2. CONTENTS
2
INTRODUCTION
WHAT IS ERROR ?
POKA YOKE OVER ERRORS
IMPORTANCE
WHEN TO USE
HOW TO USE
METHODS
DAY 2 DAY EXAMPLES
3. WHAT IS POKA YOKE ???
3
a) Brother of PIKACHU
NO
b) A new Chinese action hero
It’s a mistake proofing
c) A disease
technique used by each of us
4. INTRODUCTION
4
Pronunciation POH-KAH-YOH-KAY
YOKERU Avoid
POKA Mistakes
Coined in Japan during the 1960s Shigeo
by as
Shingo
part of the Toyota Production System
5. INTRODUCTION (Cont.)
5
Initially „BAKA-YOKE‟ „fool-proofing‟
Dishonorable and offensive
Changed to „POKA-YOKE‟ „mistake-
proofing‟
6. WHAT IS ERROR ???
6
A mistake : deviation from what is correct, right, or true
How to prevent error
Old way Scold people
Retrain them
Tell them to be more careful…
New way Training and motivation
Easy way to do a job
The potential for human error can be dramatically
reduced
7. What Causes Defects?
7
Errors lead to defects
1. Poor procedures or standards
2. Machines
3. Non-conforming material
4. Worn tooling
5. Human Mistakes
9. Poka Yoke over Errors
9
Help operators avoid mistakes in their work caused by
choosing the wrong part, leaving out a part, installing a part
backwards, etc.
Involves the implementation of fail-safe ways methods that
detect or prevent human and machine error at or near the
source.
Provides instant feedback and prevention of quality problems
10. Poka-Yoke as a…
10
Poka Yoke as Prevention Device:
Examples: part locators, part present sensors.
Poka Yoke as Detection Device:
Examples: vision system, limit sensors
12. Why is it important?
12
Helps people and processes
Refers to techniques that make it impossible to make
mistakes.
Helps drive defects out of products and processes and
substantially improve quality and reliability.
13. Contd…
13
Used to fine tune improvements and process designs
from six-sigma.
Use the ideas and methods in product and process
design which can eliminate both human and mechanical
errors.
14. When to use it?
14
It is a technique, a tool that can be applied to any type of
process be it in manufacturing or the service industry.
Poka-yoke can be used wherever something can go
wrong or an error can be made.
15. Contd…
15
Errors can be of any type-
i. Processing Error: Process operation missed or not
performed per the SOP.
ii. Setup Error: Using the wrong tooling or setting
machine adjustments incorrectly.
iii. Missing Part: Not all parts included in the assembly,
welding, or other processes.
iv. Improper part/item: Wrong part used in the process.
v. Operations Error: Carrying out an operation incorrectly;
having the incorrect version of the specification.
vi. Measurement Error: Errors in machine adjustment, test
measurement or dimensions of a part coming in from a
supplier.
16. How to use it?
16
Step by step process in applying poka-yoke:
1. Identify the operation or process
2. Analyze the 5-Ws and understand the ways a process can
fail.
3. Decide the right Poka-yoke approach, such as using a,
Shut out Type: Preventing an error being made, or an
Attention Type: Highlighting that an error has been made.
17. Contd…
17
4. Determine whether a
Contact Method
Constant Number or Counting Method
Motion-Sequence Method
5. Trial the method and see if it works.
6. Train the operator, review performance and measure
success.
18. Methods in Detail
18
Contact Methods:-
“Do not have to be high tech!”
These can be as simple as blocks that do not
allow parts to be seated in the wrong position prior
to processing.
19. Methods in Detail
19
Take advantage of parts designed with an
uneven shape.
This method signals to the operator right away
that the part is not in proper position.
20. Methods in Detail
20
Constant Number or Counting Method:-
Used when a fixed number of operations are
required within a process.
When a product has a fixed number of parts that
are attached to it.
A sensor counts the number of times a part is
used or a process is completed and releases the
part only when the right count is reached.
21. Methods in Detail
21
Motion-Sequence Method:-
The third poka yoke method uses sensors to
determine if a motion or a step in a process
has occurred.
If the step has not occurred or has occurred
out of sequence, the sensor signals a timer or
other device to stop the machine and signal
the operator.
26. 26
Microwaves
Washing machines
Central locking in modern cars
Key locks in mobiles
Refrigerators
Beeps in automobiles if key is left in ignition
27. 27
Okay, So This Is Not An
Everyday Example For
Anybody. I Hope You'll Find It
Interesting …
28. Submarine
28
The bathyscaph is a deep water submarine used to explore the very lowest
parts of the ocean. It is electrically powered. Once at the bottom, if the
batteries or electrical system fail the best outcome would be for the sub to
return to the surface. The designers made this outcome occur by holding
the ballast in place with electromagnets. When power is lost, the ballast
drops off automatically and the sub starts its ascent.
29. Characteristics of PokaYoke
29
devices
Simple and cheap
Part of the process, permitting 100% inspection
Placed close to where the mistakes occur, providing quick
feedback
Designed to stop a particular mistake
A detection device cannot provide a complete error proof
solution
30. REMEMBER
30
TO ERR IS HUMAN NATURE
BUT
INTELLIGENCE IS ALSO HUMAN
NATURE
SO
NEVER STOP FINDING WAYS OF
NOT MAKING MISTAKES