Material considerations circuit board design

Have the appropriate stencil or screen design and materials (e.g., thickness, aperture geometry, wall finish, etc.) for the circuit board product. Design considerations must also address the need to widen fine-pitch aperture openings slightly for printing Pb-free solder paste. 

Design considerations for these applications must include thermally conductive parts (heat sinks) for removing heat from the circuitry involved. The circuitry may or may not be encapsulated. In confined circuitry, as on a printed-circuit board, nonencapsulated heat sinks bonded in place are one solution. In this case, aluminum is usually the preferred heat-sink material because of its lightweight and high thermal conductivity. If good dielectric properties are required, a high concentration of inorganic or mineral fillers can be used. 

---