Miller Electric Bobcat 250 Owner's Manual page 65

14-16. Troubleshooting − Incomplete Fusion
Possible Causes
Insufficient heat input.
Improper welding technique.
Workpiece dirty.
14-17. Troubleshooting − Lack Of Penetration
Lack of Penetration
Possible Causes
Improper joint preparation.
Improper weld technique.
Insufficient heat input.
14-18. Troubleshooting − Excessive Penetration
Excessive Penetration
Possible Causes
Excessive heat input.
Incomplete Fusion − failure of weld metal to fuse completely with
base metal or a preceeding weld bead.
Increase amperage. Select larger electrode and increase amperage.
Place stringer bead in proper location(s) at joint during welding.
Adjust work angle or widen groove to access bottom during welding.
Momentarily hold arc on groove side walls when using weaving technique.
Keep arc on leading edge of weld puddle.
Remove all grease, oil, moisture, rust, paint, coatings, slag, and dirt from work surface before
welding.
Lack Of Penetration − shallow fusion between weld metal and
base metal.
Good Penetration
Material too thick. Joint preparation and design must provide access to bottom of groove.
Keep arc on leading edge of weld puddle.
Increase amperage. Select larger electrode and increase amperage.
Reduce travel speed.
Excessive Penetration − weld metal melting through base metal
and hanging underneath weld.
Good Penetration
Select lower amperage. Use smaller electrode.
Increase and/or maintain steady travel speed.
Corrective Actions
Corrective Actions
Corrective Actions
OM-4419 Page 61