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ALUMINIUM SMELTING INDUSTRY
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Others
This paper was presented at the ICSOBA Conference
in Belèm-Brazil, 2012
Author
Dipl.-Ing. Berthold Hohl is manager Carbon Technology
of Maschinenfabrik Gustav Eirich GmbH &
Co KG, based in Hardheim, Germany.
HMR’s automated stud repair line
I. Dal Porto, HMR Hydeq
The consumption of yoke studs is huge in
aluminium smelters. Today most of the
plants carry out the repair process manually.
The operation consists of removing
the damaged anode yoke from the overhead
conveyor, transport to the repair
shop, cutting off damaged studs with a
cutting torch, making a seam, adjusting
and welding of new parts – all these operations
are carried out manually. This
traditional manual repair cannot be costeffective
and cannot ensure a high quality
standard, since it involves handling and
transportation of the anode yoke and it
relies on the ability of a human operator
both for welding and for the cut, which
usually employs flame cutting. Flame cutting
results in damage to the surface which
is then needed for welding, whereas it is
very important to reduce the electrical
resistance of the welded joint. Poor quality
cut surfaces can significantly affect the
overall current efficiency of the electrolytic
process and hence production costs.
Automated stud repair line
HMR’s Automated Stud Repair Line (ASRL)
repairs anode yokes by replacing worn-out
studs with the new studs whilst anode yoke
and rod is still on the powered and free conveyor
in the rodding shop. The repair line is
fully automatic and requires only one operator.
The operation starts by testing of every anode
stud on the anode yoke in accordance with
the wear-and-tear specification set up by the
customer. Anode studs with wear and tear
above the acceptable limits are diverted on a
bypass to the ASRL for replacing. The powered
and free conveyors bring the anode rod
forward, first to the cleaning station, then to
the cutting station, where a saw cuts the exhausted
stud from the yoke, and finally into
the welding station, where fully programmable
welding robots perform a perfect weld.
After the replacement of worn anode studs,
the anode yoke with rod returns to the rodding
shop.
During the process of cleaning the studs to
remove bath, rust, oxide scale, etc., some dust
© HMR
Automated Stud Repair Line (ASRL) installed in Årdal, Norway, with sawing station on the right. Data from the measuring station is transferred to the sawing
station, which performs cutting automatically in accordance with the given information.
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