In order to determine which die cast prototyping process is the right one for you, you must understand that the die casting technique used to make production castings is inherently different from the methods commonly used to construct prototypes. Due to this and the differences that exist between the alloys used in die casting and other casting methods, your prototype is probably going to have different characteristics than a production casting would have.
For instance, a component made from die casting is going to have a skin that is normally around 0.5mm thick. This skin gives die cast parts a considerable amount of their tensile strength and fatigue life. While the skin is a vital component of a die cast casting, a finished machined prototype must have had either a portion or all of its skin removed just to be created.
Given that the die casting process involves certain steps such as rapid cooling, quick solidification and high pressure on liquid metals, among other measures, die casting gives a component mechanical characteristics that a prototype made with another method might not have. Although the difference is normally negligible, the core of a die cast item may contain porosity, which might make it less dense than castings created using alternative techniques. Depending on the die casting prototyping strategy you choose, it may be able to closely replicate many of the mechanical properties associated with die cast castings.
As a general rule, the alloys that are typically used in die casting are not appropriate to use with the gravity casting prototype process or machining from wrought or sheet because their chemical makeup is different from the chemical composition of the alloys used in the prototyping techniques. The zinc alloy group used for die casting includes Zamak 3, 5 and 7, which contain four percent aluminum. Since this group is touchy when it comes to the rate of solidification and the strength and hardness of a gravity casting are measurably less than they are in die cast castings, this group of Zamak alloys should not be used in the gravity casting prototyping process.
Instead of Zamak 3, 5 and 7, ZA alloys should be used with the gravity casting prototyping technique to better replicate the mechanical properties produced by die casting. It is okay to use Zamak 3, 5 and 7 to produce the ornamental elements of your prototype, however, as long as the mechanical properties of these pieces is irrelevant to the functionality of your prototype.