Sinem OzkanOnder Bulut2025-10-0620222146-09572146-570310.11121/ijocta.2022.1034http://dx.doi.org/10.11121/ijocta.2022.1034https://gcris.yasar.edu.tr/handle/123456789/6367We consider a make-to-stock environment with a single production unit that corresponds to a single machine or a line. Production and hence inventory are controlled by the two-critical-number policy. Production times are independent and identically distributed general random variables and demands are generated according to a stationary Poisson process. We model this production-inventory system as an M/G/1 make-to-stock queue. The main contribution of the study is to extend the control of make-to-stock literature by considering general production times lost sales and fixed production costs at the same time. We characterize the long-run behaviour of the system and also propose a simple but very effective approximation to calculate the control parameters of the two-critical-number policy. An extensive numerical study exhibits the effects of the production time distribution and the system parameters on the policy control levels and average system cost.EnglishProduction, Make-to-stock, Production and inventory control, Queueing theory, Renewal theoryPRODUCTION-INVENTORY SYSTEMS, APPROXIMATIONS, POLICY, MODEL, DEMANDArticle