What is SMED and Quick Changeover

What is SMED and Quick Changeover Video Transcript

I’d like to welcome you to the Quick Changeover Course. Now, in this first module, we’re going to introduce Quick Changeover as well as a powerful Lean concept, known as SMED, or Single Minute Exchange of Dies. And specifically, by the end of this module, you’ll know what both Quick Changeover and SMED are as well as why Quick Changeover is so important. And we’ll wrap this module up by introducing the eight steps to Quick Changeover.

And lastly, similar to our dealing with the Seven Deadly Waste Course, we’ll be visiting with the Lean thinkers of Ram Technologies throughout this course as we witness an actual Quick Changeover event take place. But first things first.

Let’s start off by defining exactly what we mean when we refer to a Changeover. Well, 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. And if you work in a hospital or office area, or any other non-manufacturing environment, simply replace the words, “last good piece” with “last good unit of one type of work.”

Now, 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 say 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 the 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.

Now, to make sure we have a good grasp of this definition, let’s look at a simple example. First, let’s assume we’re running product A. Let’s also assume we come to the end and we’ve successfully produced a product A and the machine stops running. Well, since the operator knows that he must now get prepared to run product B, they begin the Changeover Process which might include gathering the needed parts, tools, drawings, paperwork, and work instructions. While all of this results in machine downtime, which is pure muda or waste, since no value is being created for the end customer.

Finally, after some time, the operator is able to get the machine ramped up and is busy fine-tuning and tweaking things as they produce the first good part, which we are calling product B here. Now, once the operator has successfully produced a product B, the Changeover is complete.

Okay, well, let’s envision the worst case scenario. Let’s imagine the operator has made it all the way to the end and has produced a product B, only to learn it’s defective in some way. Well, the question is, is the Changeover complete or not? Well, the answer is no, it’s not. Since, again, the definition of a Changeover is 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. All right. So that’s what Changeover is. Now let’s learn what this thing called SMED is all about.

Well, SMED, which stands for Single Minute Exchange of Dies, is a system focused on dramatically reducing the time it takes to perform Changeovers or set-ups as they are 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. Well, in those days, Toyota needed to reduce inventory of automotive stampings and began looking for ways to perform Changeovers in a more efficient manner.

Well, as it turns out, Shingo was able to collaborate with Toyota engineers on a method that reduced a four-hour Changeover on a thousand ton press to less than three minutes. Yes, you heard me right. Four hours to three minutes. Now, this example, as well as an excellent description of the overall SMED process was documented in a book, “A Revolution of Manufacturing: The SMED System.” So it goes without say, if you don’t already own this book, I highly encourage you to pick a copy up.

Now, in later modules, we will go into great detail as how the SMED system can lead to lightning quick Changeovers, but one thing I’d like to point out in this overview module is how much focus is placed on basic workplace, organization, and planning. In fact, it’s estimated that as much as 80% of the improvements identified by the SMED system are related to the techniques we’ve already learned about in the Gemba Academy 5S Workplace Productivity Course. So to be sure, the primary focus of Quick Changeover and SMED is most definitely not on spending money for special tooling or expensive equipment.

All right. So that’s what Quick Changeover and SMED is. Now, let’s talk a bit about the benefits of Quick Changeover and why any of us should bother with it. Well, the first reason for Quick Changeover, is that it 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. You should definitely use this increase in velocity to your advantage. In fact, you can and should use it to increase customer satisfaction and grow your business.

Another reason Quick Changeover reduces lead time is related to lot sizes. You see, when lot sizes are reduced, the lead time of the time when a customer orders a product until it’s received, is also reduced. This is because much of the lead time through a series of processes is nothing but waiting or queue time. In other words, the parts just sit and wait to be processed and moved on until the other parts in the lot are complete.

Well, let’s look at an example. Here we see a manufacturing system with three pieces of equipment: Stations one, two, and three. Let’s assume, for this example, that this particular company is plagued with long Changeovers, and as such, produces in large batches in order to better absorb the long Changeover time. Specifically, this company produces in lots of ten. Meaning, once the machine is set up and ready to go, they produce ten pieces, and then move these ten pieces to the next process.

And since the cycle time to process one part at each machine is one minute, we know it takes at least 10 minutes to get these 10 parts from Station one to Station two. Then once the 10 pieces arrive at station two, they are processed in one lot of 10 and moved to Station three. Once at Station three, these 10 parts are processed, taking another 10 minutes, until the whole lot is complete. So as a result of batching queues, the time to the first complete piece is 21 minutes, and then the time to complete the full batch is 30 minutes.

Now, let’s look at what can happen when Changeover time is reduced, enabling the company to produce at a lot size of one, also referred to as “make one, move one” or “one piece flow.” We start with the 10 pieces before Station one, but now instead of waiting for all 10 parts to be done, we make one part at Station one and then move it to Station two with no waiting. Once Station two is done, we move the single piece to Station three. A minute later, the first piece is complete, and ready for delivery.

So for those keeping score, the time to the first complete piece is three minutes, and the time to complete all 10 pieces is 12 minutes. In other words, the total lead time has been reduced by 18 minutes when compared to the Batch and Queue Method.

Next, as a result of this improved flexibility and reduced lead time, Quick Changeover also improves on-time delivery performance. Let’s look at a simple example and see why this is. Let’s say a company is plagued with an extremely long Changeover of 90 minutes, and as such, once they finally get their machines set up and ready to go, they decide to run for 360 minutes in order to absorb as much of the Changeover as possible.

Now, let’s look at what happens when this 90 minute Changeover is reduced to 30 minutes. When this occurs, the company is able to run smaller lots while also producing three different parts, which could also easily mean they are serving three different customers. In other words, the customer that orders some part Cs no longer has to wait several days for their parts like they would in the top example.

Okay, well, so far we’ve talked about how Quick Changeover improves lead time and on-time delivery. Now, let’s look at how it can lead to a dramatic reduction in inventory which reduces inventory carrying cost and increases cash flow.