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What Is Quality Function Deployment?

Quality Function Deployment (QFD) is a set of powerful product development tools that were developed in Japan to transfer the concepts of quality control from the manufacturing process into the new product development process. The main features of QFD are a focus on meeting market needs by using actual customer statements (referred to as the "Voice of the Customer"), its effective application of mutlidisciplinary teamwork and the use of a comprehensive matrix (called the "House of Quality") for documenting information, perceptions and decisions. Some of the benefits of adopting QFD have been documented as :

    • Reduced time to market
    • Reduction in design changes
    • Decreased design and manufacturing costs
    • Improved quality
    • Increased customer satisfaction

     

    Yoji Akao is widely regarded as the father of QFD and his work led to its first implementation at the Mitsubishi Heavy Industries Kobe Shipyard in 1972. The interest in QFD in the West was stimulated by reports of the achievements made by Toyota through its application between 1977 and 1984. These included a reduction in product development costs by 61%, a decrease in the development cycle by one third and the virtual elimination of rust related warranty problems.

    Yoji Akao defined QFD as "a method for developing a design quality aimed at satisfying the consumer and then translating the consumer's demands into design targets and major quality assurance points to be used throughout the production phase".

    The main features of QFD are its focus on meeting customer needs through the use of their actual statements (termed the "Voice of the Customer"), its facilitation of multidisciplinary team work and the use of a comprehensive matrix for documenting information, perceptions and decisions. This matrix is commonly referred to as the "House of Quality" and is often perceived to represent QFD in its entirety.

    In addition to the "House of Quality" matrix, QFD utilises "Seven Management and Planning Tools"which are used in many of its procedures:

    1. Affinity diagrams.

    2. Relations diagrams.

    3. Hierarchy trees.

    4. Matrices and tables.

    5. Process Decision Program Diagrams (PDPC)

    6. The Analytic Hierarchy Process (AHP)

    7. Blueprinting

The "House of Quality" matrix is the most recognised form of QFD. It is utilised by a multidisciplinary team to translate a set of customer requirements, drawing upon market research and benchmarking data, into an appropriate number of prioritised engineering targets to be met by a new product design. There are many slightly different forms of this matrix and this ability to be adapted to the requirements of a particular problem or group of users forms one of its major strengths. The general format of the "House of Quality" is made up of six major components which are completed in the course of a QFD project:

 

    1. Customer requirements (HOWs) - a structured list of requirements derived from customer statements.

    2. Technical requirements (WHATs) - a structured set of relevant and measurable product characteristics.

    3. Planning matrix - illustrates customer perceptions observed in market surveys. Includes relative importance of customer requirements, company and competitor performance in meeting these requirements.

    4. Interrelationship matrix - illustrates the QFD team's perceptions of interrelationships between technical and customer requirements. An appropriate scale is applied, illustrated using symbols or figures. Filling this portion of the matrix involves discussions and consensus building within the team and can be time consuming. Concentrating on key relationships and minimising the numbers of requirements are useful techniques to reduce the demands on resources.

    5. Technical correlation (Roof) matrix - used to identify where technical requirements support or impede each other in the product design. Can highlight innovation opportunities.

    6. Technical priorities, benchmarks and targets - used to record the priorities assigned to technical requirements by the matrix, measures of technical performance achieved by competitive products and the degree of difficulty involved in developing each requirement. The final output of the matrix is a set of target values for each technical requirement to be met by the new design, which are linked back to the demands of the customer.