SMT 缺陷.pdf - 第16页

26 Solder hole/ Solder hole/ 锡洞锡洞 Countermeasure/ 对策 1. Insufficient preheat: Reflow profile optimize. 预热时间不足 : 优化回流曲线设置 . 2. Ramp up is too fast : Re-setup the reflow profile to make it optimize. 升温速率太快 : 重设回流曲线图使之最优化 …

7、焊点缺陷(SOLDER POINT DEFECT)

9 焊点处有裂纹、针孔、吹孔等现象

¾ 锡膏质量缺陷

¾ 环境恶劣

¾ 回流缺陷

裂纹

吹孔

针孔

STENCIL对SMT工艺的影响

2-2、常见SMT工艺缺陷分析:

Solder hole/

锡洞

Countermeasure/对策

1. Insufficient preheat: Reflow profile optimize. 预热时间不足: 优化回流曲线设置.

2. Ramp up is too fast : Re-setup the reflow profile to 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 temperature.

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: 挑选出缺陷来料.

Component damaged (Nicks, cracks, or

stress fractures)/ 元件损坏

Nicks, cracks, or stress fractures.

缺口，裂纹，压痕