I-Reflow soldering iyinqubo lapho i-solder paste (ingxube enamathelayo ye-solder eyimpuphu kanye ne-flux) isetshenziselwa ukunamathisela okwesikhashana ingxenye eyodwa noma eziningana zikagesi kuma-pads abo okuxhumana, ngemva kwalokho yonke inhlangano ingaphansi kokushisa okulawulwayo, okuncibilikisa i-solder. , ukuxhuma unomphela isihlanganisi.Ukushisa kungase kufezwe ngokudlulisela umhlangano kuhhavini ogeleza kabusha noma ngaphansi kwesibani se-infrared noma ngokuhlanganisa amalunga ngamanye ngepensela yomoya oshisayo.
I-Reflow soldering iyindlela evamile kakhulu yokunamathisela izingxenye ze-surface mount ebhodini lesifunda, nakuba ingase isetshenziselwe izingxenye zembobo ngokugcwalisa izimbobo nge-solder paste bese ufaka ingxenye ehamba phambili ngokusebenzisa unamathisele.Ngenxa yokuthi i-wave soldering ingaba lula futhi ishibhile, ukugeleza kabusha akuvamile ukusetshenziswa emabhodini ahlanzekile emigodini.Uma isetshenziswa emabhodini aqukethe inhlanganisela yezingxenye ze-SMT ne-THT, ukugeleza kabusha kwe- through-hole kuvumela isinyathelo sokusongelisa igagasi ukuthi sisuswe enqubweni yokuhlanganisa, okungenzeka kunciphise izindleko zokuhlanganisa.
Umgomo wenqubo yokugeleza kabusha ukuncibilikisa i-solder nokushisa izindawo eziseduze, ngaphandle kokushisa ngokweqile nokulimaza izingxenye zikagesi.Enqubweni evamile yokudayiswa kwe-reflow soldering, ngokuvamile kunezigaba ezine, ezibizwa ngokuthi "izindawo", ngasinye sinephrofayili ehlukile yokushisa: ukushisa kwangaphambili, ukucwiliswa kwe-thermal (okuvame ukufushaniswa ukuze kuvele ukucwiliswa), ukugeleza kabusha, nokupholisa.
Preheat zone
Umkhawulo wemithambeka ubudlelwano bezinga lokushisa/isikhathi obukala ukuthi izinga lokushisa ebhodini lesekethe eliphrintiwe lishintsha ngokushesha kangakanani.Indawo yokushisa ngaphambi kwesikhathi ivamise ukuba yinde kakhulu ezindaweni futhi ivamise ukusungula isilinganiso serempu.Izinga le-ramp-up ngokuvamile liphakathi kuka-1.0 °C no-3.0 °C ngesekhondi, ngokuvamile lehla phakathi kuka-2.0 °C no-3.0 °C (4 °F kuya ku-5 °F) ngomzuzwana.Uma izinga lidlula i-slope esiphezulu, ukulimala kwezingxenye ezivela ekushaqekeni okushisayo noma ukuqhekeka kungenzeka.
I-solder paste ingaba nomthelela wokufafaza.Isigaba sokushisa kuqala lapho i-solvent ekunamathisele iqala ukuhwamuka, futhi uma izinga lokukhuphuka (noma izinga lokushisa) liphansi kakhulu, ukuhwamuka kwe-flux volatiles akuphelele.
Indawo yokushisa eshisayo
Ingxenye yesibili, i-thermal soak, ngokuvamile iwukuchayeka kwesekhondi elingu-60 kuya kwezingu-120 ukuze kukhishwe izivunguvungu ze-solder paste kanye nokwenza kusebenze ukuguquguquka (bona i-flux), lapho izingxenye ze-flux ziqala ukuncishiswa kwe-oxide ezingxenyeni zokuhola namaphedi.Izinga lokushisa eliphakeme kakhulu lingaholela ekuchithekeni kwe-solder noma ekubholeni kanye ne-oxidation ye-paste, amaphedi okunamathiselwe kanye nokuqedwa kwengxenye.
Ngokufanayo, ama-fluxes angase angasebenzi ngokugcwele uma izinga lokushisa liphansi kakhulu.Ekupheleni kwendawo yokucwilisa ukulingana okushisayo kwayo yonke inhlangano kuyadingeka ngaphambi nje kwendawo yokugeleza kabusha.Iphrofayili yokucwilisa iphakanyiswa ukuthi yehlise noma iyiphi i-delta T phakathi kwezingxenye zosayizi abahlukahlukene noma uma umhlangano we-PCB mkhulu kakhulu.Iphrofayili ye-soak nayo iyanconywa ukuthi inciphise ukuvama endaweni yamaphakheji ohlobo lwendawo.
Indawo yokugeleza kabusha
Ingxenye yesithathu, indawo yokugeleza kabusha, ibizwa nangokuthi "isikhathi esingaphezulu kokugeleza kabusha" noma "isikhathi esingaphezu kwe-liquidius" (TAL), futhi siyingxenye yenqubo lapho izinga lokushisa eliphezulu lifinyelelwa khona.Ukucatshangelwa okubalulekile izinga lokushisa eliphakeme, okuyizinga lokushisa eliphakeme elivumelekile layo yonke inqubo.Izinga lokushisa eliphakeme elivamile liyi-20-40 ° C ngaphezu kwe-liquidus.Lo mkhawulo unqunywa ingxenye esembuthanweni ngokubekezelela okuphansi kwamazinga okushisa aphezulu (Ingxenye esengozini kakhulu ekulimaleni okushisayo).Umhlahlandlela ojwayelekile uwukukhipha u-5 °C ezingeni lokushisa eliphezulu elingagcinwa ingxenye esengozini kakhulu ukuze ifike ezingeni eliphezulu lokushisa ukuze kucutshungulwe.Kubalulekile ukuqapha izinga lokushisa lenqubo ukuze lingadluli lo mkhawulo.
Ukwengeza, amazinga okushisa aphezulu (ngaphezu kuka-260 °C) angabangela ukulimala kwangaphakathi kokufa kwezingxenye ze-SMT kanye nokukhuthaza ukukhula kwe-intermetallic.Ngokuphambene, izinga lokushisa elingashisi ngokwanele lingavimbela ukunamathisela ekugelezeni kabusha ngokwanele.
Isikhathi esingaphezulu kwe-liquidius (TAL), noma isikhathi esingaphezulu kokugeleza kabusha, sikala ukuthi i-solder iwuketshezi isikhathi esingakanani.I-flux inciphisa ukungezwani kwendawo lapho kuhlangana khona izinsimbi ukuze kufezeke ukuhlangana kwe-metallurgical, okuvumela ama-solder powder spheres ukuthi ahlangane.Uma isikhathi sephrofayili sidlula ukucaciswa komkhiqizi, umphumela ungaba ukuqalisa ukusebenza kwe-flux ngaphambi kwesikhathi noma ukusetshenziswa, ngokuphumelelayo "ukoma" ukunamathisela ngaphambi kokwakhiwa kwejoyinti le-solder.Ubudlelwane besikhathi/izinga lokushisa obanele bubangela ukwehla kwesenzo sokuhlanza i-flux, okuholela ekumanzini kabi, ukukhishwa okunganele kwe-solvent kanye ne-flux, kanye namajoyinti e-solder okungenzeka angasebenzi.
Ochwepheshe ngokuvamile batusa i-TAL emfushane kakhulu ngangokunokwenzeka, nokho, ukunamathisela okuningi kucacisa i-TAL encane yamasekhondi angu-30, nakuba kubonakala kungenasizathu esicacile saleso sikhathi esithile.Okunye okungenzeka ukuthi kunezindawo ku-PCB ezingakalwa ngesikhathi sokuphrofayili, ngakho-ke, ukubeka ubuncane besikhathi esivumelekile kumasekhondi angama-30 kunciphisa amathuba okuthi indawo engakaliwe ingaphinde igeleze.Isikhathi esincane esiphezulu sokugeleza kabusha sinikeza umkhawulo wokuphepha ngokumelene nezinguquko zokushisa kuhhavini.Isikhathi sokumanzisa sihlala singaphansi kwamasekhondi angama-60 ngaphezu kwe-liquidus.Isikhathi esengeziwe esingaphezulu kwe-liquid singase sibangele ukukhula kwe-intermetallic ngokweqile, okungaholela ekulimaleni kwamalunga.Ibhodi nezingxenye kungase konakaliswe ngezikhathi ezinwetshiwe ngaphezu kwe-liquidus, futhi izingxenye eziningi zinomkhawulo wesikhathi ochazwe kahle wokuthi zingase zivezwe isikhathi esingakanani emazingeni okushisa ngaphezu komkhawulo othile.
Isikhathi esincane kakhulu ngaphezu kwe-liquid singase sibambe izincibilikisi kanye nokuguquguquka futhi kudale amathuba okuba amalunga abandayo noma abuthuntu kanye nama-solder voids.
Indawo yokupholisa
Indawo yokugcina iyindawo yokupholisa ukuze upholise kancane kancane ibhodi elicutshunguliwe futhi uqinise amalunga e-solder.Ukupholisa okufanele kuvimbela ukwakheka kwe-intermetallic ngokweqile noma ukushaqeka okushisayo ezingxenyeni.Amazinga okushisa ajwayelekile endaweni yokupholisa asukela ku-30–100 °C (86–212 °F).Izinga lokupholisa elisheshayo likhethwa ukuze kwakhiwe ukwakheka okuhle okusanhlamvu okuzwakala kahle ngomshini.
[1] Ngokungafani nesilinganiso esiphezulu sokunyuka, izinga lokuphuma kwerempu ngokuvamile azinakwa.Kungenzeka ukuthi izinga lerempu libaluleke kakhulu ngaphezu kwamazinga okushisa athile, nokho, umkhawulo ophakeme owehlayo ovumelekile wanoma iyiphi ingxenye kufanele usebenze noma ngabe ingxenye iyashisisa noma ipholisa phansi.Izinga lokupholisa elingu-4°C/s livame ukuphakanyiswa.Ipharamitha okufanele icatshangelwe lapho kuhlaziywa imiphumela yenqubo.
Igama elithi "reflow" lisetshenziselwa ukubhekisela ezingeni lokushisa ngaphezu kwalokho inqwaba eqinile ye-solder alloy ngokuqinisekile izoncibilika (ngokuphambene nokumane kuthambe).Uma ipholile ngaphansi kwalokhu kushisa, i-solder ngeke igeleze.Ukufudumala ngaphezu kwayo futhi, i-solder izogeleza futhi-ngakho "iphinde igeleze".
Izindlela zanamuhla zomhlangano wesifunda ezisebenzisa i-reflow soldering azivumeli ukuthi i-solder igeleze izikhathi ezingaphezu kwesisodwa.Baqinisekisa ukuthi i-solder ene-granulated equkethwe ku-solder paste idlula izinga lokushisa lokugeleza kabusha kwe-solder ehilelekile.
Iphrofayili eshisayo
Ukumelwa okuyisithombe Kwenkomba Yewindi Lenqubo yephrofayela eshisayo.
Embonini yokukhiqiza izinto zikagesi, isilinganiso sezibalo, esaziwa ngokuthi I-Process Window Index (PWI) sisetshenziselwa ukulinganisa ukuqina kwenqubo yokushisa.I-PWI isiza ukukala ukuthi inqubo "ingena" kahle kangakanani emkhawulweni wenqubo echazwe umsebenzisi owaziwa ngokuthi Umkhawulo Wokucaciswa.Iphrofayela ngayinye eshisayo ibalwa ngokuthi "ingena" kanjani ewindini lenqubo (incazelo noma umkhawulo wokubekezelela).
Indawo emaphakathi yewindi lenqubo ichazwa njengoziro, futhi umkhawulo owedlulele wewindi lenqubo njengo-99%.I-PWI enkulu noma elingana no-100% ibonisa ukuthi iphrofayela ayicubunguli umkhiqizo ngaphakathi kokucaciswa.I-PWI engu-99% ikhombisa ukuthi iphrofayili icubungula umkhiqizo ngaphakathi kokucaciswa, kodwa isebenza emaphethelweni ewindi lenqubo.I-PWI yama-60% ikhombisa ukuthi iphrofayili isebenzisa u-60% wenqubo ebekiwe.Ngokusebenzisa amanani e-PWI, abakhiqizi banganquma ukuthi ingakanani iwindi lenqubo elisetshenziswa iphrofayili ethile eshisayo.Inani eliphansi le-PWI libonisa iphrofayela eqinile.
Ukuze usebenze kahle kakhulu, amanani e-PWI ahlukene abalwa ukuze afinyelele ukuphakama, ukuthambeka, ukugeleza kabusha, kanye nezinqubo zokucwilisa zephrofayili eshisayo.Ukuze ugweme ukuthi kungenzeka ukushaqeka okushisayo kuthinte okukhiphayo, umqansa omkhulu kuphrofayili yokushisa kufanele unqunywe futhi ulinganiswe.Abakhiqizi basebenzisa isofthiwe eyakhelwe ngokwezifiso ukuze banqume ngokunembile futhi behlise ukukhuphuka komqansa.Ngaphezu kwalokho, isofthiwe iphinda ilinganise ngokuzenzakalelayo amanani e-PWI okuphakama, ukuthambeka, ukugeleza kabusha, kanye nezinqubo zokucwilisa.Ngokusetha amanani e-PWI, onjiniyela bangaqinisekisa ukuthi umsebenzi we-reflow soldering awushisi ngokweqile noma uphole ngokushesha kakhulu.
Isikhathi sokuthumela: Mar-01-2022