Ghost/Shadow Lines

Ghosts in the machine.

Ghosts

Earlier I cut a coaster, and it had a massive ugly ghost line on it.

Ghosts

And then I noticed that the air nozzle was loose. So I tightned it and I thought that I had fixed the issue. But even here notice that it is not fixed.

And then I got suspicious. I've been cutting towards the bottom of the table (towards me, because my arms are short), and to the lower right.

That means I am at the maximum length of the laser path. So I cut a coaster near the upper left.

Ghosts

The text is deeper, and the perimeter cut is cleaner. And so the suspicion must be that I have a laser alignment issue.

The intensity varies accross the bed, but the distance of the ghost lines from the intended lines seems unchanged. So...take that for what it is.

Next step: alignment, and then revisit.

Rabbit Laser Machine Hardware Parts, with useful names

Focal Tube Assembly

I adjusted the mirrors. There were some issues and I dealt with them! And then I raised the table so the laser was close to the wood and shut pulses.

Ghost line!

And I captured the ghost! This image should show a dot where I pulsed the laser. And it should not show that arc to the right.

The laser was not coming straight out the hole in the air nozzle. It was not properly centered.

Ghost line!

This is my 'pulse, look, move, repeat' track once I realized what my problem was.

I thought about drilling out the air nozzle, as you need to do when you put in a 100mm focal length lens.

But getting the mirror aligned seemed the better choice.

Now off to try engraving a real object!

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