First Post ! Question(s) about KRESS spindle mount

[Xylotica]

Hi folks !

This is my first post here, and I'm excited to get in contact with the members of this community.
I have an architecture + engineering background, specifically in steel and wood structures and tensile membranes.
My robot is called Wall-E ; it's a KUKA KR6-Arc, and I have yet to fire it up.

I recently bought a KRESS 1050 FME-1 spindle with a mount from Damen CNC, and now I need to design the vertical plate that attaches to the robot's flange mount.
This is what the tool looks like from the KUKA|prc library :


And this is the Damen CNC mount plus the vertical plate that I have designed:


I was wondering why I should raise that vertical plate so high above the robot wrist.
Is it to protect the spindle ?
Is it to eventually attach another tool that would require this ?

Also, why place the tool so low ?
Is it to give a bigger clearance when milling in recessed areas ?

As I'm a complete newbie, any advice on this topic would be greatly appreciated.

Cheers,

[Johannes @ Robots in Architecture]

Hello,

Definitely make the aluminum plate shorter if you only use it for the Kress spindle, there's no advantage in having a longer aluminum plate and I would rather scratch the robot with a plastic part then a sharp aluminum edge ;)
That being said, we never had any serious problems with the plate, so it somehow worked.
What do you mean by "so low"? If you refer to the distance between the flange and the tooltip you've got two factors that act against each other: The closer the distance is, the more it is likely that the robot's A5 collides with the ground when you do five-axis milling - the further away it is, the less stable the setup becomes. So you just have to find some compromise between those two.

I quickly threw together a definition where you can dynamically adjust the length of the plate and test it in PRC - that should make it easier to decide!
Note: Only works with the most recent member version of PRC!

Best,
Johannes

[Xylotica]

Thanks Johannes,

Definitely helpful answer !

Making multiple sets of holes in my vertical plate could allow adjustment of  the flange / tooltip distance I guess...

I noticed that there are 5 taped holes and a non-taped one in the robot's flange.
I suppose that this is a way to avoid fitting a tool upside-down.
But should I add a cylindrical boss on my vertical plate to increase the shear resistance, or should I just ignore it and put 5 screws ?
What do the smart guys do ?

Cheers,

[Johannes @ Robots in Architecture]

Hello,

Sorry for the late reply, I somehow missed your reply!
And yes, there are the index holes, but quite frankly I never use them with smaller robots. I guess they are good to have if you need to mount a tool accurately, i.e. not having to calibrate it on the robot again. However, seeing as the Kress spindle doesn't even have a  (e.g. HSK) tool holder, you have to manually calibrate it anyway.

Anyway, I don't believer that you have to worry about anything with a 6kg payload robot!

All the best,
Johannes

[Sailor Soane]

Did you both use 40mm for the interference fit opening on the aluminum plate?

[Johannes @ Robots in Architecture]

Hello,
I'm not completely sure what you are referring to - the circular spindle holder? You can buy that ready-made, we got it from there: http://www.sorotec.de/shop/CNC-Mechanik/Fraesmotoraufnahmen/43er-Eurohalsaufnahme-.html
Best,
Johannes

[Sailor Soane]

Ah! I see. Thanks.