Quality Function Deployment

BITS PilaniPilani Campus

Quality Function Deployment (Qfd)

BITS Pilani, Pilani Campus

Introduction

QFD Benefits

House of Quality (HOQ)

QFD Steps to build HOQ

Conclusion

Agenda

BITS Pilani, Pilani Campus

Quality Function Deployment (QFD) is an approach to design introduced in Japan in 1966 by Yoji Akao.

Definition: QFD is a very systematic and organized approach of taking customer needs and demands in the consideration when designing a new products and services or when improving existing products and services.

Introduction

BITS Pilani, Pilani Campus

• Customer driven• Reduces implementation time• Promotes teamwork• Provides documentation

QFD Benefits

BITS Pilani, Pilani Campus

Applying the QFD steps builds the house of quality.

House of Quality (HOQ)

WhoVs.What

What What vs. HowNowVs.What

WHO How

How Vs. How

How much

Now

BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

QFD Steps

• Customers can be internal or external to the company.

• For many products, the most important customers are the consumers, the people who will buy the product and tell other consumers about its quality (or lack thereof).

Step 1: Identify the customers: determine exactly WHO they are.

WhoVs.What

What What vs. HowNowVs.What

WHO How

How Vs. How

How much

Now

BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

QFD Steps

Step 2: Determine the customers’ requirements: WHAT do the customers want?

• Typically, as customer surveys show, the consumers want a product that works as it should, lasts along time, is easy to maintain, looks attractive, and has many features.

• Typically, the production customer wants a product that is easy to manufacture and assemble, uses available resources, uses standard parts and methods, uses existing facilities, and produces a minimum of scarps and rejected parts.

• Typically, the marketing/sales customer wants a product that meets consumers’ requirements; is easy to package, store, and transport; is attractive; and is suitable for display.

WhoVs.What

What What vs. How

NowVs.What

WHO How

How Vs. How

How much

Now

BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

QFD Steps

Step 3: Determine relative importance of the requirements: WHO versus WHAT

• Relative importance can be evaluated by generating a weighting factor for each requirement.

• Traditionally, the customers are asked to rate each requirement on a scale from 1 to 10.

• A better method, the fixed sum method, is to tell each customer that they have 100 points to distribute among the requirements.

WhoVs.What

What What vs. HowNowVs.What

WHO How

How Vs. How

How much

Now

BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

QFD Steps

Step 5: Generate engineering specifications: HOW will the customers’ requirements be met?

• Engineering specifications are the restatement of the design problem in terms of parameters that can be measured and have target values.

• Parameters are developed in this step and the target values for these parameters are developed in step 8.

WhoVs.What

What What vs. HowNowVs.What

WHO How

How Vs. How

How much

Now

BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

QFD Steps

Step 6: Relate customers’ requirements to engineering specifications: HOW to measure WHAT?

• This is the central part of HOQ.

Strong relationshipMedium relationshipWeak relationshipBlank = no relationship

WhoVs.What

What What vs. HowNowVs.What

WHO How

How Vs. How

How much

Now

BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

QFD Steps

Step 7: Set engineering targets: HOW MUCH is good enough?

Target values are used to evaluate the product’s ability to satisfy customers’ requirements.Two actions:1. To ascertain how the

competitors (step 4) meets the engineering specifications, and

2. To establish the targets for the new product.

WhoVs.What

What What vs. HowNowVs.What

WHO How

How Vs. How

How much

Now

BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

QFD Steps

Step 8: Identify relationships between engineering requirements: How are the HOWs dependent on each other?

Negative (-1)

Strong negative (-3)

Strong positive (9)

Positive (3)

Engineering specifications may be dependent on each other. It is best to realize these dependences early in the design process. Who

Vs.What

What What vs. HowNowVs.What

WHO How

How Vs. How

How much

Now

BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

A Reduced HOQ Form

Customer Requirements

Engineering Characteristics

Target values

Competitive assessment

Impo

rtan

ce ra

ting

Correlation matrix

Relationship matrix

BITS Pilani, Pilani Campus

• A Markov chain model is commonly used to study the short- and long-run behavior of certain stochastic systems

• Markov chain models assume that a system starts in an initial state but the initial state will be changed over time

• If the chain is currently in state si, then it moves to state sj at the next step with a probability denoted by pij, and this probability does not depend upon which states the chain was in before the current state.

MARKOV MODELING AND QFD

BITS Pilani, Pilani Campus

• The probability that the system is in each state j no longer depends on the initial state.

• APPLICATION OF MARKOV MODEL IN QFD• Let us consider that the customer requirements which have

been found out are denoted by CR and the technical measures are denoted as TM.

• The relationship between identified WHATs and HOWs can be STRONG (S), MEDIUM(M), WEAK(W) and NONE(N) each having their respective weights as s, m, w and zero respectively

STEADY STATE PROBABILITIES

BITS Pilani, Pilani Campus

• The relationship and importance of technical measures is obtained on a timely basis.

• It helps the decision makers in absence of much information and past experiences

Advantages of Markov Model in QFD

BITS Pilani, Pilani Campus

• The QFD technique ensures that the problem is well understood.

• The HOQ automatically documents and records the evolution of the product design.

• The HOQ is an excellent communication tool for the design team.

• The QFD technique can be applied at any of the design phases.

Conclusion