Chapter 17

Quality Function Deployment

Objectives

• After reading the chapter and reviewing the materials presented the students will be able to:

• Understand QFD (Quality Function Deployment).• Develop set of customer needs (WHATs)• Plan the improvement strategy• Select the technical requirements (HOWs)• Evaluate relationships between needs and requirements• Evaluate correlation between requirements• Select design targets (Values) of requirements

What is QFD?

• Quality function deployment (QFD) is a specialized method for making customer needs/wants important components of the design and production of the product or service.

• The purpose of QFD (Quality Function Deployment) is to identify customer needs and ensure that they are effectively accommodated in product design.

• One of the keys to achieving continual improvement is getting customers involved as early in the product development process as possible.

QFDs House of Quality

• The most widely used analogy for explaining how QFD is structured is a house of Quality (HOQ)(fig 17-1, page 297).

• The House of Quality uses a multifunctional team to take inputs from the customer and translate them into a set of customer needs known as the Voice of the Customer (VOC).

• The VOC and some benchmarking with competing products determines the prioritized features of the new (or improved) product or service that will respond to the VOC.

Structure of QFD• The most widely used analogy for explaining how QFD is structured is a house (fig

17-1, page 297).• The wall of the house on the left is customer input.• To meet customer requirements the manufacturer works to certain performance

specifications and requires the suppliers to do the same. This is the ceiling of the house.

• The wall of the house on the right is the planning matrix. The planning matrix is the component used to translate customer requirements into plans for meeting or exceeding those requirements.

• The middle of the house is where the customer requirements are converted into manufacturing terms.

• The floor of the house is where the manufacturer’s critical process requirements are prioritized.

• The roof of the house is where tradeoffs are identified.

QFD Process• Six matrices are developed in a complete cycle of the QFD process. The purpose of each matrix is as

follows:• Matrix 1 is used to compare customer requirements with the related technical features of the product. All

other matrices grow out of the first matrix.• Matrix 2 is used to compare the technical features of Matrix 1 with the related applied technologies. • Matrix 3 is used to compare the applied technologies from Matrix 2 with their related manufacturing

processes. This matrix helps identify critical variables in manufacturing processes.• Matrix 4 is used to compare the manufacturing process from Matrix 3 with their related quality control

processes. This matrix produces the information needed to optimize processes.• Matrix 5 is used to compare the quality control process with their related statistical process control

processes.• Matrix 6 is used to compare the statistical process control parameters with the specifications that have

been developed for the finished product. The QFD process ensures that all resources are being optimally used in ways that maximize the organizations chances of meeting or exceeding customer requirements.

Customer Information: Feedback and Input

• Customer information falls in two broad categories: feedback and input.

• Feedback is given after the fact. At best it can help improve the product when the next batch is produced.

• Input is obtained before the fact. Collecting customer input during product development allows changes to be made before producing, marketing, and distributing large quantities of a product. Collecting input is more valuable than collecting feedback.

Affinity Diagrams

• Affinity Diagrams are used to promote creative thinking (fig 17-2, page 299).

• Affinity diagrams are used when the issues are complex or the known facts are disorganized, and people cannot get their arms around the situation.

• They are also used when it is necessary to shake up the thought process and get past solutions that failed.

• Affinity diagrams can be used when it is important to build a consensus for a proposed solution.

• Cross functional teams typically have memberships from all relevant functional departments (sales, marketing, production, finance).

Sales Point• Sales point is a number from 1 to 1.5 that is used to place emphasis on

customer needs.• It is an estimate of the marketing importance of the need in promotion of

the new product.• A sales point of 1 results in no change in overall weighting.• A sales point of 1.5 increases the overall weighting.• This data is placed in the planning matrix.• Precision in Rating/Ranking Scale: The rating/ranking numbers are the

result of a lot of opinion and estimating all the way from the customer to the team deliberations and discussions. So the company should not allocate the work of improving the product or service solely by these numbers.

The HOQs Roof: Correlation Matrix

• As a product or service is being designed, there will inevitably be some technical requirements that tend to benefit one another and some that tend to work against one another.

• Getting it right the first time is the purpose of the Correlation Matrix or Roof of the HOQ.

• The correlation matrix is constructed by drawing a triangle (looking like a roof) over the technical requirements section of the HOQ (fig 19-7, page 306).

• A supportive relationship is indicated by a + sign at the intersection of the two technical requirements, a negative relationship is indicated by the use of a – sign.

• A blank indicated no significant correlation.

Design Targets

• The objective of design targets is to establish specific objectives for the design team.

• There will be situations in which one must consider a radical change that can achieve two opposing goals, such as reducing cost, and improving quality.

Summary• The purpose of QFD (Quality Function Deployment) is to identify customer needs and ensure that they are effectively

accommodated in product design.• QFD brings a number of benefits to organizations trying to enhance their competitiveness by continually improving quality

and productivity. The process has the benefits of being customer focused, time efficient, teamwork oriented, and document oriented.

• Customer information falls in two broad categories: feedback and input. Feedback is given after the fact. At best it can help improve the product when the next batch is produced. Input is obtained before the fact. Collecting customer input during product development allows changes to be made before producing, marketing, and distributing large quantities of a product. Collecting input is more valuable than collecting feedback.

• Affinity Diagrams are used to promote creative thinking.• Cross functional teams typically have memberships from all relevant functional departments (sales, marketing, production,

finance).• Sales point is a number from 1 to 1.5 that is used to place emphasis on customer needs.• Precision in Rating/Ranking Scale: The rating/ranking numbers are the result of a lot of a lot of opinion and estimating all

the way from the customer to the team deliberations and discussions. So the company should not allocate the work of improving the product or service solely by these numbers.

• As a product or service is being designed, there will inevitably be some technical requirements that tend to benefit one another and some that tend to work against one another. Getting it right the first time is the purpose of the Correlation Matrix or Roof of the HOQ.

• The objective of design targets is to establish specific objectives for the design team.

Home Work

• Answer Questions 1, 4 on page 311.• 1. Define Quality Function Deployment?• 4. List the benefits of QFD.