Lot Tolerance Percent Defective
Meaning ~ Lot tolerance percent defective establishes the maximum percentage of defects allowed in an isolated batch for it to be accepted at a low consumer risk level.
Latent Defect Discovery
Meaning
Product failures sometimes emerge only after extended use or exposure to specific environmental stressors. Latent defect discovery is the identification of a flaw that was present at the time of manufacture but could not be found through reasonable inspection at the point of delivery. It represents a significant risk for manufacturers because it bypasses the standard quality gates at the factory.
This type of defect is the most common cause of long term warranty claims and large scale product recalls.
Temporal Delay
The time between the shipment of the goods and the appearance of the problem can span months or years. Unlike a visible scratch or a missing part, a latent defect discovery often involves material fatigue or chemical instability. A battery that passes all initial voltage tests but fails after fifty charge cycles is a classic example.
This delay makes it difficult to trace the root cause back to a specific batch or raw material supplier.
Identification Process
Finding these hidden flaws usually requires destructive testing or long term life cycle simulation. In most trade laws, the buyer has a longer window to report a latent defect discovery than a visible one. The burden of proof often sits with the buyer to show that the flaw was inherent to the product and not caused by misuse.
Expert forensic analysis is frequently needed to determine exactly when and why the failure began.
Warranty Activation
Contracts must explicitly address who pays when these hidden issues come to light. A latent defect discovery often triggers the long term warranty clauses rather than the immediate rejection rights found in the purchase order. Suppliers may be required to cover not just the cost of the replacement part but also the labor and shipping costs associated with the repair.
Robust quality records are the only defense a factory has against claims that a flaw was systemic.
Non-Conformance Report
Meaning ~ Documentation instrument detailing specific deviations from technical or contractual standards during production to control resolution paths and costs.