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SPECIAL
ALUMINIUM SMELTING INDUSTRY
Anode slot cutting in progress
Brochot slot cutting machine during installation at Nalco
strong, rigid frame which supports an anode
transport carriage and anode lifts; a powerful
gearmotor which directly drives the shaft
mounted cutting tool discs; entry and exit roller
conveyors; and a fully enveloping enclosure
to retain carbon dust within the machine
whilst assuring operator safety.
Slot parameters
The machine delivered to Nalco can cut a variety
of slot configurations including horizontal
slot depth, as well as sloped slots up to 450
mm deep. In this machine the slot cutting unit
is in a fixed mounting configuration. Brochot,
as mentioned below, can deliver other slots
Brochot slot cutting unit
dimension as well. This simple and robust
solution is well adapted to the client’s needs.
Brochot can also offer machine configurations
with mobile slot cutting unit mountings, where
the cutting discs can be raised or lowered.
The position of the slots in the anode is normally
predefined by the client, but nevertheless
the distance between the slots may be
modified by changing the disc mounting spacers.
To help the gas bubbles to leave the slots
more quickly, the slot depth is often inclined.
This parameter can be quickly and easily
changed in the Brochot machine by adding or
removing spacers on the anode support pads
of the transport carriage. This operation inclines
the anode relative to the machine chassis,
so that the depth of cut is greater at one
end of the anode than at the other.
We emphasise that Brochot is manufacturing
in-house its own blade which is designed
for the specific application of each customer.
The stability of the slot cutting discs is very
important for reliable operation of the slot
cutting machine. Disc diameters for deep slots
become very large compared to the disc thickness.
One of the objectives of slot cutting is to
create a significantly narrower slot than in a
moulded anode. The disc stability is related
to its thickness, materials,
detail design and
fixing arrangements.
Any deformation of
the cutting discs will
cause premature wear
to cutting tools, with
localised tool heating,
and will create slots
that are wider than
desired. The design of
the Brochot disc ensures
excellent shape
stability despite the
mechanical loads and the thermal variations
caused by cutting anodes which are still hot,
particularly in their cores. For Nalco Brochot
has produced tooling which produces an 11.5
mm wide inclined slot with two slots per anode.
Brochot can also offer machines with slot
depth up to 450 mm with small slot widths.
Brochot offers a fully automated process
machine adapted to the products defined by
a particular smelter or anode production unit.
Within the limitations of the machine size
determined at the outset, the machine can be
adapted to accommodate changes in slot dimensions
(depth, length, slope, fully traversing
or partially traversing slots, distance between
slots) when production parameters change.
Tooling life
Operating costs of slot cutting machines depend
largely on the life of the cutting tools.
Brochot has worked over a number of years
to choose and refine the specification of the
cutting tools in order to achieve long life and
reliability. A single set of tool tips can reliably
achieve a life of 40,000 anodes (Customer reports
having achieved 45,000 anodes), and by
indexing the tool tips, the life of the tools can
be doubled. The Brochot tooling design uses
special tool holders carrying diamond tip tools
which are mounted alternately on either side
of our tool carrying discs. Brochot supplies the
complete machine and tooling package with
after-sales service, giving full support for supply
of consumables and replacement parts.
In any slotting operation the rigid mounting
of the anode is essential to avoid problems
of vibration during the machining operation.
The Brochot machine has a rigid anode transfer
carriage equipped with strong pneumatic
anode clamps. A motorised roller conveyor
delivers the anodes to the machine and places
above an anode lift. The lift raises the anode,
allowing the transfer carriage to position itself
around the anode. The lift retracts, lowering
the anode onto the anode support pads, and
then the carriage anode clamps fix the anode
securely in place. The carrier advances the anode
so that the discs cut the slots in the anode
as the carriage advances. After exiting the cutting
zone, the anode clamps release the anode
and the exit lift lowers it onto the outlet roller
conveyor. During this stage, the next cutting
anode is loaded and lifted, ready for the re-
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