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

, .

1. I. S. Pinchuk, et al. : Stablization of transfer and methods of

reducing the spattering of metal in COwelding with a

short arc, Welding Production, 27-6 (1980), 9-14

2. E. K. Stava : The surface tension transfer power source,

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

Guide, 37-330, (1997), 8 (in Japanese)

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 : ysys032@kitech.re.kr

()

1965

,

, ,

e-mail : hsryoo@kitech.re.kr

9. J. H. Waszink, L.H.J. Grat : Der Einflues der Sasstroemung

auf die Tropfenabloesung beim plasma-MIG Scheisseu,

Grosse Schweiss technische Tagung, DVS Verichte,

(1977), p.198

10. The physics of welding, IIW, ed. by J. F. Lancaster,

Pergammon Press, (1984), 234-237

11. J. C. Amson : An analysis of the gas-shielded consumable

metal arc welding system, Brit. Welding J., 41-4(1962),

232-249.

12. J. H. Hwang, H. S. Moon, S. J. Na and K.S. Han, A study

on modeling of short-circuiting phenomena and selection of

current waveform for reduction of spatter in GMAW,

Welding J. KWS, 14(1996), 57-63 (in Korean)

13. C. H. Lee, H. J. Kim, B. Y. Kang : Effect of delay time

control on the spatter generation in COwelding, Journal

of KWS, 17-5(1999), 61-68 (in Korean)

14. H. J. Kim, Y. S. Kim : Concept of waveform control for

the reduction of COwelding spatter, Welding J. KWS,

16-3(1998), 18-28 (in Korean)

15. T. Mita : Waveform control method in COgas shielded

arc welding, Quarterly Journal of the Japan Welding

Society, 6-2(1998), 209

16. DAIHEN Inc. : DP400/DP500/DM350 Digital controlled DC

inverter arc welding machines, CAT. NO. A446A

17. M. J. M Hermans, G. Den Ouden : Process behavior and

stability in short circuit gas metal arc welding, 78-4(1999),

p. 8

18. H. J. Kim, C. H. Lee : The Characteristics of power sources

on the spatter generation rate in CO2 arc welding process,

Journal of KWS, 17-4(1999), 16-21 (in Korean)

19. T. Mita : Spatter reduction-power source considerations, Welding

International, 5-11(1991), 847-850

()

1953

,

,

e-mail

:

kimhj@kitech.re.kr

()1958 ,

,

,

Power

Supply

,

Simulation

e-mail

:

scoh@kut.ac.kr

1. 2. 3. 4. 5. 6.