Ubushushu obuveliswa zizixhobo zombane ngexesha lokusebenza kubangela ukuba ukushisa kwangaphakathi kwezixhobo kunyuke ngokukhawuleza. Ukuba ubushushu abuchithwanga ngexesha, izixhobo ziya kuqhubeka zifudumala, isixhobo siya kusilela ngenxa yokushisa, kwaye ukuthembeka kwezixhobo zombane kuya kuncipha. Ngoko ke, kubaluleke kakhulu ukukhupha ukushisa kwibhodi yesiphaluka.
IFactor Analysis yokunyuka koBubushushu beBhodi yeSekethe eprintiweyo
Isizathu esithe ngqo sokunyuka kweqondo lokushisa kwebhodi eprintiweyo kubangelwa ubukho bezixhobo zokusetyenziswa kwamandla esekethe, kunye nezixhobo zombane zinamandla okusebenzisa amandla ukuya kumaqondo ahlukeneyo, kwaye ubushushu buguquka ngokusetyenziswa kwamandla.
Iziganeko ezimbini zokunyuka kobushushu kwiibhodi eziprintiweyo:
(1) Ukunyuka kwamaqondo obushushu okanye ukunyuka kwamaqondo obushushu kwindawo enkulu;
(2) Ukunyuka kwexesha elifutshane lobushushu okanye ukunyuka kwexesha elide.
Xa kuhlalutywa PCB ukusetyenziswa kwamandla thermal, ngokubanzi ukusuka kule miba ilandelayo.
Ukusetyenziswa kwamandla ombane
(1) Ukuhlalutya ukusetyenziswa kwamandla ngokweyunithi yendawo nganye;
(2) Hlalutya ukuhanjiswa kokusetyenziswa kwamandla kwibhodi yesekethe yePCB.
2. Ubume bebhodi eprintiweyo
(1) Ubungakanani bebhodi eshicilelweyo;
(2) Izinto zebhodi eprintiweyo.
3. Indlela yokufakela ibhodi eprintiweyo
(1) Indlela yokufakela (njengofakelo oluthe nkqo kunye nofakelo oluthe tye);
(2) Imeko yokutywina kunye nomgama ukusuka kwibhokisi.
4. Imitha yokushisa
(1) Ukungabikho komgangatho webhodi eprintiweyo;
(2) Umahluko weqondo lobushushu phakathi kwebhodi eprintiweyo kunye nomgangatho osecaleni kunye nobushushu bazo obupheleleyo;
5. Ukuqhuba kobushushu
(1) Fakela iradiyetha;
(2) Ukwenziwa kwezinye iindawo zesakhiwo sofakelo.
6. I-Thermal convection
(1) Ukuhanjiswa kwendalo;
(2) Ukupholisa okunyanzelweyo.
Uhlalutyo lwezi zinto zingentla kwi-PCB yindlela efanelekileyo yokusombulula ukunyuka kobushushu bebhodi eprintiweyo. Ezi zinto zihlala zihambelana kwaye zixhomekeke kwimveliso kunye nenkqubo. Uninzi lwezinto kufuneka zihlalutywe ngokweyona meko, kuphela kwimeko yokwenyani. Kule meko kuphela apho iiparameters zokunyuka kweqondo lokushisa kunye nokusetyenziswa kwamandla zibalwe okanye ziqikelelwe ngokuchanekileyo.
Indlela yokupholisa ibhodi yesekethe
1. Isixhobo esivelisa ubushushu obuphezulu kunye nesinki yobushushu kunye nepleyiti yokuqhuba ubushushu
Xa izixhobo ezimbalwa kwi-PCB zivelisa ubushushu obukhulu (ngaphantsi kwe-3), isitya sokushisa okanye umbhobho wokushisa unokongezwa kwisixhobo sokuvelisa ukushisa. Xa iqondo lobushushu lingenako ukuthotywa, isinki sobushushu esinefeni singasetyenziselwa ukomeleza isiphumo sokuphelisa ubushushu. Xa kukho izixhobo zokufudumeza ezininzi (ngaphezu kwe-3), isigqubuthelo esikhulu sokutshatyalaliswa kobushushu (ibhodi) singasetyenziswa. Yiradiyetha ekhethekileyo elungiselelwe ngokwendawo kunye nokuphakama kwesixhobo sokufudumeza kwibhodi yePCB okanye kwiradiyetha enkulu eflethi Sika ubude bamacandelo ahlukeneyo. Gxininisa isigqubuthelo sokutshatyalaliswa kobushushu kumphezulu wecandelo, kwaye uqhagamshelane necandelo ngalinye ukuze uchithe ubushushu. Nangona kunjalo, ngenxa yokungahambi kakuhle kwamacandelo ngexesha lokudibanisa kunye ne-welding, umphumo wokutshatyalaliswa kobushushu awulungile. Ngokuqhelekileyo isigaba esithambileyo sokutshintsha i-thermal pad yongezwa kwindawo yecandelo ukuphucula umphumo wokutshatyalaliswa kobushushu.
2. Ukutshatyalaliswa kobushushu ngebhodi yePCB ngokwayo
Okwangoku, iipleyiti ze-PCB ezisetyenziswa ngokubanzi zi-copper-clad/epoxy glasscloth substrates okanye i-phenolic resin glass cloth substrates, kunye nenani elincinci leepleyiti zobhedu ezisekelwe ephepheni ziyasetyenziswa. Nangona ezi substrates zinentsebenzo egqwesileyo yombane kunye nokusebenza kokulungiswa, zinobuthontsi obumdaka. Njengendlela yokuphelisa ubushushu yamacandelo aphezulu avelisa ubushushu, iPCB ngokwayo ayinakulindeleka ukuba iqhube ubushushu obusuka kwintlaka yePCB, kodwa ikhuphe ubushushu ukusuka kumphezulu wecandelo ukuya kumoya ojikelezileyo. Nangona kunjalo, njengoko iimveliso ze-elektroniki ziye zangena kwixesha le-miniaturization yamacandelo, ukufakwa kwe-high-density, kunye ne-high-heat assembly, akwanele ukuthembela kumphezulu wamacandelo kunye nommandla omncinci kakhulu wokukhupha ukushisa. Ngelo xesha, ngenxa yokusetyenziswa okunzima kwamacandelo afakwe phezulu njenge-QFP kunye ne-BGA, ubushushu obuveliswa ngamacandelo budluliselwa kwibhodi ye-PCB ngobuninzi. Ngoko ke, eyona ndlela ilungileyo yokusombulula ukutshatyalaliswa kobushushu kukuphucula amandla okutshatyalaliswa kobushushu bePCB ngokwayo ngokudibana ngokuthe ngqo nento yokufudumeza. Yenza okanye ukhuphe.
3. Yamkela uyilo olufanelekileyo lwendlela ukufezekisa ukutshabalalisa ubushushu
Ngenxa yokuba i-thermal conductivity ye-resin ephepheni ihlwempuzekile, kwaye imigca yefoyile yobhedu kunye nemingxuma ziziqhubi ezilungileyo zobushushu, ukuphucula izinga lentsalela yefoyile yobhedu kunye nokwandisa imingxuma yokuqhuba i-thermal zezona ndlela ziphambili zokutshatyalaliswa kobushushu.
Ukuvavanya amandla okutshatyalaliswa kobushushu be-PCB, kuyimfuneko ukubala i-conductivity ye-thermal elinganayo (i-eq elithoba) yezinto ezihlanganisiweyo ezenziwe ngezinto ezahlukeneyo kunye ne-thermal conductivity coefficients-i-insulating substrate ye-PCB.
4. Kwizixhobo ezisebenzisa i-cooling convection air free, kungcono ukulungiselela iisekethe ezidibeneyo (okanye ezinye izixhobo) ngokuthe ngqo okanye ngokuthe tye.
5. Izixhobo ezikwibhodi eprintiweyo efanayo kufuneka zicwangciswe ngokuhambelana nokuveliswa kobushushu kunye nokutshatyalaliswa kobushushu kangangoko kunokwenzeka. Izixhobo ezinesizukulwana esincinci sobushushu okanye ukunganyangeki kobushushu (ezifana neetransistors zomqondiso omncinci, iisekethe ezincinci ezihlanganisiweyo, i-electrolytic capacitors, njl.njl.) zibekwe Kuwona mlambo uphezulu wokupholisa umoya (ekungeneni), izixhobo ezinesizukulwana esikhulu sobushushu okanye ukumelana nobushushu obuhle (njengama-transistors amandla, iisekethe ezinkulu ezihlanganisiweyo, njl.njl.) zibekwe kwezona ndawo zisezantsi zomoya opholileyo.
6. Kwisalathiso esithe tye, izixhobo eziphezulu zamandla kufuneka zibekwe ngokusondeleyo kumda webhodi eprintiweyo ukunciphisa umzila wokushisa ukushisa; kwicala elithe nkqo, izixhobo eziphezulu zamandla kufuneka zibekwe ngokusondeleyo kangangoko kunokwenzeka kumphezulu webhodi eprintiweyo ukunciphisa ubushushu bezi zixhobo xa usebenza kwezinye izixhobo Impact.
7. Isixhobo esingeva ngeqondo lobushushu sibekwe kakuhle kwindawo eneqondo lobushushu elisezantsi (njengamazantsi esixhobo). Ungaze uyibeke phezu kwesixhobo esivelisa ubushushu. Izixhobo ezininzi zikhethwa ukuba zigxadazele kwinqwelomoya ethe tye.
8. Ukutshatyalaliswa kobushushu bebhodi eprintiweyo kwisixhobo ngokuyinhloko kuxhomekeke ekuhambeni komoya, ngoko ke indlela yokuhamba komoya kufuneka ifundwe kuyilo, kwaye isixhobo okanye ibhodi yesekethe eprintiweyo kufuneka iqwalaselwe ngokufanelekileyo. Xa umoya uhamba, uhlala udla ngokuhamba apho ukuchasana kuncinci, ngoko ke xa ulungiselela izixhobo kwibhodi yesekethe eprintiweyo, kuyimfuneko ukuphepha ukushiya indawo enkulu yomoya kwindawo ethile. Ukucwangciswa kweebhodi zeesekethe ezininzi eziprintiweyo kuwo wonke umatshini kufuneka kwakhona ingqalelo ingxaki efanayo.
9. Kuphephe ukuxinana kweendawo ezishushu kwi-PCB, usasaze amandla ngokulinganayo kwi-PCB kangangoko kunokwenzeka, kwaye ugcine ubushushu bokusebenza kweyunifomu yomphezulu we-PCB kwaye ihambelana. Ngokuqhelekileyo kunzima ukufezekisa ukusabalalisa okufanayo ngokungqongqo kwinkqubo yoyilo, kodwa kuyimfuneko ukuphepha iindawo ezinobunzima obukhulu kakhulu ukuphepha iindawo ezishushu ezichaphazela ukusebenza okuqhelekileyo kwesekethe yonke. Ukuba iimeko zivumela, uhlalutyo olusebenzayo lwe-thermal yeesekethe eziprintiweyo luyimfuneko. Umzekelo, iimodyuli zesoftware yohlalutyo olusebenzayo lobushushu ezongeziweyo kwisoftware yoyilo lwePCB yobuchwephesha inokunceda abaqulunqi baphucule uyilo lwesekethe.