23
5.2.4 MMA welding
Under MMA welding for coated electrode, three parameters including hot start current, welding current and
arc-force current are adjustable on digital panel. Hot start current is at “initial segment” of “welding process selection
zone”; welding current is at “process” of “welding process selection zone”; arc-force current is at “MIG arc force, MMA
Arc-force current indication” of “Voltage/arc force/parameters set, etc displaying and setting zone”.
I I
h
I
a
t
h
2s
U U
0
U
VRD
Fig 5.4 MMA processing
1
、
I
h
(hot start current) = I
Δh
(
arc start current
)+ I
a
(welding current); Fixed hot start time: t
h
= 500ms
2
、
I
f
(arc-force current)= I
Δf
(arc-force c I
a
(welding current);Arc-force current should be set based on
electrode diameter, set current and process requirement. With strong arc force, droplet transfer is so fast that it
can be anti-stick, but too strong arc force can increase the spatter; with low arc force, spatter is reduced and
weld bead has nice shape, but arc is weak or electrode is easily stuck. Therefore, arc force should be increased
when welding with thick electrode under low current. Generally, arc force is 20
70 during welding.
3
、
After short-circuit time is over 2s, anti-stick current of 25A comes out until electrode is separated from the
workpiece;
4
、
U
VRD
, VRD of about 15V, conforming to Australian standard 1674.2 2007, is switched off by default. After
being switched off, welder outputs no-load voltage U
0
when MMA welding is not started.
5
、
Model
Hot
start
current
Welding
current
Arc-force
current
Max
current
limit
MIG500P
0~250A
30~500A
0~250A
550A
MIG350P
0~200A
30~350A
0~200A
400A
Note: Max current limit limits I
h
and I
f
.
I
f
地
Summary of Contents for MIG 350P
Page 13: ...11 4 6 2 Separated machine installation Figure 4 3 ...
Page 19: ...17 3 Operation modes Table 5 2 DC MIG operation modes Modes Sketch map 2T 4T ...
Page 20: ...18 Repeat Spot weldin g 5 2 3 Pulse MIG 1 Synergic and Separate ...
Page 22: ...20 2T with initial crater 4T ...
Page 23: ...21 4T with initial segmen t Special 4T pro gram 4T ...
Page 40: ...38 7 Wiring Diagram ...
Page 42: ...40 ...