Selection of Key
March 4, 2008
Evolved in order to fill missing gaps
in the design process.
More reliable practice in facilitating
key decisions in the design process
What Are Techniques?
Simply a specified manner used to
accomplish a task
Not necessarily progressive or good by
themselves, unless they are proven by
data to provide consistently improved
The intuitive processes that evolve into
good techniques takes years to formulate.
What are Methodologies?
Methodologies are defined as an
orderly arrangement applying the
principles of reasoning to scientific
and philosophical inquiry.
Often with numerical comparisons or
calculations that have been proven
successful through use.
What Specific Methodologies And
Techniques Relate To The
Concurrent Engineering Process?
Several methodologies and
techniques are useful in the
Some provide insight at the concept
level, other are very detailed and
help at the end of the design
11 Detailed examples and
further descriptions of these
technique and methodologies
Quality Function Deployment
This methodology provides a method of
rating the importance of specific product
features using customer input.
The QFD team has a clear feature priority,
and an indicator of the price this feature
combination may yield in the marketplace.
QFD is used at the concept level and helps
focus design attention on the key
It eliminates those features of low priority,
considering them wasteful.
Design For Manufacturing (DFM)
This is a method of design with the
goal of understanding the product’s
future manufacturing processes
during the design stages.
The team can minimize
manufacturing costs, and maximize
In simplest form it represents design rules
and guidelines that the design engineer
can apply, often sitting side-by-side with
the manufacturing engineer.
In more complex implementations: a
combination of simulation, manufacturing
expertise, rule and assembly analysis is
used to provide a low cost manufacturing
strategy to follow throughout the design.
Cost Driven Design (CDD)
CDD helps the team understand the
cost elements prior to designing the
Provides specific cost targets on a
sub-assembly and piece part level.
Useful in determining the specific
changes required to be made by
Design For X (DFX)
Includes many Methodologies
Emerged as a team goal where various
team members could offer their
contribution to the product.
Helps team members focus their unique
needs where “X” fits these needs
• Ex. Design for reliability, testability, quality,
saftey, compliance, assembly, etc.
Design For X (continued)
DFX is useful throughout the process
to insure key areas are highlighted
and addressed appropriately.
This is an analysis method of comparing
Useful in identifying which alternative
attributes are the better attributes.
Helps the design team gain greater insight
into the strengths and weakness of
Taguchi’s Robust Design
This is a method of design which
establishes a specific approach to design.
Objective is to minimize the deviation
from the desired target level, while
minimizing manufacturing costs.
These deviations addressed by the robust
design approach are typically due to three
areas: manufacturing process,
environment, and material variations. The
objective is to minimize the impact of
these deviations on the designed function.
Experimental Design Techniques
Typical design analysis approaches
examine the effect of varying a single
factor while holding the other factors
This method is especially useful when
product characterization of process
characterization is needed.
Design Stress Analysis
This technique uses methods of
accelerating early life failures, and
combines these with parametric stresses,
such as timing variations.
The purpose is to help understand the
weakness in the design and the weakness
of the components selected
Eliminates potential failure modes before
they get a chance to exist in the product
Benchmarking and Competitive
The techniques used establish the
required design goals.
The method is designed to functionally
benchmark the current level of functional
This methodology has emerged as a
bonafide technique for understanding
the specifics of the design.
Especially good for early customer
feedback and feedback from
Rapid Prototyping (Continued)
Many design improvements have
resulted from the use of rapid
• Ex. Ranging from major changes in the
product design to minimizing process
costs, and preventing design mistakes.
Customer Focused Design.
Provides for a significant amount of
customer input into the design process.
It requires the building of samples and
models that can be put in front of various
customers for trial and usefulness
Selection of The Appropriate
Techniques And Methodology
Several important techniques were
Selection of the appropriate ones should
be carefully thought out.
All of the above techniques require
training. It is the organization’s role to
provide the training and the support for
specific technique and methodologies.
They all are needed and a clear program
to bring them into the organization should
DFM at the Detailed Design Level
Printed Wiring Board manufacturing
Sheet metal costing tools
Design for test strategies
Mold flow analysis
Design for assembly
DFM Rules and Guidelines
The total number of parts directly
relates to manufacturing overhead
Fewer the parts the better they can
DFM at the End of the Cycle
Process tools are added,
Require reviews of manufacturing
parts to get correct input for specific
Cost Accounting Impacts
Activity Based Accounting, applying
overhead costs to activities which
Design for X
Allows design team work on certain
areas that need improvement
Steps for DFX
Identify X and team member who can focus on
Research common used methods of
Research rules used by competitors to improve
area. Identify design testing to validate
Identify modeling tools to allow comparisons of
various design alternatives
Identify modeling and testing
Provide analysis, testing modeling and feedback
to deign team
Used when there are a number of
alternatives to be used.
Especially, if everyone is not aware.
It is a matrix methodology
Taguchi’s Robust Design Approach
Use control factors so that noise
factors do not change the response
The notion of Quality Loss,- includes
loss to manufacturing, user of
product, and society in general
Statistical Process Control- insure
process variation does not exceed
Robust Design Approach
1. Design system, all desirable
functions are achieved.
2. Parametric design, determine
characteristics that affect loss and
what values should be
3. Tolerance design, selectively
reduced on basis of cost
Experimental Design Process
Analyze variation using pre-
established set of experiments.
Matrix used to allow engineer to
determine process changes that have
Design Stress Analysis
Early indicator of design problems
Overstress design using accelerated
life cycle testing methods and
combine with parametric stress
Test gives early life failures and
predicts design failures
Test series of products to determine
performance against prescribed unit
Comparisons to known good
processes in industry or industries
that have potential of nieng adapted
to your industry.
Analyze competitions products
Done through industry reports
Use trade shows as source of
competitors new products
Wax models, foam core models,
machined plastics are examples
Understand features early,
Late changes can be avoided which
will allow acceptance by customer
Customer Focused Design
Models are developed which
customers can use and give feedback
Feedback is used by team and input
is put into the next model.
Difficulties with CE Methodologies
Some techniques are acclaimed for
their success by companies, but true
impact is difficult to ascertain.
Techniques are not supported,
funded, or available within many
This chapter was a short review of some
of the key methodologies and techniques
that have added to the concurrent
The methodologies included were:
1) Quality Function Deployment (QFD).
2) Design For Manufacturing (DFM).
3) Cost Driven Design (CCD).
4) Design For X(DFX).
5) Pugh Process.
6) Taguchi’s Robust Design
7) Experimental Design Techniques.
8) Design Stress Analysis
9) Benchmarking and Competitive
10) Rapid Prototyping
11) Customer Focused Design
What Every Engineer Should Know
About Concurrent Engineering
Thomas A. Salomone