Status on yellow robot arms?

Science
#41

Unless you’re machining with a needle at 50k RPM it’s not going to do any machining.

Let’s say you load up a 1/2" endmill in the HAAS 3/4 tons of side load.

Assuming the spindle and collets etc are weightless, with our 1.6kg of side load force we’d need to have an endmill diameter of 0.024" to get the same force per rotational speed (chip load).

Maybe we get a dentist’s drill for it? Pneumatics should save on weight and give us closer to the RPMs we’d need.

Edit: crummy napkin math:
(0.75+907.2)/(pi*(0.25)^2) = (1.6)/(pi*(x)^2)
solve for x, x=0.012 as a radius
0.024 as a diameter, so less than a 1/32" and more than 1/64"

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#42

If you take a .001 tooth load at .1 depth of cut in aluminum the load is only about 10 lbs

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#43

I figured I’d chime in on this (I know I’m a little late to the game). It’s a little late but I have used Staubli robots in the past (however with their newer CS8 controller). I can’t remember how we left this but I remember that we had a lot of difficulties getting the controller to work. Now I do know that it wouldn’t be that hard to build a new controller for it since those servos are so low power. Did we ever get the controller to boot up and work with the robot?

#44

Yes, but the general consensus was that it was not worth using. The controller is older than me, and iirc required programming in some archaic late 90’s language.
I’d really like to get the damn things running, or at least be given full reigns on one of them, because it really wouldnt take much. Even odrives at this point would probably work.

#45

Yeah agreed. The CS7 controllers aren’t worth saving unless you could salvage the motor drives and talk to them directly. But it seems like less work to just use an off the shelf controller and drive setup.

#46

There is going to be discussion on the arm this weekend at the Machine Shop meeting. The Machine Shop Committee is probably its last saving grace. If there is not going to be enough serious interest in it, it will probably not be here much longer.

#47

I don’t see a reason to build our own STMBL drives. They handle around the same amount of power as an odrive, which is also open source, but we can also actually BUY an odrive instead of taking a nine month long “we’re getting around to it” and “hopefully making it work” journey. I just don’t see a cost vs time benefit for something this trivial.
It would really suck if the space got rid of them, but if they do I’ll want to be on the list of people to buy it.

#48

I agree. [EDIT] I looked into those controllers and my biggest concern is that they are designed for different type of motors. The joints on these industrial robots are much more complex and higher voltage. Like typically 380v three phase. Might be cheapest to just pickup a used CS8 controller. I’ll do some research. I have contacts at Staubli in South Carolina that might have an idea.

#50

What time is this meeting? I’ll try and make it.

#51

Looks like Saturday at 5:00 PM

https://calendar.dallasmakerspace.org/events/view/15808

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#52

You beat me to it by a few seconds. Yep 5pm

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#53

Will the meeting be virtual as well? I’d like to attend to discuss the arms but I’m not sure if i can make it in person on Saturday

#54

Yes it will.

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#55

Wasnt able to make it but I’m sure y’all will figure out what the best course of action is.

#56

Paraphrasing – despite the interest in the arms providing 5 axis ability, Machine Shop decided that they couldn’t support enough weight to be useful, especially considering the number of volunteer hours that they’d eat up to make them really usable. So – back to Science for their consideration.

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#57

Sounds good.

#58

Now that’s how you really get your moneys worth from a 200k machine and software

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#59

Reminds me of a Henry Kutner story, “The Proud Robot”. It was in a collection along with “Mimsy”–good stuff.

#60

Maybe large scale 3D fab is an option.

#61

Or we could 3d print a bridge out of steel:

OK maybe this is beyond our capabilities lol…

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