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1、Start,SMT defect / 清洗钢网 b) Replace the recycled paste with fresh one./更换新锡膏 c) Printing machine parameter adjustment./校正丝印机参数 2. Poor solderability of component or pad./元件或焊盘可焊性太低 Root cause: a) Old date component or PCB. /陈旧元件或PCB板 b) Contamination on component or PCB. /元件或焊盘受污染 Action: Purge the m
2、aterial for further disposition. /清除来料 3. Insufficient flux volume: increase flux spray rate (wave solder). 助焊剂量不足: 增加助焊剂喷射量 (波峰焊接) 4. Preheat excess: lower preheat temperature properly (wave solder). 预热过度: 适当降低预热温度 (波峰焊) 5. Chip wave or solder wave height is low : proper height (wave solder). 波峰高度过
3、低: 调整到适当高度 (波峰焊),39,Insufficient Solder/ 少锡,Insufficient solder 焊锡不足,40,Insufficient Solder/ 少锡,Countermeasure /对策 1. Stencil aperture clogging cause incomplete solder printing): Automatic or manual clean the stencil. 钢网孔堵塞导致锡膏不完全印刷: 自动或者手工清洗钢网 2. No enough solder paste volume (Paste height under LC
4、L) : Visual inspection and Cpk control. 锡膏量不足(锡膏高度在LCL以下): 目检和Cpk控制 3. Solder paste print misalignment: Fine tune printing machine 锡膏印刷偏位:校正丝印机使之最优,4. Poor solderability of component or PCB pad: 元件或PCB焊盘可焊性差 a) Optimize reflow profile.优化回流曲线 b) Exchange the poor solderability component. 更换掉低可焊性元件 5.
5、 Excess glue or glue misalignment: Fine tune screen print (wave solder). 点胶过多或点胶偏位:优化丝印参数 6. Less flux : Increase the flux spray on board before it pass wave soldering (wave solder).助焊剂不足: 增加助焊剂的喷射量,41, Solder fillet extends on to the top of the component body. 焊锡接触元件体,Excess Solder/ 多锡,42,Excess So
6、lder/ 多锡,Countermeasure /对策 1. Excess solder paste: 锡膏量过多 a). Solder paste height out of UCL: Adjust printing machine to control the paste height. 锡膏高度超出UCL: 校正丝印机控制锡膏高度 b). Nonstandard of stencil aperture opening: standardize the stencil aperture opening for different type components. 钢网开孔不标准:为不同类型
7、的元件设置相应钢网的开孔标准 2. Wave soldering/ 波峰焊接 a) Low conveyer ramp, long wave soldering time: Adjust conveyor ramp angle to 57 degree and soldering time to 35 second. 传送带角度过小, 波峰焊接时间变长: 校正传送带角度到57度, 焊接时间35秒 b) High preheat temperature to dry off the flux: According to flux spec to control the preheat tempe
8、rature, normally the PCB surface preheat temperature should be under 100oC. 高预热温度造成助焊剂过度挥发: 按照助焊剂的规格控制预热温度, 通常, PCB表面温度 一般低于100oC,43,Wrong Orientation/ Polarity 反向, 极性反,Correct Polarity/正确的极性,Wrong Polarity/ 极性反,Anode mark on on PCB.,Anode mark on tantalum capacitor body.,Correct Polarity/正确的极性,Wron
9、g Polarity/ 极性反,Cathode mark on component body.,Cathode mark on PCB.,Wrong Polarity:/极性反,44,Wrong Orientation/ Polarity 反向, 极性反,Correct direction/ 正确的方向,Wrong Orientation/反向,IC direction mark on the device body.,IC direction mark on PCB.,Wrong Orientation/ 反向: The IC is populated in inverse directio
10、n on the PCB. IC被反方向组装在线路板上,45,Countermeasure/ 对策 1. Wrong placement machine program : Check and correct the machine program. 贴片机程序错误: 检查和更正机器程序 2. Manual placement in reverse direction: 手工放置元件错误 a) Avoid manual placement components 避免手工放置元件 b) Need special inspection for the manual placement prior
11、to reflow (document control). 炉前需要特别检查那些手工放置的元件 (文件控制) 3. Disordered orientation in the tray/reel of the incoming material: 卷装或盘装来料元件的不规则放置 a) Inspect before loading it to SMT. 上料前检查来料 b) Feedback to vendor to take corrective actions. 反馈给供应商采取改善行动,Wrong Orientation/ Polarity 反向, 极性反,46,Solder Hole/
12、锡洞, Blow holes, pinholes, voids 吹孔, 针孔,空洞,47,Solder Hole/ 锡洞,Countermeasure/ 对策 1. Insufficient preheat: Reflow pro. 预热时间不足: 优化回流曲线设置. 2. Ramp up is too fast : Re-setup the reflow pro make it optimize. 升温速率太快: 重设回流曲线图使之最优化. 3. Excess flux in solder paste: properly to increase preheat time and temper
13、ature. 锡膏助焊剂含量过多: 适当增加预热时间和温度值. 4. Damp PCB: Bake the PCB before loading it to SMT. PCB受潮: SMT组装前烘烤PCB板. 5. Component feet oxidation: Bake it before SMT or require vacuum packing on incoming material.元件脚氧化: 烘烤或者来料真空包装. 6. Attached flux residue on component foot: Sort out the defect part. 元件脚有助焊剂残渣:
14、挑选出缺陷来料.,48,Solder Projections/ 锡尖,Solder projection violates assembly maximum height requirements or lead protrusion requirements. 焊锡毛刺违反组装的最大高度要求或引脚凸出要求. Solder projection violates minimum electrical clearance. 焊锡毛刺违反最小电气间隙.,49,Solder Projections/ 锡尖,Countermeasure/ 对策 1. Less flux on board : Incr
15、ease the flux spray rate on board before go through wave soldering (wave solder). 助焊剂不足: 增加助焊剂的喷射量 2. Low conveyor ramp: Raise the conveyor ramp per actual status (wave solder). 传送带角度过小: 根据实际情况校正传送带角度 3. Excess preheat temperature and time (flux dry off): Optimize wave soldering profile. (Wave solde
16、r) 预热过度（助焊剂过度挥发）: 优化波峰曲线 (波峰焊) 4. Caused by rework: Standardize operator handling and enhance visual inspection. 返修中产生: 规范员工操作加强目检.,50,a. Long lead / Short lead 脚长/脚短 b. Missing Component 元件丢失 c. Exposed Copper 露铜 d. Surface Scratched 外观划伤 Countermeasure/ 对策 Take corrective action and preventive action after investigated. 调查后采取相应的改善措施和预防措施,Others 其它,51,Thank You,End,52,1、有时候读书是一种巧妙地避开思考的方法。20.8.1520.8.15Saturd
