Engraving problems

[Jose Valladares]

Hello ,
I have a engraving Chinese machine, it was working very good , but some days ago it start doing some lines in the engraving(see picture attached).I check the mirrors alignment and it seems ok. I was wondering if it is only matter to focus the lens in a different position or if there is another problem related to it.
I'll appreciate any suggestion
thanks

[Joe Hillmann]

What is the material you were engraving on? It kind of looks like the grain of the wood is showing through.

[Dan Hintz]

Looks like you have pockmarks at the edge of those lines, too... I'd say check for loose mount on your mirrors/lens, then make sure the drive belt and associated cogs are snug.

[George M. Perzel]

As Dan said, check for a loose mirror or lens-and make sure your head is perpendicular to the work surface. It can get out of line do to a number of factors.
Best Regards,
George
Laserarts