Tweco 40mm Cutmaster - Manual (Page 39)

CUTMASTER 40mm
Manual 0-5084 4T-7 OPERATION
4T.05 Gouging
!
WARNING
Be sure the operator is equipped with proper
gloves, clothing, eye and ear protection and that
all safety precautions at the front of this manual
have been followed. Make sure no part of the
operator’s body comes in contact with the work-
piece when the torch is activated.
Disconnect primary power to the system before
disassembling the torch, leads, or power supply.
CAUTION
Sparks from plasma gouging can cause dam-
age to coated, painted or other surfaces such as
glass, plastic, and metal.
Check torch parts. The torch parts must cor-
respond with the type of operation. Refer to
Section 4T.07, Torch Parts Selection.
Gouging Parameters
Gouging performance depends on parameters
such as torch travel speed, current level, lead
angle (the angle between the torch and work-
piece), and the distance between the torch tip and
workpiece (standoff).
CAUTION
Touching the torch tip or shield cup to the work
surface will cause excessive parts wear.
Torch Travel Speed
NOTE
Refer to Appendix Pages for additional informa-
tion as related to the Power Supply used.
Optimum torch travel speed is dependent on cur-
rent setting, lead angle, and mode of operation
(hand or machine torch).
Current Setting
Current settings depend on torch travel speed,
mode of operation (hand or machine torch), and
the amount of material to be removed.
Pressure Setting
Even though the setting is within the specified
range, if the torch does not pilot well the pressure
may need to be reduced.
Lead Angle
The angle between the torch and workpiece
depends on the output current setting and torch
travel speed. The recommended lead angle is
35°. At a lead angle greater than 45° the molten
metal will not be blown out of the gouge and may
be blown back onto the torch. If the lead angle
is too small (less than 35°), less material may be
removed, requiring more passes. In some appli-
cations, such as removing welds or working with
light metal, this may be desirable.
35°
Workpiece
Torch Head
Standoff Height
A-00941_AB
Gouging Angle and Standoff Distance
Standoff Distance
The tip to work distance affects gouge quality and
depth. Standoff distance of 1/8 - 1/4 inch (3 - 6
mm) allows for smooth, consistent metal removal.
Smaller standoff distances may result in a sever-
ance cut rather than a gouge. Standoff distances
greater than 1/4 inch (6 mm) may result in mini-
mal metal removal or loss of transferred main arc.
Slag Buildup
Slag generated by gouging on materials such as
carbon and stainless steels, nickels, and alloyed
steels, can be removed easily in most cases. Slag
does not obstruct the gouging process if it accu-
mulates to the side of the gouge path. However,
slag build - up can cause inconsistencies and ir-
regular metal removal if large amounts of material
build up in front of the arc. The build - up is most
often a result of improper travel speed, lead angle,
or standoff height.