How to turn off microstepping for pellet extruders

Pellet extruders (20:1 steppers) does not work properly above 1/8 step. How to turn off microstepping in Smoothie?

Smoothieboard ties all MS1/MS2 to a single set of jumpers that configures the same microstepping for all axes. Therefore, this cannot be configured in hardware and the only ways to accomplish this task are to substitute an external driver for the stepper axis or to make modifications to the board.

My choice would be to substitute an external driver; it’s cheap and reversible if you change your mind later.

However, according to these schematics:

…you can cut JP30 and JP31 and bodge-wire MS1 and MS2 to any GND source to pull them low to change all axes to full stepping. If you want to do that for only one axis, you’ll have to cut that axis’s MS1 and MS2 traces and bodge MS1 and MS2 pins on that axis’s stepper controller to GND.

If you want ⅛ stepping, you can’t do it with the A4982 controllers on the smoothieboard, but if you pull only MS1 to GND and leave MS2 high (you can trace from JP31 for MS1) you’ll get ¼ stepping for the affected axis/axes.

See page six of the A4982 datasheet

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I agree, I’d definitely use a $10 TB6600 just for the pellet extruder, it’s going to be the easiest solution here.

I find it very strange you couldn’t use 1:32 microstepping though, why is this?

1:32 microstepping has less than 5% of the holding torque of full stepping.

It’s being tested by recycl3dprint on Marlin so wait for final conclusions. They are getting very good results with nozzles 2-3mm. My first prints were very bad. Trying to find good settings.

I have helped several companies use Smoothieboard with pellet extruders, and no issue about microstepping or holding torque has ever come up.
Considering the mechanics involved, I really don’t see how this could matter. I suspect they simply don’t know why this is going wrong and they gave you an excuse without being sure it’s actually the issue.

I’m actually shopping for a pellet extruder myself, mind telling me where you got yours so I can add a note about this in my sourcing list ? :slight_smile:

Information comes from beta testers (not manufacturer) and now checking.

Can you make a list of current pellet extruder makers? Mahor, Direct3D, Wasp, Pollet, Atlas… usually they don’t sell to DIY.