| panda-liu |
2007-11-04 17:54 |
吆喝一下...，呵呵。
Conclusion
According to the data obtained the newer high temperature OSP coatings performed the same as far as wetting as the OSP designed for Sn/Pb processing. The only difference seen was in the amount of discoloration observed as the boards went through the process. The older OSP coating showed more discoloration which is an indication that the OSP is not protecting the copper as well as it should for the high temperature profiles used for lead-free soldering. No dewetting or other unusual defects were seen for any of the OSP coatings. For Pb-free solder pastes the newer coating should work sufficiently. One item not checked during this evaluation is the hole fill for plated through hole components. Based on what has been observed in these tests, Pb-free solder does not spread on the OSP coated boards, the solder wets only to where the solder is touching. For hole fill, this could be problematic. Further study is needed in this area. |
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