Bimaterial 3D printing using galvanometer scanners

In this work a 3D printing system based on the use of stereolithography and able to print parts made of two materials is studied. The 3D printing problem is divided into two subproblems. First, the problem of locating UV light emitters capable of reaching all areas of the polymer that constitutes the part to be printed is analyzed with the goal of minimizing the number of used emitters. Next, for each layer of the part the selected emitters are assigned to the areas of the polymer to be reached, with the goals of maximizing the angle of incidence of the UV light on the printing plane and minimizing the number of emitters that need to be activated. Integer linear formulations were introduced in an earlier work for both problems. Here these models are revisited and heuristic and exact methods are developed. Finally, the formulations and methods are analyzed for a case study. The results of the computational experiments are presented and discussed.