The SMED, Single Minute Exchange of Die, is a tool that has proven itself in the industry. It is quite simple to implement. SMED generates gains of 30 to 70% over the time required for a tool or series change. In this article, I will remind the basics of this tool as well as the technique of implementation. I will then suggest situations in the service sector where it could be used and provide significant gains. Single minute stands for single digit minute, so less than 10 minutes, not one. 😉
Let’s give Shigeo Shingo his creation: it is at Toyota that this tool has been formalized. It tackles the time required to change a tool and aims to reduce batch sizes and increase the flexibility of the company.
The original problem is as follows: on a sheet metal press, a tool is mounted and form doors of a vehicle model. It takes several hours of work and adjustments to change the tool and produce the doors of another vehicle. Therefore the batch sizes have been increased. To maximize profitability (production time of good parts), the company makes the same part for several days. They create a large stock, then change tools and start again. The production of large intermediary stocks has two problems. First, it increases costs, such as immobilization or storage area. Second, the risk of defects on a large number of parts is higher. If the defect is detected during assembly, it is the production of several days which will have to be corrected or destroyed. With this in mind, Shigeo Shingo has formalized this quick tool exchange.
What is SMED about ?
A tool or die change is defined as the time between the production of
- The last good part of the A series and
- The first good part of the B series.
In the traditional industry, this time therefore involves the removal of the tool, the cleaning the machine, setting up the new tool and adjustments. During a SMED workshop, which is generally conducted in the form of a kaikaku, the group observes several tool changes and notes all the operations performed between these two moments. The group should include operators, maintenance personnel and methods. All the operations performed are evaluated using different filters:
- List all the operations that can be performed in a hidden time: get a tool, prepare the raw material of the next production, … These operations are called external, because they can be performed outside of the production shutdown time.
- Transform internal operations (which require the shutdown of the equipment) into external operations: programming settings, …
- Reduce the execution time of internal operations: use of templates, production standards, … During this step, operations can even be deleted!
- Finally, reduce the execution time of external operations.
The application cases in the industry are numerous: color change on a paint line, change of mold on a press, change of publication on a printer with large volume, change of drug on a pharmaceutical line, etc.
SMED at everyone’s service
The application is evident on automated equipment, it is less so on manual or intellectual processes. Here are some examples of where the SMED could apply, the best known being, of course, the change of wheels during Formula 1 races.
SMED for manual processes
In the commercial sector: setting up or withdrawing a rebate or promotion. In this case, we will try to reduce the time required to set up or remove the labels marked “-20%” and the unavailability of the computer system to make the changes. The staff who performa this operation are paid. However they do it while the store is closed. Hence the importance of reducing the time of change.
In a hospital: the change of patient in the operating room and the release of a patient room are good examples of “change of series”. A series of actions must be performed to be able to move on to the next. The shorter the downtime is short, the more patients will be treated.
SMED for intellectual processes
In a customer service company, the time of change between two customers is also a time to reduce. While the person finalizes the file, it is not present for another customer. If the processing time after seeing a client is long, it will take more staff to support more clients. Reducing the processing time between customers improves the quality of service.
Moving the folder closing tasks at the end of the day does not change the problem. Although the treatments are done in the absence of customers, there require the same amount of time. If the process was shorter, the company could offer a larger range of opening hours for customers.
In IT services, updating or migrating a database, a website are cases where the SMED can be used,. In those cases, the goal would be to reduce the downtime and downtime of systems for users.
The SMED is about reducing downtime during a change of die. Its technique is proven and can be used in different sectors