The House of High Quality Articles for Everyone in the World

May 11, 2010

Quality Function Deployment (QFD)

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.

The Process:
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.