Home made stand for a KR6

Started by Xylotica, September 14, 2015, 09:49:47 PM

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Xylotica

I am designing a stand for my KR6-arc, and I'd like some advice from anyone who has done that already.
Maybe a kind of twisted prism like on the attached image, if I can't get my hands on a large pipe segment.
I would like to run a FEM analysis on this part, but I don't know what kinds of forces and torques it will be subjected to.
Any ideas about that ?

Cheers,

Johannes @ Robots in Architecture

Hello,

Here are the relevant values for the KR6-2, which should be very similar to your KR6 arc. That should make simulation and dimensioning easier!
Fv = Vertical force Fvmax = 4,600 N
Fh = Horizontal force Fhmax = 5,000 N
Mk = Tilting moment Mkmax = 5,200 Nm
Mr = Turning moment about axis 1 Mrmax = 4,200 Nm

Best,
Johannes

Xylotica

#2
Hello Johannes,

and thanks for your answer.
Any idea how I should combine those efforts to create load cases ?
In construction, for example, you would have to perform analysis with :
1.5*SNOW
1.5*WIND
1*SNOW+0.7*WIND
etc...

Factors above 1 are security coefficients which are not relevant if the given values are already "Extreme" values.
But it is important to know what combinations of forces and moments are likely to occur simultaneously because they can yield unfavorable cases.
For example, 0.5*Fh+0.5*Mk can be worse than 1*Fh.

Cheers,

Johannes @ Robots in Architecture

Phew, not really my area of expertise, but I'm sure that the KUKA values already contain all kind of safety coefficients.
After all, they assume a maximum force of 4600N for a 200kg machine.

Best,
Johannes

Xylotica

Hmmm... Load values, but no certified, normed, approved and stamped  load combinations ?
How un-German... :)

Anyways, thanks for the data, I'll try to mix it somehow.



Johannes @ Robots in Architecture

For a final confirmation it may be a good idea to call the KUKA hotline. However, chances are good that they will also only quote the manual ;)

Xylotica

I applied all the loads simultaneously on my FEM model.
Stress in not a concern, and max displacements are less than 0.2mm

That should be fine...

Height of the stand is 700mm ; weight : 67 kg.

Cheers,

Xylotica

Oh well,

I found a piece of ΓΈ405x6 pipe rusting in the scrapyard, and I thought it would be even better than my fancy bent sheet metal, so I went back to the drawing board...
Laser parts are ordered ; can't wait to get this thing done and start the serious stuff.

Xylotica

There 'ya go.