OK Dave - I am sharing.
Still working on ways to improve the finished cut quality of acrylic parts. Having solved the problem with striations on the cut edge my next problem was with reflections from the table or work supports overheating or damaging the finish on the reverse of the work. These reflections were traveling about 50 - 80 mm beyond the work and although they were well out of focus still contained enough energy to cause damage. All metals reflect at 10600nm but glass doesn't so a simple solution was achieved by making a wooden containing box with glass base then filling the box with aluminum, concertina bent, venetian blind slats (on end) as the work support. This really does work so well and the money I have saved over buying ready made honeycomb cutting bed material can all be spent on Beer
(Dave, Sam & Russ would approve of this, I thought).
Tweakie.