Tweco 52 CutMaster - Manual (Page 34)

CUTMASTER 52
OPERATION Manual 0-4961 4T-2
Kerf Width
Cut Surface
Bevel Angle
Top Edge
Rounding
Cut Surface
Drag Lines
Dross
Build-Up
Top
Spatter
A-00007
Cut Quality Characteristics
Cut Surface
The desired or specified condition (smooth or rough)
of the face of the cut.
Nitride Build - Up
Nitride deposits can be left on the surface of the cut
when nitrogen is present in the plasma gas stream.
These buildups may create difficulties if the material
is to be welded after the cutting process.
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.
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.
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.
Kerf Width
The width of the cut (or the width of material re-
moved during the cut).
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.
4T.03 General Cutting Information
!
WARNING
Disconnect primary power at the source be-
fore 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.
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.
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.
Edge Starting
For edge starts, hold the torch perpendicular to the
workpiece with the front of the tip near (not touch-
ing) 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.
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 be-
ing more square than the other. Viewed along the
direction of travel, the right side of the cut is more
square than the left.