SMT 缺陷.pdf - 第18页
12 Countermeasure/ 对策 1. Raw material damaged: purge the batch mat erial./ 来料损坏 : 清除这批来料 . 2. Damaged during SMT process (Fixture or machine touch it) : Investigate and t ake corrective actions for nonstandard operation.…
11
Component damaged (Nicks, cracks, or
stress fractures)/ 元件损坏
Nicks, cracks, or stress fractures.
缺口，裂纹，压痕
12
Countermeasure/对策
1. Raw material damaged: purge the batch material./来料损坏: 清除这批来料.
2. Damaged during SMT process (Fixture or machine touch it) : Investigate and take
corrective actions for nonstandard operation.
在SMT流程中损坏(夹具和设备接触): 调查分析并且对不规范的操作作出矫正行动.
3. Fast cooling rate on reflow process : Control the SMA cooling rate to below 4degree
per second.
在回流过程中冷却速率过快: 控制SMA的冷却速度使斜率保持在每秒4度以下.
Typical reflow profile/ 回流曲线典例:
Preheat
stage
Soak stage
Reflow stage
Peak temp.
Cool
down
<4
o
C/s
Component damaged (Nicks, cracks, or
stress fractures)/ 元件损坏
8、焊锡太多或太少(SOLDER VOLUME FAULT)
9 焊锡量太多或太少
¾ 印刷锡膏量
¾ 回流工艺
¾ 可焊性
焊锡太多
焊锡太少
STENCIL对SMT工艺的影响
2-2、常见SMT工艺缺陷分析: