Robot Mechanisms and Mechanical Devices Illustrated - Profe Saul

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Introduction
ton. This process is repeated until the 3D model is complete. Any loose
excess powder is brushed away, and wax is coated on the inner and outer
surfaces of the model to improve its strength.
The 3DP process was developed at the Three-Dimensional Printing
Laboratory at the Massachusetts Institute of Technology, and it has been
licensed to several companies. One of those firms, the Z Corporation of
Somerville, Massachusetts, uses the original MIT process to form 3D
models. It also offers the Z402 3D modeler. Soligen Technologies has
modified the 3DP process to make ceramic molds for investment casting.
Other companies are using the process to manufacture implantable
drugs, make metal tools, and manufacture ceramic filters.
Direct-Shell Production Casting (DSPC)
The Direct Shell Production Casting (DSPC) process, diagrammed in
Figure 7, is similar to the 3DP process except that it is focused on forming
molds or shells rather than 3D models. Consequently, the actual 3D
model or prototype must be produced by a later casting process. As in the
3DP process, DSPC begins with a CAD file of the desired prototype.
Figure 7 Direct Shell Production Casting (DSPC): Ceramic molds rather than 3D models
are made by DSPC in a layering process similar to other RP methods. Ceramic powder is
spread by roller over the surface of a movable piston that is recessed to the depth of a single
layer. Then a binder is sprayed on the ceramic powder under computer control. The
next layer is bonded to the first by the binder. When all of the layers are complete, the
bonded ceramic shell is removed and fired to form a durable mold suitable for use in metal
casting. The mold can be used to cast a prototype. The DSPC process is considered to be
an RP method because it can make molds faster and cheaper than conventional methods.