141 Overview

It is well known that product cost is largely dependent on decisions made during its development stage [1]. As a product evolves through its development stage, it becomes difficult to alter design and manufacturing approaches without incurring additional cost. In fact, such design changes can be so costly as to affect adversely the financial health of a company. An example of this is the delay and

Handbook of Advanced Materials Edited by James K. Wessel ISBN 0-471-45475-3 Copyright © 2004 John Wiley & Sons, Inc.

design changes that Rolls-Royce and Lockheed suffered during the development of the Rolls-Royce RB211 engine for the L-1011 aircraft [2]. The cost of changing the fan blade material from a composite material to a titanium alloy was so significant that Lockheed was forced from the commercial airliner business. It is not supposed here that if Lockheed had rapid manufacturing technology available to it during the 1970s that its problems could have been avoided. However, the example illustrates the degree in which early design and manufacturing decisions affect the profitability of a company.

From the observation that product costs are largely a result of poor conceptualization during the product development stage, the concepts of rapid prototyping and rapid manufacturing emerged. There are many rapid prototyping concepts, and these have been reviewed [3, 4] in detail. This chapter will address laser-based solid free-form fabrication techniques.

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