Laser cleaning method based on coupling effect of different cleaning mechanisms

Abstract

The invention provides a laser cleaning method based on coupling effects of different cleaning mechanisms. According to the method, plasma shock wave effect, vaporization effect, thermal stress, evaporation pressure, photon pressure and cold ablation are considered, and under the coupling effect of six laser cleaning mechanisms, dirt on the surface of the substrate is cleaned through laser. Secondly, the problem that the dynamic characteristics of laser cleaning cannot be truly reflected due to the fact that only single mechanism research and process research in the laser cleaning process are considered in previous research is solved. The coupling effect of various laser cleaning mechanisms is considered, so that surface dirt is efficiently removed by laser without damaging the surface of a substrate. On the basis, the laser cleaning method based on the coupling effect of different cleaning mechanisms can more accurately reflect the actual process of laser cleaning of the to-be-cleaned material, and it is guaranteed that the substrate material is not damaged.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser cleaning, and in particular relates to a laser cleaning method based on the coupling effect of different cleaning mechanisms. Background Art

[0002] Laser cleaning technology offers advantages such as excellent cleaning results, wide application range, high precision, non-contact operation, and good accessibility. This technology can be used to clean parts that are difficult to handle with traditional methods, significantly improving product cleaning efficiency and reliability.

[0003] Currently, research into the mechanisms of laser cleaning is still in its exploratory stages, with limited research on cleaning technologies based on different laser cleaning mechanisms. Because laser cleaning involves multiple mechanisms, determining the optimal cleaning depth for different materials based on different laser cleaning mechanisms and developing laser cleaning methods based on these mechanisms are urgent challenges.

[0004] Previous studies have focused solely on the mechanism and process of laser cleaning, an approach that fails to truly reflect the dynamic characteristics of laser cleaning. These studies also overlooked the multiple mechanisms at work during laser cleaning, making it difficult to accurately determine the optimal depth at which laser cleaning can clean contaminated surfaces.

[0005] Furthermore, the laser cleaning process involves the following: plasma shock wave effects, vaporization effects, thermal stress, evaporation pressure, photon pressure, and cold ablation (breaking molecular bonds). These six laser cleaning mechanisms work together and have been simplified or overlooked in previous research. Traditional consideration of a single laser cleaning mechanism fails to truly reflect the interaction characteristics between the laser and contaminants, making it difficult to achieve laser removal of surface contaminants without damaging the substrate surface. Therefore, how to consider the coupling of multiple laser cleaning mechanisms to efficiently and accurately develop laser cleaning methods is an important issue that needs to be addressed. Summary of the Invention

[0006] The purpose of the present invention is to address the problems existing in the prior art, such as "considering a single laser cleaning mechanism" and ignoring the coupling effects of six laser cleaning mechanisms: plasma shock wave effect, vaporization effect, thermal stress, evaporation pressure, photon pressure and cold ablation (breaking molecular bonds). A laser cleaning method based on the coupling effects of different cleaning mechanisms is proposed.

[0007] The present invention is achieved through the following technical solutions. The present invention proposes a laser cleaning method based on the coupling of different cleaning mechanisms, the method comprising:

[0008] Step 1: Clean the material to be cleaned based on the plasma shock wave effect mechanism to achieve a removal depth of L1. In step 1, define the thermal and physical properties of the material; clarify the parameters related to the laser plasma and plasma wave, and establish a model for the interaction between laser and matter to generate plasma waves.

[0009] Step 2: Clean the material to be cleaned based on the vaporization effect mechanism to achieve a removal depth of L2. In step 2, assuming that the room temperature reaches a preset value, an expression for the laser-material interaction time and the temperature at the distance from the laser action surface is established. A one-dimensional heat conduction model is established based on the temperature distribution in the material to be cleaned to calculate the removal depth L2.

[0010] Step 3: Clean the material to be cleaned based on the thermal stress mechanism to achieve a removal depth of L3. In step 3, define the unit type, compile the laser heat source model and stress field expression, solve the stress of each node, and establish the basis for thermal stress-induced coating peeling.

[0011] Step 4: Clean the material to be cleaned based on the evaporation pressure mechanism to achieve a removal depth of L4. In step 4, the pressure generated by the inert gas or target material under stimulation is studied. The shielding effect of the laser-induced plasma is explored to reduce the efficiency of the interaction between the laser and the target material, simulating the actual working conditions during laser cleaning.

[0012] Step 5: Clean the material to be cleaned based on the photon pressure mechanism, achieving a removal depth of L5. In step 5, the workpiece is fixed to a high-precision motion platform, and the laser scanning path and speed are set. The laser system is activated, allowing high-flux photons to impact the surface of the contaminant, generating pressure through momentum transfer, and stripping the contaminant.

[0013] Step 6: Clean the material to be cleaned based on the cold ablation mechanism to achieve a removal depth of L6; in step 6, select an ultraviolet laser with a suitable wavelength so that the photon energy meets the conditions for breaking chemical bonds; by controlling the laser energy and power parameters, allow the ultraviolet laser to act on the material to be cleaned, causing the chemical bonds to break.

[0014] Furthermore, in step 1, during the interaction between laser and matter, the expansion of the laser plasma will generate high-pressure waves, the distribution of which is closely related to the radiation intensity of the incident laser, and its expression is:

[0015]

[0016] Where a is the coefficient determined by the sample material; E q is the laser radiation intensity; λ is the incident laser wavelength; τ is the pulse duration.

[0017] Furthermore, in step 2, assuming that the room temperature is 300K, the laser-matter interaction time t and the temperature T(d,t) at a distance d from the laser action surface are expressed as:

[0018]

[0019] Where E0 is the laser energy density; d is the distance from the laser action surface; t is the interaction time; k is the thermal conductivity of the material to be cleaned; ρ is the density of the material to be cleaned; c p is the specific heat capacity of the material to be cleaned; τ is the pulse duration; I0 is the incident laser intensity;

[0020] in:

[0021]

[0022] α is the thermal diffusivity; A is the absorptivity;

[0023] When the thickness of the material to be cleaned is much smaller than the thickness of the substrate, the temperature T(d,t) is expressed as:

[0024]

[0025] Furthermore, in step 3, the laser pulses with Gaussian distribution in space and time can be described as:

[0026]

[0027] Where Q is the total energy of the laser pulse; D is the effective radius of the laser spot; τ is the pulse duration;

[0028] The difference in thermal expansion properties and temperature between the material to be cleaned and the substrate will produce a thermal stress difference, which is the stress that causes delamination and is expressed as:

[0029] Δσ=σ s -σ p =E s γ s ΔT s -E p γ p ΔT p

[0030] Where, E s is the elastic modulus; γ s is the thermal expansion coefficient; σ p is the thermal stress of the material to be cleaned; σ s is the thermal stress of the substrate.

[0031] Furthermore, in step 4, the expression of the mechanical coupling coefficient is:

[0032]

[0033] Where, P b is the ablation pressure; E l is the laser intensity; I is the incident laser intensity; M is the momentum transferred to the target.

[0034] Furthermore, in step 5, the photon pressure P of the laser cleaning γ Expressed as:

[0035]

[0036] Where, P γ is the photon pressure; h is Planck's constant; λ UV is the wavelength of the photon.

[0037] Furthermore, in step 6, the photon energy formula is expressed as:

[0038] E=hv, where h is Planck's constant and v is the photon frequency.

[0039] The photon frequency is expressed as:

[0040] v=c / λ

[0041] Where c is the speed of light.

[0042] Furthermore, in laser cleaning, the optimal cleaning depth of laser cleaning based on the coupling of different cleaning mechanisms is:

[0043] L 最优 =L1+L2+L3+L4+L5+L6.

[0044] The present invention also proposes an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the laser cleaning method based on the coupling of different cleaning mechanisms are implemented.

[0045] The present invention also provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, implement the steps of the laser cleaning method based on the coupling of different cleaning mechanisms.

[0046] Beneficial effects of the present invention:

[0047] The present invention proposes a laser cleaning method based on the coupling of different cleaning mechanisms. The method takes into account the plasma shock wave effect, vaporization effect, thermal stress, evaporation pressure, photon pressure and cold ablation (breaking molecular bonds), and is a method for laser cleaning dirt on the surface of the substrate under the coupling of these six laser cleaning mechanisms. Secondly, it solves the problem that previous studies only considered a single mechanism study and process study in the laser cleaning process, which could not truly reflect the dynamic characteristics of laser cleaning. Taking into account the coupling of multiple laser cleaning mechanisms, the laser can efficiently remove surface dirt without damaging the substrate surface. Based on this, the proposed laser cleaning method based on the coupling of different cleaning mechanisms more accurately reflects the actual process of laser cleaning the material to be cleaned, and ensures that the substrate material is not damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0049] Figure 1 This is a schematic diagram of the principle of a laser cleaning method based on the coupling of different cleaning mechanisms described in the present invention. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] Specifically, combined Figure 1 The present invention proposes a laser cleaning method based on the coupling of different cleaning mechanisms, the method comprising:

[0052] Step 1: Clean the material to be cleaned based on the plasma shock wave effect mechanism to achieve a removal depth of L1. In step 1, define the thermal and physical properties of the material; clarify the parameters related to the laser plasma and plasma wave, and establish a model for the interaction between laser and matter to generate plasma waves.

[0053] In step 1, during the interaction between laser and matter, the expansion of the laser plasma will generate high-pressure waves, the distribution of which is closely related to the radiation intensity of the incident laser, and its expression is:

[0054]

[0055] Where a is the coefficient determined by the sample material; E q is the laser radiation intensity (J / cm 2 ), λ is the incident laser wavelength (μm), and τ is the pulse duration (ns).

[0056] Step 2: Clean the material to be cleaned based on the vaporization effect mechanism to achieve a removal depth of L2. In step 2, assuming that the room temperature reaches a preset value, an expression for the laser-material interaction time and the temperature at the distance from the laser action surface is established. A one-dimensional heat conduction model is established based on the temperature distribution in the material to be cleaned to calculate the removal depth L2.

[0057] In step 2, assuming that the room temperature is 300K, the laser-matter interaction time t and the temperature T(d,t) at a distance d from the laser action surface are expressed as:

[0058]

[0059] Where E0 is the laser energy density (J / cm 2 ); d is the distance from the laser action surface (μm); t is the interaction time (ns); k is the thermal conductivity of the material to be cleaned (W·m -1 ·k -1 ); ρ is the density of the material to be cleaned (kg·m -3 );c p is the specific heat capacity of the material to be cleaned (J·kg -1 ·K -1 ); τ is the pulse duration (ns); I0 is the incident laser intensity (cd);

[0060] in:

[0061]

[0062] α is the thermal diffusivity; A is the absorptivity (m -1 );

[0063] When the thickness of the material to be cleaned is much smaller than the thickness of the substrate, the temperature T(d,t) is expressed as:

[0064]

[0065] Step 3: Clean the material to be cleaned based on the thermal stress mechanism to achieve a removal depth of L3. In step 3, define the unit type, compile the laser heat source model and stress field expression, solve the stress of each node, and establish the basis for thermal stress-induced coating peeling.

[0066] In step 3, the laser pulses with Gaussian distribution in space and time can be described as:

[0067]

[0068] Where Q is the total energy of the laser pulse; D is the effective radius of the laser spot; τ is the pulse duration;

[0069] The difference in thermal expansion properties and temperature between the material to be cleaned and the substrate will produce a thermal stress difference, which is the stress that causes delamination and is expressed as:

[0070] Δσ=σ s -σ p =E s γ s ΔT s -E p γ p ΔT p

[0071] Where, E s is the elastic modulus; γ s is the thermal expansion coefficient; σ p is the thermal stress of the material to be cleaned; σ s is the thermal stress of the substrate.

[0072] Step 4: Clean the material to be cleaned based on the evaporation pressure mechanism to achieve a removal depth of L4. In step 4, the pressure generated by the inert gas or target material under stimulation is studied. The shielding effect of the laser-induced plasma is explored to reduce the efficiency of the interaction between the laser and the target material, simulating the actual working conditions during laser cleaning.

[0073] In step 4, the expression for the mechanical coupling coefficient is:

[0074]

[0075] Where, P b is the ablation pressure; E l is the laser intensity; I is the incident laser intensity; M is the momentum transferred to the target.

[0076] Step 5: Clean the material to be cleaned based on the photon pressure mechanism, achieving a removal depth of L5. In step 5, the workpiece is fixed to a high-precision motion platform, and the laser scanning path and speed are set. The laser system is activated, allowing high-flux photons to impact the surface of the contaminant, generating pressure through momentum transfer, and stripping the contaminant.

[0077] Photon pressure P of laser cleaning in step 5 γ Expressed as:

[0078]

[0079] Where, P γis the photon pressure (Pa); h is Planck's constant; λ UV is the photon wavelength (μm).

[0080] Step 6: The material to be cleaned is cleaned based on the cold ablation (breaking molecular bonds) mechanism to achieve a removal depth of L6; in step 6, a UV laser of appropriate wavelength is selected so that the photon energy meets the conditions for breaking chemical bonds; by controlling the laser energy and power parameters, the UV laser is allowed to act on the material to be cleaned, causing the chemical bonds to break.

[0081] In step 6, the photon energy formula is expressed as:

[0082] E=hv

[0083] Where h is Planck's constant; v is the photon frequency;

[0084] The photon frequency is expressed as:

[0085] v=c / λ

[0086] Where c is the speed of light.

[0087] In laser cleaning, the optimal cleaning depth based on the coupling of different cleaning mechanisms is:

[0088] L 最优 =L1+L2+L3+L4+L5+L6.

[0089] The present invention also proposes an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the laser cleaning method based on the coupling of different cleaning mechanisms are implemented.

[0090] The present invention also provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, implement the steps of the laser cleaning method based on the coupling of different cleaning mechanisms.

[0091] The memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM bus RAM (DRRAM). It should be noted that the memory of the methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0092] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, a solid state disc (SSD)).

[0093] During implementation, each step of the above method can be completed by an integrated logic circuit of the hardware in the processor or by instructions in the form of software. The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it will not be described in detail here.

[0094] It should be noted that the processor in the embodiments of the present application can be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method embodiment can be completed by an integrated logic circuit of the hardware in the processor or by instructions in the form of software. The above processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The various methods, steps, and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium mature in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0095] The above is a detailed introduction to the laser cleaning method based on the coupling of different cleaning mechanisms proposed in the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A laser cleaning method based on the coupling of different cleaning mechanisms, characterized in that: The method comprises: Step 1: Clean the material to be cleaned based on the plasma shock wave effect mechanism to achieve a removal depth of L1. In step 1, define the thermal and physical properties of the material; clarify the parameters related to the laser plasma and plasma wave, and establish a model for the interaction between laser and matter to generate plasma waves. Step 2: Clean the material to be cleaned based on the vaporization effect mechanism to achieve a removal depth of L2. In step 2, assuming that the room temperature reaches a preset value, an expression for the laser-material interaction time and the temperature at the distance from the laser action surface is established. A one-dimensional heat conduction model is established based on the temperature distribution in the material to be cleaned to calculate the removal depth L2. Step 3: Clean the material to be cleaned based on the thermal stress mechanism to achieve a removal depth of L3. In step 3, define the unit type, compile the laser heat source model and stress field expression, solve the stress of each node, and establish the basis for thermal stress-induced coating peeling. Step 4: Clean the material to be cleaned based on the evaporation pressure mechanism to achieve a removal depth of L4. In step 4, the pressure generated by the inert gas or target material under stimulation is studied. The shielding effect of the laser-induced plasma is explored to reduce the efficiency of the interaction between the laser and the target material, simulating the actual working conditions during laser cleaning. Step 5: Clean the material to be cleaned based on the photon pressure mechanism, achieving a removal depth of L5. In step 5, the workpiece is fixed to a high-precision motion platform, and the laser scanning path and speed are set. The laser system is activated, allowing high-flux photons to impact the surface of the contaminant, generating pressure through momentum transfer, and stripping the contaminant. Step 6: Clean the material to be cleaned based on the cold ablation mechanism to achieve a removal depth of L6; in step 6, select an ultraviolet laser with a suitable wavelength so that the photon energy meets the conditions for breaking chemical bonds; by controlling the laser energy and power parameters, allow the ultraviolet laser to act on the material to be cleaned, causing the chemical bonds to break.

2. The method according to claim 1, characterized in that In step 1, during the interaction between laser and matter, the expansion of the laser plasma will generate high-pressure waves, the distribution of which is closely related to the radiation intensity of the incident laser, and its expression is: Where a is the coefficient determined by the sample material; E q is the laser radiation intensity; λ is the incident laser wavelength; τ is the pulse duration.

3. The method according to claim 1, characterized in that In step 2, assuming that the room temperature is 300K, the laser-matter interaction time t and the temperature T(d,t) at a distance d from the laser action surface are expressed as: Where E0 is the laser energy density; d is the distance from the laser action surface; t is the interaction time; k is the thermal conductivity of the material to be cleaned; ρ is the density of the material to be cleaned; c p is the specific heat capacity of the material to be cleaned; τ is the pulse duration; I0 is the incident laser light intensity; in: α is the thermal diffusivity; A is the absorptivity; When the thickness of the material to be cleaned is much smaller than the thickness of the substrate, the temperature T(d,t) is expressed as:

4. The method according to claim 1, wherein In step 3, the laser pulses with Gaussian distribution in space and time can be described as: Where Q is the total energy of the laser pulse; D is the effective radius of the laser spot; τ is the pulse duration; The difference in thermal expansion properties and temperature between the material to be cleaned and the substrate will produce a thermal stress difference, which is the stress that causes delamination and is expressed as: Ds = s s -s p =E s c s ΔT s -E p c p ΔT p Where, E s is the elastic modulus; γ s is the thermal expansion coefficient; σ p is the thermal stress of the material to be cleaned; σ s is the thermal stress of the substrate.

5. The method according to claim 1, characterized in that In step 4, the expression for the mechanical coupling coefficient is: Where, P b is the ablation pressure; E l is the laser intensity; I is the incident laser intensity; M is the momentum transferred to the target.

6. The method according to claim 1, wherein Photon pressure P of laser cleaning in step 5 γ Expressed as: Where, P γ is the photon pressure; h is Planck's constant; λ UV is the wavelength of the photon.

7. The method according to claim 1, characterized in that In step 6, the photon energy formula is expressed as: E=hv Where h is Planck's constant; v is the photon frequency; The photon frequency is expressed as: v=c / λ Where c is the speed of light.

8. The method according to claim 1, characterized in that In laser cleaning, the optimal cleaning depth based on the coupling of different cleaning mechanisms is: <h2 style=";text-align:left;direction:ltr">L<h2 style=";text-align:left;direction:ltr"> 最优 <h2 style=";text-align:left;direction:ltr"> (L1+L2+L3+L4+L5+L6) 9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium for storing computer instructions, characterized in that: When the computer instructions are executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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