Newbie here.
I am working on a logo in Lightburn. I am burning fill on Birchwood (for testing) at 3600/70 using a Longer Ray5 10watt. It seems to look okay in the software.
However, on the board I am seeing what appears to be blurred (or doubled offset?) lettering.
Suggestions? Thanks!
Most likely it’s something loose in the X axis drive train, with a screw in the motor pulley being the prime suspect and belt tension coming in second.
This test pattern is useful to identify mechanical problems:
GrundTest.lbrn2
Scale it uniformly to fill the platform and run it as fast as it will go in Line mode with optimizations turned off and power set to mark a sheet of cardboard. Any differences from the design will be informative; a photo will let us look over your shoulder.
The Preview window shows actual laser head motions, rather than the overall design, so it’s a better indication of what you should see on the material.
Get in the habit of previewing everything before committing to a burn on spendy material and save yourself considerable heartache & confusion. 
Just me but I have found anything over 3000mm/min doesn’t have any effect.
This would depend on the machine and material. I see a big difference between 3000mm/m and 6000mm/m, requiring a power change to compensate.
I haven’t been lasering for a while so maybe it was 6000 that it seemed to max out.
Okay, definitely better than before. I tightened the nut on the laser head assembly, and gave the belt on that same rail a touch more tightening. 
I do see that the places where the letters intersect has some lighter burning. I’d like to even that out if I could. On that fill layer (“DBE”) I toggled on “Flood Fill” on the Advanced tab. Anything else or better I should do? Thanks!
You found most of the backlash, but there’s more to do. Testing on paper, rather than wood, will let you concentrate on the actual problem, which will improve the results on everything.
There are no settings compensating for mechanical problems, so fiddling with them can waste plenty of time & material.
I might try enabling scanning offet in device settings if everyting is tight, it may help with jagged lines.
Also I would do an intervel test in laser tools tab.
I purchased some 65 lb card stock from Michael’s Crafts and ran a material test on the paper. Then I used the setting that produced the best results without any burn-through. Seemed to be 10% at 600mm.
Actually, I found while those settings worked well for the larger letters, I had to up the smaller text to 15% power for best results. So, larger at 10%, smaller at !5%. If I used 15% for all, I got burn-through of the larger letters.
This seems to be good results. Though I am now thinking I need to change fonts, as the lettering seems too delicate for engraving on leather, which is what I want to do primarily.
If you note my first post on 10/27, it shows an image from LightBurn. In Lightburn the letters seem to be more robust/bold, and I do not see any separations in them on the bottom like I am seeing on the card stock.
Thoughts? Any suggestions for best fonts for Logos? Thx
The machine still has significant backlash in the X axis, as shown by the “doubled” edges:
You must fix that before proceeding, because it will never get better on its own.
It looks like 'Fill shapes individually` is set. If so, then the Y axis has mechanical problems, too.
As a rule of thumb, when the Preview shows the intended shape, but that’s not what appears on the material, the machine has a mechanical problem.
This test pattern is useful to identify such things:
Scale it uniformly to fill the platform and run it as fast as it will go in Line mode with optimizations turned off and power set to mark a sheet of cardboard. Any differences from the design will be informative; a photo will let us look over your shoulder.
A delicate font that looks great on paper may not work on leather. After you get the mechanical problems sorted out, then trawl through the infinite number of fonts out there for one that both looks good and produces the results you want on the material you’re using.
I’m the type of guy who deliberately used Comic Sans in a presentation: I’m a Bad Example™ of font selection.
Ran the backlash test pattern. On the 2nd run (right image) I turned on the “Hide backlash” option. That seems to provide a noticeable improvement.
I really don’t know what else you would do to try to remove backlash. Suggestions would be much appreciated.
Backlash happens when this thing moves and that thing doesn’t follow along as it should at a place where those two things meet.
Look at every place where two things join: motor to coupler, coupler to shaft, shaft to pulley, belt to gantry, this to that. Make sure every joint is secure, which may require taking stuff apart and putting it back together while paying attention, because you cannot assume the folks on the factory assembly line got it right.
Once you get all that settled, you can look for things that flex when pushed, but you’re not there yet.
The Hide Backlash “optimization” doesn’t really solve anything, it just pushes the problem somewhere else where maybe you won’t notice it:
You get to decide when you’re done, but …
This is for Sculpfun lasers, but ought to give you an idea of things to investigate and what to do:
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