Test Tailoring Methodology for Impact Testing of Portable Electronic Products

his paper introduces a test methodology to examine the urability of surface mount interconnects under impact oading when a portable electronic product is dropped. onventional testing approaches that consider the agnitude of loading (total impact energy, impact direction, nd number of impacts) as the governing criterion for amage accumulation, typically report difficulties in orrelating with impact durability under field conditions. This tudy considers the specimen response near the failure site s the governing criterion. For example, impact damage ccumulated in Surface Mount Technology (SMT) nterconnects are quantified in terms of local Printed Wiring oard (PWB) flexural strain, strain rate and rigid body cceleration. This approach is based on the hypothesis that nterconnect damage is due to PWB flexure as well as nertial forces. The advantage of this approach is that the esulting damage models are applicable across different tructures and loading. An instrumented, repeatable impact est setup is developed. The design space, in terms of PWB urvature, curvature rate and acceleration, is covered by arying impact orientation, loading and boundary conditions. he resulting test matrix is replicated twice for proof of onsistency of the test data. A damage quantification echnique is proposed based on the measured histories of WB flexure and rigid body acceleration near the critical nterconnects. This technique uses time-frequency Dynamic loading plays a crucial role in the performance and reliability of electronic devices. Portable electronic devices are often subjected to impact loading during mechanical handling, accidental misuse or shipping (transportation). Hence, they are expected to be rugged and highly impact resistant. In an effort to reduce weight and size, the products are densely packed with components, housed in thin walled plastic and have other design parameters that make them susceptible to impact induced failure. Examples include cell phones, laptops, PDAs, etc. Military applications are often subjected to repetitive impacts (artillery fire), or sudden high G loading while launching or maneuvering projectiles, or ballistic impact. The final product has to be designed and tested for drop/impact loading in these environments.