Linear actuator using ClearPath Integrated Servo System @ 72V DC

Supposing the curve of the M04025 is similar accordingly to the model @Thanos is showing, I found a model at Teknic with similar specs. Two small differences :
3 x the weight and 4 x the price. ;-)

We have also this size.

Don’t know if the st80 or st90 corresponds to the NEMA 34 standard. It doesn’t looks like.

https://m.de.aliexpress.com/item/32845039986.html

A st80 fits on a nema32 gearbox
I am not shure a st90 fits on a nema34 gearbox

Be careful with nema32 there are different shaft sizes

Yea same shit for the nema 34

Yes, but be aware of the different shaft sizes. They may need different coupler link sizes...

But otherwise, these have advantage on size for the power and price of course.

I should watch my language. I wanted to say same issue for the nema 34. Of course different shafts. ;-)))

If you consider this for a rotary geometry, the main issue with this power is the strength of the gearboxes.

If you want to go with a high precision, low backlash planetary gearboxes in this size, you may overcome their max torque.

The strongest items in the industry that I saw are rated with the 1:64 reduction at 120Nm nominal 180Nm peak and 360Nm emergency torque.

If I calculate it properly, you may not expose those with an input torque above 3, 3,5Nm

So basically, the tremendous power of this motor can’t be used at its full potential.

If you want to stay with a nice planetary mechanics, a bigger boxes (like size 115) with conversion flange should be adapted

You can still use 20:1 planetary and have speed and it will hold load fine. And max RPM or torque is adjustable on these servomotors...

Sure sure but it would give you 150 RPM which is more than 4 times to much
I would be a waste in my opinion. ;-)

Another thing is that if you want a good performing Stewart, you have to go with the levers above 150mm. In order to keep a security margin I would advise at least a reduction 40:1.

If you want to fully profit of the potential of this motor, I am afraid bigger planetary or worm boxes are needed.

If you want to fully profit the potential of this motor youre not use a low efficienty wormgearbox

I'm planning to build my linear actuators using a foldback (I think this is what it means) design with a pulley drive to reduce overall length of the actuators and also provide a means of changing the ratio if I don't like the speed.

I was thinking I could 3D print the pulleys, since with a firmware update my heated bed can supposedly get up to around 120c max and my hot end up around 160c max. Not sure what material would be best, but all this talk about gearboxes not being strong enough has me thinking metal pulleys might be required. Do you guys think I could 3D print pulleys that would be strong enough for this? I was planning to use ABS, or maybe Nylon.

A belt needs tension i am not shure the belt will walk fine upon printed pulleys
For a fuw bucks you have metal pulleys there is not much money to win.
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Tell me @Thanos please, can you interface in the same way all the range of these motors ? I mean, there is no problem to go with bigger frames like ST90 ST110 ST130 and ST 150 ?

Hey guys. I'm looking at dimensions and the kind of travels geometrically possible are a bit higher than I expected! I assume that it's inadvisable to use that kind of translational travel, is that correct? What kind of limitations should I expect to put on sway and surge? Not in terms of preventing clipping,, that's a separate thing. I mean in terms of maybe mechanical interference, actuator angles that could cause damage etc.

Answer: the upper joints of the actuators seem to be the primary limiting factor.

The actual range is limited by the geometry of the platform and the max angles the universal joints can provide...

I wasn't looking for exact info, just some idea. Mostly I was wondering if there is an angle we generally don't want the actuators to go beyond regardless of u-joints and collision issues. The closer they get to horizontal the harder they have to work to raise the platform correct? I meant things like that.

Answer: the upper joints of the actuators seem to be the primary limiting factor.

Edit: Removed this post to avoid confusion when people search for info in the future.

Summary: I asked what the side effects would be of lengthening the short sides of the hexes relative to the long side lengths. After FlyPT corrected a value I had wrong I learned that heave was decreased by lengthening the short sides of the bottom hex. I did not experiment with the upper hex dimensions as there was no need.

You might loose in the combination of DOF's.
You also get the actuators more vertical. Might be an advantage in the load of each one, but it's also more unstable. It's like putting all actuators vertical, and with joints, all gaps have a larger effect on the rig.
Might be wrong, I have to think more about it.
But I don't think it's a problem in your measures.
But you are wrong with range. Range is half of the full travel.
So if minimum extension is 1015 and maximum 1580, full travel is 565mm and range is 565/2=282.5