SMED method

In the SMED method, the optimal time unit is considered to be 10 minutes, during which there should be a complete changeover of the machine. In practice, in many cases, this is not possible. However, it is possible to significantly reduce the duration of the changeover process. How, and what final result can be achieved depends on many factors. The idea is to reduce this time and optimize processes before changeover. The SMED method is an important element of the Lean Manufacturing system.

The four steps of the SMED method

The SMED method assumes using as few tools as possible. It is also important to do machine-independent work before changeovers. Thanks to this, the time of introducing changes in the machine is shorter, and thus the production process is more effective. The introduction of the SMED method is preceded by four stages.

Stage 0

Consists in detailed observation of the standard course of changeover. It is filming the whole process (with the use of a camera or a phone), and then analysing particular activities which are performed during changeover. The effect of the analysis is a list of actions performed in the process along with their duration.

Stage 1

This stage divides the actions into internal and external changeovers. Internal are all actions, which can be done only after switching off the machine. External changeovers, on the other hand, are activities which are performed outside the machine. Internal changeovers cause time losses and downtime, so it’s worth to shorten them or eliminate. A lot of attention is also paid to ensuring that there are necessary tools and qualified people on site and that communication between departments is improved. At this stage, it is worth looking at the organization of the workplace where changeover is performed.

Stage 2

Involves the transformation of changeovers themselves. Internal operations are transformed into external operations. Statistically, it is machine adjustment and testing that take the most time in changeovers. Therefore, it is important to set a standard that will speed up set-up or transform it into an external process.

Stage 3

This stage consists in rationalization of particular elements of changeover. It concerns introducing organizational, logistic and equipment solutions, which will significantly accelerate changeover, without any negative effects such as decrease in efficiency or deterioration of quality.

In practice, this stage of the SMED method consists of placing the necessary tools right next to the machine, the organization of the arrangement of these tools, or the replacement of fixing or regulating elements to those that can be fixed in one motion, so that this is done as quickly as possible. In this way, traditional screws can be replaced by quick connectors, clamps or pins, traditional wrenches – by screwdrivers. It is recommended to draw up a list of tools and materials necessary for the changeover and to develop a procedure and instructions for the process. Moreover, the analysis of conducted works may show that it is worth to delegate additional worker to changeover.

What are the benefits of using the SMED method?

SMED reduces machine changeover times in real terms. As a result, capacity rates increase, not least because the entire process is simplified and shortened as much as possible, thereby reducing lead times. Production is more flexible, so the company can better respond to customer needs. Shorter downtime results in less waste, increases the flexibility of the production system and thus improves the liquidity of the plant. SMED also indirectly improves work safety in the plant.

Learn more about the benefits of implementing the SMED method in this article.