Economic production quantity for two-stage imperfect production system with random machine unavailability and learning effect

摘要

This article studies the learning effect of the unit production time for a two-stage imperfect production system with machine unavailability. The production rates are finite; preventive maintenance of unreliable machines follows some stochastic processes with known probability distributions. Due to different preventive maintenance times for two stages, two cases for shortage cost are investigated, and two cost-minimization models are formulated. The total cost includes production cost, shortage cost, rework cost, maintenance cost and inventory carrying cost. Numerical examples are provided to illustrate the proposed models.