Optimal Production Run Length Research Articles

Economic production cycles and setup reduction in an imperfect production system

This paper considers an economic production quantity model with imperfect production processes where the setup cost is function of capital expenditure. The mathematical model is derived to determine the optimal production run length and investment in setup cost reduction such that the total cost per unit time is minimized. In addition, an efficient algorithm is provided to find the optimal production run length and setup cost. A numerical example is provided to illustrate the results and to assess the cost savings realized by adopting investment strategy. Furthermore, some managerial implications are also included.

Optimal production run length and capital investment in quality improvement with an imperfect production process

The paper studies the effects of an imperfect production process on the optimal production run length when capital investment in process quality improvement is adopted. The mathematical model is derived to determine the optimal production run length and capital investment under the assumption of logarithmic investment function such that the total annual cost is minimized. In addition, an efficient algorithm is provided to find both the optimal production run length and the optimal process quality. Therefore, the optimal lot sizing and capital investment are appropriately determined. A numerical example is provided to illustrate the results and to assess the cost savings realized by adopting capital investment. Furthermore, some managerial implications are also included.

The impact of a free-repair warranty policy on EMQ model for imperfect production systems

In this study, the economic production quantity problem in the presence of imperfect processes for products sold under a free-repair warranty policy is considered. In the literature, that a production facility may deteriorate with time is assumed, and the time to shift from an in-control state to an out-of-control state is assumed to be exponentially distributed, i.e., the process failure rate is a constant. However, in many practical situations, the process possesses an increasing failure rate due to cumulative wear in producing items. This study is extended to consider a process subjected to random deterioration from an in-control state to an out-of-control state with a general shift distribution. A mathematical model representing the expected total cost per item is developed to determine the optimal production policy. The objective here is to obtain the optimal production run-length (lot size) so that the expected total cost per item is minimized. Different conditions for optimality, properties, and bounds on the optimal production run-length are provided. A numerical example is used to see the adequacy of using the exponential distribution when the actual distribution is Weibull with an increasing failure rate.

Optimal production run length and inspection schedules in a deteriorating production process

This paper presents an economic manufacturing quantity model which determines an optimal production run length and inspection schedules simultaneously in a deteriorating production process. It is assumed that a production process is subject to a random deterioration from the in-control state to the out-of-control state and, thus, produces some proportion of defective items. An optimal production run length and an optimal number of inspections are derived, and unique properties of the proposed model are discussed. A numerical experiment is carried out to examine the behavior of the proposed model and compare the proposed model to an existing model.

Optimal production run length and inspection schedules in a deteriorating production process

This paper presents an economic manufacturing quantity model which determines an optimal production run length and inspection schedules simultaneously in a deteriorating production process. It is assumed that a production process is subject to a random deterioration from the in-control state to the out-of-control state and, thus, produces some proportion of defective items. An optimal production run length and an optimal number of inspections are derived, and unique properties of the proposed model are discussed. A numerical experiment is carried out to examine the behavior of the proposed model and compare the proposed model to an existing model.

Optimal production run length for products sold with warranty

This article studies the optimal production run length for a deteriorating production system in which the products are sold with free minimal repair warranty. The deterioration process of the system is characterized by a two-state continuous-time Markov chain. For products sold with free minimal repair warranty, we show that there exists a unique optimal production run length such that the expected total cost per item is minimized. Since there is no closed form expression for the optimal production run length, an approximate solution is derived. In addition, three special cases which provide bounds for searching the optimal production run length are investigated and some sensitivity analysis is carried out to study the effects of the model parameters on the optimal production run length. Finally, a numerical example is given to evaluate the performance of the optimal production run length.

An optimal production run length in deteriorating production processes

This paper presents an EMQ model which determines an optimal production run length in a deteriorating production process. It is assumed that the process is subject to a random deterioration from an in-control state to an out-of-control state with an arbitrary distribution and, thus, produces some proportion of defective items. An optimal production run length and a minimum average cost are derived in three deteriorating processes: constant, linearly increasing, and exponentially increasing. Several different results from those of previous research are obtained and discussed. A numerical experiment is carried out to see the behavior of the proposed model depending on the cost and process parameters. Some interesting behaviors are observed.