McGraw-Hill - Briefcase Books - Design for Six Sigma.pdf - six sigma - niundzia

What is Design for

Six Sigma?

The best Six Sigma projects begin not inside the business

but outside it, focused on answering the question, how

can we make the customer more competitive?

—Jack Welch

at least the basics of Six Sigma. So, we can review briefly

before getting into Design for Six Sigma.

Six Sigma is a revolutionary business process geared toward

dramatically reducing organizational inefficiencies that trans-

lates into bottom-line profitability. It started in the 1980s at

Motorola; then, organizations such as GE, Allied Signal, and

Seagate worked with the initiative during the 1990s and made it

the most successful business initiative of the era.

Key to the Six Sigma methodology of the 1990s is a five-

step process—Define, Measure, Analyze, Improve, and Control

Six Sigma: The Basics

S ince you’re reading this book, you’re probably familiar with

Design for Six Sigma

(DMAIC). By systematically applying these steps (with the

appropriate tools), practitioners of this approach have been able

to save substantial dollars.

) is a

statistical term that measures standard deviation . In the context

of management, it’s used to measure defects in the outputs of a

process and show how far the process deviates from perfection.

(We’ll get into the statistics in later chapters.)

A one-sigma process produces 691462.5 defects per million

opportunities, which translates to a percentage of satisfactory

outputs of only 30.854%. That’s obviously really poor perform-

ance. If we have processes functioning at a three sigma level,

this means we’re producing 66807.2 errors per million opportu-

Sigma ( σ ) A term used in statistics to represent standard

deviation, an indicator of the degree of variation in a set of

measurements or a process. A one-sigma process produces

691462.5 defects per million opportunities—a percentage of satisfac-

tory outputs of only 30.854%.

Standard deviation A measure of the spread of data points in rela-

tion to the mean. It’s the most common measure of variation in a set

of data.

Six Sigma A philosophy of managing that focuses on eliminating

defects through practices that emphasize understanding, measuring,

and improving processes. It’s based on the statistical concept of six

sigma, measuring a process at only 3.4 defects per million opportuni-

ties (DPMO).

Defect A measurable characteristic of the process or its output that

is not within the acceptable customer limits, i.e., not conforming to

specifications.The sigma level of a process is calculated in terms of

defects per million opportunities (DPMO).

Six Sigma Defined and Explained

The basis of Six Sigma is measuring a process in terms of

defects. The statistical concept of six sigma means your

processes are working nearly perfectly, delivering only 3.4

defects per million opportunities (DPMO). As you know from

your experience with Six Sigma, Sigma (the Greek letter

What Is Design for Six Sigma?

Figure 1-1. DPMO at sigma levels

nities, delivering 93.319% satisfactory outputs. That’s much bet-

ter, but we’re still wasting money and disappointing our cus-

tomers.

Most organizations in the U.S. are operating at three to four

sigma quality levels. That means they could be losing up to

25% of their total revenue due to processes that deliver too

many defects—defects that take up time and effort to repair as

well as make customers unhappy.

It’s Only Words ....

Smart managers realize the impact of words. Be sensitive to

the possibility that the word “defects” may bother employ-

ees.You may prefer instead to use the word “nonconformance.” As

D.H. Stamatis writes in the preface to Six Sigma and Beyond: Foundations

of Excellent Performance (CRC Press, 2002):

“(We prefer the term nonconformance for legal reasons.The tradi-

tional verbiage has been defective.) A nonconformance is a deviation

from the requirement.”

Whether you use “defect” or “nonconformance” or any other

word, what matters is that you’re measuring things that are not right

with your products or services—without blaming people or making

them feel defensive.

Design for Six Sigma

A Goal—and a Process

The concept of Six Sigma is to eliminate defects. Six sigma is

the goal, but it’s less important than the objective of pursu-

ing continuing process improvement.

Sometimes the Six Sigma implementation team needs to set more

realistic goals, depending on customer requirements and expectations

and the complexity of the product or service. Smart managers know

that the six sigma quality level is an idea; what’s real is the focus on

identifying defects and eliminating their root causes.

The central idea of Six Sigma management is that if you

can measure the defects in a process, you can systematically

figure out ways to eliminate them, to approach a quality level of

zero defects.

The goal is to get the maximum return on your Six Sigma

investment by spreading it throughout your company, continu-

ing to train employees in the Six Sigma methodology and tools

to lead process improvement teams, and sustaining the expo-

nential gains you achieve by keeping it going.

But in addition to the expanding practice of the methodolo-

gy and dollars redirected to the bottom line, there’s another

dimension to consider. Six Sigma doesn’t exist in a vacuum;

while its principles remain constant, there’s an evolution of its

message that can take companies in exciting new directions.

Design for Six Sigma

We’re referring to the discipline known as Design for Six Sigma

(DFSS)—an approach to designing or redesigning product

and/or services to meet or exceed customer requirements and

expectations.

Robert G. Cooper states in Winning at New Products:

Accelerating the Process from Idea to Launch (Cambridge, MA:

Perseus Books, 2001, 3rd edition) that only about 60% of new

products launched are actually a success and that for every

seven new product ideas, only four make it to development—

and then only one succeeds. What’s wrong with this picture?

What Is Design for Six Sigma?

The new product cycle is

definitely not operating at

a six sigma level. In fact,

it’s closer to the average

four sigma quality level at

which many companies

operate today. Plus, even

as manufacturing problems

are corrected by deploying

Six Sigma methods, newly

developed products often

are the source of new

problems. So, an organization practicing the methodology in

various functional areas and attaining Six Sigma status may

well be far below that level in developing new products or serv-

ices.

Once you’ve mastered the essentials of Six Sigma, you may

well be ready for the essentials of DFSS, to carry that improve-

ment into the development and design of your new products.

DFSS is based on the notion that when you design Six Sigma

Prepare for the Elevator

It’s smart to have a 30-second explanation of DFSS, an “eleva-

tor” speech, to answer a question that people are likely to ask. Here’s

one proposed by Jim Parnella, Staff Statistician for Alcoa, Point

Comfort,TX:

Six Sigma is a disciplined, data-driven approach to process

improvement aimed at the near-elimination of defects from every

product, process, and transaction.The purpose of Six Sigma is to

gain breakthrough knowledge on how to improve processes to

do things better, faster, and at lower cost . It can be used to

improve every facet of business, from production, to human

resources, to order entry, to technical support. Six Sigma can be

used for any activity that is concerned with cost, timeliness, and

quality of results. Unlike previous quality improvement efforts, Six

Sigma is designed to provide tangible business results, cost sav-

ings that are directly traceable to the bottom line.

Design for Six Sigma

(DFSS) A systematic

methodology using tools,

training, and measurements to enable

the design of products, services, and

processes that meet customer expec-

tations at Six Sigma quality levels.

DFSS optimizes your design process

to achieve six sigma performance and

integrates characteristics of Six Sigma

at the outset of new product develop-

ment with a disciplined set of tools.

McGraw-Hill - Briefcase Books - Design for Six Sigma.pdf

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