Group 3 Poka Yoke
-
Upload
ruchika-jangid -
Category
Documents
-
view
248 -
download
0
Transcript of Group 3 Poka Yoke
-
8/7/2019 Group 3 Poka Yoke
1/25
PresentationOn
Poka Yoke
Presented by:
Group 3
1
-
8/7/2019 Group 3 Poka Yoke
2/25
A common mistake of people who try to makethingscompletely fool-proof is to underestimate
the ingenuity ofcomplete fools.
-- DouglasAdams
2
-
8/7/2019 Group 3 Poka Yoke
3/25
` Shigeo Shingo invented the Japanese concept calledPoka-Yoke (pronounced POH-kah YOH-kay)
` The term "poka-yoke" comes from the Japanese words"poka" (inadvertent mistake) and "yoke" (prevent).
` Poka-Yoke means to mistake proof the process
The essential idea of poka-yoke is to design yourprocess so that mistakes are impossible or at least
easily detected andcorrected
3
Background and istory
-
8/7/2019 Group 3 Poka Yoke
4/25
4
` Apoka-yoke device is any mechanism that eitherprevents a mistake from being made or makes themistake obvious at a glance
` AsShingo writes, "Thecauses of defects lie in workererrors, and defects are the results of neglecting thoseerrors. It follows that mistakes will not turn intodefects if worker errors are discovered and eliminatedbeforehand
-
8/7/2019 Group 3 Poka Yoke
5/25
` The main objective of poke yoke is to achieve zero defects
` Poka yoke devices should have the followingcharacteristics: useable by all workers
simple to install
does not requirecontinuous attention from the operator (ideally, it should
work even if the operator is not aware of it)
low-cost
provides instantaneous feedback, prevention, orcorrection
5
-
8/7/2019 Group 3 Poka Yoke
6/25
6
-
8/7/2019 Group 3 Poka Yoke
7/25
` Forgetfulness
` Misunderstanding
` Wrong identification
` Lack of experience
` Willful (ignoring rules or procedure)
` Inadvertent or sloppiness
` Slowliness
` Lack of standardization
` Surprise (unexpected machine operation, etc.)
` Intentional (sabotage)
7
-
8/7/2019 Group 3 Poka Yoke
8/25
8
-
8/7/2019 Group 3 Poka Yoke
9/25
` Poka-yoke devices fall into two majorcategories:
Prevention
Detection
` A prevention device engineers the process so that it isimpossible to make a mistake at all
9
-
8/7/2019 Group 3 Poka Yoke
10/25
Example of Prevention Category
3.5 inch diskettecannot be inserted unless diskette is orientedcorrectly. Thisis as far as a disk can be inserted upside-down. The beveledcorner of the
diskette pushes a stop in the disk drive out of the way allowing the diskette
to be inserted. This feature, along with the fact that the diskette is not
square, prohibit incorre
ct orientation. 10
-
8/7/2019 Group 3 Poka Yoke
11/25
` A detection device signals the user when a
mistake has been made, so that the user can
quickly
corre
ct the problem
11
Detection Category
-
8/7/2019 Group 3 Poka Yoke
12/25
Incorrect Correct
Example 1
12
-
8/7/2019 Group 3 Poka Yoke
13/25
All internal lever are not
positioned properly so theother lever cannot be
locked.
All internal lever are
positioned properly so
outer lever can be
locked.
Example 2
13
-
8/7/2019 Group 3 Poka Yoke
14/25
Example 3
Incorrect Correct
14
-
8/7/2019 Group 3 Poka Yoke
15/25
Example 4
15
-
8/7/2019 Group 3 Poka Yoke
16/25
Error: putting a tube into a
patients stomach which was
intended for their lungs.
Example 5
16
-
8/7/2019 Group 3 Poka Yoke
17/25
Graphical user interfaces are all about mistake proofing. Remember
the DOS error message: Bad Command or File Name? It can't
happen when you point and click from a list.
Example 6
DOS- Character User Interface Windows - Graphical User Interface
17
-
8/7/2019 Group 3 Poka Yoke
18/25
Example 7Overlapping doors are used as
firedoors. The problem is that they
can be closed incorrectly.
This lovely mistake proofing device from
Wales solved the problem...
By proping the outter door open enough to
allow the inner door to swing past
before closing completely. You cannot close
the door wrongly.
18
-
8/7/2019 Group 3 Poka Yoke
19/25
Example 8This airport luggage cart has
brakes which are applied
whenever the yellow handle isnot depressed. Carts will not roll
unless they are attended. When
carts nested, the rear wheels of
all but the lastcart are wedgedoff the floor, so thecartscan be
pushed easily by airport staff
returning them to service areas.
19
-
8/7/2019 Group 3 Poka Yoke
20/25
Automatic light switch
in kids' bathroom
turns light on
automatically. Afterthe bathroom has
been unoccupied for
a few minutes, the
light goes off
automatically. The
error of forgetting toturn off the light is
eliminated.
Example 9
20
-
8/7/2019 Group 3 Poka Yoke
21/25
Stove A
Stove B
In A it is difficult to tell
which knob turns on
which burner?
B is Right. Because there is a natural
one-to-one mapping. Here the point is
that a little attention to detail, not a big
change, can make a huge impact onour ability to use the system
Example 10
21
-
8/7/2019 Group 3 Poka Yoke
22/25
Whose signature is required?
Before:
After:
Example 11 (I)
22
-
8/7/2019 Group 3 Poka Yoke
23/25
Here is an example of a form.
Before: We have all of these people who are supposed to
sign the engineering change notice and one really have to
thinkcarefully about who have to sign it.
After: We have a grid. The grid now says what type of
changes occurred, and has blanked out the unnecessary
signatures. So, now the form actually walks you through theapproval process so that youcan determine how to get the job
done.
Example 11 (II)
23
-
8/7/2019 Group 3 Poka Yoke
24/25
` Eliminate unnecessary or duplicate steps
Use flow charts to visualize the process
` Keep it simple
You dont have to spend a lot of money
` Use many Poka-Yoke devices in a process
There isnt a quota on how many you can use
24
-
8/7/2019 Group 3 Poka Yoke
25/25
` Poka-Yoke means to mistake proof the process
Remove the opportunity for error
x Improve the process
x Make wrong actions more difficult
If you cant remove the opportunity for error
x Make it easier to discover the errors that do occur
25