[laserdes]

I installed a replacement tube in my 40 watt laser engraver last week. It seems to perform well when cutting and I'm back to using speed and power settings comparable to what worked with my old tube when it was relatively new.

There is a problem with engraving though. Compared to my prior tube in its earlier days a lot more power is required and the final appearance is irregular with obvious banding. I'm using the the same image preparation technique and settings that gave me good results with the old tube.

Could improper alignment be the cause of the problem?

[Tweakie]

I would suggest that you check the alignment. The procedure is quite simple but it can take some time to get it spot-on.

Tweakie.

[Tweakie]

One extra thought.
If you are unlucky enough to have a machine where the mirrors are bolted together then it may be good to take some time to radius the ends of the adjusting screws and fit small compression springs (see pic).
It makes alignment and adjustment soooo much easier.

Tweakie.