Six Big Losses

Introduction: Six Big Losses

The Six Big Losses are the main categories of equipment inefficiency that reduce Overall Equipment Effectiveness (OEE) and productivity in manufacturing. They are a central concept in Total Productive Maintenance (TPM), helping teams identify, measure, and eliminate the causes of waste and downtime.

Background

Developed as part of the TPM framework in Japan, the Six Big Losses originated from the need to improve equipment reliability and operational efficiency. They provide a structured way to analyse production problems that prevent machines from running at their full potential. The concept connects directly to the three OEE factors: Availability, Performance, and Quality.

Key Elements/Features

The Six Big Losses are divided according to the OEE categories:

• Availability Losses:
  1. Equipment Failures (Breakdowns): Unexpected stoppages caused by machine faults or wear.
  2. Setup and Adjustments: Time lost during changeovers, calibrations, or setting corrections.
• Performance Losses:
  3. Idling and Minor Stops: Short, frequent interruptions caused by jams, sensor faults, or material flow issues.
  4. Reduced Speed: Operating below the machine’s designed speed due to suboptimal settings or deterioration.
• Quality Losses:
  5. Process Defects: Scrap or rework caused during steady-state production.
  6. Reduced Yield (Startup Losses): Defective output produced during machine warm-up or initial startup.

Applications/Examples

The Six Big Losses are applied in OEE analysis, Kaizen projects, and TPM initiatives to identify root causes of inefficiency. For example, a packaging line may show high performance losses due to frequent microstops, or a bottling plant might focus on reducing setup losses through SMED (Single-Minute Exchange of Dies).

Relevance/Impact

By addressing the Six Big Losses, organisations can significantly increase OEE, improve equipment reliability, and strengthen continuous improvement culture. This framework creates shared ownership between operators and maintenance teams, forming a foundation for world-class manufacturing performance.

See also

• Total Productive Maintenance (TPM)
• Overall Equipment Effectiveness (OEE)
• SMED (Single-Minute Exchange of Dies)
• Quick Change-over