Ramps 1.4

Mostly Printed CNC - MPCNC Advice
1

I’m nearing the end of my hardware build and I’m about the tackle the electronics.

I have an old working ramps 1.4 with A4988 drivers here that never got used in a project but while I wait for the mini rambo I would like to use it to troubleshoot any issues with the mechanical aspects. I read that the firmware provided is set up for another driver, the DRV8855 , and the A4988 only have half the steps to work with. So the question is related to the firmware, what to I change to get the steps right with the A4988 ?

I saw this line :

#define DEFAULT_AXIS_STEPS_PER_UNIT { 200, 200, 800, 200 } //MPCNC

Do I half these numbers for the A4988 like so ? :

#define DEFAULT_AXIS_STEPS_PER_UNIT { 100, 100, 400, 100 } //MPCNC

 

Thanks!

2

That should work. The z-axis number is based on a leadscrew instead of a threaded rod. The last number is for the extruder if you’re going to use the MPCNC as a 3D printer.

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3

Yup, that worked, thanks for confirming!