Optimal design of variables switch-based sampling scheme for verifying Weibull distributed product lifetimes.

Ensuring products maintain their normal function during the warranty period is essential for companies to control warranty costs and sustain their brand reputation. A variables acceptance sampling (VAS) plan based on the lifetime performance index (LPI) is a practical technology for verifying product lifetimes because it can provide the number of failures required for life testing and the acceptance criterion for lot disposition. Recently, an LPI-based variables quick-switch sampling (VQSS) system has been developed to improve the sampling efficiency. The VQSS system manipulates the normal and tightened VAS plans for a series of lot dispositions. However, the existing LPI-based VQSS system only alters acceptance criteria to build normal and tightened VAS plans, which may limit its applicability. In this paper, we propose an LPI-based VQSS system with a mechanism that can alter the required number of failures. Compared to the existing LPI-based VQSS system, the proposed method has superior discriminatory power and moderate cost-effectiveness. Finally, we illustrate a lifetime verification of an electric vehicle's battery as a case study to demonstrate the practicality of the proposed method.