REHM TIGER DIGITAL 180 AC/DC ULTRA, Operating Instructions Manual

Page: 26 / 83

Function description
26
t
t
2-Takt-Intervall
Brennertaster 1
Gasventil
Schweißstrom
t
Fig.13 Process for 2 cycle interval

1 cycle: Actuate the torch trigger
The set gas pre-flow time expires, the gas valve opens. After the
gas pre-flow time has expired the arc is ignited.
The welding current automatically adjusts to the starting current.
After expiration of the current slope-up time the welding current
reaches the preselected value I1. The set interval welding time
expires.
After the interval welding time expires the current reduces
according to the preselected slope-down time to the value set for
the end crater current and automatically switches off after expiry of
the end current time, i.e. the welding current goes to 0A. The inert
gas flow is according to the chosen gas post-flow time, and the
pause time.
The welding current then reverts to the preselected starting current
and the welding process continues as described.

2 cycle: Release the torch trigger
Interval welding ceases.
5.3 High-frequency (HF) ignition
The corner button operating modes [ BF3 ] is used to activate the 2 and 4 cycle
processes with HF ignition.
5.3.1 Welding with HF ignition
REHM TIG welding machines are equipped with RF igniter. HF ignition is
automatically switched off in the "electrode" setting.
HF ignition makes contact-free ignition of the arc between the electrode and
workpiece through pre-ionization of the air gap for DC and AC welding possible,
whereby tungsten inclusions and therefore welding defects are prevented. In
either case, the HF ignition unit is automatically switched off again after ignition.
Re-ignition of the arc described in Section 6.2.2 when AC welding is performed
without using the HF ignition unit. This reduces the electrical noise emission and