T300 Graphite Core Printed Wiring Board: Predicting the Coefficient of Thermal Expansion Available to Purchase

Materials with low thermal expansion rates are being used in printed wiring boards (PWBs) to obtain a thermal expansion factor compatible with that of surface mounted leadless ceramic chip carriers (LCCCs), thus improving solder joint survivability and reliability. Boeing Electronics Company (BECo) selected T300 graphite, a constraining core material, as its baseline in establishing methodology for predicting and then measuring coefficient of thermal expansion (CTE). Predicted results from the Interactive Composite Analysis Program (INCAP) were compared with CTE measurements derived from a relatively new strain gauge technique.