Advanced Process and Production Planning for Machine Layout Optimization in Press Brakes

Bending is a forming process that allows the production of complex sheet metal components through the combination of simple straight bends that are produced with generic tools. As a result of the generic nature of the tools, the process is especially suitable for the production of small batches with high variability. Nevertheless, in such a scenario, changeover time potentially increases if optimal process and production planning decisions are not respected. To reduce the changeover time at the press brake and increase the productivity of workshops, this dissertation proposes several advanced process and production planning algorithms that go beyond the current state-of-the-art in literature and industry.

Given a part with a pre-determined bend sequence, the first chapters introduce a novel machine layout algorithm that determines the shortest machine layout that allows the production of the given part with minimum number of tool stations and segments. To ensure the industrial applicability of the developed algorithm, great attention is paid to the identification and modelling of all kinds of elements and constraints arising from the bending manufacturing process.

Whereas the scope of the first chapters is the optimization of the machine layout for the production of a single part, the remaining chapters address the problem of determining the sequence and composition of the machine layouts that allow the production of a set of parts with minimum changeover time at the press brake. For the latter purpose, two main problems are distinguished: the minimization of tool changes and the minimization of time-consuming repositioning operations. For the first problem, a novel integrated process and production planning framework is developed to implicitly consider the full spectrum of feasible machine layouts per part during production planning. For the second problem, several exact and heuristic algorithms are developed to define the arrangement of the tool segments leading to the lowest number of time-consuming repositioning operations being required between consecutive machine layouts for the adjustment of the location of reused segments.