First Pass Yield & RTY for Multi-Station Manufacturing Lines
TL;DR
First Pass Yield (FPY) measures the percentage of parts passing inspection on the first attempt at a single station. Rolled Throughput Yield (RTY) is the product of all individual station FPYs across a multi-station line. Small per-station improvements compound massively: going from 95% to 99% per station improves overall yield from 77% to 95% on a 5-station line. This guide covers the formulas, station-level analysis methodology, and improvement approach.
First Pass Yield (FPY) is the percentage of parts passing inspection on the first attempt at a single station; Rolled Throughput Yield (RTY) is the product of all individual station FPYs.
First Pass Yield (FPY) measures the percentage of parts passing inspection on the first attempt, without rework or retesting.
FPY is closely related to OEE Quality but more granular — FPY is typically tracked per inspection station, while OEE Quality is at line level. For multi-station lines, you need both FPY (per station) and RTY (rolled across all stations).
FPY definition (1-sentence)
FPY = Parts Passing First Inspection ÷ Total Parts Inspected, expressed as a percentage.
Critical: “Parts Passing First Inspection” excludes anything that needed rework, retesting, or downgrades. A part that fails initial inspection but passes after rework is NOT a first-pass success.
RTY for multi-station lines
RTY = product of all individual station FPYs across a multi-station line.
Worked example. A 5-station line with 99% FPY at each station has:
RTY = 0.99⁵ = 0.951 = 95.1%
A 5-station line with 95% FPY at each station has:
RTY = 0.95⁵ = 0.774 = 77.4%
The compounding effect is dramatic. Going from 95% to 99% per station — a 4-point per-station change — improves overall yield from 77% to 95% (18-point gain).
Why per-station improvements compound
RTY is a multiplicative measure — small per-station improvements have outsized aggregate impact.
| Per-station FPY | RTY (5 stations) | RTY (10 stations) |
|---|---|---|
| 90% | 59% | 35% |
| 95% | 77% | 60% |
| 99% | 95% | 90% |
For long lines (10+ stations), the difference between 95% and 99% per station is the difference between 60% and 90% overall yield.
FPY benchmarks by industry
- Automotive OEM: median 94%, world-class 98%
- Food & beverage: median 94%, world-class 97%
- Pharma biologics: median 97%, world-class 99% (highest, GMP)
- Electronics & semiconductors: median 95%, world-class 98%
- Plastics extrusion: median 92%, world-class 96%
4-level FPY tracking maturity
- Level 1: Aggregate FPY at end of line, monthly. Useful for trends; too late for action.
- Level 2: Daily FPY at end of line with defect categories. Pareto possible; no station-level diagnosis.
- Level 3: Real-time FPY per station with defect tagging. Enables station-level RTY analysis.
- Level 4: Automated defect classification + closed-loop RCA action items.
How to improve RTY (4-step methodology)
- Measure RTY by station. Identify the worst station — typically the bottleneck for overall yield.
- Pareto defect categories at the worst station. Top 3 defect types representing 60-80% of failures.
- RCA on top 3. 5-Why or Ishikawa, action items tracked to closure.
- Verify at 30 days. If top defect dropped, move to next station. If not, RCA was incomplete.
Plants implementing structured RTY improvement typically gain 2-4 OEE points within 6 months.
Watch: How TeepTrak Customers Transform OEE
CUSTOMER PROOF
L’Oréal — OEE visibility across 15 packaging lines in 4 countries
Related guides
- Oee Explained Mid Market Guide
- Oee Quality Fpy Tracking Methodology
- Oee Formula Worked Examples
- Six Big Losses Pareto Analysis
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Frequently Asked Questions
What is First Pass Yield?
FPY is the percentage of parts that pass inspection on the first attempt, without rework or retesting. Formula: FPY = Parts Passing First Inspection / Total Parts Inspected. World-class FPY is 97-99% for most discrete manufacturing.
What is Rolled Throughput Yield (RTY)?
RTY is the product of individual station FPYs across a multi-station line. RTY = FPY1 × FPY2 × … × FPYn. RTY shows compounding effect: 5 stations at 95% each give RTY of 77.4%, much worse than individual station numbers suggest.
What is the difference between FPY and OEE Quality?
OEE Quality is calculated at line level (good parts vs total parts at end). FPY is calculated per inspection station. A 5-station line with 99% FPY at each station has overall yield of 95.1%, which is the OEE Quality.
Should rework parts count toward FPY?
No. FPY only counts parts passing inspection on first attempt. A part requiring rework is NOT first-pass yield, even if it eventually passes. Counting reworked parts hides quality problems and rework cost.
What is a good RTY for a multi-station line?
Depends on station count. For 5-station discrete: world-class RTY is 95% (requires 99% per station). For 10-station: world-class RTY is 90% (requires 99% per station). Long lines need very high per-station FPY.
How can I improve FPY quickly?
Fastest gains: (1) measure RTY per station to find worst-performing, (2) Pareto top 3 defect categories at that station, (3) structured RCA with action items. Plants typically gain 2-4 OEE points within 6 months.
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Source: TeepTrak Manufacturing Knowledge Base 2026. Benchmarks calibrated on 450+ deployments across 30 countries between 2018 and Q2 2026. Cite this guide.
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