Tweco Fabricator 141i Operating Manual - Manual (Page 67)

Fabricator 141i
Manual 0-5145 4-7 BASIC WELDING GUIDE
4.02 MIG (GMAW/FCAW) Welding Troubleshooting
Solving Problems Beyond the Welding Terminals
The general approach to fix Gas Metal Arc Welding (GMAW) problems is to start at the wire spool then work through
to the MIG Gun. There are two main areas where problems occur with MIG, Porosity and Inconsistent wire feed
Solving Problems Beyond the Welding Terminals - Porosity
When there is a gas problem the result is usually porosity within the weld metal. Porosity always stems from some
contaminant within the molten weld pool which is in the process of escaping during solidification of the molten
metal. Contaminants range from no gas around the welding arc to dirt on the work piece surface. Porosity can
be reduced by checking the following points.
FAULT CAUSE
1 Limited or no shielding gas flows
out of the MIG Gun nozzle.
Check that the MIG Gun connection is fully engaged into the MIG
Gun Adapter. The o-rings in the MIG Gun connection must seal
the shielding gas within the MIG Gun Adapter so the shielding gas
flows into the MIG Gun and out thru the MIG Gun nozzle.
2 No shielding gas flow. Ensure that the shielding gas cylinder is not empty and the flow
meter is correctly adjusted to workshop welding: 15-25 CFH or
outdoors welding: 35-46 CFH.
3 Gas leaks. Check for gas leaks between the regulator/cylinder connection and
in the gas hose to the Power Source.
4 Welding in a windy environment. Shield the weld area from the wind or increase the gas flow.
5 Welding dirty, oily, painted,
oxidized or greasy plate.
Clean contaminates off the work piece.
6 Distance between the MIG Gun
nozzle and the work piece.
Keep the distance between the MIG Gun nozzle and the work piece
to a minimum. Refer to section 4.01
7 Maintain the MIG Gun in good
working order.
A Ensure that the gas holes are not blocked and gas is exiting out of
the MIG Gun nozzle.
B Do not restrict gas flow by allowing spatter to build up inside the
MIG Gun nozzle.
C Check that the MIG Gun O-rings are not damaged.
Table 4-2: Solving Problems beyond the Welding Terminals-Porosity
!
WARNING
Disengage the feed roll when testing for gas flow by ear.