@uncle_bob
I don't think you have anything to worry about.
Review the Lisa video:
[www.youtube.com]
A negligible load is being applied to the arm via the screw rotating, and the nut moving up and down.
The arm has virtually a stress free ride.
A small bending moment will come from a weight on the end effector.
Do you plan to hang some thing really heavy off the end effector?
I was thinking that you might be mounting some thing like a 1/2" router.
In that case I'm more concerned with dampening the vibrations, and the joints being tight.
Filling the hollow arms with lead shot would be good for vibration dampening.
"Total energy transfer", dead blow hammers are a good example of this.
6061 aluminum, 1.5" x 3" with 1/8" wall tube is going to work fine if all you're using it for is plastic filament fusion welding.
Better than 6061 is 2024 aluminum, some of it's structural properties are similar to the strength of mild steel, but it's pricey.
Don't weld 2024, the copper will migrate and compromise the strength.
If you are going to heat the enclosure, then you might want to consider the amount that the arms will grow.
But you probably can get away with assuming that every thing will expand equally.
Even wood is a good choice for this application. Knot free cedar it's strong, light, and rigid.
The only issue with wood is making sure that the resin doesn't hider glue from bonding too it.
I don't think you have anything to worry about.
Review the Lisa video:
[www.youtube.com]
A negligible load is being applied to the arm via the screw rotating, and the nut moving up and down.
The arm has virtually a stress free ride.
A small bending moment will come from a weight on the end effector.
Do you plan to hang some thing really heavy off the end effector?
I was thinking that you might be mounting some thing like a 1/2" router.
In that case I'm more concerned with dampening the vibrations, and the joints being tight.
Filling the hollow arms with lead shot would be good for vibration dampening.
"Total energy transfer", dead blow hammers are a good example of this.
6061 aluminum, 1.5" x 3" with 1/8" wall tube is going to work fine if all you're using it for is plastic filament fusion welding.
Better than 6061 is 2024 aluminum, some of it's structural properties are similar to the strength of mild steel, but it's pricey.
Don't weld 2024, the copper will migrate and compromise the strength.
If you are going to heat the enclosure, then you might want to consider the amount that the arms will grow.
But you probably can get away with assuming that every thing will expand equally.
Even wood is a good choice for this application. Knot free cedar it's strong, light, and rigid.
The only issue with wood is making sure that the resin doesn't hider glue from bonding too it.