In my last post I demonstrated how to construct an Interference Diagram as well as creating a pie chart to summarize our finished results. In this post we will continue our analysis and complete our discussion on the Interference Diagram.
So, if we want
more Machine Output what can we do with the information in this analysis. The question to ask is this: “Are there any of these "interferences" that
the operator can stop doing to free up more time on the machine? “Any
interference you stop doing will free up more time to generate more machine
output. If you look you’ll notice that
lunch and break time is not something that will go away, nor should it. However, you might consider a person to run
the machine while the operator is on lunch and breaks. Not everyone needs to take lunch and breaks
at the same time. A staggered schedule
could free up a person to operate the machine.
This simple solution could gain and hour of production time.
There are other
possibilities to consider. What about moving
jobs into and out of the work area?
Should the operator be the person doing that? Perhaps, this could be off-loaded to someone
else and the operator could spend more time at the machine. In this case, it would be worth and
additional 9% increase in machine time. Also, what about looking for
paperwork? Maybe the paperwork needs to show
up when the job does so the operators don’t have to look for it. If it did, that’s another 19% increase in
machine time. By removing or reducing
just three of the interferences it is possible to increase machine output by
28%.
The Interference
Diagram is a great tool to find and exploit the hidden capacity of a constraint
operation. In this example it’s a tool to help you analyze how you can get more
from the constraint. To verbalize out
what those things are that the constraint could, or should, stop doing to free
up more time to do what you want more of.
OK, so now that
you’ve identified the interferences for more output, what’s next? Many times simple fixes work very well, so
let’s see how many simple fixes we can come up with and their impact on these
obvious examples of waste. To refresh
your memory, here is the completed ID.
What’s a simple
solution for interference #1, Looking for Paperwork? What if we didn’t consider the job ready to
work until all of the paperwork was assembled by someone else. Couldn’t we eliminate all 1.5 hours of
searching? How about interference # 2,
looking for parts? What if we
implemented a “full kit checklist” to be assembled by someone other than the
machine operator? In other words, the
job isn’t moved into the work area until all of the parts, paperwork and
special tools from supply were gathered up and sent to the work area as part of the next
job. Wouldn’t that eliminate
interferences 1, 2 and 7, effectively eliminating 90 plus 50 plus 20 minutes of
wasted time? Think about it, 160 more
minutes of capacity without spending any money.
How about
interference #4, looking for the supervisor?
What if a visual indicator system such as andon lights were installed to
notify the supervisor of a need at the work station? Green would be seen as no
problems, yellow might mean that the operator has a pending need and red might
mean that the work area is shut down until the need is taken care of. This kind of system wouldn’t eliminate all of
the time, but let’s say 20 of the 45 minutes? Simple solution to gain an
additional 20 minutes.
Finally, the movement
of jobs in and out of the work area, interference #’s 5 and 6. Just by using the andon lights (yellow) that
we already installed, someone else could be used to position new jobs and move
completed jobs. Again, you might not eliminate all of the wasted time, but
let’s say you were able to eliminate half of it or 23 minutes. So in this
example, implementing simple solutions, we might be able to eliminate roughly
203 minutes which could all be used to produce more output.
In my next post, we will begin a new blog post series on a completely new subject.
Bob Sproull
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