What Is OEE (Overall Equipment Effectiveness)?

OEE, or Overall Equipment Effectiveness, is a composite KPI equal to availability times performance times quality: the fraction of scheduled time that produced good parts at full rated speed. It rolls three separate losses into one honest number. A machine scheduled for 8 hours, running only 6, at 80 percent of rated speed, with 5 percent scrap, scores about 57 percent.

EDGEBIC by User Solutions computes OEE in its reports from the state and piece data operators capture on the floor. This article defines the metric and shows how the three factors combine.

How It Works

OEE decomposes machine productivity into three independent questions, each answered as a fraction between zero and one.

Availability asks how much of the scheduled time the machine was actually running, rather than sitting idle or down for a breakdown or changeover. Performance asks how fast it ran while it was running, as a fraction of its rated speed, capturing minor stops and slow cycles. Quality asks what fraction of the parts it made passed inspection without rework.

Multiply the three and you get OEE. The multiplication matters, because the losses compound rather than average. Time lost to downtime cannot also make good parts, and a part made slowly that later fails inspection is wasted twice. Three respectable-looking factors of 90 percent each multiply to 73 percent, not 90, which is why OEE so often lands lower than a shop expects and why it is such a useful reality check.

A Concrete Example

Take one machine on a single day shift, scheduled for 8 hours. It actually runs for 6 of those hours; the other 2 are lost to a changeover and a short breakdown. That is an availability of 6 divided by 8, or 75 percent.

While running, it produces at 80 percent of its rated speed, held back by minor stops and slow cycles. That is a performance of 80 percent. Of the parts it makes, 5 percent are scrapped, so 95 percent pass, a quality of 95 percent.

Multiply the three: 0.75 times 0.80 times 0.95 is about 0.57, or 57 percent OEE. On paper the machine looked busy for most of the shift, but only 57 percent of its scheduled time turned into good parts at full speed. Each factor points at a different fix: availability at downtime and changeovers, performance at slow running, quality at scrap.

How EDGEBIC Uses It

OEE comes out of the shop-floor tracking, not a separate data-entry step. As operators work, they record each span of time at the kiosk as setup, run, idle, down, rework, or teardown, and good, scrap, and rework piece counts accumulate during run states. Those records supply availability from the running-versus-stopped time, quality from the good-versus-scrap counts, and, combined with rated speed, performance.

The reports roll these into OEE per machine and over time, and they also expose the three factors separately so you can see which loss dominates. That decomposition is the point: a single 57 percent number is a starting flag, but the split into availability, performance, and quality tells you exactly where to spend the improvement effort.

Each factor has its own story worth understanding on its own: availability, performance rate, and quality rate. The manufacturing glossary covers the related shop-floor terms, and what is a shop floor kiosk explains where the underlying data is captured.