Tweco SL100 - Manual (Page 27)

Manual 0-2962 4-3 OPERATION
C. Bevel Angle
The angle between the surface of the cut edge and
a plane perpendicular to the surface of the plate. A
perfectly perpendicular cut would result in a 0° bevel
angle.
D. Top - Edge Rounding
Rounding on the top edge of a cut due to wearing from
the initial contact of the plasma arc on the workpiece.
E. Bottom Dross Buildup
Molten material which is not blown out of the cut area
and resolidifies on the plate. Excessive dross may
require secondary cleanup operations after cutting.
F. Kerf Width
The width of the cut (or the width of material removed
during the cut).
G. Top Spatter (Dross)
Top spatter or dross on the top of the cut caused by
slow travel speed, excess cutting height, or cutting tip
whose orifice has become elongated.
4.06 General Cutting Information
WARNINGS
Disconnect primary power at the source before
disassembling the power supply, torch, or torch
leads.
Frequently review the Important Safety Pre-
cautions at the front of this manual. Be sure
the operator is equipped with proper gloves,
clothing, eye and ear protection. Make sure no
part of the operator’s body comes into contact
with the workpiece while the torch is activated.
CAUTION
Sparks from the cutting process can cause
damage to coated, painted, and other surfaces
such as glass, plastic and metal.
NOTE
Handle torch leads with care and protect them
from damage.
A. Piloting
Piloting is harder on parts life than actual cutting
because the pilot arc is directed from the electrode to
the tip rather than to a workpiece. Whenever possible,
avoid excessive pilot arc time to improve parts life.
B. Torch Standoff
Improper standoff (the distance between the torch tip
and workpiece) can adversely affect tip life as well as
shield cup life. Standoff may also significantly affect
the bevel angle. Reducing standoff will generally result
in a more square cut.
C. Edge Starting
For edge starts, hold the torch perpendicular to the
workpiece with the front of the tip near (not touching)
the edge of the workpiece at the point where the cut
is to start. When starting at the edge of the plate, do
not pause at the edge and force the arc to "reach" for
the edge of the metal. Establish the cutting arc as
quickly as possible.
D. Direction of Cut
In the torches, the plasma gas stream swirls as it
leaves the torch to maintain a smooth column of gas.
This swirl effect results in one side of a cut being more
square than the other. Viewed along the direction of
travel, the right side of the cut is more square than
the left.
Right Side
Cut Angle
Left Side
Cut Angle
A-00512
Side Characteristics Of Cut
To make a square - edged cut along an inside diameter
of a circle, the torch should move counterclockwise
around the circle. To keep the square edge along
an outside diameter cut, the torch should travel in a
clockwise direction.