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Current setting:
The correct current, or amperage setting primarily
depends on the diameter and type of electrode selected. The side of
the electrode box usually indicates operating ranges. Select an
amperage based on the material thickness, welding position (about
15 percent less heat for overhead work compared to a flat weld) and
observation of the finished weld.
Length of arc:
The correct arc length varies with each electrode and
application. As a good starting point, arc length should not exceed
the diameter of the metal portion of the electrode. Excessively long
arcs (too much voltage) produce spatter, low deposition rates,
undercuts and sometimes porosity.
Angle of travel:
Hold the rod perpendicular to the joint and tilt the
top of the electrode in the direction of travel approximately 5 to
15°. For welding vertical up, use a forehand technique and tilt the
top of the rod 15° away from the direction of travel.
Speed of travel
: The proper travel speed produces a weld bead with
the desired contour (or crown), width and appearance. Adjust travel
speed so that the arc stays within the leading one-third of the weld
pool. Slow travel speeds produce a wide, convex bead with shallow
penetration. Excessively high travel speeds also decrease
penetration, create a narrow and/or highly crowned bead, and
possibly undercuts.
Manipulation:
Each welder manipulates or weaves the electrode in a
unique style. Develop your own style by observing others,
practicing and creating a method that produces good results for
you. Note that on material 1/4 inch and thinner, weaving the rod
typically creates a bead that is wider than necessary. In many
instances, plain, straight-ahead travel works fine. To create a wider
bead on thicker material, manipulate the electrode from side to side
creating a continuous series of partially overlapping circles, or in a
PARAMETERS
MMA WELDING MACHINES
Summary of Contents for IBL M200-77
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