Title page for ETD etd-0429104-103828

Document Type dissertation

Author Name Kummailil, John

URN etd-0429104-103828

Title Process Models for Laser Engineered Net Shaping

Degree PhD

Department Manufacturing Engineering

Advisors
Professor Christopher A. Brown, Advisor
Professor Kevin (Yiming) Rong, Committee Member
Professor William C. S. Weir, Committee Member
Mr. Carmine Sammarco, Committee Member
Dr. David Skinner, Committee Member

Keywords
rapid prototyping
solid freeform fabrication
LENS
laser engineered net shaping
laser
titanium

Date of Presentation/Defense 2004-04-19

Availability unrestricted

Abstract
The goal of this dissertation is to develop a model relating LENS™ 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.

Files
jkummailil.pdf

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Document Type	dissertation
Author Name	Kummailil, John
URN	etd-0429104-103828
Title	Process Models for Laser Engineered Net Shaping
Degree	PhD
Department	Manufacturing Engineering
Advisors	Professor Christopher A. Brown, Advisor Professor Kevin (Yiming) Rong, Committee Member Professor William C. S. Weir, Committee Member Mr. Carmine Sammarco, Committee Member Dr. David Skinner, Committee Member
Keywords	rapid prototyping solid freeform fabrication LENS laser engineered net shaping laser titanium
Date of Presentation/Defense	2004-04-19
Availability	unrestricted
Abstract The goal of this dissertation is to develop a model relating LENS™ 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.
Files	jkummailil.pdf