Preface: A Loose Optic (Mirror, lens) can present itself as excessive mechanical backlash and/or scanning offset value issue. This article will address the symptom and possible causes.
Client was in the middle of engraving a water bottle on a rotary an noticed the double image effect as shown in the image below:
The client then disabled their scanning offsets and bi-directional was set to off for the fill layer. The project was then sent from Lightburn again and re-engraved on the same tumbler. The results improved, as shown in the image below:
While it looks like a scanning offset value issue, it was actually mechanical. The Focus Lens was not secure in the Laser Head. So, as the head traveled left and right to engrave, the Focus lens would shift in the head, shifting the beam and mimicking a large mechanical backlash or offset issue.
Nova Series
Retaining Ring for Mirror Three Laser Head Tube Receiver Bolts
For checking the bearings on your Nova series machine, please check out this guide.Odin\Bolt Series
Retaining Bolts for Mirror 3Laser Head Rear Mounting Bolts (Also check the Lens Plate Knobs on the front) (Note that you must carefully remove the laser head from the gantry bar by unloading the spring loaded lower bearings to access the mounting bolts)
The bearings on your Bolt an Odin series machine are spring loaded and do not have an adjustable tension setting.