Do you dread having to changeover from one product to another?

Do changeovers take so long that you avoid them?

Do you find that you have to have long runs of product to avoid changeovers?

Do you have scrap when you start up a new product?

Benefits of SMED

SMED, which stands for Single Minute Exchange of Die, is a system for ensuring that every changeover from one product type to another product type with good quality can be achieved in 10 minutes or less.

It doesn’t have to involve Dies or Tooling, it can be applied anywhere that has a need to changeover from one product type to another. As such, it is often called Quick Changeover.

Philosophy of SMED

There are two very important attributes of SMED, and each one is essential for ensuring its success.

Firstly, it’s iterative. That means that it’s not a one hit wonder, it’s a series of applications of the method, each of which improves the situation.

Second, it’s Team Based. It requires a group of individuals, each with expertise which can assist the improvement, who work together to achieve the goal of quick changeover with the minimum of effort, lost time or poor quality.

How to implement SMED

There is a very particular methodology for conducting a SMED activity.

The First Discipline required is to apply the PLAN DO CHECK ACT cycle to each SMED activity.

The Second Discipline is that SMED Is Location Specific. That means that it starts with the location that the changeover happens in.

The Third Discipline is that it is Data Driven. That means measuring, timing and recording what actually happens, not what you think happens

The Fourth Discipline is to accept that when you observe an actual changeover, you will notice that something that happens when the process is stopped, could actually be safely carried out when the process is running.

This is the key to SMED

Internal Activities are any activities during a changeover that are carried out when the process has stopped.

External Activities are any activities during a changeover that are carried out when the process is running.

The key to improvement is to first see and then to identify each activity, and categorise each as Internal or External.

But don’t be fooled - some activities which are actually External are carried out when the process has stopped, and so currently appear to be Internal. The trick is to record them as they are, and then work out what they should be.

PLAN DO CHECK ACT                                                                                                                                                              

PLAN -         Observe the changeover.

                     Map out what actually happens – what, who, when, where, why, how long.

                     Identify Internal and External Activities

                     Work out and agree improvements

DO-              Document the improvements into a new trial method

                     Carry out a trial changeover using the new method

CHECK-       Use data to check the outcome – compare the old with the new

ACT-            Standardise the new method, tools, equipment and fittings

How to make SMED work - Go and do that again!

Keep doing it until the changeover from one good product type to another good product type is less than 10 minutes (or faster, if you need it to be faster).

The originator of the method suggests that each iteration of the method should aim to take 45% of the time out of the changeover. That means that each time you carry out a SMED Activity, the time should be 55% of the previous time, or less. So several iterations may be needed to hit the 10 minute mark.

If the original time was two hours:-

120 minutes to 66 minutes (SMED Activity 1)

66 Minutes to 36 minutes (SMED Activity 2)

36 minutes to 20 minutes (SMED Activity 3)

20 minutes to 11 minutes (SMED Activity 4)

11 minutes to 6 minutes (SMED Activity 5)

So 120 minutes to 6 minutes in 5 iterations. That’s 5% of the original time.

So move from making one product type to making another product type, with good quality, in less than 10 minutes.

One final thing to note. A good, efficient, effective changeover in less than 10 minutes absolutely requires that the area that the changeover occurs in is organised, efficient and effective. For that you need 5S. For information on 5S, please follow this link.