Stepper drivers come in two different forms: integrated and removeable. Integrated means they are part of the board and are not installed separately; when you buy a mini Rambo, the A4892 chips are soldered directly to the board; on a classic RAMPS, the stepper driver plug into specific ports on the board. If you have separate drivers, that does mean you’ll have to source those as well as the control board if you’re building a 3D printer, however if they ever fail, you only need to replace that single driver (which is usually below $15 each) rather than desoldering a bad driver or getting an entirely new control board if you blow a driver on an integrated board (which could be $150 mistake). With removeable boards, there’s the Pololu footprint and Bigfoot footprint; Pololu is a standardized footprint, whereas Bigfoot is specifically made for Panucatt boards and to allow for more current and larger chips.
Keeping the Drivers Cool
While the stepper drivers are smart enough to shut down if they start overheating, that does mean you’re going to be skipping steps in your print. Some drivers just need a heatsink attached to the chip and call it a day, while others may need that and a fan blowing cool air onto the board.
Stealthchop and Spreadcycle
A staple of Trinamic drivers is StealthChop and Spreadcycle. Stealthchop is for quiet, low-current performance, which means your printer may be completely silent, save for the bearings rolling across the smooth rods, but it also means move too quickly, too abruptly, or snag on some tipped over supports and your 3D printer may skip steps. Spreadcycle is basically the “normal” mode and will power through and perform as you would expect. They’ve also come out with Stealthchop2 which is even better than before, so where before it may skip a step, now it can counter it with no problem at all.
On a base level, that about covers what analog stepper drivers are, how they work, and should hopefully give you an idea of what you might want in a 3D printer. If you’ve gone ahead and swapped out the stepper drivers in your 3D printer, I’d love to hear what you’ve upgraded to.