SMT( INdibano yeBhodi yeSekethe eprintiweyo , PCBA ) ikwabizwa ngokuba yi-surface Mount technology.Ngexesha lenkqubo yokuvelisa, i-solder paste iyafudumala kwaye inyibilike kwindawo yokufudumala, ukwenzela ukuba iipadi ze-PCB zidibaniswe ngokuthembekileyo kunye nezixhobo zokunyuka komphezulu ngokusebenzisa i-solder paste alloy.Le nkqubo siyibiza ngokuba yireflow soldering.Uninzi lweebhodi zeesekethe ziqhelene nokugoba kwebhodi kunye ne-warping xa i-Reflow (reflow soldering).Kwiimeko ezinzima, kunokubangela amacandelo afana ne-solder engenanto kunye namatye engcwaba. Kwi-automated assembly line, ukuba i-PCB yefektri yebhodi yesiphaluka ayilulanga, iya kubangela ukumisa okungachanekanga, amacandelo awakwazi ukufakwa kwimingxuma kunye neepads zokunyuka kwendawo yebhodi, kwaye nokuba umatshini wokufaka ngokuzenzekelayo uya konakala.Ibhodi enamacandelo igobile emva kwe-welding, kwaye iinyawo zecandelo zinzima ukusika kakuhle.Ibhodi ayikwazi ukufakwa kwi-chassis okanye i-socket ngaphakathi kumatshini, ngoko ke kuyacaphukisa kakhulu ukuba isityalo sokuhlanganisana sidibane nebhodi yokulwa.Okwangoku, iibhodi eziprintiweyo ziye zangena kwixesha lokunyuka komphezulu kunye ne-chip mounting, kwaye izityalo zendibano kufuneka zibe neemfuneko ezingqongqo kunye nezingqongqo zokulwa nebhodi.
Ngokutsho kwe-US IPC-6012 (uHlelo luka-1996) "Inkcazo kunye neNgcaciso yokuSebenza ye Iibhodi eziprintiweyo eziqinileyo ", I-warpage ephezulu evumelekileyo kunye nokuphazamiseka kwiibhodi eziprintiweyo ezifakwe phezulu yi-0.75%, kunye ne-1.5% kwezinye iibhodi. ekhoyo, i-warpage evunyelwe yizityalo ezahlukeneyo ze-electronic assembly, kungakhathaliseki ukuba zimbini-macala okanye i-multi-layer, ubukhulu be-1.6mm, idla ngokuba yi-0.70 ~ 0.75%.
Kwiibhodi ezininzi ze-SMT kunye ne-BGA, imfuno yi-0.5%.Ezinye iifektri ze-elektroniki zikhuthaza ukunyusa umgangatho we-warpage ukuya kwi-0.3%.Indlela yokuvavanya i-warpage ihambelana ne-GB4677.5-84 okanye i-IPC-TM-650.2.4.22B.Beka ibhodi eprintiweyo kwiqonga eliqinisekisiweyo, faka isikhonkwane sovavanyo kwindawo apho iqondo le-warpage lilikhulu, kwaye ulwahlule ububanzi bephini lovavanyo ngobude bomphetho ogobileyo webhodi eprintiweyo ukubala i-warpage ye ibhodi eprintiweyo.Igophe limkile.
Ke kwinkqubo yokwenziwa kwePCB, zithini izizathu zokugoba kunye nokujika kwebhodi?
Isizathu sokugoba kwepleyiti nganye kunye ne-plate warping inokwahluka, kodwa yonke into kufuneka ifakwe kuxinzelelo olufakwe kwipleyiti enkulu kunoxinzelelo olunokuthi luxhathise izinto zepleyiti.Xa ipleyiti iphantsi koxinzelelo olungalinganiyo okanye Xa ukukwazi kwendawo nganye ebhodini ukuxhathisa uxinzelelo kungalingani, umphumo wokugoba kwebhodi kunye nebhodi yokulwa kuya kwenzeka.Oku kulandelayo sisishwankathelo sezizathu ezine eziphambili zokugotywa kwepleyiti kunye nokujika kweepleyiti.
1. Ummandla wobhedu ongalinganiyo kwibhodi yesekethe uya kubi nakakhulu ukugoba kunye ne-warping yebhodi
Ngokuqhelekileyo, indawo enkulu ye-foil yobhedu yenzelwe kwibhodi yesiphaluka ngenjongo yokumisa.Ngamanye amaxesha indawo enkulu ye-foil yobhedu nayo yenzelwe kwi-Vcc layer.Xa ezi zixhobo zobhedu zendawo enkulu azikwazi ukuhanjiswa ngokulinganayo kwibhodi yesekethe efanayo Ngeli xesha, kuya kubangela ingxaki yokutshatyalaliswa kobushushu obungalinganiyo kunye nokutshatyalaliswa kobushushu.Ngokuqinisekileyo, ibhodi yesekethe nayo iya kwandisa kwaye ivumelane nobushushu.Ukuba ukwandiswa kunye nokunciphisa akunakwenziwa ngexesha elifanayo, kuya kubangela uxinzelelo oluhlukeneyo kunye nokuguqulwa.Ngeli xesha, ukuba ukushisa kwebhodi kufikelele kwi-Tg Umda ophezulu wexabiso, ibhodi iya kuqala ukuthambisa, ibangele ukuguqulwa kwesigxina.
2. Ubunzima bebhodi yesekethe ngokwayo buya kubangela ukuba ibhodi idibanise kwaye iguqule
Ngokuqhelekileyo, i-furnace reflow isebenzisa ikhonkco ukuqhubela ibhodi yesiphaluka phambili kwisithando somlilo, oko kukuthi, amacala amabini ebhodi asetyenziswa njenge-fulcrums ukuxhasa ibhodi yonke.Ukuba kukho iindawo ezinzima ebhodini, okanye ubukhulu bebhodi bukhulu kakhulu, Kuya kubonisa ukudakumba phakathi ngenxa yobuninzi bembewu, ebangela ukuba ipleyiti igobe.
3. Ubunzulu be-V-Cut kunye nomgca wokudibanisa kuya kuchaphazela ukuguqulwa kwejigsaw.
Ngokwenene, i-V-Cut ngumtyholi otshabalalisa isakhiwo sebhodi, kuba i-V-Cut inqumla i-V-shaped grooves kwiphepha elikhulu lokuqala, ngoko i-V-Cut ixhomekeke kwi-deformation.
4. Amanqaku okudibanisa (i-vias) yoluhlu ngalunye kwibhodi yesekethe iya kunciphisa ukwanda kunye nokunciphisa ibhodi
Iibhodi zesekethe zanamhlanje zininzi iibhodi ezinomaleko amaninzi, kwaye kuya kubakho iindawo zonxibelelwano ezifana ne-rivet (nge) phakathi kweeleya.Amanqaku okudibanisa ahlulwe ngemingxuma, imingxuma eyimfama kunye nemingxuma engcwatywe.Apho kukho iindawo zokudibanisa, ibhodi iya kuthintelwa.Isiphumo sokwandiswa kunye nokucutheka kuya kubangela ukuba ipleyiti igobe kunye nokujika kwepleyiti.
Ke singayinqanda njani ngcono ingxaki yokulwa kwebhodi ngexesha lenkqubo yokuvelisa? Nazi iindlela ezimbalwa ezisebenzayo endithemba ukuba zingakunceda.
1. Ukunciphisa umphumo weqondo lokushisa kuxinzelelo lwebhodi
Ekubeni "ubushushu" ngowona mthombo uphambili woxinzelelo lwebhodi, okoko nje iqondo lobushushu le-oven yokubuyisela liyancipha okanye izinga lokufudumeza kunye nokupholisa kwebhodi kwi-oven yokubuyisela liyancipha, ukwenzeka kokugoba kwepleyiti kunye ne-warpage kunokuba kakhulu. kuncitshisiwe.Nangona kunjalo, ezinye iziphumo zecala zinokuthi zenzeke, njenge-solder short circuit.
2. Ukusebenzisa iphepha leTg eliphezulu
I-Tg yiqondo lokushisa lokutshintsha kweglasi, oko kukuthi, iqondo lokushisa apho izinto zitshintsha ukusuka kwiglasi ukuya kwimeko yerabha.Ixabiso eliphantsi le-Tg lezinto eziphathekayo, ngokukhawuleza ibhodi iqala ukuthamba emva kokungena kwi-oven yokubuyisela, kwaye ixesha elithathayo ukuba libe yimeko yerabha ethambileyo iya kuba yinde, kwaye ukuguqulwa kwebhodi kuya kuba nzima ngakumbi. .Ukusetyenziswa kwephepha leTg eliphezulu kunokunyusa amandla ayo okumelana noxinzelelo kunye nokuguqulwa, kodwa ixabiso lezinto ezihambelanayo nazo ziphezulu.
3. Ukwandisa ubukhulu bebhodi yesekethe Ukuze ufezekise injongo yokukhanya kunye nokuncinci kwiimveliso ezininzi ze-elektroniki, ubukhulu bebhodi bushiye i-1.0mm, 0.8mm, okanye i-0.6mm.Ubungqingqwa obunjalo kufuneka bugcine ibhodi ingakhuli emva kwesithando somlilo, okunzima ngokwenene.Kunconywa ukuba ukuba akukho mfuneko yokukhanya kunye nokunciphisa, ubukhulu bebhodi kufuneka bube yi-1.6mm, enokunciphisa kakhulu umngcipheko wokugoba kunye nokuguqulwa kwebhodi. 4. Ukunciphisa ubukhulu bebhodi yesekethe kwaye unciphise inani leepuzzle Ekubeni uninzi lweziko lokutshiza zisebenzisa amatyathanga ukuqhubela phambili ibhodi yesekethe, ubukhulu bebhodi yesekethe enkulu iya kuba ngenxa yobunzima bayo, i-dent kunye nokuguqulwa kwesithando somlilo, ngoko zama ukubeka icala elide lebhodi yesekethe. njengomphetho webhodi.Kwikhonkco lesithando somlilo, ukudakumba kunye nokuguqulwa okubangelwa ubunzima bebhodi yesiphaluka kunokunciphisa.Ukuncitshiswa kwenani leepaneli nako kusekelwe kwesi sizathu.Oko kukuthi, xa udlula isithando somlilo, zama ukusebenzisa i-edge emxinwa ukudlula ulwalathiso lwesithando somlilo kangangoko kunokwenzeka.Isixa sokudakumba deformation. 5. Ukusetyenziswa kwetreyi yesithando somlilo Ukuba iindlela ezingentla zinzima ukufezekisa, okokugqibela kukusebenzisa i-reflow carrier / template ukunciphisa inani le-deformation.Isizathu sokuba i-reflow carrier / template inokunciphisa ukugoba kwepleyiti kukuba kuthenjwa ukuba kukwandiswa kwe-thermal okanye ukucutha okubandayo.I-tray inokubamba ibhodi yesiphaluka kwaye ilinde de ukushisa kwebhodi yesiphaluka kuphantsi kwexabiso le-Tg kwaye iqale ukuqina kwakhona, kwaye inokugcina ubungakanani bokuqala. Ukuba i-pallet ye-single-layer ayikwazi ukunciphisa i-deformation yebhodi yesekethe, isigqubuthelo kufuneka songezwe ukuze sibambe ibhodi yesiphaluka kunye neepaliti eziphezulu kunye nezantsi.Oku kunokunciphisa kakhulu ingxaki yokuguqulwa kwebhodi yesiphaluka ngokusebenzisa isithando somlilo.Nangona kunjalo, le treyi yomlilo ibiza kakhulu, kwaye umsebenzi wezandla uyafuneka ukuze kubekwe kwaye kusetyenziswe ngokutsha iitreyi. 6. Sebenzisa i-Router endaweni ye-V-Cut ukusebenzisa i-sub-board Ekubeni i-V-Cut iya kutshabalalisa amandla okwakhiwa kwebhodi phakathi kweebhodi zeesekethe, zama ukungasebenzisi i-V-Cut sub-board okanye ukunciphisa ubunzulu be-V-Cut.
7. Amanqaku amathathu ahamba kuyilo lobunjineli: A. Ilungiselelo le-interlayer prepregs kufuneka lilingane, umzekelo, kwiibhodi ezinomaleko ezintandathu, ubukhulu phakathi kwe-1 ~ 2 kunye ne-5 ~ 6 umaleko kunye nenani le-prepregs kufuneka lifane, ngaphandle koko kulula ukujika emva kokuqhawula. B. Ibhodi engundoqo enemigangatho emininzi kunye ne-prepreg kufuneka isebenzise iimveliso zomboneleli ezifanayo. C. Ummandla wepatheni yesekethe kwicala A kunye necala B loluhlu lwangaphandle kufuneka lusondele ngokusemandleni.Ukuba icala elingu-A lingumphezulu wobhedu omkhulu, kwaye icala le-B linemigca embalwa kuphela, olu hlobo lwebhodi eprintiweyo luya kugoba ngokulula emva kokukrolwa.Ukuba indawo yemigca kumacala amabini ihluke kakhulu, unokongeza ezinye iigridi ezizimeleyo kwicala elincinci lokulinganisela. 8. Isibanzi kunye nobude be-prepreg: Emva kokuba i-prepreg i-laminated, i-warp kunye ne-weft shrinkage rates iyahluka, kwaye i-warp kunye ne-weft imiyalelo kufuneka yahlulwe ngexesha lokugubungela kunye ne-lamination.Ngaphandle koko, kulula ukubangela ukuba ibhodi egqityiweyo igqitywe emva kwe-lamination, kwaye kunzima ukuyilungisa nangona uxinzelelo lusetyenziswe kwibhodi yokubhaka.Izizathu ezininzi ze-warpage yebhodi ye-multilayer kukuba i-prepregs azahlulwanga kwi-warp kunye ne-weft imiyalelo ngexesha le-lamination, kwaye zipakishwe ngokungacwangciswanga. Indlela yokwahlula i-warp kunye ne-weft directions: i-rolling direction ye-prepreg kumqulu yi-warp direction, ngelixa ububanzi buyi-weft;kwibhodi yefoyile yobhedu, icala elide liyisalathiso se-weft kwaye icala elifutshane liyi-warp direction.Ukuba awuqinisekanga, nceda uqhagamshelane nomenzi okanye umbuzo womthengisi. 9. Ibhodi yokubhaka phambi kokusikwa: Injongo yokubhaka ibhodi ngaphambi kokusika i-laminate yobhedu (i-150 degrees Celsius, ixesha le-8±2 iiyure) kukususa ukufuma ebhodini, kwaye kwangaxeshanye yenza i-resin ebhodini iqine ngokupheleleyo, kwaye isuse ngakumbi uxinzelelo oluseleyo ebhodini, nto leyo eluncedo ukuthintela ibhodi ukusuka warping.Ukunceda.Okwangoku, iibhodi ezininzi ezinamacala amabini kunye neebhodi ezininzi zisabambelele kwisinyathelo sokubhaka ngaphambi okanye emva kokuvala.Nangona kunjalo, kukho izinto ezingaqhelekanga kwezinye iifektri zeeplate.Imimiselo yangoku yexesha lokumisa i-PCB yeefektri ezahlukeneyo ze-PCB nazo azihambelani, ukusuka kwi-4 ukuya kwiiyure ze-10.Kucetyiswa ukuba wenze isigqibo ngokwebakala lebhodi eprintiweyo eveliswe kunye neemfuno zomthengi ze-warpage.Bhaka emva kokusika kwijigsaw okanye ukuvala emva kokuba ibhloko yonke ibhakiwe.Zombini ezi ndlela zinokwenzeka.Kunconywa ukubhaka ibhodi emva kokusika.Ibhodi yomaleko wangaphakathi kufuneka nayo ibhakwe... 10. Ukongeza kuxinzelelo emva kwe-lamination: Emva kokuba ibhodi ye-multi-layer icinezele kwaye icinezele ngokubanda, ikhutshwe, inqunywe okanye ihlulwe kwi-burrs, kwaye emva koko ibekwe phantsi kwi-oven kwi-150 degrees Celsius ngeeyure ezi-4, ukwenzela ukuba uxinzelelo ebhodini ikhutshwe ngokuthe ngcembe kwaye i-resin iphiliswe ngokupheleleyo.Eli nyathelo alinakushiyeka.
11. Ipleyiti ebhityileyo kufuneka ilungiswe ngexesha le-electroplating: Xa i-0.4 ~ 0.6mm ibhodi ye-ultra-thin multilayer isetyenziselwa i-electroplating yomphezulu kunye ne-electroplating yepateni, i-clamping rollers ekhethekileyo kufuneka yenziwe.Emva kokuba ipleyiti ebhityileyo ibotshelelwe kwibhasi yempukane kumgca we-electroplating ozenzekelayo, intonga engqukuva isetyenziselwa ukucinezela yonke ibhasi yempukane.Ii-roller zixutywe kunye ukuze zilungelelanise zonke iiplate kwii-rollers ukwenzela ukuba iiplate emva kokubethelwa aziyi kuphazamiseka.Ngaphandle kwesi silinganisi, emva kwe-electroplating umaleko wobhedu wama-microns angama-20 ukuya kuma-30, iphepha liya kugoba kwaye kunzima ukulilungisa. 12. Ukupholisa ibhodi emva komgangatho womoya oshushu: Xa ibhodi eprintiweyo ilinganiswe ngumoya oshushu, ichaphazeleka ngubushushu obuphezulu bebhafu ye-solder (malunga nama-250 degrees Celsius).Emva kokuba ikhutshwe, kufuneka ifakwe kwi-marble flat okanye ipleyiti yensimbi yokupholisa kwendalo, emva koko ithunyelwe kumatshini wokucoca emva kokucoca.Oku kulungile ukuthintela warpage yebhodi.Kweminye imizi-mveliso, ukuze kwandiswe ukuqaqamba komphezulu wenkcenkce yelothe, iibhodi zifakwa kumanzi abandayo ngoko nangoko emva kokuba umoya oshushu ulinganisiwe, zize zikhutshwe emva kwemizuzwana embalwa ukuze zilungiswe.Olu hlobo lweempembelelo ezishushu nezibandayo zinokubangela ukungqubana kweentlobo ezithile zeebhodi.Ijijekile, ineleya okanye inamadyungudyungu.Ukongeza, ibhedi ye-air flotation inokufakwa kwisixhobo sokupholisa. 13. Unyango lwebhodi ephothiweyo: Kwifektri elawulwa kakuhle, ibhodi eprintiweyo iya kuhlolwa i-100% flatness ngexesha lokuhlolwa kokugqibela.Zonke iibhodi ezingafanelekanga ziya kuthathwa, zifakwe kwi-oven, zibhakwe kwi-150 degrees Celsius phantsi koxinzelelo olunzima kwiiyure ezingama-3-6, kwaye zipholile ngokwemvelo phantsi koxinzelelo olunzima.Emva koko ukhulule uxinzelelo lokukhupha ibhodi, kwaye uhlolisise ukucaca, ukuze inxalenye yebhodi igcinwe, kwaye ezinye iibhodi kufuneka zibhakwe kwaye zicinezelwe kabini okanye kathathu ngaphambi kokuba zilinganiswe.Ukuba amanyathelo enkqubo yokulwa ne-warping ekhankanywe ngasentla ayiphunyezwanga, ezinye iibhodi ziya kuba zingenamsebenzi kwaye zinokuchithwa kuphela.
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