smt缺陷分析和防范办法smtdefectcountermeasurerevised简体中文.pptVIP

* * 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. * * Solder Projections/锡尖 Countermeasure 1. Less flux on board : Increase 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 solder) 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. * * No Solder/ 无锡 No solder to the land or termination where solder is required. 　焊点无锡 * * No Solder/ 无锡 Countermeasure/ 对策 1. Missing printing/ 漏印 Root cause: a) Stencil aperture was jammed./ 钢网堵孔 b) High viscosity of solder paste./ 锡膏粘性过高 Action: a) Clean stencil;/ 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 material 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). 波峰高度过低: 调整到适当高度 (波峰焊) * * Insufficient Solder/少锡 Insufficient solder 焊锡不足 * * Insufficient Solder/少锡 Countermeasure /对策 1. Stencil aperture clogging cause incomplete solder printing): Automatic or manual clean the ste