Ishicilelwe ibhodi yesekethe ngumboneleli woqhagamshelo lombane kumalungu e-elektroniki. Ukuphuhliswa kwayo kunembali engaphezu kweminyaka eyi-100; uyilo lwayo ikakhulu uyilo loyilo; inzuzo ephambili yokusebenzisa iibhodi zeesekethe kukunciphisa kakhulu iimpazamo ze-wiring kunye nendibano, kunye nokuphucula izinga lokuzenzekelayo kunye nesantya somsebenzi wemveliso. Ngokutsho kwenani leebhodi zesekethe, inokwahlulwa ibe ngamabhodi asecaleni elinye, iibhodi ezinamacala amabini, iibhodi ezine, iibhodi ezithandathu kunye nezinye iibhodi zeesekethe ezininzi.

Ekubeni ibhodi yesekethe eprintiweyo ayiyona imveliso yesiphelo jikelele, inkcazo yegama ibhideka kancinane. Ngokomzekelo, i-motherboard yeekhomputha zomntu ibizwa ngokuba yibhodi ephambili, kwaye ayikwazi ukubizwa ngokuba yibhodi yesiphaluka ngokuthe ngqo. Nangona kukho iibhodi zeesekethe kwi-motherboard, azifani, ngoko xa kuhlolwa ishishini, ezi zimbini zihlobene kodwa azinakuthi zifana. Omnye umzekelo: kuba kukho iinxalenye zesekethe ezidibeneyo ezifakwe kwibhodi yesekethe, iindaba zeendaba zibiza ngokuba yibhodi ye-IC, kodwa ngokwenene ayifani nebhodi yesekethe eprintiweyo. Ngokuqhelekileyo sithi ibhodi yesekethe eprintiweyo ibhekisela kwibhodi engenanto-oko kukuthi, ibhodi yesiphaluka ngaphandle kwamacandelo aphezulu. Kwinkqubo yoyilo lwebhodi ye-PCB kunye nokuveliswa kwebhodi yesekethe, iinjineli azifuneki kuphela ukuthintela iingozi kwinkqubo yokwenziwa kwebhodi yePCB, kodwa kufuneka ziphephe iimpazamo zoyilo.

Ingxaki 1: Ibhodi yesekethe isiphaluka esifutshane: Kulo hlobo lwengxaki, yenye yeempazamo eziqhelekileyo eziza kubangela ukuba ibhodi yesekethe ingasebenzi. Esona sizathu sikhulu sesekethe emfutshane yebhodi yePCB kuyilo lwephedi ye-solder engafanelekanga. Ngeli xesha, unokutshintsha i-solder pad ejikelezayo kwi-oval. Ubume, ukwandisa umgama phakathi kwamanqaku ukuthintela imijikelezo emfutshane. Uyilo olungafanelekanga lwesalathiso samalungu obungqina be-PCB nawo aya kubangela ukuba ibhodi ibe yimfutshane kwaye isilele ukusebenza. Umzekelo, ukuba i-pin ye-SOIC ihambelana ne-tin wave, kulula ukwenza ingozi ye-short-circuit. Ngeli xesha, ulwalathiso lwenxalenye lunokuguqulwa ngokufanelekileyo ukuze luyenze i-perpendicular kumaza e-tin. Kukho enye into enokuthi ibangele ukusilela kwesekethe emfutshane yePCB, oko kukuthi, unyawo olujijekileyo lweplagi oluzenzekelayo. Njengoko i-IPC ichaza ukuba ubude bepini bungaphantsi kwe-2mm kwaye kukho inkxalabo yokuba iindawo ziya kuwa xa i-angle yomlenze ogobileyo inkulu kakhulu, kulula ukubangela isiphaluka esifutshane, kwaye i-solder joint kufuneka ibe ngaphezulu. ngaphezu kwe-2mm kude nesekethe.

Ingxaki yesi-2: Amalungu e-solder e-PCB abe bugolide tyheli: Ngokubanzi, i-solder kwiibhodi zeesekethe ze-PCB isilivere-ngwevu, kodwa ngamanye amaxesha kukho iindawo zokuhlanganisa zegolide. Esona sizathu sale ngxaki kukuba ubushushu buphezulu kakhulu. Ngeli xesha, kufuneka unciphise kuphela ukushisa kwesithando somlilo.

Ingxaki yesi-3: Uqhagamshelwano olumnyama kunye ne-granular luvela kwibhodi yesekethe: Uqhagamshelwano olumnyama okanye oluncinci luvela kwi-PCB. Uninzi lweengxaki zibangelwa ukungcoliswa kwe-solder kunye nee-oxides ezigqithisileyo ezixutywe kwi-tin etyhidiweyo, eyenza i-solder joint structure. crisp. Qaphela ukuba ungayidibanisi nombala omnyama obangelwa ukusetyenziswa kwe-solder enomxholo ophantsi we-tin. Esinye isizathu sale ngxaki kukuba ukubunjwa kwe-solder esetyenziswe kwinkqubo yokuvelisa kutshintshile, kwaye umxholo wokungcola uphezulu kakhulu. Kuyimfuneko ukongeza i-tin ecocekileyo okanye indawo ye-solder. Iglasi engcolileyo ibangela utshintsho olubonakalayo kwi-fiber build-up, njengokwahlula phakathi kweeleya. Kodwa le meko ayikho ngenxa yokungahambi kakuhle kwe-solder. Isizathu kukuba i-substrate ishushu kakhulu, ngoko kuyimfuneko ukunciphisa ukushisa kwangaphambili kunye ne-soldering okanye ukwandisa isantya se-substrate.

Ingxaki yesi-4: Amacandelo e-PCB akhululekileyo okanye alahlekileyo: Ngexesha lenkqubo yokuphinda ithengise i-reflow, iindawo ezincinci zinokudada kwi-solder etyhidiweyo kwaye ekugqibeleni ziyishiye i-solder ekujoliswe kuyo. Izizathu ezinokwenzeka zokufuduka okanye ukuthambeka ziquka ukungcangcazela okanye ukugxumeka kwamacandelo kwibhodi ye-PCB ethengisiweyo ngenxa yenkxaso enganeleyo yebhodi yesekethe, izicwangciso ze-oven reflow, iingxaki ze-solder paste, kunye nempazamo yomntu.

Ingxaki yesi-5: Ibhodi yesekethe evulekileyo yesiphaluka: Xa umkhondo uphukile, okanye i-solder ikwi-pad kuphela kwaye ingekho kwi-lead yecandelo, isiphaluka esivulekileyo siya kwenzeka. Kule meko, akukho kunamathela okanye unxibelelwano phakathi kwecandelo kunye nePCB. Njengeesekethe ezimfutshane, ezi zinokuthi zenzeke ngexesha lenkqubo yokuvelisa okanye ngexesha lenkqubo ye-welding kunye neminye imisebenzi. Ukungcangcazela okanye ukunweba kwebhodi yesekethe, ukuwayeka okanye ezinye izinto zokuguqulwa komatshini ziya kutshabalalisa umkhondo okanye i-solder joints. Ngokufanayo, iikhemikhali okanye ukufuma kunokubangela ukuba i-solder okanye iinxalenye zetsimbi zinxibe, ezinokubangela ukuba icandelo likhokelela ekuphuleni.

Ingxaki yesi-6: Iingxaki ze-Welding: Ezi zilandelayo ziingxaki ezibangelwa yi-welding engafanelekanga: Ukuphazamiseka kwe-solder joints: Ngenxa yokuphazamiseka kwangaphandle, i-solder ihamba ngaphambi kokuqina. Oku kufana neendawo ezibandayo ze-solder, kodwa isizathu sahlukile. Inokulungiswa ngokufudumeza kwakhona, kwaye i-solder joints ayiphazanyiswa ngaphandle xa ipholile. I-Cold welding: Le meko iyenzeka xa i-solder ingakwazi ukunyibilika ngokufanelekileyo, okubangelwa iindawo ezinqabileyo kunye nokudibanisa okungathembekiyo. Ekubeni i-solder egqithisileyo ithintela ukunyibilika okupheleleyo, amajoyina abandayo anokuthi avele. Isilungiso kukubuyisela ukudibanisa kunye nokususa i-solder engaphezulu. Ibhulorho ye-Solder: Oku kwenzeka xa i-solder iwela kwaye idibanisa ngokomzimba iinkokeli ezimbini kunye. Ezi zinokwenza unxibelelwano olungalindelekanga kunye neesekethe ezimfutshane, ezinokubangela ukuba amacandelo atshise okanye atshise imikhondo xa umsinga uphezulu kakhulu. Ukumanzisa okungonelanga kweepads, izikhonkwane, okanye ii lead. I-solder eninzi kakhulu okanye encinci kakhulu. Iipads eziphakanyisiweyo ngenxa yokushisa kakhulu okanye i-soldering erhabaxa.

Ingxaki yesi-7: Ububi bebhodi ye-pcb buchaphazeleka nokusingqongileyo: ngenxa yesakhiwo sePCB ngokwayo, xa kwindawo engathandekiyo, kulula ukubangela umonakalo kwibhodi yesiphaluka. Ukushisa okugqithisileyo okanye ukuguquguquka kwamaqondo obushushu, ukufuma okugqithisileyo, ukungcangcazela okuphezulu kunye nezinye iimeko zonke ezi zinto zibangela ukuba ukusebenza kwebhodi kunciphe okanye kude kube lula. Ngokomzekelo, utshintsho kwiqondo lokushisa elisezantsi luya kubangela ukuguqulwa kwebhodi. Ngoko ke, iintambo ze-solder ziya kutshatyalaliswa, ukubunjwa kwebhodi kuya kugoba, okanye imikhondo yobhedu ebhodini ingaphulwa. Ngakolunye uhlangothi, ukufuma emoyeni kunokubangela i-oxidation, i-corrosion kunye ne-rust kumphezulu wesinyithi, njengemikhondo yobhedu eveziweyo, i-solder joints, iipads, kunye neendawo zokukhokela. Ukuqokelelwa kokungcola, uthuli okanye inkunkuma kumphezulu wamacandelo kunye neebhodi zeesekethe kunokunciphisa ukuhamba komoya kunye nokupholisa kwamacandelo, okubangela ukufudumeza kwe-PCB kunye nokunciphisa ukusebenza. Ukungcangcazela, ukuwa, ukubetha okanye ukugoba i-PCB kuya kuyikhubaza kwaye kubangele ukuba kubonakale ukuqhekeka, ngelixa i-high current okanye i-overvoltage iya kubangela ukuba i-PCB iphulwe okanye ibangele ukuguga ngokukhawuleza kwamacandelo kunye neendlela.

Umbuzo 8: Impazamo yomntu: Uninzi lweziphene ekwenziweni kwePCB zibangelwa yimpazamo yomntu. Kwiimeko ezininzi, inkqubo yemveliso engalunganga, ukubekwa kwamacandelo ngendlela engeyiyo kunye neenkcukacha zokwenziwa ngendlela engafanelekanga kunokubangela ukuya kuma-64% ukunqanda ukuvela kweziphene zemveliso.