Thank you for the tests and the feedback @mgomes !
That would confirm my assumption that the higher engraving speed of 1000mm/s make the effect more visible.
The Laser On TC can be negative!
A Laser On TC of -1000us means: the laser fires, waits for 1000us, then starts moving the galvo mirrors.
The effect is barely visible, but you can see the burn-in at the start of the line:
As with the other timing values, you are looking for a value where the lines meet at a nice right angle. - For the Laser On TC, look at the beginning of the fill-lines. - For the Laser Off TC, look at the end of them.
Here is a testcard I ran on a 20W Galvo with a “RAYCUS” Fiber Type:
There is a burn-in at the beginning already at -250us. - No need to go lower than this.
My goal is in the positive range. I’d say around +150us:
Take a look at this page for a good explanation of the Galvo timings
I hope, this helps and does not overcomplicate things!