The 100 watt (red/black style) Chinese OmTech laser was working fine until ghost lines started to appear while cutting and sometimes during engraving. I checked mirror alignment and all 3 are centered properly. They are all clean as is the laser tube output. Today I installed a new focus lens (1.5") and although the lines are a bit sharper I'm still getting ghost lines. Please see picture.
Can anyone advise me as to what may be causing these phantom lines? Thank you!