Hey everybody!
I have an application where I require some wire feeders close to the robot tool, yet due to their weight, they cannot be integrated into the tool itself. So, my question is: is it possible to attache the feeders on a zero gravity arm, then attach the end of the arm to the robot? As much as I can say, the balancer should just add some inertia to the robot, however I've never seen anything similar, so maybe I am overlooking something... Any opinions?
"zero gravity" arm/ tool balancer
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WolfSpirit -
October 10, 2015 at 2:07 PM -
Thread is marked as Resolved.
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Well, how close do they need to be? You haven't specified your requirements or limits very well.
You could, for example, mount the feeder to the robot wrist. Most dress packages include a "tennis bracket" that fits snugly around the A6 flange, without actually being bolted on (it's a friction fit), with a bar sticking out to one side (the "handle" of the "tennis bracket").
Or, you could add a mounting bracket to the adapter plate beween the A6 flange and the tool, and mount the wire feeder to that.
Of course, this will increase the robot's payload and inertial loads, so you'll have to see what side effects that has on your path speed. You'll definitely need to re-run your Load Determination in order to get accurate $LOAD_DATA values.
If the wire feeder can be further away, there are mounting points atop A3 that are usually used for dress pack items that don't fit on the wrist assembly.
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Well, maximum distance should be 1m, but the main ideea is that, given the weight the tool already has, mounting it on the robot is not really possible, that is why I was considering using the tool balancer, that would support the weight of the feeders, while the robot would still do the handling. The robot will just do soldering oher a plane surface, so I would say its path would allow the balancer being attached to it, but, as I said, never seen anything like this before, so I might be missing some aspect of it...
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What model robot is this? What payload rating? It sounds like it's one of the really small models.
So... it's not just CG/inertia issues you're trying to avoid -- you're trying to avoid putting the weight of the wire feeder onto the robot at all, if I'm understanding you correctly. Hm....
A tool balancer might work. It'll really depend on the robot's travel. And how the feeder connects to the robot tool -- if it's just a wire hanging in mid-air from a reel, you're going to have issues when the robot moves up, since the tool balancer won't make the reel pull back the slack in the wire. OTOH, if it's an *active* wire feeder, and you have a sleeve or cable keeping the feeder at the right distance from the robot tool, then the balancer would probably work. You'd want a tool balance with just a little more lift than the weight of the wire feeder, though. And since the wire feeder's weight will change as it's wire payload is consumed...
You'll also possibly need a 1-D or 2-D travel axis for the balancer, above the robot, to keep the balance above the robot at all times, rather than letting it build up lots of diagonal tension. Again, this all depends on the exact details of your layout.