Morning All - I have made a model using iso 100mm thick Al for the base and walls. It gets 14/16/60N/um. I think a lot of the deflection is in the Z axis not the walls. So I am going to leave the walls and base and move to the gantry. I can get 6" thick 6061-T6 which cleans up to 100mm thick nicely. So that's going to be the basic building block. I'm moving my router at the moment and it has reinforced the idea of parts being less then 50kg. The base is about 200kg and I'm having trouble finding 3 guys to help lift it into my truck... So the rules are use 100mm max al plate or thinner, parts <50kg make it as stiff as possible. The 20N/um target maybe too high for such a machine. Target envelope 400x400x400m or 350x350x350mm.

ISO13 walls weigh 43kg each and the base is two pieces weighing 45kg each. I can make the webbing a bit thicker and still be under 50kg... I'll also have to speak to the machinist about the depth of cut and tool diameters. Say 80mm deep and a dia20mm tool gives me a part rad of 10mm in the ISOgrid that sounds OK... but thats a 4:1 ratio tool maybe a bit long.. back to my day job - Peter