Quick Changeovers & SMED
6
Learning Objectives
At the completion of this unit the
participant will be able to:
1.
2.
3.
4.
5.
What are Quick Changeovers?
Why Quick Changeovers?
The 8 Steps to Quick Changeovers
What is SMED?
The 7 Steps to SMED
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The Race is Won in the Pits
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What is a Changeover?
The amount of time taken to change a
piece of equipment from producing
the last good piece of a production
lot to the first good piece of the next
production lot
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When is the
Changeover Complete?
1. Running product A
2. Downtime = Muda or Waste
3. Running product B
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Why Quick Changeovers?
1. Quick changeovers reduce lead time
2. Increase overall velocity
3. Machines only create value when
they are running and not sitting idle
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Why Quick Changeovers?
1. Reduce lot sizes
2. When lot sizes are reduced, the
customer’s lead time is also reduced
3. This is because most of the lead
time is waiting (queue time)
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Quick Changeovers Reduce
Inventory
Fast changeovers greatly reduce the
need for inventory buffers
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Improves On-Time Delivery
Performance
Removing the non-value added time
results in the customer getting their
product sooner
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8 Techniques to Quick Changeover
1. Separate internal from external setup
operations
2. Convert internal to external setup
3. Standardize function, not shape
4. Use functional clamps or eliminate
fasteners altogether
5. Use intermediate jigs
6. Adopt parallel operations
7. Eliminate adjustments
8. Mechanization
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What is SMED?
1. Single Minute Exchange of Dies
2. Developed by Shigeo Shingo
3. A system designed to radically reduce the
amount of time to perform a changeover
or setup
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Shingo’s Success
1. “A Revolution in Manufacturing: The
SMED System”
2. Toyota, using his techniques,
reduced setup time from days to
three minutes
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Focus on the Process, not
the Technology
1. SMED should be inexpensive
2. Well planned
3. Well practiced
4. Well executed
5. Without Standard Work, there is no
continuous improvement
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Shingo’s Success
Changing dies on stamping machines
took up to three days to complete
1. Placed precision measuring devices
on the die – used instead of
eyeballing
2. Tools designated for SMED were
located close by
3. Cut the changeover time to less
than 10 minutes!
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7 Steps to Implementing SMED
1. Observe the current methodology
– Watch a full changeover at least once – more is
better
– Videotape is best
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7 Steps to Implementing SMED
2. Separate the INTERNAL and EXTERNAL
activities. Internal activities are those that
can only be performed when the process
is stopped, while External activities can be
done while the last batch is being
produced, or once the next batch has
started. For example, go and get the
required tools for the job BEFORE the
machine stops.
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7 Steps to Implementing SMED
3. Convert (where possible) Internal
activities into External ones (preheating of tools is a good example of
this).
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7 Steps to Implementing SMED
4. Streamline the remaining Internal
activities, by simplifying them.
Focus on fixings - Shigeo Shingo
rightly observed that it's only the last
turn of a bolt that tightens it; the
rest is just movement.
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1. Only the final turn on a bolt
adds value
2. The interrupted screw (or
interrupted thread) provides
one means of clamping and unclamping something
quickly. Artillery breeches have been sealed in this
manner since the nineteenth century.
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7 Steps to Implementing SMED
5. Streamline the External activities,
so that they are of a similar scale to
the Internal ones.
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7 Steps to Implementing SMED
6. Document the new procedure and
the actions that are yet to be
completed.
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7 Steps to Implementing SMED
7. Do it all again: For each iteration of
the above process, a 45%
improvement in set-up times should
be expected, so it may take several
iterations to cross the ten-minute
line.
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Improvements with
Successive Runs
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Look For…
Look for opportunities to eliminate
waste in your changeovers, then go
after them.
In the following video, identify any
wasteful activities.
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Look For
1. Shortages, mistakes, inadequate
placement of needed equipment. Can be
avoided by using check tables, especially
visual ones, and setup on an
intermediary jig.
2. Inadequate or incomplete repairs to
equipment.
3. Optimization for least work as opposed
to least delay.
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Look For
4. Unheated molds which require several
wasted 'tests' before they will be at the
temperature to work.
5. Equipment using slow, precise
adjustments for the large coarse part of
adjustment.
6. Lack of visual lines or benchmarks for
part placement on the equipment.
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Look For
7. Forcing a changeover between different
raw materials when a continuous feed,
or near equivalent, is possible.
8. Lack of functional standardization, that is
standardization of only the parts
necessary for setup, e.g. all bolts use
same size spanner, die grip points are in
the same place on all dies.
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Look For
9. Much operator movement around the
equipment during setup.
10.More attachment points than actually
required for the forces to be constrained.
11.Attachment points that take more than
one turn to fasten.
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Look For
12.Any adjustments after initial setup.
13.Any use of experts during setup.
14.Any adjustments of assisting tools such
as guides or switches.
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Parallel Operations Using
Multiple Operators
Level load the changeover
Balance the tasks
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Teamwork - Parallel Operations
Using Multiple Operators
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SMED Tool Carts
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