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LH,
Based on these two photos, it is likely that the spot is flux drop + solder
drop resulted from the splattering during the solder paste reflow process.
Below is the possible solutions :
1. Shield the gold finger by using the high temperature tape or other
masking plate
2. Different solder paste may produce different result. << different
composition in the sense of chemistry >>
3. Tune the profile -
a. Longer preheat or higher soak << different paste may have different
response, several experimental runs are needed >>
b. Reduce the ramp rate of temperature slope before reflow (e.g. 0.25 to
0.5 deg. C/s)
Regards,
Jackson
Technical Services Manager
Cookson Electronics - Alpha Metals
lhkang
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CN> To
Sent by: TGAsia [log in to unmask]
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Subject
31/05/2007 11:27 [TGA] 请教
Please respond to
Asia Committe
Task Group Forum
<[log in to unmask]>;
Please respond to
lhkang
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CN>
Dear all,
请教各位附件图片1和图片3金手指上的点是怎样产生的及如何来改善?谢谢!
Best regards,
LHKang
[attachment "1.bmp" deleted by Jackson Chan/AlphaMetalsHK/Cookson]
[attachment "3.bmp" deleted by Jackson Chan/AlphaMetalsHK/Cookson] a
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