cnc machine stiffness calculator

[routercnc]

:tup: thanks Ross and ecat.

Torsion - I don't know how to calculate the twisting (torsion) constant K for arbitrary shapes so it is work in progress. There's probably a parallel axis theorem equivalent. But all the regular shapes are done.
[EDIT: Bit of research and it's not possible to calculate the torsion constant for arbitrary shapes since they are not symmetrical and will warp, leading to large errors. Only option is to use FEA (Finite Element Analysis) software. Alternatively choose a regular shape which is closest to your arbitrary shape, and use Engineering judgement over whether your arbitrary shape is likely to be better or worse than this for torsion. Sections with more material distributed around the outside are the best for torsion e.g. sections approaching a tube.


The other work in progress is the router mounting plate tab - lots to do here. At the moment all the Z axis is assumed rigid, including the cutting tool.

The more I add to this sheet, the more I realise how much is missing, but hopefully it's a start.

Ross, I think you can still contribute. You were working on a Z axis weights sheet - that could be useful to tab at the front of this one because at the moment the Z axis weight (or mass!) is a user estimate.