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Lines on engraving and engraving quality issues.

I am having a few growing pains as I get going with my new rig:
LB latest version 0.9.02
Older HP laptop Win 10.
Mini Gerbil set as “Gerbil-STM” (recognized controller automatically).

Overall everything is swell. USB hangs conflicting with a wireless mouse on USB but I will sort that out.
Right now I can Line/Fill pretty well and I am just getting going with grayscale engraving.
My initial testing is going well but as you can see I am having a problem with lining for lack of a better word.
All settings are default from setting up the Mini Gerbil with a couple of power range and speed changes.
I have tried several combinations of $30 range settings from 30 to 2000 and settled on 255 as opposed to the 1000 which seems to be the default.
Speed is kind of slow at 20 mm/sec but seems smooth enough. Power is not sorted yet either at around 3 %.

I am kind of all over the map shooting in the dark so any foundational guidance y’all can offer would be greatly appreciated and please treat me like a complete moron as assuming I may be missing the basics.

Also, I almost certainly have not provided enough info so please ask me what else I should include to help debug this.


Uploaded files:
  • Little-house.jpg
  • Grayscale-Lined.jpg

Hi Robert,

Have you looked at the gray scale line interval and the DPI resolution?


Uploaded files:
  • LBgrayscaleDPI.PNG
Cheers, Paul awesome.tech

Yup. I was currently using .1 and .85 but will try .o42/600 as I see in your pic and 3000.

I see 3 passes. Is that a recommendation?

I read that anything under 300dpi was just overlap.

Any thought to the notion it could be grounding issues or not enough current to the Y axis?


Hi Robert, your comments actually triggered my memory. In one case we had a defect step stick which caused the stepper motor to skip steps. Please can swap the step sticks around and see if it goes away or getting in the other axis now. Also you might try to increase the current pot meter on the stepstick (just slightly) to see if that helps.

Cheers, Paul awesome.tech

Thx Paul.

Where would I put my multimeter probes to measure the step stick output that would be changed by rotating the pot?

Also, when I swapped the sticks I got an error 9.

Unable to burn at all.

Any thoughts on that?


Hi Robert, swapping out the step sticks causes issues? That indicates that there is a problem with one of the step sticks. So you probably need to replace the defect one. You can source these from eBay (A4988) or PM me or Dan if you have trouble.

Regarding the ref voltage: you can measure that between the potentio meter (the screw turning metal part) and ground. Ground is the first pin on the right when looking at the step stick as depicted in the pololu picture (potmeter facing you).

See https://www.pololu.com/product/1182

Uploaded files:
  • A4988.PNG
Cheers, Paul awesome.tech

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