First design - Few questions

[9designs]

Hi Jazzcnc, thanks for the feedback.... I hadn't done much calculations of the side supports, so I've now gone back and tried to calculate some forces and deflections. The absolute values are perhaps hard to quantify but the level of improvement is at least relative.

Initial layout I applied a 500N lateral load to one side, ignoring the opposite side for sake of easy calculations. Load just applied to the top fixing hole of the Section8.
The analysis show stress concentrations as such.





Adding some ribs and thickening the bottom plate that holds the carriages, also added the Section 8 to better simulate the load area.



Stress plot looks much better etc.




I hadn't correctly put the weight of the spindle and stepper motors in, so even with the extra material thickness I'm at 66Kg. Hopefully keeps with one X axis ballscrew.

The base, though not detailed is intended to be anchored to a side wall of my garage that it will stand next to. So it won't go for a walk and will further supported. That said I can always beef it up after testing etc.

For spindle is this the sort of item recommended?
http://www.cnc4you.co.uk/Spindle/Spi...VFD-plus-Mount
Is it worth it for a DIY machine?
If so I'll need to look at the Z axis anyway so will have another go at that. I was wanting to keep the offset from the Y axis down. Many designs seem to have a large distance, increasing the moment and forces from the cutter. I was looking reduce the offset.
I'll have another think.... and revisit the layout.

What sort of DOC is normal from Gantry type machines? Tying to get a feel for the forces to expect.

I can see the costs running away a bit on this project