Development of a Relational Heat Transfer Model for Additive Manufacturing

Open Access
Author:
Park, Joshua Zane
Area of Honors:
Engineering Science
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Richard Martukanitz, Thesis Supervisor
  • Judith A Todd, Honors Advisor
  • Albert Eliot Segall, Faculty Reader
Keywords:
  • Additive Manufacturing
  • 3D Printing
  • Directed Energy Deposition
  • Calorimetry
  • Thermal Response
  • Energy Balance
  • Energy Absorption
Abstract:
This thesis presents the results from experimentation performed to determine several key input parameters for the future development of a proposed phenomenological, quasi-empirical model for the heat transfer of select Additive Manufacturing techniques through the use of an analytical energy balance. Two sets of experiments were designed to directly measure or determine several model inputs, including maximum melt pool temperatures, surface temperatures, and energy absorption coefficients for a variety of materials and power settings. A calorimetry technique was developed and used to determine the energy absorption coefficient, β, for both Ti-6Al-4V and Inconel 625 using a series of substrate tubes and deposition processes. The determined results demonstrate good agreement between each experiment, and display differences based on material type and input power settings. A second set of experiments examined the thermal responses experienced in the deposition melt pool and on the substrate surface during a laser deposition process. The Ti-6Al-4V samples demonstrated maximum temperatures below the melting point of the material, suggesting measurement errors associated with the experimental setup; while the Inconel 625 sample exhibited a set of temperature measurements above the liquidus temperature of the material, suggesting that actual melt pool temperatures were recorded. Finally, these data sets were analyzed and presented as viable inputs for a future energy balance model for Directed Energy Deposition processes, and the future development of the model was discussed.