My experience in cutting both plexiglass and HDPE is that you can expect the edges to be a bit rough, even if using a good carbide blade.
The blade will cut (and by the way - as it cuts, it will throw a constant stream of hard bits of plastic in your face. Safety glasses are essential!). But the friction of the blade rubbing against the plastic causes it to also melt, at least on edge of the cut. So its not unusual to see the edge that the blade moves away from left a bit rough.
The rough bits can easily be removed with a gloved hand (you can do it bare handed but it hurts - DAMHIKT), coarse sandpaper or a file.
Not know much about you being this is your second post here, we do not know what tools you have available or your experience. but that blade you are using is a steel blade used for cutting plywood such as paneling not regular plywood. It can be used but will dull very quickly because of the glue in plywood. plywood also has grains running both directions and that too will dull it quickly. That is why they make different blades for ripping with the grain and crosscut when cutting cross grain. You can cut plastics with it but again thin plexiglass, not the HDPE you are cutting. Now if you are cutting hardwoods or even pine you will start burning the wood in the cut. Too many teeth left in the cut and that causes heat. That is why it is a thin material blade. Can you cut with it, sure you did. But you are dulling that blade quickly.