CN104889565A - Laser machining method and system - Google Patents
Laser machining method and system Download PDFInfo
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- CN104889565A CN104889565A CN201510278790.4A CN201510278790A CN104889565A CN 104889565 A CN104889565 A CN 104889565A CN 201510278790 A CN201510278790 A CN 201510278790A CN 104889565 A CN104889565 A CN 104889565A
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Abstract
The invention provides a laser machining method and system. The method comprises the steps of obtaining first super-short-pulse laser with the laser pulse width shorter than or equal to 10 picoseconds, and machining machined workpieces through the first super-short-pulse laser. According to the scheme of the laser machining method and system, an accurate and clean machining process can be provided for workpiece machining.
Description
Technical field
The present invention relates to a kind of technical field of laser processing, particularly relate to a kind of laser processing and system of processing.
Background technology
Carry out in the process of processing utilizing laser, heat on workpiece can from Laser Focusing point to external diffusion, make the size of melt region much larger than the size of Laser Focusing point, therefore be difficult under normal circumstances accomplish microfabrication, the machining accuracy of the thermal diffusion namely in laser processing procedure to workpiece has adverse effect.
Random process model in addition in part material also can affect machining accuracy.Particularly, after laser pulse enters the material moderate rain of workpiece, start to produce electronics stimulated oscillation, bound electron because being limited to fixed position, so only produce vibration by a small margin; And the free electron do not carried the baby is once be excited just by intense oscillations, and free electron occasional encounters neighbouring atom, if laser field intensity is enough large, in the process of the atom near free-electron collision, can kick out of by the electronics in the atom that collides from the energy level of constraint, so there has been two free electrons; And these two free electrons remove to collide out the electronics in the atom near two other again, so repeatedly go down, this kind of multiplier effect is referred to as avalanche effect always.And when carrying out the higher Laser Processing of machining accuracy to workpiece, above-mentioned avalanche effect is required.At the beginning time, if the free electron not having stock to walk, just there is no the beginning of avalanche process, just cannot realize the processing of laser pulse to workpiece yet.In metal material, there is free electron very fully, therefore avalanche process is almost occur at once, makes the repeatability of processing splendid.But in semiconductor or insulator, free electron is relatively less, so avalanche process may not be certain to occur at once, this depends on whether light beam gets to free electron, suppose that electromagnetic field is interior at the beginning and there are some free electrons, Na Jia trade union seems more efficient, if do not have, avalanche effect can not start, so the process of processing just must lean on a little fortune, this causes the unstability of processing, instant laser pulse is that the focus point size of highly stable and each pulse is the same with energy size, the result of processing still can be different, this realizes very trickle processing and brings very serious restriction, therefore be also unfavorable for improving machining accuracy.
Summary of the invention
The invention provides a kind of laser processing and system of processing, can machining accuracy be improved.
For achieving the above object, one aspect of the present invention provides a kind of laser processing, comprising:
Obtain laser pulse width be shorter than or equal the first ultra-short pulse laser of 10 psecs;
Described first ultra-short pulse laser is utilized to process workpiece.
In a preferred embodiment, described method also comprises: before being processed workpiece by the first ultra-short pulse laser, and the elect magnetic field between described workpiece and described first ultra-short pulse laser is pre-formed at least one free electron.
In a preferred embodiment, laser pre-pulse realizes particular by applying to described workpiece to be pre-formed at least one free electron described in.
In a preferred embodiment, described laser pre-pulse comprises Ultra-Violet Laser prepulsing or femtosecond laser prepulsing.
In a preferred embodiment, in the process utilizing described first ultra-short pulse laser to process workpiece, control the peak fractions that part that intensity in the light beam of described first ultra-short pulse laser exceedes the intensity threshold processing described workpiece only has described light beam.
The present invention also provides a kind of laser-processing system on the other hand, comprising:
First ultrashort pulse laser, for obtaining the first ultra-short pulse laser that laser pulse width is shorter than or equals 10 psecs;
Workpiece, processes it for utilizing described first ultra-short pulse laser.
In a preferred embodiment, before being processed workpiece by the first ultra-short pulse laser, the elect magnetic field between described workpiece and described first ultra-short pulse laser is pre-existing at least one free electron.
In a preferred embodiment, described laser-processing system also comprises:
Prepulse laser generating means, for applying laser pre-pulse to described workpiece in advance, is pre-formed at least one free electron with the elect magnetic field between described workpiece and described first ultra-short pulse laser.
In a preferred embodiment, described Prepulse laser generating means is Ultra-Violet Laser prepulsing generating means or femtosecond laser prepulsing generating means.
In a preferred embodiment, described first ultrashort pulse laser also for applying laser pre-pulse to described workpiece in advance, is pre-formed at least one free electron to make the elect magnetic field between described workpiece and described first ultra-short pulse laser.
By the scheme that the embodiment of the present invention provides, not only accurate but also clean process can be provided for workpiece.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present application or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, the accompanying drawing that the following describes is only some embodiments recorded in the application, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the schematic diagram of a kind of laser processing that one embodiment of the invention provides;
Fig. 2 is the schematic diagram of a kind of laser processing that another embodiment of the present invention provides;
Fig. 3 is the schematic diagram of a kind of laser-processing system that one embodiment of the invention provides;
Fig. 4 is the schematic diagram of a kind of laser-processing system that another embodiment of the present invention provides.
Detailed description of the invention
Technical scheme in the application is understood better in order to make those skilled in the art person, below in conjunction with the accompanying drawing in the embodiment of the present application, technical scheme in the embodiment of the present application is clearly and completely described, obviously, described embodiment is only some embodiments of the present application, instead of whole embodiments.Based on the embodiment in the application, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all should belong to the scope of the application's protection.
The embodiment of the present invention provides a kind of laser processing, and as shown in Figure 1, the method comprises the steps:
Step S101: obtain laser pulse width and be shorter than or equal the first ultra-short pulse laser of 10 psecs;
Step S102: the first ultra-short pulse laser utilizing step S101 to obtain is processed workpiece.
Inventor thinks after having carried out detailed analytic demonstration to laser pulse to the various mechanisms that the workpiece of the materials such as metal carries out producing in process, when laser pulse acts on metal material, due to reverse bremsstrahlung, the energy of laser can be absorbed by free electron.Then, absorbed laser energy needs thermalization in electronic system, and by Energy Transfer in singing powerfully, the Energy Transfer due to electronics gives welding target, causes energy to run off.And electronic specific heat is well below the specific heat capacity of lattice, therefore electrons is heated to a very high transient temperature, and there are three characteristic times amounts in this process, is τ cool time of electronics respectively
e=C
e/ γ, the heat time τ of lattice
i=C
i/ γ, the duration τ of laser pulse
l, wherein cool time much smaller than heat time of lattice of electronics.Under the condition of femtosecond pulse, laser pulse duration is much smaller than the cool time of electronics, now can ignore electron-lattice coupling, when melting work piece surface with femtosecond pulse, touching time of workpiece solid very shortly just can complete fusion processes, so this process regards the direct enterprise planning (or direct liquefaction of solid) of solid as, now lattice is heated in 1ps, object becomes gaseous state or ionic state, and then spreads fast in a vacuum.The heat transfer of whole process has been left in the basket in first approximation, is confirmed, can carry out accurate and clean process by femtosecond pulse to the workpiece of metal material by practice.
And inventor simultaneously also tests and analyzes picosecond pulse laser and ps pulsed laser and ns pulsed laser to the process of metal processing piece.In the process utilizing picosecond pulse laser to process metal processing piece, duration of pulse laser is much smaller than the heat time of lattice, cool time of electronics is much smaller than the duration of pulse laser, this makes the logarithm of depth of fusion and laser energy still set up, and laser fusion is all melted the formation in region with Electron Heat Conduction and metal inside.And in the process of metal processing piece being processed at ps pulsed laser and ns pulsed laser, duration of pulse laser is much larger than the heat time of lattice, in this laser pulse range, the first heated metal surfaces of absorbed laser energy is to fusing point, and then to evaporating temperature, compared with thawing, evaporation of metal needs more energy, in whole process, main energy disappearance occurs when heat transfer enters liquefactent.Due to the Evaporation Phenomenon of liquid metal, use nanosecond laser accurate that molten metal is very difficult in a vacuum.
Specific implementation of the present invention is described in detail below with a concrete embodiment.
As shown in Figure 2, the laser processing that another embodiment of the present invention provides comprises the steps:
Step S201: the elect magnetic field near workpiece is pre-formed at least one free electron.
Here free electron is the basis of avalanche process, determines the precision and stability that later use ultra-short pulse laser is processed workpiece.
When the material of workpiece is metal, owing to inherently there is free electron very fully in metal.But the workpiece of nonmetallic materials does not sometimes have free electron before being processed by laser pulse, need to take measures in advance to make nonmetallic materials produce enough free electrons for this reason, improve processing stability and the machining accuracy of process for un-metal material part.
Can pass through to apply laser pre-pulse to workpiece in practice, the elect magnetic field realized near workpiece forms sufficient free electron.In nonmetallic materials, there is a large amount of electronics, just the overwhelming majority is all bound electron, directly cannot form avalanche process, and bound electron can be changed into free electron by applying laser pre-pulse, is also just conducive to forming avalanche process.Ultra-Violet Laser prepulsing or femtosecond laser prepulsing can be selected as above-mentioned laser pre-pulse, and bound electron can be become free electron by these two kinds of laser pre-pulse instantaneously.
For femtosecond laser prepulsing, this ultrafast laser can produce very high peak power, when ultrashort pulse enters part material, namely start to cause electronics stimulated oscillation, and the superpower electromagnetic field that ultrafast laser produces can make bound electron moment become free electron from being suggested rank, can create the environment that has a large amount of free electron, also therefore avalanche process can launch immediately at once.
Step S202: obtain laser pulse width and be shorter than or equal the first ultra-short pulse laser of 10 psecs.
Step S203: utilize in step S202 to obtain and starve the first ultra-short pulse laser and process described workpiece, and control in the light beam of the first ultra-short pulse laser, the part that intensity exceedes workpiece processing threshold value only has the peak fractions of this light beam.
Owing to having obtained the free electron needed for avalanche process in step s 201, so avalanche process can start immediately, and then stably can complete the process of the first ultra-short pulse laser to workpiece.
Utilizing pulse laser, added to workpiece man-hour, if want to reach minimum characteristic size, the minimum dimension that can accomplish must be focused of the light beam into, usually under the prerequisite not considering fuel factor, this minimum size is approximately the centre wavelength size of laser, the such as laser of 1 microns central wavelength, the size of minimum light beam focus point is exactly approximately 1 micron.
On this basis, inventor further provides and controls the feature size downsizing of Laser Processing to the scheme far below centre wavelength, particularly, first the first ultra-short pulse laser is focused on, present Gaussian Profile in the light intensity distributions of the focus point of work piece surface; Owing to there is not fuel factor, need the intensity threshold considering this workpiece of processing, the part only exceeding this intensity threshold can be processed, the peak fractions that part that intensity in the light beam of the first ultra-short pulse laser exceedes this intensity threshold only has this light beam can be controlled for this reason, very little localized area just can be only had processed, and the size of this localized area even can be so small to have only 1/10th of light beam focus point size.The femtosecond pulse being such as 0.2 micron with a centre wavelength is processed workpiece, and optimal situation can reach the processing dimension of only about 20 nanosizeds, and this cannot accomplish at traditional Long Pulse LASER.
The laser processing that the embodiment of the present invention provides, the workpiece of nearly all material can be processed, and process can not pollute workpiece, there is no melting residue, microcrack, the ripple that shakes, double teeming district or peel ply, also can not injure other micro-structurals, the product utilizing laser processing provided by the invention to process can directly use.
The embodiment of the present invention is corresponding also provides a kind of laser-processing system, and as shown in Figure 3, this laser-processing system 30 comprises the first ultrashort pulse laser 31 and workpiece 32.Wherein the first ultrashort pulse laser 31 is shorter than for obtaining laser pulse width or equals the first ultra-short pulse laser of 10 psecs, and workpiece 32 is processed it for utilizing the first ultra-short pulse laser.
Fig. 4 shows the one implementation more specifically of the laser-processing system in the present invention, as shown in Figure 4, the laser-processing system 40 of this specific implementation comprises femtosecond pulse laser 41, polarized controller 42, prepulsing control device 43, optical focusing system 44 and workpiece 45.
Femtosecond pulse laser 41 is the pulse laser of femtosecond magnitude for output pulse width.Polarized controller 42 carries out Polarization Control for the laser exported femtosecond pulse laser 41, improve the peak power of laser and reduce the pulse width of laser pulse further, usual above-mentioned polarized controller 42 can be made up of a half-wave plate (i.e. 1/2 wave plate) and a PBS optical splitter.
Prepulsing control device 43 processes for the laser realized femtosecond pulse laser 41 exports, obtain the effect of prepulsing, realize thus just not only to produce prepulsing by a laser instrument, but also the object of the first ultra-short pulse laser for processing workpiece being produced.Those skilled in the art should be understood that, also Prepulse laser generating means can be set separately in addition in practice, for applying laser pre-pulse to workpiece in advance, be pre-formed at least one free electron with the elect magnetic field between workpiece and the first ultra-short pulse laser, Prepulse laser generating means here can be Ultra-Violet Laser prepulsing generating means or femtosecond laser prepulsing generating means.
Optical focusing system 44 for focusing on the pulsed laser beam exported from prepulsing control device 43, to reduce the size of the hot spot that light beam irradiates on workpiece 45.
Although depict the application by embodiment, those of ordinary skill in the art know, the application has many distortion and change and do not depart from the spirit of the application, and the claim appended by wishing comprises these distortion and change and do not depart from the spirit of the application.
Claims (10)
1. a laser processing, is characterized in that, comprising:
Obtain laser pulse width be shorter than or equal the first ultra-short pulse laser of 10 psecs;
Described first ultra-short pulse laser is utilized to process workpiece.
2. method according to claim 1, it is characterized in that, described method also comprises: before being processed workpiece by the first ultra-short pulse laser, and the elect magnetic field between described workpiece and described first ultra-short pulse laser is pre-formed at least one free electron.
3. method according to claim 2, is characterized in that, described in be pre-formed at least one free electron laser pre-pulse realize particular by applying to described workpiece.
4. method according to claim 3, is characterized in that, described laser pre-pulse comprises Ultra-Violet Laser prepulsing or femtosecond laser prepulsing.
5. method according to claim 1, it is characterized in that, in the process utilizing described first ultra-short pulse laser to process workpiece, control the peak fractions that part that intensity in the light beam of described first ultra-short pulse laser exceedes the intensity threshold processing described workpiece only has described light beam.
6. a laser-processing system, is characterized in that, comprising:
First ultrashort pulse laser, for obtaining the first ultra-short pulse laser that laser pulse width is shorter than or equals 10 psecs;
Workpiece, processes it for utilizing described first ultra-short pulse laser.
7. system according to claim 6, is characterized in that, before being processed workpiece by the first ultra-short pulse laser, the elect magnetic field between described workpiece and described first ultra-short pulse laser is pre-existing at least one free electron.
8. system according to claim 7, is characterized in that, described laser-processing system also comprises:
Prepulse laser generating means, for applying laser pre-pulse to described workpiece in advance, is pre-formed at least one free electron with the elect magnetic field between described workpiece and described first ultra-short pulse laser.
9. system according to claim 8, is characterized in that, described Prepulse laser generating means is Ultra-Violet Laser prepulsing generating means or femtosecond laser prepulsing generating means.
10. system according to claim 7, described first ultrashort pulse laser also for applying laser pre-pulse to described workpiece in advance, is pre-formed at least one free electron to make the elect magnetic field between described workpiece and described first ultra-short pulse laser.
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| CN201510278790.4A CN104889565A (en) | 2015-05-27 | 2015-05-27 | Laser machining method and system |
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| CN201510278790.4A CN104889565A (en) | 2015-05-27 | 2015-05-27 | Laser machining method and system |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH611192A5 (en) * | 1977-04-14 | 1979-05-31 | Lasag Ag | Method of removing material from a metallic workpiece, in particular for boring, by means of a laser-beam pulse focused on the material to be removed |
| CN101028670A (en) * | 2007-04-09 | 2007-09-05 | 中国科学院西安光学精密机械研究所 | Method and apparatus for producing fibre-optical FP sensor by ultrashort pulse laser fine machining |
| CN102909474B (en) * | 2012-10-24 | 2015-05-13 | 天津大学 | Method for welding transparent material |
| CN102962589B (en) * | 2012-11-28 | 2015-05-20 | 江苏金方圆数控机床有限公司 | Pulse laser drilling device and drilling method thereof |
| CN204603561U (en) * | 2015-05-27 | 2015-09-02 | 广东高聚激光有限公司 | A kind of laser-processing system |
-
2015
- 2015-05-27 CN CN201510278790.4A patent/CN104889565A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH611192A5 (en) * | 1977-04-14 | 1979-05-31 | Lasag Ag | Method of removing material from a metallic workpiece, in particular for boring, by means of a laser-beam pulse focused on the material to be removed |
| CN101028670A (en) * | 2007-04-09 | 2007-09-05 | 中国科学院西安光学精密机械研究所 | Method and apparatus for producing fibre-optical FP sensor by ultrashort pulse laser fine machining |
| CN102909474B (en) * | 2012-10-24 | 2015-05-13 | 天津大学 | Method for welding transparent material |
| CN102962589B (en) * | 2012-11-28 | 2015-05-20 | 江苏金方圆数控机床有限公司 | Pulse laser drilling device and drilling method thereof |
| CN204603561U (en) * | 2015-05-27 | 2015-09-02 | 广东高聚激光有限公司 | A kind of laser-processing system |
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Application publication date: 20150909 |