Tweco 300 MST Arcmaster - Manual (Page 45)

39
WARNING 9
Disengage the drive roll when testing for gas flow by ear.
9.01.02 Inconsistent Wire Feed
Checking the following points can reduce wire-feeding problems:
1. Wire spool brake is too tight. Feed roller driven by motor in the cabinet will
slip.
2. Wire spool brake is too loose. Wire spool can unwind and tangle.
3. Worn or incorrect feed roller size. Use 'U' groove drive feed roller matched to the
aluminum wire size you are welding.
Use 'V' groove drive feed roller matched to the
steel wire size you are welding.
Use ‘knurled V’ groove drive feed roller matched
to the flux cored wire size you are welding.
4. Misalignment of inlet/outlet guides. Wire will rub against the misaligned guides and
reduces wire feedability.
5. Liner blocked with wire debris. Wire debris is produced by the wire passing
through the feed roller, if excessive pressure is
applied to the pressure roller adjuster.
Wire debris can also be produced by the wire
passing through an incorrect feed roller groove
shape or size.
Wire debris is fed into the liner where it
accumulates thus reducing wire feedability.
6. Incorrect or worn contact tip. The contact tip transfers the weld current to the
electrode wire. If the hole in the contact tip is to
large then arcing may occur inside the contact tip
resulting in the electrode wire jamming in the
contact tip.
When using soft electrode wire such as
aluminium it may become jammed in the contact
tip due to expansion of the wire when heated. A
contact tip designed for soft electrode wires
should be used.
7. Poor work lead contact to work piece. If the work lead has a poor electrical contact to
the work piece then the connection point will
heat up and result in a reduction of power at the
arc.
8. Bent liner. This will cause friction between the wire and the
liner thus reducing wire feedability.