Wiggly mig wire

[Welderpaul]

Maybe one for @TechnicAl ?

Can wire have a twist in it during the manufacturing process? I've noticed that every 5 mins or so, the wire 'jumps' around as it exits the tip, and does a little circle before going back to normal. New liner, new tip (of the right size), torch lead straight and nothing wrong with the wire feed as far as I can see it. It leaves a visible little wiggle in the bead where it has happened. I've known it happen before but only when the tip has worn in an oval shape.

Odd.

 

[TechnicAl]

Yep it certainly can

Its called cast and helix

unwind a full circle and lay it on the floor. It should lay relatively flat. If it lifts at one or both ends more than 5mm (maybe 10mm) there is too much helix.

The cast is the diameter of one "natural" circle........it should be about 1000mm...........less than 600mm is too tight more than 1500 and it wants to jump off the spool.

easier to show than describe

This is partly why wire in drums works better on robots.......robots cannot correct the "unwind"

clear as mud?

 

[Welderpaul]

Thanks Al, that makes sense.

When I pull the 5m or so out of the torch when changing a spool I noticed that it tries to wind itself back up to a circle maybe 200mm diameter and is like a spring. Might be because I am pulling it out of the torch with a bit of force and deforming the wire?
I'll try a bit tomorrow.

 

[Robotstar5]

This is partly why wire in drums works better on robots.......robots cannot correct the "unwind"

I've seen robot welders with helix tips fitted as there wasn't enough cast in the wire to ensure good contact, also seen the effects of too much cast "keyholing" the contact tip!.

 

[TechnicAl]

Thanks Al, that makes sense.

When I pull the 5m or so out of the torch when changing a spool I noticed that it tries to wind itself back up to a circle maybe 200mm diameter and is like a spring. Might be because I am pulling it out of the torch with a bit of force and deforming the wire?
I'll try a bit tomorrow.

Look at the wire on the spool. Running it through the torch can deform it. If its OK going in then its the drive rolls etc that are set wrong.....misaligned, too much tension etc etc.