6 Big Losses of OEE

There are 6 big losses of OEE (Overall Equipment Effectiveness).

6 Big Losses

• Breakdowns
• Setup and Minor Adjustment
• Idling and Minor Stoppages
• Reduced Speed
• Defects and Rework
• Startup Loss

Each of these losses saps a small portion of potential production you could be getting from your machines. Total productive maintenance is the tool used in Lean to deal with these losses.

Of note, there are a few different versions of the 6 big losses. Make sure that whatever you use in your company is used consistently by all.

The video below is a ‘freeview’ of the full video available at our Continuous Improvement Central.

Let’s look at each of the 6 big losses for OEE in more detail.

Breakdowns

As you might imagine, when a machine is not running, it is not producing. There are a handful of types of maintenance to prevent breakdowns. Repairs, scheduled maintenance, preventative maintenance, and predictive maintenance are the most common. Maintenance can be done by the operator or by dedicated maintenance teams.

Setup and Minor Adjustment

Setup is the process of preparing the machine to produce a part. The term is commonly used interchangeably with changeover, though some people look at setup as just one component of changeover. (For them, changeover is the process of switching from the last item of one production part to the first item of a different part.)

Setup might include something as simple as moving a stop on a fixture, or it might be purging lines and changing dies. Regardless, each second that is spent on setup is time that is not spent producing.

While setup is related to an entire run of parts, minor adjustments can also be related to individual parts. Think of cutting a stack of paper in a paper cutter. Many of them have a stop that can be used to size the paper correctly. There might be some adjustment to get the location dialed in for the first few cuts of a new size. But then, there might also be some adjustment to line up the stack of paper properly. Generally, adjustment is thought of as the machine being adjusted, but it can also entail having to adjust the part into the fixture.

Minor adjustments, even if very small, tend to break up flow.

Idling and Minor Stoppages

Idling is often a result of external factors (i.e. an operator going to get more parts), or an internal factor such as a machine running self-diagnostics.

Minor stoppages are for things like jams in a feeder or the machine stopping itself due to some sort of configuration issue. Think of your printer. You may have a jam, or you may get a popup message that the paper size is misaligned with your print job.

Reduced Speed

Reduced speed is a situation where the machine is still operational, but at a lower performance level than planned. Think of a four-engine plane with one engine out. It can still fly but would be at a slower rate than it should be.

Older machines also sometimes wear out and might not perform at peak levels. You may find that an old motor starts to vibrate too much at higher RPMs and slow it down.

Sometimes, the speed reduction is related to using poor materials that need special attention.

Basically, any factor that lets the machine still run, but not as quickly as it should, is a speed reduction.

Defects and Rework

Defects are obviously bad. There is a loss of production time when the replacement part is made, and there is often the cost of wasted materials.

There is also the issue that when a machine is considered unreliable, it is often operated differently. The operator may run it slower, check it more frequently, and inspect work. Defects, in effect, cause other types of losses as well.

Startup Loss

Startup is the time it takes to get a machine up and running. It is generally the time in the morning, or after breaks and lunches if the machine is paused temporarily.

It also covers things like warm-up times. For example, in Lean projects, you might find yourself laminating kanban cards. The time it takes from when you switch on the laminator until it is ready to go is a startup loss.

Machines “spinning up” to operating speed is also a startup loss.

Yield loss can also occur after a changeover. This is when the process of getting the machine producing again results in some bad parts as the machine is getting dialed in. As an example, you might find this situation if you have a fixture to cut pipe at a specified length. If the fixture is not well designed, it could take a few cuts to get the exact location figured out.

Essentially startup losses can be either time, which results in a lower output, or actual yield loss, which comes from defective products being produced during startup.