Functional Test Fixtures Owned by the Factory or the Buyer
Buyer-owned test fixtures require explicit PO line items, complete source files, and calibrated limit audits to prevent factory lock-in.
Defect Escape
Inspection Failure
Quality benchmarks determine whether a manufacturing process successfully contains all errors within the factory floor. A defect escape occurs when a failure in inspection allows a non-functional or out-of-tolerance board to be shipped to the client. This event indicates that the existing test coverage was either bypassed or insufficient to catch a specific soldering or component error.
It is measured at the point of customer receipt and ends when the fault is formally logged in the return system.
Detection Analysis
Identifying why a fault was missed involves reviewing the automated optical inspection logs and the functional test results. When a defect escape is confirmed, the engineering team must determine if the fault was visible but ignored or if the test program lacked the sensitivity to detect it. This analysis often reveals gaps in the test plan, such as a missing boundary scan or an inadequate visual inspection check.
By tracing the serial number back to the specific production lot, the facility can check if other boards in the same batch share the same problem. This process prevents a single oversight from becoming a systemic quality crisis across an entire product line.
Process Resolution
Improvements to the manufacturing flow usually follow the discovery of a shipped error. To prevent a future defect escape, the factory may add new inspection stages or tighten the tolerances on existing testers. These changes ensure that the factory output meets the required reliability standards.