Publication Date

Fall 2022

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Advisor

Amir Armani

Subject Areas

Mechanical engineering

Abstract

The ceramic on-demand extrusion (CODE) process is an additive manufacturing process for technical ceramics, which features an oil bath and partial drying to print stronger green bodies due to better preservation of the printed specimen structure and reduction of uneven part evaporation. A 3D printer capable of performing the CODE process is built with subsystems including motion, extrusion, and heating, and is controlled through LinuxCNC. The CODE printer and process is tested with silicon dioxide as the technical ceramic. High strength silicon dioxide parts are essential in various present-day industries such as dental, medical, and semiconductor. A 55vol% solids loading slurry feedstock is fed into the extruder and is printed in the shape of ASTM A-sized bars using specific printing parameters. The printed green bodies are subject to post-processing including drying in a humidity chamber and debinding and sintering in a sintering furnace. The density was measured at various sintering schedules for the sintered test specimens. Flexural strength values were obtained by performing a 3-point bending test according to the ASTM C1161 standard, and the mean strength values are reported. Both the density and flexural strength values are lower with printing using CODE when compared to other current additive and conventional manufacturing methods by approximately 32% and 77%, respectively. However, this can be attributed due to defects within the printed parts including porosity due to air pockets and insufficient viscosity when pre-processing the slurry and can be minimized to produce better results.

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