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Basa re reflow welding mu SMT process

Reflow soldering ndiyo inonyanya kushandiswa pamusoro pechikamu welding nzira muSMT indasitiri.Imwe nzira yewelding ndeye wave soldering.Reflow soldering inokodzera chip zvikamu, nepo wave soldering yakakodzera pini yemagetsi zvikamu.

Reflow soldering zvakare iri reflow soldering maitiro.Nheyo yayo ndeyekudhinda kana kujejera yakaringana solder paste paPCB pad uye kunamira iyo inoenderana SMT chigamba chekugadzirisa zvikamu, wobva washandisa inopisa mhepo inopisa yekupisa yevira reflow kunyungudutsa solder paste, uye pakupedzisira kuumba yakavimbika solder joint. kuburikidza nekutonhodza.Batanidza izvo zvikamu nePCB pad kuti uite basa rekubatanidza mechaniki uye kubatanidza magetsi.Kazhinji kutaura, reflow soldering yakakamurwa kuita matanho mana: preheating, tembiricha isingaperi, kuyerera uye kutonhora.

 

1. Preheating zone

Preheating zone: ndiyo yekutanga kupisa nhanho yechigadzirwa.Chinangwa chayo ndechekukurumidza kupisa chigadzirwa pakupisa kwekamuri uye kumisa solder paste flux.Panguva imwecheteyo, ihwowo nzira yekudziya inodiwa kuti udzivise kushayikwa kwekupisa kwezvikamu zvinokonzerwa nekupisa kwekupisa kwepamusoro panguva yekunyudzwa kwetini kunotevera.Naizvozvo, pesvedzero yekukwira kwekushisa pachigadzirwa yakakosha zvikuru uye inofanirwa kudzorwa mukati mechikamu chinonzwisisika.Kana ikanyanya kukurumidza, inoburitsa kuvhundutsa kwemafuta, PCB uye zvikamu zvinokanganiswa nekushushikana kwekupisa uye kukonzera kukuvara.Panguva imwecheteyo, iyo inonyungudutsa mune solder paste inoputika nekukurumidza nekuda kwekupisa nekukurumidza, zvichikonzera kupfacha uye kuumbwa kwe solder bead.Kana ikanyanya kunonoka, solder paste solvent haizonyungudika zvizere uye inokanganisa kunaka kwewelding.

 

2. Constant tembiricha zone

Constant tembiricha zone: chinangwa chayo ndechekudzikamisa tembiricha yechinhu chimwe nechimwe paPCB uye kusvika pachibvumirano nesezvinogoneka kudzikisa mutsauko wekushisa pakati pechinhu chimwe nechimwe.Panguva ino, nguva yekudziya yechikamu chimwe nechimwe chakareba, nekuti zvidiki zvinotanga kusvika pachiyero nekuda kwekupisa kushoma, uye zvikamu zvakakura zvinoda nguva yakakwana yekubata nezvikamu zvidiki nekuda kwekupisa kukuru, uye kuve nechokwadi kuti iyo flux. mu solder paste yakanyungudika zvizere.Panguva ino, pasi pekuita kwekuyerera, iyo oxide pane padhi, solder bhora uye chikamu chepini ichabviswa.Panguva imwecheteyo, iyo inoyerera ichabvisawo kusvibiswa kwemafuta pamusoro pechikamu uye padhi, kuwedzera nzvimbo yewelding uye kudzivirira chikamu kuti chisave oxidized zvakare.Mushure meichi nhanho, zvese zvinongedzo zvinofanirwa kuchengetedza zvakafanana kana zvakafanana tembiricha, zvikasadaro kushata kunopisa kunogona kuitika nekuda kwekunyanya kupisa mutsauko.

Iyo tembiricha uye nguva yekugara tembiricha zvinoenderana nekuoma kwePCB dhizaini, mutsauko wezvikamu zvemhando uye huwandu hwezvikamu.Kazhinji inosarudzwa pakati pe120-170 ℃.Kana iyo PCB yakanyanya kuomarara, tembiricha yekugara tembiricha yenzvimbo inofanirwa kutariswa nerosin inopfavisa tembiricha sereferensi, kuitira kudzikisa nguva yewelding yereflow zone muchikamu chinotevera.Iyo inogara tembiricha nzvimbo yekambani yedu inowanzosarudzwa pa160 ℃.

 

3. Reflux nzvimbo

Chinangwa cheiyo reflow zone ndechekuita kuti solder paste inyunguduke uye kunyorovesa padhi pamusoro pechinhu kuti chive welded.

Kana iyo PCB board ichipinda munzvimbo yekuyerera, tembiricha inokwira nekukurumidza kuita kuti solder paste isvike pakunyungudika.Nzvimbo yakanyunguduka yelead solder paste SN: 63 / Pb: 37 is 183 ℃, uye inotungamira-isina solder paste SN: 96.5/ag: 3 / Cu: 0. Nzvimbo yekunyungudika ye5 i217 ℃.Muchikamu chino, iyo heater inopa kupisa kwakanyanya, uye tembiricha yevira ichaiswa kune yakakwirira kwazvo, kuitira kuti solder paste tembiricha ikwire nekukurumidza kusvika pakakwirira tembiricha.

Iyo tembiricha yepamusoro ye reflow soldering curve inowanzo tsanangurwa nenzvimbo yekunyungudika ye solder paste, PCB bhodhi uye tembiricha inodzivirira kupisa kwechikamu chacho pachacho.Iyo yepamusoro tembiricha yezvigadzirwa munzvimbo inoyerera inosiyana zvichienderana nerudzi rwesolder paste inoshandiswa.Kazhinji, tembiricha yepamusoro ye lead-isina solder paste inowanzo 230 ~ 250 ℃, uye iyo ye lead solder paste inowanzo 210 ~ 230 ℃.Kana tembiricha yepamusoro yakanyanya kuderera, zviri nyore kugadzira inotonhora welding uye kusakwana kunyorova kwemasolder joints;Kana yakanyanya kukwirisa, iyo epoxy resin type substrate uye mapurasitiki anowanzo kubikira, PCB inopupuma uye delamination, uye zvakare zvinozotungamira mukuumbwa kweakawandisa eutectic simbi makomisheni, zvichiita kuti solder joint brittle uye simba rewelding rishaye simba, zvichikanganisa mechanical properties yechigadzirwa.

Zvinofanira kusimbiswa kuti flux mu solder paste munzvimbo inoyerera inobatsira kusimudzira wetting pakati solder paste uye chikamu welding kuguma uye kuderedza tension pamusoro solder paste panguva ino, asi kukwidziridzwa kuyerera kuchaita. kudziviswa nekuda kweokisijeni yasara uye masimbi epamusoro oxides muvira reflow.

Kazhinji, yakanaka tembiricha tembiricha curve inofanirwa kusangana kuti tembiricha yepamusoro yepoindi yega yega paPCB inofanirwa kuenderana nepazvinobvira, uye musiyano haufanire kudarika gumi madhigirii.Nenzira iyi chete tinogona kuve nechokwadi chekuti zviito zvewelding zvakapedzwa zvakanaka kana chigadzirwa chapinda munzvimbo inotonhorera.

 

4. Nzvimbo yekutonhora

Chinangwa chenzvimbo yekutonhodza ndechekukurumidza kutonhorera yakanyungudutswa solder paste zvimedu uye nekukasira kugadzira majoini anopenya ane solder anononoka radian uye yakazara tin.Naizvozvo, mafekitori mazhinji anodzora nzvimbo yekutonhodza zvakanaka, nekuti inokodzera solder kuumba majoini.Kazhinji, kukurumidza kutonhora kutonhora kuchaita kuti inonoke kuti yakanyungudutswa solder paste itonhore uye bhafa, zvichikonzera kukwenya, kurodza uye kunyange maburrs eakaumbwa solder joint.Kunyanya kutonhora kutonhora kuchaita kuti hwaro hwezvinhu zvePCB pad uso ubatanidzwe mune solder paste, kuita iyo solder joint rough, isina chinhu welding uye yakasviba solder joint.Uyezve, magazini ose simbi pachikamu solder magumo achanyunguduka panguva solder akabatana chinzvimbo, zvichiguma nyoro kuramba kana murombo nomoto pachikamu solder kuguma, Zvinokanganisa nomoto unhu, saka yakanaka kutonhora mwero inokosha zvikuru solder majoini kuumba. .Kazhinji, mutengesi wepaste anokurudzira chiyero chekutonhodza chejoint ≥ 3 ℃ / s.

Chengyuan indasitiri ikambani inoshanda mukupa SMT uye PCBA yekugadzira mutsara michina.Inokupa iwe sarudzo yakakodzera kwazvo.Iyo ine makore mazhinji ekugadzira uye R & D ruzivo.Nyanzvi dzehunyanzvi dzinopa kutungamira kwekumisikidza uye mushure mekutengesa-musuo nesuo sevhisi, kuitira kuti usanetsekane kumba.


Nguva yekutumira: Kubvumbi-09-2022