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Quality Function Deployment

written by: H. Rassouli • edited by: Lamar Stonecypher • updated: 5/23/2011

Quality Function Development techniques achieve tangible quality improvements with sustainable productivity by interpreting customer's needs and requirements implied in the voice of customer into product specification for achieving cost effective top quality end products and prompt services.

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    Introduction

    Interpreting customer needs and wants into product specification is the major concern of product designers and Quality Function Deployment is the tool for product designers to turn these requirements which are implicitly expressed in the voice of customer into technical terms to define product specification. QFD can meet the quality that the customer wants and the functions that the products should serve, and defines the explicit relationship between product characteristics and customer requirements.

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    What is the Importance of quality function deployment?

    Quality function deployment is a challenge of enhancing effective and efficient productivity strategies for sustaining high quality and marketing competitiveness. It is a planning system that addresses many facets of quality achievements. QFD techniques achieve tangible quality improvements with sustainable productivity by interpreting customer's needs and requirements implied in the voice of customer into product specification for achieving cost effective top quality end products and prompt services. QFD is a mean to translate whats into hows, to interpret the colloquial and non-technical language of the customer into the technical terms of product specifications. QFD is applicable, and has been applied, in a vast variety of design, manufacturing, and service cases. There is certain evidence of QFD application in design of medical devices, construction projects, software engineering, evaluation of technical text books, lean manufacturing systems, and many other industrial and service cases. Readers are referred to QFD Institute publications to learn more about examples of such evidences.

    Figure 1 Figure 2 

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    How does QFD translate Whats into Hows?

    In QFD applications Whats are translated into Hows through a series of matrices in which defined Hows of the first matrix becomes Whats of the second one, defined Hows of the second matrix becomes Whats of the third one, and so forth, until some quantitative and measurable figure is reached.

    The first matrix is usually the Product Planning Matrix followed by the Concept Selection Matrix, multiple Subsystem/Subassembly/Part Deployment Matrices, Process Planning Matrix, and Production Planning Matrix.

    Figure 3 Figure 4 

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    Synopsis

    Quality Function Deployment (or QFD) was developed in Japan by Dr. Yoji Akao in 1966. This method emphasizes user demands in producing high quality end products. In order to enhance intrinsic quality functions, quality assurance and quality control parameters were linked together into Value Engineering.

    Value Engineering is a methodical system for improving the value of end products and services by scrutinizing the functions of the product. The Quality Value is a ratio of function to its cost. The ultimate goal is to improve functions at a lower cost of production.

    Six Sigma is a registered trademark and business management action plan developed by Motorola, USA in 1981. Its aim is to improve entire processes to the top quality level. The probable maximum defects level is restricted to 3.4 defects per million opportunities.

    The ISO 9000:2000 Standard also ensures customer satisfaction.

    QFD helps planners focus on features of the existing product, and also the criteria of service and marketing view points. The QFD technique yields useful visualization tools in the form of graphs and matrices.

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    The Following Techniques are used in QFD

    • Affinity Diagrams depict customer requirements and service facilities.
    • Relations Diagrams show priorities and root causes of Process problems and customer needs.
    • Hierarchy Trees are loaded with checklists of missing data.
    • Process Decision program charts help avoid costly mistakes.
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    Affinity Diagrams

    An affinity diagram organizes ideas into common themes and is basically the starting point of the QFD analyzing System.

    Probably it is not a bad thing to have lots of ideas, and when a wealth of ideas is available, using them effectively is made easier by analyzing affinity diagrams. The very important information can be structured precisely in these diagrams.

    The affinity diagram helps to assimilate large amounts of data related to relationships between ideas. This method is also referred as the KJ method, as Kawakita Jiro (a Japanese anthropologist) developed it.

    Affinity Diagram 

    Affinity Diagram 001 

    Affinity Diagram 002 

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    Affinity diagrams are brainstorming exercises that can be used in situations where a solution is not readily available, many variables have to be reckoned, and concepts and ideas need to be discussed. Root causes of failure modes can also be identified easily.

    Affinity diagrams are great tools for understanding large amounts of information. By working backward to probe broad themes, an insight can be visualized in which you could not find these details otherwise.

    Using the affinity diagram approach discovers hidden linkages. The affinity diagram precisely gives a vista vision of hidden information.

    Relations Diagrams show different relationships between factors, areas, or processes. They are worthwhile as it makes easy to pick out the salient factors adequately.

    There are four types of Hierarchy Trees, namely – Function hierarchy tree, Data hierarchy tree, Notes hierarchy tree, and Attribute hierarchy tree.

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    Process decision program chart

    The PDPC chart methodically identifies what can go wrong in Planning, Development, and Manufacturing. The Counter-measures action plan is prepared well in advance to avert costly failures.

    This is a tree diagram which has three levels. The high level depicts the objective. The second level shows main activities. and the third level defines the tasks needed to accomplish the approved main activities. Problems are displayed in the fourth level.

    A brainstorming session is conducted at the third level to identify and avoid what can go wrong in the system. Practical and impractical countermeasures are coded to avoid misuse.

    All the potential problems located in the fourth level are intensely reviewed. All the countermeasures action taken is recorded in the fifth level.

    The checklist is an important document with rules to be strictly observed in planning, production, quality assurance, stores, dispatch, and service departments.

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    Ishikawa Diagrams

    Ishikawa diagrams are known as 'fishbone" or "cause and effect" diagrams. These diagrams are considered one of the seven basic tools of quality management, along with the Affinity Diagrams.

    The 6 M’s Fishbone template is generally used by manufacturers. 6 M’s refer to Machine, Method, Materials, Maintenance, Man, and Mother Nature (Environment). You can use the map by selecting any of these: Equipment, Process, People, Materials, Environment, and Management.

    Please Note: These images are dummy templates.

    You can download the templates from this website. Data can be entered into the templates for analysis.

    http://www blog.mindjet.com/2009/.../3-free-fishbone-diagram-templates –

    4 S Fishbone Analysis Template  6P Fishbone Analysis Template 8P Fishbone Analysis Template