Reply To: 20 or 16 Tooth Pulleys for international version

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The IE edition refers to the tubing diameter and has nothing to do with the pulley teeth count. The only difference is the pulley diameter, the belt teeth pitch is still 2mm. So a 20mm pulley will give you 25% more linear movement per rotation than the 16mm pulley but 25% less torque. I am using 20mm ones but don’t think it really matters that much. I think that the machine rigidity will swamp out the theoretical linear resolution, (just guessing not measured).

You do need to make sure that the firmware you compile and download has the correct number of teeth represented in the configuration.h file. The #define DEFAULT_AXIS_STEPS_PER_UNIT will depend on your pulley teeth, belt pitch, stepper microsteps/step, and stepper steps/rotation.

Something like:
(mm/tooth)(tooth/rotation)(rotation/steps)(steps/microsteps) = mm/microstep

I get (1/160)(mm/microstep) for my 32 microstep/step 20 tooth setup. That is 0.00625 mm/microstep. Do you think that is enough resolution?

For example my configuration.h file has this line:
//SLC for 20teeth/mm puley, 2mm G2 belt, 200 step/rot, 32 microsteps/step
#define DEFAULT_AXIS_STEPS_PER_UNIT {160,160,4535.44,760*1.1}

The first number is for X, and second for Y. The third number is for the Z-axis and is for my imperial threaded rod. You will change that if you use an 8mm rod. The fourth is only used if you make it into a 3D printer with an extruder.

BTW – I would go with 32microsteps if your driver supports it. I think the steppers run smoother and sound better.