Tweco Ultra-Cut Torch Data - Manual (Page 2)

TORCH DATA for Ultra-Cut 8-2 Manual 0-4828 Rev BA
Ohmic Sensing
Ohmic sensing is not recommended with water shield. Water on the plate interferes electrically with the ohmic
sensing circuit.
Direction of Cut
The plasma gas stream swirls as it leaves the torch to maintain a stable arc column. 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
Scrap
Clockwise
Counter-
Clockwise
Art # A-04182
Workpiece
Scrap
Side Characteristics Of Cut
To make a square - edged cut along an inside diameter of a circle, move the torch counterclockwise around the
circle. To keep the square edge along an outside diameter cut, move the torch in a clockwise direction.
Underwater Cutting
Cutting on a water table either underwater or with the water touching the plate or with a water muffler system is not
recommended. If a water table is used the water level must be a minimum of 4 inches / 100 mm from the bottom
of the plate. Failure to follow this recommendation could result in poor cut quality and short consumable parts life.
Bevel Cutting Definitions
Bevel Angle The angle between the center line of the torch and a line that is perpendicular to the work-
piece. If the torch is perpendicular to the workpiece, the Bevel Angle is zero. The maximum
Bevel Angle is 45°.
Nominal Thickness The vertical thickness of the workpiece.
Effective Thickness The length of the cut edge, or the distance the arc travels through the material while cutting.
Effective Thickness is equal to the nominal thickness divided by the cosine of the bevel
angle. Effective Thicknesses are listed in the cut chart.
Clearance The vertical distance from the lowest point of the torch to the surface of the workpiece.
Effective Cut Height The linear distance from the center of the torch outlet to the workpiece surface along the
torch center-line. A range of Effective Cut Height distances are listed in the cut chart. The
smallest number is for a straight cut (bevel angle = 0°). The largest number is for a 45° bevel
cut with a clearance of 2 mm (0.125 in).
Arc Voltage The Arc Voltage setting is dependent on the Bevel Angle and the setup of the cutting system.
The Arc Voltage setting on one system may be different from a second system even if the
workpiece is the same thickness. The arc voltages for bevel cutting are not supplied in the
bevel cut charts.