SMT 缺陷.pdf - 第13页
22 Cold solder/ Cold solder/ 冷焊 冷焊 Countermeasure/ 对策 1. Peak temperature is too low or refl ow time (dwel l time) is not enough: Re-setup the profile to fulfill the paste spec or customer provided sp ec. requirement. 回流…
21
Cold solder/
Cold solder/
冷焊
冷焊
•Incomplete reflow of solder paste.
焊锡回流不完全
22
Cold solder/
Cold solder/
冷焊
冷焊
Countermeasure/ 对策
1. Peak temperature is too low or reflow time (dwell
time) is not enough: Re-setup the profile to fulfill the
paste spec or customer provided spec. requirement.
回流峰值温度太低或者回流时间不够: 重设温度曲线图.
Typical reflow profile:/ 典型的回流曲线
Preheat
stage
Soak stage
Reflow stage
Peak temp.
Cool
down
<4
o
C/s
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Time
时间
Temp.
温度
230°C
250°C
tc1 – small SMD
tc1 – medium SMD
tc3 – large SMD
20
°C
20
°C
Too Hot!
Too Cold!
Peak: 230 – 250°C
Cold solder/
Cold solder/
冷焊
冷焊