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460 Journal of KWJS, Vol. 25, No. 5, October, 2007
4
A Review of Welding Current Waveform Control and Mechanical Control Technique for Reduction of Spatter in Short Circuit Transfer
Young-Sam Kim, Hoi-Soo Ryoo, Hee-jin Kim and Sung-Chul Oh
1.
GMA(gas metal arc)
.
GMA (
),
.
,
.
,
. 1980 Pinchuk
1) ,
1990 Lincoln STT
(surface tension transfer)2-3)
SENSARC4) .
1).
,
,
.
.
,
. 1980
5),
.
(step motor) (servo motor)
2000
Fronius CMT(cold metal transfer)6-7)
Jetline
CSC(controlled short circuit)8)
.
10~20%
6).
,
.
2.
2.1
GMA (metal transfer)
(consumable electrode)
() (weld pool)
. (internal force)
(surface tension force, )
,
(external force)
. Fig. 1
(gravitational force, ),
(electromagnetic force, ) (plasma
drag force, ) , 4
9).
25 5, 2007 10 461
5
F
Fd
Fem
FG electrode
dropletF
Fd
Fem
FG electrode
droplet
Gravitational force,
Surface tension force,
Electromagnetic force,
Plasma drag force,
Fig. 1 The forces acting on the droplet9)
Forc
e(1
0-
3N
)
4
3
2
1
0
-1
0 50 100 150 200 250
Current(A)
calculated fromthe results of
Pintard (1966a)
Fd
FF G
FF
FemFem
Fem(calculated)
Fig. 2 The forces acting on the drop at the carbon steel9)
Fig. 3 Current flows through the conduction zone, but not
through the rest of the drop surface. The conducti
on zone is described by the angle 11)
(1) (static force
balance model) 10),
Fig. 2
9).
(1)
, (neck)
, (2) 10).
(2)
, Fig. 3
. Fig. 2
, 250A .
.
(pinch effect) ,
(pinch force) (Lorentz force)
10). Amson
11) Fig. 3
conducting zone(
)
, (3)
.
(3)
I ,
. (geometry factor) Fig. 3
conducting zone
.
,
10) Fig. 4
. Fig. 2
. conducting zone ,
(Fig. 5(a)), Fig. 4
.
(repulsive force)
462 Journal of KWJS, Vol. 25, No. 5, October, 2007
6
0 30 60 90 120 150 180
-2
-1
0
1
F2
Angle ()
rd=1.5Re
rd=2.0Re
Fig. 4 Variation of as a function of 11)
(a) CO2(An active gas) (b) MIG(An inert gas)
Fig 5 Difference of conducting zone as shielded gas
Voltag
e
Time
Curr
ent
Re
a
Voltag
e
Time
Curr
ent
Re
a
(a) (b) (c) (d) (e) (f)
Fig. 6 Schematic illustration of welding waveform and tr
ansfer of the drop in short circuit transfer
0 1 2 3 4 5 6-3
-2
-1
0
1
2
Downward force
F3
Re /a
Upward force
Fig. 7 Variation of with relative size of the droplet
12)
. CO2
,
(repelled
transfer) .
(Fig. 5(b), conducting zone
), Fig. 4
.
MIG
(spray
transfer) .
10)
(plasma jet) ,
, Fig. 2
.
(cathode spot)
. (DCEN)
spot
(DCEP) .
2.2
,
Fig. 6 (a)
.
, 3V
, .
(4)
12).
(4)
a Fig. 6(a)
. (geometry
factor) Fig. 712)
25 5, 2007 10 463
7
0.96450s 0.96475s 0.96525s 0.96575s 0.96625s 0.96650s
(a) Arc explosion
1.05175s 1.05250s 1.05300s 1.05325s 1.05375s 1.05400s
(b) Arc rotation after arc explosion
Fig. 9 High speed images of two types of spatter generation by instantaneous short circuit
Time
Voltag
eC
urr
ent
N.S.C. I.S.C.
TimeTime
Fig. 8 Schematic illustration of the instantaneous short ci
rcuit
Curr
ent
Time
Curr
ent
Time
Curr
ent
Time
Curr
ent
Time
Without control
With control
Curr
ent
Time
Curr
ent
Time
Curr
ent
Time
Curr
ent
TimeDelay time
(a) Current decrease control1,13-14)
Curr
ent
Time
Curr
ent
TimeDelay time
With control
Without control
(b) Delay time control14)
Fig. 10 Waveform control for suppression of occurrence of inst
antaneous short circuit
.
(1) .
3.
3.1
3.1.1
1
,
,
(instantaneous short circuit, I.S.C.) .
Fig. 8 .
, Fig. 9(a)
.
Fig. 9(b)
464 Journal of KWJS, Vol. 25, No. 5, October, 2007
8
0.5 1.0 1.5 2.0
Delay time(msec)
6
5
4
3
2
1
0
Spat
ter
genera
tion r
ate(%
)
Fig. 11 Spatter generation rate on the delay time13)
Curr
ent
Time
Curr
ent
Time
(a) current rise rate control (b) Peak current control
Fig. 12 Schematic illustration of the current waveform co
ntrol in short circuit period14)
Curr
ent
Time
Fig. 13 Schematic illustration of current rise slope control
at short circuit
.
.
.
Pinchuk1) ,
812V
210A 0.71msec
.
.
Fig. 10(a) .
13) Fig. 11
0.6msec
.
Fig. 10(b) .
3.1.2
(normal short circuit, N.S.C.)
(>1) Fig. 6 (b)
,
,
.
.
(5)
Fig. 6 (d)
.
(5)
, (
)
.
.
, Fig. 12(a)
,
Fig. 12(b)
,
14).
Fig. 13 Fig. 13
,
. Fig. 13
,
Fig. 14
25 5, 2007 10 465
9
1.52825s 1.55775s 1.58800s 1.60700s 1.60850s 1.63150s
Fig. 14 High speed images of spatter generation during the long short circuit period
Curr
ent
Time
Fig. 15 Current waveform control of arc reignition4)
Curr
ent
Time
Fig. 16 DPC(Deposition preventive current) control to proh
ibit the long short circuit period14)
(a) arc (b) short
Fig. 17 Schematic diagram of short circuiting mechanis
m by the weld pool oscillation
.
,
.
.
3.1.3
Fig. 15
3,14).
3.1.4
Fig. 14
( 10msec)
.
Fig. 16
(5)
14-15,19).
3.2
3.2.1 ( )
CO (6)
. ,
(6) .
(6)
Fig. 17(a)
. Fig. 17(b)
>1
466 Journal of KWJS, Vol. 25, No. 5, October, 2007
10
Voltag
eC
urr
ent
Time
Fig. 18 Welding waveform and high speed images of sp
atter generation during the long arc period
Curr
ent
Volt
age
Time
Curr
ent
Volt
age
Time
Curr
ent
Volt
age
Time
Curr
ent
Volt
age
Fig. 19 Schematic illustration of short circuit induction c
ontrol16)
0
Measured short circuit frequency(Hz)
0Cal
cula
ted o
scilla
tion f
requency
(Hz)
50 100 150 200
50
100
150
200
Fig. 20 The calculated oscillation frequency vs. the meas
ured short circuit frequency for conditions of
maximum process stability17)
8.535 8.540 8.545 8.550 8.555 8.560 8.565 8.5700
50100150200250300350400
-505
101520253035
Curr
ent
(A)
Time (Second)
Volt
age (
V)
8.54290s 8.54400s 8.54760s 8.55340s 8.55360s 8.56180s
Fig. 21 Waveform and high speed images of weld pool
oscillation on the current pulse control
.
(3) F2
.
Fig. 18
, ( 1msec) 45V
.
Fig. 19
.
16).
( )
,
(6)
15,19)
.
3.2.2 ()
Fig. 2017)
,
.
(>>1)
. Fig. 21
,
.
25 5, 2007 10 467
11
Fig. 22 A sample of welding current waveform of weldi
ng power source controlled by current wavefor
m - STT3)
0.3 0.6 0.9 1.2 1.5 1.8 2.1
Delay time(msec)
Num
ber
/ 2se
c
100
80
60
40
20
0
I.S.C
N.S.C
Total
Fig. 23 Number of short circuit frequency on the delay t
ime13)
Current
Spat
ter
genera
tion r
ate(%
)
150 200 250 300 350 400
0
1
2
3
4
5
SCR
INVERTER
INVERTER
INVERTER INVERTER
Fig. 24 Spatter generation rates of different power supplie
s18)
(a)
(b)
Fig. 25 Phenomena of burn through and distortion at thin
plate welding
.
4.
, STT(surface tension
transfer)2-3)
SENSARC4) ,
0.5%
. Fig. 223) STT
.
4
,
. , , ,
.
.
, . Fig. 23
13), Fig. 24
(inverter I inverter IV)
18).
.
, .
(5) .
Fig. 25
.
5.
5.1
468 Journal of KWJS, Vol. 25, No. 5, October, 2007
12
Power Source
+-
Work piece
Wire
Feeder
Wire
storage
Welding
wire
MotorMotor Controller
Fig. 26 Schematic illustration of mechanical control system
(a) Fronius - CMT (b) Jetline - CSC
Fig. 27 Mechanical control systems commercial used
Fig. 28 A schematic illustration of welding waveform and
wire feeding control of CMT process7)
.
.
0 ,
. (oscillation)
.
Fig. 1 4 , FM
(mechanical force)
.
5.2
(
) (buffer)
. Fig. 26
.
msec
(
) .
,
,
.
.
Fig. 27(a) Fonius
CMT(cold metal transfer)6-7)
Fig. 27(b) Jetline
CSC(controlled short circuit)8) .
CMT
.
5.3 CMT
CMT 0
,
. Fig. 287) CMT ,
.
Fig. 28
, ,
. ,
0A ,
0A .
. ,
.
CMT 63Hz, 70Hz,
. Fig. 29
CMT
.
.
25 5, 2007 10 469
13
(a) Fillet weld on 1.0mm AlMg3 sheet backing with
welding speed of 2.0m/min
(b) Butt-weld, without weld-pool support, on 0.8mm
AlMg3 sheet
Fig. 30 CMT welding of Al alloy sheets6)
Fig. 31 High speed welding bead shape on steel by CM
T process at welding speed of 3m/min using
the 100% CO2
Time(s)
1.00 1.01 1.02 1.03 1.04 1.05
01020
3040
50100150200250300350400
Voltag
e(V
)C
urr
ent(
A)
: Wire direction
Time(s)
1.00 1.01 1.02 1.03 1.04 1.05
01020
3040
50100150200250300350400
Voltag
e(V
)C
urr
ent(
A)
1.00 1.01 1.02 1.03 1.04 1.05
01020
3040
50100150200250300350400
Voltag
e(V
)C
urr
ent(
A)
: Wire direction
Fig. 29 Welding waveform and high speed images by C
MT process
5.4 CMT
CMT GMA
, , ,
,
.
CMT , ,
0.3mm
. Fig. 30(a) 2m/min
1mm (fillet)
, Fig. 30(b) 1.5m/min
(backing sheet) 0.8mm
(butt)
5). Fig. 31 100% CO2
3m/min 2.3mm
(bead-on-plate) .
/
2m/min
, CMT
Fig. 31
.
5.
,
.
() ,
, ,
0.3mm ,
,
. ,
, ,
, ,
2 ,
,
,
,
.
.
,
.
470 Journal of KWJS, Vol. 25, No. 5, October, 2007
14
.
07
, .
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reducing the spattering of metal in COwelding with a
short arc, Welding Production, 27-6 (1980), 9-14
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new, low-spatter arc welding machine, Welding Journal,
72-1(1993), 25
3. Bruce D. DeRuntz : Assessing the benefits of surface
tension transfer welding to industry, Journal of Industrial
Technology, 19-4(2003)
4. COMAG Power supply SENSARC LS350, KOBE Technical
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5. Lebedev V. A. and Nikitenko V. P. : The clamps for pulsed
feed of electrode wire, Avt Svarka, 10(1984), 52-58
6. K Furukawa : New CMT arc welding process - welding of
steel to aluminium dissimilar metals and welding of
super-thin aluminium sheets, Welding International,
20-6(2006), 440-445
7. Fronius International GmbH : Welding wire storage device,
PCT Appl. No. AT2005000019(2005)
8. G. Huismann : Direct control of material transfer : The
short-circuiting(CSC)-MIG process, Proc. Gas Metal Arc
Welding for 21st Century Conf., Dec. 2000, Orando, FL,
USA, 165
()
1979
e-mail : [email protected]
()
1965
,
, ,
e-mail : [email protected]
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metal arc welding system, Brit. Welding J., 41-4(1962),
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current waveform for reduction of spatter in GMAW,
Welding J. KWS, 14(1996), 57-63 (in Korean)
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arc welding, Quarterly Journal of the Japan Welding
Society, 6-2(1998), 209
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()
1953
,
,
:
()1958 ,
,
,
Power
Supply
,
Simulation
:
1. 2. 3. 4. 5. 6.