TIG welding of motorcycle frame parts automated

Automatic pulsed-TIG welding provides relatively high, but accurately controlled heat input and allows gaps to be bridged effectively when welding 25 CrMo4 steel motorcycle frames, said TPS-Fronius.

TPS-Fronius reported that Austrian motorcycle builder, KTM, in Mattighofen is using automated pulsed-TIG welding for joining frame sections for its RC8 bike.

Fronius said that the system offers a 90% degree of automation.

With regard to strength, independent test engineers have declared themselves satisfied with the results.

The results also met the strict criteria of the commercial managers at KTM and the bikers.

The various technical experts have responded positively to the MagicWave 4000 system from Fronius.

The RC8 road bike is one of KTM's latest and most successful models.

Not only do the weld seams need to be strong, they need to look good too.

All the joins in the RC8 frame are therefore TIG-welded (TIG = tungsten inert gas).

The traditional rippled TIG weld seam conveys the sense of prestige and quality that end customers are always looking for, said fronius.

However, the high seam quality that TIG welding provides does have one drawback: relatively low productivity.

This is generally some two-thirds below that achieved using the more modern MAG welding methods (MAG = metal active gas).

* Developing pulsed-TIG automation - KTM's technical experts have devoted three years to this development project, and the end result is 90% automation of frame production.

They eventually made good a significant amount of the productivity shortcomings of TIG compared with the MAG process.

Since the start of 2008, the robot welding plant has been producing RC8 frames at full capacity on a three-shift system.

Production manager at KTM, Josef Baier, said: "This way we can produce particularly fine, clean TIG seams.

The components used are 1.2mm sheets and tubing made from a type of material designated 25 CrMo4.

Our welding system of choice is MagicWave from Fronius".

A special in-house developed pallet feeding system feeds the subassemblies to an ABB robot until the frame is complete.

The effective throat thickness of the fillet and single-V butt welds is 2mm, and the gaps to be bridged are 2mm wide.

The joined tubing sections can withstand the mechanical and dynamic stress of being driven on a road or around a motocross track.

Fronius told manufacturingtalk that the reason that TIG welding is so successful from a technical point of view is its virtually perfect weld toe.

The pulses that are typical of the TIG method cause the filler material to melt on in the form of a series of scallops.

The use in TIG pulse welding of the relatively high, but accurately controlled heat input, allows gaps to be bridged effectively and perfect roots to be achieved.

Fusion at the start and end of a seam is greatly improved, especially when welding tubes.

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