshold of the first layer material. Based on the matching relationship between the processing feed rate and the spot size, the maximum power value that satisfies the continuous absence of heat accumulation effect is selected under the critical power condition, and the range between the minimum power value and the maximum power value is taken as the initial power adjustment range. When determining the initial power range, the influence of the thermal diffusivity of the first layer material and the pulse width parameter on the heat-affected depth (HAD) of the laser-affected region must first be considered. The thermal diffusivity determines the speed of heat propagation within the material, while the pulse width determines the duration of heat application. Together, they determine the HAD of the laser-affected region. By calculating the HAD, it can be ensured that the laser energy is reasonably distributed within the first layer material, preventing excessive heat accumulation due to excessive energy and incomplete processing due to insufficient energy. The HAD is calculated as follows: HAD = ... In the formula, Indicates the thermal diffusivity. The pulse width is represented by the pulse width. Then, combined with the density, specific heat capacity, and surface reflectivity of the first layer material, the minimum power required to bring the surface temperature of the first layer material to its melting point is calculated. Minimum power value = In the formula, Indicates the density of the material. Indicates specific heat capacity. This indicates the melting point temperature of the first layer of material. Indicates the initial ambient temperature. Indicates the depth of heat effect. Indicates the area affected by the laser. This represents the surface reflectivity of the first layer of material. This represents the laser energy coupling efficiency, ensuring that the laser energy forms a stable heat-affected zone on the surface of the first layer of material. The material density and specific heat capacity determine the material's ability to absorb heat, while the surface reflectivity affects the absorption efficiency of laser energy on the material surface. After determining the minimum power value, the heat accumulation effect is controlled by adjusting the pulse width. By adjusting the pulse width, the actual applied power can always be kept below the phase transition threshold of the first layer of material, thereby avoiding unnecessary phase transitions. At the same time, based on the matching relationship between the processing feed rate and the spot size (this matching relationship is determined by the correspondence between the spot movement speed and the interaction time on the material surface), the maximum power value that satisfies the condition of continuous no heat accumulation effect is selected under the critical power condition. Finally, the interval between the minimum power value and the maximum power value is used as the initial power adjustment range. Specifically, it can be dynamically adjusted in subsequent processing based on the real-time monitored thermal response signal to ensure the stability and efficiency of the processing process.

[0023] S3. Real-time acquisition of the thermal response signal of the first layer material under laser irradiation, and dynamic adjustment of laser power and pulse width according to the thermal response signal to keep the surface temperature of the first layer material below the melting point; In step S3, during the drilling process of the first layer of material, it is necessary to monitor the surface temperature change of the material in real time. A thermal response signal is collected using an infrared sensor, and the collected temperature value is compared with a preset melting point threshold. When the temperature approaches the melting point, the laser power is automatically reduced or the pulse width is shortened to suppress the heat accumulation effect. The step of dynamically adjusting the laser power and pulse width based on the thermal response signal to maintain the surface temperature of the first layer of material below the melting point includes: A monitoring period is established based on the time when the first layer of material begins to receive laser irradiation. Multiple monitoring nodes are set up during the monitoring period, and the temperature distribution of the first layer of material surface under each monitoring node is collected in real time, and the temperature peak area is marked. Based on a preset temperature threshold range, the actual temperature of the temperature peak area is compared with that of the temperature peak area; If the actual temperature exceeds the upper limit of the threshold, it indicates that the first layer of material is at risk of overheating. The laser power is dynamically reduced according to the current temperature deviation, and the pulse width is shortened simultaneously to suppress the heat accumulation effect. If the actual temperature is lower than the lower threshold, it indicates insufficient energy input. The laser power is dynamically increased and the pulse width is extended to enhance the energy input based on the current temperature deviation. Specifically, when optimizing the temperature during the drilling process of the first layer of material, a monitoring period is defined starting from the moment the first layer of material begins to receive laser irradiation. This monitoring period covers the entire laser drilling process, and multiple time nodes are set as monitoring points within this period. At each monitoring point, the temperature distribution on the surface of the first layer of material is captured in real time, and the area reaching the peak temperature is marked. Then, based on a preset temperature threshold range (which is set based on the thermophysical properties of the first layer of material and the expected processing effect), the real-time temperature peak is compared with the preset threshold range during actual processing. If the actual temperature exceeds the upper limit of the temperature threshold range, it indicates that the first layer of material is at risk of overheating. In this case, the laser power is dynamically reduced and the pulse width is shortened simultaneously based on the current temperature deviation to effectively suppress excessive heat accumulation. The control process can use proportional adjustment or proportional-integral adjustment, and the appropriate adjustment method can be selected according to the actual processing requirements. If the actual temperature is lower than the lower limit of the temperature threshold range, it indicates that the laser energy input is insufficient. In this case, the laser power is increased accordingly and the pulse width is extended to ensure sufficient energy input to the material.

[0024] S4. When the thermal response signal indicates that the first layer of material is about to undergo a phase change, a stable water film is formed in the focal region of the laser beam by combining water jetting. In step S4, during temperature control, if the thermal response signal indicates that the first layer of material is about to reach its phase transition temperature, it means that the internal structure of the material is about to undergo a sudden change. At this time, cooling measures need to be taken in time to avoid the adverse effects of the phase transition. Specifically, a stable water film is quickly formed in the laser beam focal region by a water-guided jet device. The water film can effectively absorb and remove heat from the material surface, thereby reducing the local temperature and preventing the material from undergoing a phase transition due to overheating. The step of activating the water-guided jet system to form a stable water film in the laser beam focal region when the thermal response signal indicates that the first layer of material is about to undergo a phase transition includes: The temperature gradient distribution on the surface of the first layer material is monitored in real time. When a sudden change in temperature gradient is detected and the preset phase change trigger threshold is reached, the spray angle of the water guide nozzle is adjusted according to the three-dimensional coordinates of the interface layer to form an initial water film that completely covers the phase change region. A continuous monitoring window is constructed, starting from the initial water film formation point; The temperature change rate of the phase change region is collected within the continuous monitoring window, and the stability of the initial water film coverage is determined based on the temperature change rate. If the temperature change rate exceeds the preset fluctuation range, it indicates that the initial water film coverage is uneven. The pressure parameters of the water guide nozzle are dynamically adjusted according to the fluctuation range of the temperature change rate to enhance the uniformity of the water film until the temperature change rate falls back to within the fluctuation range and a stable water film is formed. If the temperature change rate is within the preset fluctuation range, the pressure parameters of the current water guide nozzle will remain unchanged, and the initial water film will be directly confirmed as a stable water film. Specifically, in establishing a stable water film, the first step is to monitor the temperature gradient change on the surface of the first layer of material in real time. When the temperature gradient changes abruptly and reaches a preset phase change trigger threshold, it indicates that the first layer of material is about to enter the phase change stage. At this point, the water jetting device adjusts the jetting angle of the water jet nozzles according to the previously determined three-dimensional coordinates of the interface layer, ensuring that the water film accurately covers the area where the phase change is about to occur, forming an initial water film. This initial water film quickly absorbs and removes heat from the surface of the first layer of material, thereby reducing the local temperature and preventing unnecessary phase changes due to overheating, which could affect processing quality. Next, starting from the moment the initial water film forms, a continuous monitoring window is established. Within this window, the temperature change rate of the phase change region is continuously collected. By analyzing the temperature change rate, it can be determined whether the initial water film coverage is stable. If the temperature change rate exceeds the preset fluctuation range (the allowable fluctuation under the premise that the temperature fluctuation does not exceed the phase change temperature), it means that the initial water film coverage is not uniform enough, and there may be local overheating or undercooling. At this time, it is necessary to dynamically adjust the pressure parameters of the water guide nozzle according to the fluctuation range of the temperature change rate. By increasing or decreasing the injection pressure, the uniformity of the water film can be improved until the temperature change rate falls back to within the preset fluctuation range, and it is determined to be a stable water film that can continuously play a cooling role. If the temperature change rate is always within the preset fluctuation range, it indicates that the initial water film coverage is uniform and effective, and the initial water film can be directly confirmed as a stable water film without further adjustment.

[0025] S5. Obtain the target aperture of the second layer material, dynamically focus the laser beam through a stable water film, and simultaneously cool the interface layer locally to suppress heat diffusion to areas outside the target aperture of the second layer material until the drilling process of the double-layer composite material is completed. In step S5, during the stable drilling process of the first layer material, it is also necessary to monitor the second layer material in real time to prevent the drilling temperature of the first layer material from affecting the structural integrity of the second layer material. The steps of obtaining the target aperture of the second layer material and dynamically focusing the laser beam through a stable water film include: Based on the extinction coefficient of the second layer material and the target aperture depth, the refractive compensation of the laser beam in the water film medium is calculated; Adjust the water outlet angle of the water guide nozzle according to the refractive compensation amount so that the water film shape is adapted to the focusing requirements of the laser beam. During the process of the laser beam penetrating the stable water film, the thickness of the water film and the smoothness of the interface are monitored in real time, and the flow parameters of the water guide nozzle are adjusted based on the thickness of the water film and the smoothness of the interface, so that the focused spot of the laser beam is always in the center area of ​​the preset aperture of the second layer material. When a water film rupture or uneven thickness is detected, the pressure compensation mechanism of the water guide nozzle is immediately triggered to restore the integrity of the water film until the laser beam is focused and stably acts on the preset aperture center area of ​​the second layer material. Specifically, during the monitoring of the second layer material, the target aperture size and expected processing depth of the second layer material are collected. Based on the extinction coefficient of the second layer material (which reflects the material's ability to absorb laser energy) and the target aperture depth, the refractive compensation required for the laser beam to penetrate the water film medium can be calculated (refractive compensation = (extinction coefficient × target aperture depth) / water film refractive index). This ensures that the laser beam can be accurately focused on the predetermined position of the second layer material. Then, based on the refractive compensation, the water outlet angle of the water guide nozzle is adjusted accordingly so that the shape of the water film can adapt to the focusing requirements of the laser beam, ensuring optimal focusing effect. During the process of the laser beam penetrating the stable water film, the refractive compensation is calculated. The system continuously monitors the thickness of the water film and the smoothness of the interface layer. If any change in the water film thickness or unevenness of the interface layer is detected, the flow rate parameters of the water guide nozzle will be adjusted immediately. By increasing or decreasing the water flow rate, the thickness of the water film and the smoothness of the interface layer will be maintained, ensuring that the focused spot of the laser beam can always be stably located in the center area of ​​the preset aperture of the second layer material. If a rupture or uneven thickness distribution of the water film is detected, the pressure compensation mechanism of the water guide nozzle will be triggered immediately. By adjusting the injection pressure, the integrity of the water film will be quickly restored, ensuring that the laser beam can continue to be focused and stably act on the center area of ​​the preset aperture of the second layer material without interference, until the entire drilling process of the double-layer composite material is successfully completed.

[0026] In addition, the step of locally cooling the interface layer to suppress heat diffusion to areas outside the target pore size of the second layer material includes: Based on the three-dimensional coordinates of the interface layer and the coverage of the stable water film, the safe distance between the cooling coverage area of ​​the water-guided nozzle and the edge of the target aperture is calculated, and a heat diffusion suppression area centered on the target aperture is established based on the safe distance. When the temperature in the heat diffusion suppression area exceeds the preset cooling trigger threshold, the spray flow rate of the water guide nozzle is increased to enhance the local thickness of the stable water film in the heat diffusion suppression area. The temperature change trend of the heat diffusion suppression area is continuously monitored. If the temperature continues to rise and approaches the material thermal damage threshold, the first layer of material is intermittently irradiated with laser until the temperature of the heat diffusion suppression area drops to less than half of the preset cooling trigger threshold, and then continuous laser irradiation is resumed. In this process, after the first layer of material is drilled, the second layer of material is drilled synchronously according to the drilling path of the first layer of material, and the second layer of material is drilled according to the drilling process of the first layer of material until the entire double-layer composite material is perforated. Specifically, in the process of suppressing thermal diffusion, the cooling coverage area of ​​the water-guided nozzle is first determined based on the three-dimensional coordinates of the interface layer and the coverage range of the stable water film. The safe distance between this area and the edge of the target aperture in the second layer material is then calculated: safe distance = water film coverage radius / (material thermal conductivity × laser power coefficient). The purpose of setting the safe distance is to ensure that the cooling effect of the water film does not affect the performance of the material at the edge of the target aperture during the cooling process. Based on the safe distance, a thermal diffusion suppression region centered on the target aperture is established. When the temperature within the thermal diffusion suppression region exceeds a preset cooling trigger threshold, it indicates that the accumulated heat within the thermal diffusion suppression region has reached the target value requiring cooling. At this point, the jet flow rate of the water-guided nozzle is increased to enhance the local thickness of the stable water film within the thermal diffusion suppression region, thereby improving cooling efficiency. To enhance cooling, the system continuously monitors the temperature trend within the heat diffusion suppression area. If the temperature continues to rise and approaches the material's thermal damage threshold, intermittent laser irradiation is applied to the first layer of material. This reduces heat input by briefly stopping laser irradiation without affecting the drilling progress, allowing the second layer of material time to dissipate heat. Continuous laser irradiation is then resumed once the temperature within the heat diffusion suppression area drops below half of the preset cooling trigger threshold, and the drilling process continues. Furthermore, after the first layer of material is drilled, the drilling of the second layer is synchronized with the drilling path of the first layer, ensuring that the drilling positions of the two layers are consistent. Then, based on the drilling process of the first layer, the second layer continues to be drilled until the entire double-layer composite material is perforated.

[0027] Please see Figure 2 A water-guided laser control system for drilling holes in bilayer composite materials, using the aforementioned water-guided laser control method for drilling holes in bilayer composite materials, includes: The interface layer positioning module is used to obtain the thermal conductivity and light absorption characteristics of the double-layer composite material to be processed, and to locate the interface layer position of the double-layer composite material. The layering module is used to mark the material facing the laser beam as the first layer material and the material facing away from the laser beam as the second layer material. It also determines the laser emission parameters based on the thermal conductivity and light absorption characteristics of the first layer material, so that the laser energy density reaches a preset threshold on the surface of the first layer material. A single-layer drilling module is used to collect the thermal response signal of the first layer material under laser irradiation in real time, and dynamically adjust the laser power and pulse width according to the thermal response signal to keep the surface temperature of the first layer material below the melting point. The cooling module is used to form a stable water film in the focal region of the laser beam when the thermal response signal indicates that the first layer of material is about to undergo a phase change, in conjunction with a water jetting method. The two-layer drilling module is used to obtain the target aperture of the second layer material. It dynamically focuses the laser beam through a stable water film and locally cools the interface layer to suppress heat diffusion to areas outside the target aperture of the second layer material until the drilling process of the double-layer composite material is completed. The execution process of the above-mentioned control system corresponds to the execution process of the water-guided laser control method used for drilling holes in bilayer composite materials, and will not be repeated here.

[0028] Please see Figure 3 An electronic device, comprising: At least one processor; and memory that is communicatively connected to at least one processor; The memory stores a computer program that can be executed by at least one processor, which enables the at least one processor to execute the above-described water-guided laser control method for drilling holes in bilayer composite materials.

[0029] The processor of the aforementioned electronic device can be a central processing unit (CPU), a graphics processing unit (GPU), or a digital signal processor (DSP), etc. The memory can include high-speed random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. The electronic device may also include an arithmetic unit, input devices, and output devices. The arithmetic unit is responsible for executing algorithm instructions in the computer program, the input devices are used to receive external control instructions or data input, and the output devices are used to visualize the processing results or transmit them to an external system.

[0030] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0031] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A water-guided laser control method for drilling holes in bilayer composite materials, characterized in that: include: The thermal conductivity and light absorption characteristics of the bilayer composite material to be processed are obtained, and the position of the interface layer of the bilayer composite material is located. The material facing the laser beam is designated as the first layer material, and the material facing away from the laser beam is designated as the second layer material. The laser emission parameters are determined based on the thermal conductivity and light absorption characteristics of the first layer material, so that the laser energy density reaches a preset threshold on the surface of the first layer material. The thermal response signal of the first layer of material under laser irradiation is collected in real time, and the laser power and pulse width are dynamically adjusted according to the thermal response signal to keep the surface temperature of the first layer of material below the melting point. When the thermal response signal indicates that the first layer of material is about to undergo a phase change, a stable water film is formed in the focal region of the laser beam by combining water jetting. The target aperture of the second layer material is obtained, and the laser beam is dynamically focused by a stable water film. At the same time, the interface layer is locally cooled to suppress heat diffusion to areas outside the target aperture of the second layer material, until the drilling process of the double-layer composite material is completed.

2. The water-guided laser control method for drilling holes in bilayer composite materials according to claim 1, characterized in that: The steps of obtaining the thermal conductivity and light absorption characteristics of the bilayer composite material to be processed, and locating the interface layer of the bilayer composite material, include: The thermal conductivity variation curve of the bilayer composite material was determined by laser flash method, and the thermal diffusion rate of the bilayer composite material was determined based on the thermal conductivity variation curve. The light absorptivity and reflectivity of the bilayer composite material at different wavelengths were measured using a spectrophotometer. The net absorbed energy density of the surface of the bilayer composite material was calculated by combining the light absorptivity and reflectivity data, and a matrix of light absorption characteristic parameters was constructed. Based on the thermal conductivity variation curve and the light absorption characteristic parameter matrix, the heat transfer path of the bilayer composite material under laser irradiation is determined, and the thermal resistance abrupt change point of the interface layer in the vertical direction is located by a thermal imager, and the three-dimensional spatial coordinates of the interface layer are output.

3. The water-guided laser control method for drilling holes in bilayer composite materials according to claim 1, characterized in that: The step of determining the laser emission parameters based on the thermal conductivity and light absorption characteristics of the first layer material, so that the laser energy density reaches a preset threshold on the surface of the first layer material, includes: Based on the melting point temperature and energy absorption depth of the first layer material, the initial power range of the laser beam when acting on the first layer material is calculated. Based on the relationship between heat diffusion rate and spot radius, the pulse action time window is determined, and the heat is concentrated in the spot action area by adjusting the pulse width. By matching the laser repetition frequency with the processing path spacing, the heat-affected zones between adjacent laser spots do not overlap, forming a processing area with a continuous distribution of non-thermal accumulation effects. Within the non-thermal accumulation effect processing area, based on the phase transition temperature and light absorption characteristics of the first layer material, the peak power of the laser pulse is matched within the initial power range, so that the laser energy density reaches the material removal threshold before the phase transition of the first layer material occurs.

4. The water-guided laser control method for drilling holes in bilayer composite materials according to claim 1, characterized in that: The step of calculating the initial power range of the laser beam acting on the first layer of material based on the melting point temperature and energy absorption depth of the first layer material includes: The thermal influence depth of the laser-acting region is determined based on the thermal diffusivity of the first layer material and the pulse width parameter. Based on the density, specific heat capacity, and surface reflectivity of the first layer material, calculate the minimum power required for the surface temperature of the first layer material to reach its melting point. By adjusting the pulse width to control the thermal accumulation effect, the actual applied power is made to be lower than the phase transition threshold of the first layer material. Based on the matching relationship between the processing feed rate and the spot size, the maximum power value that satisfies the continuous absence of heat accumulation effect is selected under critical power conditions, and the range between the minimum power value and the maximum power value is used as the initial power adjustment range.

5. The water-guided laser control method for drilling holes in bilayer composite materials according to claim 1, characterized in that: The step of dynamically adjusting the laser power and pulse width based on the thermal response signal to maintain the surface temperature of the first layer of material below its melting point includes: A monitoring period is established based on the time when the first layer of material begins to receive laser irradiation. Multiple monitoring nodes are set up during the monitoring period, and the temperature distribution of the first layer of material surface under each monitoring node is collected in real time, and the temperature peak area is marked. Based on a preset temperature threshold range, the actual temperature of the temperature peak area is compared with that of the temperature peak area; If the actual temperature exceeds the upper limit of the threshold, it indicates that the first layer of material is at risk of overheating. The laser power is dynamically reduced according to the current temperature deviation, and the pulse width is shortened simultaneously to suppress the heat accumulation effect. If the actual temperature is lower than the lower threshold, it indicates insufficient energy input. The laser power is dynamically increased based on the current temperature deviation, and the pulse width is extended to enhance energy input.

6. The water-guided laser control method for drilling holes in bilayer composite materials according to claim 1, characterized in that: The step of activating the water jetting system to form a stable water film in the laser beam focal region when the thermal response signal indicates that the first layer of material is about to undergo a phase change includes: The temperature gradient distribution on the surface of the first layer material is monitored in real time. When a sudden change in temperature gradient is detected and the preset phase change trigger threshold is reached, the spray angle of the water guide nozzle is adjusted according to the three-dimensional coordinates of the interface layer to form an initial water film that completely covers the phase change region. A continuous monitoring window is constructed, starting from the initial water film formation point; The temperature change rate of the phase change region is collected within the continuous monitoring window, and the stability of the initial water film coverage is determined based on the temperature change rate. If the temperature change rate exceeds the preset fluctuation range, it indicates that the initial water film coverage is uneven. The pressure parameters of the water guide nozzle are dynamically adjusted according to the fluctuation range of the temperature change rate to enhance the uniformity of the water film until the temperature change rate falls back to within the fluctuation range and a stable water film is formed. If the temperature change rate is within the preset fluctuation range, the pressure parameters of the current water guide nozzle will remain unchanged, and the initial water film will be directly confirmed as a stable water film.

7. The water-guided laser control method for drilling holes in bilayer composite materials according to claim 1, characterized in that: The steps of obtaining the target aperture of the second layer material and dynamically focusing the laser beam through a stable water film include: Based on the extinction coefficient of the second layer material and the target aperture depth, the refractive compensation of the laser beam in the water film medium is calculated; Adjust the water outlet angle of the water guide nozzle according to the refractive compensation amount so that the water film shape is adapted to the focusing requirements of the laser beam. During the process of the laser beam penetrating the stable water film, the thickness of the water film and the smoothness of the interface are monitored in real time, and the flow parameters of the water guide nozzle are adjusted based on the thickness of the water film and the smoothness of the interface, so that the focused spot of the laser beam is always in the center area of ​​the preset aperture of the second layer material. When a water film rupture or uneven thickness is detected, the pressure compensation mechanism of the water guide nozzle is immediately triggered to restore the integrity of the water film until the laser beam is focused and stably applied to the center area of ​​the preset aperture of the second layer material.

8. A water-guided laser control method for drilling holes in bilayer composite materials according to claim 1, characterized in that: The step of locally cooling the interface layer to suppress heat diffusion to areas outside the target pore size of the second layer material includes: Based on the three-dimensional coordinates of the interface layer and the coverage of the stable water film, the safe distance between the cooling coverage area of ​​the water-guided nozzle and the edge of the target aperture is calculated, and a heat diffusion suppression area centered on the target aperture is established based on the safe distance. When the temperature in the heat diffusion suppression area exceeds the preset cooling trigger threshold, the spray flow rate of the water guide nozzle is increased to enhance the local thickness of the stable water film in the heat diffusion suppression area. The temperature change trend of the heat diffusion suppression area is continuously monitored. If the temperature continues to rise and approaches the material thermal damage threshold, the first layer of material is intermittently irradiated with laser until the temperature of the heat diffusion suppression area drops to less than half of the preset cooling trigger threshold, and then continuous laser irradiation is resumed. After the first layer of material is drilled, the second layer of material is drilled synchronously according to the drilling path of the first layer of material, and the second layer of material is drilled according to the drilling process of the first layer of material until the entire double-layer composite material is perforated.

9. A water-guided laser control system for drilling holes in double-layer composite materials, characterized in that: The water-guided laser control method for drilling holes in bilayer composite materials according to any one of claims 1 to 8 includes: The interface layer positioning module is used to obtain the thermal conductivity and light absorption characteristics of the double-layer composite material to be processed, and to locate the interface layer position of the double-layer composite material. The layering module is used to mark the material facing the laser beam as the first layer material and the material facing away from the laser beam as the second layer material. It also determines the laser emission parameters based on the thermal conductivity and light absorption characteristics of the first layer material, so that the laser energy density reaches a preset threshold on the surface of the first layer material. A single-layer drilling module is used to collect the thermal response signal of the first layer material under laser irradiation in real time, and dynamically adjust the laser power and pulse width according to the thermal response signal to keep the surface temperature of the first layer material below the melting point. The cooling module is used to form a stable water film in the focal region of the laser beam when the thermal response signal indicates that the first layer of material is about to undergo a phase change, in conjunction with a water jetting method. The two-layer drilling module is used to obtain the target aperture of the second layer material. It dynamically focuses the laser beam through a stable water film and locally cools the interface layer to suppress heat diffusion to areas outside the target aperture of the second layer material until the drilling process of the double-layer composite material is completed.

10. An electronic device, characterized in that: The electronic device includes: At least one processor; and a memory communicatively connected to the at least one processor; The memory stores a computer program that can be executed by the at least one processor, which is then executed by the at least one processor to enable the at least one processor to perform the water-guided laser control method for drilling holes in bilayer composite materials as described in any one of claims 1 to 9.

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