|
|
Article: Effects of SAC alloy copper dissolution rates on PTH processes: cost and performance justify use of certain alternatives to SAC 305/405.
- Article from:
- Circuits Assembly
- Article date:
- June 1, 2007
- Author:
CopyrightCOPYRIGHT 2007 UP Media Group, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
There is no doubt any company that has transitioned to Pb-free assembly, and has attempted to rework PTH connectors using conventional equipment with either SAC 305 or 405 alloys, experienced some degree of copper dissolution. Depending on the size and complexity of the connector and PCB itself, the extent of dissolution would have ranged from either a slight loss of the barrel knee and annular ring edges to a complete loss of the pad surface, barrel knee and portions of the barrel wall on numerous barrel locations of the reworked connector.
Copper dissolution during PTH rework is not a new phenomenon. In some cases, high degrees of copper dissolution occurred ...