Weird dots all over my engraving

[bernd.dk (Bernd)]

Acrylic engraving leaving little dots

Hi, I have had our omtech 50w engraver for about a month and we have started to try acrylic engraving. Unfortunately no matter what speed/ power we use we seem to get little dots around the engraving, picture attached. Material: Cast Acrylic (also does it on non cast) Speed: 600 Power: 20 DPI:300 Material has a small layer of dawn soap before engraving

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