Laser not toggling on and off fast enough-leaves shadows and overburn

[parsec (FerAS)]

Try disabling Bi-directional fill:

But likely you have slope in your laser, run the job on this post and reply with pictures of the output:

Burn Offset LighutBurn 1.7.03

Given one picture and four words, I think @JimNM has nailed it. This test pattern helps identify mechanical problems: GrundTest.lbrn2 Scale it to fit 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. Upload good photos of the result so we can look over your shoulder.

In case you need to adjust something:

Guide to mechanical adjustments and maintenance

Mechanical Issues - LightBurn Documentation

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After check if your machine needs the scanning offset adjusted:

Scanning Offset Adjustment - LightBurn Documentation