I’m teaching students with this machine and need a decent material for learning, I am thinking plastic. I’m wondering if buying a length of Trex lumber might be good value. I’ll need a lot of these, so just thinking outside the box.
If you have any plastic suppliers in your area reach out to see if they sell drops/scraps. Very often they pay for disposal and they’ll happily sell you a pallet full of cut offs very inexpensively. Generally any plastics cut well, you might consider a single flute cutter and definitely a neutral or an upcut bit. Do not run a downcut bit with plastic or it’ll melt! Delrin would be great to cut but is worth more/costs more so it’s rarer than HDPE/PE/acrylic/polycarb/etc.
I ended up by PVC trim boards and it works great, ultimately it cost 62 cents for a 3x4 inch part.