Castolin SynARC 180 Mode D'emploi page 44

CASTOLIN SynARC 180 & SynARC 200
to implement welding. Common arc ignition mode includes scraping mode and striking mode. (See Fig.10)
During welding, touch the surface of the weldment with the end of the electrode by scraping or light
striking to form short circuit, and then quickly lift the electrode 2~4mm away to ignite arc. If arc ignition
fails, it is probably because there is coating at the end of the electrode, which affects the electric
conduction. In this case, the operator can strongly knock the electrode to remove the insulation material
until the metal surface of the core wire can be seen.
4. Tack weld
For fixing the relative positions of the two pieces of weldment and welding conveniently, 30~40mm short
weld joints are welded every certain distance in order to fix the relative positions of the weldment during
welding assembly. This process is named as tack weld.
5. Electrode manipulation
The electrode manipulation actually is a resultant movement in which the electrode simultaneously moves
in three basic directions: the electrode gradually moves along the welding direction; the electrode
gradually moves toward the weld crater; and the electrode transversely swings. (See Fig.11) Electrode
should be correctly manipulated in three movement directions after arc is ignited. In butt welding and flat
welding, the most important is to control the following three aspects: welding angle, arc length and welding
speed.
⑷ Welding angle: the electrode should be inclined in 70～80º forwards. (See Fig.12)
⑸ Arc length: the proper arc length is equal to the diameter of electrode in general.
⑹ Welding speed: proper welding speed should make the crater width of the weld bead about twice
the diameter of the electrode, and the surface of the weld bead should be flat with fine ripples. If
the welding speed is too high, and the weld bead is narrow and high, the ripples are rough, and
the fusion is not well implemented. If the welding speed is too low, the crater width is excessive,
and the workpiece is easy to be burned through. Besides, current should be proper, electrode
should be aligned, arc should be low, and welding speed should not be too high and should be
kept uniform during the whole welding process.
a)
striking mode
Fig10 Arc ignition modes
b)
scraping mode