Kev tsim thiab kev loj hlob ntawm keyholes:
Keyhole txhais: Thaum cov hluav taws xob irradiance ntau dua 10 ^ 6W / cm ^ 2, qhov saum npoo ntawm cov khoom melts thiab evaporates nyob rau hauv qhov kev txiav txim ntawm laser.Thaum lub evaporation ceev yog loj txaus, lub generated vapor recoil siab yog txaus los kov yeej lub nto nro thiab lub ntiajteb txawj nqus ntawm cov kua hlau, yog li tshem tawm ib co ntawm cov kua hlau, ua rau lub molten pas dej ua ke nyob rau hauv lub excitation cheeb tsam yog dab dej thiab tsim me me pits. ;Lub teeb ntawm lub teeb ncaj qha ua rau hauv qab ntawm lub qhov me me, ua rau cov hlau ntxiv yaj thiab gasify.Kev kub siab chav tseem ua rau cov kua hlau nyob hauv qab ntawm lub qhov kom ntws mus rau qhov chaw ntawm lub pas dej molten, ntxiv rau qhov tob me me.Cov txheej txheem no txuas ntxiv mus, thaum kawg tsim lub qhov tseem ceeb zoo li lub qhov hauv cov kua hlau.Thaum cov hlau vapor siab generated los ntawm lub laser beam nyob rau hauv lub me me mus txog equilibrium nrog lub nto nro thiab lub ntiajteb txawj nqus ntawm cov kua hlau, qhov me me tsis tob thiab tsim ib tug tob ruaj khov lub qhov me me, uas yog hu ua "small qhov nyhuv" .
Raws li lub laser beam txav mus rau lub workpiece, lub qhov me me qhia tau hais tias ib tug me ntsis rov qab nkhaus pem hauv ntej thiab ib tug kom meej inclined inverted daim duab peb sab nyob rau tom qab.Lub pem hauv ntej ntug ntawm lub qhov me me yog qhov chaw ua haujlwm ntawm lub laser, nrog rau qhov kub thiab txias siab, thaum qhov kub ntawm lub nraub qaum yog qhov qis thiab lub vapor siab me me.Nyob rau hauv lub siab thiab kub sib txawv no, cov kua molten ntws nyob ib ncig ntawm lub qhov me me los ntawm lub hauv ntej kawg mus rau sab nraum qab kawg, tsim ib tug vortex nyob rau hauv lub rov qab kawg ntawm lub qhov me me, thiab thaum kawg solidifies ntawm ntug ntug.Lub dynamic lub xeev ntawm lub keyhole tau los ntawm laser simulation thiab tiag welding yog qhia nyob rau hauv daim duab saum toj no, Lub morphology ntawm me me qhov thiab cov ntws ntawm ib puag ncig molten kua thaum mus txawv tebchaws speeds.
Vim muaj cov qhov me me, lub zog ntawm lub zog laser nkag mus rau hauv cov khoom siv sab hauv, tsim qhov sib sib zog nqus thiab nqaim weld seam.Qhov kev sib txawv ntawm cov morphology ntawm lub laser sib sib zog nqus nqus weld seam yog qhia nyob rau hauv daim duab saum toj no.Qhov tob tob ntawm qhov vuam seam yog ze rau qhov tob ntawm lub qhov tseem ceeb (kom meej meej, txheej txheej metallographic yog 60-100um tob dua li qhov keyhole, ib txheej dej tsawg dua).Qhov siab dua lub zog ntawm lub zog laser, qhov tob ntawm qhov me me, thiab qhov tob tob ntawm qhov vuam vuam ntau dua.Nyob rau hauv high-power laser welding, qhov siab tshaj plaws qhov tob rau qhov dav piv ntawm weld seam tuaj yeem ncav cuag 12: 1.
Kev tsom xam ntawm kev nqus ntawmlaser zogntawm keyhole
Ua ntej tsim cov qhov me me thiab ntshav plasma, lub zog ntawm lub laser feem ntau xa mus rau sab hauv ntawm lub workpiece los ntawm thermal conduction.Cov txheej txheem welding belongs rau conductive welding (nrog rau qhov tob tob ntawm tsawg dua 0.5 hli), thiab cov khoom nqus nqus ntawm lub laser yog nyob nruab nrab ntawm 25-45%.Thaum lub keyhole yog tsim, lub zog ntawm lub laser feem ntau absorbed los ntawm lub sab hauv ntawm lub workpiece los ntawm lub keyhole nyhuv, thiab cov txheej txheem welding yuav sib sib zog nqus welding (nrog rau qhov tob tob ntawm ntau tshaj 0.5mm), tus nqi nqus tau mus txog. tshaj 60-90%.
Cov nyhuv keyhole plays lub luag haujlwm tseem ceeb hauv kev txhim kho qhov nqus ntawm laser thaum ua haujlwm xws li laser vuam, txiav, thiab drilling.Lub laser beam nkag mus rau hauv lub qhov tseem ceeb yog yuav luag tag absorbed los ntawm ntau yam reflections los ntawm lub qhov phab ntsa.
Nws yog feem ntau ntseeg hais tias lub zog nqus mechanism ntawm laser nyob rau hauv lub keyhole muaj xws li ob txheej txheem: thim rov qab absorption thiab Fresnel absorption.
Kev sib npaug siab hauv lub qhov tseem ceeb
Thaum lub sij hawm laser sib sib zog nqus welding, cov ntaub ntawv undergoes heev vaporization, thiab expansion siab generated los ntawm high-temperature chav expels cov kua hlau, tsim me me qhov.Ntxiv nrog rau qhov vapor siab thiab ablation siab (tseem hu ua evaporation cov tshuaj tiv thaiv quab yuam lossis recoil siab) ntawm cov khoom, kuj tseem muaj qhov nro saum npoo, cov kua dej zoo li qub los ntawm lub ntiajteb txawj nqus, thiab cov kua dej dynamic siab tsim los ntawm cov khoom siv molten hauv lub qhov me.Ntawm cov kev ntxhov siab no, tsuas yog lub zog siab tswj qhov qhib ntawm lub qhov me me, thaum lwm qhov peb lub zog siv zog kaw lub qhov me me.Txhawm rau kom muaj kev ruaj ntseg ntawm qhov keyhole thaum lub sij hawm vuam txheej txheem, lub vapor siab yuav tsum txaus kom kov yeej lwm yam kev tiv thaiv thiab ua tiav qhov sib npaug, tswj kev ruaj ntseg ntev ntawm lub qhov tseem ceeb.Rau kev yooj yim, nws feem ntau ntseeg tau tias lub zog ua haujlwm ntawm phab ntsa ntawm lub qhov tseem ceeb yog ablation siab (hlau vapor recoil siab) thiab qhov nro.
Instability ntawm Keyhole
Tom qab: Laser ua rau saum npoo ntawm cov ntaub ntawv, ua rau cov hlau ntau ntau kom evaporate.Lub recoil siab nias rau ntawm lub pas dej molten, tsim cov keyholes thiab ntshav, uas ua rau muaj kev nce hauv qhov tob tob.Thaum lub sij hawm ntawm kev txav, lub laser hits pem hauv ntej phab ntsa ntawm lub qhov tseem ceeb, thiab txoj hauj lwm uas lub laser hu rau cov khoom yuav ua rau hnyav evaporation ntawm cov khoom.Nyob rau tib lub sijhawm, cov phab ntsa ntawm lub qhov tseem ceeb yuav muaj kev poob ntau, thiab cov evaporation yuav tsim ib lub zog recoil uas yuav nias rau ntawm cov kua hlau, ua rau cov phab ntsa sab hauv ntawm lub qhov tseem ceeb hloov mus rau hauv qab thiab txav mus rau hauv qab ntawm lub qhov tseem ceeb ntawm lub qhov. rov qab lub pas dej molten.Vim qhov hloov pauv ntawm cov kua dej molten pas dej ua ke los ntawm phab ntsa pem hauv ntej mus rau sab nraum qab phab ntsa, qhov ntim hauv lub qhov tseem ceeb hloov pauv tas li, Lub siab sab hauv ntawm lub qhov tseem ceeb kuj hloov raws li, uas ua rau muaj kev hloov pauv ntawm qhov ntim ntawm cov plasma txau tawm. .Kev hloov pauv hauv cov ntshav plasma ua rau muaj kev hloov pauv hauv kev tiv thaiv, refraction, thiab nqus ntawm lub zog laser, uas ua rau muaj kev hloov pauv ntawm lub zog ntawm lub laser mus txog cov khoom nto.Tag nrho cov txheej txheem yog dynamic thiab periodic, thaum kawg ua rau ib tug sawtooth zoo li tus thiab wavy hlau nkag mus, thiab tsis muaj ib tug du sib npaug zos rau weld, daim duab saum toj no yog ib tug cross-sectional saib ntawm qhov chaw ntawm lub weld tau los ntawm longitudinal txiav thaum uas tig mus. qhov nruab nrab ntawm qhov vuam, nrog rau kev ntsuas lub sijhawm tiag tiag ntawm qhov ntsuas qhov tob qhov sib txawv los ntawmIPG-LDD ua pov thawj.
Txhim kho txoj kev ruaj ntseg ntawm qhov keyhole
Thaum lub sij hawm laser sib sib zog nqus nqus vuam, qhov ruaj khov ntawm lub qhov me me tsuas yog tuaj yeem ua kom ntseeg tau los ntawm qhov sib npaug ntawm ntau yam kev ntxhov siab hauv lub qhov.Txawm li cas los xij, kev nqus ntawm lub zog laser los ntawm lub qhov phab ntsa thiab cov evaporation ntawm cov ntaub ntawv, ejection ntawm hlau vapor sab nraum lub qhov me me, thiab kev txav mus rau pem hauv ntej ntawm lub qhov me me thiab lub pas dej molten yog tag nrho cov txheej txheem ceev heev.Raws li cov txheej txheem txheej txheem, qee lub sijhawm thaum lub sijhawm vuam txheej txheem, nws muaj peev xwm ua kom qhov ruaj khov ntawm lub qhov me me tuaj yeem cuam tshuam rau hauv cov cheeb tsam hauv zos, ua rau cov vuam tsis xws luag.Cov feem ntau raug thiab feem ntau yog me me pore hom porosity defects thiab spatter tshwm sim los ntawm keyhole vau;
Yog li yuav ua li cas stabilize lub keyhole?
Qhov kev hloov pauv ntawm cov kua dej hauv qhov tseem ceeb yog qhov nyuaj thiab muaj ntau yam (kub teb, ntws teb, quab yuam teb, optoelectronic physics), uas tuaj yeem muab faib ua ob pawg: kev sib raug zoo ntawm qhov nro thiab hlau vapor recoil siab;Lub recoil siab ntawm hlau vapor ncaj qha ua rau lub cim ntawm keyholes, uas yog ze ze rau qhov tob thiab ntim ntawm keyholes.Nyob rau tib lub sij hawm, raws li tsuas yog upward txav khoom ntawm hlau vapor nyob rau hauv cov txheej txheem vuam, nws kuj yog ze ze rau qhov tshwm sim ntawm spatter;Nto nro cuam tshuam qhov ntws ntawm lub pas dej molten;
Yog li ruaj khov laser welding txheej txheem nyob ntawm kev tswj xyuas qhov kev faib tawm ntawm qhov nro ntawm lub pas dej molten, tsis muaj qhov hloov pauv ntau dhau.Nto nro muaj feem xyuam rau qhov kub thiab txias, thiab qhov kub thiab txias yog cuam tshuam rau qhov cua sov.Yog li ntawd, cov khoom siv hluav taws xob sib xyaw thiab viav vias vuam yog cov lus qhia muaj peev xwm rau cov txheej txheem vuam ruaj khov;
Cov hlau vapor thiab qhov ntim qhov tseem ceeb yuav tsum tau them sai sai rau cov nyhuv plasma thiab qhov loj ntawm qhov qhib qhov qhib.Qhov loj dua qhov qhib, qhov loj dua qhov keyhole, thiab qhov kev hloov pauv tsis txaus ntseeg nyob rau hauv qab taw tes ntawm lub pas dej yaj, uas muaj qhov cuam tshuam me me rau tag nrho cov keyhole ntim thiab kev hloov hauv siab;Yog li adjustable nplhaib hom laser (annular chaw), laser arc recombination, zaus modulation, thiab lwm yam. yog tag nrho cov lus qhia uas yuav tsum tau nthuav.
Post lub sij hawm: Dec-01-2023
