本書以豐富詳盡的設(shè)計(jì)缺陷案例分析為抓手，指出導(dǎo)致電子裝備質(zhì)量問題的主要因素是設(shè)計(jì)缺乏可制造性，在此基礎(chǔ)上以較大篇幅介紹PCB/PCBA可制造性設(shè)計(jì)的設(shè)計(jì)理念、設(shè)計(jì)程序和設(shè)計(jì)方法，創(chuàng)新性地將設(shè)計(jì)與工藝、工藝與工藝過程控制結(jié)合起來，以幫助電子企業(yè)的管理者、電路設(shè)計(jì)師和電子裝聯(lián)工藝師建立“設(shè)計(jì)是源頭，工藝是關(guān)鍵，物料是保障，管理是根本，理念是核心”的高可靠電子裝備電子裝聯(lián)核心理念，掌握可制造性設(shè)計(jì)程序和具體方法，并對業(yè)內(nèi)極為關(guān)注的若干現(xiàn)代電子裝聯(lián)技術(shù)問題進(jìn)行了答疑與詮釋。本書既可作為電路設(shè)計(jì)師、電子裝聯(lián)工藝師、產(chǎn)品質(zhì)量保障師、企業(yè)管理人員、電裝技師及高級(jí)技師等人員的工作指導(dǎo)手冊和培訓(xùn)教材，也可作為相關(guān)高等院校電路設(shè)計(jì)和工藝制造等專業(yè)師生的教學(xué)用書。
陳正浩：在中國電科第10研究所和中國電科從事軍用電子裝備電子裝聯(lián)技術(shù)/SMT研究半個(gè)世紀(jì)；20世紀(jì)90年代被推選為中國電子學(xué)會(huì)電子裝聯(lián)/SMT專委會(huì)委員；國家高技能人才培訓(xùn)基地授課講師；中國電子科技集團(tuán)公司工藝技術(shù)專家。
目錄
第1章總則
1.1 概述 ................................................................................................................................1
1.2 我國電子制造業(yè)面臨的困境 ..................................................................................2
1.2.1 困境之一：高端芯片的缺失 .............................................................................2
1.2.2 困境之二：DFM的嚴(yán)重缺失 ...........................................................................4
1.2.3 困境之三：不適應(yīng)先進(jìn)生產(chǎn)力發(fā)展的舊工藝管理體制 .................................6
1.2.4 困境之四：被嚴(yán)重低估了的工藝和制造價(jià)值 .................................................7
1.2.5 被扭曲了的電子裝聯(lián)標(biāo)準(zhǔn) ................................................................................8
1.3 實(shí)現(xiàn)高可靠質(zhì)量目標(biāo)的因素 ..................................................................................9
1.4 中國制造需要“大國工藝” ..................................................................................10
1.4.1 精湛的工匠技藝源自先進(jìn)的工藝技術(shù) ...........................................................10
1.4.2 電子裝聯(lián)技術(shù)的重要性 ...................................................................................11
1.5 先進(jìn)制造技術(shù) ...........................................................................................................12
1.5.1 什么是先進(jìn)制造技術(shù) .......................................................................................12
1.5.2 電氣互連先進(jìn)制造技術(shù) ...................................................................................12
1.5.3 新型元器件與高密度組裝技術(shù) .......................................................................12
1.5.4 微組裝先進(jìn)制造技術(shù) .......................................................................................13
1.5.5 可制造性設(shè)計(jì)是實(shí)現(xiàn)先進(jìn)制造技術(shù)的前提和技術(shù)支撐 ...............................13
1.6 可制造性設(shè)計(jì)理念的拓展.....................................................................................14
1.7 結(jié)束語 .........................................................................................................................15
第2章PCB/PCBA設(shè)計(jì)缺陷案例分析
2.1 焊盤尺寸設(shè)計(jì)缺陷 ..................................................................................................16
2.1.1 片式元器件焊盤設(shè)計(jì)缺陷 ...............................................................................17
2.1.2 片式元器件錯(cuò)誤的“常見病、多發(fā)病” ........................................................20
2.1.3 焊盤兩端不對稱，走線不規(guī)范 .......................................................................21
2.1.4 焊盤寬度及相互間距離不均勻 .......................................................................23
2.1.5 IC焊盤寬度間距過大 ......................................................................................23
2.1.6 QFN焊盤設(shè)計(jì)缺陷 ..........................................................................................24
2.1.7 安裝孔金屬化，焊盤設(shè)計(jì)不合理 ...................................................................25
2.1.8 共用焊盤問題導(dǎo)致的缺陷 ...............................................................................26
2.1.9 熱焊盤設(shè)計(jì)不合理 ...........................................................................................26
2.1.10 片式電容器焊盤長度設(shè)計(jì)不合理 .................................................................28
2.1.11 其他焊盤設(shè)計(jì)缺陷 .........................................................................................28
2.2 絲網(wǎng)和阻焊膜設(shè)計(jì)不良 .........................................................................................30
2.2.1 絲網(wǎng)設(shè)計(jì)不良 ...................................................................................................30
2.2.2 阻焊膜設(shè)計(jì)不良 ...............................................................................................33
2.3 元器件布局不合理 ..................................................................................................35
2.3.1 布局設(shè)計(jì)不良 ...................................................................................................35
2.3.2 應(yīng)用波峰焊接工藝時(shí)，元器件布局沒有采取克服“陰影效應(yīng)”措施 .......37
2.3.3 元器件的排布不符合工藝要求 .......................................................................37
2.3.4 安放在PCB焊接面的QFP和SOIP沒有設(shè)計(jì)成“菱形”和設(shè)計(jì)導(dǎo)流盤 ........37
2.3.5 雙面組裝PCBA焊接面元器件焊盤或本體邊緣與插件零件邊緣距離過小 ..............38
2.3.6 元器件布放不符合自動(dòng)化生產(chǎn)要求 ...............................................................38
2.3.7 元器件布放位置距緊固件太近的設(shè)計(jì)缺陷 ...................................................39
2.3.8 波峰焊應(yīng)用中的布局設(shè)計(jì)缺陷 .......................................................................40
2.3.9 再流焊應(yīng)用中的布局設(shè)計(jì)缺陷 .......................................................................42
2.3.10 PCB布局混亂，嚴(yán)重影響焊接可靠性 ........................................................42
2.4 拼板設(shè)計(jì)不正確 .......................................................................................................44
2.5 PCB材料與尺寸不合適........................................................................................46
2.5.1 翹曲、扭曲 .......................................................................................................46
2.5.2 PCB材質(zhì)選用不當(dāng)，制作質(zhì)量低劣 ..............................................................48
2.6 BGA的常見設(shè)計(jì)問題 ...........................................................................................49
2.7 _通孔插裝中元器件引線直徑與金屬化孔孔徑和焊盤的不匹配 ................51
2.8 “飛線”問題 ..............................................................................................................54
2.9 PCB缺少工藝邊或工藝邊設(shè)計(jì)不合理 ............................................................54
2.10 插裝元器件安裝設(shè)計(jì)不良 ...............................................................................59
2.11 導(dǎo)通孔設(shè)計(jì)不良 ..................................................................................................61
2.11.1 導(dǎo)通孔設(shè)計(jì)在焊盤上 .....................................................................................61
2.11.2 導(dǎo)通孔與焊盤或元器件距離過小 .................................................................63
2.11.3 導(dǎo)通孔在屏蔽罩位置 .....................................................................................67
2.11.4 導(dǎo)通孔尺寸過大 .............................................................................................67
2.11.5 導(dǎo)通孔在元器件底部 .....................................................................................68
2.12 電連接器接觸偶與金屬化孔間隙比 ...............................................................69
2.13 PCB缺少定位孔，定位孔位置不正確 .......................................................70
2.14 焊盤與導(dǎo)線的連接 ...............................................................................................71
2.15 PCB基準(zhǔn)識(shí)別點(diǎn)缺失、設(shè)計(jì)不規(guī)范 ...........................................................72
2.16 元器件裝配設(shè)計(jì)不良 ........................................................................................74
2.17 設(shè)計(jì)缺陷所造成的焊接缺陷 .............................................................................95
2.17.1 插裝設(shè)計(jì)缺陷所造成的焊接缺陷 .................................................................95
2.17.2 貼裝 .................................................................................................................97
2.18 大面積接地和大面積PCB應(yīng)用設(shè)計(jì)缺陷 ...................................................99
2.19 工藝設(shè)計(jì)錯(cuò)誤 ......................................................................................................100
2.20 鍍金引線/焊端直接進(jìn)行錫焊的缺陷案例分析 ......................................101
2.21 多種設(shè)計(jì)缺陷 ......................................................................................................101
2.22 _因設(shè)計(jì)缺陷、物流控制失控和焊接溫度不符合規(guī)定要求引起的焊接故障 ................................................................................................................102
2.22.1 虛焊與冷焊 ...................................................................................................102
2.22.2 金屬化孔透錫率不符合要求 .......................................................................104
2.23 設(shè)計(jì)缺陷對元器件返修返工的影響 .............................................................105
2.24 設(shè)計(jì)缺陷對檢驗(yàn)檢測的影響 ...........................................................................106
2.25 設(shè)計(jì)缺陷對清洗的影響 ....................................................................................106
2.26 印制電路板組件的反變形安裝 ......................................................................106
2.27 潮濕敏感元器件（MSD）損壞 .....................................................................110
2.28 靜電敏感元器件使用上的錯(cuò)誤 .......................................................................111
2.29 返工返修（電裝整修，二次焊接） ................................................................112
2.30 電子產(chǎn)品電路設(shè)計(jì)及制造缺陷實(shí)例 .............................................................113
第3章現(xiàn)代電子裝聯(lián)核心理念及發(fā)展趨勢
3.1 現(xiàn)代電子裝聯(lián)核心理念 .......................................................................................117
3.1.1 電子裝聯(lián)技術(shù)與產(chǎn)品質(zhì)量的關(guān)系 .................................................................117
3.1.2 應(yīng)用DFX實(shí)施軍品可靠性設(shè)計(jì) ...................................................................117
3.1.3 基本概念 .........................................................................................................119
3.1.4 現(xiàn)代電子裝聯(lián)核心理念 .................................................................................122
3.2 電路設(shè)計(jì)現(xiàn)狀 .........................................................................................................126
3.2.1 引言 .................................................................................................................126
3.2.2 概述 .................................................................................................................126
3.2.3 電路設(shè)計(jì)功能的逐漸弱化 .............................................................................127
3.3 電子裝聯(lián)技術(shù)的迅速發(fā)展...................................................................................129
3.3.1 電子裝聯(lián)工程的基本概念 .............................................................................129
3.3.2 電子裝聯(lián)元器件的高速發(fā)展 .........................................................................132
3.3.3 可制造性分析軟件的應(yīng)用 .............................................................................134
3.3.4 國內(nèi)電子研制生產(chǎn)企業(yè)可制造性分析軟件應(yīng)用嚴(yán)重滯后原因分析 .........149
3.3.5 構(gòu)建DFM平臺(tái) ..............................................................................................152
3.3.6 可制造性分析與可制造性設(shè)計(jì) .....................................................................153
3.4 板級(jí)電路組裝技術(shù)的發(fā)展趨勢 .........................................................................154
3.4.1 元器件級(jí) .........................................................................................................154
3.4.2 板級(jí)電路模塊 .................................................................................................154
3.4.3 post-SMT .......................................................................................................155
3.4.4 堆疊裝配技術(shù) .................................................................................................157
3.4.5 高密度組裝中的“微焊接”工藝設(shè)計(jì) ........................................................159
3.4.6 電子產(chǎn)品高密度小型化設(shè)計(jì) .........................................................................159
3.5 微波組件基本概念及應(yīng)用技術(shù)標(biāo)準(zhǔn)現(xiàn)狀 .......................................................161
3.5.1 微波組件基本概念 .........................................................................................161
3.5.2 微波電路應(yīng)用標(biāo)準(zhǔn)現(xiàn)狀 .................................................................................162
3.6 微組裝技術(shù)基本概念及標(biāo)準(zhǔn)應(yīng)用現(xiàn)狀 ............................................................164
3.6.1 微組裝技術(shù)的特征 .........................................................................................165
3.6.2 微組裝技術(shù)的定義及關(guān)鍵點(diǎn) .........................................................................165
3.6.3 微組裝技術(shù)應(yīng)用標(biāo)準(zhǔn)現(xiàn)狀 .............................................................................166
3.6.4 微組裝結(jié)構(gòu) .....................................................................................................168
3.6.5 微波組件微組裝技術(shù)的應(yīng)用 .........................................................................172
3.7 整機(jī)級(jí)先進(jìn)制造技術(shù) ............................................................................................175
3.7.1 3D線扎設(shè)計(jì) ...................................................................................................175
3.7.2 立體建模的條件 .............................................................................................176
3.7.3 存在問題 .........................................................................................................176
3.7.4 3D布線的核心 ...............................................................................................177
3.7.5 整機(jī)/系統(tǒng)級(jí)“無線纜”連接技術(shù) ..........................................................177
3.7.6 剛-撓基板連接技術(shù) .....................................................................................178
3.7.7 背板連接技術(shù) .................................................................................................179
3.7.8 機(jī)架安裝 .........................................................................................................179
3.7.9 整機(jī)3D CAPP集成設(shè)計(jì)技術(shù) .......................................................................180
3.7.10 電子產(chǎn)品虛擬裝配技術(shù) ...............................................................................182
第4章電路可制造性設(shè)計(jì)基礎(chǔ)
4.1 概述 ............................................................................................................................184
4.1.1 電子產(chǎn)品電裝生產(chǎn)質(zhì)量問題的主要成因 .....................................................184
4.1.2 電路設(shè)計(jì)錯(cuò)誤或缺乏可制造性給制造帶來了什么 .....................................185
4.1.3 不使用DFM可能面臨高成本與高風(fēng)險(xiǎn)的巨大挑戰(zhàn) ..................................186
4.1.4 可制造性設(shè)計(jì)的嚴(yán)重缺失是導(dǎo)致國內(nèi)外電子產(chǎn)品質(zhì)量差別的核心
要素之一 ........................................................................................................186
4.1.5 實(shí)施DFM提高核心競爭力 ..........................................................................187
4.1.6 在設(shè)計(jì)初期進(jìn)行DFM ...................................................................................187
4.1.7 DFM是面向產(chǎn)品生命周期各環(huán)節(jié)設(shè)計(jì)的關(guān)鍵 ..........................................187
4.1.8 DFM不是單純的一項(xiàng)技術(shù)，它是一種思想，一個(gè)先進(jìn)的理念 ..............188
4.1.9 引入DFM來提高利潤和產(chǎn)量 ......................................................................189
4.1.10 執(zhí)行IPC、MIL或GJB、GB及行業(yè)標(biāo)準(zhǔn)的前提 ....................................189
4.1.11 缺乏DFM到處存在 ....................................................................................189
4.1.12 對設(shè)計(jì)缺陷的錯(cuò)誤認(rèn)識(shí) ...............................................................................191
4.1.13 產(chǎn)品的質(zhì)量和可靠性是設(shè)計(jì)出來的 ...........................................................192
4.2 電路可制造性設(shè)計(jì)是嶄新的概念 .....................................................................192
4.2.1 電路可制造性設(shè)計(jì)是一個(gè)嶄新的概念 .........................................................192
4.2.2 可制造性設(shè)計(jì)應(yīng)用的廣泛性 .........................................................................192
4.3 概述 ............................................................................................................................193
4.3.1 可制造性設(shè)計(jì)主要解決什么問題 .................................................................193
4.3.2 電路、結(jié)構(gòu)和工藝三者之間的關(guān)系 .............................................................194
4.4 電路可制造性設(shè)計(jì)基本文件 ..............................................................................194
4.4.1 電子裝聯(lián)用基本電路設(shè)計(jì)文件 .....................................................................194
4.4.2 電子裝聯(lián)常用標(biāo)準(zhǔn) .........................................................................................195
4.4.3 企業(yè)技術(shù)標(biāo)準(zhǔn)（典型工藝規(guī)范） ...................................................................204
4.4.4 電子裝聯(lián)常用產(chǎn)品工藝文件 .........................................................................205
4.5 可制造性設(shè)計(jì)（DFM）的基本理念 ..............................................................206
4.5.1 可制造性設(shè)計(jì)與設(shè)計(jì)工藝性或可生產(chǎn)性是一致的 .....................................206
4.5.2 DFM的誕生 ...................................................................................................207
4.5.3 DFM的定義 ...................................................................................................208
4.5.4 DFM基本工作目標(biāo) .......................................................................................208
4.5.5 DFM的職責(zé) ..................................................................................................209
4.5.6 DFM的相關(guān)活動(dòng) ..........................................................................................210
4.5.7 DFM主要活動(dòng)與原理 ...................................................................................210
4.5.8 DFM 團(tuán)隊(duì)與主要職責(zé) ...................................................................................210
4.5.9 支持 DFM 工作的工具技能 ..........................................................................210
4.5.10 DFM系統(tǒng)的主要元素 .................................................................................211
4.5.11 DFM的涵蓋面及定義 .................................................................................211
4.5.12 SMT領(lǐng)域的DFM ........................................................................................211
4.5.13 電路可制造性設(shè)計(jì)的基本理念及意義 .......................................................212
4.5.14 應(yīng)用先進(jìn)電子裝聯(lián)技術(shù)的電路可制造性設(shè)計(jì) ...........................................213
4.6 關(guān)鍵在于理念的更新 ............................................................................................215
第5章PCB/PCBA可制造性設(shè)計(jì)（DFM）
5.1 概述 ............................................................................................................................216
5.2 PCBA設(shè)計(jì)缺陷的影響 ......................................................................................217
5.3 印制電路板組件DFM的核心理念 .................................................................218
5.4 可制造性設(shè)計(jì)的組織保證措施 .........................................................................219
5.5 可制造性設(shè)計(jì)實(shí)施方案 .......................................................................................219
5.6 電路設(shè)計(jì)文件可制造性審核（工藝性審核） ................................................220
5.6.1 電路設(shè)計(jì)文件工藝性審查的形式 .................................................................220
5.6.2 電路設(shè)計(jì)文件工藝性審查（以PCBA為例） ..............................................221
5.6.3 電裝工藝設(shè)計(jì)原則與依據(jù) .............................................................................227
5.6.4 工藝性審查存在的問題 .................................................................................228
5.7 印制電路組件可制造性設(shè)計(jì)（DFM）基本概念 .......................................228
5.7.1 印制電路板可制造性設(shè)計(jì) .............................................................................228
5.7.2 印制電路板可制造性設(shè)計(jì)目的 .....................................................................228
5.7.3 印制電路板可制造性設(shè)計(jì)范圍 .....................................................................229
5.7.4 印制電路板可制造性設(shè)計(jì)的重點(diǎn) .................................................................229
5.7.5 印制電路板可制造性設(shè)計(jì)內(nèi)容 .....................................................................229
5.7.6 可制造性設(shè)計(jì)程序解析 .................................................................................229
5.7.7 PCBA組裝方式?jīng)Q定焊接工藝流程 .............................................................231
5.7.8 印制電路板電路設(shè)計(jì) .....................................................................................239
5.8 確保PCBA可制造性設(shè)計(jì)實(shí)施的物料要素 .................................................243
5.8.1 總則 .................................................................................................................243
5.8.2 高可靠印制電路板的可接受條件 .................................................................244
5.8.3 高可靠電子裝備電子元器件選用要求 .........................................................248
第6章PCB元器件布局設(shè)計(jì)及焊盤設(shè)計(jì)
6.1 表面組裝技術(shù)元器件布局設(shè)計(jì)及片式元器件焊盤設(shè)計(jì) .................................254
6.1.1 表面貼裝元器件的焊接可靠性 .....................................................................254
6.1.2 SMT印制電路板電路設(shè)計(jì)一般要求 ..........................................................255
6.1.3 SMT工藝對元器件布局設(shè)計(jì)的要求 ..........................................................257
6.1.4 采用再流焊接焊工藝的元器件焊盤設(shè)計(jì) .....................................................261
6.1.5 再流焊工藝導(dǎo)通孔設(shè)計(jì) .................................................................................373
6.2 波峰焊工藝元器件布局設(shè)計(jì)及焊盤圖形設(shè)計(jì) ..............................................374
6.2.1 采用傳統(tǒng)波峰焊工藝的元器件布局設(shè)計(jì) ...................................................374
6.2.2 采用傳統(tǒng)波峰焊工藝的元器件焊盤設(shè)計(jì) .....................................................380
第７章通用設(shè)計(jì)技術(shù)
7.1 通用設(shè)計(jì)...................................................................................................................385
7.1.1 焊盤形狀設(shè)計(jì) .................................................................................................385
7.1.2 焊盤與印制電路板的距離 .............................................................................386
7.1.3 焊盤的開口 .....................................................................................................386
7.1.4 相鄰焊盤設(shè)計(jì) .................................................................................................386
7.1.5 大型元器件焊盤設(shè)計(jì) .....................................................................................386
7.1.6 大導(dǎo)電面積設(shè)計(jì) .............................................................................................386
7.1.7 采用傳統(tǒng)波峰焊工藝時(shí)孔的設(shè)計(jì)規(guī)則 .........................................................386
7.1.8 焊盤設(shè)計(jì) .........................................................................................................388
7.1.9 焊盤與孔的關(guān)系 .............................................................................................389
7.1.10 導(dǎo)通孔與焊盤的連接設(shè)計(jì) ...........................................................................390
7.1.11 元器件孔距設(shè)計(jì) ...........................................................................................395
7.1.12 環(huán)寬要求 .......................................................................................................395
7.1.13 導(dǎo)體層的隔熱設(shè)計(jì) .......................................................................................396
7.1.14 THT圖形設(shè)計(jì) ..............................................................................................397
7.1.15 焊盤和印制導(dǎo)線的連接 ...............................................................................398
7.1.16 雙列直插式（DIP）集成電路焊盤設(shè)計(jì) ....................................................401
7.1.17 元器件的安裝間距 .......................................................................................403
7.1.18 布線設(shè)計(jì) .......................................................................................................415
7.1.19 模板設(shè)計(jì) .......................................................................................................428
7.2 設(shè)備對設(shè)計(jì)的要求 ................................................................................................441
7.2.1 印制電路板外形、尺寸設(shè)計(jì) .........................................................................442
7.2.2 印制電路板定位孔的設(shè)計(jì)要求 .....................................................................444
7.2.3 印制電路板夾持邊設(shè)計(jì) .................................................................................446
7.2.4 光學(xué)定位基準(zhǔn)標(biāo)志（Mark）設(shè)計(jì) ................................................................446
7.2.5 局部基準(zhǔn)標(biāo)志 .................................................................................................449
7.2.6 拼板設(shè)計(jì) .........................................................................................................450
7.2.7 選擇元器件封裝及包裝形式 .........................................................................454
7.3 阻焊、絲網(wǎng)的設(shè)計(jì) ................................................................................................454
7.3.1 阻焊膜設(shè)計(jì) .....................................................................................................454
7.3.2 絲網(wǎng)圖形設(shè)計(jì) .................................................................................................457
7.4 印制電路板組件導(dǎo)熱和散熱設(shè)計(jì) .....................................................................458
7.4.1 概述 ................................................................................................................458
7.4.2 印制電路板導(dǎo)熱和散熱設(shè)計(jì)工藝性要求 .....................................................459
7.4.3 元器件導(dǎo)熱和散熱設(shè)計(jì)要求 .........................................................................459
7.4.4 元器件導(dǎo)熱和散熱設(shè)計(jì)的主要填充材料和使用 .........................................460
7.4.5 印制電路板散熱設(shè)計(jì)的內(nèi)容和要求 .............................................................464
7.5 印制電路板制圖的基本要素 ..............................................................................470
7.5.1 印制電路板的表面鍍涂 .................................................................................470
7.5.2 印制電路板的標(biāo)記 .........................................................................................471
7.5.3 印制電路板圖樣的繪制 .................................................................................472
第8章通孔插裝元器件焊接工藝選擇
8.1 選擇性波峰焊接是PCBA焊接工藝流程的必然選擇 ..............................483
8.2 選擇性波峰焊接對比手工焊接 .........................................................................484
8.3 選擇性波峰焊接對比通孔回流焊接（PHR） ......................................487
8.3.1 通孔回流焊接工藝的優(yōu)點(diǎn) .............................................................................488
8.3.2 通孔回流焊接工藝的缺點(diǎn) .............................................................................488
8.3.3 通孔回流焊接工藝的適用條件（例） ...........................................................491
8.3.4 結(jié)束語 .............................................................................................................492
8.4 選擇性波峰焊接對比傳統(tǒng)波峰焊接 ................................................................493
8.4.1 雙面混裝焊接工藝比較 .................................................................................493
8.4.2 避免了傳統(tǒng)波峰焊接元器件布局的局限性 ...............................................496
8.4.3 使用帶有治具的傳統(tǒng)波峰焊接工藝 .............................................................500
8.4.4 選用選擇性波峰焊的優(yōu)越性 .........................................................................503
8.4.5 結(jié)束語 .............................................................................................................506
8.5 焊接質(zhì)量要求 .........................................................................................................507
8.5.1 焊接潤濕角 .....................................................................................................507
8.5.2 良好的焊點(diǎn)要素 .............................................................................................511
8.5.3 通孔插裝元器件手工焊與選擇性波峰焊質(zhì)量比較 .....................................515
8.6 選擇性波峰焊導(dǎo)流盤的設(shè)置 ..............................................................................518
8.6.1 傳統(tǒng)雙波峰焊原理 .........................................................................................518
8.6.2 傳統(tǒng)的雙波峰焊時(shí)DIP元器件的焊盤排列走向、橋連產(chǎn)生的原因及
導(dǎo)流盤的設(shè)置 ................................................................................................518
8.6.3 橋連現(xiàn)象及其產(chǎn)生的原因 .............................................................................520
8.7 高密度高可靠PCBA焊接工藝流程選擇 .....................................................521
8.8 選擇性波峰焊對PCB/PCBA設(shè)計(jì)的要求...................................................522
8.8.1 PCB設(shè)計(jì)一般要求 ........................................................................................522
8.8.2 選擇性波峰焊PCB設(shè)計(jì)特殊要求 ...............................................................525
8.8.3 防止橋連工藝 .................................................................................................528
8.9 選擇性波峰焊的局限性 .......................................................................................530
8.10 與波峰焊相關(guān)的禁限用工藝 .........................................................................531
第9章PCBA元器件可組裝性設(shè)計(jì)（DFA）
9.1 通孔插裝元器件穿孔安裝...................................................................................532
9.1.1 一般要求 .........................................................................................................532
9.1.2 通孔插裝元器件安裝詳細(xì)要求 .....................................................................535
9.2 表面安裝...................................................................................................................563
9.2.1 有引線的表面安裝 .........................................................................................563
9.2.2 無引線的表面安裝 .........................................................................................564
9.2.3 GJB 3243、QJ 3086、QJ 3173A和QJ 165B規(guī)定的表面貼裝元器件
安裝要求 .........................................................................................................565
9.3 THC/THD在微波基板上的安裝焊接設(shè)計(jì) .................................................573
9.3.1 引線搭接 .........................................................................................................573
9.3.2 圓形引線搭接 .................................................................................................573
9.3.3 扁平引線搭接 .................................................................................................573
9.3.4 通孔插裝元器件引線的搭接焊接要求 .........................................................574
9.4 非返工返修PCBA的跨接線（飛線、跳線） ..............................................574
9.4.1 跨接線的定義 .................................................................................................574
9.4.2 跨接線一般使用原則 .....................................................................................575
9.4.3 特殊情況下允許使用跨接線的原則 .............................................................575
9.5 PCBA返修和返工中跨接線的處理 ................................................................576
9.5.1 增設(shè)跨接線原則 .............................................................................................576
9.5.2 跨接線所選用的導(dǎo)線的選擇 .........................................................................577
9.5.3 跨接線分類 .....................................................................................................577
9.5.4 跨接線的布線 .................................................................................................577
9.5.5 跨接線的連接 .................................................................................................579
9.5.6 THT跨接線焊接要求 ...................................................................................580
9.5.7 SMT跨接線焊接要求 ..................................................................................582
9.5.8 跨接線的黏接固定 .........................................................................................587
第10章高可靠PCBA禁限用工藝及分析
10.1 高可靠PCB/PCBA禁用設(shè)計(jì)與禁用安裝工藝 ......................................589
10.1.1 概述 ...............................................................................................................589
10.1.2 什么是禁用工藝 ...........................................................................................589
10.1.3 什么是限用工藝 ...........................................................................................590
10.1.4 高可靠PCB/PCBA禁用設(shè)計(jì)與禁用安裝工藝72條 ...............................590
10.1.5 高可靠電子設(shè)備禁用工藝與材料 ...............................................................592
10.1.6 高可靠電子設(shè)備限用工藝與設(shè)計(jì) ...............................................................593
10.2 _軍品PCBA軸向引線元器件通孔插裝安裝方式——不允許軸向引線元器件垂直安裝 .........................................................596
10.2.1 問題提出 .......................................................................................................596
10.2.2 軍品（3級(jí)或C級(jí)產(chǎn)品）PCBA軸向通孔插裝元器件 ...........................597
10.2.3 分析 ...............................................................................................................598
10.3 軍品（3級(jí)或C級(jí)產(chǎn)品）PCBA通孔插裝元器件要求 ..........................599
10.3.1 軸向引腳水平安裝 .......................................................................................599
10.3.2 徑向引腳水平安裝 .......................................................................................602
10.3.3 分析 ...............................................................................................................603
10.3.4 結(jié)束語 ...........................................................................................................604
10.4 3級(jí)電子產(chǎn)品PCBA片式元器件堆疊安裝分析 .....................................604
10.4.1 概述 ...............................................................................................................604
10.4.2 問題提出 .......................................................................................................605
10.4.3 軍標(biāo)對軍用PCBA“片式元器件堆疊安裝”的規(guī)定 ...............................606
10.4.4 分析 ...............................................................................................................606
10.4.5 試驗(yàn)驗(yàn)證 .......................................................................................................610
10.4.6 結(jié)束語 ...........................................................................................................610
10.5 F型封裝大功率管的安裝焊接 .......................................................................610
10.6 QJ 3117A《導(dǎo)線在印制電路板上搭接焊接》質(zhì)疑 .............................611
10.7 元器件鍍金引線/焊端除金搪錫 ..................................................................614
10.7.1 問題提出 .......................................................................................................615
10.7.2 元器件引腳/焊端未除金搪錫導(dǎo)致的金脆化案例 ...................................615
10.7.3 金脆化分析 ...................................................................................................619
10.7.4 鍍金引線/焊端的除金規(guī)定 .......................................................................621
10.7.5 無須糾結(jié)的鍍金引線/焊端除金處理 .......................................................623
10.7.6 元器件引線/焊端“除金”工藝 ...............................................................624
10.7.7 射頻電連接器焊杯除金工藝 .......................................................................627
10.7.8 低頻（多芯）電連接器焊杯除金工藝 .......................................................627
10.7.9 先進(jìn)除金搪錫設(shè)備及工藝介紹 ...................................................................632
10.7.10 鍍金PCB焊接中產(chǎn)生的金脆化案例 .......................................................637
10.7.11 鍍金引線除金的爭議 .................................................................................639
10.7.12 結(jié)束語 .........................................................................................................642
10.8 軍用PCBA通孔插裝元器件“禁止雙面焊” ............................................643
10.8.1 引言 ...............................................................................................................643
10.8.2 什么是禁限用工藝 .......................................................................................644
10.8.3 提出“禁止雙面焊”的必要性 ...................................................................644
10.8.4 基于Pro/Mechanical對透錫量的驗(yàn)證 .......................................................649
10.8.5 “禁止雙面焊”可以做到 .............................................................................655
10.8.6 影響通孔插裝元器件金屬化孔透錫率的主要因素 ...................................655
10.8.7 如何提高印制電路板金屬化孔透錫率 .......................................................657
10.8.8 實(shí)踐驗(yàn)證 ....................................................................................................664
10.8.9 結(jié)束語 ...........................................................................................................664
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