I-Reflow soldering yinkqubo apho i-solder paste (umxube oncangathi we-solder kunye ne-flux) isetyenziselwa ukudibanisa okwethutyana into enye okanye ezininzi zombane kwiipads zabo zoqhagamshelwano, emva koko yonke indibano iphantsi kobushushu obulawulwayo, obunyibilikisa i-solder. , ukudibanisa ngokusisigxina ukudibanisa.Ukufudumala kunokufezekiswa ngokugqithisa i-asembly kwi-oven yokubuyisela kwakhona okanye phantsi kwesibane se-infrared okanye ngokusondeza amajoyinti ngamanye ngepensile yomoya oshushu.
I-Reflow soldering yeyona ndlela ixhaphakileyo yokuncamathisela amacandelo omgangatho wokunyuka kwibhodi yesekethe, nangona ingasetyenziselwa amacandelo emingxuma ngokuzalisa imingxuma nge-solder paste kunye nokufaka icandelo elikhokelela kwi-paste.Ngenxa yokuba i-wave soldering inokuba lula kwaye inexabiso eliphantsi, ukutyhutyha kwakhona akudli ngokusetyenziswa kwiibhodi ezicwengileyo.Xa isetyenziswe kwiibhodi eziqulethe umxube we-SMT kunye ne-THT, i-reflow-hole reflow ivumela ukuba inyathelo le-wave soldering lipheliswe kwinkqubo yokuhlanganisana, okunokunciphisa iindleko zendibano.
Injongo yenkqubo yokubuyisela kwakhona kukunyibilikisa i-solder kunye nokufudumala iindawo ezidibeneyo, ngaphandle kokugqithisa kunye nokonakalisa amacandelo ombane.Kwinkqubo yesiqhelo yokuphinda kuthengiswe, kuhlala kukho izigaba ezine, ezibizwa ngokuba “zizowuni”, ngalinye lineprofayile ye-thermal eyahlukileyo: i-preheat, i-thermal soak (ehlala imfutshane ukufunxa nje), ukuqukuqela kwakhona, kunye nokupholisa.
Indawo yokutshisa kwangaphambili
Ubuninzi bethambeka bubudlelwane bexesha lobushushu / ixesha elilinganisa ukuba ubushushu kwibhodi yesekethe eprintiweyo butshintsha kangakanani.Indawo yokufudumeza kuqala idla ngokuba ngowona mde wezowuni kwaye ihlala iseka ireyithi yerempu.Ireyithi yokunyuka kwenyuka ikholisa ukuba kwindawo ethile phakathi kwe-1.0 °C kunye ne-3.0 °C ngesekhondi, kaninzi iwela phakathi kwe-2.0 °C kunye ne-3.0 °C (4 °F ukuya ku-5 °F) ngesekhondi.Ukuba izinga lidlula i-slope ephezulu, umonakalo kumacandelo avela kwi-thermal shock okanye ukuqhekeka kunokwenzeka.
I-solder paste ingaba nefuthe lokutshiza.Icandelo le-preheat kulapho i-solvent kwi-paste iqala ukukhupha, kwaye ukuba izinga lokunyuka (okanye izinga lokushisa) liphantsi kakhulu, i-evaporation ye-flux volatiles ayiphelelanga.
Indawo yokufunxa iThermal
Icandelo lesibini, i-thermal soak, ngokuqhelekileyo i-60 ukuya kwi-120 ye-exposure yesibini yokususwa kwe-solder paste volatiles kunye nokusebenza kwe-flux (jonga i-flux), apho i-flux components iqala ukuncitshiswa kwe-oxide kwi-component lead and pads.Ukushisa okuphezulu kakhulu kunokukhokelela kwi-solder yokutshiza okanye i-balling kunye ne-oxidation ye-paste, i-attachment pads kunye nokupheliswa kwecandelo.
Ngokufanayo, i-fluxes ayinakusebenza ngokupheleleyo ukuba ubushushu buphantsi kakhulu.Ekupheleni kwendawo yokufunxa i-thermal equilibrium yendibano yonke iyafunwa ngaphambi nje kommandla wokubuyisela kwakhona.Iprofayile yesoki iyacetyiswa ukuba yehlise nayiphi na i-delta T phakathi kwamacandelo obungakanani obahlukeneyo okanye ukuba indibano yePCB inkulu kakhulu.Iprofayile yesoak ikwacetyiswa ukuba icuthe i-voiding kwindawo yohlobo lweepakethe.
Indawo yokuqhubela phambili
Icandelo lesithathu, indawo yokubuyisela kwakhona, ikwabizwa ngokuba "ixesha elingaphezulu kwe-reflow" okanye "ixesha elingaphezulu kwe-liquidius" (TAL), kwaye inxalenye yenkqubo apho ubushushu obuninzi bufikelelwa khona.Ukuqwalaselwa okubalulekileyo kubushushu obuphezulu, obuphezulu obuvumelekileyo benkqubo yonke.Iqondo lokushisa eliqhelekileyo liyi-20-40 ° C ngaphezu kwe-liquid. Lo mda unqunywe yicandelo kwindibano kunye nokunyamezela okuphantsi kwamaqondo aphezulu (Icandelo elithintekayo kakhulu kumonakalo we-thermal).Isikhokelo esisemgangathweni kukuthabatha i-5 °C kubushushu obuphezulu obunokugcinwa kwelona candelo lisemngciphekweni ukuze lifike kowona bushushu uphezulu ukulungiselela inkqubo.Kubalulekile ukujonga ubushushu benkqubo ukuyigcina ingagqithisi kulo mda.
Ukongeza, amaqondo obushushu aphezulu (ngaphaya kwe-260 °C) anokubangela umonakalo kwi-internal dies yamacandelo e-SMT kunye nokukhuthaza ukukhula kwe-intermetallic.Kwelinye icala, iqondo lobushushu elingatshisi ngokwaneleyo linokuthintela intlama ekuphindeni iphume ngokwaneleyo.
Ixesha elingaphezu kwe-liquidius (TAL), okanye ixesha elingaphezu kwe-reflow, lilinganisa ixesha elingakanani i-solder ilulwelo.I-flux inciphisa ukuxinezeleka komphezulu kwindawo ekudityaniswa kuyo isinyithi ukuze kuphunyezwe i-metallurgical bonding, ivumela i-solder powder spheres ukuba idibanise.Ukuba ixesha leprofayili lidlula ukucaciswa komenzi, umphumo unokuba yi-activation flux activation okanye ukusetyenziswa, ngokufanelekileyo "ukomisa" i-paste ngaphambi kokubunjwa kwe-solder joint.Ubudlelwane bexesha / lobushushu obungonelanga bubangela ukuhla kwesenzo sokucoca, okubangela ukumanzisa okungahambi kakuhle, ukukhutshwa okunganelanga kwe-solvent kunye ne-flux, kwaye mhlawumbi i-solder joints enesiphako.
Iingcali zihlala zicebisa eyona TAL imfutshane kunokwenzeka, nangona kunjalo, uninzi lweepasti luchaza ubuncinci be-TAL yemizuzwana engama-30, nangona kubonakala kungekho sizathu sicacileyo selo xesha lithile.Enye into enokwenzeka kukuba kukho iindawo kwi-PCB ezingalinganiswanga ngexesha lokwenziwa kweprofayili, kwaye ke, ukuseta ubuncinci bexesha elivumelekileyo ukuya kwimizuzwana engama-30 kunciphisa amathuba okuba indawo engenakulinganiswa ingaphinde iqukuqele.Ubuncinci bexesha lokuhamba kwakhona libonelela ngomda wokhuseleko ngokuchasene nokutshintsha kobushushu be-oveni.Ixesha lokumanzisa lihlala ngaphantsi kwemizuzwana engama-60 ngaphezulu kolwelo.Ixesha elongeziweyo ngaphezulu kwe-liquidus linokubangela ukukhula okugqithisileyo kwe-intermetallic, okunokukhokelela kukuqina kwamalungu.Ibhodi kunye namacandelo nawo angonakala ngamaxesha awandisiweyo ngaphezulu kolwelo, kwaye uninzi lwamalungu anomda wexesha ochaziweyo wexesha elingakanani anokuthi abonakale kumaqondo obushushu ngaphezulu kobuninzi obunikiweyo.
Ixesha elincinane kakhulu ngaphezu kwe-liquidus linokuthi libambe izinyibilikisi kunye nokuguquguquka kwaye zenze ukubakhona kwamalungu abandayo okanye abuthuntu kunye ne-solder voids.
Indawo yokupholisa
Indawo yokugqibela yindawo yokupholisa ngokuthe ngcembe ukupholisa ibhodi esetyenzisiweyo kunye nokuqinisa amalunga e-solder.Ukupholisa okufanelekileyo kuthintela ukubunjwa okugqithisileyo kwe-intermetallic okanye ukutshatyalaliswa kwe-thermal kumacandelo.Amaqondo obushushu aqhelekileyo kwindawo yokupholisa aqala kwi-30–100 °C (86–212 °F).Isantya sokupholisa ngokukhawuleza sikhethwa ukwenza ulwakhiwo oluhle lweenkozo oluvakala kakhulu ngoomatshini.
[1] Ngokungafaniyo nowona mlinganiselo uphezulu wokunyuka unyuka, izinga lokunyuka ukuya ezantsi lihlala lingahoywa.Kungenzeka ukuba ireyithi yerempu ayibalulekanga kangako ngaphezu kwamaqondo obushushu athile, nangona kunjalo, owona mthambeka uphezulu uvumelekileyo walo naliphi na ilungu kufuneka usetyenziswe nokuba icandelo liyafudumeza okanye liyapholisa.Izinga lokupholisa lika-4°C/s lidla ngokucetyiswa.Yiparameter ekufuneka iqwalaselwe xa kuhlalutywa iziphumo zenkqubo.
Igama elithi "reflow" lisetyenziselwa ukubhekisa kwiqondo lobushushu elingaphezulu apho i-solder mass of solder alloy ngokuqinisekileyo iya kunyibilika (ngokuchaseneyo nokuthambisa nje).Ukuba ipholile ngaphantsi kobu bushushu, i-solder ayiyi kuhamba.Ukufudumala ngaphezulu kwayo kwakhona, i-solder iya kuphinda iphinde iphinde iphinde iphinde iphinde iphinde iphinde "iphinde iphinde iqukuqele".
Iindlela zale mihla zendibano yesiphaluka ezisebenzisa i-reflow soldering azivumeli ukuba i-solder ihambe ngaphezu kwesinye.Baqinisekisa ukuba i-solder ye-granulated equlethwe kwi-solder paste idlula ubushushu bokubuyisela kwakhona kwi-solder echaphazelekayo.
Iprofayile yobushushu
Umboniso womzobo weNkqubo yeSilathiso sefestile yeprofayile yobushushu.
Kwishishini lokuvelisa i-electronics, i-statistical measure, eyaziwa ngokuba yi-Process Window Index (PWI) isetyenziselwa ukulinganisa ukuqina kwenkqubo ye-thermal.I-PWI inceda ukulinganisa indlela inkqubo "engena ngayo" kumda wenkqubo echazwe ngumsebenzisi eyaziwa ngokuba yi-Specification Limit.Iprofayili nganye ye-thermal ibekwe ngendlela "engena ngayo" kwifestile yenkqubo (inkcazo okanye umda wokunyamezela).
Umbindi wefestile yenkqubo ichazwa njenge-zero, kwaye umgca ogqithiseleyo wefestile yenkqubo njenge-99%. I-PWI enkulu okanye ilingana ne-100% ibonisa ukuba iphrofayili ayiqhubeki imveliso ngaphakathi kwenkcazo.I-PWI ye-99% ibonisa ukuba iprofayili iqhuba imveliso ngaphakathi kwenkcazo, kodwa iqhuba ekupheleni kwefestile yenkqubo.I-PWI ye-60% ibonisa ukuba iprofayili isebenzisa i-60% yenkcazo yenkqubo.Ngokusebenzisa ixabiso le-PWI, abavelisi banokumisela ukuba ingakanani inkqubo yefestile esetyenziswa yiprofayili ethile ye-thermal.Ixabiso eliphantsi le-PWI libonisa iprofayile eyomelele ngakumbi.
Ukuphumelela okuphezulu, amaxabiso ahlukeneyo e-PWI abalwa kwincopho, ithambeka, ukutyhutyha kwakhona, kunye neenkqubo zokufunxa zeprofayili ye-thermal.Ukunqanda ukothuka okunokwenzeka okuchaphazela imveliso, elona thambeka liphezulu kwiprofayili ye-thermal kufuneka limiselwe kwaye lilinganiswe.Abavelisi basebenzisa isoftware eyakhelwe-ngokwezifiso ukumisela ngokuchanekileyo kunye nokunciphisa ukuthambeka kwethambeka.Ukongeza, isoftware iphinda ihlengahlengise ngokuzenzekelayo amaxabiso e-PWI encopho, ithambeka, ukuqukuqela kwakhona, kunye neenkqubo zokufunxa.Ngokuseta amaxabiso e-PWI, iinjineli zinokuqinisekisa ukuba umsebenzi wokuphinda uthengiselwe ubushushu awugqithisi okanye uphole ngokukhawuleza.
Ixesha lokuposa: Mar-01-2022