4" Lens and crosslinked PE Foam

Just curious. It seems a 4" FL creates a more straight beam. Who has cut crosslinked PE Foam with such setup and how thick of a material could be cut with reasonable result?

From the look of this guys work you can get a pretty deep cut

I’ve cut 3/8" thick PE foam from McMaster-Carr with a 2-in lens with no trouble at all. Haven’t tried anything thicker, though. This was with a 60-watt laser.

Thanks for your info.
I dropped them a line and asked my questions. It will be interesting whether they will answer and release some info.I saw some of the deep cases they produce. But they also might use awaterjet for these thick blocks. So far I experimented with 25mm material which cuts reasonably well on my standard 80W red&black…