I have a couple of potential requirements coming up for stepper drivers, and wondered what were the current favourites within the group. I don't want to overspecify (for cost reasons), but equally don't want to invest hard earned cash on something that will disappoint! Thing is, there are so many random drivers out there, many with uncertain heritage, that it would be so easy to buy rubbish. Hence any thoughts or guidance would be brilliant!

My needs are as follows;

1). Drivers for an existing CNC router, used only for wood cutting, and based on CNC4YOU 4Nm steppers

2). Drivers for a desktop mill conversion, used for precision cutting all metals including steel, and based on 2.2Nm or 3.0Nm steppers TBD

One key question for me is - should you leave margin on the driver current rating over and above the motor's datasheet value? All the above motors are rated on their datasheets at 4.0A or 4.2A typically when wired in parallel mode. Normally I guess I'd be looking to have a driver that is rated at maybe 5A or 6A minimum, but you certainly seem to have to pay a premium for these. Or maybe the choice needs to be directed by the supply voltage you want to use? My router runs on 68v for speed, so I wonder if that might actually dictate some of the choice?

Either way, comments and suggestions would be most welcome!

Cheers
Graeme