Characterizing Airplane Environments in Commercial Airplanes Using On-Board Test Vehicles to Evaluate State-Of-The-Art Lead-Free Alloys
Authors: Joseph M Juarez, Jr, Ph.D.; Connie M Borror, Ph.D.; David Redman, Ph.D. Company: Honeywell International, Arizona State University, Texas A & M University Date Published: 5/19/2015
ICSR (Soldering and Reliability)
Abstract: Test vehicles have been used extensively for evaluation of lead-free solder alloys in high reliability electronics. These tests have been limited to laboratory tests consisting of either thermal or vibration testing alone or in some cases combined environments. These tests are accelerated and not representative of in-service life that can span 20 years or more for highly reliable commercial airplane applications. This effort is aimed at evaluating a variety of lead free solder alloys using test vehicles in actual in-service military and commercial flights to represent actual failure times. Motivation for this study stems from the lack of predictive models for solder alloys. Models are being proposed, but are several years away because they must include combined thermal cycling and random vibration environments that have validated acceleration factors before durability of highly reliable products can be qualified by similarity. Presented is a project to focus laboratory testing by understanding the real environments more fully to inform tests that can ultimately simplify the modeling necessary for robust designs. This approach utilizes the environmental factors characterizing airborne application environments including temperature, vibration, and humidity recorded by on-board equipment and considered as covariates in the failure analysis. The design factors include solder alloy, board finish, and component type with tin-lead as a baseline solder alloy. This design proposal represents an approach to understanding how these various alloys being considered for high reliability applications compare in combined harsh flight environments.
In-service reliability, test vehicle, durability, lead-free solders, random vibration