Mayelana nokuhlelwa kwe-PCB nenkinga yezintambo, namuhla ngeke sikhulume ngokuhlaziywa kobuqotho besignali (SI), ukuhlaziywa kokuhambisana kwe-electromagnetic (EMC), ukuhlaziywa kobuqotho bamandla (PI).Ukukhuluma nje ngokuhlaziywa kokwenziwayo (DFM), ukwakheka okungenangqondo kokwenziwa nakho kuzoholela ekuhlulekeni komklamo womkhiqizo.
I-DFM ephumelelayo esakhiweni se-PCB iqala ngokusetha imithetho yedizayini ukuze ibhekane nezingqinamba ezibalulekile ze-DFM.Imithetho ye-DFM eboniswe ngezansi ibonisa amanye amakhono edizayini wesimanje abakhiqizi abaningi abangawathola.Qinisekisa ukuthi imikhawulo ebekwe emithethweni yokuklama ye-PCB ayiphuli ukuze kuqinisekiswe imikhawulo eminingi yedizayini evamile.
Inkinga ye-DFM yomzila we-PCB incike ekuhlelweni okuhle kwe-PCB, futhi nemithetho yomzila ingase isethwe kusengaphambili, okuhlanganisa nenani lezikhathi zokugoba zolayini, inani lezimbobo zokuqhuba, inani lezinyathelo, njll. Ngokuvamile, izintambo zokuhlola ziyathwalwa. ukuphuma kuqala ukuxhuma imigqa emifushane ngokushesha, bese kwenziwa i-labyrinth wiring.Ukwenziwa ngcono kwendlela yomzila yomhlaba wonke kwenziwa ezintanjeni ezizobekwa kuqala, futhi ukuphinda kufakwe izintambo kuzanywa ukuthuthukisa umthelela ophelele kanye nokwenziwa kwe-DFM.
1.SMT amadivayisi
Isikhala sesakhiwo sedivayisi sihlangabezana nezidingo zokuhlanganisa, futhi ngokuvamile sikhulu kuno-20mil kumadivayisi afakwe phezulu, ama-80mil kumadivayisi e-IC, kanye no-200mi kumadivayisi e-BGA.Ukuze kuthuthukiswe ikhwalithi kanye nesivuno senqubo yokukhiqiza, isikhala sedivayisi singahlangabezana nezidingo zokuhlanganisa.
Ngokuvamile, ibanga eliphakathi kwamaphedi e-SMD wezikhonkwane zedivayisi kufanele libe likhulu kuno-6mil, futhi amandla okwenziwa kwebhuloho elidayiswayo ngu-4mil.Uma ibanga eliphakathi kwamapayipi e-SMD lingaphansi kwe-6mil futhi ibanga phakathi kwefasitela le-solder lingaphansi kwe-4mil, ibhuloho le-solder alikwazi ukugcinwa, okuholela ezingxenyeni ezinkulu ze-solder (ikakhulukazi phakathi kwezikhonkwane) ohlelweni lomhlangano, oluzoholela kumjikelezo omfushane.
2.DIP idivayisi
Kufanele kucatshangelwe ukuhlukaniswa kwamaphini, isiqondiso kanye nesikhala semishini enqubweni ye-over wave soldering.Isikhala sephinikhodi esinganele sedivayisi sizoholela ethanini le-soldering, okuzoholela ekujikelezeni okufushane.
Abaklami abaningi banciphisa ukusetshenziswa kwamadivayisi akulayini (THTS) noma bawabeke ohlangothini olulodwa lwebhodi.Kodwa-ke, amadivayisi akulayini ngokuvamile awagwemeki.Endabeni yokuhlanganiswa, uma idivayisi ye-in-line ibekwe phezu kwesendlalelo esiphezulu futhi idivayisi yokunamathisela ibekwe phansi, kwezinye izimo, izoba nomthelela ekuhlanganisweni kwamagagasi ohlangothi olulodwa.Kulokhu, izinqubo zokushisela ezibiza kakhulu, njenge-welding ekhethiwe, zisetshenziswa.
3.ibanga phakathi kwezingxenye kanye nonqenqema lwepuleti
Uma umshini wokushisela, ibanga eliphakathi kwezingxenye ze-elekthronikhi kanye nonqenqema lwebhodi ngokuvamile liyi-7mm (abakhiqizi abahlukene be-welding banezidingo ezahlukene), kodwa futhi lingangezwa emphethweni wenqubo yokukhiqiza ye-PCB, ukuze izingxenye ze-electronic zibe ibekwe onqenqemeni lwebhodi le-PCB, inqobo nje uma ilungele izintambo.
Kodwa-ke, lapho unqenqema lwepuleti lushiselwe, lungase luhlangane nomzila wesitimela womshini futhi kulimaze izingxenye.Iphedi yedivayisi emaphethelweni epuleti izokhishwa kunqubo yokukhiqiza.Uma i-pad incane, ikhwalithi ye-welding izothinteka.
I-4.Ibanga lamadivayisi aphezulu / aphansi
Kunezinhlobo eziningi zezingxenye ze-elekthronikhi, izimo ezihlukene, nemigqa ehlukahlukene yomthofu, ngakho-ke kunomehluko endleleni yokuhlanganisa yamabhodi aphrintiwe.Ukuhlelwa okuhle akukwazi nje ukwenza ukusebenza komshini kuzinzile, ubufakazi bokushaqeka, ukunciphisa umonakalo, kodwa futhi kungathola umphumela omuhle futhi omuhle ngaphakathi komshini.
Imishini emincane kufanele igcinwe ebangeni elithile eduze kwemishini ephezulu.Ibanga ledivayisi eliya esilinganisweni sobude bedivayisi lincane, kukhona igagasi elishisayo elingalingani, elingabangela ubungozi bokushisela okubi noma ukulungiswa ngemva kokushisela.
5.Isikhala sedivayisi kudivayisi
Ekucubunguleni i-smt evamile, kuyadingeka ukucabangela amaphutha athile ekufakweni komshini, futhi ucabangele ukunethezeka kokugcinwa nokuhlola okubukwayo.Izingxenye ezimbili eziseduze akufanele zisondele kakhulu futhi ibanga elithile eliphephile kufanele lishiywe.
Isikhala phakathi kwezingxenye ze-flake, i-SOT, i-SOIC nezingxenye ze-flake ngu-1.25mm.Isikhala phakathi kwezingxenye ze-flake, i-SOT, i-SOIC nezingxenye ze-flake ngu-1.25mm.2.5mm phakathi kwe-PLCC nezingxenye ze-flake, i-SOIC ne-QFP.4mm phakathi kwe-PLCCS.Lapho uklama amasokhethi e-PLCC, kufanele kuqashelwe ukuvumela ubukhulu besokhethi ye-PLCC (iphinikhodi ye-PLCC ingaphakathi ngaphansi kwesokhethi).
6.Ububanzi bomugqa/ibanga lomugqa
Kubaklami, ohlelweni lokuklama, asikwazi nje ukucabangela ukunemba nokuphelela kwezidingo zokuklama, kukhona ukuvinjelwa okukhulu yinqubo yokukhiqiza.Akunakwenzeka ukuthi imboni yebhodi idale umugqa omusha wokukhiqiza wokuzalwa komkhiqizo omuhle.
Ngaphansi kwezimo ezijwayelekile, ububanzi bomugqa womugqa owehlayo bulawulwa ukuze bufike ku-4/4mil, futhi imbobo ikhethwa ukuthi ibe ngu-8mil (0.2mm).Ngokuyisisekelo, ngaphezu kwe-80% yabakhiqizi be-PCB bangakhiqiza, futhi izindleko zokukhiqiza ziphansi kakhulu.Ububanzi obuncane bomugqa kanye nebanga lomugqa lingalawulwa libe ngu-3/3mil, futhi u-6mil (0.15mm) angakhethwa ngembobo.Ngokuyisisekelo, abakhiqizi be-PCB abangaphezu kuka-70% bangakwazi ukuyikhiqiza, kodwa intengo iphakeme kancane kunecala lokuqala, ayiphezulu kakhulu.
7.I-engeli ebukhali/i-engeli engakwesokudla
Umzila we-Engeli Ecijile ngokuvamile awuvunyelwe ezintamboni, umzila we-Engeli engakwesokudla ngokuvamile uyadingeka ukuze ugweme isimo emzileni we-PCB, futhi sekucishe kube enye yezindinganiso zokulinganisa ikhwalithi yezintambo.Ngenxa yokuthi ubuqotho besignali buthintekile, i-wiring ye-engeli engakwesokudla izokhiqiza amandla e-parasitic eyengeziwe kanye ne-inductance.
Enqubweni yokwenza amapuleti e-PCB, izintambo ze-PCB ziyaphambana nge-engeli ebukhali, okuzodala inkinga ebizwa nge-acid Angle.Ku-PCb circuit etching link, ukugqwala ngokweqile kwesekethe ye-pcb kuzobangelwa "i-Angle ye-asidi", okuholela enkingeni yekhefu le-PCB yesifunda.Ngakho-ke, onjiniyela be-PCB badinga ukugwema ama-engeli abukhali noma angajwayelekile kuzintambo, futhi bagcine i-Angle engu-45 degree ekhoneni lezintambo.
8.I-Copper strip/island
Uma kuyithusi elikhulu ngokwanele lesiqhingi, lizoba i-antenna, engabangela umsindo nokunye ukuphazamiseka ngaphakathi kwebhodi (ngoba ithusi layo aligxiliwe - lizoba umqoqi wesignali).
Imicu yethusi neziqhingi ziyizingqimba eziningi eziyisicaba zethusi elintantayo mahhala, ezingadala izinkinga ezinkulu emgodini we-asidi.Amabala ethusi amancane ayaziwa ngokuphula iphaneli ye-PCB futhi aye kwezinye izindawo ezigxilile kuphaneli, okubangela umjikelezo omfushane.
I-9.Indandatho yemigodi yemigodi yokubhoboza
Iringi yembobo isho iringi yethusi ezungeze umgodi wokubhoboza.Ngenxa yokubekezelelana enqubweni yokukhiqiza, ngemva kokubhoboza, ukucwiliswa, kanye nokucwecwa kwethusi, indandatho yethusi esele ezungeze umgodi wokubhoboza ayishayi kahle ngaso sonke isikhathi iphuzu eliphakathi nendawo lephedi, okungase kubangele ukuba indandatho yembobo iphuke.
Olunye uhlangothi lwendandatho yembobo kufanele lube lukhulu kuno-3.5mil, futhi iringi yembobo yepulaki kufanele ibe nkulu kuno-6mil.Iringi yembobo incane kakhulu.Enqubweni yokukhiqiza nokukhiqiza, imbobo yokumba inokubekezelela futhi ukulungiswa komugqa nakho kunokubekezelela.Ukuphambuka kokubekezelelana kuzoholela ekutheni indandatho yembobo iphule isifunda esivulekile.
10.Izinyembezi zehla izintambo
Ukwengeza izinyembezi kuzintambo ze-PCB kungenza uxhumano lwesifunda ebhodini le-PCB luzinze, luthembeke kakhulu, ukuze uhlelo luzinze, ngakho-ke kuyadingeka ukwengeza izinyembezi ebhodini lesifunda.
Ukwengezwa kwezinyembezi kungagwema ukunqanyulwa kwendawo yokuxhumana phakathi kwentambo nephedi noma ucingo kanye nembobo yokushayela lapho ibhodi lesekethe lithintwa amandla amakhulu angaphandle.Uma wengeza amaconsi ezinyembezi ekushiseleni, ingavikela iphedi, igweme ukushisela okuningi ukuze siwe iphedi, futhi igweme ukushumeka okungalingani kanye nokuqhekeka okubangelwa ukuchezuka kwembobo ngesikhathi sokukhiqiza.
