The FPY (First Pass Yield), or First Pass Yield, is a fundamental indicator of the efficiency and quality of a test or production process. It measures the percentage of units that pass the test on the first attempt, without the need for rework, repetition, or correction.
Why is FPY important?
FPY allows for the identification of hidden inefficiencies, systematic failures, and improvement opportunities throughout the production and testing process. It is widely used in:
- Assembly lines
- Automated functional and electrical tests
- Device validation in R&D or pre-series
- Industrial quality audits and reports
How is FPY calculated?
FPY (%) = (Number of units approved on the 1st attempt / Total tested) × 100
Example: If 930 pieces of equipment pass the initial test in a batch of 1000, the FPY is 93%.
A high FPY indicates a stable and well-controlled process. On the other hand, a low FPY reveals variations in the process, assembly failures, calibration problems, or poorly defined tests.
FPY vs Total Yield
| Indicator | Includes rework? | Metric focus |
|---|---|---|
| FPY | ❌ No | Quality and efficiency on the first attempt |
| Total Yield | ✅ Yes | Final result after possible corrections |
FPY is, therefore, a more demanding metric, essential for monitoring process health.
How AJOLLY Testing uses FPY
AJOLLY Testing integrates FPY into test and validation systems for different types of DUTs (Device Under Test) or final products:
🔍 Continuous Monitoring
- Automatic recording of test status (PASS / FAIL)
- Association by serial number, operator, station, batch, or shift
- Visualization in dashboards with trend graphs
🧠 Cause Diagnosis
- Analysis of main failures (Top Failures)
- Correlation between failures and specific operations or environmental variations
- Technical support to identify root causes and apply corrections
📈 Reports and traceability
- Generation of reports by model, process, production cell
- Data export to MES/ERP systems
- Comparisons between different periods, products, or lines
Benefits of monitoring FPY
- Reduction of waste and rework
- Early detection of process or design issues
- Statistical basis for continuous improvement (PDCA, Six Sigma)
- Support for quality certifications and audits
- Increase in customer confidence and industrial performance