QFD stands for Quality Function Deployment. Quality Function Deployment is a structured method in which
customer requirements are translated into appropriate technical requirements for each stage of product development
and production. The QFD process is often referred to as listening to the voice of the customer and is considered a
tool of concurrent engineering. Basically, QFD relates the customer requirements (product specifications) to the
product design parameters in a mathematical manner. The result of this is a product design driven by math.
The advantages that would be realized through the use of QFD include a reduction in the time required for product
design as well as a reduction is those costs associated with the process. This is possible because the design
alternatives are realized much earlier in the process thus reducing the number of corrections and design errors.
Also, a higher level of clarity for decision making is gained through the use of this tool.
There is a structure to the use of QFD. Certain steps need to be followed in order to assure the proper outcome. A
brief summary of each of the steps will aid in gaining a better understanding.
Since the customer’s input is the driving force here, Identify the customer’s requirements, listen to the “Voice of
The Customer.” Be sure that the product design decisions are based on the customer and not on what is perceived
as the customer’s needs. Refine the customer’s requirements to more specific points and determine how they can
be accomplished. A chart may be helpful at this stage.
Once these decisions and relationships have been determined, a planning matrix can be constructed. The planning
matrix determines how factors relate. The relations between the factors are analyzed to determine any design
changes If, in general, there are more negative than positive effects, the process or product should be reconsidered.
If too many changes need to be made, the customer’s requirements should be analyzed for accuracy.
The relationships between the “Whats” and the “Hows” are formed by assigning weights of 0-9, 9 being the
strongest. The column sums give importance ratings. The result should be a few clearly important design features
and a few that clearly are not.
The customer’s importance rating is compared to the calculated importance rating. Also, the competitors’ products
are rated and ranked. Analysis of these factors will determine strengths and weaknesses among the consumers and
compared to the competition. At this point, any technical deficiencies will surface as well.
A number of tools are used to determine the need for any changes. A new set of target values is developed from the
previous analysis. A degree of difficulty is determined for the product and a cost versus quality assessment is
made. Quality has a cost and a cost/benefit trade-off needs to be made. The decisions do not need to be follow the
chart directly, however changes should not deviate too significantly.
For each control characteristic selected, a deployment matrix is developed. The deployment matrix is used to do
design work, test the results, and compare them to the target values
This process is long and complex and will require a fairly-large amount of time. However, the end product will be
much more competitive and cost far less than not using this method of concurrent engineering. Most likely, the
product will also make it to market much faster.
QFD and concurrent engineering, in my opinion, are some of the best tools to be realized for product design. I say
realized because the ideas seem so obvious. It merely takes someone to have the guts to try a new idea; refine it
and implement it to show the possibilities.
3) The QFD Handbook, Jack B. ReVelle, John W. Moran, Charles A. Cox; Wiley, New York, 1998