Fusion360 FEA group night?


#1

I’m teaching myself how to use Fusion360’s Simulation suite to study static and momentary loads on my printed designs. It would be great to compare notes and learn from you. Who’s in, and when’s good for you?


#2

I like ELMER & COMSOL, FreeCAD can do some basic FEA.
Let’s take a simple beam on two supports with a midpoint loading example and compare.


#3

Or take a real life actuator or arm, something that you have fabricated, that would be even better.


#4

I had planned to bring in real examples I’m working on, partly to get some suggestions about how to improve them. I like the beam idea and comparing different programs.


#5

Hi Dan (@iMakeRobots),

I think I have seen some pancake shaped stepper motors that have the entire stator and rotor accessible so the torque is distributed over a wider area than just a thin shaft; believe the motors were from an old VCR. Hard drives have servo motors that also have a “wide” moving surface.
This way there is no “concentrated” loading of the plastic at the bolt or key interfaces and getting shredded.

Use epoxy (or even velcro, velcro might “yield” some) to attach the moving arm surface to such motors.

Good luck,
RK


#6

Try re-running your simulation with a simple cylinder instead of the threaded fastener. I re-ran some numbers and a simpler simulation with your latest design seemed to at least be in the ballpark.


#7

with a simple cylinder?


#8

In other words, you want to rule out the possibility you are getting weird results due to interaction with the threads. See if the best case scenario of a perfectly matched cylinder/rod to hole works, and then go from there.


#9

And you may be able to find shoulder screws in an appropriate size. E.g. https://www.mcmaster.com/#90265a126/=1afdm7x


#10

The safety factor with M3s was 0.54.
The safety factor with M5s is 1.57. Much better! Aiming for >=3.0. Great
idea, @JDMc!