Plasma 25ci
Operating manual
Page 19
20. Preparations for cutting
1 Equipping the torch
Fit a plasma nozzle according to manufacturer's instructions respectively the at the main switch or step switch
given data into the torch. If the hole of the nozzle is too big, the power and quality of the cut decreases. If it is too
small, the plasma nozzle is overstressed and gets damaged.
Plasma nozzle and electrode are wear parts. A plasma nozzle with a badly burnt-out hole and an electrode with a
large penetration crater involves worse cutting quality and striking characteristics. These parts must be
exchanged by original wear parts.
At the exchange of wear parts take care that they are tightened fastly.
Recommended nozzle diameter:
from 7A to 18A
from 19A to 25A
Diameter
0,65mm
0,8mm
21. Cutting
1 Pilot arc ignition
Bring the nozzle of the cutting torch to the starting point of the cut to be executed.
Press torch trigger. After a short preweld gas flow time (0,5s) the pilot arc is ignited, and at the instant of the pilot
arc impacting the work piece, the cutting arc is formed.
In the event of a cutting arc failure, the pilot arc is switched off after approx. 4 sec.
Repeated ignition of the pilot arc without actually initiating a cutting process should be avoided. An
overload of the pilot arc resistance might occur, resulting in unnecessary wear of the torch parts.
2 Cutting
In a hand-operated cutting process, move the torch with light contact over the work piece at a constant speed.
For achieving an optimum cut, make it a point to keep the right cutting speed correspon-ding with material
thickness. If the cutting speed is too low, a blunt cutting edge will be the result because of the unduly high
thermal input. Optimum cutting speed becomes apparent when the cutting jet slightly slopes backwards.
At the instant of releasing the torch trigger, the plasma jet is extinguished and the current source cut off. The gas
is post-flowing for approx. 1 minute to cool the torch.
Overshooting the work piece at pressed torch trigger will initiate the same procedure.
The machine must not be switched off during gas post-flow. Danger of torch damage by
overheating!
In hand-operated hole-piercing, the hand cutter must be held in an inclined position and then slowly brought to a
vertical position to avoid the formation of spatter.
