its the machines rigidity is the weak part, the spindle i use is a 2.2 kw spindle which is plenty for aluminum. I was cutting a 2.5" thick chunk at my job with 2.2kw spindle yesterday and I had no problems. this photo is roughing with a 6mm bit 1.25" deep before flipping it over and doing the other side.
the round tubes resonate way more than any traditional square shaped gantry style machines i have operated. think of the onefinity tubes like wind chimes.
These machines are capable of a great finish if you change the motors but in a commercial enviroment they would be to slow… too many passes needed at a much slower speed than every other machine i have ever used. I have only use commercial machines so i am not comparing it to hobby machines which i admit might be unfair.
i cannot suggest these frame for real metal work.
I actually just did a major overhaul on the electronics and wire on my elite foreman…
info can be found here… Replacing STEPPERS for DMM-TECH AC Servos