Gorur N Sridhar
Why do we need SMED?
Within production strategies such as lean manufacturing and just in time ( JIT), we are aiming to reduce the waste within the system, waste being one of three main areas as defined in Lean/Toyota Production System (TPS): the Waste of Muda (non-value adding), Mura (unevenness) and Muri (overburden). Waste reduction is an effective way to increase profitability.
SMED tackles all of these waste areas but its greatest strength is in helping us to achieve the elimination of Mura, which can be translated as unevenness, irregularity, lack of uniformity or inequality.
The biggest obstacle to having smaller batches is the changeover time of the equipment.
SMED is probably one of the most important lean manufacturing tools, if not the most important, for enabling just in time production.
To better understand the concept of SMED let us understand its two main components:
1. Internal activities are those activities that can only be performed safely when the equipment is stopped, an example of this can be unbolting the tool in the machine etc. 2. External activities are those that can be performed when the equipment is in operation, such as fetching the next tool etc.