SMED explained while doing laundry – part two

In part one I explained SMED is a systematic approach to quick changeovers in order to minimize machine downtime.

In order to explain what SMED is good for to non-specialists, I used the laundry example, in which the mundane washing machine is a very precious resource and it should wash (add value) as much as possible in 24 hours a day. Conversely, such a precious resource should be protected from any downtime, especially when changing (laundry) batch.

After describing a typical lengthy and far from efficient changeover, this second episode will show how to drastically improve the performance by reducing the changeover duration.

Distinguish internal and external setup

The very first thing to understand when striving to reduce changeover duration is to distinguish internal and external setup operations.

Internal Setup (IS) operations are done within the machine or so close to it that safety requires to have it stopped to achieve them. Typically changing a tool fixed on a machine or adjustment inside the machine.

External Setup (ES) operations either have nothing to do with the machine itself, like filling a tracking record form or bringing raw material from warehouse near to the machine, either can be achieved without endangering oneself. ES operation can be achieved while the machine keeps running.

Many times, some operations and task are first seen as External Setups, but after closer analysis are totally unnecessary. This happens often when countermeasures to some old problem have not been suppressed after the problem was settled.

Internal and external setup with laundry

Back to our laundry problem; what are internal and external setups?

Considering the chart of a typical changeover as displayed hereunder,


The time wasted until “operator” noticed the end of washing cycle is no Internal Setup nor is it External, it’s just plain waste and must not happen.

“Searching for empty clean basket” to receive the washed laundry and “searching for detergent” and “sorting laundry” should not happen at the expense of machine time. These operations should be included in preparation prior to changeover, which is External Setup.

If work environment, here laundry room, is well organized and tidy, searching for items like basket and detergent should be unnecessary. Even so in preparation – External Setup – this time is not impeding the washing machine performance, it can be saved for more valuable occupation.

The changeover duration after separating ES and IS should be drastically reduced to almost bare minimum. Almost, because the remaining IS operation are likely to be optimized (reduced).

The changeover process after improvement should look like this:

This simplified laundry example is very similar to the changeover duration optimization done in production lines, machining cells, etc.

Important notice

When working to reduce the machine downtime during changeovers, most of people try to improve some technical aspect like fittings, fastenings, jigs and so on. As this fictional example shows, most of the improvement potential is found in organization.


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2 thoughts on “SMED explained while doing laundry – part two

  1. This is still my favourite TPS technique. It was the one that opened my eyes to the power of TPS in the late 1980’s. I subsequently had the opportunity to study setup time reduction (SMED – single minute exchange of die – 9 minutes or less) under Shingo’s guidance. The genius of Sensei Shingo was the simplicity of his thinking. —
    The SMED system starts on the basis that there are two categories of setup activities. —
    Internal activities. (Ti) These are the activities that are conducted inside the machine/process & require it to be stopped to conduct them safely. —
    External activities. (Te) These are the activities that do not require the machine to be stopped to complete them & could be completed before or after the changeover. —
    Preliminary stage. —
    The first action is to study the changeover & record the steps taken, the total time (Ti1) & the time for each step. The timing must start as the last piece of the previous batch is completed & finishes when the first piece of the next batch is completed running at the required speed & quality. (When timing the work, record the steps with regard to being internal or external). —
    We have found the ideal study team is; I setter. I observer, their job is to record and time the detailed steps of the setters activities. 3 fact collectors, these individuals record on post-it notes the detailed facts of the setter’s activities in each step.
    Step 1. Separate internal & external.–
    Using the study chart, Separate the step times into internal & external categories. Take the total of the external times (Te1) from the original total time (Ti1) & this is the new changeover time (Ti2). These external activities will now be conducted before or after the changeover. They will be individually improved in a later step. —
    Step 2. Convert internal to external. —
    Study each internal step & ask if it could be conducted as an external activity, done before or after the changeover while the machine is running. Taking the total time of these externalised steps from (Ti2) will give the new internal time (Ti3). Add this externalised time to the previous external time (Te1) and you have the new external time (Te2). —
    Step 3. Streamline all activities. —
    Study the details collected on the post-it notes about each of the internal (Ti) & external (Te) activity steps & improve them. Take the time saved from (Ti3) and (Te2) to arrive at your final internal & external times (Ti4) and (Te3). —
    Write an action sheet to implement the changes required, & SOP’s for all the new internal & external procedures. Go back & repeat. —
    Some key points. —
    The core of a SMED team must be the setters & their support people i.e. tool room, maintenance, operators etc. They can do all the work required. We have conducted over 200 two day SMED events & this is the delegate mix we use. On day one we show the delegates the Shingo methodology and let them practice on a practical pantograph machine. On the second day they move to the shop floor to demonstrate what they have learnt. They will normally demonstrate a 50 to 80% reduction.–
    When the setup starts no one should have to leave the machine. — Remember the basic rules of improvement is; Can we remove it before we improve it? Can we simplify it? Can we combine it? — Ask 5Y’s for each action in every step. — Eliminate all form of adjustment; everything should have a pre-set position & conditions. Standardise all shapes & sizes.–
    Use parallel working where possible. (You must have safety interlocks for each setter). —
    Define the work you are trying to perform, & eliminate all motion that does not contribute directly to its achievement. –(Work is defined as the motion required to produce what the customer requires). —
    One of the best examples of Shingo’s system is a F1 car pit stop. Your machine/process is in a race with your competitors. When it roars into the pits is everything ready, is it back in the race as quickly possible & giving the performance required? —
    Remember our goal is to achieve the 2 D’s; Delays – Minimum. Damage/Danger to our people – Zero. —
    I have found that the combination of the work v motion equation & 5 Y’s thinking, along with the ‘remove it before we improve it rule’, can achieve amazing results in the hands of our front line people.

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