Faculty Advisor or Committee Member

Professor Christopher A. Brown, Advisor

Faculty Advisor or Committee Member

Professor Kevin (Yiming) Rong, Committee Member

Faculty Advisor or Committee Member

Professor William C. S. Weir, Committee Member

Faculty Advisor or Committee Member

Mr. Carmine Sammarco, Committee Member

Faculty Advisor or Committee Member

Dr. David Skinner, Committee Member

Identifier

etd-0429104-103828

Abstract

The goal of this dissertation is to develop a model relating LENSâ„¢ process parameters to deposited thickness, incorporating the effect of substrate heating. A design review was carried out, adapting the technique of functional decomposition borrowed from axiomatic design. The review revealed that coupling between the laser path and laser power caused substrate heating. The material delivery mechanism was modeled and verified using experimental data. It was used in the derivation of the average deposition model which predicted deposition based on build parameters, but did not incorporate substrate heating. The average deposition model appeared capable of predicting deposited thickness for single line, 1- layer and 2-layer builds, performing best for the 1- layer builds which were built under essentially isothermal conditions. This model was extended to incorporate the effect of substrate heating, estimated using an energy partition approach. The energy used for substrate heating was modeled as a series of timed heating events from an instantaneous point heat source along the path of the laser. The result was called the spatial deposition model, and was verified using the same set of experimental data. The model appeared capable of predicting deposited thickness for single line, 1- layer and 2- layer builds and was able to predict the characteristic temperature rise near the borders as the laser reversed direction.

Publisher

Worcester Polytechnic Institute

Degree Name

PhD

Department

Manufacturing Engineering

Project Type

Dissertation

Date Accepted

2004-04-29

Accessibility

Unrestricted

Subjects

rapid prototyping, solid freeform fabrication, LENS, laser engineered net shaping, laser, titanium, Pulsed laser deposition, Titanium, Prototypes, Engineering

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