Surface Mount Solder Joint Issues Impacting Avionic Integrity
Abstract
This paper addresses some issues impacting surface mount solder joint life. Solder joint life expectancy depends on the level of stress experienced and the number of cycles of stress. Stress levels in the solder joint or surface mount fillet are related to deflections during vibration in the board and differential deflections occurring as a result of differences in thermal coefficients of expansion between the components and the board. After a finite number of deflections between board and components, fatigue failures occur. Service life within a surface mount solder fillet follows mechanical failure models. These models predict failure at a predetermined number of cycles for different stress levels in the solder fillet. This paper specifically addresses multiple solder issues impacting avionic integrity. These topics are fatigue in surface mount devices, castellations and surface finishes, 1 ife predictions, design criteria, manufacturing processes and controls, accelerated fatigue testing, and quality assurance provisions for solder joints. Each topic will be introduced with a question expressing a concern relating to avionics integrity and a discussion relating to each topic follows.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1990
- Accession Number
- ADA578182
Entities
People
- Cynthia L. Lingg