Quick Changeover & SMED Overview

What is a Changeover?

Formally defined in manufacturing terms, a changeover is simply the amount of time taken to change a piece of equipment from producing the last good piece of a production lot to the first good piece of the next production lot. Now if you work in a hospital or office area or any other non manufacturing environmesimply replace the words last good piece with

last good unit of one type of work.

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One of the best ways to learn about quick changeover is to watch a pit crew operate at a Formula One or NASCAR race. It goes without saying that the ability to get the car back onto the track as quickly as possible can mean the difference between winning and losing… and so it is with producers of any product or service. We too need to be able to get our equipment, or value added processes, up and running as quickly as possible.

What is SMED? SMED, which stands for single minute exchange of dies, is a system focused on dramatically reducing the time it takes to perform changeovers or setups as they’re often called. SMED was actually developed ~ 50 years ago by a man named Shigeo Shingo who was working for the Toyota Motor Company as a consultant. In those days Toyota needed to reduce inventory of automobile stampings and began looking for ways to perform changeovers in a more efficient manner. As it turns out Shingo was able to collaborate with Toyota engineers on a method that reduced a 4 hour changeover on a 1000 ton press to less than 3 minutes. Yes, that’ right… 4 hours to 3 minutes! This example as well as an excellent description of the overall SMED process was documented in the book “A revolution in manufacturing: The SMED System.” So it goes without saying… if you don’t already own this book I highly encourage you to pick a copy up.

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Why Quick Changeovers? There are many reasons companies should focus on reducing the time it takes to changeover their equipment and processes.

1. The first reason for quick changeover is that is leads to the reduction of lead time. You see, quick changeover leads to increased velocity. In other words you’re able to create value faster when your machines are running and not sitting idle.

2. Another reason quick changeover reduces lead time is related to lot sizes. You see, when lot sizes are reduced the lead-time, or the time from when a customer orders a product until it’s received, is also reduced.

3. Next, as a result of this improved flexibility and reduced lead time quick changeover also improves on time delivery performance.

4. Quick Changeover also enables a dramatic reduction of inventory which reduces inventory carrying costs and increases cash flow

5. Finally, quick changeover enables heijunka or production leveling.

8 Steps to Quick Changeover

1. The first step to quick changeover is to document reality. Many companies have found a video camera to be the best tool to make this happen.

2. The second step has us separating what we refer to as internal and external tasks. Again, we’ll discuss this in great detail in an upcoming module but the quick explanation is that internal tasks can only be done when the machine has stopped running while external tasks can be done while the machine is running. For example, you can gather your tools and complete paperwork while the machine is cycling a part.

3. The third step has us shifting internal activities to external activities. In other words, we want to do as much as we can while the machine is running so when it does stop we can quickly get it back up.

4. The fourth step has us streamlining all external tasks. In other words, even though the machine is running we still need to be as efficient as possible when completing external tasks like paperwork and preparing for the next changeover.

5. The fifth step is often not discussed when teaching SMED or quick changeover but is absolutely necessary. This step has us identifying parallel tasks. Two people, working in harmony with one another, can go much faster than one person working by themselves.

6. Next, the sixth step has us streamlining internal tasks. In other words, once the machine is down and isn’t producing parts we need to find ways of getting it back up and running as fast as possible. There are many different techniques and methods to go about this… and we’ll share many of these with you in an upcoming module.

7. The seventh step is another extremely important one that often gets glossed over by many teachers of quick changeover… and this step has us practicing the new and improved changeover method.

8. Lastly, the eighth and final step has us documenting the new standard in such a way as to ensure it’s done in a repeatable and reproducible manner.

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