|
|
Article: Dry solder joints and assembly cleanliness: Les defines solderability and troubleshoots cleaning process problems.(Ask Les)
- Article from:
- Circuits Assembly
- Article date:
- June 1, 2003
- Author:
CopyrightCOPYRIGHT 2003 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)
|
Q: What is a "dry joint?" Why is it important that a circuit board have no dry joints?
A: To achieve a solder joint between two mating surfaces, liquid solder must wet and flow over those surfaces to form a metallurgical bond. The IPC-T-50 Terms and Definitions document defines solder wetting as "the formation of a relatively uniform, smooth, unbroken and adherent film of solder to a basis metal."
In the industry, the term dry joint refers to a condition where the solder does not wet and flow on the pads of the printed wiring board and the component terminations. Instead, the solder beads up, similar to the way water does on a freshly waxed surface. Dry ...