Scheduling in a Sequence-Dependent Setup Environment at J. Kahan Company

Scheduling constitutes a major operational activity, especially from a performance and planning points of view. The complexity of a scheduling problem increases when there is a sequence-dependent aspect in which the set-up time needed to prepare the machine depends on the current and next product to be put on the machine. This is the case in J. Kahn Company, which is a leading company in Israel for developing and producing private label products. The company specializes in the development and production of powders for simple and quick preparation of foods, drinks, extractives, food colorings, syrups, and raw materials for the food and beverage industry. A major operational challenge in this industry is scheduling operations, where Kosher, Smell, Color, and Allergenic-ingredients` constraints affect the set-up time when moving from one product to another. In this plant, on average 70 jobs are to be scheduled daily on 7 mixers, which are identical in their manufacturing attributes. In order to solve this industrial problem, we employed a simulated-annealing algorithm that minimizes the sum of earliness and tardiness and which results in a near-optimal solution, compared to the current situation where it is mainly based on experience. We also formulated and solved a mathematical version of the problem. The advantages of the simulated-annealing algorithm, relatively to the mathematical programming approach, are in its run-time and the low resources needed for to obtain a solution. We compared the solution and the objective function values of both approaches and discuss other operational aspects.