Single Minute Exchange of Dies (SMED in short) is the process of changing and exchanging of dies and other tools in 9 or less minutes. Shigeo Shingo developed it for Mazda. The term gained a popularity from his book – Revolution n manufacturing Single Minute Exchange of Dies SMED system.
Changeover: It is the process of changing of line or machine from one product to the other and starts from at the end of last good product of the previous batch and ends with first good product of the new batch.
Single Minute Exchange of Dies (SMED) helps in quick change over
Quick change-over has many advantages for a manufacturing system,
- Reduced lead time
- Improvement of the quality and flexibility
- Reduction in batch size
- Increased capacity of the machine or line
- Reduced work in process
Internal set up activities:
Those activities that can only be done when the machine is stopped.
Some of the activities that could be practiced as internal set up are:
Positioning, adjusting, aligning or removing tools.
External set up activities:
Those activities that can be performed even when the machine is running
Some of the activities that could be practiced as external set up are:
The Single Minute Exchange of Dies SMED could be performed in the following 5 stages
- Observation and data record
The data should be recorded from the site and a VSM and process map of the ongoing process should be drawn. The activities that are ongoing may well be recorded in a video so that any missed activity could easily be seen and revised at any point of time by looking the recorded video.
- Separation of the internal and external activities
It is always important to perform the brainstorm what activities are taking time in the machine setup and changeover and whether they are the internal activities. Prepare a list of activities in the changeover that are internal and external.
- Conversion of internal activities to external
As far as possible internal activities should always be changed into external activities. This is important both the ground of cost and time issue. It is also not advisable to make too many external activities. Work should be simpler and those external activities should also be reduced and automated as far as possible.
- Streamline the activities
The knots and bolts in the machine should be removed or replaced as far as possible. Also, the number, heights, weights, location of the change parts and their function should be standardized so that they become easy to use without confusion in the future.
- Documentation and standardization
In this stage all the new internal and external procedures are recorded and documented. SOPS (Standard Operating Procedures) are developed and work is standardized.