Mechanical Torque Stress Assessment for Surface-Soldered Leaded Modules
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
The surface soldering of components for assembly to a printed circuit card, or the like, leaves these surface-soldered components vulnerable to interconnection fracture during handling. A method of determining the risk of fracture is provided by an analytical model using an equation to assess design alternatives including various component carrier sizes, component sizes, material changes and application stress levels. This stress application works as follows. As seen in Fig. 1, a circuit card 1 is held in a fixture 2 that secures the bottom of card 1 against translation while the top of card 1 is displaced linearly, perpendicular to the x, y plane of card 1. The approximate shape of a card subjected to torque follows from the boundary (i.e.