When joining aluminum for aerospace electronics, brazing often is the most practical choice for creating a continuous all-metal joint interface.
Because of its light weight and excellent thermal conductivity, aluminum often is the material of choice for assemblies that house or cool airborne electronics.
Aluminum’s properties are particularly important in combat aircraft. Weight minimization becomes a major design consideration for many components going into these aircraft. Thermal conductivity is especially important in the electronics packages because of the heat problems created by the dense packing of powerful systems in limited spaces. The complex aluminum enclosures, chassis and heat dissipators used in military avionics systems often are manufactured from numerous individual components, which must then be joined.
Selection of a joining process must be based on a thorough analysis of the service requirements and materials involved. For example, the joint’s mechanical strength properties often are critical. A structural joint usually requires good tensile and shear strength as well as resistance to fatigue from cyclic vibrations. Thermal conductivity of the joint is essential for heat exchangers and heat dissipators.
Electrical conductivity also may be important in some applications. In addition, the service environment must be considered, particularly when the joint will be exposed to temperature extremes, moisture or other corrosive media.
In enclosures, shielding sensitive electronic components from electromagnetic interference (EM!) often is critical. Certain joining processes provide joints with better EMI shielding characteristics than do others. by J.E. Pritchard & R. Laub