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1、元件吃锡效果与PCB Layout关系1元件吃锡效果与PCBLayout关系進板方向GOOD1. TWO SMD TOO CLOSE2. SMT 本體易產生陰影效應8JES326S.0A3 PCB進板方向2元件吃锡效果与PCBLayout关系光學點反黑範圍太小此光學點可以不用LAYOUT8JES326S.0A3 PCB光學點太小3元件吃锡效果与PCBLayout关系光學點為土黃色, 黑色佳8JES326S.0A3 PCB光學點顏色4元件吃锡效果与PCBLayout关系8JES326S.0A3 PCB陰影效應進板方向LAYOUT請註明進板方向5元件吃锡效果与PCBLayout关系GOOD(BIG
2、 PAD)8JES326S.0A3 PCBBIG PAD6元件吃锡效果与PCBLayout关系太密易造成短路沒拖錫點LAYOUT8JES326S.0A3 PCBCONNECTER SHORT7元件吃锡效果与PCBLayout关系8JES326S.0A3 PCB正板零件容易被破壞或掉件熱氣會由貫穿孔往上衝PTH & PAD TOO CLOSE8元件吃锡效果与PCBLayout关系8JES326S.0A3 PCB加白點有助減少short缺點, 最好加一白線加白漆防焊(文字印刷)9元件吃锡效果与PCBLayout关系8JES326S.0A3 PCBPhone jack 和SMD太近且SMT comp
3、onent 太近易短路現象發生進板方向PAD & PAD TOO CLOSE10元件吃锡效果与PCBLayout关系8JES326S.0A3 PCB光學點離pad太近(BGA會打不準)光學點& PAD TOO CLOSE11元件吃锡效果与PCBLayout关系S1024B.5A18E PCB 節省工時可使用吃錫螺絲吃錫螺絲12元件吃锡效果与PCBLayout关系S1024B.5A18E PCB增加拖錫點避免短路發生 進板方向LAYOUT請註明進板方向增加拖錫點防止短路沒有作用的拖錫點增加拖錫點避免短路發生 沒有作用的拖錫點13元件吃锡效果与PCBLayout关系S1024B.5A18E PCB
4、SOLDER SIDEIC 容易短路IC 最好LAY在正板或以45LAYOUT較不易造成PIN 腳短路否則需用昂貴治具COVERIC ON SOLDER SIDE LAYOUT DIRECTION14元件吃锡效果与PCBLayout关系S1024B.5A18E PCB不要利用螺絲孔接地PAD & SCREW HOLE GROUNDING15元件吃锡效果与PCBLayout关系S1024B.5A18E PCBVIA hole 綠漆應蓋solder side避免錫珠掉在VIA HOLE造成零件問題(翹件、空焊)SOLDER MASK ON SOLDER SIDE ONLY 16元件吃锡效果与PCB
5、Layout关系S1024B.5A18E PCB以馬賽克LAYOUT方式較好(熱平衡)DUMMY PAD17元件吃锡效果与PCBLayout关系防焊防止PTH拉錫18元件吃锡效果与PCBLayout关系TOO CLOSE容易SHORTCOMPONENT TOO CLOSE19元件吃锡效果与PCBLayout关系電容容易FAILPTH 熱氣會沖上來吃錫不好銅箔太大, 散熱太快SOLDER NOT ENOUGH20元件吃锡效果与PCBLayout关系容易SHORT吃錫後外觀不良?EASY SHORT21元件吃锡效果与PCBLayout关系陰影效應22元件吃锡效果与PCBLayout关系拖錫棒避免S
6、OCKET SHORT拖錫棒進板方向LAYOUT請註明進板方向23元件吃锡效果与PCBLayout关系避免CONNECTOR SHORT假的pad 拖錫用 進板方向LAYOUT請註明進板方向拖錫棒設計方向24元件吃锡效果与PCBLayout关系進板方向Layout 沒考量進板方向, 假pad 放錯邊SOLDER DIRECTION25元件吃锡效果与PCBLayout关系此處淚滴(TEAR DROP)設計較好,狗骨頭(DOG BONS)不好DOG BONS26元件吃锡效果与PCBLayout关系不好的接地SCREW HOLE & SMD27元件吃锡效果与PCBLayout关系goodNo goo
7、dSCREW HOLE28元件吃锡效果与PCBLayout关系不好的layout吃錫易不足散熱快goodHEAT TRANSFER29元件吃锡效果与PCBLayout关系測試點layoutTEST POINT30元件吃锡效果与PCBLayout关系過Wave solder時電解質電容容易遭熱氣上沖而Fail電容易被熱氣沖壞31元件吃锡效果与PCBLayout关系BGA LAYOUT:DOG BONSBETTER THAN TEAR DROPDog bone Vs Tear drop32元件吃锡效果与PCBLayout关系背板拖錫棒拖錫進板方向33元件吃锡效果与PCBLayout关系測試點LAY
8、OUT方式TEST POINT34元件吃锡效果与PCBLayout关系WAVE SOLDER PROFILE35元件吃锡效果与PCBLayout关系Assembly36元件吃锡效果与PCBLayout关系SMT Process Flow37元件吃锡效果与PCBLayout关系SMT Process Flow38元件吃锡效果与PCBLayout关系SMT Process Flow39元件吃锡效果与PCBLayout关系SMT Process Flow40元件吃锡效果与PCBLayout关系SMT Process Flow41元件吃锡效果与PCBLayout关系Wave soldering Pro
9、file42元件吃锡效果与PCBLayout关系Machine setup and process characteristicsBoard/wave contact lengthBoard dwell time in solder wave(s)Board immersion depth in waves(s)Conveyor speedConveryor to wave orientationPreheat temperature slopeMax preheat temperatureTemperature spike at the wave(s)Solder temperature i
10、n the wave(s)Time above liquidus43元件吃锡效果与PCBLayout关系IR Reflow Solder profile44元件吃锡效果与PCBLayout关系Vapor Phase reflow solder Profile45元件吃锡效果与PCBLayout关系PreheatingTo reduce thermal shock to PWB from solder waveTo active the flux by heating it.To dry the flux which would otherwise boil during soldering,
11、causing solder balls.To prevent the board warping during soldering.46元件吃锡效果与PCBLayout关系Stencil47元件吃锡效果与PCBLayout关系Key point of Process (1)Conveyor speedBoards pollutionDwell timeSolder temperatureSolder pot contaminationType of fluxFlux contaminationFlux foamed unevenPreheater temperatureSolder wave
12、 unevenComponents contaminationBoards oxidedBoards re-runDefective fixtureFlux Blow-off (air knife) excessiveFlux not making contractBoards not seated rightFlux foamed lowFlux specific gravity48元件吃锡效果与PCBLayout关系Key point of Process (2)Incorrect flux bubble sizeImproper board handlingSolder wave tur
13、bulentFlux no longer activePallet designDefective mask materialsInternal planes (Multilayer)Large planes on solder sidePallet too hotType of coatingBoard wrappedFlux Blow-off (air knife) not onIncorrect weight placementMisregistration of maskBase material (epoxy resin)49元件吃锡效果与PCBLayout关系Defect and
14、Counterdefect Force50元件吃锡效果与PCBLayout关系Drawbridge51元件吃锡效果与PCBLayout关系Conveyor angle52元件吃锡效果与PCBLayout关系Solder joint fail Residual plating chemicals Incomplete cleaning after plating Surface contamination Surface oxidation53元件吃锡效果与PCBLayout关系SOLDER BUMPING: VOIDING1. solvents in the flux system unabl
15、e to diffuse through the molten solder during reflow2. alloy shrinkage on cooling3. joint shape - the path of escape for vapors can be difficult and lead to entrapped gases4. improper or non-optimized heating profile5. plating or solder mask related issues (outgassing, inadequate cleaning, etc.)6. t
16、ype of solder paste and powder size used54元件吃锡效果与PCBLayout关系印刷電路板方向不當尺寸設計不良未置於定位有異物或受污染受重壓寬幅不當保護層處理不當印刷電路板或零件過期及儲存不當重量分佈不當氧化破損插件面設計不良載重過多變形焊錫面設計不良多層板內電路設計不良55元件吃锡效果与PCBLayout关系印刷電路板印刷油墨不良過量印刷油墨印刷油墨未稱位抗焊印刷不良抗焊印刷不夠貼合層內有濕氣不完全蝕刻不良穿孔空洞太大環氧樹脂基材外露環氧樹脂基材問題56元件吃锡效果与PCBLayout关系零件零件方向不當零件受污染零件披覆材質不良零件散熱不良零件腳長度
17、57元件吃锡效果与PCBLayout关系貫穿孔貫穿孔/錫墊未稱位貫穿孔內沾污油墨貫穿孔印上油墨貫穿孔留有粗糙邊粗糙與零件圓徑尺寸比率不大對58元件吃锡效果与PCBLayout关系助焊劑比重失去效能未潤濕板面助焊劑受污染發泡不正常發泡太低助焊劑發泡量不正常發泡量太少發泡過量種類選擇錯誤59元件吃锡效果与PCBLayout关系輸送帶仰角夾具設計不良帶速度微振現象60元件吃锡效果与PCBLayout关系焊錫波面不正常波面有擾流現波面有擾流現象脫離錫液面太快時間液面水平高度液面溫度第二次再過焊焊液雜質過多錫渣過多過錫方向錯誤61元件吃锡效果与PCBLayout关系其他不當之插件或裝配夾具損壞夾具過熱插件位置不符預熱溫度62元件吃锡效果与PCBLayout关系63元件吃锡效果与PCBLayout关系64元件吃锡效果与PCBLayout关系
