When set-up times or set-up costs are related to a production process, lot-sizing is relevant. For example, if a divers set of drink variants is filled by the same filling system a product change usually requires a new set-up process which often takes longer than one hour.
Lot-sizing issues are often dependent on the abilities of a specific production segment in which they occur. Lot-sizing problems of a small quantity but high variety workshop production are different from issues in variety production. There, production orders utilize a production system for some weeks. Workshop production requires a planning horizon that is divided into long planning periods (macro-period model). Whereas in variety production time is either modeled continuously or the horizon is divided into very small planning periods (micro-period model). We develop appropriate solution approaches that are based on practical-orientated models for lot-sizing problems.
Another research focus is the development of optimization methods for lot-sizing issues if demand is dynamic and stochastic (stochastic lot-sizing problems).