For die castings, it is very important to avoid sharp corners,especially when they are associated with a rapid change in cross section. Whenever possible,an inside corner should be designed with a fillet – an outside corner with a radius. This is necessary to ensure good results when plating operations are a requirement. Eliminating sharp inside corners also gives added strength to the casting and can improve fill by reducing turbulence. Radii & fillets as small as .005” can make noticeable improvements to a casting.
The major purpose of adding fillets and radii is to avoid high stress concentrations in both the die castings and the die casting die, in order to reduce die maintenance costs and increase the life of the die.
In the sketches below, consideration has been given to the normal stresses on the die cast part in use and to the stresses induced in the die castings by the casting process itself, as well as to other manufacturing and die maintenance considerations.