Re: CO2 Laser Bodor
I think it is going to be less about the nozzle and more about the focal length of the lens. If you have the standard 2" lens in your machine, a 4" lens might do a better job with the relatively thick foam due to the longer profile of the 4" beam's profile. Yes, you may need a new tube+lens+nozzle assembly.
Often it is better to make multiple passes for each cut at a lower power versus trying to cut with just one pass at higher power.
Consider cutting multiple layers of foam and then gluing them together versus cutting one really thick pieced of foam.
The quality of the foam is important. Cheap stuff does not laser well and it falls apart/"sheds" after a short time.
"80 Watt” 700mm x 500mm Ke Hui 7050 Laser (Similar to the Red Sail)