I-SMT( Umhlangano Webhodi Lesifunda Ephrintiwe , PCBA ) ibizwa nangokuthi ubuchwepheshe bokukhuphuka komhlaba.Phakathi nenqubo yokukhiqiza, i-solder paste iyashiswa futhi incibilike endaweni yokushisa, ukuze amaphedi e-PCB ahlanganiswe ngokuthembekile nezingxenye ze-surface mount ngokusebenzisa i-solder paste alloy.Le nqubo siyibiza ngokuthi i-reflow soldering.Iningi lamabhodi esekethe lithambekele ekugobeni nasekujikeni lapho enziwa i-Reflow (reflow soldering).Ezimweni ezimbi kakhulu, kungase kubangele ngisho nezingxenye ezifana ne-solder engenalutho namatshe amathuna. Emgqeni wokuhlanganisa othomathikhi, uma i-PCB yefekthri yebhodi lesifunda ingekho flat, izobangela ukuma okungalungile, izingxenye azikwazi ukufakwa emigodini kanye nama-surface mount pads ebhodi, ngisho nomshini wokufaka othomathikhi uzolimala.Ibhodi elinezingxenye ligobile ngemva kokushisela, futhi izinyawo zengxenye zinzima ukusika kahle.Ibhodi alikwazi ukufakwa ku-chassis noma isokhethi ngaphakathi komshini, ngakho-ke kuyacasula kakhulu ukuthi isitshalo somhlangano sihlangabezane ne-warping yebhodi.Njengamanje, amabhodi aphrintiwe angenile enkathini yokukhwezwa komhlaba kanye nokufakwa kwe-chip, futhi izitshalo zomhlangano kufanele zibe nezidingo eziqinile neziqinile zokungqubuzana kwebhodi.
Ngokusho kwe-US IPC-6012 (Ushicilelo luka-1996) "Ukucaciswa nokucaciswa kokusebenza kwe Amabhodi Aphrintiwe Aqinile ", i-warpage ephezulu evunyelwe kanye nokuhlanekezela kwamabhodi aphrintiwe abekwe phezulu ngu-0.75%, kanye no-1.5% kwamanye amabhodi. Uma kuqhathaniswa ne-IPC-RB-276 (uhlelo luka-1992), lokhu kuthuthukise izimfuneko zamabhodi aphrintiwe abekwe phezulu. okwamanje, i-warpage evunyelwe izitshalo zokuhlanganisa ze-elekthronikhi ezihlukahlukene, kungakhathaliseki ukuthi izinhlangothi ezimbili noma izendlalelo eziningi, ukujiya okungu-1.6mm, kuvame ukuba ngu-0.70~0.75%.
Kumabhodi amaningi e-SMT nawe-BGA, imfuneko ingu-0.5%.Ezinye izimboni ze-elekthronikhi zikhuthaza ukuthi kwenyuswe izinga le-warpage libe ngu-0.3%.Indlela yokuhlola i-warpage ihambisana ne-GB4677.5-84 noma i-IPC-TM-650.2.4.22B.Faka ibhodi eliphrintiwe endaweni eqinisekisiwe, faka iphinikhodi yokuhlola endaweni lapho izinga le-warpage lilikhulu kakhulu, bese uhlukanisa ububanzi bephinikhodi yokuhlola ngobude bonqenqema olugobile lwebhodi eliphrintiwe ukuze ubale i-warpage ye-warpage. ibhodi ephrintiwe.Ijika alisekho.
Ngakho-ke ohlelweni lokukhiqiza i-PCB, yiziphi izizathu zokugoba nokusonteka kwebhodi?
Isizathu sokugoba kwepuleti ngalinye nokugoba kwepuleti kungase kuhluke, kodwa konke kufanele kubalulwe ukucindezeleka okufakwe epuletini okukhulu kunokucindezeleka okungamelana nezinto zepuleti.Lapho ipuleti libhekene nokucindezeleka okungalingani noma Lapho ikhono lendawo ngayinye ebhodini lokumelana nokucindezeleka lingalingani, umphumela wokugoba ibhodi kanye ne-warping yebhodi izokwenzeka.Okulandelayo isifinyezo sezimbangela ezine ezinkulu zokugoba amapuleti kanye nokujika kwamapuleti.
1. Indawo yethusi engalingani ebhodini lesifunda iyokwenza kube kubi kakhulu ukugoba nokuwa kwebhodi
Ngokuvamile, indawo enkulu ye-foil yethusi iklanyelwe ebhodini lesifunda ngezinhloso zokubeka phansi.Ngezinye izikhathi indawo enkulu ye-foil yethusi nayo yakhelwe phezu kwe-Vcc layer.Lapho lezi zindwangu zethusi zendawo enkulu zingakwazi ukusatshalaliswa ngokulinganayo ebhodini lesifunda elifanayo Ngalesi sikhathi, kuzodala inkinga yokumunca ukushisa okungalingani kanye nokukhishwa kokushisa.Yiqiniso, ibhodi lesifunda nalo lizokhula futhi livumelane nokushisa.Uma ukunwetshwa nokufinyela kungeke kwenziwe ngesikhathi esifanayo, kuzodala ukucindezeleka nokuguqulwa okuhlukile.Ngalesi sikhathi, uma izinga lokushisa lebhodi selifinyelele ku-Tg Umkhawulo ophezulu wenani, ibhodi lizoqala ukuthambisa, libangele ukuguqulwa unomphela.
2. Isisindo sebhodi lesifunda ngokwalo sizobangela ukuthi ibhodi ligobe futhi liguqule
Ngokuvamile, isithando somlilo sokugeleza sisebenzisa iketanga ukushayela ibhodi lesifunda phambili esithandweni sokugeleza kabusha, okungukuthi, izinhlangothi ezimbili zebhodi zisetshenziswa njengama-fulcrums ukusekela lonke ibhodi.Uma kunezingxenye ezinzima ebhodini, noma ubukhulu bebhodi bukhulu kakhulu, Kuzobonisa ukucindezeleka phakathi ngenxa yenani lembewu, okwenza ipuleti ligobe.
3. Ukujula kwe-V-Cut kanye nomugqa wokuxhuma kuzothinta ukuguqulwa kwejigsaw
Ngokuyisisekelo, i-V-Cut iyicala elicekela phansi ukwakheka kwebhodi, ngoba i-V-Cut isika ama-grooves afana ne-V eshidini elikhulu lokuqala, ngakho-ke i-V-Cut ijwayele ukuguqulwa.
4. Amaphuzu okuxhumana (nge-vias) wesendlalelo ngasinye ebhodini lesifunda azokhawulela ukunwetshwa nokufinyela kwebhodi
Amabhodi esekethe anamuhla amabhodi amaningi anezingqimba eziningi, futhi kuzoba nezindawo zokuxhuma ezifana ne-rivet (nge) phakathi kwezendlalelo.Amaphuzu okuxhuma ahlukaniswe ngemigodi, imigodi eyimpumputhe kanye nemigodi egqitshiwe.Lapho kukhona izindawo zokuxhuma, ibhodi lizokhawulelwa.Umthelela wokunwetshwa nokufinyela uzophinda ubangele ngokungaqondile ukugoba kwepuleti nokujika kwepuleti.
Ngakho-ke singayivimbela kanjani kangcono inkinga yokungqubuzana kwebhodi ngesikhathi senqubo yokukhiqiza? Nazi izindlela ezimbalwa ezisebenzayo engithemba ukuthi zingakusiza.
1. Yehlisa umphumela wokushisa ekucindezelweni kwebhodi
Njengoba "izinga lokushisa" liwumthombo oyinhloko wokucindezeleka kwebhodi, inqobo nje uma izinga lokushisa lehhavini lokugeleza liyancipha noma izinga lokushisa kanye nokupholisa kwebhodi kuhhavini lokugeleza liyancipha, ukwenzeka kokugoba kwepuleti kanye ne-warpage kungaba kakhulu. kuncishisiwe.Kodwa-ke, eminye imiphumela emibi ingase yenzeke, njenge-solder short circuit.
2. Ukusebenzisa ishidi le-Tg eliphezulu
I-Tg izinga lokushisa lokushintsha kwengilazi, okungukuthi, izinga lokushisa lapho izinto ezibonakalayo zishintsha kusuka esimweni sengilazi kuya esimweni senjoloba.Lapho liphansi inani le-Tg lezinto ezibonakalayo, ibhodi liqala ukuthamba ngokushesha ngemva kokungena kuhhavini lokugeleza kabusha, futhi isikhathi esisithathayo ukuze sibe isimo senjoloba ethambile Lizoba lide, futhi ukuguqulwa kwebhodi kuzoba kubi kakhulu. .Ukusetshenziswa kweshidi le-Tg eliphakeme kungakhuphula ikhono lalo lokumelana nokucindezeleka nokuguqulwa, kodwa intengo yezinto ezihlobene nayo iphakeme.
3. Khulisa ubukhulu bebhodi lesifunda Ukuze kuzuzwe inhloso yokukhanya nokuzacisa emikhiqizweni eminingi ye-elekthronikhi, ukujiya kwebhodi kushiye u-1.0mm, 0.8mm, noma u-0.6mm.Ubukhulu obunjalo kufanele bugcine ibhodi lingaguquki ngemva kwesithando somlilo sokugeleza kabusha, okuyinto enzima ngempela.Kunconywa ukuthi uma kungekho mfuneko yokukhanya nokuqina, ubukhulu bebhodi kufanele bube ngu-1.6mm, okunganciphisa kakhulu ingozi yokugoba nokuguqulwa kwebhodi. 4. Yehlisa usayizi webhodi lesekhethi futhi unciphise inani lamaphazili Njengoba iningi lama-reflow furnaces lisebenzisa amaketanga ukuze liqhubele phambili ibhodi lesifunda, ubukhulu bebhodi lesifunda liyoba likhulu ngenxa yesisindo salo, ukubola kanye nokuguqulwa kwesithando somlilo, ngakho-ke zama ukubeka uhlangothi olude lwebhodi lesifunda. njengomphetho webhodi.Eketheni lesithando somlilo sokugeleza, ukucindezeleka nokuguqulwa okubangelwa isisindo sebhodi lesifunda kungancishiswa.Ukwehliswa kwenani lamaphaneli nakho kusekelwe kulesi sizathu.Okusho ukuthi, lapho udlula isithando somlilo, zama ukusebenzisa unqenqema oluncane ukuze udlule isiqondiso sesithando somlilo ngangokunokwenzeka.Inani le-deformation deformation. 5. I-tray yesithando somlilo esetshenzisiwe Uma izindlela ezingenhla zinzima ukufeza, okokugcina ukusebenzisa isithwali sokugeleza kabusha/isifanekiso ukuze kuncishiswe inani lokuguqulwa.Isizathu sokuthi kungani isithwali sokugeleza kabusha/isifanekiso singanciphisa ukugoba kwepuleti kungenxa yokuthi kuthenjwa ukuthi ukunwetshwa okushisayo noma ukufinyela okubandayo.Ithreyi ingabamba ibhodi lesifunda futhi ilinde kuze kube yilapho izinga lokushisa lebhodi lesifunda liphansi kunenani le-Tg bese liqala ukuqina futhi, futhi lingagcina nosayizi wangempela. Uma i-pallet yongqimba olulodwa ingakwazi ukunciphisa ukuguqulwa kwebhodi lesifunda, isembozo kufanele sengezwe ukuze ubambe ibhodi lesifunda ngamaphalethi aphezulu naphansi.Lokhu kunganciphisa kakhulu inkinga yokuguqulwa kwebhodi lesifunda ngokusebenzisa isithando somlilo sokugeleza kabusha.Nokho, leli threyi leziko libiza kakhulu, futhi umsebenzi wezandla uyadingeka ukuze ubeke futhi ugaywe kabusha amathreyi. 6. Sebenzisa i-Router esikhundleni se-V-Cut ukuze usebenzise i-sub-board Njengoba i-V-Cut izobhubhisa amandla esakhiwo sebhodi phakathi kwamabhodi wesifunda, zama ukungasebenzisi i-V-Cut sub-board noma ukunciphisa ukujula kwe-V-Cut.
7. Amaphuzu amathathu aqhubeka ekwakhiweni kobunjiniyela: A. Ukuhlelwa kwe-interlayer prepregs kufanele kulingane, isibonelo, kumabhodi anezingqimba eziyisithupha, ukujiya phakathi kwezingqimba ezi-1 ~ 2 kanye no-5~6 kanye nenani lama-prepregs kufanele kufane, ngaphandle kwalokho kulula ukujika ngemva kokulanyiswa. B. Multi-layer core board kanye prepreg kufanele kusebenzise imikhiqizo efanayo yomphakeli. C. Indawo yephethini yesifunda ohlangothini A no-B ohlangothini lwesendlalelo sangaphandle kufanele ibe seduze ngangokunokwenzeka.Uma uhlangothi lwe-A luyindawo enkulu yethusi, futhi uhlangothi luka-B lunemigqa embalwa kuphela, lolu hlobo lwebhodi eliphrintiwe lizosonteka kalula ngemva kokusijwa.Uma indawo yemigqa ezinhlangothini ezimbili ihluke kakhulu, ungakwazi ukwengeza amagridi azimele ohlangothini oluncane ukuze uthole ibhalansi. 8. I-latitude nobude be-prepreg: Ngemuva kokuthi i-prepreg i-laminated, amazinga e-warp kanye ne-weft shrinkage ahlukene, futhi izikhombisi-ndlela ze-warp kanye ne-weft kufanele zihlukaniswe ngesikhathi sokuvala kanye nokucwiliswa.Uma kungenjalo, kulula ukubangela ukuthi ibhodi eliqediwe liguqe ngemva kwe-lamination, futhi kunzima ukuyilungisa ngisho noma ingcindezi isetshenziswa ebhodini lokubhaka.Izizathu eziningi ze-warpage yebhodi le-multilayer ukuthi ama-prepregs awahlukanisiwe ku-warp ne-weft tinkhombandlela ngesikhathi sokugcoba, futhi apakishwe ngokungahleliwe. Indlela yokuhlukanisa izikhombisi-ndlela ze-warp kanye ne-weft: isiqondiso sokugoqa se-prepreg emgqeni isiqondiso se-warp, kanti isiqondiso sobubanzi siyindlela ye-weft;ebhodini le-foil yethusi, uhlangothi olude luyisiqondiso se-weft futhi uhlangothi olufushane luyisiqondiso se-warp.Uma ungaqiniseki, sicela uxhumane nomkhiqizi Noma umbuzo womphakeli. 9. Ibhodi lokubhaka ngaphambi kokusika: Inhloso yokubhaka ibhodi ngaphambi kokusika i-copper clad laminate (150 degrees Celsius, isikhathi esingamahora angu-8 ± 2) ukukhipha umswakama ebhodini, futhi ngesikhathi esifanayo wenze i-resin ebhodini iqine ngokuphelele, futhi uqhubeke nokuqeda umswakama ebhodini. ukucindezeleka okusele ebhodini, okuwusizo ekuvimbeleni ibhodi ukuthi lingaguquki.Kuyasiza.Njengamanje, amabhodi amaningi anezinhlangothi ezimbili kanye nezingqimba eziningi asabambelele esinyathelweni sokubhaka ngaphambi noma ngemva kokuvala.Nokho, kukhona okuhlukile kwezinye izimboni zamapuleti.Imithetho yamanje yesikhathi sokumisa ye-PCB yezimboni ezihlukahlukene ze-PCB nayo ayihambisani, kusukela emahoreni ama-4 kuye kwayi-10.Kunconywa ukunquma ngokuya ngebanga lebhodi eliphrintiwe elikhiqiziwe kanye nezidingo zekhasimende ze-warpage.Bhaka ngemuva kokusika i-jigsaw noma ukuvala ngemuva kokuthi ibhulokhi ibhakiwe lonke.Zombili izindlela zingenzeka.Kunconywa ukubhaka ibhodi ngemuva kokusika.Ibhodi lesendlalelo sangaphakathi kufanele libhakwe... 10. Ngaphezu kokucindezelwa ngemva kokulanywa: Ngemuva kokuthi ibhodi elinezingqimba eziningi licindezelwe ngokushisa futhi licindezelwe ngokubanda, liyakhishwa, lisikwe noma ligaywe ama-burrs, bese lifakwa phansi kuhhavini elingu-150 degrees Celsius amahora angu-4, ukuze ukucindezeleka ebhodini kufinyeleleke. kancane kancane ikhishwa futhi i-resin ilashwa ngokuphelele.Lesi sinyathelo asinakushiywa.
11. Ipuleti elincanyana lidinga ukuqondisa ngesikhathi se-electroplating: Uma ibhodi le-multilayer engu-0.4~0.6mm izacile kakhulu isetshenziselwa i-electroplating engaphezulu kanye ne-electroplating yephethini, ama-clamping roller akhethekile kufanele enziwe.Ngemva kokuba ipuleti elincanyana seliboshiwe ebhasini eliyimpukane emugqeni we-electroplating ozenzakalelayo, induku eyisiyingi isetshenziselwa ukubopha lonke ibhasi.Ama-roller ahlanganiswe ndawonye ukuze aqondise wonke amapuleti kuma-rollers ukuze amapuleti ngemva kokucwenga angeke akhubazeke.Ngaphandle kwalesi silinganiso, ngemva kokufaka i-electroplating ungqimba lwethusi lwama-microns angu-20 kuya kwangu-30, ishidi lizogoba futhi kunzima ukulilungisa. 12. Ukupholisa ibhodi ngemva kokulinganisa komoya oshisayo: Lapho ibhodi eliphrintiwe lilinganiswe nomoya oshisayo, lithintwa izinga lokushisa eliphezulu le-solder bath (cishe ama-250 degrees Celsius).Ngemva kokukhishwa, kufanele ibekwe phezu kwemabula eyisicaba noma ipuleti lensimbi ukuze iphole ngokwemvelo, bese ithunyelwa emshinini wokulungisa ngemva kokuhlanza.Lokhu kuhle ukuvimbela i-warpage yebhodi.Kwamanye amafekthri, ukuze kuthuthukiswe ukukhanya kwe-lead-tin surface, amabhodi afakwa emanzini abandayo ngokushesha ngemva kokuba umoya oshisayo ulinganisiwe, abese ekhishwa ngemva kwemizuzwana embalwa ukuze acutshungulwe.Lolu hlobo lomthelela oshisayo nobandayo lungabangela ukungqubuzana kwezinhlobo ezithile zamabhodi.Isontekile, inezingqimba noma inamabhamuza.Ngaphezu kwalokho, umbhede we-air flotation ungafakwa emishini yokupholisa. 13. Ukwelashwa kwebhodi elisontekile: Embonini ephethwe kahle, ibhodi eliphrintiwe lizohlolwa ukugcwala okungu-100% ngesikhathi sokuhlolwa kokugcina.Wonke amabhodi angafanelekile azokhethwa, afakwe kuhhavini, abhakwe ku-150 degrees Celsius ngaphansi kwengcindezi enzima amahora angu-3-6, futhi apholiswe ngokwemvelo ngaphansi kwengcindezi enkulu.Bese ukhulula ukucindezela kokukhipha ibhodi, futhi uhlole ukucaba, ukuze ingxenye yebhodi igcinwe, futhi amanye amabhodi adinga ukubhaka futhi acindezelwe kabili noma kathathu ngaphambi kokuba alinganiswe.Uma lezi zinyathelo ezishiwo ngenhla zokulwa ne-warping zingasetshenziswa, amanye amabhodi ayoba yize futhi angachithwa kuphela.
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