Quality Function Deployment

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Quality Function Deployment (QFD) or quality function representation is a method of quality assurance . The aim of the process is the conception, creation and sale of products and services that the customer really wants. QFD includes all areas of the company in its quality responsibility.

The method of QFD as a basic concept for quality planning goes back to the Japanese Yōji Akao in 1966. The first practical application is dated 1972 at the Kobe shipyard of Mitsubishi Heavy Industries . The Toyota Motor Company Ltd. shortly afterwards took over this method and developed it further according to his own requirements. Yoji Akao's remarks were first published in the United States in 1983 . Rank Xerox and Ford were the first American companies to introduce the method. Other companies followed.

Naming

The name of Quality Function Deployment comes from Japanese. Based on the original Hin Shitsu (品質) (quality, goodness, constitution, characteristics, attributes, features), Ki Nō (機能) (function), Kai Ten (開展) (representation, arrangement, development) is a translation as "characteristic Function representation "aptly.

The English term is used in this article because QFD has become an independent term.

method

After a successful structuring and weighting of input data in the matrices of the Quality Function Deployment by tree diagrams or other management tools existent combinations of rows and columns are shown. The evaluation of the links is usually classified as "not at all", "weak", "medium" and "strong".

The addressed data are arranged as follows using a QFD-typical WHAT-HOW question:

Simple correlation principle

The following questions apply to requirements at the line level: " What does the customer need ?, What does he want ?, What is needed ?, What makes sense for everyone ?, What should be achieved ?, ..." The questions relating to the quality characteristics at the column level are: " How do you get it ?, How do you make it ?, How do you use it ?, How should that be achieved ?, ..."

The QFD matrices can be used with these questions wherever there are interfaces or transfer points. The additional tables are processed information - weightings of list properties or comparisons - which can be newly developed or taken over from existing matrices as required. A frequently used function is the correlation with itself, through which contradictions can be recognized very well.

By displaying the information in weighted list fields and by correlating the fields, QFD has various advantageous applications:

  • Preparation and clear presentation of data in the fields;
  • Showing dependencies and influences through correlation;
  • Representation of conflicting goals through information on the correlation and the additional tables.

The weighting and correlation applied can range from relatively simple math to complicated algorithms . Usually the row levels are multiplied with the correlations (not at all = 0; weak = 1; medium = 3; strong = 9) and the values ​​per column are added. A normalization to the maximum possible values ​​shows the relative values.

Potential problems and difficulties using QFD

  • Lack of competence of project and team leaders
  • A power promoter is required to coordinate competing departmental interests
  • The quality table becomes too large if the scope is not reduced in good time
  • Lack of customer and user information
  • The team does not follow the "spirit" of the QFD, but gets lost in the "form"

Potential benefits of using QFD

  • High quality results
  • Difficult requirements and conflicting goals are identified early on
    • thereby: better use of resources
    • thereby: acceleration of the development time
    • thereby: cost reductions possible
  • Optimal coverage of customer requirements (customer-oriented)
  • The draft is of high quality, so later changes can be avoided (otherwise cost explosion see "Rule of Ten")
  • Integration of all areas involved, improvement of cooperation
  • Relationships are documented
  • Decisions become comprehensible
  • Customer requirements are formulated in a solution-neutral and benefit-oriented manner
    • thereby: better understanding of the "true" customer wishes (VOC)
    • thereby: they open up approaches for new (product) ideas

The "ideal" QFD team

QFD is a team-oriented method system with a moderator. The right composition of the team is very important, as the core work is done in workshops. The composition of the team can vary depending on the project, but the “core team” should remain the same throughout if possible. In order to be able to guarantee the holistic view, as many different areas of the company as possible but also important customers should be represented. For example key accounts, product managers, sales, development, etc.

QFD to Akao

The developer of QFD Yōji Akao coined the following sentence regarding his methodology:

"Copy the spirit, not the form."

He wanted his method not to be copied matrix by matrix, but rather that QFD should remain flexible and adapt new functionalities as required.

According to Yoji Akao, a comprehensive QFD system must include not only quality development but also technology, reliability and cost developments. The degree of specification must increase in the course of development and the transfer of information must be guaranteed. Yoji Akao implements this using so-called information paths, which generally retain a degree of detail (level of detail when processing the product / process) and transfer information in the list fields from a matrix to other matrices and tables. Changes in a list can be immediately transferred to the linked matrices and tables through the information paths. This reduces the risk of inconsistent changes and updating of contexts.

Correlation matrices

The coherent presentation of the individual elements (matrices, tables, lists, ...) enables the requirements to be conveyed, converted and linked across the concretisation levels in the product creation process with weightings. Yoji Akao's flowchart has proven itself in many cases, but should not be regarded as fixed, but rather helps to develop your own variant. The individual matrices should be combined with one another; Additions and changes to existing matrices are possible at any time. The QFD methodology should not record and improve all data correlations and process steps, but only analyze and improve important and critical features more precisely. The aim is to keep the method as small as possible and to work as precisely as possible.

The structure of the QFD according to Yoji Akao has four horizontal levels, which show increasing concretization from top to bottom:

  • Customer demands
  • Functions
  • Quality features
  • Parts

In the vertical direction, the fields are differentiated according to their content:

  • quality
  • technology
  • costs
  • reliability

The QFD method, developed by Yoji Akao, is characterized by basic analysis, evaluation and documentation skills. The developer attaches importance to improving existing products and processes, whereby he provides for technological leaps. According to Akaos, the QFD method is never intended as a complete work for creating a product, but should implement the interface between customer requirements and product features in the best possible way. Yoji Akao attaches great importance to observing these customer requirements in every development phase. On the other hand, it gives the designer a trend-setting method for identifying bottleneck parts that can be flexibly adapted to company needs.

Yoji Akao does not go into error-finding methods, the specific technology selection or the finding of innovations, he leaves these to conventional procedures. However, there are links in this regard, but these are not explicitly carried out.

House of Quality

The current literature often speaks of a house of quality (HoQ). This means the first matrix at Akao . Here, customer requirements are correlated with quality features, whereby the customer requirements as well as the quality features are correlated with themselves and form the so-called "roof" of the HoQ. Most of the practical applications of QFD usually do not go beyond the implementation of the HoQ, as there is a correlation with other topics such as B. the functions is associated with a lot of work. The HoQ is mostly used for marketing and technology correlation. Further development takes place conventionally, the additional possibilities of the QFD method are dispensed with.

QFD after Bob King

The further development of the Quality Function Deployment by Bob King has further aspects in order not to leave the method in isolation. An integration into the construction planning process as well as into the production planning process has become possible. The extended method is the entire QFD “tool kit”, whereby only individual matrices and methods should be selected as required. In his book Better design in half the time, Bob King shows practical recommendations for the sensible selection of the individual matrices .

Development of the extended method

Bob King is a student of Yōji Akao , the developer of the Quality Function Deployment method . In 1983 he began to study the method of Quality Function Deployment in the United States of America. From 1985 he deepened his knowledge with Professor Yoji Akao in Japan. In 1988, Bob King published his book Better designs in half the time in the United States . It contains a number of additional additions and aspects based on the original QFD concept. The essential addition is the integration of the Pugh concept selection analysis into the QFD. Further practically oriented additions by Fukahara from the American Supplier Institute in Dearborn , Michigan , are matrices for process development.

Matrix of matrices

The picture shows the matrix of Bob King's matrices, columns A to D (quality development, special charts, technology development and reliability development) come from Yoji Akao's approach. Columns E (new concepts) and F (auxiliary methods) as well as row five (process development) are innovations introduced by Bob King, in which process development (G1 to G6) is indicated by a dashed frame and concept planning (new concepts) by S. Pugh a gray background is marked.

Matrix of matrices

The matrices of Yoji Akao

In the matrix of matrices (MdM) shown above, the matrices with the numbers A1 to A4, C1 to C4, D1 to D4 and the process development G1 to G4 correspond to the original matrices of the developer Yoji Akao. Further matrices were added to the method because, according to Bob King, the Japanese approach was too strongly geared towards reducing costs and using mastered processes and proven technologies. The Akao system was restructured by Bob King without dropping any elements. King explains this with the wish of many users for a systematic, fixed order. Therefore the matrices of Akao are adapted to the structure of the new elements. New matrices were developed by Bob King to fill in the method gaps that QFD practitioners perceived. Especially here it is necessary to know that Bob King's matrices represent - as he says - a complete tool kit, of which only the necessary elements are to be used. In no case should it be processed matrix after matrix just for the sake of the method. It is essential that the planning team makes a sensible selection from the topics to be worked on and selects the necessary matrices.

Bob King specifies an order in processing. This sequence is a procedure that he recognizes as sensible, but which can be adapted to the circumstances at any time.

Proposal for the MdM

Auxiliary methods

The auxiliary methods are partly independent tools in the planning and analysis of products and processes. The first element mentioned is the “value engineering” analysis, which does not follow any precise scheme. The statements of the analyzes in charts B1, C2, C3, and C4 are summarized and documented in a portfolio analysis. Other methods of assessment are possible and should be used as required. Another component of a non-matrix-oriented method is the Failure Tree Analysis (FTA) and the Failure Mode and Effect Analysis ( FMEA ). Both methods are intended to monitor and identify the product features to be implemented. The third element in column F is the factor analysis developed by Ronald A. Fisher in the 1920s . This analysis combines the QFD method and statistical test planning and can be read in further literature ( lit .: Taguchi). The last element is an improvement plan in which the original goal and constructive improvements during the QFD process are entered.

QFD for development of services according to Emil Jovanov

(Source: E. Jovanov; Service-QFD, Symposion Publishing)

Customer orientation relates not only to maintaining the current range of services, but also to fulfilling latent customer expectations. The best way to inspire customers is to surprise them again and again with customer benefit innovations. "Quality Function Deployment" (QFD) is a method that is suitable as a supporting tool for the further development of products, but also services. The basis of QFD is the translation of customer requirements into specifiable quality features of a product or service. Although the procedure for service QFD in the service sector should not only be adapted individually to the company, but also to the respective area, all essential core elements of the QFD method with the associated process steps must be taken into account. The following 14 points are defined as corresponding key steps for the implementation of service QFD processes (see figure):

  1. Input: Cross-divisional search for innovative ideas and identification of the needs for the development of services
  2. Definition of the known and latent customer requirements for the service
  3. Evaluation of the importance of individual requirements by the customer
  4. Determining which customer requirements constitute a USP
  5. Determination of the degree of fulfillment and the target value for the individual requirements
  6. Ranking of customer requirements according to the potential chances in improving the degree of fulfillment
  7. Determination of the quality features / process steps of the service that can influence the achievement of the target values
  8. Determination of the correlation between customer requirements and quality features
  9. Determination of the target values ​​for the quality features / process steps
  10. Ranking of the quality features according to importance
  11. Selection of the most important quality features and customer requirements to be met for the creative workshop
  12. Implementation of the creative workshop - search for ideas for improving the service
  13. Evaluation of the ideas
  14. Output: test and implementation phase (14.1 review of feasibility and usefulness; 14.2 implementation of improvements and evaluation of effectiveness)

Service QFD project

was essentially based on the implementation of the following four workshops, in which the entire Service QFD team is involved, but in different compositions for each workshop:

  1. Workshop to determine customer requirements. In this first workshop, the service QFD team should first be informed about the exact procedure. Then the questionnaire for collecting customer requirements should be developed. Following the workshop, the questionnaires must be sent to a selected target group among existing and potential new customers. Finally, the results of the customer survey were evaluated.
  2. Workshop for the creation and elaboration of the "House of Quality". In the course of this second workshop, the fulfillment of customer requirements in comparison to the competition is to be determined, the concrete plan values ​​defined for the future, the quality characteristics of the service determined, the relationships between customer requirements and quality characteristics derived and the target values ​​for the quality characteristics of the service defined.
  3. Creative workshop to develop ideas for improvement. During the third workshop, the quality features should be precisely specified and ideas for the further development of the service collected.
  4. Strategy workshop with the management. This last workshop is used to evaluate the collected ideas for improvement based on the results of the Service QFD project, as well as to jointly make decisions about which of the collected and evaluated ideas should be implemented in the future in the form of service developments and customer benefit innovations.

literature

  • Yoji Akao : QFD-Quality Function Deployment. Verlag Moderne Industrie, Landsberg / Lech 1992, ISBN 3-478-91020-6 .
  • Georg Herzwurm, Sixten Schockert, Werner Mellis: Joint Requirements Engineering. QFD for Rapid Customer Focused Software and Internet Development. Vieweg et al., Braunschweig et al. 2000, ISBN 3-528-05736-X ( Vieweg Business Computing ).
  • Bob King: Better Design in Half the Time. Implementing Qfd Quality Function Deployment in America. 3. Edition. GOAL / QPC, Methuen MA 1989, ISBN 1-879364-01-8 .
  • Stuart Pugh: Concept selection - a method that works. In: Proceedings of ICED. 1981, ZDB -ID 51854-2 , pp. 497-506.
  • Magnus Richter, Haiko Schlink, Rainer Souren: Market-oriented product development using House of Quality, Conjoint Analysis and Target Costing - a case study using the example of digital SLR cameras. In: Ilmenauer Schriften zur Betriebswirtschaftslehre 3/2016, Ilmenau 2016.
  • Jutta Saatweber : Customer orientation through Quality Function Deployment. Systematic development of products and services. 2nd revised edition. symposium Verlag, Düsseldorf 2007, ISBN 978-3-936608-77-9 .
  • Genichi Taguchi : Introduction to Quality Engineering. Designing Quality into Products and Processes. Asian Productivity Organization, Tokyo 1986, ISBN 92-833-1083-7 .
  • John Terninko: Step by Step. Customer Driven Product Design. A Work Book to learn Quality Function Deployment (QFD). Responsible Management Inc., Nottingham NH 1995, ISBN 1-88238-210-2 .
  • Stefan Zischka: Targeted quality planning in product development. Project-specific quality deployment. Shaker Verlag, Aachen 2000, ISBN 3-8265-5951-7 ( Hanover reports on quality management 5), (At the same time: Hanover, Univ., Diss., 2000).
  • Emil Jovanov: Service-QFD: With Quality Function Deployment for innovative services 1st edition, Symposion Publishing, Düsseldorf 2011, ISBN 978-3-86329-421-2
  • Holger Brüggemann, Peik Bremer: Basics of quality management. From tools to methods to TQM. Springer Vieweg, Wiesbaden 2012, ISBN 978-3-8348-1309-1 .
  • Christine Knorr, Arno Friedrich: QFD - Quality Function Deployment. Systematically to market attractive products . 1st edition. Carl Hanser Verlag , 2016, ISBN 978-3-446-44804-9 .

Web links

  • QFD Institute Germany eV (QFD-ID) - Non-profit association for the promotion, dissemination and further development of QFD
  • QZ-online.de - QZ-online.de portal for quality management is a project in the media network of the trade journal QZ.