A decision-support model for EOL test industrialization during ECU production ramp-up

Abstract Production ramp-up requires timely decisions on when flexible engineering resources should be replaced or complemented by production-intent processes. In manufacturing test systems, this transition is particularly critical because starting industrialized end-of-line (EOL) testing too early increases rework under unstable product definitions, whereas starting too late can constrain ramp-up readiness and increase post-SOP support effort. This paper presents an integrated decision-support formulation for comparing candidate start times for the transition from flexible test-bench (TB) testing to EOL test-process industrialization. The model links time-dependent functional-test demand, project-level software maturity/release-stage changes, latent EOL readiness, manual TB capacity, a pre-SOP readiness gate, and normalized cost; project phases are used only to parameterize and label the industrial case study. The formulation is evaluated retrospectively using anonymized weekly data from two electronic control unit programs. Among four pre-defined phase-aligned planning benchmarks, the mid-C1 benchmark has the lowest baseline penalized normalized cost. A complementary weekly start-time scan identifies project week 59, still within C1, as the baseline model minimum while satisfying the readiness requirement at the gate. Sensitivity and switching-point analyses show that the preferred phase-aligned benchmark changes toward C2 when readiness develops sufficiently faster, the required readiness is reduced, or the late-readiness penalty is weakened. The study therefore supports a conditional timing trade-off between release-driven EOL rework, manual TB resource pressure, and late-readiness risk rather than a universal phase prescription or an independently validated predictive optimum.