Can Lowering OEE Improve Flow?

Can Lowering OEE Improve Flow?

Overall Equipment Effectiveness (OEE) is a measure of how well equipment is utilized and performing. It measures three specific aspects of running well. The first ratio is a measure of the machine’s availability – is it available to run when scheduled? The second ratio is a measure of the machine’s performance – is it producing at the expected rate? And the final ratio is a measure of the quality the machine is producing – is it making a quality product? The hypothesis is that if the equipment is available 100% of the time, producing at 100% of the expected rate, and producing 100% of the product to the quality specification, then the overall equipment effectiveness is 100%.

Many organizations measure OEE every shift and work very hard to increase the ratio. However, is there ever a case to lower OEE? Can lowering OEE improve flow?

Can Lowering OEE Improve Flow?

 Most organizations focus on availability when trying to improve OEE. Their machines can run at the correct rate and typically make a quality product. The challenge for them is reliability. The machine breaks down and is therefore not available. This is a direct hit to OEE. The other challenge for them is changeover.  If the equipment is being changed from one product specification to another, it is obviously not available to produce quality product at the expected rate. These two challenges cause organizations to sometimes make poor choices in the interest of increasing OEE.

Poor Choices for Reliability to Improve OEE

It is obvious that machines need preventative maintenance, just like cars, to run well; but many organizations choose to skip the planned maintenance procedures in the interest of maintaining a high OEE. Other organizations take an even more dangerous approach and do not include preventative maintenance time as unavailable time at the machine. They call it scheduled downtime taking the impact out of the equation.

In both cases, these approaches ignore the importance of maintaining the equipment and doing it efficiently to maximize the true Overall Effectiveness of the Equipment. In this case, lowering the OEE could improve the flow of material as the machine becomes more reliable and truly available.

Poor Choices for Changeover to Improve OEE

The goal of perfect flow is to produce a product or service one at a time, defect free, immediately at the request of the next process. Often this is in direct contradiction to the OEE measure. For a machine to achieve 100% OEE, it must produce a quality product at the expected rate and be 100% available, 100% of the time. Changing from one product or service to the next means the machine is not producing and is not available.

Consider a restaurant table. Imagine it is set-up in the morning, and then customers are seated and served, one after the other, without changing the tablecloth. Dishes are cleared as new food is delivered and silverware is brought with each dish. When one customer stands up, the next is seated and served.  It is conceivably possible, but hard to image the condition of the table by the end of the day. Undoubtedly the OEE of the table would be high, but the quality of service would certainly suffer.

In a production process, the result of no changeover is inventory. The result is mounds and mounds of the same product stacking up in the interest of not stopping to change over to another product.  In this environment, customers typically wait while inventory is built for product they do not want, while the product they do want waits in a queue behind the machine.

In this case, adding changeovers that reduce OEE will actually improve flow.

Help your organization understand the true measure of OEE. In the purest sense, improving OEE is the goal, but comes from quick changeover and reliable equipment. It does not come from skipping preventative maintenance and long production runs!

Learn more in Patrick’s book, “Facilitating Effective Change,” available online through Amazon and Barnes & Noble.

Patrick Putorti

Patrick Putorti

Patrick Putorti

Latest posts by Patrick Putorti (see all)

Speak Your Mind