Quality Function Deployment (QFD)

ABSTRACT

This assignment presents a literature review of quality function deployment (QFD) based on a reference QFD publications established through searching various sources. The origination and historical development of QFD, especially in Japan and the US, are briefly accounted first, followed by a partial list of QFD organizations, software, and online resources. Then a categorical analysis is conducted about QFD’s functional fields, applied industries and methodological development. Ten informative QFD publications are also suggested, particularly for those who are not yet familiar with QFD. It is hoped that the assignment can serve the needs of researchers and practitioners for easy references of QFD studies and applications, and hence promote QFD’s future development.

Keywords;

Quality management; Product development; Customer needs; Quality function deployment (QFD)

1. INTRODUCTION

Quality function deployment (QFD) is “an overall concept that provides a means of translating customer requirements into the appropriate technical requirements for each stage of product development and production (example in; marketing strategies, planning, product design and engineering, prototype evaluation, production process development, production, sales)” (Sullivan, 1986). Since its initial development in Japan in the late 1960s and early 1970s, especially since its rapidly spreading to the US in the 1980s and later to many industries in many nations, a vast literature on QFD has evolved. To suit the different needs of QFD researchers and practitioners, its literature needs categorizing and reviewing. This is a meaningful but difficult work that seems having not been done yet.Although our literature search is admittedly incomplete, we believe that it covers a reasonable portion of QFD publications and thus is a useful source for QFD researchers and practitioners.

In this assignment, we try to conduct a literature review of QFD based on the above-mentioned reference. We first give a brief historical review of QFD with emphases on its origination and its development in Japan. A number of QFD organizations, software, and online resources are also listed for references. Then we present a categorical analysis of QFD applications in terms of purposes and where it has been applied to industries. We then proceed to review the methodological development of QFD, including quantitative methods applicable to it and its extensions and implementation issues. It is hoped that this assignment can serve the needs of interested readers for references of QFD studies and applications, and hence promote the future development of QFD.

2. A BRIEF REVIEW OF QFD’S HISTORY

2.1. Origination of QFD

In the Foreword for J. Terninko’s book Step by Step QFD (Terninko, 1997), B. King wrote,

“In the 1960s, Quality Control and Quality Improvement had a distinctively manufacturing flavor in Japan. In the late 1960s and early 1970s, Joji, (Yoji)Akao and others went to work on improving the design process so that when the new product was introduced to manufacturing, it was high quality from the beginning. The process for improving design was called Quality Function Deployment (QFD). From 1975 to 1995, this tool (process) was integrated with other improvement tools to generate a mosaic of opportunities for product developers.”

In Chapter 21, Quality Function Deployment, of the second edition of Gower Handbook of Quality Management edited by D. Lock, (Hill 1994) wrote similarly,

“QFD evolved from a number of different initiatives between 1967 and 1972, but the two main drivers which led to its creation in Japan were those:”

To improve the ‘quality of design’.

To provide manufacturing and field staff with the planned quality control chart (showing the points to be controlled within the production process) before the initial production run.”

Therefore, it is clear that “it was the struggle by product designers under the total quality control movement to improve their work that spawned quality function deployment in Japan” (Neff, 1991).

2.2. Development of QFD in Japan

Historically, Japanese industry began to formalize the QFD concepts when Mr. Oshiumi of the Kurume Mant plant of Bridgestone Tire produced a processing assurance chart containing some of QFD’s main characteristics in 1966 and K. Ishihara developed the ideas of “functional deployment of business” similar to those of QFD and applied them to Matsushita in the late 1960s (Cohen, 1995; Hill, 1994; Marsh et al., 1991).However, it was Akao who first realized the value of this approach in 1969 and wanted to utilize its power during the product design stage so that the product design characteristics could be converted into precise quality control points in the manufacturing quality control chart (Hill, 1994).After several industrial trials, Akao wrote a paper on this new approach in 1972 and called it hinshitsutenkai (quality deployment). This paper and Nishimura (1972) were the first two papers fostering the then new concept of QFD known to the West.

In the meantime, the Kobe Dockyard of Mitsubishi Heavy Industries began to apply the ideas of QFD in 1971 following Akao’s suggestion (Pardee, 1996),and Nishimura at Kobe produced a quality table that showed the correlation between the customer-required quality functions and the counterpart engineering characteristics between 1972 and 1974 (Hill, 1994; Nishimura, 1972).Akao formulated all these into a procedure channeling the customer requirements from the design stages down to the production operations, which was calledhinshitsukinotenkai (quality function deployment) (Cohen, 1995; Hauser and Clausing, 1988; Hill, 1994;Marsh et al., 1991; Prasad, 1998; Sullivan, 1986). QFD was introduced to Toyota’s Hino Motor in 1975 and Toyota Auto body in 1977 with impressive results, and was later introduced into the whole Toyota group.

A Japanese book on QFD edited by Mizuno and Akao, Deployment of the Quality Function, was published in 1978, showing the fast development and wide applications of QFD in Japan. Two years later, Kayaba won the Deming Prize with special recognition for applying QFD to bottleneck engineering (Cohen, 1995; Marsh et al., 1991).

Through the above-described explorations and practices, QFD has been successfully used in many Japanese industries, such as agriculture systems, construction equipment, consumer electronics, home appliances, integrated circuits, software systems, steel, synthetic rubber, and textile.

3. FUNCTIONAL FIELDS OF QFD

QFD was originally proposed, through collecting and analyzing the voice of the customer, to develop products with higher quality to meet or surpass customer’s needs. There are many approaches to QFD. Almost everyone agrees that for QFD to be successfully implemented within an organization. One of the approaches called The Four (4)-Phase approach.

QFD methodology flow: 4-Phase Approach

Product Planning

Part Deployment

Process Planning

Process/ Quality Control

4. FOUR (4) - PHASE APPROACH AND HOUSE OF QUALITY

A four phase approach is accomplished by using a series of matrices. Each phase has a matrix consisting of a vertical column of “Whats” and a horizontal row of “Hows”. Both legends of column and rows shows that “Whats” are Customer Requirements, meanwhile “Hows” are ways of achieving them.At each stage, the “Hows” are carried to the next phase as “Whats”

Figure 1: House of Quality Series

1ST PHASE: PRODUCT PLANNING

HOUSE OF QUALITY

The first phase in the implementation of the Quality Function Deployment process involves putting together a "House of Quality" (Hauser and Clausing, 1988) such as the one shown below, which is for the development of a climbing harness (fig. from Lowe & Ridgway, 2001).

Figure 2: Expanded House of Quality: Terminology and Conventions

Figure 3: Steps to the House of Quality (Becker & Associates, 2000)

Define Customer requirements

The first step in a QFD project is to determine what market segments will be analyzed during the process and to identify who the customers are. The team then gathers information from customers on the requirements they have for the product or service. In order to organize and evaluate this data, the team uses simple quality tools like Affinity Diagrams or Tree Diagrams.

Figure 4: Affinity Diagrams

Quantify Customer Requirements

Not all product or service requirements are known to the customer, so the team must document requirements that are dictated by management or regulatory standards that the product must adhere to.

Table 1: Quantify Table Requirements

PLANNING MATRIX

Evaluate your planned product against competitive products.

Consider the current strengths and weaknesses against your competitors.

 Identify in what areas the competitors are better, equal or worse at.

Identify what should be done to the product to reach expectations.

Table 2: Planning Matrix

• Customer Satisfaction.

Existing products fulfilling specified requirements.

• Improvement Ratio = Planned Performance / Existing Performance

• Sales Point

Weight for marketability.

• Overall Weighting = (Importance Weighting) x (Improvement Ratio) X(Sales Point).

Table 3: Planning Matrix

TECHNICAL REQUIREMENTS

To better understand the competition, engineering then conducts a comparison of competitor technical descriptors. This process involves reverse engineering competitor products to determine specific values for competitor technical descriptors.

Identify Measurable Characteristics relate to Customer Requirements.

It may have more than one technical requirement to convey one customer requirement.

Table 4: Technical Requirements

INTERRELATIONSHIPS

Develop relationships between all customer requirements and product requirements.

Critical Question:

How significant is technical requirement A in satisfying customer requirement B?

Are there product requirements that don't relate to any customer needs?

Table 5: Interrelationships

Use symbols for strong, medium, weak and none relationships.

THE ROOF

Considers impact of technical requirements on each other

Feature to feature comparison.

Figure 5: The Roof

Critical Question:

Does improving one requirement cause a deterioration or improvement in another requirement?

TARGETS

Develop preliminary target values for product requirements

Analyze the matrix and finalize the product development strategy and product plans.

Results from previous steps:

Customer requirements

Prioritized customer requirements

Technical requirements

Correlated requirements

Feature interdependencies

Made up from three parts:

Technical priorities

Competitive benchmarks

Final Product Targets

Calculate technical priorities

Assign a weighting factor to relationship symbols

Multiply each interrelationship weighting by the overall weighting from the planning matrix.

Sum them to their own columns.

Table 6: Calculate Technical Priorities

Competitive Benchmarks

Matrix values are simply the measure of the technical requirement.
The goal is to determine the relative positions of existing products with regard to each of the identified technical requirements

Table 7: Competitive Benchmarks

Final Product Targets

Analyze the matrix and finalize the product development strategy and product plans.

Table 8: Final Product Targets

HOUSE OF QUALITY 

Figure 6: House of Quality

HOUSE OF QUALITY SUMMARY

Inputs:

Customer requirements

Technical requirements

Customer priorities

Market reality / competitive analysis

Organization’ s strengths & weaknesses

Outputs

Prioritized technical requirements

Measurable, testable goals

The main difference with the subsequent phases however, is that in Phase 2 the process becomes a translation of the voice of the engineer in to the voice of the part design specifications.

Then, in phase 3, the part design specifications get translated into the voice of manufacturing planning. And finally, in phase 4, the voice of manufacturing is translated into the voice of production planning.

SECOND PHASE: PART DEPLOYMENT

The product requirements or technical characteristics and the product specification serve as the basis for developing product concepts.

Product benchmarking, brainstorming, and research and development are sources for new product concepts.

Once concepts are developed, they are analyzed and evaluated (cost & trade) using the concept selection matrix.

Table 9: Product Benchmarking

Using the selected concept as a basis, develop a design layout, block diagram and/or a preliminary parts list. Determine critical subsystems, sub assemblies or parts.

Figure 7: Design Layout

Analyze the matrix and finalize the subsystem/subassembly/part deployment matrix. Determine required actions and areas of focus.

Finalize target values. Consider interactions, importance ratings and difficulty ratings.

Table 10: Finalize Values

THIRD PHASE: PROCESS PLANNING

Concept selection matrix can be used to evaluate different manufacturing process approaches and select the preferred approach.

Based on selected approach, the process planning matrix is prepared.

Important processes and tooling requirements can be identified to focus efforts to control, improve and upgrade processes and equipment

Table 11: Concept Selection Matrix

FOURTH PHASE: PROCESS / QUALITY CONTROL

Detailed planning related to process control, quality control, set -up, equipment maintenance and testing can be supported by process/quality control matrix.

The process steps developed in the process planning matrix are used as the basis for planning and defining specific process and quality control steps in this matrix.

Table 12: Process Planning Matrix

5. THE FOUR (4) – PHASE OF TRADITIONAL QFD

Figure 8: Phase of Traditional QFD

6. BENEFITS OF USING QFD

Products meet customer expectations better.

Improved design traceability.

Reduced lead times.

Reduced product cost.

Improved communication within organization and with customer

7. PROBLEMS AND DISADVANTAGES

When applying QFD do not underestimate the amount of work involved.

Extra time and resources early in the project. Management must be prepared for this, and not press for visible results too early.

The scope and objectives of the project must be agreed at the beginning.

Avoid trying to include too much detail. Too large a matrix results in too much data to analyze.

Avoid gathering perfect data. Avoid technical arrogance and the belief that company personnel know more than the customer.

Best results are usually obtained by using an independent QFD facilitator to control the QFD process, leaving the rest of the team free to concentrate on the product.

8. SUMMARY OF TOPIC

QFD is a systematic means of ensuring that customer requirements are accurately translated into relevant technical descriptors throughout each stage of product development.  Therefore, meeting or exceeding customer demands means more than just maintaining or improving product performance.  It means designing and manufacturing products that delight customers and fulfill their unarticulated desires.  Companies growing into the 21st century will be enterprises that foster the needed innovation to create new markets. Therefore, we can conclude QFD is:

Understanding customer requirements.

Quality  systems thinking + Psychology + Knowledge/Epistemology.

Maximizing Positive Quality That Ads Value.

Comprehensive Quality System forCustomer Satisfaction.

Strategy to Stay Ahead of The Game

Finally,  since  tool  is make  to  just  aid  people,  even  the most  fully  functional  and powerful QFD software cannot replace a bit of any creativity and team works. So the best strategy should be: take advantages of best minds first, then the best software.

9. REFERENCES

Bester Field, D.H. Total Quality Management, 2nd Ed. Upper Saddle River, New Jersey, Prentice               Hall, (1999)

Akao, Y., Ed. (1990). Quality Function Deployment, Productivity Press, Cambridge MA.

Hauser, J. R. and D. Clausing (1988). "The House of Quality," The Harvard Business Review.

Mizuno, S. and Y. Akao, ed. (1994). QFD: The Customer-Driven Approach to Quality Planning

Adams and Gavoor, (1990) R.M Adams, M.D GavoorQuality function deployment: Its promise    and reality Transactions of the 1990 ASQC Quality Congress, San Francisco, CA (1990),           pp. 33–38

Becker Associates Inc, http://www.becker-associates.com/thehouse.HTM and                http://www.becker-associates.com/qfdwhatis.htm 

Lowe, A.J. & Ridgway, K. Quality Function Deployment, University of Sheffield, and         Development, Asian Productivity Organization, Tokyo, Japan, available from Quality           Resources, One Water Street, White Plains NY.

Acord, (1997) T AcordThe importance of product designFurniture Design and Manufacturing, 69                (1) (1997), pp. 90–93

Reilly, Norman B, The Team based product development guidebook, ASQ Quality Press,               Milwaukee Wisconsin, 1999

Sullivan, L.P., 1986, "Quality Function Deployment", Quality Progress, June, pp 39-50.