Meet era of small treatment of leather second laser

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Well-known, laser of leather second pulse in extensive industry small treatment applies a respect to have numerous advantage. What be worth to be carried especially is, it affects an area without heat almost, the material range that can treat is extremely wide, include those is in even the material with visible light and transparent area of close infra-red light. Nevertheless, be in inchoate when, leather second laser still does not have necessary reliability, low management cost, also lack the practice parameter that applies actually in a lot of production environments. And the advantage characteristic that the laser of industrial skin second of new now generation can realize place of this one technology to have. The article discussed accept second and leather second the main difference between laser beam machining, introduced current practicable the basic architecture of source of leather second laser and the representative application in industry. What small treatment of second of accept of leather second Vs is aimed at normally is the treatment demand of micron level, be like aperture and chamfer, avoid to cause fire damage to circumjacent material even at the same time. In other words, the purpose of small treatment wins careful, clean cut namely, and hot influence area (HAZ) the smallest. Undertake accurate bore with laser, delimit piece or cut has two kinds of basic mechanisms. A lot of tradition application basically are relied on infra-red move Q laser with visible light, their arteries and veins is wide in tens of accept second limits, remove material through heating up action to move solely (see a picture 1) . Below this kind of circumstance, the laser light beam of focusing is airtight, the heat source with high intensity, it can heat quickly the vaporization that target material makes finally. The advantage of this kind of method is it OK and fast purify is opposite more target material (move Q laser to this in order to count kilohertz normally especially repeat frequency to move) . And, well-known is technology of accept second laser has perfect technical base, origin height is reliable, operation cost is very charming also. Nevertheless, for the most slashing to those requirements treatment task, the recast material of the size that affects an area in heat, frequent generation or of exterior coating statified the respect such as craze still exists a few limitation. The 2nd kind of mechanism of laser purify material is built in actinic ablation (graph 1) on the foundation. Below this kind of circumstance, laser photon destroys the combinative key of target material directly. This is opposite for be a kind " cold " machine a process, hot influence area is very consequently small. Additional, whole treatment process is very clean, without recast material, need later period rework rarely consequently. Ultraviolet (the high-energy quantity of UV) laser photon is meant in a lot of material they are OK drive is actinic the happening of ablation. Accordingly, laser of Q of violet transfer to other localities comes through actinic ablation purify material. Nevertheless, another method that can implement complete actinic ablation action is the pulse with shorter perhaps course of quantity of use skin second. These exceed short pulse to have power of very high instantaneous peak value (million tile and above) , its are tall energy density makes its can pass much photon to absorb the electron in arouse material and destroy atomic key directly (graph 2) . In addition, because arteries and veins is wide the emissivity that compares machining data is short, the major quantity of heat that leftover fuel factor brings can be taken away, and have not enough time to travel to come, won't generate heat basically to affect an area consequently. Nextpage besides treatment in the process affect an area basically without heat, another when exceed quick treatment main good point is it applicable material range is very wide, include material of a few kinds of broad forbidden band (for example glass and certain polymer) , linear of this kind of material is absorbed and absorb solely very low, because this is very difficult,commercialize laser to handle with what have. Specific for, although these material are in laser wavelengh limits is transmission normally, this one " wavelengh is not knowable " the technology also can be caused nonlinear absorb. At present the limits of the leather second laser on market normally from infra-red arrive ultraviolet. Generally speaking, laser of violet cortical second affects area respect to having first-rate to behave in high accuracy and the smallest heat. Because they are basic,this is it is actinic ablation, and OK still focusing arrives the smallest facula size (through diffraction) . From on the other hand for, infra-red can provide greater output power normally with laser of second of visible light skin, bring higher processing rate thereby. Although architecture of leather second laser is current the industry on market exceeds fast laser varied on form and structure, but they are having same basic configuration. Specifically, will output the pulse with 10 skins shorter perhaps second through the passive oscillation that lock up a model, this is drive the requirement of actinic ablation. However, the pulse that the most oscillator that lock up a model produces is opposite for energy is inferior, repeat frequency to be in tens of megahertz. This one too tall repetition frequency cannot be handled with existing scanning technology, extract the one fraction in these pulse so with pulse selector, magnify next through amplifier the energy of these pulse, undertake final output again. Product of second of most commerce skin is based on one of the following architecture: Fiber-optic oscillator imposes fiber-optic or strong condition fiber-optic amplifier, fiber-optic oscillator adds free space amplifier, oscillator of solid state of diode pump riverside adds free space amplifier. The dominant position that completely fiber-optic oscillator increases amplifier program is cost relatively inferior. A few other effect in insufficient place dispute linear, scattering and fiber-optic amplifier restricted the maximum of unit pulse energy, this number is 10µJ (when pulse of 10 skins second) . Accordingly, the only method that gains high average power rises namely repeat frequency, and law of this one party conducted systematic respect to encounter difficult problem in beam of light, because of mechanism of deflexion of most beam of light, for example Zhenjing scans, not quite fast, overlap in order to avoid individual pulse in workpiece surface. For example, the diameter is the focal facula of 50µm, pulse repeats frequency to be 1MHz, scanning speed needs to achieve 50m/s ability to avoid pulse to overlap, this one speed can be accomplished rarely. The result is to machined processing speed to be restricted. The higher pulse energy that needs to realize much application, can match free space amplifier with fiber-optic oscillator. For example, the Talisker laser of Coherent company used this kind of method. Because the output energy of seminal source is opposite inferior, so need uses second birth amplifier. In second birth amplifier, pulse is magnified greatly, at the same time the function of beam of light and quality are maintained to come down well. Adopt this kind of design, the pulse energy that Talisker laser can provide 180µJ (fall in 1064nm and 200kHz) . The 3rd kind of method is to use oscillator of solid state of semiconductor pump riverside, this kind of method can produce higher pulse energy. It is free space amplifier next, it is second birth amplifier or multistage amplifier normally. In fact, can use many amplifier phase to elevate higher level power. For example, the product that after Coherent company bought Lumera Laser company 2012, acquires is in namely Nd:YOne or more amplifier was joined after VO4 seed source, make the pulse energy of Lumera laser is as high as 200µJ(to be in 1064nm) . Express 1 summary agile modular the greatest average power that after architecture uses one class, two class or 3 class amplifier respectively, can gain. This one product used amplifier of transient state multistage, because it has many advantages below this kind of circumstance,this is. Compare with second birth amplifier especially, transient state amplifier can offer taller repetition frequency, and can more agile ground is adjusted repeat frequency (include to come from odd pulse below this kind of circumstance 2 megahertz) . Another of structure of transient state amplifier very significant advantage is, it supports " pulse strings together mode " operation, namely pulse selector can deliver a string of successive pulse (can amount to 10 normally) , is odd pulse not merely. A string of whole pulse can be magnified in follow-up phase. The advantage of this one mode is, below certain circumstance, it can raise the ablating rate that average laser power leaves some greatly (the quantity of material of purify of every unit time) . For example, the experiment makes clear, when repeating frequency to be 1MH, become a string when 5 pulse pass amplifier, compare with individual pulse photograph, former and OK increase 5 ～ 10 times ablating rate. The average power of the generation below every kinds of circumstance is similar, and actually, the every pulse energy that pulse strings together mode to fall is inferior (because amplifier gain is allocated,arrive in a few pulse) . However, when the span of pulse is lesser, ablating rate depends on not linearly pulse energy. The exact mechanism of ablating rate still is in research, but at present a few get burgeoningly the theory of praise highly. It thinks, only between pulse 20 accept second controls interval when, material does not have time to loosen, still can be in " pretreatment " condition, this makes pulse is strung together in subsequently pulse can realize bigger material purify, although energy is inferior. This mode is OK greatly the parameter space that open up exceeds quick small treatment. The fact proves it to be able to produce the biggest effect on those stuff that have free electron, for example the material such as steel, hard alloy and silicon. And to including pottery and porcelain and glass inside those medium material, its dominant position is very small, do not have basically even. Laser of reliable industrial skin second CNC Milling CNC Machining