The design goal in weight reduction of die casting parts is to minimize the volume of material components and save weight and cost in die casting. The more the amount of metal in the components, more will be the time to fill the die cavity and to cool the metal before ejection.
Moreover, pockets can be used to make thinner cross sections and ribs can be used to strengthen if needed. The pocket location should be carefully considered, as the pockets may sometimes lead to non-constant shrinkage that can affect the accuracy of the die-casting component.
Adding Ribs
In the design stage of the die cast, you can add ribs on the thin walls die casting to help improve the strength of the component. Proper care should be taken while deciding on the rib locations, so as not to hinder the ejector pins and metal flow. If possible, you can add fillets and radii to the ribs, as this will help reduce sharp corners and changes in the cross section.
Parts Shrinkage
It is normal for the metal to shrink when it cools down from the die casting temperature to the room temperature. Theory says that the shrinkage is about 0.6% and that the shrinkage will be always to the nominal center of the casting.
This shrinkage will allow the casting to get out of the tooling cavity easily, but the casting may get locked onto any section of the die that is projecting to the casting. The die-casting designer has the option to apply draft to the component, as this will help reduce shrinkage.
Using Drafts
Draft is the small taper on the cavity side of the casting. Drafts help the die casting component eject freely after cooling down. Die casting surface with draft on it will be very much polished. If drafts are not used in casting, the caster will have to use some tolerance for draft.
Radii and Fillets
Die casting designers need to avoid rapid changes in the cross section and sharp corners. Besides, an inside corner design should include a fillet and outside corner should have a radius to avoid sharp corners. Avoiding the sharp inside corners can offer additional strength to the die casting components and also improve the filling.