Raws li EU's RoHS Directive (Cov Lus Qhia ntawm European Parliament thiab Council ntawm European Union ntawm kev txwv tsis pub siv qee yam khoom siv phom sij hauv cov khoom siv hluav taws xob thiab hluav taws xob), Cov lus qhia yuav tsum tau txwv tsis pub EU ua lag luam muag hluav taws xob thiab Cov khoom siv hluav taws xob uas muaj rau 6 yam phom sij xws li txhuas raws li "kev tsim ntsuab" cov txheej txheem tsis muaj cov hmoov lead uas tau dhau los ua qhov kev txhim kho tsis tuaj yeem txij li Lub Xya Hli 1, 2006.
Nws tau muaj ntau tshaj li ob xyoos txij li cov txheej txheem tsis muaj txhuas pib los ntawm theem kev npaj.Ntau cov khoom siv hluav taws xob hauv Suav teb tau sau ntau qhov kev paub tseem ceeb hauv kev hloov pauv ntawm cov hlau lead-dawb soldering mus rau cov hlau lead-dawb soldering.Tam sim no hais tias cov txheej txheem tsis muaj hmoov txhuas tau dhau los ua neeg paub tab, kev ua haujlwm ntawm cov tuam txhab feem ntau tau hloov pauv los ntawm tsuas yog tuaj yeem siv cov khoom tsis muaj hmoov txhuas mus rau kev txhim kho qib ntawm cov hlau lead-dawb soldering los ntawm ntau yam xws li khoom siv. , cov ntaub ntawv, zoo, txheej txheem thiab lub zog noj..
Cov txheej txheem tsis muaj cov hlau lead-dawb reflow soldering yog cov txheej txheem tseem ceeb tshaj plaws nyob rau hauv cov txheej txheem saum npoo av tam sim no.Nws tau siv dav hauv ntau qhov kev lag luam xws li xov tooj ntawm tes, khoos phis tawj, automotive electronics, tswj circuits thiab kev sib txuas lus.Ntau thiab ntau cov khoom siv hluav taws xob qub tau hloov pauv los ntawm lub qhov mus rau qhov chaw mount, thiab reflow soldering hloov yoj soldering nyob rau hauv ib qho kev txiav txim siab yog qhov pom tseeb hauv kev lag luam soldering.
Yog li dab tsi lub luag haujlwm yuav rov ua cov khoom siv rov ua dua tshiab hauv cov txheej txheem SMT tsis muaj hlau lead?Cia peb saib nws los ntawm qhov kev xav ntawm tag nrho SMT nto mount kab:
Tag nrho SMT nto mount kab feem ntau muaj peb ntu: tshuab luam ntawv tshuaj ntsuam, tso tshuab thiab reflow qhov cub.Rau cov tshuab tso kawm, piv nrog cov hlau lead-dawb, tsis muaj qhov xav tau tshiab rau cov khoom siv nws tus kheej;Rau lub tshuab luam ntawv tshuaj ntsuam, vim qhov sib txawv me ntsis ntawm cov khoom siv lub cev ntawm cov hlau lead-dawb thiab cov hlau lead solder paste, qee qhov kev txhim kho yuav tsum tau muab tso rau pem hauv ntej rau cov khoom siv nws tus kheej, tab sis tsis muaj qhov hloov pauv zoo;Qhov kev sib tw ntawm cov hlau lead-dawb siab yog precisely ntawm lub qhov cub reflow.
Raws li koj paub, lub melting point ntawm txhuas solder paste (Sn63Pb37) yog 183 degrees.Yog tias koj xav tsim kom muaj kev sib koom tes zoo, koj yuav tsum muaj 0.5-3.5um thickness ntawm intermetallic compounds thaum lub sij hawm soldering.Qhov kub ntawm qhov sib txuas ntawm intermetallic yog 10-15 degrees saum lub melting point, uas yog 195-200 rau leaded soldering.degree.Qhov siab tshaj plaws ntawm cov khoom siv hluav taws xob qub ntawm lub rooj tsav xwm Circuit Court yog feem ntau 240 degrees.Yog li ntawd, rau cov hlau lead, qhov zoo tshaj plaws soldering txheej txheem qhov rais yog 195-240 degrees.
Cov hlau lead-dawb soldering tau coj cov kev hloov pauv zoo rau cov txheej txheem soldering vim tias qhov melting point ntawm cov hlau lead-free solder paste tau hloov.Tam sim no feem ntau siv lead-free solder paste yog Sn96Ag0.5Cu3.5 nrog lub melting point ntawm 217-221 degrees.Zoo txhuas-dawb soldering yuav tsum tau tsim intermetallic tebchaw nrog ib tug tuab ntawm 0.5-3.5um.Qhov tsim kub ntawm intermetallic tebchaw kuj yog 10-15 degrees saum lub melting point, uas yog 230-235 degrees rau cov hlau lead-free soldering.Txij li thaum qhov kub siab tshaj plaws ntawm cov hlau lead-dawb soldering hluav taws xob cov khoom qub tsis hloov, qhov zoo tshaj plaws ntawm cov txheej txheem soldering qhov rais rau cov hlau tsis muaj hlau yog 230-240 degrees.
Kev txo qis ntawm cov txheej txheem qhov rais tau coj cov teeb meem loj los lav qhov vuam zoo, thiab kuj tau coj cov kev xav tau ntau dua rau kev ruaj ntseg thiab kev ntseeg siab ntawm cov khoom siv tsis muaj hlau lead.Vim yog qhov sib txawv ntawm qhov sib txawv ntawm cov khoom siv nws tus kheej, thiab qhov sib txawv ntawm lub peev xwm thermal ntawm cov khoom siv hluav taws xob qub thaum lub sij hawm cua sov, cov txheej txheem kub ntawm qhov rais qhov rais uas tuaj yeem hloov kho hauv cov txheej txheem tsis muaj cov hlau lead-dawb reflow soldering kev tswj ua me me heev. .Qhov no yog qhov nyuaj tiag tiag ntawm cov hlau lead-dawb reflow soldering.Qhov tshwj xeeb cov hlau lead-dawb thiab tsis muaj hlau lead-dawb reflow soldering txheej txheem qhov rai sib piv yog qhia hauv daim duab 1.
Hauv cov ntsiab lus, lub qhov cub reflow plays lub luag haujlwm tseem ceeb hauv qhov kawg ntawm cov khoom zoo los ntawm kev xav ntawm tag nrho cov txheej txheem tsis muaj txhuas.Txawm li cas los xij, los ntawm qhov kev xav ntawm kev nqis peev hauv tag nrho SMT cov kab ntau lawm, kev nqis peev hauv cov khoom siv hluav taws xob tsis muaj hlau lead feem ntau tsuas yog tso nyiaj rau 10-25% ntawm kev nqis peev hauv tag nrho SMT kab.Qhov no yog vim li cas ntau lub tuam txhab hluav taws xob tam sim ntawd hloov lawv qhov qub reflow ncu nrog qhov zoo dua reflow ncu tom qab hloov mus rau cov khoom tsis muaj hlau lead.
Post lub sij hawm: Aug-10-2020