AiVibeIndustry 4.0 & Manufacturing Operations
First Pass Yield (FPY)
First pass yield is the proportion of units that complete a process step correctly the first time, without rework, repair or scrap, and is a direct measure of process quality and of hidden rework effort.
FPY for a process step equals the number of units that pass the step without any rework or repair, divided by the number of units that entered it. Units that are reworked and later pass do not count as first-pass good. Rolled throughput yield, the product of the first pass yields of each step in sequence, gives the probability that a unit passes through the whole process without any defect. For example, three steps each with 95 per cent FPY give a rolled throughput yield of about 86 per cent.
Traditional final yield can look high when defects are caught and repaired along the way, concealing what is sometimes called the hidden factory of rework, retesting and repair. FPY exposes this effort and is used to target improvement in assembly, electronics testing, machining and process industries. It is closely related to the quality factor of OEE and is a common key performance indicator in lean and Six Sigma programmes.
Accurate FPY needs reliable recording of every rework and repair event, which is easier when test results and traceability data are collected automatically. Definitions must state whether retests without repair count as failures. A low FPY at a step is a starting point for root cause analysis, Pareto analysis of defect types and process capability studies.
Key points
- FPY equals units passing without rework divided by units entering the step.
- Rolled throughput yield multiplies the FPY of each step in sequence.
- Exposes the hidden factory of rework and repair.
- Closely related to the quality factor of OEE.
Where AiVibe comes in
AiVibe designs and manufactures the AiAmbA AI Factory as the OEM: edge devices plus AI agents that let people talk to PLC, CNC and robot controllers in plain language. Existing lines are retrofitted with edge devices, and a trained operator confirms every change an agent proposes.
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