Calculate and diagnose Overall Equipment Effectiveness (OEE) by decomposing into Availability, Performance, and Quality rates. Use this skill when the user needs to measure production line efficiency, identify equipment losses, benchmark manufacturing performance, or justify capital investment — even if they say 'why is our output low', 'machine utilization report', 'production efficiency', or 'how much capacity are we losing'.
IRON LAW: OEE = Availability × Performance × Quality
OEE is a MULTIPLICATIVE metric. 90% × 90% × 90% = 72.9%, not 90%.
Each factor compounds the loss. World-class OEE is 85%+. Most plants
operate at 60-65%. Knowing the TOTAL is useless — you must decompose
to find which factor is dragging performance down.
| Factor | Formula | Measures | Loss Categories |
|---|---|---|---|
| Availability | Run Time / Planned Production Time | Uptime vs downtime | Equipment failures, changeovers, material shortages |
| Performance | (Ideal Cycle Time × Total Count) / Run Time | Actual speed vs design speed | Minor stops, slow running, idling |
| Quality |
| Good Count / Total Count |
| Yield, first-pass quality |
| Defects, rework, scrap, startup rejects |
| Loss | OEE Factor | Example |
|---|---|---|
| 1. Equipment failure | Availability | Machine breakdown, unplanned repair |
| 2. Setup & changeover | Availability | Product changeover, die change, cleaning |
| 3. Idling & minor stops | Performance | Sensor blockage, jam clearing, small adjustments |
| 4. Reduced speed | Performance | Running below rated speed due to wear or material |
| 5. Process defects | Quality | In-process rejects, rework |
| 6. Startup rejects | Quality | Scrap during warm-up, first-article failures |
Planned Production Time: 480 min (8-hour shift)
Downtime (breakdowns + changeover): 60 min
Run Time: 420 min
Ideal Cycle Time: 1 min/unit
Total Units Produced: 380
Good Units: 360
Defective Units: 20
Availability = 420 / 480 = 87.5%
Performance = (1 × 380) / 420 = 90.5%
Quality = 360 / 380 = 94.7%
OEE = 87.5% × 90.5% × 94.7% = 75.0%
Phase 1: Calculate OEE for each production line/machine Phase 2: Identify the weakest factor (Availability, Performance, or Quality) Phase 3: Pareto the losses within that factor (which specific loss is biggest?) Phase 4: Root cause analysis on the top loss (5 Whys, fishbone) Phase 5: Improve and remeasure
| OEE Level | Rating | Typical |
|---|---|---|
| > 85% | World-class | Top manufacturers |
| 60-85% | Typical | Room for improvement |
| 40-60% | Low | Significant losses, urgent action needed |
| < 40% | Critical | Equipment or process fundamentally broken |
# OEE Report: {Production Line}
## OEE Summary
| Factor | Value | Benchmark | Status |
|--------|-------|-----------|--------|
| Availability | {%} | >90% | 🟢/🟡/🔴 |
| Performance | {%} | >95% | 🟢/🟡/🔴 |
| Quality | {%} | >99% | 🟢/🟡/🔴 |
| **OEE** | **{%}** | **>85%** | 🟢/🟡/🔴 |
## Loss Breakdown
| Loss | Minutes Lost | % of Total Loss | Priority |
|------|-------------|----------------|---------|
| {loss type} | {min} | {%} | 1/2/3 |
## Root Cause (Top Loss)
{5 Whys or fishbone analysis}
## Improvement Plan
| Action | Target Impact | Timeline | Owner |
|--------|-------------|----------|-------|
| {action} | +{X%} OEE | {weeks} | {who} |
references/tpm.mdreferences/oee-automation.md