We have the same component used. I share some information to u.

Our customer required void is less than 25% which be calculated with soldering area.  At the beginning , For meeting this requirement, need much solder paste , this caused solder ball problem.

Now we did some improvement, like reduce aperture of stencil(thickness is 0.18mm)  like pic shown, the void could be less than 15% , also pay attention to the reflow temperature.

 

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Suggest You need do many experiments to get best parameter of process.

 

From: TGAsia [mailto:[log in to unmask]] On Behalf Of Peng Yunjun
Sent: Tuesday, November 29, 2011 11:50 AM
To: [log in to unmask]
Subject: [TGAsia] 答复: [RMX:###] [TGAsia] 陈海燕 不在办公室。

 

各位专家，
我们IPC中说了，空洞现象正常。偏移可以25%。
也就是说我们焊接面积的覆盖率小于75%是可以接受的，那到底底线是多少50%， 或者是什么值。

sop下面带散热体的元件， 有同样的问题，如覆盖面积过大，容易有焊球！
望高手指教！！！




Peng Yunjun(Mr) 彭云军(先生)
CACC PT Department
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+86-431-84684785
13756139127

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