The Six Big Losses — Pareto Analysis Framework for Manufacturing

The Six Big Losses framework categorizes every cause of manufacturing productivity loss into six categories, each mapped to one of the three OEE pillars (Availability, Performance, Quality).

Combined with Pareto analysis, the framework reveals which losses to attack first for maximum impact. This guide covers each loss with concrete data, typical magnitude, and the Pareto methodology to prioritize countermeasures.

The 6 losses — 1-line summary each

Availability losses (machine not running):

1. Equipment breakdowns — unplanned mechanical/electrical failures
2. Setup & adjustments — changeovers between products

Performance losses (machine running below ideal):

3. Idling & minor stops — brief stoppages under 5 minutes
4. Reduced speed — sustained underspeed below ideal cycle

Quality losses (bad parts):

5. Process defects — bad parts during steady-state operation
6. Reduced yield — bad parts during startup/changeover

Loss 1 — Equipment breakdowns

Definition: Unplanned equipment failures that stop production. Mechanical failures, electrical failures, control system errors, sensor failures.

Typical magnitude: 5-15% Availability loss in mid-market plants. Largest hidden source of OEE loss in plants without real-time tracking.

Reduction approach: real-time downtime tracking + weekly Pareto + predictive maintenance triggers + cross-trained first-response.

Loss 2 — Setup & adjustments

Definition: Time lost during product changeovers — from “last good part of A” to “first good part of B”.

Typical magnitude: 5-25% Availability loss for high-SKU mix plants; 1-5% for stable production.

Reduction approach: SMED (Single-Minute Exchange of Die) — separate internal vs external setup activities, convert internal to external. Typical gain: 50-80% reduction in 6 months.

Loss 3 — Idling & minor stops

Definition: Brief stoppages under 5 minutes — jams, sensor faults, brief operator interventions.

Typical magnitude: 5-10% Performance loss. Often the LARGEST hidden source of OEE loss because operators don’t report stops under 5 minutes.

Reduction approach: automatic micro-stop detection (impossible without real-time monitoring) + Pareto on top 3 micro-stop categories.

Loss 4 — Reduced speed

Definition: Equipment running below ideal cycle time (intentional or unintentional).

Typical magnitude: 5-15% Performance loss. Almost always invisible without comparing actual vs ideal cycle time at sub-second granularity.

Reduction approach: document demonstrated best cycle time per product + real-time speed deviation alerts.

Loss 5 — Process defects

Definition: Bad parts produced during steady-state operation (not startup). Includes scrap and rework.

Typical magnitude: 1-5% Quality loss for mature plants; 5-15% for plants with poor process control.

Reduction approach: real-time defect tagging + mandatory RCA on top 3 categories.

Loss 6 — Reduced yield (startup losses)

Definition: Bad parts produced during equipment startup or after changeovers.

Typical magnitude: 1-3% Quality loss for stable plants; 5-10% for high-changeover plants (pharma, semiconductors).

Reduction approach: standardize startup procedures, capture/replay successful parameters.

How to apply Pareto analysis to the Six Losses

The Pareto principle holds in manufacturing: 20% of stop causes account for 80% of downtime minutes.

Standard Pareto methodology:

1. Capture every stop with timestamp + standardized cause code (real-time, not end-of-shift)
2. Aggregate weekly by cause category — minutes not events
3. Rank top 5 causes by total minutes lost
4. Attack top cause first — the largest single category typically accounts for 30-50% of total loss
5. Validate at 12 weeks — if top cause reduced 30%, move to second; if not, RCA was incomplete

Plants applying Pareto-driven Six Big Losses reduction typically gain +6 to +12 OEE points within 12 months.

Watch: How TeepTrak Customers Transform OEE

Related guides

• Oee Explained Mid Market Guide
• Oee Availability Improvement Tactics
• Oee Performance Microstops Detection
• Manufacturing Downtime Cost Categorization

Frequently Asked Questions

What are the Six Big Losses in manufacturing?

The Six Big Losses are: (1) Equipment breakdowns, (2) Setup and adjustments, (3) Idling and minor stops, (4) Reduced speed, (5) Process defects, (6) Reduced yield/startup losses. Defined by Seiichi Nakajima as part of TPM (Total Productive Maintenance).

Which of the Six Big Losses is biggest?

Varies by sector. In automotive: equipment breakdowns (5-15% Availability loss). In food and beverage: changeovers (Loss 2). In plastics: idling and minor stops (Loss 3). Pareto analysis on real-time data identifies your specific pattern.

How does Pareto analysis work for OEE improvement?

20% of stop causes account for 80% of downtime minutes. Pareto methodology: capture every stop with cause code in real-time, aggregate weekly by minutes, rank top 5 causes, attack the largest first. Validate at 12 weeks before moving to the next cause.

Why are micro-stops the largest hidden loss?

Micro-stops under 5 minutes are 3-5x more frequent than breakdowns but operators don’t log them. Manual paper-based tracking misses 100% of micro-stops. Real-time IoT-based monitoring captures every stop including those under 60 seconds.

How long does Six Big Losses reduction take?

Plants applying Pareto-driven Six Big Losses reduction typically gain +6 to +12 OEE points within 12 months. Single largest cause typically reduces 30-50% in the first 90 days; full plant transformation takes 18-24 months.

How are the Six Losses related to OEE?

Each loss maps to one of the three OEE pillars. Losses 1-2 (breakdowns, setups) reduce Availability. Losses 3-4 (minor stops, speed) reduce Performance. Losses 5-6 (defects, startup) reduce Quality. Improving OEE always means reducing one or more losses.