Lincoln Electric IM649 manual Figure B-2. Weld Droplet Transfer

Appendix B	STT WAVE SHAPING PRINCIPLES		B-3
		FIGURE B-2. WELD DROPLET TRANSFER.

PEAK

AMPS

TAILOUT

BACKGROUND AMPS

T0 T1 T2 T3 T5 T6 T7

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•From time T0 to T1: Background current is a steady-state current level, between 50 and

(Background Current) 100 Amps that maintains an arc to form a weld bead.

•From time T1 to T2: An arc voltage detector indicates that the arc is shorted; background

(Ball Time) current is reduced for approximately 0.75 milliseconds.

•From time T2 to T3: High current is applied to speed the transfer of molten metal to the

(Pinch)	weld puddle. A dV/dt calculation indicates when fuse separation is
	about to occur; current is reduced to 50 Amps.

•Time T4:Fuse separation occurs at low current. Time T4 is a function of

(Fuse Separation) voltage, and not indicated on the amperage waveform.

•From time T5 to T6: A period of high arc current that melts the electrode back. (Plasma Boost)

•From time T6 to T7: Arc current is reduced from Peak Amps to the Background current

(Plasma)level.

WAVE DESIGNER