  In this paper, we define the 3D printing routing problem, the problem of
finding the optimal path of the nozzle in a fused deposition modeling 3D
printing system, so as to minimize the time required to create on object. We
formally model the problem with an integer linear programming formulation and
then solve it via heuristic algorithms. We test the algorithms on a set of
large-size real-life instances, comparing them with one of the most widely used
open source software for the problem. We show that large time reductions can be
obtained. We finally propose a set of interesting directions for future
research.
