Ukushisa okukhiqizwa yimishini ye-elekthronikhi ngesikhathi sokusebenza kubangela ukuthi izinga lokushisa langaphakathi lemishini likhuphuke ngokushesha. Uma ukushisa kungaqedwa ngesikhathi, imishini izoqhubeka nokushisa, idivayisi izohluleka ngenxa yokushisa, futhi ukuthembeka kwemishini kagesi kuzokwehla. Ngakho-ke, kubaluleke kakhulu ukukhipha ukushisa ebhodini lesifunda.
I-Factor Analysis Yokukhuphuka Kwezinga lokushisa Kwebhodi Lesifunda Eliphrintiwe
Isizathu esiqondile sokukhuphuka kwezinga lokushisa kwebhodi eliphrintiwe kungenxa yokuba khona kwamadivayisi okusetshenziswa kwamandla wesekethe, futhi amadivaysi e-elekthronikhi anokusetshenziswa kwamandla kuya ngamazinga ahlukahlukene, futhi amandla okushisa ashintsha ngokusetshenziswa kwamandla.
Izimo ezimbili zokukhuphuka kwezinga lokushisa kumabhodi aphrintiwe:
(1) Ukwenyuka kwezinga lokushisa kwendawo noma ukukhuphuka kwezinga lokushisa endaweni enkulu;
(2) Ukukhuphuka kwezinga lokushisa kwesikhashana noma ukukhuphuka kwezinga lokushisa kwesikhathi eside.
Lapho uhlaziya ukusetshenziswa kwamandla ashisayo kwe-PCB, ngokuvamile kusuka kuzici ezilandelayo.
Ukusetshenziswa kwamandla kagesi
(1) Hlaziya ukusetshenziswa kwamandla endaweni yeyunithi ngayinye;
(2) Hlaziya ukusatshalaliswa kokusetshenziswa kwamandla ebhodini lesifunda le-PCB.
2. Isakhiwo sebhodi eliphrintiwe
(1) Ubukhulu bebhodi eliphrintiwe;
(2) Izinto zebhodi eliphrintiwe.
3. Indlela yokufaka ibhodi eliphrintiwe
(1) Indlela yokufaka (njengokufakwa okuqondile nokufakwa okuvundlile);
(2) Isimo sokuvala kanye nebanga ukusuka ebhokisini.
4. Emisebeni eshisayo
(1) Ukungabi nalutho kwendawo yebhodi ephrintiwe;
(2) Umehluko wokushisa phakathi kwebhodi eliphrintiwe nendawo eseduze nezinga lokushisa eliphelele;
5. Ukushisa kokushisa
(1) Faka irediyetha;
(2) Ukwenziwa kwezinye izingxenye zesakhiwo sokufakwa.
6. I-convection eshisayo
(1) Ukuhanjiswa kwemvelo;
(2) I-convection yokupholisa ephoqelelwe.
Ukuhlaziywa kwezici ezingenhla kusuka ku-PCB kuyindlela ephumelelayo yokuxazulula ukukhuphuka kwezinga lokushisa kwebhodi eliphrintiwe. Lezi zici zivame ukuhlobana futhi zincike emkhiqizweni kanye nohlelo. Izinto eziningi kufanele zihlaziywe ngokuya ngesimo sangempela, kuphela esimweni sangempela esithile. Kulesi simo kuphela lapho imingcele yokukhuphuka kwezinga lokushisa kanye nokusetshenziswa kwamandla kungabalwa noma kulinganiswe ngendlela efanele.
Indlela yokupholisa ibhodi lesifunda
1. Idivayisi ekhiqiza ukushisa okuphezulu kanye nesinki lokushisa kanye nepuleti le-heat conduction
Uma amadivaysi ambalwa ku-PCB ekhiqiza inani elikhulu lokushisa (ngaphansi kuka-3), isinki sokushisa noma ipayipi lokushisa lingangezwa kudivayisi ekhiqiza ukushisa. Uma izinga lokushisa lingenakwehliswa, isinki sokushisa esinefeni singasetshenziswa ukuthuthukisa umphumela wokuqeda ukushisa . Uma kunamadivayisi amaningi okushisa (okungaphezu kuka-3), isembozo esikhulu sokushisa (ibhodi) singasetshenziswa. Kuyirediyetha ekhethekile eyenziwe ngokwezifiso ngokuya ngokuma nokuphakama kwensiza yokushisisa ebhodini le-PCB noma kurediyetha enkulu eyisicaba Sika ubude bezingxenye ezihlukene. Bopha ikhava yokukhipha ukushisa endaweni engaphezulu, bese uthinta ingxenye ngayinye ukuze ukhiphe ukushisa. Kodwa-ke, ngenxa yokungaguquguquki okungalungile kwezingxenye ngesikhathi sokuhlanganiswa nokushisela, umphumela wokushisa ukushisa awumuhle. Ngokuvamile isigaba esithambile sokushintsha iphedi ye-thermal yengezwa endaweni yengxenye ukuze kuthuthukiswe umphumela wokulahla ukushisa.
2. Ukukhipha ukushisa ngebhodi le-PCB uqobo
Njengamanje, amapuleti e-PCB asetshenziswa kakhulu angama-copper-clad/epoxy glass cloth substrates noma ama-phenolic resin cloth cloth substrates, kanye nenani elincane lamapuleti agqoke ithusi asekelwe ephepheni. Nakuba lawa ma-substrates esebenza kahle kakhulu kagesi nokusebenza kokucubungula, anokukhipha ukushisa okungekuhle. Njengomzila okhipha ukushisa wezingxenye eziphezulu ezikhiqiza ukushisa, i-PCB ngokwayo ngeke ilindeleke ukuthi iqhube ukushisa kusuka ku-resin ye-PCB, kodwa ikhiphe ukushisa ukusuka phezulu kwengxenye kuya emoyeni ozungezile. Kodwa-ke, njengoba imikhiqizo ye-elekthronikhi ingene enkathini ye-miniaturization yezingxenye, ukufakwa kwe-high-density, nomhlangano wokushisa okuphezulu, akwanele ukuthembela ebusweni bezingxenye ezinendawo encane kakhulu ukuze kukhishwe ukushisa. Ngesikhathi esifanayo, ngenxa yokusetshenziswa okunzima kwezingxenye ezifakwe phezulu ezifana ne-QFP ne-BGA, ukushisa okukhiqizwa yizingxenye kudluliselwa ebhodini le-PCB ngobuningi. Ngakho-ke, indlela engcono kakhulu yokuxazulula ukuchithwa kokushisa ukuthuthukisa amandla okukhipha ukushisa kwe-PCB ngokwayo ngokuthintana okuqondile nento yokushisa. Yenza noma ukhiphe.
3. Yamukela idizayini yomzila ephusile ukuze uzuze ukunqanyulwa kokushisa
Ngenxa yokuthi ukuhanjiswa okushisayo kwe-resin eshidini kumpofu, futhi imigqa ye-foil yethusi nezimbobo zingabaqhubi abahle bokushisa, ukuthuthukisa izinga lokusalela le-foil yethusi nokwandisa izimbobo zokushisa ezishisayo kuyindlela eyinhloko yokushisa ukushisa.
Ukuze uhlole amandla okukhipha ukushisa kwe-PCB, kuyadingeka ukubala ukulinganisa kwe-thermal conductivity (i-eq eyisishiyagalolunye) yezinto ezihlanganisiwe ezakhiwe ngezinto ezihlukahlukene ezinama-coefficients ahlukene we-thermal conductivity-i-substrate evikelayo ye-PCB.
4. Okokusebenza okusebenzisa ukupholisa umoya we-convection wamahhala, kungcono ukuhlela amasekhethi ahlanganisiwe (noma amanye amadivaysi) ngokuma noma ngokuvundlile.
5. Amadivayisi ebhodini elifanayo eliphrintiwe kufanele ahlelwe ngokuvumelana nesizukulwane sawo sokushisa kanye nokukhishwa kokushisa ngangokunokwenzeka. Amadivayisi akhiqiza ukushisa okuncane noma ukumelana nokushisa okungekuhle (njengama-transistors wesignali amancane, amasekhethi ahlanganisiwe ezinga elincane, ama-electrolytic capacitor, njll.) abekwe ku-Umfula ophakeme kakhulu wokugeleza komoya okupholisa (ekungeneni), amadivayisi akhiqiza ukushisa okukhulu noma ukumelana nokushisa okuhle (njengama-transistors amandla, amasekhethi amakhulu ahlanganisiwe, njll.) abekwe endaweni ephansi kakhulu yokugeleza komoya okupholisa.
6. Esiqondisweni esivundlile, amadivaysi anamandla aphezulu kufanele abekwe eduze ngangokunokwenzeka emaphethelweni ebhodi eliphrintiwe ukuze afinyeze indlela yokudlulisa ukushisa; ohlangothini oluqondile, amadivaysi anamandla aphezulu kufanele abekwe eduze ngangokunokwenzeka phezulu kwebhodi eliphrintiwe ukuze kuncishiswe izinga lokushisa lawa madivaysi lapho usebenza kwamanye amadivaysi Impact.
7. Idivayisi ezwelayo kumazinga okushisa ibekwe kahle endaweni enezinga lokushisa eliphansi kakhulu (njengaphansi kwedivayisi). Ungalokothi uyibeke ngaphezu kwedivayisi ekhiqiza ukushisa. Amadivayisi amaningi anyakaziswa endizeni evundlile.
8. Ukushisa kokushisa kwebhodi eliphrintiwe kumishini ikakhulukazi kuncike ekugelezeni komoya, ngakho-ke indlela yokuhamba komoya kufanele ifundwe ekwakhiweni, futhi idivayisi noma ibhodi lesifunda eliphrintiwe kufanele lilungiswe ngokunengqondo. Lapho umoya ugeleza, uvame ukugeleza lapho ukumelana kuncane, ngakho-ke lapho ulungiselela amadivaysi ebhodini lesifunda eliphrintiwe, kuyadingeka ukugwema ukushiya isikhala esikhulu somoya endaweni ethile. Ukumiswa kwamabhodi esekethe aphrintiwe amaningi kuwo wonke umshini kufanele futhi kunake inkinga efanayo.
9. Gwema ukugcwala kwezindawo ezishisayo ku-PCB, sabalalisa amandla ngokulinganayo ku-PCB ngangokunokwenzeka, futhi ugcine ukusebenza kwezinga lokushisa kweyunifomu yangaphezulu ye-PCB futhi kungaguquki. Ngokuvamile kunzima ukufeza ukusatshalaliswa komfaniswano oqinile ohlelweni lokuklama, kodwa kuyadingeka ukugwema izindawo ezinomthamo omkhulu wamandla ukuze ugweme izindawo ezishisayo ezithinta ukusebenza okuvamile kwesifunda sonke. Uma izimo zivuma, ukuhlaziya ukusebenza kahle kokushisa kwamasekhethi aphrintiwe kuyadingeka. Isibonelo, amamojula esofthiwe yokuhlaziya inkomba yokusebenza kahle kwe-thermal engezwe kwenye isofthiwe yedizayini ye-PCB yobungcweti angasiza abaklami balungiselele ukwakheka kwesekethe.