Solder Paste yeSMT Assembly: Mhando, Kuchengeta, uye Zvikanganiso zvePrinting

Solder paste ndiyo grey texture inoita kuti pave nekukwanisa kusanganiswa pamusoro pechinhu, asi mhedzisiro yekugadzira inoenderana ne alloy chaiyo, flux chemistry, storage control, uye stencil-printing discipline. Gwaro iri rinotsanangura kuti solder paste inokanganisa sei SMT good, chii chinoshanduka pakati pesarudzo dzisina lead ne lead, maitirwo ekuichengeta nemazvo, uye kuti ndeapi matambudziko anofanira kudzivirira vasati vadzoreredza mvura.

1. Chii chinogadzirwa ne solder paste?

Solder paste inogadzirwa nezvinhu zviviri: upfu hwe microscopic solder-alloy uye flux medium inoisunga kuita paste. Upfu uhu hunogadzira majoini panguva yekudzokorodza, nepo flux ichibvisa oxide kubva pasimbi, ichibatsira solder yakanyungudutswa kunyorovesa mapedhi, uye ichibata zvikamu panzvimbo yayo kwenguva pfupi isati yadziiswa. Nehuremu, paste iyi inonyanya kuva upfu; kana tichitarisa huwandu, flux yacho inenge iri chidimbu chine revo, ndosaka dhipoziti rakadhindwa richioneka richidzikira kana flux yatsva muovheni.

Upfu hunorongwa zvichienderana nehukuru hwezvimedu, zvichinzi "Type" number: Type 3 inokodzera general assembly, nepo Type 4, Type 5 uye finer zvichidikanwa pazvikamu zvidiki uye zvakamanikana apo paste inofanira kusvinwa nepakati pemaburi madiki estencil. Finer powder inodhura zvakanyanya uye inonyanya kubatwa, saka grade yacho inoenderana nechinhu chidiki pane bhodhi. Kana musiyano uripo pakati pepaste ne plain flux usina kujeka, kuenzanisa uku kwe solder paste vs solder flux kunoibvisa.

2. Paste isina mutobvu kana mutobvu (SAC305 vs Sn63/Pb37)

Paste isina mutobvu (kazhinji SAC305) inonyunguduka pa217-227°C, nepo paste ine mutobvu (Sn63/Pb37) inonyunguduka pa183°C uye inoyerera zviri nyore. Sarudzo inowanzo kukonzerwa nekutevedzera mitemo: zvigadzirwa zvinotengeswa mumisika yeRoHS zvinoda nzira yekusonesa isina mutobvu kunze kwekunge zvichikodzera kuregererwa, nepo paste ine mutobvu ichiramba iripo mune mamwe mashandisirwo akasarudzika uye ekare.

Kunyunguduka kwakanyanya kwemafuta asina lead kunoreva kuti zvinhu zvinopisa zvakanyanya uye kuti zvinhu zvinofamba zvakanaka, saka kudzora mashandiro kunonyanya kukosha. Kune zvigadzirwa zvakawanda zvemabhizinesi nhasi, kusava ne lead ndiyo nzira yekutanga zvinhu pasina lead kunze kwekunge paine chikonzero chaicho.

3. Hapana mvura inoyerera yakachena, inonyunguduka mumvura, kana kuti inoyerera nerosin: ndeipi yekusarudza

Sarudza mvura isina kuchena kuti iunganidzwe, inonyungudika mumvura kana uchida kunyoroveswa zvakanyanya uye ichasuka bhodhi, uye rosin flux yekusonesa nemaoko uye kugadzirisa patsva. Mvura isina kuchena inosiya tsvina diki, isina njodzi iyo inowanzo shambwa uye ndiyo inowanzo shandiswa pakugadzirwa kwemazuva ano. Mvura inonyungudika inonyorovesa zvakanaka asi inosiya tsvina inoparadza inofanira kugezwa zvachose. Rosin-based flux (RMA) ndiyo kemikari yekare - inowanikwa mumhando dzakasiyana dze lead ne lead - uye tsvina yayo inowanzo tsvairwa kuti ipedzwe zvakanaka.

Kuyerera kwakakodzera kunoenderana nekuti bhodhi rinocheneswa sei, kuti circuit yacho inonzwa sei kana yasara, uye kuti kirasi yekuvimbika ndeyechokwadi. Kana usina chokwadi, hapana kuchena ndiyo sarudzo yakachengeteka, ine kuchenesa kunowedzerwa kana chitarisiko kana kuvimbika kwakanyanya kuchidikanwa.

4. Mashandisirwo ekushandisa solder paste nestencil uye reflow

Kuti ushandise solder paste, iprinda pamapedhi uchishandisa stencil, isa zvikamu mu wet paste, wobva wapisa bhodhi rese muovheni kuti joint yega yega iite kamwe chete - isa woisa pakutanga, wozopedzisira wapisa. Izvi zvinopesana ne wire soldering, kwaunodziisa joint yega yega. Mukugadzira, kutevedzana kunofamba pamutsetse weSMT assembly wakarongeka :

• Kudhinda mastencil. Simbi yakachekwa nelaser SMT stencil inogara pabhodhi uye simba rekudzvanya rinonamira nepakati pemaburi papedhi rega rega. Saizi yemusuwo uye ukobvu hwestencil zvinogadzirisa vhoriyamu yekusonesa - chimwe chezvinhu zvakakosha - zvinodzorwa nekungwarira dhizaini yekuvhura stencil.
• Kuiswa. Muchina wekusarudza-uye-kuisa unoisa chikamu chimwe nechimwe pamapedhi azvo akafukidzwa nepaste; paste inonamira inovabata kusvika yadzoka.
• Kudzokazve. Bhodhi rinopfuura nepaprofile inodzorwa - kupisa, kunyikwa, kukwira pamusoro penzvimbo yekunyunguduka kwealloy, wozotonhodza. kudzokorora purofiti yekusonesa inoita kuti flux ishande uye kusimba kwenzvimbo kunokwevera chikamu chimwe nechimwe kuti chienderane.
• Kuongorora. AOI inotarisa majoini uye nzvimbo yawo mushure mekubudazve kweropa, uye X-ray inoongorora majoini akavanzwa pasi peBGAs.

Kune ma prototypes, vagadziri vanoshandisa stencil yemaoko ine hot plate kana hot-air station; nheyo dzacho dzakafanana, dzakaderedzwa. Chikanganiso chinowanzoitika kune vanotanga ipaste yakawandisa, iyo inokonzera mabhiriji, saka tsvaga dhayi rakatetepa, rakaringana rinoenderana nepedhi.

5. Maitiro ekuchengetedza paste yesolder uye nguva yayo yekushanda

Chengeta paste yakasungirirwa yakavharwa mufiriji panosvika 2-10°C, uko nguva yekushanda kwayo inowanzova mwedzi 6-12; patembiricha yemumba paste isina kuvhurwa inogara mavhiki chete. Dziisa chirongo chakavharwa patembiricha yemumba (kazhinji maawa 4-6) usati wavhura, kuitira kuti mvura isasasvibise paste yacho uye isapararire kana kuti isabuda.

Mimwe mitemo mishoma inoita kuti ive neutano hwakanaka: remekedza nguva yaunovhura uye isina basa, sezvo paste yakadhindwa ine nguva shoma yekushanda pastencil isati yaoma; usamboiisa mufiriji zvakare; usamboisanganisa yekare neitsva; uye rasa paste yapera pane kuiisa pangozi. Paste yesolder chinhu chinoora, uye kusaibata zvakanaka ndicho chikonzero chakavanzika chekusashanda zvakanaka, saka itore seyakashandiswa.

6. Kukanganisika kwepaste yesolder: kubatanidza, kugadzira matombo eguva, uye maburi asina chinhu

Zvikanganiso zvakawanda zvinosanganisirwa ne solder-paste - kubatanidza, kutema matombo, kudzima, kusakwana kwe solder, uye mabhora e solder - dzokera kumashure kusvika pahuwandu hwe paste, alignment, kana reflow profile. Kuziva chikonzero kunokubatsira kudzivirira kugadzirisa patsva pane kuitevera:

Nyaya inowanzo shandiswa ndeyekutonga maitiro. Kunzwisisa maitiro akasiyana-siyana ezvikanganiso zveSMT zvinoitwa pakugadzira mabhodhi anodhindwa zvakanaka, uye kunyanya kugadzira makuva kune zvikonzero zvinozivikanwa uye zvinogadzirisa zvinhu.

7. Solder paste mukugadzirwa kweSMT gungano

Kupfuura ma prototypes mashoma - uye zvechokwadi kune fine-pitch kana BGA - solder paste inonyatso tarisirwa senzira inodzorwa. Panyaya yehunyanzvi, stencil yakagadzirwa yakavakirwa pa geometry yepad yebhodhi rako uye pitch yakanakisisa, paste inosarudzwa zvichienderana neRoHS yako uye zvinodiwa zvekuvimbika, uye profile yakagadzirirwa alloy yakasarudzwa, ichitsigirwa ne paste inspection, AOI, uye X-ray yemajoini akavanzwa.

Zvikanganiso zvakawanda zvine chekuita nepaste inyaya dzekugadzira - saizi dzemapedhi, nzvimbo, uye nzvimbo inoita kuti kudhinda kwakanaka kuve kwakaoma - saka kutarisa kwekugadzira pakutanga kunopa stencil neprofile mukana wakanaka wekuti majoini acheneswe kekutanga. Highleap inomhanya nenzira yakazara kuburikidza neSMT PCB assembly uye, kana mabhodhi achida, assembly yeBGA yakasarudzika ine X-ray verification. Paunokumbira mutengo weassembly, tiudze kana chigadzirwa chinofanira kunge chisina lead, chero chinodiwa chekuchenesa, uye chikamu chidiki kana pitch pabhodhi.

Tora mutengo weSMT assembly

8. Mibvunzo Inowanzo bvunzwa nezve paste yesolder

Chii chinogadzirwa ne solder paste?

Kusungirirwa kweupfu hwakatsetseka hwe solder-alloy mu flux medium. Upfu hunogadzira majoini panguva yekuyererazve; flux inochenesa simbi, inobatsira kunyorovesa, uye inochengetedza zvikamu panzvimbo.

Ndeupi musiyano uripo pakati pechipunu chisina lead nechipunu chine lead?

Paste isina mutobvu (SAC305) inonyunguduka panosvika 217-227°C uye inoenderana neRoHS; paste ine mutobvu (Sn63/Pb37) inonyunguduka zvishoma panosvika 183°C, inoyerera zviri nyore, asi inoganhurirwa pasi peRoHS.

Unoshandisa sei solder paste?

Prinda pamapedhi (nekudhinda stencil kuti uwane mhedzisiro yakanaka), isa zvinhu zvacho mupaste yakanyorova, wobva wapisa bhodhi rese muovheni kuti majoini ese aumbe panguva imwe chete. Isa woisa pakutanga, wozopedzisira wapisa.

Ko solder paste inoda kuchengetwa mufiriji here, uye inochengetwa kwenguva yakareba sei?

Ehe - chengeta yakavharwa panosvika 2-10°C, uko nguva yekushanda kwayo inowanzova mwedzi 6-12. Idziyisei patembiricha yemukamuri musati mavhura kudzivirira kutonhora.

Sei majoini angu epamusoro ari kubatana?

Kazhinji maburi akawandisa epaste kana stencil akakura zvakanyanya, dzimwe nguva nekusarongeka zvakanaka. Kuderedza saizi yeburi, kusimbisa stencil, uye kutarisa kumanikidzwa kwekudhinda zvinowanzogadzirisa dambudziko racho.

Highleap inogona kubata fine-pitch uye BGA assembly here?

Ehe. Highleap inoshandisa mapendi emhando yepamusoro, mastencil akagadzirirwa kupinza zvakasimba, mapurofayiri ekudzokorora anodzorwa, uye kuongororwa kweX-ray kwemajoini akavanzwa, pamwe nekutarisa kugona kwekugadzira pachine nguva.