Tweco A80-A120 CutMaster - Manual (Page 36)

CUTMASTER A80, A120
OPERATION Manual 0-5119
4T-4
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 cutting
tip whose orifice has become elongated.
4T.05 General Cutting Information
!
WARNING
Disconnect primary power at the source before
disassembling the power supply, torch, or torch
leads.
Frequently review the Important Safety Precau-
tions at the front of this manual. Be sure the
operator is equipped with proper gloves, cloth-
ing, 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 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 signifi-
cantly 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
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.
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 coun-
terclockwise around the circle. To keep the square
edge along an outside diameter cut, the torch
should travel in a clockwise direction.
Dross
When dross is present on carbon steel, it is com-
monly referred to as either “high speed, slow
speed, or top dross”. Dross present on top of the
plate is normally caused by too great a torch to
plate distance. "Top dross" is normally very easy to
remove and can often be wiped off with a welding
glove. "Slow speed dross" is normally present on
the bottom edge of the plate. It can vary from a
light to heavy bead, but does not adhere tightly to
the cut edge, and can be easily scraped off. "High
speed dross" usually forms a narrow bead along
the bottom of the cut edge and is very difficult to
remove. When cutting a troublesome steel, it is
sometimes useful to reduce the cutting speed to
produce "slow speed dross". Any resultant clean-
up can be accomplished by scraping, not grinding.
4T.06 Hand Torch Operation
Standoff Cutting With Hand Torch
NOTE
For best performance and parts life, always use
the correct parts for the type of operation.
1. The torch can be comfortably held in one hand
or steadied with two hands. Position the hand
to press the Trigger on the torch handle. With
the hand torch, the hand may be positioned
close to the torch head for maximum control
or near the back end for maximum heat protec-
tion. Choose the holding technique that feels
most comfortable and allows good control and
movement.