Continuous improvement tool that methodologically seeks to reduce the time reference exchange machines production environments.

SMED is the acronym in English of Single Minute Exchange of Die, which in Spanish means “die change in less than 10 minutes.”

The SMED was born of the need to reduce the size of the lots that passed by stamping presses, by optimizing the switching time employee moving from one array to another.

Today the SMED preparations applies to all kinds of machines.


To discuss the SMED should be clear about a number of concepts:

Changeover time is the time since the last piece of the outgoing product is manufactured to the first part of the incoming product OK. Therefore, during the changeover time the machine is stopped.

Preparation: operations necessary for the reference change. All preparation is waste (MUDA), as it does not add value for the customer.
internal preparation: preparation operations can only be carried out with machine stopped.
external preparation: preparation operations that can be performed with the machine running.
What is the SMED?

SMED serves to reduce the changeover time and to increase the reliability of the change process, which reduces the risk of defects and breakdowns.

Reducing the time reference exchange can be used in two ways:

To increase OEE and Productivity. Keeping both the frequency change references as the size of the lots.
To reduce the stock in process. Increasing the rate of change of references and reducing the size of the lots.
From the point of view of Lean Manufacturing always interested in reducing stock levels.

Increased Productivity OEE and be bound to go just that our ability to meet customer demand.


How the SMED works?
In 1969 the father of SMED, the Dr.Shigeo Shingo, defined its fundamentals to get reduce changeover time of a press of 1000 tons of 4 hours to 3 minutes, there emerged what “less than 10 minutes.”

Although the definition of SMED is talk of reducing setup times in less than 10 minutes, this is not always possible.

The completion of the SMED follow 7 steps:

Previous preparation
Analyze the activity on which will focus the SMED workshop.
Separate the internal from the external.
Organize external activities.
Making the internal in the external.
Reduce the times of internal activities.

Let’s look in more detail:

1) Advance Preparation:

This stage consists of two parts:


Know the product, operation, machine, plant layout (layout), the existing preparation instructions …
Get historical data preparation times (this data will only be useful if the situation in which they were taken is comparable to starting).
Observe the insitu preparation.

It is form a team, give the necessary training on the fundamentals of SMED and in turn give the necessary means to do so.

About the team must consist of:

Person / s with experience in the preparation.
Person / s with capacity to make technical changes
Person / s with ability to make organizational changes.
About the media:

Camcorder battery and enough memory cards.
Map of the distribution plant with a size that allows be handled.
Paper and pencil.
A meeting place team to analyze all data and allows to visualize the recordings.
2) Analyze the activity on which it will focus the SMED workshop:

It is filming in detail each and every one of the activities performed during the reference change. In the event that several people involved in it all should be recorded.

The recording start after the end will manufacturing the last piece of reference projection and the end of recording will start with production of the first part of the incoming reference OK.

If the machine does not extract a piece OK is considered to continue within the preparation and in these cases, checking the quality of the first manufactured part it can be considered as the last step of preparation.

After making the recordings and already in a room, shop equipment SMED use the recordings to detail all the activities that comprise the process of change from baseline, indicating to turn its duration. Thus obtained time standard process cycle.


3) Separate the inner from the outer

In this phase all team members are reviewing each and every one of the above activities to identify those that may be external.

At this point we should remember what indicated at the beginning of this post. An outside activity is one that can be done with the machine running and therefore its runtime does not affect the total cycle time of the process.

Hence the importance of making more activities can the process of change in external reference.


4) Organize external activities

As outside activities you can do with the machine, at this stage the team should make a planning exercise in order that all external activities are prepared at the time will begin the process of changing reference.

The result of this stage is usually a check-list to do in the area where he is making the SMED workshop.

Some of the considerations that usually collect this list:

What preparations need to be made in advance ?; What tools and parts need to be hand operators who make change ?; where should they put the tools and parts ?; Are the tools and parts in good condition ?; where should put the item (useful, matrix, etc.) after removed;? How are transported tools and parts ?, etc.

5) To convert internally in external

For each of the activities that have decided to become external equipment should define the Action Plan to follow to achieve this conversion.

Thus for each activity should be stated to be done, who will do what and when to have it done.


6) Reduce the times of internal activities

In this phase the team should raise ideas for improvement to reduce the execution times of internal activities.

Once defined an idea for improvement and this has been accepted by all, the team must define the Action Plan to follow to implement this idea of improvement.

Again: to be done, who will do what and when to have it done.

7) Track

Once finished the SMED workshop for the first time is vital to track to see if the new defined standard deviations suffers and if so, to take corrective actions.

Thus monitoring is usually done is based on 2 supports:

Record all incidents that have occurred during the week. On the Check-list you can be done.
Record all times of change that occur during the week and then, in a graph, represent the maximum, minimum and average each week. The evolution of the data reveals deviations.



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