C.D.L.M Govt. Engg. College
The Taguchi Method:
THE SERVICE MANAGER’S PRIMER TO
QUALITY
Submitted to:Mr. Pawan Kamboj Sir
(Lect. In Mechanical Department)
Submitted by:Chetan Gosain
Roll No:-10512
Mech. Branch
4th Year/8th Sem
GENICHI TAGUCHI
• Born in Japan, 1924
• Electrical Engineer
• Worked during 1950’s to improve
Japan’s post-WWII telephone
communication system
• Father of the “Taguchi Method” and
“Robust Engineering”
Topics Covered
Dr. Genichi Taguchi
The Taguchi
Method
-Quality Loss Function
The Taguchi method
• Quality
• Robust Design
• Quality Loss Function
Don’t run away!
• Not a mathematician?
• You can still successfully apply
Taguchi Method concepts to your
service business.
• Basic concepts are simple.
• Just keep reading.
Competitive Edge 101:
• “In the next century, the capability of
developing robust technology will be
essential to the competitiveness of
any manufacturing enterprise.” (Tsai)
(Taguchi: p xi)
Competitive Edge 102:
• “To compete successfully in the
global marketplace,
organizations must have the
ability to produce a variety of
high-quality, low-cost products
that fully satisfy customers’
needs.” (Robust Engineering; p. xiii)
Quality Defined
• Ideal Quality
- reference point (target value) for
determining the quality level of
a product or service.
- delivery of a product or a service
that reliably performs it’s
intended use throughout it’s life
cycle under reasonable
conditions.
Robust Design
• “An Engineering methodology for
improving productivity during
research and development so that
high-quality products can be
produced quickly and at low cost”
(1).
• Products and services designed
defect free and of high quality
• A design with minimum sensitivity to
variations in uncontrollable factors.
Quality Loss
Function
• Defined
-economical and societal
penalties incurred as a result of
purchasing a nonconforming
product.
Determining
Quality Loss Function
• Specifications are set
• Specify a target with
minimal variation
• Increase in variation
cause loss to society
Set Specifications
• Loss to society
-Product rejection
-Product rework
-Pollution
Specify a target with
minimal variation
Specify a target with
minimal variation
• Disagreements with standard
quality
LSL- Lower specification limit
USL- Upper specification limit
Specify a target with
minimal variation
• Quadratic Loss Function
Why use Taguichi’s
Quality Loss Function?
1) To find out how much loss is
brought to Society due to a
purchase of a nonconforming
product.
2) To implement a product design
improvement.
How can we use Taguchi’s Quality
Loss Function in real life?
Let’s assume that you are an Operations Manager
at a company that produces custom made doors
and door frames. During the winter, due to cold
weather, doors tend to shrink which lets in cold air
through the cracks between the door and the door
frame. During the summer doors tend to expand
beyond it’s normal size due to hot weather, which
makes to door hard to open because it rubs against
the door frame. Your job is to produce a door,
where dimensions (length and width of the door)
are set to a specific target level. In other words in
the Winter the door cannot let any cold air in the
house and it should open properly in the Summer.
How can we use Taguchi’s Quality
Loss Function in real life?
18
How can we use Taguchi’s Quality
Loss Function in real life?
The picture shows the same kind of a door under different
weather conditions. The way to set a target at a specific
level, we must first calculate the dimensions of the door
under cold conditions and then during the hot conditions
(compared to conditions during the winter and the
summer). We then take the most cold temp. and add it to
the most hot temp.. We then take the answer and divide it
by two to get the average temp. We then place the door
under the average temp. to find our set dimensions. These
dimensions should be the best solution to a robust design.
Basic Ideas:
• CUSTOMER SATISFACTION
• Design to the highest standards
early in the process to eliminate all
non-random errors
• Quality Loss = Loss to Society
quantified through “Quality Loss
Function”
• Variation (+/-) from optimal measure
results in a loss.
Customer Satisfaction
• Ways to measure service:
1. Returning customers
2. Number of complaints (1:10)
3. Number of compliments
4. Employee attitude
Quality Loss Concept
• Deviation from
target results in
loss.
– Lower than
target
– Greater than
target
– Both lose
Quality Loss Function
• Quantify the Loss
• Warning:
Next slide contains
math formulas
• But give it a try!
Quality Loss Function II
L(y) = k(y-m)2
L(y) = Loss
k = constant =
cost to correct
tolerance2
y = reported value
m = mean value (average)
(Taguchi On Robust Technology p. 22)
Example:
• Company C received an average of 10
complaints per month last year. In
November they received 15 complaints (y).
Management sets an acceptable level at 2
(tolerance).
• It costs the company $50 directly per
complaint to correct the problems. They
determined the cost in lost sales to be
$100.
• Total cost per complaint: $150
Example continued:
k = $150/22 = $37.50
L(y)
= 37.50 (15-10)2
= 37.50 (5)2
= 37.50 (25)
= $937.50 is loss for the
month of November
MATH DONE!
Taguchi Experiment – Steps
According to Dr. Foster:
(OM Review p. 38-44)
• Managers’ job:
– Identify the Problems
– Brainstorm
– Contribute to experiment design
• Facilitator’s job:
–
–
–
–
Design experiment
Run experiment
Analyze results
Confirm experiment
Step 1:
Problem Identification
• What do managers and/or
employees see that need
improvement?
Step 2:
Brainstorming
• Identify critical variables in the
service that affect quality.
• Open and honest discourse with
all people involved.
• Decide which factors are
controllable and which are not.
Step 3:
Experiment Design
• Using results from brainstorming
session, facilitator will design
an experiment.
• Management must understand
this part, and needs to fully
support the resources needed
for it.
Step 4:
Experiment
• Use of ANOVA requires
managers understand its use.
• Facilitator, although in charge of
the experiment, must assure
management’s understanding of
the process.
Step 5:
Analysis
• Factors closest to target
specification identified.
• Means to reduce controllable
variation produced.
Step 6:
Confirm Experiment
• Set up new system using data
from experiment.
• Test and validate results.
Conclusion:
• Best improvement is early in the process.
• Use expert consulting help for full
experiment and implementation.
• Successfully used in airlines, insurance,
hotels and restaurants.
• Quality is a major feature that sets a
service apart from the rest.
Success Stories
• AT&T Bell Laboratories
(Computer Response-Time
Optimization).
• Chrysler Motors Engineering
(Sheet-Molded Compound
Process Improvement)
-finished products improved
from 77% to 96%.
-scrap was reduced from 16% to
1.7%.
Summary
• Companies design and produce
low-cost, highly reliable quality
products and processes.
• Cuts research, development,
and delivery time.
• Allows engineers to develop
flexible technology for the
design and production.
Bibliography
1)PRODUCT QUALITY MANAGEMENT BY
Frank Moisiadis
2)TAGUCHI APPROACH TO DESIGN OPTIMIZATION FOR
QUALITY AND COST Resit Unal & Edwin B. Dean
3)
DOE-IBasicDesign of Experiments
Presented By Nutek, Inc.
4) Introduction to Taguchi Method
Wekipedia.
THANK YOU