There are two kind of acrylic production process: Casting and Rolling.
Casting: Laser engraving mainly use casting acrylic. The engraving place will be white color. This white have a big difference with original transparent.
Rolling: After engraving still transparent, didn’t have a comparison.
When you buy it, you should ask for high purity. Otherwise it will be melt in engraving or cutting.
Generally engraving at back side for looks modeling. So you should mirror your file. High speed and low laser power. If use higher laser power will cause out of flatness at the underside. If need deep engrave, you can engrave more times.
If you need painting at the engraving place, you should deep engraving first, then fire polish it. After paint. Otherwise it looks will be out of uniformity.
Acrylic is easy to be cut. Be sure the operator stand by. Maybe acrylic will be fire.
After engraving, use acrylic paint clean it. Other cleanser will damage acrylic.