What is the wall thickness of the tube you are welding?

I have produced 1/4" fillets with Robotics using WFS speeds up to 450 in/min with .045 wire, giving good quality welds.

In your case, we are looking at a straight butt joint weld. How fast can you weld this part ? Hmmm ..Looking for maximum WFS. The maximum WFS that can be used depends several factors. I am also assuming, this is not a pressure vessel.

Since WFS is related to current, an increase in WFS will directly increase welding current. Therefore, as SteveB asks whats is the thickness of your part. Well you indicated Tube and not Pipe; therefore you have a burn through factor directly related too how much Welding Current you can use, therefore a limit on WFS. However, you will need to R&D. Time is money..ok...so you want to use a higher than normal WFS, the highest deposition rate. Rotation Speed will then be increased proportionally to WFS prevent burn through. Now, by increasing your welding speed you will notice than it becomes increasingly difficult to produce the same quality weld at a higher speed, as compared to the weld that was produced at a lower weld speed. The weld starts to look too convex and narrow ? It really all depends on what type of quality you can live with. The quality that you deem acceptable, will sorta determine how fast you can weld.

Supp. R&D Factors that are important to your App.
(1) Wire Size
(2) Gun Welding Position on Tube ( ? Oclock pos)
(3) Type of Shielding Gas (Argon-CO2 Mixture %)
(4) Mill Scale (ON or OFF)
****IMPORTANT - An extremely very important factor in obtaining high welding speeds in automatic set-ups is the cleanliness of the material. Removing mill scale will SIGNIFICANTLY allow you to use higher welding speeds and weld quality will be far superior.

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I would start here:

(1) .035"(.9mm) solid wire
(2) Pos Torch between 1 to 2 Oclock, rotate CCW.
(3) Shielding gas Argon-CO2 mix. (5% to 20% CO2)
** Note: Shielding gas mix will be greatly be affected the material cleanliness (Mill Scale). A more potent Argon mix will not be so forgiving to mill scale; causing undercut.
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This is to all of us posting helpful hints and information.

Not that im looking any type of gratification ! But when you actually go out of your way, on your own time, in replying to a thread ...a simple Thank You ! or hey thanks for your input ill keep you posted on my progress !..it's kind nice to hear or simply just ethical that your weren't just typing for nothing... No ?

Marc

MC PRO-FUSION
(www.mcprofusion.com)

Hey trhogan,experimenting w/rpm of your servo in direct relation to tube dia. in conjunction w/ wfs ie.amprge and vltge ie.arclength has probably enabled you to find a correct setting for your application.From experience,when looking for increased welding speeds,shielding gas selection was key.I am only familier with three different mig applications.Short arc transfer,globular transfer,      spray transfer and pulse.I won't go into all four but the spray transfer has proven to be the best for applications you have described.Material thickness would be helpful,but .035 and .045 wires are pretty versatile and economical for up 3/8 maybe 1/2in. material, for anything heavier I would probably go to an .062 wire for a spray application. With any spray arc application,resulting in 23 volts+ 98%ar2%O2 will be a bare minimum .A local welding supply may recomend something new.Sorry I could not calculate specs.for your application but there are unknown variables which are too numerous to substitute.