Maitiro ekudzivirira PCB tombstones kuremara mumusangano webhodhi redunhu

Munyaya yekubatanidza PCB , zvikanganiso zvakavhurika uye matombo eguva zvinowanzo sangana nematambudziko anogona kukanganisa mashandiro uye kuvimbika kwemidziyo yemagetsi. Kugadzira matongo, kunozivikanwawo seManhattan effect kana kuti Stonehenge effect, kunoitika kana mugumo mumwe wechikamu chekumusoro kwechinhu wakasungirirwa paPCB pad nepo mumwe mugumo usingabatanidzwi, zvichiita kuti chikamu chacho chimire chakamira sedombo reguva.

Yakavhurika kukanganisa, kune rumwe rutivi, inoreva kusakwana kana kuputsika kwemagetsi ekubatanidza, zvichikonzera maseketi akavhurika. Kugadzirisa zvikanganiso izvi kwakakosha kuti uve nechokwadi chekushanda kwakaringana kwePCB magungano. Mugwaro rino rakazara, tinoongorora zvikonzero uye matanho ekudzivirira kudzikamisa kuremara kwakavhurika uye matombo emakuva panguva yekusangana kwePCB.

ziviso

Iyo tombstone phenomenon, inozivikanwawo sePCB tombstone, inoonekwa panguva yewelding process yeMulti-layer Ceramic Capacitors (MLCCs) uye PCBs. Inoitika kana imwe mugumo weMLCC ichisiya nzvimbo yewelding uye inomira yakatwasuka kana yakarerekera. Nyaya iyi inonyanya kukonzerwa nekusagadzikana kwekunyorova kwesimba pamativi ese eMLCC panguva yewelding process. Zvikonzero zvikuru zvinokonzeresa kusimba kwesimba iri zvinosanganisira:

1. Asymmetric Heating: Migumo miviri yeMLCC haigoni kunyungudutswa panguva imwe chete, zvichiita kuti pave nekusawirirana kwepamusoro panguva yekunyunguduka.
2. Zvisina musoro Pad Dhizaini: Iyo pad dhizaini paPCB inogona kubatsira kune iyo tombstone chiitiko kana isina kugadzirwa nenzira kwayo kuti ive nechokwadi chekunyorova kwemativi ese eMLCC.

Kuti uderedze chiitiko cheguva, zvakakosha kuchengetedza nzvimbo yeMLCC yakachena uye kuterera kune padhi dhizaini paPCB. Izvi zvinosanganisira kuve nechokwadi chekuti solder paste basa harina kupera simba uye kuti MLCC inonyungudika zvakaenzana pamigumo miviri panguva yekugadzira. Nekushandisa matanho aya, chiitiko cheguva chinogona kudzivirirwa zvinobudirira, zvichitungamira kukuvandudzwa kwemhedzisiro yekugadzirwa uye kuderedzwa kwemitengo.

Kuongororwa kwechikonzero chePCB tombstone phenomenon

Iyo tombstone phenomenon, inozivikanwawo sePCB tombstone, inocherechedzwa panguva yekutengesa kweMLCCs uye PCBs, uye inogona kuverengerwa kune akati wandei zvikonzero zvinotungamira kune kusaenzana kunamatira solder. Kufamba kweMLCCs kunogona kuiswa mumhando nhatu huru:

Kuzvigadzirisa : Munguva yekuisa, musoro wekuisa wemuchina wekuisa unokurumidza kuisa MLCC pamapedhi ekuisa solder zvichibva pa X ne Y coordinates. Zvisinei, nekuda kwekusaenzana kwepedhi kana kutsvedza kwekuisa solder, MLCC inogona kukanganiswa ne angle (θ). Kana majoini ese ari maviri ekuisa solder anyunguduka panguva imwe chete, simba rekunyungudutsa tin rinodhonza MLCC kudzokera panzvimbo yayo chaiyo, ichigadzirisa kurongeka.

Kukwesha : Kana majoini maviri e solder asinganyungudike panguva imwe chete kana kana simba rekunyudza tin panzvimbo mbiri dzakasiyana zvakanyanya, rimwe rema solder pads rinogona kudhonza MLCC yakatwasuka, zvichiita kuti ikweshe.

Kutema Matombo : Izvi zvinoitika kana paine musiyano mukuru mumasimba ekunyudza matini kumativi ese eMLCC, kunyanya mumaMLCC madiki. Kusimba kwemusoro kunogona kukonzera kuti mugumo mumwe weMLCC udhonzwe kumusoro, zvichikonzera chiitiko chematombo eguva.

Michina yekuisa yemazuva ano inogona kutarisa nekugadzirisa zvese zviri zviviri X uye Y zvinorongedzerwa pamwe neiyo θ angle, kuderedza kuitika kwekuzvigadzirisa. Kuvandudzwa kwebhandi rekutakura kutsvedzerera kwakaderedzawo kutsauka pamberi pewelding. Nekudaro, kudzivirira skewing uye tombstoneing, zvakakosha kuve nechokwadi chekuti solder majoini anonyunguduka zvakafanana uye kuti kune yakaringana wetting simba pamativi ese eMLCC panguva yekushambadzira.

Matanho ekudzivirira Tombstones akaitika muPCB

Chiitiko cheguva muPCB musangano inyaya yakajairika iyo inogona kutungamira kune yakakosha mhando uye nyaya dzekuvimbika mumidziyo yemagetsi. Izvo zvinoitika kana imwe mugumo wepamusoro-yakaiswa chikamu, senge chip resistor kana capacitor, inosimudza kubva paPCB panguva yekuyerera solder process, yakafanana neguva. Dambudziko iri rinogona kukonzera kuvhurika kwemagetsi, kukanganisa kushanda kwedunhu uye zvinogona kutungamira kune inodhura rework kana chikamu chinotsiviwa.

Kudzivirira kuchekwa kwematombo paguva kunoda kunyatsotarisa zvinhu zvakasiyana-siyana, kusanganisira kushandiswa kwepaste yekusonesa, dhizaini yemapedhi, kuiswa kwezvikamu, uye parameters yekusonesa zvakare. Nekunzwisisa zvikonzero zvekushandiswa kwematombo paguva uye kushandisa matanho ekudzivirira, vagadziri vanogona kuvandudza goho uye kuvimbika kwema PCB avo. Kudzivirira kuchekwa kwematombo paguva paPCB, funga nezvenzira dzinotevera:

Stencil Design Optimization

Aperture Saizi uye Shape

Iyo stencil dhizaini inoita basa rakakosha mukudzivirira matombo emakuva panguva yekudhinda solder paste. Kugadzirisa saizi yeaperture uye chimiro kwakakosha kuti uve nechokwadi chekuisa yunifomu solder paste uye kuwana yakaenzana yekunyorova masimba pamativi ese echikamu. Bridged Aperture Entries (BAE) stencils anowanzo kufarirwa pamusoro pePeriphery Opened Ratio (POR) stencils, sezvo achiratidza kuita zvirinani mukudzikamisa kukanganiswa kwematombo eguva, kunyanya aine madiki echikamu uye mitsva yekugadzira paste.

Stencil Ukobvu

Ukobvu hwe stencil chimwe chinhu chakakosha chinokonzera solder paste kusunungurwa uye kuumbwa kweguva. A stencil ukobvu kubva 4 kusvika 8 iwe (0.1016 mm kusvika 0.2032 mm) inokurudzirwa kubata zvakakwana solder paste uye kufambisa yakavimbika kudhinda. Pamusoro pezvo, kukora kwe stencil kunofanirwa kugarisa zvimedu zvishanu zvekutengesa zvinotenderera nekaburi kadiki kuti ive nechokwadi chekufambisa paste.

Solder Mask Optimization

Solder Mask Ukobvu

Ukobvu hwemasiki emuchina wekusonesa hunoita basa rakakosha mukudzivirira oxidation uye matombo emuguva. Masiki emuchina wekusonesa akakora zvakanyanya anogona kutungamira pakuumbwa kwemabhii emuchina wekusonesa, zvichiwedzera njodzi yematombo emuguva. Saka, zvakakosha kuchengetedza ukobvu hwakakodzera hwemasiki emuchina wekusonesa kuti uwane kugona kwakakwana kwekusonesa.

Pad Design

Dhizaini yePCB pads inonyanya kukanganisa kuitika kwematombo emakuva. Kuve nechokwadi chekuti mapadhi anovhara anopfuura makumi mashanu muzana emateminari echikamu uye kuderedza nzvimbo pakati pemapadhi kunogona kuderedza mukana wekuumbwa kweguva panguva yekuyerera kwekutengesa.

Panyaya dzesarudzo dzekugadzira dzine chekuita neizvi, Highleap inonyorawo nezvekugadzirwa kwePCB uye kugadzirwa kwePCB , izvo zvinogona kubatsira kudzivirira zvikanganiso zvisina kujeka mupakeji yemutengo.

Component Placement uye Oriental

Balanced Thermal Conductivity

Kusaenzana kupisa conductivity mhiri PCB kunogona kubatsira tombstoneing. Kuti uderedze nyaya iyi, zvakakosha kuisa zvikamu zvakaenzana uye kuchengetedza maitiro akafanana uye kutsvaga upamhi. Iyi nzira inokurudzira kupisa kwakafanana panguva yekudzokazve, kuderedza njodzi yekusaenzana kwemasimba ekunyorova anotungamirira kumakuva.

Chikamu Sarudzo

Kusarudza zvidiki uye zvakareruka-huremu zvikamu zvinogona kubatsira kuderedza kuitika kwematombo emakuva. Zvikamu izvi hazvinyanyi kukanganiswa nekusagadzikana kwekunyorovesa masimba anokonzerwa neasina kuenzana solder paste kunyungudika kana kusiyanisa mukupisa conductivity.

Solder Paste Printing Process Optimization

Nama Ukobvu uye Uniformity

Kuve nechokwadi chekuenderana solder paste ukobvu uye kufanana mhiri kwePCB kwakakosha pakudzivirira matombo emakuva. Calibrating solder paste printing machines uye kuchengetedza kwakaringana ma parameter, senge squeegee pressure, kumhanya, uye kupatsanura, zvinogona kubatsira mukuwana yunifomu paste deposition.

Paste Formulation uye Rheology

Iko kuumbwa uye rheology ye solder paste inogona kukanganisa zvakanyanya maitiro ayo ekunyorova uye propensity ye tombstoneng. Kusarudza solder paste ine yakanaka solderability uye kunyorova maitiro, pamwe neakakodzera simbi mutoro uye viscosity, inogona kubatsira kuderedza kuumbwa kweguva.

Reflow Soldering Process Control

Thermal Profileing

Kushandisa yakanyatsodzorwa uye yakagadziridzwa yekupisa mbiri panguva yereflow soldering process kwakakosha kudzivirira makuva. Kudzika zvishoma nezvishoma uye yunifomu tembiricha yekukwira mhiri kwePCB inoderedza njodzi yekudziya kwenzvimbo uye kusaenzana kwekunyorovesa masimba ayo anogona kutungamira kune tombstone.

Preheat Stage

Kupisa kwakaringana kwePCB pamusoro kwakakosha kudzikisa mutsauko wakakura wetembiricha unogona kuguma mukuumbwa kwematani mabheji uye kunotevera matombo emakuva. Kuchengeta tembiricha yekupisa preheat mhiri kwePCB inova nechokwadi chekuti solder paste inonyungudika uye inoderedza njodzi yekusaenzana kwekunyorova kwemasimba.

Kuongorora uye Kudzora Kwemhando

In-Process Monitoring

Kuita-in-process yekutarisa uye yekuongorora maitiro kunogona kubatsira mukuona zvingangoitika zvinogona kutungamira kuvhurika hurema kana matombo emakuva. Chaiyo-nguva yekutarisisa kweiyo solder paste deposition, component placement, uye reflow profiles zvinogona kubatsira kuona uye kugadzirisa anomalies zvisati zvakonzera magungano akaremara.

Post-Assembly Inspection

Kuita kunyatsoongorora mushure memusangano kwakakosha kuona uye kugadzirisa chero hurema hwakavhurika kana matombo emakuva angave akaitika panguva yegungano. Kuongorora kwemaziso, otomatiki optical inspection (AOI), uye kuyedza magetsi zvinogona kushandiswa kuona nekugadzirisa zvinokanganisika kana zvinongedzo.

mhedziso

Kudzivirira kuremara kwakavhurika uye matombo emakuva panguva yekusangana kwePCB kunoda nzira ine mativi mazhinji inosanganisa akasiyana maitirwo ekugadzira. Nekugadzirisa stencil dhizaini, solder mask zvivakwa, chikamu chekuisa uye kusarudzwa, solder paste kudhinda, reflow soldering paramita, uye nekushandisa yakasimba yekuongorora uye matanho ekudzora emhando, vagadziri vanogona kuderedza zvakanyanya kuitika kwehurema uku uye kuvandudza kuvimbika kwese uye kushanda kwePCB yavo. maassemblies. Kuenderera mberi kwekutarisa, kuita optimization, uye kuomerera kumaindasitiri akanakisa maitiro ndiwo akakosha pakuwana emhando yepamusoro PCB magungano asina hurema hwakavhurika uye matombo emakuva.