Tweco 1000 Cutting Systems - Manual (Page 27)

Manual 0-2710 4-3 OPERATION
quality is desired to avoid a secondary cleaning opera-
tion. Cut quality characteristics are illustrated in the fol-
lowing figure:
Kerf Width
Cut Surface
Bevel Angle
Top Edge
Rounding
Cut Surface
Drag Lines
Dross
Build-Up
Top
Spatter
A-00007
Figure 4-3 Cut Quality Characteristics
A. Cut Surface
The desired or specified condition (smooth or rough)
of the face of the cut.
B. 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.
C. Bevel Angle
The angle between the surface of the cut edge and a
plane perpendicular to the surface of the plate. A per-
fectly 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 work-
piece.
E. Bottom Dross Build-up
Molten material which is not blown out of the cut
area and re-solidifies on the plate. Excessive dross
may require secondary clean-up operations after cut-
ting.
F. Kerf Width
The width of the cut (or the width of material re-
moved 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.
H. Various Materials and Thicknesses
The following table defines the typical cut quality on
various materials and thicknesses: