What SMED (Single Minute Exchange of Die) Is and How to Implement It In Your Factory

SMED (Single minute exchange of die), is a Lean Manufacturing technique that allows significant reduction of product changeover times of machines in production environments.

What Is SMED? | Benefits of SMED | How SMED Works? | How to Implement SMED? | SMED & M-Box

What Is SMED?

SMED (Single minute exchange of die), is a Lean Manufacturing technique that allows significant reduction of product changeover times of machines in production environments. SMED method means to convert as many changeover steps as possible to “external” (performed while the machine is running), and to simplify and speed up the “internal” steps (could be performed only when machine is stopped).

Shingo Shigeo

SMED was developed by Shigeo Shingo during the period of 1950-1969, when Toyota presented great losses in its lines of stamping due to the high changeover times of die between different references. This motivated Shigeo Shingo to introduce the idea that any change of product should last less than 10 minutes, with the phrase “Single minute exchange of die” emerging from there.

The Benefits of SMED

Increase of OEE

SMED helps to increase the OEE (overall equipment effectiveness), since a reduction of the changeover times implies a reduction of the machine downtime which immediately generates an increase in its availability.

Decrease of Defects

 The reduction of the changeover times favors the flexibility and can allow lower batch sizes, which in turn decreases defects generated by the excess of production of a same reference.

Smaller Production Runs

Smaller production runs allow lower stocks for raw material and finished products, which is in line with the general idea of Lean Manufacturing. This will also free up finance resources, increase available warehouse space and minimize costs of quality defects that may occur within a production run.

Flexibility & Productivity

The added flexibility and increased productivity to SMED, are competitive advantages that, when translated in the improvement of the companies’ capability to respond to market, demand changes.

How SMED works?

To understand how SMED works, it is necessary to review a series of basic concepts:

Changeover time: the time that elapses since the last piece of product A (outgoing product) comes out until the first piece “ok” of product B (incoming product) comes out.

Changeover operations: all activities necessary to carry out the format change.

Internal operations: all activities of change that can only be done with the machine stopped.

External operations: all activities that can be carried out while the machine is running.


6 main steps to make SMED work

Step 1: Measurement of the current Changeover Time

This activity is essential to know where we are and to see where we are going. The simple and precise measurement, as well as the recording of changeover times, will allow the analysis and support of each one of the decisions to improve them.

Step 2: Identification of internal and external operations

This implies defining which activities of change are currently running as external and which of these as internal, this also implies knowing the individual time of each of these activities.

Step 3: Convert the largest number of internal operations to external

Reassess each of these activities to define which activities can be executed as external

Step 4: Minimize the times of internal operations

Optimize the execution time of all internal activities through action plans agreed on as a team.

Step 5: Standardization of the new procedure

The development of a pattern of monitoring the new way of doing the activities, encompassing the definition, communication and adherence measures to the new standard.

Step 6: Follow-up

The registration, analysis of indicators and the continuous improvement of changeover times.

What is needed to implement SMED?

It is essential for the implementation of SMED to have reliable and immediate data on the interruption times of the machine due to product changeovers, as well as product quality controls. These data allow us to establish the exact current changeover times, establish objectives, make well-supported decisions about them and achieve their continuous improvement.

Implement SMED in your factory with the help of M-Box

The M-Box production monitoring system collects the relevant and unbiased data in real time for analysis to ensure the optimal implementation of SMED, and thus advance the path of improving productivity and flexibility of Lean Manufacturing.

SMED & M-Box System