CN102737137A - Optimization method for technological parameters of laser fine drilling - Google Patents

Abstract

The invention provides an optimization method for technological parameters of laser fine drilling. The method mainly comprises the following steps: 1) determining a target hole type; 2) carrying out a prediction of the technological parameters and a numerical simulation according to the target hole type; 3) carrying out practical punching experiment according to the technological parameters in the numerical simulation; 4) and carrying out optimization to the technological parameters, such that target technological parameters are obtained. The optimization method for the technological parameters of the laser subtle punching provided in the invention can save plenty of trial tests at an early stage. With the method, workload is greatly reduced, test cost is reduced to a maximum extent and processing efficiency is improved.

Description

The precise and tiny drilling technology parameter optimization method of a kind of laser

Technical field

The present invention relates to the precise and tiny drilling technology Parameter Optimization of laser method, belong to the laser ablation technical field.

Background technology

Along with industrial expansions such as Aero-Space, electronics, medicine equipments, the key components and parts of many high, refined, peak products all need design many micropores, with the completion specific function, thereby improves performance of products.Such as aero engine turbine blades, guide vane, firing chamber need up to ten thousand micropores to realize the effect of cooling in modern times.Laser drilling with its can get big aspect ratio hole, advantage such as speed is fast, rapidoprint is unrestricted, replace traditional diamond-making technique gradually and be used widely at some manufacture fields.

For the precise and tiny punching technology of laser, relate to material character (material properties, hot rerum natura), material geometric parameter (thickness, length and width etc.), laser parameter multiparameter problems such as (laser power, width pulse number, protection atmospheric pressure, defocusing amounts etc.).When actual converted products, need obtain the laser hole of specific size and shape, because above-mentioned influence factor is various, cause actual the groping property test in a large number in man-hour that adds, very easily cause the destruction of material and the waste of processing cost.Therefore, effective control of the cost of the precise and tiny punching of laser be realized, the prediction and the optimization of laser boring must be explored.

At present; To the analysis of the research spininess of laser boring to Physical Mechanism; And the situation when all not beating with laser is a research object; Still need grope in a large number in the time of the actual processing of laser boring,, not see relevant research report or the patented technology of announcing at present as yet for precise and tiny drilling technology parameter prediction of laser and optimization.

Summary of the invention

1), confirm the target pass the present invention provides the precise and tiny drilling technology Parameter Optimization of a kind of laser method, and this method mainly may further comprise the steps:; 2), according to the target pass, carry out technological parameter prediction, the emulation of the line number of going forward side by side value; 3), carry out actual punching experiment according to the technological parameter in the numerical simulation then; 4), technological parameter is optimized, finally obtain the target process parameter.

Further, said step 2) be specially:, carry out the prediction of numerical simulation and technological parameter according to the target pass that step 1) sets; Set up two dimension (X-Y) physical model of laser drilling process; According to the Nonlinear Heat Conduction equation is formula (1), calculates the temperature field evolutionary process of laser boring, and exports the pass and the technological parameter that possibly meet the demands:

The two-dimension non linearity Transient Heat Transfer thermal balance equation of laser drilling process:

$\mathrm{\ρc}\frac{\∂T}{\∂t}=\frac{\∂}{\∂x}\left(k\frac{\∂T}{\∂x}\right)+\frac{\∂}{\∂y}\left(k\frac{\∂T}{\∂y}\right)---\left(1\right)$

In the formula: T is a temperature, and ρ is a density, and c is a specific heat capacity, and k is a heat-conduction coefficient.Further, said Nonlinear Heat Conduction equation is in the formula (1): because laser boring is the heat transfer process of unstable state,

Its boundary condition and starting condition are:

Starting condition is got the Temperature Distribution of laser boring initial time, is environment temperature:

T(x，y，0)＝T ₀ (2)

On the laser action surface,

$k\frac{\∂T}{\∂y}=\left(\frac{\mathrm{\ϵ\αP}}{\mathrm{\πr}{\left(y\right)}^2}\right)\exp [-\frac{\mathrm{\ϵ}{x}^2}{r{\left(y\right)}^2}]---\left(3\right)$

P is a laser power in the formula; R (y) is the laser beam radius; ε is a hot-fluid intensity coefficient, gets 1,2 corresponding to ε, and during 3 value, the energy distribution number percent of Gauss's thermal source is respectively 63.2%, 86.4%, 95.02%; α is the absorptivity of material for laser light, and k is a heat-conduction coefficient.P is a laser pulse power.

Further, said Nonlinear Heat Conduction equation is in the formula (1): in laser drilling process, have the fusing even the vaporization phenomenon of material, so in this process, exist the phase transformation problem.And, can absorb or emit latent heat, i.e. latent heat of phase change during phase transformation.Latent heat of phase change can influence the size that workpiece absorbs laser energy on certain degree; Enthalpy through the definition material is considered latent heat with temperature variation, promptly

H＝∫ρcdT (4)

In the formula, H is a heat enthalpy value, and T is a temperature, and ρ is a density, and c is a specific heat capacity.

Further, said step 3) is specially: said laser boring engineer testing: this engineer testing comprises laser boring test and to the test observation two parts in cross section, hole.

Further, the pulse laser manufacturing system is adopted in said laser boring test, uses said step 2) in prediction obtained laser parameter and carried out the laser boring test; And carry out line cutting through the laser hole that sample is obtained, the polishing back is in the shape and size in three-dimensional microscopic hole.

Further, said step 4) comprises:

Gap between A, comparison numerical simulation pass and the actual pass, the adjusting process parameter;

B, repeating step 3) and 4), the target process parameter finally obtained.

Further, said process parameter optimizing is specially: contrast the pass that target pass and step 3) obtain, obtain both difference; According to step 2) in the variation tendency of the various passes of being simulated; The adjusting process parameter is carried out step 3), again until the pass that is met requirement.

Further, the parameter in the said physical model comprises real material shape, size, and laser loads the zone, finite element grid is divided.

Description of drawings

Fig. 1 is the precise and tiny drilling technology parameter optimization method of laser concrete steps block diagrams;

Fig. 2 is a finite element grid;

Fig. 3 is for passing through the resulting pass figure of finite element grid emulation;

Fig. 4 is the resulting pass sectional view of actual punching experiment;

Fig. 5 is for testing resulting straight tube pass figure through actual punching after the parameter adjustment.

Embodiment

Fig. 1 is the step block diagram in the laser boring method of the present invention, but by the precise and tiny drilling technology Parameter Optimization of the laser method in this block diagram knowledge capital invention, mainly may further comprise the steps:

1, confirms the target pass;

2,, carry out the technological parameter prediction, the emulation of the line number of going forward side by side value according to the target pass;

3, carry out actual punching experiment according to the technological parameter in the numerical simulation then;

4, the gap between comparison numerical simulation pass and the actual pass, the adjusting process parameter;

5, repeating step 3,4, finally obtain the target process parameter.

Above-mentioned steps is specific as follows:

1, confirms the target pass that actual punching work is required;

2, laser boring and technological parameter prediction: the target pass that sets according to step 1; Carry out the prediction of numerical simulation and technological parameter.Because numerical simulation has characteristics such as efficient, that cost is low than actual punching test, numerical value emulation method is adopted in the technological parameter prediction among the present invention.Consider that laser beam and hole all have axisymmetric characteristics, set up the two-dimentional physical model of reflection laser drilling process.Parameter in the physical model comprises real material shape, size, and laser loads the zone, finite element grid is divided.According to the Nonlinear Heat Conduction equation is formula (1), calculates the temperature field evolutionary process of laser boring, and exports the pass and the technological parameter that possibly meet the demands.

The two-dimension non linearity Transient Heat Transfer thermal balance equation of laser drilling process:

$\mathrm{\ρc}\frac{\∂T}{\∂t}=\frac{\∂}{\∂x}\left(k\frac{\∂T}{\∂x}\right)+\frac{\∂}{\∂y}\left(k\frac{\∂T}{\∂y}\right)---\left(1\right)$

In the formula: T is a temperature, and ρ is a density, and c is a specific heat capacity, and k is a heat-conduction coefficient.

Laser boring is the heat transfer process of unstable state, and its boundary condition and starting condition are:

Starting condition is got the Temperature Distribution of laser boring initial time, is environment temperature:

T(x，y，0)＝T ₀ (2)

On the laser action surface,

$k\frac{\∂T}{\∂y}=\left(\frac{\mathrm{\ϵ\αP}}{\mathrm{\πr}{\left(y\right)}^2}\right)\exp [-\frac{\mathrm{\ϵ}{x}^2}{r{\left(y\right)}^2}]---\left(3\right)$

P is a laser power in the formula; R (y) is the laser beam radius; ε is a hot-fluid intensity coefficient, gets 1,2 corresponding to ε, and during 3 value, the energy distribution number percent of Gauss's thermal source is respectively 63.2%, 86.4%, 95.02%; α is the absorptivity of material for laser light, and k is a heat-conduction coefficient.P is a laser pulse power.

The fusing even the vaporization phenomenon that in laser drilling process, have material are so exist the phase transformation problem in this process.And, can absorb or emit latent heat, i.e. latent heat of phase change during phase transformation.Latent heat of phase change can influence the size that workpiece absorbs laser energy on certain degree.Generally be to consider latent heat with temperature variation, promptly through the enthalpy of definition material

H＝∫ρcdT (4)

In the formula, H is a heat enthalpy value, and T is a temperature, and ρ is a density, and c is a specific heat capacity.

To the characteristics of laser boring, the interface that algorithm reasonable in design is found the solution variation of temperature in the laser drilling process and caught aperture changes, and finally provides the technological parameter that satisfies specific pass.

3, laser boring engineer testing: this engineer testing comprises laser boring test and to the test observation two parts in cross section, hole.The pulse laser manufacturing system is adopted in the laser boring test, and adjustable technological parameter comprises pulsed laser power, pulsewidth, pulse number, dutycycle etc.; Obtain laser parameter with step 2 prediction and carried out the laser boring test.The laser hole that sample is obtained carries out the line cutting, and the polishing back is in the shape and size in three-dimensional microscopic hole.

4, process optimization: the pass that target pass that sets in the contrast step 1 and step 3 obtain; Obtain both difference, according to the variation tendency of the various passes of being simulated in the step 2, the adjusting process parameter; Again carry out step 3, until the pass that is met requirement.

Below in conjunction with accompanying drawing and practical implementation example, method provided by the invention is further specified:

Many parts often need process the aperture of given shape in order to satisfy the special performances requirement in the modern industry manufacturing, such as straight barrel type, just tapered, back taper type diplodal.In order to satisfy performance requirement, often need the trickle aperture of a large amount of straight barrel types such as engine turbine blade, atomizer etc.

Following specific embodiment is explained concrete steps of the present invention:

1, confirms the target pass: the laser hole that requires to obtain the about 0.2mm straight barrel type in aperture at thick 301 corrosion resistant plates of 1mm.Material composition is following:

Table 1 301 stainless chemical constitutions (massfraction, %)

2, the numerical simulation of laser boring and technological parameter prediction: as shown in Figure 2, consider the aperture less than the laser action territory of 0.3mm in the 1mm scope, set up the computational fields of 2mm * 1mm, to the stainless material properties of its assignment and divide finite element grid.Finite element model is carried out laser drilling process emulation, exploratory laser parameter such as table 2, the pass that emulation obtains such as Fig. 3.

Table 2 laser technical parameters

3, laser boring engineer testing: laser technical parameters shown in the his-and-hers watches 2 carries out the laser boring test, and it is as shown in Figure 4 that each pass is observed in the test back.

4, process optimization: the pass analysis to step 2 obtains can find out that when changing to positive defocusing amount with laser technical parameters from bearing defocusing amount, pass is from the just tapered back taper type that changes to; Hole dimension changes when under same defocusing amount, changing pulsewidth, and pass changes little.Given this, the technological parameter that can guess the straight barrel type hole that requirement obtains in technological parameter Fig. 4 3. about.Consider the relatively poor characteristics of practical laser test repeatability, through 3. pairing technological parameter among Fig. 4 is repeatedly done the pass that inching can be met requirement, as shown in Figure 5; Technological parameter is laser pulse power 1000W; Pulsewidth 2ms, pulse number 1, defocusing amount-0.1.

Can find out from said process; The precise and tiny drilling technology Parameter Optimization of disclosed laser method is carried out emulation through programmed algorithm reasonable in design to laser drilling process among the present invention; The laser boring technological parameter of actual pass and dimensional requirement is satisfied in tentative prediction; And carry out the practical laser punching with this parameter and test, through comparative test result and result of calculation adjustment laser processing parameter, final definite technological parameter and pass that needs.The precise and tiny drilling technology parameter optimization method of laser provided by the invention can be saved a large amount of investigative test in laser boring test early stage, has reduced workload greatly, has at utmost reduced experimentation cost, has improved working (machining) efficiency.

Claims (9)

1. precise and tiny drilling technology parameter optimization method of laser, it is characterized by: said method mainly may further comprise the steps:

1), confirms the target pass;

2), according to the target pass, carry out technological parameter prediction, the emulation of the line number of going forward side by side value;

3), carry out actual punching experiment according to the technological parameter in the numerical simulation then;

4), technological parameter is optimized, finally obtain the target process parameter.

2. according to the precise and tiny drilling technology parameter optimization method of laser described in the claim 1, it is characterized by said step 2) be specially: according to the target pass that step 1) sets, carry out the prediction of numerical simulation and technological parameter; Set up the two-dimentional physical model of laser drilling process; According to the Nonlinear Heat Conduction equation is formula (1), calculates the temperature field evolutionary process of laser boring, and exports the pass and the technological parameter that possibly meet the demands:

The two-dimension non linearity Transient Heat Transfer thermal balance equation of laser drilling process:

$\mathrm{\ρc}\frac{\∂T}{\∂t}=\frac{\∂}{\∂x}\left(k\frac{\∂T}{\∂x}\right)+\frac{\∂}{\∂y}\left(k\frac{\∂T}{\∂y}\right)---\left(1\right)$

In the formula: T is a temperature, and ρ is a density, and c is a specific heat capacity, and k is a heat-conduction coefficient.

3. according to the precise and tiny drilling technology parameter optimization method of laser described in the claim 2, it is characterized by, said Nonlinear Heat Conduction equation is in the formula (1): because laser boring is the heat transfer process of unstable state, its boundary condition and starting condition are:

Starting condition is got the Temperature Distribution of laser boring initial time, is environment temperature:

T(x，y，0)＝T ₀ (2)

On the laser action surface,

$k\frac{\∂T}{\∂y}=\left(\frac{\mathrm{\ϵ\αP}}{\mathrm{\πr}{\left(y\right)}^2}\right)\exp [-\frac{\mathrm{\ϵ}{x}^2}{r{\left(y\right)}^2}]---\left(3\right)$

P is a laser power in the formula; R (y) is the laser beam radius; ε is a hot-fluid intensity coefficient, gets 1,2 corresponding to ε, and during 3 value, the energy distribution number percent of Gauss's thermal source is respectively 63.2%, 86.4%, 95.02%; α is the absorptivity of material for laser light, and k is a heat-conduction coefficient.P is a laser pulse power.

4. according to the precise and tiny drilling technology parameter optimization method of laser described in the claim 2; It is characterized by; Said Nonlinear Heat Conduction equation is in the formula (1): in laser drilling process, have the fusing even the vaporization phenomenon of material, so in this process, exist the phase transformation problem.And, can absorb or emit latent heat, i.e. latent heat of phase change during phase transformation.Latent heat of phase change can influence the size that workpiece absorbs laser energy on certain degree; Enthalpy through the definition material is considered latent heat with temperature variation, promptly

H＝∫ρcdT (4)

In the formula, H is a heat enthalpy value, and T is a temperature, and ρ is a density, and c is a specific heat capacity.

5. according to the precise and tiny drilling technology parameter optimization method of laser described in the claim 1, it is characterized by, said step 3) is specially: said smooth drilling technology test: this engineer testing comprises the laser boring test and to the test observation two parts in cross section, hole.

6. according to the precise and tiny drilling technology parameter optimization method of laser described in the claim 5, it is characterized by, the pulse laser manufacturing system is adopted in said laser boring test, uses said step 2) in prediction obtained laser parameter and carried out the laser boring test; And carry out line cutting through the laser hole that sample is obtained, the polishing back is in the shape and size in three-dimensional microscopic hole.

7. according to the precise and tiny drilling technology parameter optimization method of laser described in the claim 1, it is characterized by, said step 4) comprises:

Gap between A, comparison numerical simulation pass and the actual pass, the adjusting process parameter;

B, repeating step 3) and 4), the target process parameter finally obtained.

8. according to the precise and tiny drilling technology parameter optimization method of laser described in the claim 7; It is characterized by, said process parameter optimizing is specially: contrast the pass that target pass and step 3) obtain, obtain both difference; According to step 2) in the variation tendency of the various passes of being simulated; The adjusting process parameter is carried out step 3), again until the pass that is met requirement.

9. according to the precise and tiny drilling technology parameter optimization method of laser described in the claim 2, it is characterized by, the parameter in the said physical model comprises real material shape, size, and laser loads the zone, finite element grid is divided.

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