Laser Banding

[Dale Rajchel]

I was etching a photo on marble. I started to get zebra type lines on my photo. I thought I had a bad image. I then tried other images that worked in the past. I even tried to etch some large block letters. Same problem. After talking to tech support from my supplier, they said it's called banding. They said three reasons cause this:
1) not having a direct dedicated electrical supply.
2) loose or worn bearings on the carriage
3) out of focus

After checking the bearings, I found that one of them wasn't touching the carriage and the other was loose. I tightened up the loose bearing and the problem went away.

Today I'm ordering new bearings.

I spent hours trying to figue this out. Hope this helps someone inthe future.

[Dan Hintz]

They said three reasons cause this:
1) not having a direct dedicated electrical supply.
2) loose or worn bearings on the carriage
3) out of focus
1) This is rare in areas where the electrical grid provides pretty clean power... this is most of the US. Rodney (Gold) had issues stemming from poor grid power that were resolved with a good power conditioner, but I hear the power grid in many areas of Africa aren't very clean.
2) Likely cause in most cases.
3) I don't see that ever being the cause.

Other possible causes... improper image resizing, incorrect dithering algorithm, improper color palette, loose lens/mirror, and there's one more on the tip of my tongue, but I'm doing three things at once so it escapes me.

[Joe Kace]

When I experienced banding, it turned out to be a bad tube. I called Epilog and they sent me out a new tube right away ( warranty ) and the problem went away.