Hi All - I increased the Z Axis plate thickness from 6mm to 8mm and reran the numbers. The deflection dropped from 0.47mm to 0.26mm which is worthwhile. See attached. I'll review the corrugated design properly next design round. Round 1 is too determine the main structural features of the machine and that the machine has the DNA or skeleton so to speak to achieve the desired performance.
Since there is a lot of talk about vibration in the forum I ran the eigenvalue solver and determined the first three vibration modes. Would like to put up videos but it's a hassle editing them and converting them to fit here so here's some stills. The first mode is the gantry lozenging evenly all along itself. I intend to put some shear webs in so this will solve that vib. The next vib is a combined lozenge and twist, again the webs will push these up the scale. The model so far is stainless steel so if I did the parts in aluminium the deflection would be 3x the figures quoted. So far its the Z Axis plate that is the main contributor to deflection and since I'm going to make it a bit longer I need to make it stiffer!! I've looked around at a few routers here and 25mm aluminium plate is a common size for such a part. So I've done some comparison calcs against this plate. The 207mm wide SS corrugated plate is the same rigidity as a 25mm thick aluminium plate so I'm happy with that. It's also 76% the weight of the 25mm thick Al plate so I'm very happy with that. So the 8mm will be even stiffer and lighter but less margin. This is worthwhile to reduce the stack of the system so far. I'd like to stay with 6mm plate so maybe I can bend it deeper to make it stiffer. This points at using 20mm bearings so I have more depth to play with. Better get the X Axis going then can back to these decisions.
I'm also thinking about a metal bench vs the timber bench. Pros and cons....Peter