I am getting my acrylic sheet ordered and wondering which would be the best way to have the edges polished.

They offer diamond, flame and buff polishing. I am also thinking of getting 10 or 12mm thick as well to get stiffness.
Display is to be FTIR method, though I might have a go at LLP if its proves not to be too expensive and continues to get good reviews.

I would go with the flame polishing method, its the easiest and fastest to do and provides ( if done right ) and exellent crystal clear edge. Diamond finishing usually leaves very fine tool marks that needs to be scraped clean then buffed anyway . To do any of the 3 methods requires scrapping of the edge before final finishing so you may as well get the cheapest done.

I myself wouldn’t worry at all about the polishing of the edges and such for FTIR, I think that is a myth helped into the world by Jeff Han in his paper?
In fact we had better results with rough/raw/unpolished edges opposed to polished edges.
It is a lot of hassle to polish and sand the edges and from our point of view the result is actually worse.
Of course it is up to yourself what you decide.

It is a lot of hassle to polish and sand the edges and from our point of view the result is actually worse.

I think this is because if you polish the the light will go straight through, but if they are foggy and unpolished it scatters the light in a more random pattern, which is what FTIR needs to function.

Now I am confused.
To polish or not to polish that is the question. I wont be doing it myself anyway, it will be bought polished, just more expence if I do ecide to get it.

The edge to be beveled? Does this actually make any real difference in refacting the light and improving blobs.
Also does extruded or cast make a difference to the light, no figures are given for this in the spec sheets so is their any reall difference other than that cast costs more. I willl probablee go for cast as they dont have 10mm extruded.

Like I mentioned earlier, don’t polish it.
Beveled edges gave us better results (clearer blobs).

Saturating the Plexiglass with IR I would think to be more important than the little that may escape through the edges. I highly doubt that the results of unpolished or unbuffed edges of plexiglass can be better than polished. I would really like to see some sort of experiment on that.

I also imagine that this has something to do with the IR LEDs themselves, the angle etc.  I wonder if there’s some kind of surface that could scatter the IR light a bit that could be run around the edge of the highly polished acrylic.  Looking forward to testing.