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03-25-2009, 08:12 PM #1
Anyone know anything about spot welders on robots ?
What I want to know is, are the spot welders used on robot arms typically self contained as far as the power supply requirements or do they typically have seperate power units ?
I've got one on the end of a 2000 year Nachi robot which seems to be self contained...one cable connects to the robot control box for communication with the control apparently, and another huge cable (3 wires, one of which is ground) that connects to what bascially seems to be just a large on/off breaker and huge circuit breaker.
There are at least 4 hoses coming off the spot welder...not sure if they are for air or water or both... my guess is that it may use air to close the spot welding electrodes and maybe the water is for cooling ??
03-25-2009, 08:28 PM #2
Two hoses will be for coolant, the other two are probably hydraulic. I've not seen any that are pneumatic, although they probably exist. They need large clamping forces usually and are either servo (newer systems) or hydraulic.
All of the units I've seen have a separate control unit, usually mounted on the side of and integral to, the robot control cabinet. It *could* be self-contained though.
Probably no clear answers without some pysical investigation though.
03-26-2009, 12:37 AM #3
Further investigation reveals this is a Savair TMP series, which seems to have a large air cylinder for closing.
03-26-2009, 01:00 AM #4
Is Savair now part of ARO?
anyway, robot units usually have the transformer integral with the welding gun.
The lines are for air cylinder & water cooling, spot welding transformers are usually water cooled due to the large currents involved. The trans formers are usually driven with 480VAC.
anything look similar here:
the cable from the weld gun is usually connected to a controller of some sort, which will fire a mechanical contactor or SCR / ignitron unit.
Entron is a good place to start if there's no weld control.
03-26-2009, 06:29 AM #5
Sometimes the actual welding tip is water/liquid cooled.
Memories are vague,but I worked on the machining side of a place where we build pieces of the cars assm line,they were of the welding nature,longest 1 that i recall was 300 ft.
I do recall machining copper alot,with plenty of waterlines installed.
I found it abit scarey,mixing water and electricity.
I will stop rambling now.
03-26-2009, 10:57 AM #6
Savair was originally famous for air cylinders, hence the name "sav air"...as in efficient use of air.
Engineering at ARO Welding is emailing me the drawings on this gun and it is indeed pnematic... 970 lbs of force at 70 PSI.
Next to figure out is if it needs a seperate controller like the Entron that Chris refers to, or is the gun control integral to one of the boards already in the robot box, programmed at the same teach pendant the robot motion uses.
(on edit) Breaking news.. according to Nachi tech, the robot control also controls the spot welder...no seperate control needed.
07-08-2009, 07:54 AM #7
Recently had a chance to buy a brand new ARO spot weld gun for cheap but afraid to buy it due to it being servo controlled rather than air close/open. My impression is servo would be superior but I suspect I would be forced to also buy an ARO servo controller to actually operate the darn thing. (which would probably cost a small fortune)
Any thoughts on a potential DIY controller for a servo robot gun ?
Keeping in mind I have the weld power suppy and weld control already and would just need to concoct a method of activating the close/open motor (but also keeping in mind it may be more complex than just "close/open" command... as there may be a need to control the torque of the close, speed of the close/open, and timing of the close cycle ! )
07-08-2009, 10:43 AM #8
What type and size servo?
07-08-2009, 11:02 AM #9