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SINGLE MINUTE EXCHANGE OF DIES
(SMED)
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.
Total elapsed changeover time, Tc =Run-down period + Set-up period + Run-up period
3
What is SMED?
Single Minute Exchange of Dies
Developed by Shigeo Shingo
A system designed to radically reduce the amount of time to perform a changeover or setup
History
The concept arose in the late 1950s and early 1960s, when Shigeo Shingo, was consulting to a variety of companies including Toyota, and was contemplating their inability to eliminate bottlenecks at car body-moulding presses.
• 1950-Forms first stage of SMED : Involves splitting a setup operation into internal and external set ups
• 1956-58—Worked for Mitsubishi Ship buildings• Invents a new system for hull assembly of 65,000 ton super-
tanker• Cut time from four months down to three and than two
months• 1970-Originated SMED system at Toyota • Wrote more than 14 books
• Including Toyota Production System
Pit stop in F1 Race
https://www.youtube.com/watch?v=RRy_73ivcms
The reduction of time in pit stops during F1 races is one of the beautiful example of SMED.
Reducing Set-Up Time
Stages Of SMED
TOTA
L SE
T U
P T
IME
INT
ER
NA
L SE
T U
P T
IME
120 MINS
STAGE I
Segregate Internal External Elements
STAGE II
Convert some Internal Elements or parts of those to External Elements
STAGE III
Reduce times of residual Internal Elements
80 MINS
40 MINS
7 MINS
The SMED Process
Observe the current methodology.Separate internal and external Operations.Identify the tasks which can be eliminated.Convert maximum internal operations to external
Operations.Streamline the remaining Internal activities.Streamline External activities.Document the new procedure and the actions that
are yet to be completed. Do it all again.
1. Observe the current methodology
Watch a full changeover at least once – more is better.
Do documentation of all the activities happening during the changeover.
Data recording Format
Company NameProcess : Roll Change Area : Machine No : Start Time : Name :
S.No. ACTIVITY TIME(min) INTER
NALEXTERNAL
NEEDED WORKS
MOTION
TRANSPORTATION
WAITING
SEARCHING
ELIMINATE
COMBINE
REDUCE
SIMPLIFY
REMARK
Look for
Shortages, mistakes, inadequate placement of needed equipment.
Equipment with slow adjustments for the large coarse part of adjustment.
Proper placing of all required equipment which are used.
Lack of functional standardization, that is standardization of only the parts necessary for setup, e.g. all bolts use same size spanner, Same type of bolts used, die grip points are in the same place on all dies.
Look for
Much operator movement around the equipment during setup.
More attachment / bolting points than actually required.
Attachment points that take more than one turn to fasten.
Any adjustments after initial setup.Any use of experts during setup.If there is waiting for anything.
2. Separate internal and external Operations.
Separate the INTERNAL and EXTERNAL activities.
External Operation : One that may be completed while machine is in operation.
Internal Operation : One that requires the shut down of the machine for completion.
3. Identify the tasks which can be eliminated.
Look for operation / tasks which can be eliminated like, waiting for tools, waiting for crane, etc..
4. Convert maximum internal operations to external Operations
Convert (where possible) Internal activities into External ones.
5. Streamline the remaining Internal activities
Simplify the remaining internal activities
For e.g. It's the last turn of a bolt that tightens it; the rest is just movement.
And also adopt parallel operations.
The interrupted screw (or interrupted thread) provides one means of clamping and unclamping something quickly.
6. Streamline External activities.
Complete all the external Activities before the change over happens.
7. Document the new procedure and the actions that are yet to be completed.
Document all the activities which occurred.
Note all the activity which are not completed and make action plan.
8. Do it all again
Repeat all the steps for the next change over.
Example Tools
Split thread bolts
Example Tools
Example Tools
Reduce the amount of turns required in order to activate the screw.
Shadow Board
Benefits of SMED
• Increases throughput by reducing setup times
• Eliminates setup errors• Increases safety• Reduces the cost of setups• Reduces waiting times and inventory
buildups• Reduced setup time