Njira yophatikizira pamwamba pa phiri imagwiritsa ntchito ma templates ngati njira yolondola, yobwerezabwereza phala la solder. Template imatanthawuza pepala lopyapyala kapena lopyapyala lamkuwa kapena chitsulo chosapanga dzimbiri chokhala ndi mawonekedwe ozungulira odulidwa kuti agwirizane ndi mawonekedwe a chipangizo chokwera pamwamba (SMD) bolodi losindikizidwa (PCB) komwe template iyenera kugwiritsidwa ntchito. Pambuyo template ndi bwino pabwino ndi chikufanana ndi PCB, zitsulo squeegee kukakamiza solder phala kudutsa mabowo template, potero kupanga madipoziti pa PCB kukonza SMD m’malo. Ma depositi a solder amasungunuka akadutsa mu uvuni wa reflow ndikukonza SMD pa PCB.

Mapangidwe a template, makamaka mapangidwe ake ndi makulidwe ake, komanso mawonekedwe ndi kukula kwa mabowo, amatsimikizira kukula, mawonekedwe ndi malo a solder phala madipoziti, zomwe ndi zofunika kuonetsetsa mkulu-kudumpha msonkhano ndondomeko. Mwachitsanzo, makulidwe a zojambulazo ndi kukula kwa mabowo kumatanthawuza kuchuluka kwa slurry komwe kumayikidwa pa bolodi. Kuchuluka kwa solder phala kungayambitse mapangidwe a mipira, milatho ndi miyala ya tombstones. Kuchuluka kwa phala la solder kumapangitsa kuti ma solder aziuma. Zonsezi zidzawononga ntchito yamagetsi ya bolodi la dera.

Mulingo woyenera kwambiri zojambulazo makulidwe

Mtundu wa SMD pa bolodi umatanthawuza makulidwe oyenera a zojambulazo. Mwachitsanzo, kuyika zinthu monga 0603 kapena 0.020 ″ pitch SOIC kumafuna template yopyapyala ya solder, pomwe template yokhuthala ndiyoyenera kwambiri pazinthu monga 1206 kapena 0.050 ″ pitch SOIC. Ngakhale makulidwe a template yomwe amagwiritsidwa ntchito popanga solder paste imachokera ku 0.001 ″ mpaka 0.030 ″, makulidwe a zojambulazo omwe amagwiritsidwa ntchito pama board ambiri amayambira 0.004 ″ mpaka 0.007 ″.

Tekinoloje yopangira ma templates

Pakadali pano, makampaniwa amagwiritsa ntchito matekinoloje asanu kupanga ma stencil-laser kudula, electroforming, etching mankhwala ndi kusakaniza. Ngakhale ukadaulo wosakanizidwa ndi kuphatikiza kwa mankhwala etching ndi kudula laser, etching yamankhwala ndiyothandiza kwambiri popanga ma stencil ndi ma hybrid stencil.

Chemical etching of templates

Chemical mphero imayika chigoba chachitsulo ndi template yachitsulo yosinthika kuchokera mbali zonse. Popeza izi corrodes osati mu njira ofukula komanso lateral malangizo, izo zimayambitsa undercuts ndi kupanga kutsegula lalikulu kuposa kukula chofunika. Pamene etching ikupita kumbali zonse ziwiri, kugwedeza pakhoma lowongoka kumapangitsa kuti pakhale mawonekedwe a hourglass, zomwe zimabweretsa ma depositi owonjezera a solder.

Popeza kutseguka kwa stencil sikutulutsa zotsatira zosalala, makampaniwa amagwiritsa ntchito njira ziwiri kuti azisalaza makoma. Chimodzi mwa izo ndi electro-polishing ndi micro-etching process, ndipo chinacho ndi nickel plating.

Ngakhale kuti malo osalala kapena opukutidwa amathandizira kutulutsa phala, imathanso kupangitsa kuti phala lidumphe pamwamba pa template m’malo mogudubuza ndi chofinyira. Wopanga template amathetsa vutoli mwa kusankha kupukuta makoma a dzenje m’malo mwa template pamwamba. Ngakhale kuti nickel plating imatha kupangitsa kuti template ikhale yosalala komanso yosindikiza, imatha kuchepetsa kutseguka, komwe kumafuna kusintha kwazithunzi.

Template laser kudula

Kudula kwa laser ndi njira yochepetsera yomwe imalowetsa deta ya Gerber mu makina a CNC omwe amawongolera mtengo wa laser. Mtsinje wa laser umayamba mkati mwa malire a dzenje ndikudutsa malire ake ndikuchotsa zitsulo zonse kuti apange dzenje, dzenje limodzi lokha.

Magawo angapo amatanthauzira kusalala kwa laser kudula. Izi zikuphatikiza liwiro lodulira, kukula kwa malo amtengo, mphamvu ya laser ndi kuyang’ana kwa mtengo. Nthawi zambiri, makampaniwa amagwiritsa ntchito mtengo wa 1.25 mils, womwe umatha kudula mazenera olondola kwambiri pamawonekedwe ndi makulidwe osiyanasiyana. Komabe, mabowo odulidwa ndi laser amafunikiranso kukonzanso pambuyo pake, monga mabowo okhala ndi mankhwala. Makina odulira ma laser amafunikira kupukuta kwa electrolytic ndi nickel plating kuti khoma lamkati la dzenjelo likhale losalala. Monga kabowo kukula yafupika mu ndondomeko wotsatira, kukula kabowo wa laser kudula ayenera bwino kulipidwa.

Zotsatira za kugwiritsa ntchito stencil printing

Kusindikiza ndi stencil kumaphatikizapo njira zitatu zosiyana. Yoyamba ndi njira yodzaza dzenje, momwe solder phala imadzaza mabowo. Chachiwiri ndi solder phala kutengerapo ndondomeko, imene solder phala anasonkhanitsa mu dzenje anasamutsa kwa PCB pamwamba, ndi lachitatu ndi malo waikamo solder phala. Njira zitatuzi ndizofunikira kuti mupeze zotsatira zomwe mukufuna-kuyika voliyumu yeniyeni ya phala la solder (lotchedwanso njerwa) pamalo oyenera pa PCB.

Kudzaza mabowo a template ndi solder phala kumafuna scraper yachitsulo kuti akanikizire phala la solder m’mabowo. Mayendedwe a dzenje logwirizana ndi mzere wa squeegee amakhudza njira yodzaza. Mwachitsanzo, dzenje lokhala ndi olamulira atali olunjika pa kugunda kwa tsambalo limadzaza bwino kuposa dzenje lomwe lili ndi kanjira kakang’ono kolunjika kolowera ku stroke. Kuonjezera apo, popeza liwiro la squeegee limakhudza kudzazidwa kwa mabowo, kuthamanga kwapansi kungapangitse mabowo omwe kutalika kwake kumakhala kofanana ndi kugunda kwa squeegee bwino kudzaza mabowo.

Mphepete mwa mzere wa squeegee umakhudzanso momwe phala la solder limadzaza mabowo a stencil. Chizoloŵezi chachizolowezi ndi kusindikiza pamene mukugwiritsa ntchito kupanikizika kochepa kwa squeegee pamene mukusunga kupukuta koyera kwa phala la solder pamwamba pa stencil. Kuonjezera kupanikizika kwa squeegee kungawononge squeegee ndi template, komanso kumapangitsa kuti phala likhale lopaka pansi pa template.

Kumbali inayi, kupanikizika kwapansi kwa squeegee sikungalole kuti phala la solder litulutsidwe kudzera m’mabowo ang’onoang’ono, zomwe zimapangitsa kuti pakhale solder yosakwanira pa mapepala a PCB. Kuonjezera apo, phala la solder lomwe latsala pambali ya squeegee pafupi ndi dzenje lalikulu likhoza kugwedezeka ndi mphamvu yokoka, zomwe zimapangitsa kuti pakhale kuwonjezereka kwa solder. Choncho, kupanikizika kochepa kumafunika, zomwe zidzakwaniritsa kupukuta koyera kwa phala.

Kuchuluka kwa kukakamizidwa komwe kumagwiritsidwa ntchito kumadaliranso mtundu wa solder phala logwiritsidwa ntchito. Mwachitsanzo, poyerekeza ndi kugwiritsa ntchito malata / lead phala, pogwiritsa ntchito lead-free solder phala, PTFE/nickel-plated squeegee amafuna za 25-40% kukakamiza kwambiri.

Zochita za solder phala ndi stencil

Zina mwazochita zokhudzana ndi phala la solder ndi stencil ndi:

Makulidwe ndi kukula kwake kwa chojambula cha stencil kumatsimikizira kuchuluka kwa phala la solder lomwe layikidwa pa PCB pad.

Kutha kumasula phala la solder kuchokera pa khoma la template

Malo olondola a njerwa za solder zosindikizidwa pa PCB pads

Panthawi yosindikizira, pamene mzere wa squeegee umadutsa mu stencil, phala la solder limadzaza dzenje la stencil. Panthawi yolekanitsa bolodi / template, phala la solder lidzatulutsidwa pa mapepala pa bolodi. Momwemo, phala lonse la solder lomwe limadzaza dzenje panthawi yosindikizira liyenera kumasulidwa kuchokera pakhoma la dzenje ndikusamutsira ku pedi pa bolodi kuti apange njerwa yathunthu. Komabe, kusamutsidwa ndalama zimadalira mbali chiŵerengero ndi dera chiŵerengero cha kutsegula.

Mwachitsanzo, ngati dera la pad ndi lalikulu kuposa magawo awiri pa atatu aliwonse a khoma lamkati la pore, phala limatha kutulutsa bwino kuposa 80%. Izi zikutanthauza kuti kuchepetsa makulidwe a template kapena kuwonjezera kukula kwa dzenje kumatha kumasula phala la solder pansi pa chiŵerengero cha dera lomwelo.

Kuthekera kwa phala la solder kumasulidwa ku khoma la dzenje la template kumadaliranso kutha kwa khoma la dzenje. Mabowo odulira laser ndi electropolishing ndi/kapena electroplating amatha kupititsa patsogolo kusamutsa kwa slurry. Komabe, kutengerapo kwa solder phala kuchokera Chinsinsi kwa PCB komanso zimadalira pa adhesion wa solder phala kwa template dzenje khoma ndi adhesion wa solder phala kwa PCB PAD. Kuti mupeze zotsatira zabwino zosinthira, chotsiriziracho chiyenera kukhala chokulirapo, kutanthauza kuti kusindikizidwa kumadalira chiŵerengero cha khoma la template kumalo otsegulira, pamene kunyalanyaza zotsatira zazing’ono monga ndondomeko ya khoma ndi roughness yake. .

Malo ndi mawonekedwe olondola a njerwa za solder zosindikizidwa pa mapepala a PCB zimadalira mtundu wa deta yofalitsidwa ndi CAD, luso ndi njira zomwe zimagwiritsidwa ntchito popanga template, ndi kutentha kwa template panthawi yogwiritsira ntchito. Kuphatikiza apo, kulondola kwamalo kumadaliranso njira yolumikizira yomwe imagwiritsidwa ntchito.

template yokhazikika kapena glued template

The anamanga Chinsinsi panopa wamphamvu kwambiri laser kudula Chinsinsi, lakonzedwa kuti misa chophimba kusindikiza mu ndondomeko kupanga. Amayikidwa kwamuyaya mu chimango cha formwork, ndipo chimango cha mauna chimalimbitsa kwambiri zojambulazo mu formwork. Pakuti yaying’ono BGA ndi zigawo zikuluzikulu ndi phula la 16 mil ndi pansi, Ndi bwino kugwiritsa ntchito template yamatabwa ndi yosalala dzenje khoma. Akagwiritsidwa ntchito pansi pa kutentha kwa kutentha, nkhungu zopangidwira zimapereka malo abwino kwambiri komanso olondola.

Pakuti yochepa kupanga kapena chitsanzo PCB msonkhano, frameless zidindo angapereke bwino solder phala kulamulira buku. Amapangidwa kuti azigwiritsidwa ntchito ndi ma formwork tensioning system, omwe ndi mafelemu osinthika, monga mafelemu apadziko lonse lapansi. Popeza nkhungu sizimangiriridwa pa chimango, zimakhala zotsika mtengo kwambiri kuposa zoumba zamtundu wa chimango ndipo zimatenga malo ochepa kwambiri osungira.