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)
$121=5000 (Y axis acceleration)
You can fine tune the current to the stepper motor via the install pot on the two stepper drivers.
The standard K40 stepper motor reference voltage is 0.34 Volt on the adjustment pot. Pololu has a great page about the A4988 current setting. https://www.pololu.com/product/1182
0.34V equates to an I MAX of 625mA (VREF=8⋅IMAX⋅RCS where RCS is 0.068 Ohm).
You can measure this by using voltage meter and measure between ground and the pot turn screw. See attached photo for the measuring points.
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I will be responding to a few posts with newer updates to questions that seem to not have responses. I am in the group that has the no ribbon laser and did end up getting everything installed and working (for the most part).
I am very entry level to all of this and don't seem to understand half of what I'm reading. My question here is where do I actually go to make these adjustments? My laser fires but not quite how I want yet. I'll keep looking for settings to mess with but any help would be appreciated!
Hi, we wrote a few blogs about the engraving adjustments and settings which seems to be hidden away. Having a ribbon or non-ribbon version does not matter for the settings or the engraving qualities.
In a nutshell there are just two configuration '$ settings' to adjust: $28 for the frequency (0-60Hz, 1-120Hz, 2-250Hz,3-500Hz,4-1kHz 5-default 1.5kHz) and $30- laser power range default is 1500. The other laser power range setting in Lightburn or Laserweb you need to match with $30 (e.g. use the same value). The $30 setting is related to the age of the tube. Older tubes are less powerful and you need to lower the range a bit to get a darker image output. The frequency 250-1500Hz seems to work the best and the faster you go, the higher you need to set the frequency.
This leaves you to play with speed and resolution to tune. The engraving material and laser focus is another factor which determines the quality of the engraving.
The blogs are here:
https://awesometech1.wpengine.com/k40-laser-best-possible-engravings/
https://awesometech1.wpengine.com/gerbil-engraving-calibration-guide/
https://awesometech1.wpengine.com/k40-engraving-calibration-instructions/ (older blog)
https://awesometech1.wpengine.com/what-are-settings/
enjoy!