A novel solid freeform fabrication method has been developed for the manufacture of
ceramic-based components in an environmentally friendly fashion. The method is based on the
extrusion of ceramic slurries using water as the binding media. Aluminum oxide (Al2O3) is
currently being used as the part material and solids loading as high as 60 vol. % has been
achieved. This paper describes a manufacturing machine that has been developed for the
extrusion of high solids loading ceramic slurries. A critical component of the machine is the
deposition system, which consists of a syringe, a plunger, a ram actuated by a motor that forces
the plunger down to extrude material, and a load cell to measure the extrusion force. An
empirical, dynamic model of the ceramic extrusion process, where the input is the commanded
ram velocity and the output is the extrusion force, is developed. Several experiments are
conducted and empirical modeling techniques are utilized to construct the dynamic model. The
results demonstrate that the ceramic extrusion process has a very slow dynamic response, as
compared to other non-compressible fluids such as water. A substantial amount of variation
exists in the ceramic extrusion process, most notably in the transient dynamics, and a constant
ram velocity may either produce a relatively constant steady-state extrusion force or it may cause
the extrusion force to steadily increase until the ram motor skips. The ceramic extrusion process
is also subjected to significant disturbances such as air bubble release, which causes a dramatic
decrease in the extrusion force, and nozzle clogging, which causes the extrusion force to slowly
increase until the clog is released or the ram motor skips.Mechanical Engineerin