Formulation of gypsum powder and binder for use in 3D print prototype was developed. The 3D printing technique consists of the three-dimensional deposition of binders on successive layers of powder slices; the binder reacts with the powder and consolidates the two-dimensional format of each printed section, which added to subsequent slices consolidates the three-dimensional model. Although this model of three-dimensional printer is becoming popular mainly for its low cost, powder and binder are the greater obstacles due to their high cost. In this project formulations of powders, obtained by grinding the gypsum in alcoholic medium with binders and additives followed by agglomeration of fine particles of gypsum were developed. Formulations of binders based on the reaction of gypsum, considering the binding affinity and the operation of the print head were proposed and tested. The conditions of the agglomerated powder to the uniformity of the deposition layers and the minimum requirement of the binder for the operation of the print head were evaluated. Bar shaped specimens were produced on commercial 3D printing equipment and analyzed with respect to flexural strength, density and dimensional shape. Specimens from the powder were obtained with addition of 5 vol.% PVB and binder with 90 vol.% of distilled water and resistivity of 290 kΩ that showed an average flexural strength of 0.33 MPa, which was enough for initial handling, with simplified manufacture and a very economical cost.
tridimensional printing; rapid prototype; binder; gypsum powder
