1. If your motors have 4 wires, then you have no choice but bipolar.
2. If it has 6 wires, you could go either way, but bipolar would give you no advantage over unipolar.
3. If it has 8 wires, bipolar would likely give you 40% more low speed torque if you wire your motors coils in parallel.
For a small, low friction engraving machine like that, torque is really not an issue. I would select the drive that can handle the highest voltage in order to get the most speed. |