Product information spotArc - Ewm-sales.co.uk

THE NEW DIMENSIONS OF WELDING 

EWM-spotArc ® 

TIG SPOT WELDING 

. . . AND SHEETS ARE JOINED PERFECTLY!

HIGHLIGHTS 

• Universal applications thanks to the option of 

connecting multiple metal sheets, including metal 

sheets of different thicknesses 

• Simple to use - welding only carried out on one 

side 

• Economic solution consisting of standard 

components: 

EWM TIG welding machine, TIG spot welding 

torch and optional spot remote control 

• Machine can also be used for TIG and MMA seam 

welding 

in addition to spot welding! 

• Ergonomic torch design for the best possible 

handling and optimum power utilisation 

©2008 EWM HIGHTEC WELDING GmbH GB_EWM-spotArc 1 09.2008

Benefits of EWM spotArc TIG spot welding 

Surface formation in 

TIG spot welding 

• Better surface formation in comparison to 

resistance welding 

• Flatter spot formation in comparison to 

MAG spot welding 

• Excellent seam quality thanks to 

the minimal heat feeding 

• Very low thermal tensions and 

little distortion thanks to short welding times 

• Ideal for visible joins 

thanks to the clean seam finish 


Applications 

• Spot welding of low-alloy and high-alloy sheet steel up to 2.5mm 

• Multiple metal sheet connections, spot joins on visible metal sheets, tack welding 

• Container construction, switching cabinet construction, machine and vehicle manufacturing, car and 

food industry 


The correct nozzle shape for every join 

Butt joint/lap joint T-joint 

Corner joint Butt joint 

DN (Ø 

mm) 

25 

50 

65 

80 

100 

butt weld fillet weld corner joint butt joint 


Frequently used spot weld types 

EWM-spotArc 

Arc spot welding 

Resistance spot welding 

enclosed 

sections 

not 

possible 

metal sheets 

Two-sided 

One-sided 

metal sheets 


System overview 

CLASSIC-control 

RTP3 required 

by kHz pulsed 

RTP 3 

DC-Welding equipment: 

PICOTIG 220; TRITON 220, 260,400, 500; 

and all TETRIX 

RTP 3 


Basic settings for RTP 3 

CrNi 

Seam type 

butt joint 

lap joint 

fillet weld 

spots 

Carbon-steel 

Sheet thickness 

1 mm/1 mm 

2 mm/2 mm 

1 mm/2 mm 

1 mm/1 mm 

1 mm/1 mm 

2 mm/2 mm 

1 mm/1 mm 

2 mm/2 mm 

Frequency Spot time Current Down slope 

2,5 khz 0,25 sec 70 A 0,9 sec 

2,5 khz 0,25 sec 130 A 0,9 sec 

2,5 khz 0,25 sec 260 A 0,9 sec 

2,5 khz 0,25 sec 320 A 0,9 sec 

2,5 khz 0,25 sec 70 A 0,9 sec 

2,5 khz 0,25 sec 130 A 0,9 sec 

2,5 khz 0,25 sec 120 A 0,9 sec 

2,5 khz 0,25 sec 170 A 0,9 sec 

For all parameters the pulse wave duty cycle is 50:50 

Seam type 


Frequency 

Spot time 

Current 

Down slope 

butt joint 

1 mm/1 mm 

2,5 khz 

0,25 sec 

80 A 

0,9 sec 

2 mm/2 mm 

2,5 khz 

0,25 sec 

150 A 

0,9 sec 

lap joint 

2 mm/2 mm 

2,5 khz 

0,25 sec 

276 A 

0,9 sec 

fillet weld 

1 mm/1 mm 

2,5 khz 

0,25 sec 

70 A 

0,9 sec 

For all parameters the pulse wave duty cycle is 50:50 



COMFORT-control 






SYNERGIC-control 





TETRIX COMFORT- and SYNERGIC control 

Carbon-steel 

Seam type 


Frequency 

Spot time 

Current 

Down slope 

butt joint 

1 mm/1 mm 

automatic 

0,3 sec 

165 A 

0,5 sec 

2 mm/2 mm 

automatic 

0,35 sec 

245 A 

0,5 sec 

lap joint 

1 mm/1 mm 

2,5 khz 

with out activArc 

0,3 sec 

250 A 

0,5 sec 

2 mm/2 mm 

2,5 khz 

with activArc 

0,5 sec 

270 A 

0,5 sec 

fillet weld 

1 mm/1 mm 

automatic 

with activArc 

0,5 sec 

170 A 

0,5 sec 

2 mm/2 mm 

2,5 khz 

with activArc 

0,45 sec 

270 A 

0,5 sec 


TETRIX COMFORT- and SYNERGIC control 

CrNi 

Seam type 


Frequency 

Spot time 

Current 

Down slope 

butt joint 

1 mm/1 mm 

automatic 

0,3 sec 

100 A 

0,5 sec 

1 mm/1 mm 

2,5 khz 


0,3 sec 

100 A 

0,5 sec 

2 mm/2 mm 

2,5 khz 

with activArc 

0,35 sec 

180 A 

0,7 sec 

lap joint 

1 mm/1 mm 

automatic 

with activArc 

0,4 sec 

200 A 

0,1 sec 

1 mm/1 mm 

2,5 khz 


0,4 sec 

200 A 

0,1 sec 

2 mm/2 mm 

2,5 khz 

with activArc 

0,5 sec 

270 A 

0,5 sec 

fillet weld 

1 mm/1 mm 

automatic 

with activArc 

0,5 sec 

150 A 

0,1 sec 

2 mm/2 mm 

2,5 khz 

with activArc 

0,5 sec 

250 A 

0,3 sec 


Spot technology, fast, low-voltage – 

Spot welding with tungsten shielding gas 

by Heinz Lorenz, Mündersbach, Germany 

Introduction 

In mechanical engineering, switch cabinet 

construction, car construction, as well as in various 

other sectors, such as the manufacture of household 

appliances, including refrigerators, washing machines 

etc., there are many welding tasks in which thin 

panels need to be welded on one side using a spot 

welding technique. These welds can also be 

performed using resistance spot welding. If the point 

to be welded is only accessible from one side, the 

electrodes are aligned with one another on one side of 

the workpiece in this process, and the metal sheets lie 

on a copper base, Figure 1 [1]. However, accessibility 

is often so restricted that it is not even possible to 

One-sided 

spot welding 

(RPE) 

copper base 

impressions in the heated surface of the metal sheet. 

Resistance welding systems also need to be 

available, which is not the case at every site. Arc spot 

welding machines, on the other hand, can also be 

used for seam welding and therefore provide universal 

usage. 

In comparison to MIG/MAG spot welding, tungsten 

shielding gas welding offers the advantage of 

improved spot surfaces. As the welding can be 

performed without filler material and is only melted 

onto the parent material, the welded points produced 

are particularly flat and smooth. This is a significant 

benefit, especially on visible areas. In addition, the 

heat feeding is very low thanks to the short welding 

times, and this results in very low thermal stress and 

low distortion on the workpieces. 

Systems for tungsten shielding gas spot welding 

Standard inverter power sources (Figure 3) can be 

used for TIG and spot welding, fitted with special 

torches (Figure 4). 

Figure 1 Principle of one-sided resistance spot welding [1] 

insert the copper base underneath, and therefore 

resistance welding cannot be performed. For many 

years, variations of the arc welding process have 

therefore been used for one-sided spot welding on 

thin metal, such as MIG/MAG, TIG (Figure 2) and 

Figure 2 Principle of TIG spot welding 

more recently the plasma process. Especially for 

tungsten shielding gas spot welding, there have been 

recent developments in terms of the power sources, 

controls and torches, which make this process easier 

to use and which improve the quality of the spots. 

Advantages of arc spot welding 

The surface formation produced on the welding points 

is one argument against the use of one-sided 

resistance spot welding. To position and fix the metal 

sheets sufficiently well on the copper base, a higher 

pressure needs to be used that can cause 

Figure 3 Modern inverter power source Foto: EWM 

A spot/pulse remote control (Figure 5) ensures high 

quality, reproducible results thanks to the adjustable 

spot welding time and the optimum preset pulse 

parameters. 

Welding with current pulses offers the advantage that 

deeper fusion penetration is produced during the 

pulse phase, and a certain level of cooling is achieved 

early on in the longer lasting base current phase, 

which permits good fusion penetration and low heat 

loading of the material. 

© 2006 EWM HIGHTEC WELDING GmbH 1/2

Applications 

The process can be used for tacking (Figure 7), and 

Figure 4 spotArc-spot welding torch, water cooled 

The torches are especially important here as well. 

These have feet or specially shaped ends on the 

shielding gas nozzle, which can be placed on the 

surface of the metal sheet during welding. They permit 

to maintain a constant distance between the torch and 

Figure 7 Tack welding with spotArc-spot welding machine 

for joint welding steel sheets and CrNi alloys up to a 

thickness of around 2.5 mm. Metal sheets of different 

thickness can also be welded on top of one another. 

As this is a one-sided process, it is also possible to 

weld on hollow components, such as round or square 

pipes. 

In arc spot welding, the arc melts through the upper 

sheet and the lower sheet is melted onto it. This 

produces flat, fine-textured welding points (Figure 8) 

which require little or no finishing work, even in visible 

areas. 

Figure 5 Remote control for TIG spot welding Foto: EWM 

workpiece, and thus also a constant arc length, which 

contributes to reproducibility of the welding results. At 

the same time, the gas nozzle attached can be used 

to exert force onto the surface, which presses the 

parts being joined against one another. This 

contributes to the high quality of the welding points 

and to the workpieces keeping their correct 

dimensions. These special shielding gas nozzles are 

available for butt welds, fillet welds and corner joints 

(box welds). Figure 6 shows various gas nozzle 

shapes for tungsten shielding gas spots. 

Figure 8 View of the surface using TIG-spot welding 

Literature: 

[1] Killing, R. and H. Lorenz: Kompendium Schweißtechnik 

Band 1 – Verfahren der Schweißtechnik Fachbuchreihe 

Schweißtechnik Band 128/1 (Compendium of Welding 

Technology Volume I – Welding Processes, Specialist Book 

Series, Volume 128/1), DVS-Verlag Düsseldorf 2002 

butt weld fillet weld edge weld 

Figure 6 Spot welding nozzle for different groove shapes 

© 2005 EWM HIGHTEC WELDING GmbH 2/2

For more information please visit our website at 

www.ewm.de 

EWM HIGHTEC WELDING GmbH 

Dr. Günter-Henle-Straße 8 · D-56271 Mündersbach 

Fon +49 2680 181-0 · Fax +49 2680 181-244 

www.ewm.de · info@ewm.de 

EWM Tschechien / EWM Czech Republic 

EWM HIGHTEC WELDING s.r.o. 

Tr. 9. kvetna 718 · CZ-407 53 Jirikov 

Fon +420 412 358-551 · Fax +420 412 358-504 

www.ewm.cz · info@ewm.cz 

EWM HIGHTEC WELDING Sales s.r.o. 

Niederlassung Sales & Service / Sales & Service Branch 

Prodejní a poradenské centrum 

Tyršova 2106 · CZ-256 01 Benešov u Prahy 

Fon +420 317 729-517 · Fax +420 317 729-712 

www.ewm.cz · sales@ewm.cz 

EWM China 

EWM HIGHTEC WELDING (Kunshan) Ltd. 

No. 601 Hengchangjing Road Zhoushi Development Zone, 

CN-215337 Kunshan / Jiangsu 

Fon +86 512 57867188 · Fax +86 512 57867182 

www.ewm.cn · info@ewm.cn 

EWM Handel / EWM Sales 

EWM SCHWEISSTECHNIK-HANDELS GmbH 

Hauptsitz / Headquarters 

In der Florinskaul 14-16 · D-56218 Mülheim-Kärlich 

Fon +49 261 988898-0 · Fax +49 261 988898-20 

www.ewm-handel.de · info@ewm-handel.de 

EWM SCHWEISSTECHNIK-HANDELS GmbH 

Niederlassung Köln / Cologne Branch 

Sachsstraße 28 · D-50259 Pulheim-Brauweiler 

Fon +49 2234 697-047 · Fax +49 2234 697-048 

www.ewm-handel.de · nl-koeln@ewm-handel.de 

EWM Österreich / EWM Austria 

EWM HIGHTEC WELDING GmbH 

Scharnsteinerstr. 15 

A-4810 Gmunden, Österreich 

Fon +43 7612 77802-0 · Fax +43 7612 77802-20 

www.ewm.at · office@ewm.at 

© 

EWM HIGHTEC WELDING GmbH 2008 · EWM-spotArc® · WM.0457.01 · 10.2008 · We reserve the right to make amendments 

Sales, Consulting, Service

Product information spotArc - Ewm-sales.co.uk

Create successful ePaper yourself

Delete template?

Save as template?