cnc machine stiffness calculator

[routercnc]

Good afternoon.
Please tell me with the calculations in your table:
Calculating Ixx values for more complex shapes (using parallel axis theorem)

Please give an example.

I’m away from the PC so will give a brief explanation. For complex shapes you need to break it down into a series of standard shapes such as rectangles, calculate the Ixx for each shape, then multiply by the area of each shape and the square of its distance from the overall shape neutral axis and sum these values together.

Google parallel axis theorem for examples. I’ll post a better explanation another time.

[Voicecoil]

You may be able to save a bit of time analyzing the components using this:

https://skyciv.com/free-moment-of-inertia-calculator/

It does shapes such as I beam, T beam and angle as well as tubes.

[routercnc]

You may be able to save a bit of time analyzing the components using this:

https://skyciv.com/free-moment-of-inertia-calculator/

It does shapes such as I beam, T beam and angle as well as tubes.

That's quite a handy calculator, so it might be all you need.


But if you want to know what it is doing, there are quite a few steps involved (which is why you are better making a spreadsheet if you want to do lots of them). I've shown a worked example which uses 2 rectangles in a T shape. You can make any shape using more rectangles but need to include more terms in each equation associated with each new rectangle.

The T shape is worked through in 7 steps:









Hope this helps.