SMED Part 3 – Reducing Trials

A commonly used lean tool/concept in manufacturing is Single Minute Exchange of Dies (SMED) or quick changeover.  By definition changeovers from one job to the next is waste.  It does not add any value to the product/service, nor is the customer willing to pay for it.  Since it is waste but necessary in many operations, the goal should be to be as quick and as efficient when changing over as possible.

Shigeo Shingo showed how getting changeovers done in just a few minutes can reduce the batch size that can be produced, which creates less inventory and increases the cash flow.  When achieved, a changeover that is done in less than 10 minutes will save a lot of money.  The ideal state is to get the changeover to instantaneous so no capacity is lost.

During my time I have seen what I call three levels of the SMED concept that can help depending on where you are with implementing quick changeovers or lean.  This is the third of three parts explaining the different levels I have seen.  I hope this will help others with their SMED efforts.

The last topic in this three part series is about reducing the number of trials at start up.  The definition of a changeover is from the last good piece of the current run to the first good piece of the next run.  So any trials to align or purge or anything else in order to get a good piece is considered part of the changeover.

Here are a few suggestions to get the thinking started on how to reduce the number of trials during a start up:

• Pre-set adjustments – This is where you can adjust your machine quickly to a pre-determined setting that should be very close if not exact for the job you will be running
• Offline fixturing – Create a fixture offline that simulates the functionality of the machine.  Then set up the press to receive the pre-positioned die just like the fixture does.  This should help on the accuracy of the process.
• Set pins – Build pins that would allow a fixture (such as a screen) to be set in the same place every time.  This will help with pre-set adjustments and sliding in a fixture that was aligned offline to be accurate each time.

The three things I have discussed about SMED are not the only parts of SMED.  There is a lot more to SMED and quick changeovers that can help.  Learning to become very quick with changeovers can really help drive the business in reducing inventory and increasing cash flow.

SMED Part 1 here

SMED Part 2 here