Tweco 190 MIG Thermal Arc Fabricator - Manual (Page 52)

FABRICATOR 190 WELDING MACHINE
MANUAL GMAW WELDING 5-4 Manual No. 0-4838
2. Inconsistent wire feed
Wire feeding problems can be reduced by checking the
following points:
1. Wire spool brake is too tight.
a. Feed roller driven by motor in the cabinet will
slip.
2. Wire spool brake is too loose.
a. Wire spool can unwind and tangle.
3. Worn or incorrect feed roll size.
a. Use ‘U’ groove feed roll matched to the
aluminum wire size you are welding. Use ‘V’
groove feed roll matched to the steel wire size
you are welding. Use ‘knurled V’ groove feed
roll matched to the flux cored wire size you are
welding.
4. Misalignment of inlet/outlet guides.
a. Wire will rub against the misaligned guides and
reduces wire feedability.
5. Liner blocked with swarf.
a. Slag is produced by the wire passing through
the feed roll, if excessive pressure is applied to
the pressure adjustement device. Slag can also
be produced by the wire passing through an
incorrect feed roll groove shape or size. Slag
is fed into the conduit where it accumulates
thus reducing wire feedability.
6. Incorrect or worn contact tip.
a. 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 aluminum 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.
a. 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 conduit.
a. This will cause friction between the wire and
the conduit thus reducing wire feedability.