It loves to burn so watch out.
Laser cutting hdpe sheet.
Consider masking tape but unless it sticks to the plastic really well then pull it all off again as loose tape encourages fire.
Hdpe is similar to candle wax.
Molten plastic on the surface each side of the cut can be a problem particularly if the air assist blows it around.
Wavelength the 10 6 micron wavelength is absorbed well by nearly all plastics and is the best choice for most plastic laser cutting engraving and marking.
Polycarbonate is a poor choice for laser cutting.
As a result the part that you cut especially for thin sheets may come out of the laser cutter slightly warped.
This is the frequency of light t he laser cutter uses to cut materials so it is very ineffective at cutting polycarbonate.
Place one pair of self locking c grips at each location that the side of the plastic sheet intersects the edge of the worktable to hold the plastic sheet in place while you cut the sheet.
Platform size must be large enough to hold the largest pieces of plastic that will be laser processed or be equipped with class 4 capability for processing larger pieces.
Lay the marked sheet of hdpe plastic flat on the worktable and slide the plastic sheet so the marked cut line rests 1 2 inch beyond the edge of the worktable.
The window of the laser cutter is made of polycarbonate because polycarbonate strongly absorbs infrared radiation.
Polycarbonate is often found as flat sheet material.
I actually use hdpe cutting boards and cut with normal woodworking tools.