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The SMED method: reducing time and costs

In production environments, SMED (Single-Minute Exchange of Die) introduces the idea that any initialization of a process should not take more than ten minutes.

This is why SMEDs were born from the need to reduce the size of the batches that passed through the stamping plates. The application of the SMED method allowed not only to reduce time, but also to optimize the entire production process. For what is currently used for the preparations of all types of machines in different areas.

What is SMED for?

By reducing the times we use to change the production process of a certain product, SMEDs can generate significant competitive advantages by reducing the size of inventories, maximizing production capacity and flexibility, and of course, minimizing production times.

With this, we can produce several models on the same production line. Which allows reducing costs and achieving more agile and flexible demand changes.

The SMED process is divided into four stages:

1- Study of the change operation: in this stage we seek to evaluate the processes or machinery to know their functionalities and thus, project or develop changes.

2- Separate internal and external tasks: at this point the different types of tasks are determined, understanding as internal the operations that must be carried out with the machine stopped, while the external ones are those that can be carried out while the machine is running. This stage of differentiation is fundamental for all processes related to SMED.

3- Convert internal tasks into external ones: this is the most difficult point of the entire process, since it requires a deep analysis by the development team, where it is sought to determine what tasks can be performed before stopping the machine, or in parallel, and if that way they will directly reduce the detention time.

4- Refine the task process: some changes used in this process can allow us to reduce the time required to make a model change, improve the ability to make more model changes, manufacturing smaller batches and planning a delivery time accordingly and minor storage. Generally, with the application of this methodology it is possible to reduce stock and thus considerably improve waiting times.

What is the SMED for?

The SMED serves to reduce the changeover time and to increase the reliability of the changeover process, and thanks to this, it is possible to reduce the risk of defects, faults and breakdowns.

With this, the reduction of the reference change time can be exploited in two ways:

– To increase Total Equipment Effectiveness (also known as OEE) and Productivity. With what it is also possible to maintain the frequency of change of the references such as the size of the batches.

– To reduce the stock in process: this is achieved by increasing the frequency of change of references and reducing the size of the batches.

How does the SMED work?

In 1969 Shigeo Shingo, considered the father of SMED, defined its fundamentals by reducing the changeover time of a 1000-ton press from four hours to just three minutes, hence the concept of “less than 10 minutes”.

Although the definition of SMED speaks of reducing preparation times in less than 10 minutes, we must be aware that achieving this will not always be possible, since for all this method to work correctly, it is necessary to coordinate different processes that can work harmoniously.

How does the SMED work?

In 1969 Shigeo Shingo, considered the father of SMED, defined its fundamentals by reducing the changeover time of a 1000-ton press from four hours to just three minutes, hence the concept of “less than 10 minutes”.

Although the definition of SMED speaks of reducing preparation times in less than 10 minutes, we must be aware that achieving this will not always be possible, since for all this method to work correctly, it is necessary to coordinate different processes that can work harmoniously.

This is why the SMED consists of seven steps:

1. Previous Preparation

This stage consists of two parts:

– Investigate: during this stage we seek to obtain historical data on the preparation times. For this, it is necessary to observe the preparation in situ, know the product, the operation, the machines, the plant distribution (layout), and the instructions for the preparation that is carried out at that time.

2. Create a team

At this point it is necessary to build a working group, a necessary training on the fundamentals of SMED and give it the necessary means to carry it out.

This team must be made up of workers with experience in preparation, people with the capacity to make technical modifications and also members of the organization who can make organizational modifications.

3. Analyze the activity on which the SMED workshop is going to focus

During this stage it is necessary to document (hopefully with audiovisual recordings) in detail all the activities that are carried out during the change process. If several people participate in the activity, all of them must be recorded.

Following this documentation, the SMED workshop team will use the recordings to detail all the activities that comprise the referral change process. Thus, the standard cycle time of the process can be obtained.

4. Separate the internal from the external

At this stage it is necessary for all team members to review all activities of the production process in order to identify which are internal and external.

At this point it is necessary to detail to all team members that the external activities are those that can be carried out with the machine running and therefore their execution time does not affect the total cycle time of the process.

5. Organize external activities

As external activities can be carried out with the machine running, at this stage it is necessary for the team to carry out a planning exercise so that all external activities are prepared at the time of starting the reference change process.

With the results obtained by the team, a check-list can be developed to make the process easier in the future.

Among the considerations that this list usually collects, it stands out.

What are the preparations that need to be done in advance? What tools and parts need to be at hand for the operators who are going to make the changes? Where should the tools and parts be located? Are the tools and parts in good condition? Where should the elements be placed after disassembling? How will the tools and parts be transported? Among other questions that must be defined.

6. Convert internal to external

This process is essential, since it is where the team must define an action plan to achieve the conversion of all the activities that the team has decided to convert into external. In addition, for each activity it must be determined what is going to be done, who is going to do it and their deadlines to have it finished.

Reduce the times of internal activities:

At this stage, the team must come up with ideas to improve the execution times of internal activities, seeking of course to reduce them.

Once an improvement idea has been defined, the team must define an action plan to implement that improvement idea.

7. Follow up

After the SMED workshop, it is necessary to follow up to see if the new defined standard is being met or there are deviations, and in that case, how they can be fixed or corrective actions taken.

Monitoring is usually supported by two supports:

– Register all the incidents that have occurred during the week.

– Record all the times of change that occur during the week and then, in a graph, represent the maximum, minimum and average values ​​of each week. The evolution of these data shows all possible deviations.


According to everything we have reviewed, the SMED method implies an excellent opportunity to reduce time and costs in our production processes. A system that, although it requires a very complete coordination of different units and work teams, its results constitute great advances in the optimization of internal processes and the relationship with our customers.

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