Gantry design and FEA analysis

[Voicecoil]

Setup 2 is much more realistic since you want to design for decent performance when the cutter is hanging down a fair way below the gantry, 'coz that's where it will often be used. Having an equal horizontal force on each beam really isn't going to happen as that would mean the workpiece being considerably higher than the bottom of the gantry. 1000N cutting force is maybe a bit much unless you're using big cutters, I've heard figures of 200N tops bandied about before for typical machines such as people on this forum build though I haven't seen the sums behind that. I did find this reference a little while back though:

https://www.ctemag.com/news/articles...e-when-milling

Putting some numbers into the formula for a 1.5mm DOC on a 3 flute cutter at 0.1mm feed per tooth I get a tangential force around 90N for the best 6000 series ali.

It would also be interesting to do an analysis with a plate fixed on the back of your 2 bits of box section as that will make kind of a super box with the Z plate.

PS looking at your pics again, there might be a decimal point adrift in the text for the second set of results.....