Tweco A80 CutMaster - Manual (Page 38)

CUTMASTER A80
OPERATION Manual 0-4985 4T-4
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.
Side Characteristics Of Cut
To make a square - edged cut along an inside diameter of a
circle, the torch should move counterclockwise 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 commonly
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 cleanup 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 protection. Choose the holding technique that
feels most comfortable and allows good control and
movement.
NOTE
The tip should never come in contact with the
workpiece except during drag cutting operations.
2. Depending on the cutting operation, do one of the fol-
lowing:
a. For edge starts, hold the torch perpendicular to
the workpiece with the front of the tip on the edge
of the workpiece at the point where the cut is to
start.
b. For standoff cutting, hold the torch 1/8 - 3/8 in
(3-9 mm) from the workpiece as shown below.
Standoff Distance
3. Hold the torch away from your body.
4. Slide the trigger release toward the back of the torch
handle while simultaneously squeezing the trigger. The
pilot arc will start.
5. Bring the torch within transfer distance to the work.
The main arc will transfer to the work, and the pilot arc
will shut OFF.
NOTE
The gas preflow and postflow are a characteristic
of the power supply and not a function of the torch.