Tweco PakMaster 75XL Plus - Manual (Page 30)

SECTION 4: OPERATION 24 Manual 0-2746
4.06 Cut Quality
Cut quality requirements differ depending on applica-
tion. For instance, nitride build-up and bevel angle may
be major factors when the surface will be welded after
cutting. Dross-free cutting is important when finish cut
quality is desired to avoid a secondary cleaning opera-
tion.
The following cut quality characteristics are illustrated
in Figure 4-9 below:
Cut Surface
The condition (smooth or rough) of the face of the cut.
Bevel Angle
The angle between the surface of the cut edge and a plane
perpendicular to the surface of the plate. A perfectly per-
pendicular 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.
Dross Build-up and Top Spatter
Dross is molten material which is not blown out of the
cut area and re-solidifies on the plate. Top spatter is dross
which accumulates on the top surface of the workpiece.
Excessive dross may require secondary clean-up opera-
tions after cutting.
Kerf Width
The width of material removed during the cut.
Nitride Build-up
Nitride deposits which may remain on the surface of the
cut when nitrogen is present in the plasma gas stream.
Nitride buildups may create difficulties if the material is
welded after the cutting process.
Kerf Width
Cut Surface
Bevel Angle
Top Edge
Rounding
Cut Surface
Drag Lines
Dross
Build-Up
Top
Spatter
A-00007
Figure 4-9 Cut Quality Characteristics
Cut quality will vary on different types of and material
thicknesses.
The following table shows the cut quality that can be ex-
pected from this equipment for materials with a thick-
ness from gauge to 3/4 inch (19.1mm):
T yp e o f M a t e r ia l
G a s
C a r b o n
S t ee l
S t ain les s
S t ee l
A lu m in u m
A i r
G o o d -
E x c e l l e n t
G o o d -
E x c e l l e n t
G o o d -
E x c e l l e n t
N i tr o g e n G o o d G o o d G o o d
Description of Cut Characteristics
Excellent - Minimum bevel (0 - 4°), minimum kerf (2 x
tip orifice diameter), little or no dross, smooth
cut surface.
Good - Slight bevel (0 - 10°), slightly wider kerf (2-1/2 x
tip orifice diameter), some dross (easily re-
moved), medium-smooth cut surface, slight top
edge rounding.
Fair - Excessive bevel (over 10°), wide kerf (over 2-1/2 x
tip orifice diameter), medium to heavy dross, rough
cut surface, top edge rounding.
NOTES
Cut quality depends heavily on set-up and param-
eters such as torch standoff, alignment with the
workpiece, cutting speed, gas pressures, and op-
erator ability.