Tweco 40mm Cutmaster - Manual (Page 34)

CUTMASTER 40mm
OPERATION 4T-2 Manual 0-5084
4T.02 Cut Quality
NOTES
Cut quality depends heavily on setup and param-
eters such as torch standoff, alignment with the
workpiece, cutting speed, gas pressures, and
operator ability.
Cut quality requirements differ depending on
application. For instance, nitride build - up and
bevel angle may be major factors when the sur-
face will be welded after cutting. Dross - free cut-
ting is important when finish cut quality is desired
to avoid a secondary cleaning operation. The
following cut quality characteristics are illustrated
in the following figure:
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
removed 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 cut-
ting tip whose orifice has become elongated.
4T.03 General Cutting Information
!
WARNING
Disconnect primary power at the source before
disassembling the power supply, torch, or torch
leads.
Frequently review the Important Safety Precautions
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 dam-
age 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 im-
prove 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 signifi-
cantly affect the bevel angle. Reducing standoff
will generally result in a more square cut.