Copyright © 2004 by ASME 1
`Proceedings of DETC ‘04:
ASME 2004 International Design Engineering Technical Conferences
And Computers and Information in Engineering Conference
September 28-October 2, 2004, Salt Lake City, Utah
DETC2004-57221
DRAFT
PROTOTYPE PARTITIONING BASED ON REQUIREMENT FLEXIBILITY
R. E. Moe
Department of Mechanical Engineering
The University of Texas at Austin
Austin, TX 78712
smerk1234@hotmail.com
Daniel D. Jensen
U.S. Air Force Academy
Dept. of Engineering Mechanics
USAF Academy, CO 80840-6240
Dan.jensen@usafa.af.mil
Kristin L. Wood
Department of Mechanical Engineering
The University of Texas at Austin
Austin, TX 78712
wood@mail.utexas.edu
ABSTRACT
Prototype partitioning is an often-overlooked step in
the product development process that has great potential for
improving project success. This paper discusses the
importance of applying a systematic prototype partitioning
strategy to a product development project. Quite often,
prototypes are chosen based on historical reasons, with the
premise that requirements are rigid and inflexible.
Alternatively, a method is proposed here for prescribing a
partitioning strategy that is tailored to the specific
characteristics of a project and is based upon the three
components of requirement flexibility: cost, schedule, and
performance. By considering the realistic flexibility in these
requirements, strategic prototyping decisions may be made to
promote the success of a development project. Three product
development applications illustrate the proposed method: the
Black & Decker SnakeLight ™, a senior-level design project
at the United State Air Force Academy, and the product
development of a new umbrella concept based on compliant
components.
1.0 INTRODUCTION
A broad definition of a prototype is a simplification of a
product concept meant to resolve issues in product
development (Otto, et al. 2001). These issues may include
customer needs, manufacturability, technical performance,
market analysis, product liability, aesthetics, ergonomics, and
product theme among others. Inasmuch as effective
prototyping hinges upon planning, a key to improving
prototyping effectiveness, and thereby product development
success, is to improve the prototype planning process. This
planning process, including the allocation and division of
prototyping tasks, is what we refer to as prototype
partitioning.
There is a significant investment at stake in product
development. Depending on the industry, companies will
spend 2-8% of sales on R&D. In spite of this, there are
estimates that 40-46% of product development resources are
spent on products that are cancelled or do not yield adequate
returns (Cooper 1993). Product development project
cancellation rates are reported to be between 30-50% (Ulrich,
et al. 2000; Linberg 1999; Galal, et al. 1999; Patel 1999).
Although there are many reasons for the failure of product
development projects, two types of risks can be mitigated.
First, excessive resources might be spent to determine that a
project is not worth pursuing. These are wasted resources that
could be applied to other projects. Second, resources might be
directed away from a project that is worthwhile. This case
represents a lost opportunity. Both of these issues may be
mitigated using the correct application of the information from
the product requirements.
In addition to these resource management issues, many
products that enter the market have not been developed to
their full potential. This reduced potential may be associated
with many aspects of the product development process.
Decisions regarding prototyping are one such aspect.
Effective prototype decisions, such as how many concepts to
prototype simultaneously, how the information is used to
sequence the prototypes, and whether replanning of the
prototype strategy is needed based on testing results, are