Tweco 1000 CE Merlin - Manuel (Page 40)

OPERATION 4-6 Manual 0-2731
K. Pressure and Flow Settings
Move the RUN/SET switch to SET position. Set
plasma and secondary pressures. Set the desired gas
pressures and flows at the Gas Control Front Panel
as follows:
1. Select the desired plasma and secondary gases by set-
ting the Gas Control Module front panel switches to
the desired gas positions.
2. To set the Plasma Gas pressure and flow rate do the
following:
a. Fully open the valve on the top of the Plasma Gas
flowmeter.
c. Pull out the knob on the Plasma Gas regulator.
d. Turn the knob clockwise to increase or counter-
clockwise to decrease gas pressure.
e. Push the knob back in to lock the pressure setting.
f. Slowly close the valve on the top of the Plasma Gas
flowmeter until the desired flow rate is achieved.
3. To set the Secondary Gas pressure do the following:
a. Set the Secondary Mode Selector switch to Sec
Pressure position.
b. Pull out the knob on the Secondary Gas regu-
lator.
c. Turn the knob clockwise to increase or coun-
terclockwise to decrease gas pressure.
d. Push the knob back in to lock the pressure set-
ting.
4. To set the Lo-Flow Gas flow rate do the follow-
ing:
a. Set the Secondary Mode selector switch to Lo-
Flow Gas position.
b. Fully open the valve on the top of the Lo-Flow
Gas flowmeter.
c. Pull out the knob on the Secondary Gas regu-
lator.
d. Turn the knob clockwise to increase or coun-
terclockwise to decrease gas pressure.
e. Push the knob back in to lock the pressure set-
ting.
f. Slowly close the valve on the top of the Lo-
Flow flowmeter until the desired flow rate is
achieved.
5. Set the Water (H
2
O) Mist flow rate as follows:
a. Set the Secondary Mode selector switch to H
2
O
Mist position.
b. Slowly open the valve on the top of the H
2
O
Mist flowmeter until the desired flow rate is
achieved.
6. Place the RUN/SET switch to the RUN position.
NOTE
For recommended gas pressures and flows for vari-
ous cutting operations refer to the Instruction
Manual, 0-2710, supplied with the Maximizer 300
Torch.
L. Ready for Operation
Return the RUN/SET switch to RUN position. The
system is now ready for operation.
NOTE
Refer to Appendix 2 for a detailed block diagram of
the Sequence of Operation.
4.06 Cut Quality
Cut quality requirements differ depending on applica-
tion. For instance, nitride build-up and bevel angle may
be major factors when the surface will be welded after
cutting. Dross-free cutting is important when finish cut
quality is desired to avoid a secondary cleaning opera-
tion.
The following cut quality characteristics are illustrated
in Figure 4-7:
Cut Surface
The condition (smooth or rough) of the face of the
cut.
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.
Dross Build-up and Top Spatter
Dross is molten material which is not blown out of the cut
area and re-solidifies on the plate. Top spatter is dross
which accumulates on the top surface of the workpiece.
Excessive dross may require secondary clean-up opera-
tions after cutting.