Cutting HDPE and acrylic are very different things.
I had to cut HDPE in the past and did not have time to find the good cutting parameters and the result was not good.
Better be careful and perform some tests before doing the job. Perform the test on the exact same material. HDPE 1000 cuts very differently than HDPE 500. If fact I made tests on a sample that was supposed to be 1000 and was probably 500 and did not had time to do them again on 1000.
Don't expect to hold the material with double sided tapes. You can't glue HDPE, except with specific processes.
And you won't be able to sand it and I doubt you can polish it. Your cut has to be perfect. HDPE 1000 is difficult to cut and I had vibration issues (mainly due to parts holding). Steve is perfectly right.
I may be wrong and it can be easy to cut with the right parameters, but I never had to cut HDPE again and had no occasion to improve the cut.
W7 - Aspire 8.517