Author Topic: Kuka robot for painting  (Read 200 times)

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Offline iljalways

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Kuka robot for painting
« on: October 11, 2018, 06:00:04 PM »
Hi, we are looking at getting KRC2 GM robot for wet and powder coat painting, I was told by my manager that it needs to have air driven servos to prevent static / spark for safety, I never heard of it, I was trying to find some info on the KUKA website & Manuals, but I could not find any info in that relations.
Just wondering does anyone have any info on it?
are there even air servos?
is there anything special about a painting robot?
or can I use a regular material handling robot and adapt our paint gun to it?

Thanks.


Offline panic mode

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Re: Kuka robot for painting
« Reply #1 on: October 11, 2018, 06:39:27 PM »
all Kuka robots use electric motors.
painting applications are hazardous due to mist/fumes (explosive atmosphere), which could be ignited by a spark.
lookup specs for painting robots...

1) http://www.robot-forum.com/robotforum/kuka-robot-forum/read-first/
2) if you want reply about robot, post it in forum
3) read 1 and 2

Offline iljalways

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Re: Kuka robot for painting
« Reply #2 on: October 11, 2018, 06:46:16 PM »
Thanks Panic mode for the info, I had never seen anything but electric motors on kuka, but I thought I double check, I will do more research on kuka painting robots.

have a good day.

Offline panic mode

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Re: Kuka robot for painting
« Reply #3 on: October 11, 2018, 07:46:43 PM »
painting is not something Kuka is after... there is tons of other cheaper robots that are used in this application.
1) http://www.robot-forum.com/robotforum/kuka-robot-forum/read-first/
2) if you want reply about robot, post it in forum
3) read 1 and 2

Offline SkyeFire

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Re: Kuka robot for painting
« Reply #4 on: October 13, 2018, 11:40:15 PM »
Don't think I've ever seen an "air servo" robot for painting applications, although I'm willing to bet something like that exists, somewhere.

Most "explosion proof" robots I've seen used in paint have normal electrical servo motors, but include a pneumatic positive-pressure system inside the robot arm.  As long as the air pressure inside the arm is higher than the ambient atmospheric pressure, this will (in a robot made for that kind of thing) prevent any dangerous fumes from getting into the motors, internal wiring, etc.  Not sure I've ever seen a KUKA built this way, though.

Beyond keeping a positive pressure inside the robot itself, there's probably special requirements for all the connectors.

Fanuc has always seemed to be the "big dog" in the robotic paint market.  I've seen some "explosion proof" Kawasakis, years ago, for similar environments.

Offline Spirit532

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Re: Kuka robot for painting
« Reply #5 on: October 14, 2018, 04:51:05 AM »
Not sure I've ever seen a KUKA built this way, though.

Many smaller Kuka bots(enclosed) have somewhat of an equivalent system - purge gas.
It's not exactly what you'd consider explosion proof(as it's primarily made for moisture), but if you push nitrogen or something similar through it(membrane separator, no need for tanks), it's good enough to be safe around paint.
My KR3(CRS F3 rebadge) has purge input next to the tool air line, as do some Denso bots. I'm not sure if it's an option on the Agilus ones, but they're mostly hermetically sealed regardless(especially the CR and WP versions). Some silicone grease stuffed into the connectors(internal included!) and it should be compliant.

I should note though, that it's never positive pressure(at least in robots). There's always a flow somewhere. If there was a positive pressure anywhere within the robot, you could start counting hours until all the grease makes a swift exit through the gearboxes and onto the floor.

Offline SkyeFire

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Re: Kuka robot for painting
« Reply #6 on: October 16, 2018, 02:26:06 PM »
Not a high pressure, but there has to be some positive pressure, relative to ambient, or else there's no point (and no flow).  Cranking the internal positive pressure up to 10bar would be pointless, and (as you pointed out) probably drive the grease out of the bearings in short order.  But unless the pressure inside the robot was a least a few millibar above ambient, explosive vapors could infiltrate through simple convection.  There would need to be enough positive pressure to ensure that any airflow between the interior of the robot and the outer environment was always outwards.