Solving Problems Beyond The Welding Terminals - Boss MIG 165 Operating Manual

7.02

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 GMAW:
a) 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:
l
Gas cylinder contents and flow meter
Ensure that the gas cylinder is not empty and the flow meter is correctly adjusted to 15 liters per
minute (0.5 cubic feet per minute)
l
Gas leaks
Check for gas leaks between the regulator/ cylinder connection and in the gas hose to the power
supply.
l
Internal gas hose in the power supply
Ensure the hose from the solenoid valve to the MIG gun adaptor has not fractured and that it is
connected to the MIG gun adaptor.
l
Welding in a windy environment
Shield the weld area from the wind or increase the gas flow.
l
Welding dirty, oily, painted oxidized or greasy plate.
Clean contaminates off plate.
l
Distance between the MIG gun
Keep the distance between the MIG gun nozzle and the work piece to a minimum. Refer to distance
from the MIG gun nozzle to the work piece in 5.03.
l
Maintain the MIG gun in good work order
Ensure that the gas holes are not blocked and gas is exiting out of the gun nozzle. Refer to the
WARNING.
Do not restrict gas flow by allowing spatter to build up inside the MIG gun nozzle.
Check that the MIG gun O-rings are not damaged.
WARNING: Disengage the drive roll when testing for gas flow by ear.
b) Inconsistent wire feed
Wire feeding problems can be reduced by checking the following points:
l
Wire spool brake is too tight
Feed roller driven by motor in the cabinet will slip.
l
Wire spool brake is too loose
Wire spool can unwind and tangle.
l
Worn or incorrect feed roller size
BOSS Inverter Mig 165¡¢ 200 Operating Manual
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