Not a newbie, but I have a new problem; Splatter when engraving two ply plastic

[ednisley]

@LaserFocusCustomEngraving

caught this on a scope

Thusly:

Where Those Random Dots in Engravings Come From

It seems everybody engraving acrylic with a CO₂ laser has seen random speckles appearing in places where the design shows a blank. Regardless of the suggested remedy in the many threads on this topic, nothing stops the dots. It turns out the problem lies inside the high-voltage laser power supply, which occasionally fires the tube at random, even though the controller has disabled the supply’s output. Although I’ve measured only two power supplies, other folks report random dots regardless of t…

The discussions in that thread are informative.