Build Your Own SLA/SLS

Hi all,

I'm working on tuning my z axis movement and am running into a snag.

I'm using the standard RAMPS 1.4 kit with the Pololu drivers interfacing with a NEMA 17 and a ball-screw. The screw has a 2mm pitch and a diameter of 16mm.

After reading several of the guides for setting up Marlin and checking running the calculator on the prusaprinters.org page I used a steps/mm value of 1600, under the assumption that the default for the Pololu drivers was 1/16 microstepping.

1600 steps/mm produced very large z movements, so I scaled down, testing and measuring as I went. Eventually, it turned out that 100 steps/mm produces an accurate movement. I press the 1 mm button in CW and see 1 mm of motion. However, the 0.025 mm button now requires 3 clicks to activate and seems to travel further than 0.025mm.

Querying the position with the M114 command shows that each button press is incrementing the position by 0.025mm, but the motor only responds to the third press.

I think I'm misunderstanding something about the firmware, and any help would be much appreciated.

A-ha.

It turns out I didn't have any of the jumpers under the stepper driver board attached. For anyone else running into this issue, here's the table:

jumper Yes/No step size
1 2 3
no no no full step
yes no no half step
no yes no 1/4 step
yes yes no 1/8 step
yes yes yes 1/16 step

Switching to 1/16 microstepping, I find that the 0.025mm button in CW works great.

Good to hear that you fixed your issue, and thanks for posting the info about the jumpers! It's always the details that get you!

(Also welcome to the forum!)

hi dears
i have some problem with my firmware,marlin have lots of variables to change.
i am working with e Generic driver of CW beta 13
i appreciate if any one can help me.