Sezvo saizi yePCBA zvikamu zviri kuita zvidiki uye zvidiki, density iri kuramba ichikwira nekukwira; Kureba pakati pemidziyo nemidziyo (pitch/ground clearance pakati pePCB nePCB) iri kuitawo diki nediki, uye pesvedzero yezvakatipoteredza zvinhu paPCBA iri kuwedzerawo, saka tinoisa pamberi pepamusoro zvinodiwa pakuvimbika. zvemagetsi zvigadzirwa PCBA.
PCBA zvikamu kubva kuhombe kusvika kudiki, kubva padiki kusvika kune dense shanduko maitiro
Zvinhu zvakatipoteredza nemigumisiro yazvo
Zvakajairwa zvakatipoteredza zvinhu zvakaita sehunyoro, guruva, munyu pfapfaidzo, mold, nezvimwe, zvinokonzeresa matambudziko akasiyana ekutadza kwePCBA
Humidity munharaunda yekunze yemagetsi PCB zvikamu, zvinenge zvese pane njodzi yekuora, iyo mvura ndiyo inonyanya kukosha svikiro, mamorekuru emvura madiki zvekupinda mukati memesh molecular gap yezvimwe zvinhu zvepolymer mukati kana kuburikidza. mapini ekuputira kuti asvike pasi pesimbi ngura. Kana mhepo yasvika kune imwe humidity, inogona kukonzera PCB electrochemical migration, kuvuza ikozvino uye kukanganiswa kwechiratidzo mumaseketi akakwira-frequency.
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Mhepo / mwando + ionic zvinosvibisa (munyu, flux inoshanda vamiririri) = conductive electrolyte + stress voltage = electrochemical migration
Apo RH mumhepo inosvika 80%, pachava ne5 kusvika ku20 mamorekuru emvura yakakora firimu, marudzi ose emamorekuru anogona kusununguka kufamba, kana pane carbon, inogona kubudisa electrochemical reaction; Kana RH yasvika 60%, iyo yepamusoro yemidziyo inoumba firimu remvura rine ukobvu hwe2 kusvika ku4 mamorekuru emvura, uye makemikari anozoitika kana zvinosvibisa zvanyungudika mairi. Kana RH <20% mumhepo, zvinenge zvese zviitiko zvekuora zvinomira;
Naizvozvo, kudzivirira hunyoro chikamu chakakosha chekuchengetedzwa kwechigadzirwa.
Pamidziyo yemagetsi, hunyoro hunouya nenzira nhatu: mvura, condensation, uye mhute yemvura. Mvura ielectrolyte inogona kunyungudutsa maion anoparadza akawanda anoparadza simbi. Kana tembiricha yechimwe chikamu chemidziyo iri pazasi pe "dova point" (tembiricha), pachava nekudzikama pamusoro pepamusoro: zvikamu zvechimiro kana PCBA.
huruva
Kune guruva mumhepo, uye guruva rinoshambadza ion zvinosvibisa kuti zvigare mukati memidziyo yemagetsi uye kukonzera kukundikana. Ichi chinhu chakajairika chekutadza kwemagetsi mumunda.
Guruva rakakamurwa kuva marudzi maviri: guruva rakakora risingaenzaniswi zvimedu zvine dhayamita ye2.5 kusvika ku15 microns, iyo kazhinji isingakonzerese matambudziko akadai sekukundikana, arc, asi inokanganisa kubata kwechibatanidza; Hupfu hwakatsetseka zvidimbu zvisingaenzaniswi zvine dhayamita isingasviki 2.5 microns. Guruva rakanaka rine kumwe kunamatira paPCBA (veneer) uye rinogona kubviswa nemabhurashi anopikisa.
Njodzi dzeguruva: a. Nekuda kweguruva rinogadzika pamusoro pePCBA, electrochemical corrosion inogadzirwa, uye chiyero chekutadza chinowedzera; b. Guruva + kunyorova kupisa + munyu pfapfaidzo ine kukuvara kukuru kwePCBA, uye kukundikana kwemidziyo yemagetsi ndiko kwakanyanya mumahombekombe, gwenga (saline-alkali nyika), uye indasitiri yemakemikari nenzvimbo dzemigodhi pedyo neRwizi Huaihe panguva yekuvhuvhu uye mwaka wemvura. .
Nokudaro, kudzivirira guruva chikamu chinokosha chekuchengetedzwa kwezvigadzirwa.
Kupfapfaidza munyu
Kuumbwa kwemunyu wekupfapfaidza: munyu wekupfapfaidza unokonzerwa nezvinhu zvechisikigo zvakaita semafungu, masaisai uye kutenderera kwemhepo (monsoon) kudzvanywa, kupenya kwezuva, uye kuchawira mukati menyika nemhepo, uye kunyura kwayo kunodzikira nechinhambwe kubva kumahombekombe, kazhinji 1Km kubva. mhenderekedzo yegungwa i1% yemhenderekedzo yegungwa (asi dutu richaramba richiwedzera).
Kukuvadza kwemunyu wekupfapfaidza: a. kukanganisa kuvharwa kwezvikamu zvesimbi; b. Yakawedzera electrochemical corrosion rate inotungamira kune simbi waya kuputsika uye kutadza kwechikamu.
Kufanana kunobva ngura: a. Iko kune munyu, urea, lactic acid uye mamwe makemikari ari muruoko ziya, izvo zvakafanana corrosive mhedzisiro pamidziyo yemagetsi sezvo munyu pfapfaidzo, saka magirovhosi anofanira kupfekwa panguva gungano kana kushandiswa, uye kupfeka haafanire kubatwa nemaoko asina; b. Kune ma halogens uye maasidhi mumhepo inoyerera, iyo inofanirwa kucheneswa uye iyo yakasara yekuisa inodzorwa.
Naizvozvo, kudzivirira kupfapfaidza munyu chikamu chakakosha chekuchengetedzwa kwechigadzirwa.
mold
Ukuva, iro zita rinowanzozivikanwa refilamentous fungi, rinoreva kuti "fungus" rinowanzoita mycelium yakasvibirira, asi isingaburitse miviri mikuru inobereka sehowa. Munzvimbo dzakanyorova uye dzinodziya, zvinhu zvakawanda zvinokura zvinooneka fluff, flocculent kana spider colonies, iri mold.
PCB mold chiitiko
Kukuvadza kwe mold: a. mold phagocytosis uye kupararira kunoita kuti kuvharwa kwezvinhu zvipenyu kuderera, kukuvadzwa uye kukundikana; b. Iyo metabolites ye mold ndeye organic acids, iyo inokanganisa kusungirirwa uye kupikisa kwemagetsi uye kuburitsa arc.
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Nokudaro, anti-mold chikamu chinokosha chekuchengetedzwa kwezvigadzirwa.
Tichifunga nezvezvinhu zviri pamusoro apa, kuvimbika kwechigadzirwa kunofanirwa kuve kwakavimbiswa zviri nani, uye kunofanirwa kuve kwakaparadzaniswa nekunze kwekunze zvakaderera sezvinobvira, saka maitiro ekuputira chimiro anounzwa.
Mushure mekuputira maitiro ePCB, iyo yekupfura mhedzisiro pasi pemwenje wepepuru, iyo yepakutanga yekupfekedza inogona zvakare kuve yakanaka kwazvo!
Matatu e-anti-pendi coating inoreva iyo PCB yepamusoro yakavharwa neyakatetepa yekudzivirira yekudzivirira layer, parizvino ndiyo inonyanya kushandiswa post-welding yekumusoro coating nzira, dzimwe nguva inozivikanwa seyepamusoro coating, coating shape coating (zita rechirungu coating, conformal coating. ). Inoparadzanisa zvinhu zvemagetsi zvinonzwisisika kubva munzvimbo dzakaomarara, inovandudza zvakanyanya kuchengetedzwa uye kuvimbika kwezvigadzirwa zvemagetsi uye kuwedzera hupenyu hwesevhisi yezvigadzirwa. Tri-resistant coatings inodzivirira maseketi / zvikamu kubva kune zvakatipoteredza zvinhu zvakaita sehunyoro, zvinosvibisa, ngura, kushushikana, kuvhunduka, mechanical vibration uye thermal cycling, ukuwo uchivandudza simba remakanika uye insulation zvimiro zvechigadzirwa.
Mushure mekugadzirisa, PCB inoumba firimu rekudzivirira rakajeka pamusoro pepamusoro, iro rinogona kudzivirira kupindira kwemabheji emvura uye unyoro, kudzivisa kubuda uye kupfupika.
2. Pfungwa huru dzekuputira nzira
Zvinoenderana nezvinodiwa zve IPC-A-610E (Electronic Assembly Testing Standard), inonyanya kuratidzwa mune zvinotevera zvinhu.
Complex PCB board
1. Nzvimbo dzisingagone kuvharwa:
Nzvimbo dzinoda kubatanidza magetsi, dzakaita semapadhi egoridhe, zvigunwe zvegoridhe, simbi nemumaburi, maburi ebvunzo; Mabhatiri uye bhatiri mounts; Connector; Fuse uye dzimba; Chigadzirwa chekupisa kupisa; Jumper wire; Lenses yezvigadzirwa zvemaziso; Potentiometer; Sensor; Hapana switch yakavharwa; Dzimwe nzvimbo uko kupfeka kunogona kukanganisa kushanda kana kushanda.
2. Nzvimbo dzinofanirwa kuvharwa: majoini ese solder, mapini, component conductors.
3. Nzvimbo dzinogona kuvezwa kana kwete
ukobvu
Ukobvu hunoyerwa pane yakati sandara, isingadzivirirwe, yakaporeswa pamusoro pechikamu chakadhindwa chedunhu, kana pandiro yekunamatira inopinda mukugadzira nechikamu. Bhodhi rakabatanidzwa rinogona kunge riri rezvinhu zvakafanana nebhodhi rakadhindwa kana zvimwe zvinhu zvisina porous, zvakadai sesimbi kana girazi. Wet firimu ukobvu kuyerwa kunogona zvakare kushandiswa seyakasarudzika nzira yekuputira ukobvu kuyerwa, chero hukama hwekushandura pakati pekuoma uye kunyorova kwefirimu ukobvu hwakanyorwa.
Tafura 1: Hukobvu renji chiyero kune yega yega yemhando yekupfekedza zvinhu
Ukobvu bvunzo nzira:
1. Dry firimu ukobvu kuyera chishandiso: micrometer (IPC-CC-830B); b Dry Film Thickness Gauge (Iron base)
Micrometer yakaoma firimu chiridzwa
2. Kuyera kwefirimu kuyera kuyerwa: Ukobvu hwefirimu rakanyorova hunogona kuwanikwa neyakanyorova firimu ukobvu geji, uye wozoverengerwa nechikamu cheglue solid content.
Ukobvu hwefirimu yakaoma
Iyo yakanyorova firimu ukobvu inowanikwa neyakanyorova firimu ukobvu gauge, uye ipapo yakaoma firimu ukobvu inoverengwa
Edge resolution
Tsanangudzo: Mumamiriro ezvinhu akajairwa, iyo spray valve spray kunze kwemutsetse wemutsara haizonyatso kutwasuka, pachagara paine imwe burr. Isu tinotsanangura hupamhi hweburr sechigadziriso chemupendero. Sezvinoratidzwa pazasi, saizi ye d kukosha kwekugadziriswa kwemupendero.
Ongorora: Kugadziriswa kwemupendero ndiko kudiki kuri nani, asi zvakasiyana zvinodiwa nevatengi hazvina kufanana, saka iyo chaiyo yakavharidzirwa kumucheto resolution chero inosangana nezvinodiwa nevatengi.
Edge resolution kuenzanisa
Kufanana, guruu rinofanira kunge rakafanana nehupamhi hweyunifomu uye firimu rakatsetseka rakavharwa pachigadzirwa, kusimbiswa kuri pakufanana kweglue yakavharwa muchigadzirwa chiri pamusoro penzvimbo, zvino inofanira kunge yakafanana nehupamhi, hapana matambudziko ekugadzirisa: kutsemuka, stratification, mitsetse orenji, kusvibiswa, capillary chiitiko, mabhuru.
Axis otomatiki AC akateedzera otomatiki yekuputira muchina wekupfeka maitiro, kufanana kunowirirana zvakanyanya
3. Nzira yekuziva nzira yekuputira uye nzira yekuputira
Danho 1 Gadzirira
Gadzirira zvigadzirwa uye glue nezvimwe zvinhu zvinodiwa; Sarudza nzvimbo yekuchengetedzwa kwenzvimbo; Sarudza ruzivo rwakakosha rwekuita
Danho 2 Geza
Inofanira kucheneswa mukati menguva pfupi mushure mekuputika kuitira kudzivirira tsvina yekutsvaira kubva pakuoma kuchenesa; Sarudza kana iyo huru inosvibisa i polar kana isiri-polar kuitira kuti usarudze akakodzera kuchenesa mumiririri; Kana doro rekuchenesa agent rinoshandiswa, nyaya dzekuchengetedza dzinofanira kubhadharwa kune: panofanira kuva nemhepo yakanaka uye kutonhora uye kuomesa maitiro emitemo mushure mekugeza, kudzivirira kusara kwekunyungudika kwemhepo kunokonzerwa nekuputika muchoto; Mvura yekuchenesa, geza iyo flux nealkaline yekuchenesa mvura (emulsion), uye wozogeza mvura yekuchenesa nemvura yakachena kuti isangane nechiyero chekuchenesa;
3. Masking kudzivirira (kana yakasarudzwa yekupfekedza midziyo isingashandisi), kureva, mask;
Inofanira kusarudza isina-adhesive firimu haizotamisa bepa tepi; Anti-static bepa tepi inofanira kushandiswa kudzivirira IC; Zvinoenderana nezvinodiwa zvekudhirowa, mimwe michina inodzivirirwa;
4.Dehumidify
Mushure mekuchenesa, iyo yakadzivirirwa PCBA (chikamu) inofanira kunge isati yaomeswa uye yakasvibiswa isati yapfeka; Sarudza tembiricha / nguva pre-kuomesa maererano tembiricha inobvumirwa PCBA (chikamu);
Tafura 2: PCBA (zvikamu) zvinogona kubvumirwa kuona tembiricha / nguva yepre-drying table
Danho 5 Nyorera
Iyo nzira yekupfekedza inoenderana nePCBA kuchengetedza zvinodiwa, iyo iripo process midziyo uye iripo tekinoroji matura, ayo anowanzo kuwanikwa nenzira dzinotevera:
a. Geza neruoko
Hand pendi nzira
Brush coating ndiyo inonyanya kushanda maitiro, akakodzera diki batch kugadzirwa, PCBA chimiro chakaomarara uye chakaonda, chinoda kuchengetedza zvinodiwa zvekuchengetedza zvigadzirwa zvine hutsinye. Nemhaka yokuti kukwesha kunogona kudzora kupfekedza pamadiro, zvikamu zvisingabvumirwi kupendwa hazvizosvibiswi; Brush kushandiswa kwezvinhu zvishoma, zvakakodzera pamutengo wepamusoro wezvikamu zviviri zvekuputira; Maitiro ekubhurasha ane zvakakwirira zvinodiwa kune anoshanda, uye madhirowa uye zvinodiwa pakupfekedza zvinofanirwa kunyatsogayiwa kusati kwavakwa, uye mazita ezvikamu zvePCBA anogona kuzivikanwa, uye zviratidzo zvinobata maziso zvinofanirwa kunamirwa kune zvikamu zvisingabvumirwe. kuvharwa. Mushandi haabvumirwi kubata plug-in yakadhindwa nemaoko chero nguva kudzivirira kusvibiswa;
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b. Dip neruoko
Hand dip coating method
Iyo dip coating process inopa yakanakisa coating mhedzisiro, ichibvumira yunifomu, inoenderera coating kuiswa kune chero chikamu chePCBA. Dip coating process haina kukodzera zvikamu zvePCBA zvine anogadzirika capacitors, trimmer cores, potentiometers, cup-shaped cores uye zvimwe zvisina kuvharwa zvisimbiso.
Zvikamu zvakakosha zve dip coating process:
Gadzirisa viscosity yakakodzera; Dzora kumhanya uko PCBA inosimudzwa kudzivirira mabhuru kubva pakuumbwa. Kazhinji hapana kupfuura 1 mita pasekondi kuwedzera kumhanya;
c. Kupfapfaidza
Kupfapfaidza ndiyo inonyanya kushandiswa uye inogamuchirwa nyore nzira nzira, iyo yakakamurwa muzvikamu zviviri zvinotevera:
① Kupfapfaidza nemaoko
Manual spraying system
Inokodzera mamiriro ekuti workpiece yakanyanya kuomarara uye yakaoma kuvimba neotomatiki michina yekugadzirwa kwakawanda, uye zvakare inokodzera mamiriro ekuti mutsara wechigadzirwa une marudzi mazhinji asi huwandu hudiki, uye hunogona kupfapfaidzwa. chinzvimbo chakakosha.
Kupfapfaidza nemaoko kunofanirwa kucherechedzwa: mhute yependi inosvibisa mamwe maturusi, akadai sePCB plug-ins, IC sockets, mamwe anonzwisa tsitsi uye dzimwe nzvimbo dzepasi, zvikamu izvi zvinoda kutarisisa kuvimbika kwekudzivirira kwekudzivirira. Imwe pfungwa ndeyekuti mushandisi haafanire kubata plug yakadhindwa neruoko chero nguva kudzivirira kusvibiswa kweplug yekubata kumeso.
② Kupfapfaidza otomatiki
Zvinowanzoreva kupfapfaidza otomatiki nemidziyo yekuisa yakasarudzika. Inokodzera kugadzirwa kwemazhinji, kuenderana kwakanaka, kurongeka kwepamusoro, kusvibiswa kwezvakatipoteredza kushoma. Nekuvandudzwa kweindasitiri, kuvandudzwa kwemitengo yevashandi uye zvakaomesesa zvinodiwa zvekuchengetedza kwezvakatipoteredza, otomatiki yekupfapfaidza michina iri kutsiva zvishoma nezvishoma dzimwe nzira dzekuputira.