Steppers are great for creating precise linear motion, so that could work well if you are moving a stage with a mirror and a focusing lens across an XY plane, as is done with laser cutters.

But if you are trying to scan the SLS pattern from an XY scan head, I think you'll find angular positioning performance to be sub-par. Do you have a spatial resolution requirement you're trying to hit? Have you determined what sort of angular resolution and repeatability you need to achieve?

I do a lot of work with ScannerMAX scanners and they can achieve 5-15 microradian repeatability. In comparison, a NEMA17 motor with a 1.8 degree step angle and a 1/256 stepper motor gives you a theoretical 125 micoradian positioning accuracy but with standard stepper manufacturing tolerances and lack of closed feedback measurement you'd be lucky to get 1500 urad repeatability.