Quality Function Deployment (qfd).pdf

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Quality Function Deployment (QFD) for Product Design Mr. Mahesh. J. Patil Assistant Professor, Production Engineering Department, Bharati Vidyapeeth University, College Of Engineering, Pune-411043. email: [email protected]

Abstract This Paper helps to understand the present Scenario of QFD in Industries. Quality Function Deployment enables the designers and planners to decide upon the product Design, after getting the voice of customer from the market and they can put large emphasis on the criteria's stated by the customer .The process gives rating to the design criteria's given by the customers and can help to identify the most important ones. Thus the Product manufactured is according to the customer requirements.

--.. Key words: Quality Function Deployment, Voice of Customer, House of 'Quality. Introduction:

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Quality function Deployment (QFD) is a planning tool used to fulfill customer exp~ctati09~: It is a disciplined approach to product development. An or~anizatiohtha~j ~on:¢riy implements QFD can improve engineering Knowledge, productivity and. qualityand reduce costs.. product development time and engineering changes. It focuses customer expectations or requirements, often referred to as. the voice of customer. It is employed to translate customer expectations, in terms of specific requirements, into directions and actions. Here Conflicting characteristics or requirements are identified early in the QFD process and can be resolved before production. QFD was initialized by Dr.Mizuno, professor emeritus of the Tokyo Institute of Technology. The first application of QFD was at Mitsubishi, Heavy Industries Ltd.,in Kobe Shipyard,Japan,in 1972.After case study development, refinement and training.QFD was successfully implemented in the production of mini Vans by Toyota. Using 1977 as a base, a 20% reduction in startup costs was reported in the launch of the new van in October 1979,a 38% reduction by November I982,and a cumulative 61% reduction by ApriI1984.Dr.Clausing of Xerox 'introduced QFD first in United States in 1984.1t can be pplied to any manufacturing and service industries.

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Voice of Customer: The QFD process reduces the overall cycle time in bringing the product to market. The driving force behind QFD is that the customer dictates the attributes of a productCustomer satisfaction like quality is defined as meeting or exceeding customer expectations. Words used by the customers to describe their expectations are often referred as the voice of the customer. Sources for determining customer expectations are focus groups, surveys complaints, consultants, standards and federal regulations.

Organisation of Information: The information being collected as the voice of customer requires to be organized properly.The various methods udes for the same are affinity diagram, interrelationship diagrams,tree diagrams and cause and effect diagrams.The affinity diagram is mostly used for QFD applications.

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Proceedings of 2nd National Conference TIME 2010

Affinity Diagram: The affinity diagram is a tool that gathers a large amount of data and subsequently organizes the data into groupings based on their natural interrelationships.These are to be used when thoughts are too widely dispersed. The Procedure affinity diagram is as follows: 1. Phrase the Objective. 2.· Record all responses. 3. Group all the responses. 4. Organize groups in an affinity diagram.

House of Quality: The primary planning tool used in QFD is the house of quality.The house of quality translates the voice of customer into design requirements that meet specific target values and matches those against how an organization will meet those requirements. The structure of QFD can be thought of as a framework of house. The parts of house are described below: • Exterior walls: Customer Requirements and prioritized customer requirements. • Interior walls: Relationship between customer requirements and technical descriptors or engineering Characteristics. • Roof: Interrelationship between technical descriptors. • Floor: Technical Descriptors. • Foundation: Prioritized technical descriptors.

Steps to Built the House of Quality: Step I-List Customer Requirements (Whats): The list of goals/objectives is often referred as the WHATs that a customer needs or expects in a particular product. They form the left side exterior wall of the house. The requirements can be categorized into primary, secondary and tertiary. The primary list is usually vague and very general in nature. Further definition is accomplished by defining a new, more detailed list of secondary customer requirements and if the details are not satisfied they are further rooted as tertiary. Step 2-List technical descriptors or engineering characteristics. (HOW): The goal of house of quality is to design or change the design of a product in a way that meets or exceeds the customer expectations. Now the roofforms the technical descriptors that talk about HOW the requirements are to be satisfied. The technical descriptors are Further subdivided into Primary, secondary and tertiary .The secondary and tertiary descriptors explain the primary descriptors in more details.This process is similar to refining marketing specifications into system-level engineering specifications. Step 3-Develop a Relationship Matrix.Between Whats and Hows. The inside or interior walls of the house are called the relationship matrix is filled next by the QFD team. The relationship matrix is used to represent graphically the degree of influence between each technical descriptor and each customer requirement.This step being done earlier in product development reduces development cycle.!t is common to use symbols to represent the degree of relationship between the customer requirements and technical descriptors.Later numerical values are also given.These weights will be used later for determining trade-off situations for conflicting characteristics and determining an absolute weight at the bottom of the matrix.

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Relationship A Solid Circle represents strong relationship.

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A Single Circle represents medium relationship. 3 0 /:). A triangle represents a weak relationship. I Blank Cell represents a no relationship --Table no.1 After relationship matrix has been completed ,it is evaluated for empty rows or columns.An empty row indicates customer requirement not been addressed by any of the technical descriptors and a empty column indicates that a particular technical descriptor does not affect any of the customer requirements and may be removed. Step 4-Develop an Interrelationship Matrix Between Hows: The roof of the house of quality, called the correlation matrix, is used to identify any interrelationships between each of the technical descriptors. The correlation matrix ia a triangular table attached to the technical descriptors. For evaluation purpose the symbols and values used are given in table no.2. Relationship A Solid Circle represents strong positive relationship.

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A Single Circle represents medium relationship. 0 A cross represents a negative relationship. X An asterisk represents a strong negative relationship * Table 00.2 The diagram allows the user to identify which technical descriptors which are in conflict.

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Step 5-Competitive Assessments: The competitive assessment is pair of weighted tables (or graphs) that depicts item how competitive products compare with current organization products. The competitive assessment tables are separated into two categories, customer assessment and technical assessment. • Customer competitive assessment: The customer competitive assessment makes up a block of columns corresponding to each customer requirement in the house of quality on the right side of the relationship matrix. The numbers 1 through 5 are listed in the competitive evaluation column to indicate a rating of 1 for worst and 5 for the best. • Technical competitive assessment. The technical competitive assessment makes up a block of rows corresponding to each technical descriptor in the house of quality beneath the relationship matrix. The products are evaluated for each technical descriptors.For evaluation purpose the test data are converted to the numbers I through 5,which are listed in the competitive evaluation row to indicate a rating, 1 for worst and 5 for best.

Department of Mechanical Engineering, PDEA's A. G. Awate College of Engineering, Hadapsar, Pune

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Proceedings of 2nd National Conference TIME 2010

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Step 6-Develop Prioritized Customer Requirements: The prioritized customer requirements make up a block of columns corresponding to each customer requirement in the house of quality on the right side of the customer competitive assessment.These prioritized customer requirements contain columns for importance to customer,target value,scale-up-factor,sales point and absolute weight .The Absolute weight is the product of importance to customer ,scale-up-factor and sales point. Step 7-Develop Prioritized Technical Descriptors: The prioritized technical descriptors make up a block of rows corresponding to each technical descriptors in the house of quality below technical competitive assessment. These prioritized technical descriptors contain degree of technical difficulty, target values and absolute and relative weights.The QFD team identifies technical descriptors that are most needed to fulfill customer requirements and need improvement.. The QFD matrix is the basis for all future matrices needed for the QFD methods. Although each house of quality chart now contains a large amount of information, it is still necessary to refine the technical descriptors further until an actionable level of detail is achived.Often more than one matrix will be needed depending on the complexity of the project.

Conclusion: In Quality function deployment ,the house of quality is an effective management tool in which customer expectations are used to drive the design process.Every QFD chart is a result of the original customer requirements that are not lost through misinterpretations or lack of communication

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References: 1.

Franceschinin, F. Galetto, M. and Ceaoni, P. (2006), "A world wide analysis of ISO 9000 standard diffusion': Considerations and future development", Benchmarking: An International Journal, Vol. I3 No.4, i=-p.523-54 I.

2.

Dijkstra, L. and Bij, H., (2002), "Quality Function Deployment in health care Methods for meeting Customer Requirements in Redesign and Renewal", International Journal of Quality &Reliability Management, Vol. 19No. I, pp. 67-89.

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Devadasan, S.R., Kathiravan, N. and Thirunavukkarasu, V., (2006), "Theory and practice of total quality function deployment: A perspective from a traditional pumpmanufacturing environment", The TQM Magazine, Vol. I8 No.2, pp.143-161.

4.

Akao, Y. and Mazur, G.A. (2003), "The leading edge in QFD: past, present and future", international Journal of Quality and Reliability Management, Vol. 20 No. I, pp.20-35.

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Dale H.Besterfield,Carol Besterfield "Total Quality Management" Second edition,Published by Addison Wesley Longman (Singapore)pte.Ltd.

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PDEA's A. G. Awate College of Engineering. Hadapsar. Pune

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