SMED is a series of techniques to reduce as much as 94% the time it takes to complete changeovers both in the front office as well as the shop floor.
You may have come up with the problem of having to produce one product and then taking a long time to get ready to start over with the next product.
Even at home when cooking meat and vegetables you have the same problem, you can’t mix knives or plates. I also hate when I try to pay at the cashier and exactly at that moment they run out of paper for giving me the receipt, and take several minutes to change it. So why keep losing time with long changeovers when you can implement SMED?
SMED Changeover is a concept pioneered by Shigeo Shingo working at Toyota, and experience shows that it can be dramatically reduced as much as 94%.
It is one of the many lean production methods for reducing
waste in a manufacturing process. It provides a rapid and efficient way of converting, for example in a manufacturing process, from running the current product to running the next product. This rapid changeover is key to reducing production lot sizes and thereby improving flow.
SMED stands for Single Minute Exchange of Dies, which does not mean that all changeovers and startups should take only one minute, but that they should take less than 10 minutes.
Shingeo Shingo realized that Toyota (as well as all the car manufacturers in the 60’s) had a serious bottleneck in the car body molding processes. The longtime lost drove the total cost of the car, so they tried to have big lots of cars to reduce the time lost, but on the other side, they had high storage costs. Toyota found that the most difficult tools to change were the dies. The most famous change was a process that took 2 weeks in 1969 to almost three minutes to complete 6 months later.
Some of Toyota’s improvements were to place devices to help employees be more precise with heavy instruments, scheduling the die changes in a standard sequence, dedicating tools to the die-change process so that all needed tools were nearby, and scheduling use of the overhead cranes so that the new die would be waiting as the old die was removed. This way, Toyota cut the change-over time to less than 10 minutes per die, and thereby reduced the economic lot size below one vehicle.
Why would you need quick change overs?
1) Maximize production
2) Faster turnaround to win the race in NASCAR / F1
3) Minimize your customers interruption in service phone, or cable.
Parkinson’s Law states that work will expand to fill the time given for it to be executed, so if add a sense of urgency to get the work done. You generate an expectation getting it done in a shorter period of time – avoiding the downside of Parkinson’s law. Your total project maintains schedule even if some elements expand, that’s the essence of SMED.
Contrary to what you may think SMED is not just for the folks on the shop floor. “We don’t use dies here so SMED is not needed.” SMED is a concept and is just as relevant in the front Office as the shop floor. No, dies are not required, and one minute is not required either.
The aim is to reduce the time it takes to switch from the last “good” part of product A to the next “good” part of product B in less than 10 minutes.
How to implement SMED?
There are four main concepts that should be considered to SMED your process.
1) Separate internal and external activities: What steps require downtime and which ones do not? Think of what you need do when your printer needs the ink changed. Try to move as many internal steps (which needs to be done during the downtime) to being external) to be done before or after the downtime) to minimize downtime. ensure that external setup actions are performed while the machine is still running,
2) Cut out the Wastes: eliminate or reduce the 8 wastes and non-value added operations. Reduce the amount of changes required by trial and error. Create indicators or shims to identify what position is correct. Remember that defects and re-recycle is one of the 8 wastes. You can also use portable tools or replacement pieces so as to reduce transportation and waiting time.
3) Parallel changeovers: Many hands make light work, as long as the shutdown time is not costing you more than the production time. Look at the speed of a pit crew changing four tires in F1. Standardization in parts, schedules and standard procedures will help to ensure everybody knows what to do, when and how. By Observing the process you can find out shutdown constraints, or sequences of steps that don’t make sense and can be done at the same time, that is in parallel.
4) Adding power to your change-over: Do this last so you are not making external activities faster in the shutdown. For example a Vacuum is faster than a broom.
Good luck! if you have any questions, please contact us! We can help you implement SMED in your business.
Luciana Paulise
CEO Biztorming Training & Consulting
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