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# Mini Gerbil fine tuning

All mini Gerbils are defaulted to conservative feed rates and acceleration profiles to ease the installation and give people the a quick up and running solution.

However once you have set it up you can tweak the settings to get the performance out of it that you need (raster at 350-400 mm/s). This requires to increase the settings per axis slowly up till you hear and see issues like squeaks and skips. Don't do both axis at the same time. The X axis on the K40 is capable of higher speeds than the Y axis. The acceleration settings are more critical then the feed rates.  Usually scale down the acceleration when you cannot get better performance and see skips.

Slightly adjust the belts for maximum performance and re-test until you find the best settings.

My K40 settings so far -

$110=24000 (X axis feed rate in mm/min)$111=8000 (X axis acceleration)

$120=12000 (Y axis feed rate)$121=5000 (Y axis acceleration)

Cheers, Paul awesome.tech

You can fine tune the current to the stepper motor via the install pot on the two stepper drivers.

The standard K40 stepper motor reference voltage is 0.34 Volt on the adjustment pot. Pololu has a great page about the A4988 current setting. https://www.pololu.com/product/1182

0.34V equates to an I MAX of 625mA (VREF=8IMAXRCS where RCS is 0.068 Ohm).

You can measure this by using voltage meter and measure between ground and the pot turn screw. See attached photo for the measuring points.