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OEE Implementation Guide
for Tennessee Manufacturers
What OEE measures, how to calculate it, where to start, and how to use it to drive real improvement on the shop floor.
Why OEE Matters
Most manufacturers know they have equipment losses. Machines go down, lines run slower than they should, and scrap happens. The problem is not awareness, it is measurement. Without a structured way to quantify these losses, improvement efforts are based on gut feel rather than data.
OEE gives you a single number that captures three critical dimensions of equipment performance. It is not just a maintenance metric. It connects equipment performance to output, delivery, cost, and customer satisfaction.
Availability
Is the machine running when it is scheduled to?
Breakdowns, changeovers, material shortages, unplanned stops.
Performance
Is it running at full rated speed while it runs?
Slow cycles, minor stops, speed losses, operator hesitation.
Quality
Is it making good parts the first time through?
Scrap, rework, startup rejects, out-of-spec product.
How to Calculate OEE
OEE is the product of three percentages, each calculated independently then multiplied together.
OEE = Availability × Performance × Quality
Availability = Run Time ÷ Planned Production Time
Example: a 480 minute shift minus 30 minutes of breaks leaves 450 minutes planned. The machine was down 60 minutes, so run time is 390 minutes. Availability = 390 ÷ 450 = 86.7%.
Performance = (Ideal Cycle Time × Total Pieces) ÷ Run Time
Example: ideal speed is 2 pieces per minute. In 390 minutes of run time the machine produced 700 pieces, where ideal would be 780. Performance = 700 ÷ 780 = 89.7%.
Quality = Good Pieces ÷ Total Pieces
Example: of 700 pieces produced, 21 were defective. Good pieces = 679. Quality = 679 ÷ 700 = 97.0%.
Final OEE = 86.7% × 89.7% × 97.0% = 75.4%
This manufacturer is losing nearly a quarter of productive capacity, and the calculation shows exactly where it comes from.
OEE Benchmarks
The most important comparison is always your own trend over time.
85% and above — World Class
Mature TPM, standardized work, and sustained discipline across all three factors.
65 to 85% — Good
A solid foundation with room for targeted improvement.
45 to 65% — Typical
A common starting point with significant improvement opportunity.
Below 45% — Low
More than half of productive capacity is being lost.
Do not chase a number. OEE is a tool for finding losses, not a scorecard to game.
The Six Big Losses
Understanding which losses are hurting you most tells you which lean tools to deploy first.
| Loss | Description | Lean Tool |
|---|---|---|
| Availability Losses | ||
| Breakdowns | Unplanned equipment failures | TPM |
| Changeover | Time switching between products | SMED |
| Performance Losses | ||
| Minor Stops | Short stops under five minutes | 5S, Standardized Work |
| Slow Cycles | Running below designed speed | TPM, Standardized Work |
| Quality Losses | ||
| Startup Rejects | Defects after changeover warmup | SMED, Poka-Yoke |
| Production Rejects | Defects during normal production | Poka-Yoke, Standardized Work |
How to Start Tracking OEE
You do not need software, sensors, or a six month project. Start simple, on paper, on one machine.
Step One
Pick one machine
Choose a bottleneck or a line everyone knows is underperforming. One machine, one shift, one week.
Step Two
Define your terms
Agree on planned production time, ideal cycle time, what counts as a good part, and what counts as downtime. Write it down.
Step Three
Collect data for one shift
Use a paper log at the machine. Record all downtime events with reason and duration, total pieces, and defective pieces.
Step Four
Calculate and review
Calculate Availability, Performance, and Quality daily for one week. Review with the team: where are we losing the most?
Step Five
Act on what you find
Availability losses point to TPM and SMED. Performance losses point to standardized work. Quality losses point to mistake proofing.
Common OEE Mistakes
OEE is simple to calculate but easy to get wrong.
Inflating ideal cycle time
Using your average speed instead of your best sustainable speed hides performance losses. Use the machine's rated or best observed speed.
Hiding planned stops
Reclassifying unplanned downtime as planned stops inflates Availability. If a changeover took 45 minutes but should take 15, those 30 extra minutes are a loss.
Not tracking minor stops
Twenty two-minute stops per shift adds up to 40 minutes of lost production. Minor stops go unrecorded but accumulate fast.
Making OEE punitive
If operators feel punished for low OEE, they stop reporting accurately. The question is always: what is preventing this machine from running at its best?
Measuring everything at once
Starting OEE on every machine across three shifts overwhelms the team. Start with one machine, prove the value, then expand.
Never acting on the data
Tracking OEE without making improvements is just extra paperwork. Every week, identify your biggest loss and decide what to do about it.
Free Resource
OEE Tracking Sheet
A ready-to-print daily data collection workbook designed for use at the machine, plus guidance on setting up OEE tracking in your facility. It includes a daily shift log template, downtime reason codes, an OEE calculation worksheet, and a weekly trend chart.
Request the OEE Tracking WorkBookt →
A Solutions Consultant will send it to you directly.
Free Resource
OEE Implementation Guide, PDF
The full Implementation Guide as a print-ready PDF, formatted for sharing with your team or keeping at the line. The same material covered on this page, in a single document you can reference offline.
Request the OEE Guide in PDF →
A Solutions Consultant will send it to you directly.
Common Questions About OEE
What is OEE in manufacturing? +
OEE, or Overall Equipment Effectiveness, measures how effectively a piece of manufacturing equipment is being used. It combines three factors: Availability, whether the machine is running when scheduled; Performance, whether it is running at full speed; and Quality, whether it is producing good parts. A score of 100% means zero downtime, full speed, and zero defects.
How do you calculate OEE? +
OEE = Availability × Performance × Quality. Availability is Run Time divided by Planned Production Time. Performance is Ideal Cycle Time times Total Pieces divided by Run Time. Quality is Good Pieces divided by Total Pieces.
What is a good OEE score? +
85% or higher is considered world class. 65 to 85% is good. 45 to 65% is a typical starting point. Below 45% indicates significant opportunity. The most important comparison is always against your own previous performance.
What are the Six Big Losses? +
The Six Big Losses are breakdowns, setup and changeover (Availability losses), minor stops, slow cycles (Performance losses), startup rejects, and production rejects (Quality losses). Each maps to specific lean tools: TPM for breakdowns, SMED for changeovers, 5S and standardized work for minor stops, and mistake proofing for quality defects.
How do I start tracking OEE? +
Pick one machine on one shift. Define your terms: planned production time, ideal cycle time, and what counts as a good part. Use a paper log to record downtime, total pieces, and defective pieces. Calculate daily for one week, then review with your team to find the biggest loss.
Need Help Setting Up OEE Tracking?
Tennessee MEP consultants help manufacturers set up OEE tracking and implement the lean tools that improve it. Every engagement begins with an in-plant walkthrough at no cost.