burning tips

By 2008642 (*)

Date 01-15-2009 00:28

I'm having troube with and automated welder. At arc start it frequently burns the wire back to the tip. Its a Miller Axcess 450 and I'm running an .035" 308L wire. Transfer mode is short circuit and I have a tip to work distance of 1/2". The parameters are set to 18 volts and about 355 IPM and a gas flow rate of 40 CFH. The arc start settings are approximately 2 volts higher and the IPM are about 15 IPM lower. It appears that after its done welding the wire is fused on the inside of the tip. You can take a pair of pliers and wiggle the wire and it will free up. Any suggestions would be greatly appreaciated. Thanks. Josh

By Lawrence (*****)

Date 01-15-2009 10:23

Hey Josh

355 ipm is very high for short circuiting transfer... That's a lot of current for 18 volts.

I guess first off, Have you asked Miller about this? High speed tip issues were a problem for Axcess models about 3 years ago... Word on the street was that many of these were solved... So if your power supply is not brand new,,, Miller should be your first place to go for advice..

I'm wondering why your using a $12,000 power supply to make short circiting welds that could be accomplished with a $2,500 dollar unit... Or conversely why not try RMD, which your Axcess was especially designed for, and produces much more controllable pulsed, short circuiting type output.

If the wire is fusing at the tip it is prolly better to look at the ramp up and down parameters in your termination sequence rather than your arc start sequence. So maybe you could tell us a bit more about that.

By 2008642 (*)

Date 01-15-2009 19:23

On the particular line in question we do run some accu pulse. It depends on what part # we are running. The power supply is only about a year old. When you say RMD your talking about regulated metal deposition right? I will look in to that a little more. I will get the exact ramp parameters when I arrive this afternoon and post them. Maybe it will help. Thanks.

By BryonLewis (****)

Date 01-15-2009 21:08

Josh,

Could be liner or feeder problems. I ran an Invision 354? on 304 and 316 SS with 316L .045 wire. I used GMAW-P and not short circuit. I would have similar problems when I used the wrong nozzle. We used a short nozzle where the tip would stick out just past the nozzle mouth for carbon steel and a long nozzle where the tip was recessed about 1/4-3/8 for the SS. If I forgot to change the nozzle when we changed over, it would weld like dog sh**.

Just my 2 cents.