SMT( Msonkhano wa Board Circuit Board , PCBA ) imatchedwanso luso lapamwamba lapamwamba.Panthawi yopangira, phala la solder limatenthedwa ndikusungunuka m'malo otentha, kotero kuti mapepala a PCB amaphatikizidwa modalirika ndi zigawo zokwera pamwamba pazitsulo zopangira phala.Izi timazitcha kuti reflow soldering.Ma board ambiri ozungulira amatha kupindika ndi kupindika pamene akudutsa Reflow (reflow soldering).Pazovuta kwambiri, zimatha kuyambitsa zinthu monga soldering yopanda kanthu ndi miyala yam'manda. Mu mzere wodziyimira pawokha, ngati PCB ya fakitale ya bolodi yozungulira si yathyathyathya, imayambitsa malo olakwika, zigawo sizingalowe m'mabowo ndi mapepala okwera pamwamba pa bolodi, ndipo ngakhale makina oyika okhawo adzawonongeka.The bolodi ndi zigawo zikuluzikulu amapindika pambuyo kuwotcherera, ndi chigawo mapazi ndi zovuta kudula bwino.Bolodi silingayikidwe pa chassis kapena socket mkati mwa makinawo, kotero ndizokwiyitsanso kwambiri kuti chomera cholumikizira chikakumana ndi bolodi.Pakali pano, matabwa osindikizidwa alowa m'nthawi ya kukwera pamwamba ndi kukwera kwa chip, ndipo zomera zosonkhana ziyenera kukhala ndi zofunikira zokhwima komanso zovuta kwambiri pamagulu othawirako.
Malinga ndi US IPC-6012 (kope la 1996) "Mafotokozedwe ndi Magwiridwe Antchito a Mabodi Osindikizidwa Okhazikika ", Pazipita zololeka warpage ndi kupotoza kwa pamwamba-wokwera kusindikizidwa matabwa ndi 0,75%, ndi 1.5% kwa matabwa ena. Poyerekeza ndi IPC-RB-276 (1992 edition), izi zasintha zofunikira za matabwa osindikizidwa pamwamba. pakalipano, tsamba lankhondo lomwe limaloledwa ndi zomera zosiyanasiyana zamagetsi, mosasamala kanthu za mbali ziwiri kapena zosanjikiza zambiri, makulidwe a 1.6mm, nthawi zambiri ndi 0.70 ~ 0.75%.
Kwa matabwa ambiri a SMT ndi BGA, chofunikira ndi 0.5%.Mafakitale ena apakompyuta akulimbikitsa kuti awonjezere kuchuluka kwa zida zankhondo mpaka 0.3%.Njira yoyesera warpage ikugwirizana ndi GB4677.5-84 kapena IPC-TM-650.2.4.22B.Ikani bolodi losindikizidwa pa nsanja yotsimikiziridwa, ikani pini yoyesera kumalo kumene digiri ya warpage ndi yaikulu kwambiri, ndikugawaniza kukula kwa pini yoyesera ndi kutalika kwa m'mphepete mwake mwa bolodi losindikizidwa kuti muwerenge tsamba la nkhondo. bolodi losindikizidwa.Kupindika kwapita.
Chifukwa chake popanga PCB, ndi zifukwa zotani za kupindika ndi kupindika kwa bolodi?
Zomwe zimapangitsa kuti mbale iliyonse ikhale yopindika komanso kupindika kwa mbale kungakhale kosiyana, koma zonsezi ziyenera kuganiziridwa ndi kupsinjika komwe kumagwiritsidwa ntchito pa mbale yomwe ili yaikulu kuposa kupsinjika komwe mbaleyo imatha kupirira.Pamene mbale ikukumana ndi kupsinjika kosagwirizana kapena Pamene kuthekera kwa malo aliwonse pa bolodi kukana kupsinjika kumakhala kosagwirizana, zotsatira za kupindika kwa bolodi ndi boarding warping zidzachitika.M'munsimu ndi chidule cha zifukwa zinayi zazikuluzikulu zopindika mbale ndi kupindika mbale.
1. Malo osagwirizana ndi mkuwa pa bolodi lozungulira adzawonjezera kupindika ndi kupindika kwa bolodi
Kawirikawiri, malo akuluakulu a zojambula zamkuwa amapangidwa pa bolodi la dera kuti apange maziko.Nthawi zina gawo lalikulu la zojambula zamkuwa limapangidwanso pa Vcc wosanjikiza.Pamene zojambula zamkuwa zazikuluzikuluzi sizingagawidwe mofanana pa bolodi la dera lomwelo Panthawiyi, zidzayambitsa vuto la kuyamwa kwa kutentha kosafanana ndi kutaya kutentha.Zoonadi, gulu la dera lidzakulitsanso ndikugwirizanitsa ndi kutentha.Ngati kukulitsa ndi kuphatikizika sikungachitike nthawi imodzi, kumayambitsa kupsinjika ndi kusinthika kosiyana.Panthawiyi, ngati kutentha kwa bolodi kwafika ku Tg Kumtunda kwa mtengo wamtengo wapatali, bolodi idzayamba kufewetsa, kuchititsa kusinthika kosatha.
2. Kulemera kwa bolodi lokhalokha kumapangitsa kuti bolodi likhale lopunduka ndi kupunduka
Kawirikawiri, ng'anjo ya reflow imagwiritsa ntchito unyolo kuyendetsa bolodi la dera kutsogolo mu ng'anjo yowonongeka, ndiko kuti, mbali ziwiri za bolodi zimagwiritsidwa ntchito ngati fulcrums kuthandizira bolodi lonse.Ngati pali mbali zolemetsa pa bolodi, kapena kukula kwa bolodi ndi lalikulu kwambiri, Zidzawonetsa kukhumudwa pakati chifukwa cha kuchuluka kwa mbewu, zomwe zimapangitsa kuti mbaleyo ikhale yopindika.
3. Kuya kwa V-Cut ndi chingwe cholumikizira chidzakhudza kusinthika kwa jigsaw.
Kwenikweni, V-Cut ndiye wolakwa yemwe amawononga kapangidwe ka bolodi, chifukwa V-Cut imadula ma grooves ooneka ngati V pa pepala lalikulu loyambirira, kotero kuti V-Cut imakonda kusinthika.
4. Mfundo zolumikizira (kudzera) za wosanjikiza uliwonse pa bolodi ladera zidzachepetsa kukulitsa ndi kutsika kwa bolodi
Ma board amasiku ano amakhala ambiri osanjikiza matabwa, ndipo padzakhala malo olumikizirana ngati ma rivet (kudzera) pakati pa zigawo.Mfundo zolumikizira zimagawidwa m'mabowo, mabowo akhungu ndi maenje okwiriridwa.Pomwe pali malo olumikizirana, bolodi idzaletsedwa.Zotsatira za kukulitsa ndi kutsika zidzachititsanso kuti mbale ikhale yopindika komanso kupindika kwa mbale.
Ndiye tingapewe bwanji vuto la board warping panthawi yopanga? Nazi njira zingapo zothandiza zomwe ndikuyembekeza zingakuthandizeni.
1. Kuchepetsa zotsatira za kutentha pazovuta za bolodi
Popeza "kutentha" ndiye gwero lalikulu la kupsinjika kwa bolodi, bola ngati kutentha kwa ng'anjo ya reflow kumatsitsidwa kapena kutsika kwa kutentha ndi kuzizira kwa bolodi mu uvuni wa reflow kumachepetsedwa, kupezeka kwa mbale yopindika ndi warpage kungakhale kwambiri. kuchepetsedwa.Komabe, zotsatira zina zimatha kuchitika, monga solder short circuit.
2. Kugwiritsa ntchito mapepala apamwamba a Tg
Tg ndi kutentha kwa magalasi, ndiko kuti, kutentha komwe zinthu zimasintha kuchokera ku galasi kupita ku mphira.Kutsika kwa mtengo wa Tg wa zinthuzo, bolodi imayamba kufewetsa mwachangu ikalowa mu uvuni wa reflow, ndipo nthawi yomwe imafunika kuti ikhale yofewa ya rabara Idzakhalanso yayitali, ndipo kusinthika kwa bolodi kudzakhala kokulirapo. .Kugwiritsa ntchito pepala lapamwamba la Tg kumatha kukulitsa kuthekera kwake kolimbana ndi kupsinjika ndi kusinthika, koma mtengo wazinthu zachibale umakhalanso wapamwamba.
3. Wonjezerani makulidwe a bolodi lozungulira Kuti akwaniritse cholinga chopepuka komanso chocheperako pazinthu zambiri zamagetsi, makulidwe a bolodi asiya 1.0mm, 0.8mm, kapena 0.6mm.Kuchuluka kotereku kuyenera kuteteza bolodi kuti lisawonongeke pambuyo pa ng'anjo ya reflow, zomwe zimakhala zovuta kwambiri.Ndibwino kuti ngati palibe chofunikira kuti chikhale chopepuka komanso chowonda, makulidwe a bolodi ayenera kukhala 1.6mm, zomwe zingachepetse kwambiri chiopsezo chopindika ndi kupunduka kwa bolodi. 4. Chepetsani kukula kwa bolodi lozungulira ndikuchepetsa kuchuluka kwa ma puzzles Popeza ambiri mwa ng'anjo reflow ntchito unyolo kuyendetsa bolodi dera patsogolo, lalikulu kukula kwa bolodi dera adzakhala chifukwa cha kulemera kwake, dent ndi mapindikidwe mu ng'anjo reflow, choncho yesetsani kuika mbali yaitali ya bolodi dera. monga m'mphepete mwa bolodi.Pa unyolo wa ng'anjo ya reflow, kukhumudwa ndi kusinthika komwe kumachitika chifukwa cha kulemera kwa bolodi ladera kumatha kuchepetsedwa.Kuchepetsa chiwerengero cha mapanelo kumachokeranso pazifukwa izi.Ndiko kunena kuti, podutsa ng'anjoyo, yesani kugwiritsa ntchito nsonga yopapatiza kuti mudutse njira ya ng'anjoyo momwe mungathere.Kuchuluka kwa deformation ya kukhumudwa. 5. Ntchito thireyi ya ng'anjo Ngati njira zomwe zili pamwambazi ndizovuta kukwaniritsa, chomaliza ndicho kugwiritsa ntchito reflow carrier / template kuti muchepetse kuchuluka kwa deformation.Chifukwa chomwe chonyamuliranso / template imatha kuchepetsa kupindika kwa mbale ndi chifukwa zimayembekezeredwa ngati kukulitsa kutentha kapena kuzizira kozizira.Sitimayi imatha kugwira bolodi lozungulira ndikudikirira mpaka kutentha kwa bolodi lozungulira kumakhala kotsika kuposa mtengo wa Tg ndikuyamba kuumanso, komanso kutha kukhalabe ndi kukula koyambirira. Ngati phasa limodzi-wosanjikiza silingathe kuchepetsa mapindikidwe a bolodi dera, chivundikirocho chiyenera kuwonjezeredwa kuti achepetse bolodi lozungulira ndi mapepala apamwamba ndi apansi.Izi zitha kuchepetsa kwambiri vuto la deformation board board kudzera mu ng'anjo ya reflow.Komabe, thireyi ya ng'anjoyi ndiyokwera mtengo kwambiri, ndipo pamafunika kugwira ntchito yamanja kuyika ndi kukonzanso thireyi. 6. Gwiritsani ntchito Router m'malo mwa V-Cut kuti mugwiritse ntchito bolodi yaying'ono Popeza V-Cut idzawononga mphamvu zamapangidwe a bolodi pakati pa matabwa ozungulira, yesetsani kuti musagwiritse ntchito V-Cut sub-board kapena kuchepetsa kuya kwa V-Cut.
7. Mfundo zitatu zikudutsa pakupanga mainjiniya: A. Makonzedwe a prepregs interlayer ayenera symmetrical, mwachitsanzo, kwa matabwa asanu wosanjikiza, makulidwe pakati pa 1 ~ 2 ndi 5 ~ 6 zigawo ndi chiwerengero cha prepregs ayenera kukhala chimodzimodzi, apo ayi n'zosavuta warps pambuyo lamination. B. Multi-layer core board ndi prepreg ayenera kugwiritsa ntchito zinthu zomwezo za supplier. C. Dera lachitsanzo cha dera kumbali A ndi mbali B ya wosanjikiza wakunja ayenera kukhala pafupi kwambiri.Ngati mbali ya A ndi yaikulu yamkuwa, ndipo mbali ya B ili ndi mizere yochepa chabe, bolodi lamtundu wotere likhoza kupindika mosavuta pambuyo polowa.Ngati dera la mizere kumbali ziwirizo ndi losiyana kwambiri, mukhoza kuwonjezera ma gridi odziimira pambali yopyapyala kuti muyese bwino. 8. Latitude ndi longitude ya prepreg: Pambuyo pa prepreg ndi laminated, mitengo ya warp ndi weft shrinkage imakhala yosiyana, ndipo njira za warp ndi weft ziyenera kusiyanitsa panthawi yobisala ndi kupukuta.Apo ayi, n'zosavuta kupangitsa bolodi lomalizidwa kuti ligwedezeke pambuyo pa kuyanika, ndipo n'zovuta kukonza ngakhale ngati kupanikizika kukugwiritsidwa ntchito pa bolodi lophika.Zifukwa zambiri warpage wa gulu multilayer ndi kuti prepregs si amasiyanitsidwa mu warp ndi weft malangizo pa lamination, ndipo zakhala zikuzunza m'miyoyo mwachisawawa. Njira yosiyanitsa njira za warp ndi weft: njira yopukutira ya prepreg mu mpukutu ndi njira yokhotakhota, pomwe m'lifupi ndi njira yokhotakhota;kwa bolodi lazojambula zamkuwa, mbali yayitali ndi njira ya weft ndipo mbali yaifupi ndi njira yozungulira.Ngati simukutsimikiza, chonde funsani kwa wopanga Kapena funso la ogulitsa. 9. Bolodi yophika musanadulire: Cholinga cha kuphika bolodi pamaso kudula mkuwa clad laminate (150 digiri Celsius, nthawi 8 ± 2 maola) ndi kuchotsa chinyezi mu bolodi, ndipo nthawi yomweyo kupanga utomoni mu bolodi kulimba kotheratu, ndi kuonjezera kuthetsa kupsinjika kotsalira mu bolodi, zomwe zimathandiza kupewa bolodi kuti lisagwedezeke.Kuthandiza.Pakalipano, matabwa ambiri amitundu iwiri komanso osanjikiza ambiri amatsatirabe sitepe yophika isanayambe kapena itatha.Komabe, pali kuchotserapo kwa mafakitale ena a mbale.Malamulo apano a PCB oyanika nthawi yamafakitole osiyanasiyana a PCB nawonso ndi osagwirizana, kuyambira maola 4 mpaka 10.Ndi bwino kusankha molingana ndi kalasi ya bolodi kusindikizidwa opangidwa ndi zofunika kasitomala kwa warpage.Kuphika mutatha kudula mu jigsaw kapena mutatseka chipika chonsecho.Njira zonsezi ndi zotheka.Ndi bwino kuphika bolodi pambuyo kudula.The internal layer board iyeneranso kuphikidwa ... 10. Kuphatikiza pa kupsinjika pambuyo pa lamination: Pambuyo pa bolodi lamitundu yambiri yotentha komanso kuzizira, imachotsedwa, kudula kapena kupukuta ma burrs, ndikuyika pansi mu uvuni pa madigiri 150 Celsius kwa maola 4, kuti kupsinjika mu bolodi kukhale pansi. amamasulidwa pang'onopang'ono ndipo utomoni umachiritsidwa kwathunthu.Sitingasiyidwe izi.
11. Mbale yopyapyala imayenera kuwongoleredwa panthawi ya electroplating: Pamene 0.4 ~ 0.6mm ultra-thin multilayer board agwiritsidwa ntchito pamwamba electroplating ndi chitsanzo electroplating, wapadera clamping rollers ayenera kupangidwa.Mbale yopyapyala ikakanikizidwa pa basi yowuluka pa mzere wa electroplating, ndodo yozungulira imagwiritsidwa ntchito kukakamiza basi yonse yakuwuluka.Odzigudubuza amamangiriridwa palimodzi kuti awongole mbale zonse pa zodzigudubuza kuti mbale pambuyo pa plating zisawonongeke.Popanda muyeso uwu, pambuyo pa electroplating mkuwa wosanjikiza wa 20 mpaka 30 ma microns, pepalalo lidzapindika ndipo kumakhala kovuta kuchikonza. 12. Kuziziritsa bolodi pambuyo poti mpweya wotentha usasunthike: Pamene bolodi losindikizidwa likuyendetsedwa ndi mpweya wotentha, limakhudzidwa ndi kutentha kwa madzi osambira (pafupifupi 250 digiri Celsius).Ikatulutsidwa, iyenera kuyikidwa pamiyala yathyathyathya kapena mbale yachitsulo kuti iziziziritsa mwachilengedwe, kenako imatumizidwa kumakina okonza pambuyo poyeretsa.Izi ndi zabwino kuti muteteze kuphulika kwa bolodi.M'mafakitale ena, kuti awonjezere kuwala kwa pamwamba pa malata otsogolera, matabwa amaikidwa m'madzi ozizira mwamsanga mpweya wotentha utatha, ndiyeno amachotsedwa pakapita masekondi angapo kuti akonze.Kutentha ndi kuzizira kotereku kungayambitse kumenyana pamitundu ina yamatabwa.Zopotoka, zosanjikiza kapena matuza.Kuphatikiza apo, bedi loyendetsa mpweya limatha kukhazikitsidwa pazida zoziziritsa. 13. Chithandizo cha bolodi lopindika: Pafakitale yoyendetsedwa bwino, bolodi losindikizidwa likhala 100% kupendekera koyang'aniridwa pakuwunika komaliza.Mabodi onse osayenerera adzasankhidwa, kuikidwa mu uvuni, kuphikidwa pa madigiri 150 Celsius pansi pa kupanikizika kwakukulu kwa maola 3-6, ndikuzizidwa mwachibadwa pansi pa kupanikizika kwakukulu.Kenaka chepetsani kupanikizika kuti mutenge bolodi, ndipo fufuzani kutsetsereka, kotero kuti gawo la bolodi likhoza kupulumutsidwa, ndipo matabwa ena amafunika kuphikidwa ndi kukanidwa kawiri kapena katatu asanasamuke.Ngati njira zotsutsana ndi nkhondo zomwe zatchulidwa pamwambapa sizikugwiritsidwa ntchito, matabwa ena adzakhala opanda ntchito ndipo akhoza kungochotsedwa.
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