Abstract: The key idea of the 3D printing technology lies in the layer-by-layer printing style, where
designing the motion plan of the nozzle is a central constituent. It has at least three requirements: ①
The nozzle has to go through each voxel defining the volume of the given 3D object; ② It’s better not
to go through the same voxel multiple times; ③ The jumping from one voxel to a nonadjacent voxel
should not be encouraged, or at least the jumping gap should be as small as possible. Based on the
observations, the nozzle motion problem is transformed into the famous traveling salesman problem
and then an improved backtracking algorithm used to find the solution. Furthermore, the best
configuration of relevant parameters is given based on extensive experimental results.

Key words: 3D printing, path planning, traveling salesman problem, improved backtracking
algorithm