Additive Manufacturing (AM) is a process of joining materials to make objects from 3D model data, usually layer by layer, as opposed to subtractive manufacturing methodologies. Selective Laser Melting, commercially known as Direct Metal Laser Sintering (DMLS®), is the most diffused additive process in today’s manufacturing industry. Introduction of a DMLS® machine in a production department has remarkable effects not only on industrial design but also on production planning, for example, on machine scheduling. Scheduling for a traditional single machine can employ consolidated models. Scheduling of an AM machine presents new issues because it must consider the capability of producing different geometries, simultaneously. The aim of this paper is to provide a mathematical model for an AM/SLM machine scheduling. The complexity of the model is NP-HARD, so possible solutions must be found by metaheuristic algorithms, e.g., Genetic Algorithms. Genetic Algorithms solve sequential optimization problems by handling vectors; in the present paper, we must modify them to handle a matrix. The effectiveness of the proposed algorithms will be tested on a test case formed by a 30 Part Number production plan with a high variability in complexity, distinct due dates and low production volumes.

The purpose of this research is to investigate the impact of total JIT practices (JIT purchasing, JIT operations, and JIT selling) on operational performance (quality, delivery, and cost) of local fast-food restaurants in Jordan. The study is quantitative and covers 43 out of 142 local fast-food restaurants in Amman. Data were collected by questionnaires from 101 managers and supervisors. After confirming normality, validity, reliability, and relationships between variables, multiple regressions were conducted to test the hypothesis. Results indicate that there are strong relationships among total JIT sub-variables, very strong relationships among operational performance dimensions, and a very strong relationship between JIT and operational performance. Finally, results show that total JIT practices have a positive significant effect on the operational performance of Jordanian local fast-food restaurants.