MICROFUSION AND WAXES
Microfusion, also known as lost wax casting, uses sacrificial models identical to the geometries of the piece to be produced in metal. The sacrificial models, commonly known as waxes, are made in special materials that are designed to liquefy and burn at relatively low temperatures and not leave ashes. The sacrificial models are used to create a structure known as the cluster in which the pieces are the “grains” of the bunch and the “stalk” is the feeding channel for the molten metal. This wax structure is embedded in an inert material (gypsum or liquid ceramic) and then placed in cooking.
During cooking the refractory solidifies and the waxes dissolve, leaving a cavity identical to the pieces with the casting system. The result is a hollow shell that can then be filled with aluminum (if the shell is in plaster) or with steel (if the shell is in ceramic). The ceramic shell is considerably more resistant but to create it a very long process is necessary (it is obtained by immersing the cluster in the “barbottina”, the liquid ceramic, drying and repeating this sequence many times).
They can be obtained by direct printing of digital polystyrene (very fast and cheap, but with a rough surface finish and with a precision of ± 0.16mm) or by wax casting in silicone molds obtained with stereolithographic masters. The latter are perfectly compact and have a level of detail of ± 0.05mm.
Microfusions are characterized by a very high resolution up to ± 0.05mm) but due to the very high number of layers used to build the pieces, parts with dimensions greater than 120mm in height tend to have very high costs. In Prototype you can make monolithic objects up to 350mm in size.