oee (overall equipment effectiveness)

Overall Equipment Effectiveness (OEE) is a combined metric of availability, performance, and quality, measuring how effectively equipment produces good output. Formula: OEE = Availability × Performance × Quality. Components: (1) Availability = (Scheduled time - Downtime) / Scheduled time—accounts for equipment failures and setup; (2) Performance = (Actual output / Theoretical output) × 100—accounts for speed losses, slow cycles, minor stops; (3) Quality = Good units / Total units—accounts for defects and rework. World-class OEE: 85% overall (90% availability × 95% performance × 99% quality). Semiconductor context: OEE varies by tool type—steppers often 60-70% due to complex setup, CVD/etch tools 70-85%. Six Big Losses mapped to OEE: Availability losses (breakdowns, setup), Performance losses (idling, reduced speed), Quality losses (defects, startup yield loss). OEE improvement: identify lowest component, address specific losses using TPM (Total Productive Maintenance) methodology. OEE vs. capacity: high OEE doesn't mean high output if scheduled time is low. Tracking: automate data collection via MES integration, visualize trends, set improvement targets. Use cases: benchmark across tools, justify capital for replacement, identify improvement opportunities. OEE provides holistic view beyond simple uptime, revealing hidden capacity losses.