Telwin Plasma 34 Guia De Inicio Rapido página 12

workpiece (= 3 mm.), press the torch button; after approx.
0.5 seconds (pre-air) the pilot arc is struck (max duration 2
seconds). If the distance is correct, the pilot arc immediately
transfers to the workpiece causing the cutting arc to be
struck.
Move the torch on the surface of the workpiece making
steady progress along the ideal cutting line. Adjust the
cutting speed according to the thickness and the selected
current, and check that the arc coming out of the lower
surface of the workpiece has an inclination of 5-10° to the
vertical in the opposite direction to the cutting direction.
Figure (E) the drawing shows torch position on part
moving forward, arc tilting
- The removal of the torch from the piece or the absence of
material (end cut) causes the immediate interruption of
the arc.
- Interruption of arc (cutting or pilot) is obtained by releasing
torch button.
- Piercing: If you have to make this operation or if you have
to start from the center of the piece, ignite keeping the
torch tilted and bring it to an upright position with a smooth
movement.
- This procedure avoids that returns of arc or melted parts
spoil the hole of the nozzle reducing its functionality.
Figure (F) the drawing shows the starting with
tilted torch
- This procedure prevents arc or melted particles to come
back thus spoiling the nozzle hole and reducing its
functionality quickly.
- Piercing of parts with a thickness of 25 % of max. usuable
foreseen, may be carried out directly.
COMMONEST CUTTING FAUL TS
During cutting operations performance faults may arise
which are not caused by plant malfunctioning but by other
operational faults such as:
a Insufficient penetration or excessive scoria settlement:
-too high cutting speed,
-torch is too tilted,
-piece is too thick,
-electrode and nozzle are worn out.
b Interruption of cutting arc:
-cutting speed too low.
-excessive distance between torch and piece,
-electrode is worn out,
- intervention of the protections
c Tilted cutting (not perpendicular)
-torch position not correct
-asymmetric wear of nozzle hole and/or wrong
assemblage of torch parts.
d Excessive wear of nozzle and electrode:
-air pressure too low,
-contaminated air (humidity-oil),
-nozzle holder damaged,
-excessive pilot arc ignitions in the air.
MAINTENANCE
WARNING !
NEVER ACCESS INSIDE THE MACHINE (P ANEL
REMOVAL) OR TOUCH THE TORCH (DISASSEMBLAGE)
WITHOUT HAVING DISCONNECTED POWER PLUG.
ANY INSPECTION PERFORMED UNDER VOL TAGE
INSIDE THE MACHINE OR INSIDE THE TORCH MAY
CAUSE SEVERE ELECTRIC SHOCKS CAUSED BY
DIRECT CONTACT WITH PARTS UNDER VOL TAGE:
TORCH
Periodically, according to its use or to cutting faults (see
Paragraph 5) verify wear of the par ts connected to plasma
arc:
1. NOZZLE HOLDER (Figure G-1)
Unscrew manually from head of the torch. Clean throughly
and replace if damaged (burns, distortions or cracks). Verify
integrity of superior metal sector (actuator torch safety).
2. NOZZLE (Figure G-2)
Check wear of plasma arc hole and of inner and outer
surfaces.
If the hole is widened compared to its original width or if it is
damaged, replace nozzle. If surfaces are particularly
oxidated clean them with extra fine abrasive paper.
3. AIR DISTRIBUTION RING (Figure G-3)
Verify there are no burns or cracks or that airflow holes are
not obstructed. If damaged, replace immediately.
4. ELECTRODE (Figure G-4)
Replace electrode when crater settling on emitting surface
is about 1,5 mm.
Figure (G) drawing shows exploded view of torch
Figure (H) drawing shows electrode with crater
WARNING !
- Before making any operation to the torch let it cool at least
all along the"postgas" period.
- Except for particular cases it is advisable to replace
electrode and nozzle AT THE SAME TIME.
- Respect assembly order of torch parts (reserved
compared to disassemblage)
- Be careful that distributing is assembled properly.
- Reassemble nozzle holder screwing tightly and manually.
- Never assemble nozzle holder without having assembled
electrode distributing ring and nozzle beforehand.
- Timely and appropriate control procedures on torch
parts are essential for safety and functionality of the
cutting system.
TORCH BODY , HANDLE AND CABLE.
- These parts usually need no particular maintenance with
the exception of a periodic inspection and an accurate
cleaning to be made WITHOUT THE USE OF
SOLVENTS.
In case of damages to the insulation such as breaks,
cracks and burns or even a loosening of electric
conductors, the torch CANNOT BE USED FURTHER
SINCE SAFETY CONDITIONS HAVE NOT BEEN
RESPECTED.
IN THIS CASE, REPAIRING (EXTRAORDINARY
MAINTENANCE) CANNOT BE MADE ON SITE BUT
NEEDS TO BE DELEGA TED TO AN AUTHORIZED
SERVICE CENTER TO MAKE SPECIAL TEST TRIALS
AFTER REPAIRING HAS BEEN EXECUTED.
- In order to keep the torch and cable efficient it is
necessary to follow these precautions:
- DO NOT touch torch and cable with warm or hot parts.
- DO NOT strain the cable.
- DO NOT move the cable on sharp edges or abrasive
surfaces.
- Gather the cable in regular coils if it is too long.
- DO NOT step on the cable.
- 12 -
Fig.G .