8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
1/23
TQE
VII
John R. Grout October 31, 1995
Towards Achieving Zero-Defect Quality:
Mistake-Proofing
John R. Grout, Cox School of Business
Southern Methodist University
ASQC: Texas Quality Expo
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
2/23
TQE
VII
John R. Grout October 31, 1995
If you like a copy of what you see here
or would like additional information:
Leave your business card with a note
Pick up my card and call, fax, or write Email to [email protected]
Visit the World Wide Web site
http://www.cox.smu.edu/jgrout/tqe.htmlhttp://www.cox.smu.edu/jgrout/pokayoke.html
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
3/23
TQE
VII
John R. Grout October 31, 1995
What will Quality be in the
year 2000? It will continue to be defined by the customer
It will be less of a competitive advantage
I
t will be more taken for granted (expected) It will require informed use of existing
quality tools
It will require more cost effective
improvements & solutions
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
4/23
TQE
VII
John R. Grout October 31, 1995
What causes defects?
Cultural factors
Variance Complexity
Mistakes
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
5/23
TQE
VII
John R. Grout October 31, 1995
What tools are used to achieve
zero defects? Cultural factors:
Teams, Driving out fear, management commitment
Variance SPC, Taguchi & DOE,
Complexity Process Mapping, DFMA
Mistakes Mistake-proofing, Poka-Yoke, or ZQC
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
6/23
TQE
VII
John R. Grout October 31, 1995
Motorolasfindings about Cp >2
...it became evident early in the project thatachieving a Cp greater than 2 would go only
part of the way. Mistake-proofing the designwould also be required ... Mistake-proofingthe design is an essential factor in achievingthe [total number of defects per unit] goal.
Smith, B. IEEE Spectrum 30(9) 43-47
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
7/23
TQE
VII
John R. Grout October 31, 1995
Evidence of the Effectiveness
of Mistake-proofing
Source: Productivity Inc. and Shingo prize profiles
AT&T Power Systems is first USmanufacturer to win the Deming prize.Average outgoing defects reduced by 70%
A washing machine drain pipe assembly lineproduced 180,000 units without a singledefect (6 months).
TRW reduced customer PPMs from 288 to 2.
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
8/23
TQE
VII
John R. Grout October 31, 1995
Mistakes: to err is human
Have you ever done the following:
Driven to work and not rememberedit?
Driven from work to home when youmeant to stop at a store?
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
9/23
TQE
VII
John R. Grout October 31, 1995
It happens to workers too.
Workers finish the shift and dontremember what they have done.
After building green widgets allmorning, the workers put green partson the red widgets in the afternoon.
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
10/23
TQE
VII
John R. Grout October 31, 1995
You have two options:
Demand vigilance. Exhort workers to
be more careful!
Mistake-proof. Eliminate the chance of
making the mistake
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
11/23
TQE
VII
John R. Grout October 31, 1995
A New Attitude towardPreventing Errors
Think of an objects user as attemptingto do a task, getting there by imperfect
approximations. Dont think of the useras making errors; think of the actions asapproximations of what is desired.*
*Source: The Design of Everyday Things, by D.A. Norman, 1988, Doubleday
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
12/23
TQE
VII
John R. Grout October 31, 1995
A New Attitude towardPreventing Errors
Make wrong actions more difficult
Make it possible to reverse actions to
undo themor make it harder to do whatcannot be reversed.
Make it easier to discover the errors thatoccur.
Make incorrect actions correct.
*Source: The Design of Everyday Things, by D.A. Norman, 1988, Doubleday
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
13/23
TQE
VII
John R. Grout October 31, 1995
What would YOU do?GM welding machine
A) Make a worker responsible for it
B) Track the proportion of missing nuts on achart
C) Increase preventative maintenance
D) Make the machine stop when the isnt
presentE) Change the fasteners to a clip-in device
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
14/23
TQE
VII
John R. Grout October 31, 1995
What would YOU do?L
HotelL
ouis XI
VA) Hire a floor manager who can unlock
doors when needed
B) Rent only half the rooms in the hotel
C) Tear down and build new building with abathroom for every room
D) Use a leather strap to keep both doors
closedE) Use electric door locks like a car
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
15/23
TQE
VII
John R. Grout October 31, 1995
What would YOU do?Nissan Stanza Van
A) Put a warning label on the fuel door and thesliding door
B) Reinforce the fuel pipe to withstand impact
C) Create a locking system that must beactivated in order to take the gas cap offwhich keeps the sliding door from opening
D) Move the fuel door etc. out of the way of thesliding door (e.g. to the other side)
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
16/23
TQE
VII
John R. Grout October 31, 1995
Approaches to
Mistake-Proofing
Source: Yoshikazu Tsuda, in Quality through Engineering Design (ed. Kuo) 1993.
Mistake prevention in the workenvironment
Mistake detection (Self-checks)
Mistake prevention (Source inspection)
Prevention of the influence of mistakes
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
17/23
TQE
VII
John R. Grout October 31, 1995
Examples of Mistake-Proofing
3.5 diskette
Binney and Smith
Trinity Industries Automobiles
Computer Software
Mail-order computer
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
18/23
TQE
VII
John R. Grout October 31, 1995
Where Mistake-ProofingWorks Well
1. manual operations where worker vigilanceis needed
2. where mispositioning can occur.
3. where adjustment is required
4. where teams need common-sense tools andnot another buzz-word.
5. where SPC is difficult to apply orapparently ineffective.
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
19/23
TQE
VII
John R. Grout October 31, 1995
Where Mistake-ProofingWorks Well
6. where attributes not measurements are important.
7. where training cost and employee turnover arehigh.
8. where mixed model production occurs.9. where customers make mistakes and blame the
service provider.
10. where special causes can reoccur.11. where external failure costs dramatically exceedinternal failure costs.
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
20/23
TQE
VII
John R. Grout October 31, 1995
Where Mistake-Proofingdoes NOT work well
1. Destructive tests.
2. Production rate is very fast.
3. Shifts occur more rapidly than they canbe responded to.
4. Self-checks when control charts are
used effectively.
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
21/23
TQE
VII
John R. Grout October 31, 1995
Shingo Shigeo :
Defects = is
absolutely possible!
John Grout:
If Defects = is possible,
Mistake-proofing will be in thetoolbox of those who achieve it.
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
22/23
TQE
VII
John R. Grout October 31, 1995
Lets not wait 30 years...
John P. Lafferty wrote:
Shingo brought his Poka-Yoke devices toAmerica in the mid-80s...Unfortunately, thereception to Shingos methods in this countryis similar to our response to Dr. W. EdwardsDeming in the 50s. It took us 30 years tobecome convinced Deming was right aboutstatistical control. Must we wait 30 more tobelieve Shingo?
8/4/2019 Towards Achieving Zero Defect Quality 1225713411606560 9
23/23
TQE
VII
John R. Grout October 31, 1995
Thank You!
Top Related