SMT( Yakadhindwa Circuit Board Assembly , PCBA ) inodaidzwa zvakare kuti surface mount technology.Munguva yekugadzira, iyo solder paste inopisa uye yakanyungudutswa munzvimbo yekudziya, kuitira kuti maPCB pads asanganiswe zvakavimbika nepamusoro penzvimbo yekumusoro kuburikidza neiyo solder paste alloy.Isu tinodaidza iyi process reflow soldering.Mazhinji emabhodhi edunhu anowanzo pinda mubhodhi kukotama uye kuputika kana uchienda kuReflow (reflow soldering).Muzviitiko zvakakomba, zvinogona kutokonzera zvinhu zvakaita senge isina chinhu soldering uye tombstones. Mumutsara wekugadzira otomatiki, kana PCB yefekitori yedhipatimendi redunhu isina kufuratira, inokonzeresa kusamira zvakanaka, zvikamu hazvigone kuiswa mumakomba uye pamusoro pemapadhi ebhodhi, uye kunyange muchina wekuisa otomatiki uchakuvadzwa.Bhodhi rine zvikamu zvakakotama mushure mekuputika, uye chikamu chetsoka chakaoma kucheka zvakanaka.Iyo bhodhi haigone kuisirwa pane chassis kana socket mukati memuchina, saka zvakare zvinogumbura kuti dhizaini yegungano isangane nebhodhi warping.Parizvino, mabhodhi akadhindwa apinda munguva yekumisikidzwa kwepamusoro uye chip mounting, uye zvidyarwa zvemagungano zvinofanirwa kuve zvakaomarara uye zvakaomesesa zvinodiwa zvebhodhi warping.
Zvinoenderana neUS IPC-6012 (1996 Edition) "Specification uye Performance Specification ye Mabhodhi Akadhindwa Akaoma ", iyo yakanyanya kubvumidzwa warpage uye kukanganisa kwepamusoro-yakaiswa mabhodhi akadhindwa ndeye 0.75%, uye 1.5% kune mamwe mabhodhi. Zvichienzaniswa neIPC-RB-276 (edition ya1992), izvi zvakavandudza zvinodiwa zvemapuranga akadhindwa pamusoro. ikozvino, iyo warpage inobvumirwa nemagetsi akasiyana-siyana magungano emiti, zvisinei nemativi maviri-maviri kana akawanda-layer, 1.6mm ukobvu, kazhinji 0.70 ~ 0.75%.
Kune akawanda SMT uye BGA mabhodhi, chinodiwa 0.5%.Mamwe mafekitori emagetsi arikukurudzira kuwedzera mwero wewarpage kusvika 0.3%.Nzira yekuedza warpage inoenderana neGB4677.5-84 kana IPC-TM-650.2.4.22B.Isa bhodhi rakadhindwa papuratifomu yakasimbiswa, isa pini yebvunzo kunzvimbo iyo dhigirii rewarpage rakanyanya, uye patsanura dhayamita yepini yekuyedza nehurefu hwemucheto wakakomberedzwa webhodhi rakadhindwa kuti uverenge warpage ye bhodhi rakadhindwa.The curvature yaenda.
Saka mukugadzira PCB, ndezvipi zvikonzero zvekukotama uye kuputika kwebhodhi?
Chikonzero chekubhenda kwendiro yega yega uye kupeta kweplate kunogona kunge kwakasiyana, asi zvese zvinofanirwa kuverengerwa kushushikana kunoitwa mundiro iyo yakakura kupfuura kushushikana kunokwanisa kumira mundiro.Apo ndiro inoiswa pasi pekunetseka kusina kuenzana kana Kana kugona kwenzvimbo imwe neimwe pabhodhi kuramba kushushikana kusina kuenzana, mugumisiro wekukotama kwebhodhi uye bhodhi warping ichaitika.Inotevera ipfupiso yezvikuru zvina zvinokonzeresa kubhenda kweplate uye kuputika kweplate.
1. Nzvimbo yemhangura isina kuenzana pabhodhi redunhu ichawedzera kukotama uye kuputika kwebhodhi
Kazhinji, nzvimbo yakakura yemhangura yemhangura inogadzirwa pabhodhi redunhu nekuda kwekugadzirisa.Dzimwe nguva nzvimbo yakakura yemhangura foil yakagadzirwawo paVcc layer.Apo idzi nzvimbo huru dzemhangura mapepa asingagoni kugoverwa zvakaenzana pabhodhi redunhu rimwechete Panguva ino, inokonzera dambudziko rekupisa kusina kuenzana nekupisa kupisa.Zvechokwadi, bhodhi redunhu richawedzerawo uye chibvumirano nekupisa.Kana kuwedzera uye kuputika kusingagoni kuitwa panguva imwe chete, kunokonzera kushushikana kwakasiyana uye deformation.Panguva ino, kana kutonhora kwebhodhi kwasvika Tg Muganhu wepamusoro wekukosha, bhodhi inotanga kupfava, zvichiita kuti deformation isingaperi.
2. Huremu hwebhodhi redunhu pachahwo huchaita kuti bhodhi rive rakaputika uye rinokanganisa
Kazhinji, choto che reflow chinoshandisa cheni kutyaira bhodhi redunhu mberi muvira rekuyerera, kureva kuti, mativi maviri ebhodhi anoshandiswa se fulcrums kutsigira bhodhi rose.Kana pane zvikamu zvinorema pabhodhi, kana hukuru hwebhodhi hwakanyanya kukura, Icharatidza kuora mwoyo kwepakati nekuda kwehuwandu hwembeu, zvichiita kuti ndiro ikotame.
3. Kudzika kweV-Cheka uye tambo yekubatanidza ichakanganisa deformation yejigsaw.
Chaizvoizvo, V-Cheka ndiye ane mhosva inoparadza chimiro chebhodhi, nekuti V-Cheka inocheka V-yakaita grooves pane yepakutanga pepa guru, saka iyo V-Cut inowanzoita deformation.
4. Iwo mapoinzi ekubatanidza (vias) ega ega dhizaini pabhodhi redunhu anozoganhura kuwedzera uye kuderera kwebhodhi
Mabhodhi edunhu anhasi anonyanya kuwanda-mabhodhi, uye pachave nerivet-senge mapoinzi ekubatanidza (kuburikidza) pakati pematanho.Iwo mapoinzi ekubatanidza akakamurwa kuva kuburikidza nemakomba, maburi mapofu uye makomba akavigwa.Apo pane nzvimbo dzekubatanidza, bhodhi richarambidzwa.Mhedzisiro yekuwedzera uye kudonhedza ichaitawo zvisina kunanga kubhenda kweplate uye kuputika kweplate.
Saka isu tingadzivise sei zvirinani dambudziko rebhodhi warping panguva yekugadzira? Heano maitiro mashoma anoshanda ayo ndinovimba anogona kukubatsira.
1. Deredza mhedzisiro yekushisa pane kushushikana kwebhodhi
Sezvo "tembiricha" iriyo inonyanya kukonzera kushushikana kwebhodhi, chero bedzi tembiricha yehovhoni inoyerera ichidzikiswa kana mwero wekupisa uye kutonhora kwebhodhi muovheni reflow inononoka, kuitika kwekukotama kweplate uye warpage kunogona kuve kwakanyanya. kuderedzwa.Zvisinei, mamwe migumisiro inogona kuitika, yakadai solder short circuit.
2. Kushandisa high Tg sheet
Tg ndiyo tembiricha yekuchinja kwegirazi, ndiko kuti, tembiricha painochinja zvinhu kubva pagirazi kuenda kune rabha.Iyo yakaderera kukosha kweTg yezvinhu, nekukurumidza bhodhi rinotanga kupfava mushure mekupinda muovheni yekuyerera, uye nguva yainotora kuti ive yakapfava rubber mamiriro Inozove zvakare kureba, uye deformation yebhodhi ichave yakakomba zvakanyanya. .Iko kushandiswa kwepamusoro Tg pepa kunogona kuwedzera kugona kwayo kutsungirira kushushikana uye deformation, asi mutengo wezvinhu zvakabatana wakakwira zvakare.
3. Wedzera kukora kwebhodhi redunhu Kuti uwane chinangwa chekureruka uye kutetepa kune zvakawanda zvigadzirwa zvemagetsi, ukobvu hwebhodhi hwakasiya 1.0mm, 0.8mm, kana kunyange 0.6mm.Ukobvu hwakadaro hunofanira kuchengetedza bhodhi kubva pakukanganisa mushure memoto wekuyerera, izvo zvakaoma chaizvo.Zvinokurudzirwa kuti kana pasina chinodikanwa chekureruka uye kuonda, ukobvu hwebhodhi hunofanirwa kunge huri 1.6mm, izvo zvinogona kuderedza zvakanyanya njodzi yekukotama uye deformation yebhodhi. 4. Deredza ukuru hwebhodhi redunhu uye kuderedza nhamba yepuzzles Sezvo mazhinji emafuta ekudzoreredza anoshandisa maketani kutyaira bhodhi redunhu kumberi, iyo yakakura saizi yedare redunhu ichave nekuda kwehuremu hwayo, dent uye deformation muchoto chekuyerera, saka edza kuisa iyo refu divi redunhu bhodhi. somupendero wepuranga.Pamusoro peketani yevira reflow, kuora mwoyo uye deformation inokonzerwa nekurema kwebhodhi redunhu inogona kuderedzwa.Kuderedzwa kwenhamba yemapanera kunobvawo pachikonzero ichi.Izvi zvinoreva kuti, kana uchipfuura choto, edza kushandisa mupendero wakamanikana kuti upfuure kutungamira kwechoto kusvika pazvinobvira.Kuwanda kwekuora mwoyo deformation. 5. Yakashandiswa tireyi yevira remoto Kana nzira dziri pamusoro dzakaoma kuwana, yekupedzisira ndeye kushandisa reflow carrier / template kuderedza kuwanda kwe deformation.Chikonzero nei reflow carrier/template ichigona kuderedza kukotama kweplate imhaka yekuti inotarisirwa kungave kuwedzera kwemafuta kana kutonhora kwechando.Iyo tireyi inogona kubata bhodhi redunhu uye kumirira kusvikira tembiricha yedunhu bhodhi yakaderera pane Tg kukosha uye kutanga kuomesa zvakare, uye inogona zvakare kuchengetedza saizi yepakutanga. Kana iyo imwe-layer pallet isingakwanise kuderedza deformation yedare redunhu, chivharo chinofanira kuwedzerwa kuti chisungirire bhodhi redunhu nepamusoro uye pasi pallets.Izvi zvinogona kuderedza zvakanyanya dambudziko rekutenderera bhodhi deformation kuburikidza nereflow furnace.Nekudaro, tireyi yechoto iyi inodhura zvakanyanya, uye basa remaoko rinodiwa kuisa nekudzokorodza matireyi. 6. Shandisa Router panzvimbo yeV-Cheka kushandisa sub-board Sezvo V-Cut ichaparadza simba rekugadzirisa bhodhi pakati pemapuranga edunhu, edza kusashandisa V-Cut sub-board kana kuderedza kudzika kweV-Cut.
7. Mapoinzi matatu anomhanya mukugadzira engineering: A. Kurongeka kwe interlayer prepregs kunofanira kuenzana, semuenzaniso, kune matanhatu-layer mapuranga, ukobvu pakati pe1 ~ 2 uye 5 ~ 6 akaturikidzana uye nhamba ye prepregs inofanira kunge yakafanana, zvikasadaro zviri nyore kuchinjika mushure melamination. B. Multi-layer core board uye prepreg inofanira kushandisa zvakafanana zvigadzirwa zvemupi. C. Nharaunda yemuenzaniso wedunhu padivi A nedivi B rekunze rekunze rinofanira kunge riri pedyo sezvinobvira.Kana iyo A side inzvimbo hombe yemhangura, uye B side riine mitsetse mishoma, rudzi urwu rwebhodhi rakadhindwa rinongopeta nyore mushure mekucheka.Kana nzvimbo yemitsara pamativi maviri akasiyana zvakanyanya, unogona kuwedzera mamwe magiradhi akazvimirira padivi rakatetepa rekuenzanisa. 8. Latitude uye longitude ye prepreg: Mushure mekunge prepreg yaiswa laminated, iyo warp uye weft shrinkage mazinga akasiyana, uye iyo warp uye weft nzira dzinofanirwa kusiyaniswa panguva yekuvharika uye nekukasira.Kana zvisina kudaro, zviri nyore kuita kuti bhodhi rakapedzwa rive rakaputika mushure mekucheka, uye zvakaoma kuzvigadzirisa kunyange kana kumanikidzika kuchiiswa pabhodhi rekubheka.Zvikonzero zvakawanda zvewarpage yebhodhi remultilayer ndezvekuti prepregs haina kusiyaniswa muwarp uye weft nzira panguva yekumisikidza, uye akaturikidzana zvisina tsarukano. Nzira yekusiyanisa nzira yewap uye weft: nzira yekutenderera ye prepreg mumupumburu ndiyo nzira yewap, ukuwo hupamhi inzira yeweft;kune bhodhi refoil yemhangura, rutivi rwakareba inzira yeweft uye rutivi rupfupi inzira yewap.Kana iwe usina chokwadi, ndapota taura nemugadziri Kana mupi mubvunzo. 9. Baking board usati wacheka: Chinangwa chekubika bhodhi usati wacheka copper clad laminate (150 degrees Celsius, nguva 8±2 maawa) kubvisa hunyoro mubhodhi, uye panguva imwechete kuita kuti resin iri mubhodhi inyatsosimba, uyezve kubvisa kusara kunetseka mubhodhi, iyo inobatsira kudzivirira bhodhi kubva kuhondo.Kubatsira.Parizvino, akawanda maviri-mativi uye akawanda-layer mabhodhi achiri kuomerera kune nhanho yekubheka pamberi kana mushure mekuvharika.Nekudaro, kune zvisizvo kune mamwe mafekitori eplate.Iyo yazvino PCB yekuomesa nguva mirau yeakasiyana mafekitori ePCB zvakare haawirirane, kubva pa4 kusvika kumaawa gumi.Zvinokurudzirwa kusarudza zvinoenderana negiredhi rebhodhi rakadhindwa rakagadzirwa uye zvinodiwa nemutengi zvewarpage.Bika mushure mekucheka mujigsaw kana kuvhara mushure mekunge chivharo chose chabikwa.Nzira mbiri idzi dzinogoneka.Inokurudzirwa kubika bhodhi mushure mekucheka.Iyo yemukati layer board inofanirawo kubikwa... 10. Mukuwedzera kune kushushikana mushure mekucheka: Mushure mekunge bhodhi re-multi-layer bhodhi richipisa-kudzvanywa uye kutonhora-kudzvanywa, rinotorwa, rakatemwa kana kunyungudutswa kubva pamaburrs, uye rozoiswa muchoto pa150 degrees Celsius kwemaawa mana, kuitira kuti kushushikana mubhodhi kuve. zvishoma nezvishoma inosunungurwa uye resin inorapwa zvachose.Danho iri harigoni kusiiwa.
11. Iyo ndiro yakatetepa inoda kutwasanudzwa panguva ye electroplating: Kana iyo 0.4 ~ 0.6mm yekupedzisira-yakaonda multilayer board ichishandiswa pamusoro pe electroplating uye pateni electroplating, yakakosha clamping rollers inofanirwa kugadzirwa.Mushure mekunge ndiro yakatetepa yasungirirwa pabhazi renhunzi pamutsetse weotomatiki wemagetsi, tsvimbo yeraundi inoshandiswa kusunga bhazi rose rinobhururuka.Mapumburu anosungirirwa pamwe chete kuti atwasanudze mahwendefa ese ari pamipumburu kuitira kuti mahwendefa mushure mekuputira arege kukanganiswa.Pasina chiyero ichi, mushure me electroplating mhangura yemhangura ye 20 kusvika ku30 microns, pepa richakotama uye zvakaoma kuzvigadzirisa. 12. Kutonhodzwa kwebhodhi mushure mekugadzirisa mhepo inopisa: Kana iyo bhodhi yakadhindwa yakaenzaniswa nemhepo inopisa, inobatwa nekupisa kwepamusoro kwebhati ye solder (inenge 250 degrees Celsius).Mushure mekubudiswa kunze, inofanira kuiswa pamarble flat kana ndiro yesimbi yekutonhodza kwechisikigo, uye yozotumirwa kumuchina wepashure wekuchenesa.Izvi zvakanaka kudzivirira warpage yebhodhi.Mune mamwe mafekitori, kuitira kuti kuwedzere kupenya kwelead-tin pamusoro, mapuranga anoiswa mumvura inotonhora pakarepo mushure mekunge mhepo inopisa yaiswa, uye yozotorwa kunze mushure memasekondi mashoma ekugadziriswa.Rudzi urwu rwekupisa uye kutonhora kunokanganisa kunogona kukonzera kutenderera kune mamwe marudzi emabhodhi.Yakamonyoroka, yakaturikidzana kana mabhunu.Mukuwedzera, mubhedha wemhepo inotenderera inogona kuiswa pamidziyo yekutonhodza. 13. Kurapwa kwewarped board: Mufekitari inotungamirirwa zvakanaka, bhodhi rakadhindwa richave 100% flatness yakaongororwa panguva yekupedzisira kuongorora.Mabhodhi ese asina kukodzera anosarudzwa, oiswa muchoto, obikwa pa150 degrees Celsius pasi pekumanikidzwa kukuru kwemaawa 3-6, uye akatonhodzwa zvechisikigo pasi pekumanikidzwa kukuru.Zvadaro bvisa dzvinyiriro yekubvisa bhodhi, uye tarisa flatness, kuitira kuti chikamu chebhodhi chigone kuponeswa, uye mamwe mapuranga anofanira kubikwa uye kudzvinyirirwa kaviri kana katatu asati akwanisa kuenzaniswa.Kana matanho akataurwa pamusoro apa ekurwisa-warping akasaitwa, mamwe mabhodhi achange asingabatsiri uye anogona kungoraswa.
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