Different result depending on pattern left/right or up/down

Hi there,

first i want to introduce myself. My nickname is Tami, i am mid 50 and new to laser engraving. However i have already over 5 years experience in 3d printing. I am still in the 30 day trial regarding Lightburn and also have like no experience with my engraving machine (AtomStack X7 W40) it is brand new. However my first results in wood are very good and i am impressed by laser engraving.

Now i need some help to understand if i do something wrong, if there is an issue with Lightburn, an issue with my Laser engraving machine or if it is just related to material at all.
I try to engrave some coated aluminium business cards, but i get different results. For me it looks like the laser outputs different power depending on if it is moving in X direction or Y direction. To review i have created some pictures i like to share

Infill pattern in X direction:

preview:
engraving-left-right-pattern
result:
engraving-left_right-result

Infill pattern in Y direction:

preview:
engraving-up_down-pattern

result:

for both i use the exact same speed and power settings, i just modify the infill direction.
Why i get this different results ?

Thanks for any help.

I’m guessing this is caused by the shape of the focus dot. I’m guessing that the actual focus dot of your laser is asymmetric so it looks more like a bar than a dot. In your case I assume the bar is taller than wide.

You can confirm this by focusing the dot on dark material and looking very closely or by using a microscope. You could also engrave onto anodized aluminum and it will leave a very sharp line. Do a vertical test and a horizontal test and it will reveal the thickness of the line in that direction.

2 Likes

That does make a lot sense. Thank you so much for pointing this out. I will do some testing and report back to confirm.

regards,
Tami

It is exactly as you have described it. I can not post a good picture as the result is to tiny with just small lines to get a good picture without a decent magnification. But i did create a example picture

Result:
X-Y-directiontest-result

I learned my first lesson, thanks :slight_smile:

regards,
Tami

and now the ultimate question … is there a setting in Lightburn to compensate it ? :slight_smile:

Nice investigative work.

There is nothing in LB that can compensate for asymmetric dot size. The closest thing is something called dot width correction available for images. It is meant to take into consideration that the burned dot shape is not the size of a single point for a given DPI. This prevents overburn. However, it makes no accommodation for dot shape.

I tend to use diagonal lines to get an “averaged” size when it matters for the work I do.

Ok. Thank you :+1:

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