Date of Award

8-2025

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Committee Advisor

Philip King

Second Committee Member

Ahmed Aboelezz

Third Committee Member

Bashir Khoda

Abstract

This work explores binder-jet printed parts’ material properties with regard to their application to simulation. The objective of this work is to establish a more diverse selection of experimental methods used to characterize binder-jet printed material’s bulk properties, leading to more accurate modeling.

The results of density and surface roughness measurements are discussed along with their implications. Samples of binder-jet printed material were scanned by X-ray profilometer to determine their density and examined using optical microscopy to determine their surface roughness. Density of printed sand samples was found to vary based on part orientation relative to the travel direction of the printer recoater. Surface roughness was found to be influenced by multiple factors (part orientation relative to printer x- and y-axes, face orientation relative to the vertical, etc.), each changing the surface roughness by up to 13%.

The results of various thermal analyses of both raw silica foundry sand and a mixture of silica foundry sand with proprietary binder used in a commercial binder-jet printer are presented. Silica foundry sand was examined to provide a baseline for the binder-jet printed material. Thermogravimetric analysis of the sand-binder mixture gave indications of the decomposition of the proprietary binder at temperatures commonly seen in metal casting, a key application for binder-jet printed material. Transient Plane Source measurements provided an indication of the thermal diffusivity of the binder-jet printed material at room temperature. Differential Scanning Calorimetry measurements provided indication of the specific heat capacity of the sand-binder mixture. At low temperatures, sand and the sand-binder mixture were demonstrated to have similar specific heat capacities.

A macroscopic experimental method to measure bulk thermal properties of binder-jet printed material is presented along with the results of experiments performed with this method. Printed samples were instrumented and then heated in a custom-built furnace; the temperature of the samples at select radii were recorded and analyzed. The Fourier analysis method is used to determine the specific heat capacity and thermal conductivity of the binder-jet printed material from these temperature measurements. These resulting material properties were applied to a simulation of the experimental method. While thermal analyses agreed broadly with the experimental method’s analyzed results, the experimental method and the simulation results did not.

The shortcomings of the thermal analyses, macroscopic experimental method, and accompanying simulation are presented, along with suggestions for improvements to the experimental method. Follow-on work can use this work’s methods and results to provide more realism in modeling casting events.

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