what is Six Big Losses and Their OEE Factors
The Six Big Losses is a concept commonly used in Total Productive Maintenance (TPM) to identify and categorize the most significant sources of productivity loss in manufacturing processes. These losses are grouped into six categories, each of which can be analyzed using OEE factors to identify areas for improvement. Here are the Six Big Losses along with their corresponding OEE factors:
- Equipment Failure (Breakdowns):
- OEE Factor: Availability
- OEE Factor Calculation: Availability = Operating Time / Planned Production Time
- Loss due to equipment breakdowns occurs when machinery or equipment fails unexpectedly, leading to unplanned downtime. This loss impacts Availability, as it reduces the amount of time the equipment is available for production.
- Setup and Adjustment (Changeovers):
- OEE Factor: Availability
- OEE Factor Calculation: Availability = Operating Time / Planned Production Time
- Loss due to setup and adjustment refers to the time required to change equipment settings, tools, or materials between production runs. This downtime reduces Availability as the equipment is not actively producing during setup and adjustment periods.
- Idling and Minor Stoppages:
- OEE Factor: Availability
- OEE Factor Calculation: Availability = Operating Time / Planned Production Time
- Loss due to idling and minor stoppages occurs when equipment is not running at full capacity due to small interruptions or short stoppages. These interruptions reduce Availability as they result in periods of downtime, albeit brief ones.
- Reduced Speed (Slow Running):
- OEE Factor: Performance
- OEE Factor Calculation: Performance = (Ideal Cycle Time * Total Count) / Operating Time
- Loss due to reduced speed occurs when equipment operates at a slower rate than its maximum potential speed. This loss affects Performance, as it reduces the rate at which products are produced compared to ideal cycle time.
- Process Defects:
- OEE Factor: Quality
- OEE Factor Calculation: Quality = Good Count / Total Count
- Loss due to process defects occurs when products are produced that do not meet quality standards and require rework, repair, or scrap. This loss affects Quality, as it reduces the percentage of defect-free products produced compared to the total production output.
- Start-up and Yield Losses:
- OEE Factors: Availability, Performance, Quality
- OEE Factor Calculations: Availability = Operating Time / Planned Production Time; Performance = (Ideal Cycle Time * Total Count) / Operating Time; Quality = Good Count / Total Count
- Loss due to start-up and yield losses encompasses various inefficiencies and losses that occur during the startup phase of production runs and during yield losses, which involve production losses due to raw material defects or other factors. These losses can impact Availability, Performance, and Quality, depending on the specific circumstances.
By categorizing productivity losses into these Six Big Losses and analyzing them using OEE factors, manufacturing organizations can identify opportunities for improvement and implement targeted strategies to maximize overall equipment effectiveness and productivity.