Tweco 39 CutMaster - Manual (Page 38)

cutmaster 39
OPERATION 4T-2 Manual 0-4975
NOTE
Refer to Section 6 and the Appendix Pages for
additional information on torch parts.
Change the torch parts for a different operation as
follows:
WARNING
Disconnect primary power at the source be-
fore assembling or disassembling torch parts,
or torch and leads assemblies.
NOTE
The shield cup holds the tip and starter cartridge
in place. Position the torch with the shield cup
facing upward to keep these parts from falling out
when the cup is removed.
1. Unscrew and remove the shield cup assem-
bly from the torch head.
2. Remove the Electrode by pulling it straight
out of the Torch Head.
A-03645
Electrode
Start Cartridge
Tip
Shield Cup
Torch Head
Torch Parts
3. Install the replacement Electrode by push-
ing it straight into the torch head until it
clicks.
4 . Install the starter cartridge and desired tip
for the operation into the torch head.
5. Hand tighten the shield cup until it is seat-
ed on the torch head. If resistance is felt
when installing the cup, check the threads
before proceeding.
4T.05 Cut Quality
NOTES
Cut quality depends heavily on setup and pa-
rameters such as torch standoff, alignment with
the workpiece, cutting speed, gas pressures, and
operator ability.
Refer to Appendix Pages for additional informa-
tion as related to the Power Supply used.
Cut quality requirements differ depending on
application. For instance, nitride build - up and
bevel angle may be major factors when the sur-
face will be welded after cutting. Dross - free cut-
ting is important when finish cut quality is desired
to avoid a secondary cleaning operation. The
following cut quality characteristics are illustrated
in the following figure:
Kerf Width
Cut Surface
Bevel Angle
Top Edge
Rounding
Cut Surface
Drag Lines
Dross
Build-Up
Top
Spatter
A-00007
Cut Quality Characteristics
Cut Surface
The desired or specified condition (smooth or rough)
of the face of the cut.
Nitride Build - Up
Nitride deposits can be left on the surface of the cut
when nitrogen is present in the plasma gas stream.
These buildups may create difficulties if the material
is to be welded after the cutting process.
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.