Tweco 350 4R Wirefeeder - Manual (Page 48)

7-4 Manual 0-5182
weldskill 250, 350 service
Service
CAUTION
Disengage the drive roll when testing for shielding gas flow by ear.
7.06 Solving Problems Beyond the Welding Terminals – Inconsistent Wire Feed
Wire feeding problems can be reduced by checking the following points.
FAULT CAUSE
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 A
B
C
Use ‘U’ groove drive feed roller matched to the aluminium wire
size you are welding.
Use ‘V’ groove drive feed roller matched to the hard wire size
you are welding.
Use ‘knurled V’ groove drive feed roller matched to the flux
cored wire size you are welding.
4 Mis-alignment of inlet/outlet
guides
Wire will rub against the mis-aligned guides and reduces wire
feedability.
5 Liner blocked with swarf A
B
C
Increased amounts of swarf are produced by the wire passing
through the feed roller when excessive pressure is applied to
the pressure roller adjuster.
Swarf can also be produced by the wire passing through an
incorrect feed roller groove shape or size.
Swarf is fed into the conduit liner where it accumulates thus
reducing wire feedability.
6 Incorrect or worn contact tip A
B
The contact tip transfers the weld current to the electrode
wire. If the hole in the contact tip is too large then arcing may
occur inside the contact tip resulting in the wire jamming in the
contact tip.
When using soft 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 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