Key takeaways
The six big losses are a framework from Total Productive Maintenance (TPM) that sorts equipment losses into six categories.
Each category belongs to one of the three factors of overall equipment effectiveness (OEE).
| Loss | Also called | OEE factor |
|---|---|---|
| 1. Equipment failure | Unplanned stops, breakdowns | Availability |
| 2. Setup and adjustments | Planned stops, changeovers | Availability |
| 3. Idling and minor stops | Small stops, micro stops | Performance |
| 4. Reduced speed | Slow cycles, speed loss | Performance |
| 5. Process defects | Production rejects, scrap and rework | Quality |
| 6. Reduced yield | Startup rejects | Quality |
You will see both sets of names in plants and software. They describe the same six losses.
An OEE score of 70% tells you that 30% of planned production time was not fully productive. It does not tell you why.
The six big losses answer that question, and each one points to a different kind of fix.
Without this split, a team argues about one number. With it, the team works on six specific problems.
Availability losses are stops: time when the machine was scheduled to run but did not.
Any significant stop that was not planned.
Our playbook on how to reduce machine downtime covers 15 ways to cut this loss.
Stops that were planned but still happened inside planned production time.
See our guides to SMED and reducing changeover time.
Performance losses happen while the machine is running, but producing less than it should.
Short stops below your threshold, usually cleared by the operator in seconds or a minute or two.
Our micro stops guide explains how to find them.
The machine runs, but slower than its ideal cycle time.
Not sure whether a loss is a small stop or a slow cycle? See reduced speed vs minor stops.
Quality losses are parts that were made but not right the first time.
Scrap and rework made during a stable run.
Scrap and rework made from startup until the process runs stable, most often after a changeover.
Most arguments about the six big losses are really arguments about one stop. Use the same three questions every time.
| Question | If yes | If no |
|---|---|---|
| 1. Was production planned at this time? | Go to question 2 | Not an OEE loss (it is outside planned production time) |
| 2. Was the stop longer than the short-stop threshold? | Go to question 3 | Loss 3: idling and minor stops |
| 3. Was the stop planned, such as a changeover or cleaning? | Loss 2: setup and adjustments | Loss 1: equipment failure |
Write the threshold down, for example two minutes, and give every stop longer than that a reason.
The exact number matters less than using it consistently.
For a deeper look at the boundary, read availability loss vs performance loss.
A line has 2,250 minutes of planned production time in a week (five shifts of 450 minutes). The losses were recorded automatically.
| Loss | Minutes | Share of lost time |
|---|---|---|
| 2. Setup and adjustments | 180 | 30% |
| 1. Equipment failure | 150 | 25% |
| 3. Idling and minor stops | 120 | 20% |
| 4. Reduced speed | 90 | 15% |
| 5. Process defects | 30 | 5% |
| 6. Reduced yield | 30 | 5% |
| Total lost | 600 | 100% |
The quality minutes are rejects multiplied by the ideal cycle time, which matches the count-based formula when every product has the same ideal cycle time.
Changeovers, failures and small stops cause 450 of the 600 lost minutes, or 75%.
That gives three projects: a SMED workshop, preventive tasks on the repeat failures, and a hunt for the most frequent small stops.
For a plan to work through them, see our guide on how to improve OEE.
The six big losses come from TPM and focus on equipment.
The seven wastes come from lean and focus on the whole process, such as inventory, motion and transport.
They work well together. Our comparison of the six big losses vs the seven wastes explains how.
Fabrico is a cloud-based MES and OEE platform for manufacturers, with maintenance management (CMMS) built in.
It records stops and counts from PLCs, IoT sensors and AI cameras, detects micro stops, and calculates availability, performance, quality and OEE in real time.
Downtime, MTTR and MTBF are shown by machine, so the losses are measured rather than estimated.
When a loss needs fixing, your team can open a work order or add a task to a preventive maintenance plan in the same platform, and track it to completion.
See your own losses on a live OEE dashboard: book a demo. To turn the losses into a score, read our OEE calculation guide.
Equipment failure, setup and adjustments, idling and minor stops, reduced speed, process defects and reduced yield.
The first two reduce availability, the next two reduce performance, and the last two reduce quality.
They come from Total Productive Maintenance (TPM), the improvement system developed in Japan in which OEE is a core equipment measure.
Yes. A changeover inside planned production time is loss 2, setup and adjustments, and it reduces availability.
It may be necessary, but it can almost always be made shorter.
The length of the stop. Stops shorter than your threshold count as minor stops, a performance loss.
Longer unplanned stops count as equipment failure, an availability loss.
It depends on the process. In many discrete plants, changeovers and breakdowns are large, while on fast lines small stops often dominate.
Measure all six for a few weeks before you decide.
Capture stops and counts automatically, assign a reason to every stop above your threshold, and compare output with the ideal cycle time.
Then group the minutes into the six categories and rank them.
See how Fabrico unifies OEE and maintenance in one platform.
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