CPT International 02/2019

SPECIAL: GIFA 2019
ZPF GMBH
New furnace plant enables simultaneous melting
of aluminium chips and ingots
Due to the different
shapes of ingots, return
material and aluminium
chips, different furnace
types were previously
required for
melting the respective material. However,
separate plants for the different
types of material do not pay off for die
casting foundries with too low volumes
of aluminium chips or return material,
so that only ingots are molten down.
ZPF GmbH, Siegelsbach, Germany, have
now developed a melting furnace
which is qualified for melting down aluminium
chips as well as recycling material
and ingots – a sustainable utilization
of the system is thus always
ensured. The plant is equipped with an
automatic charging system and is able
to melt up to 500 kg raw material per
hour, for example 250 kg aluminium
chips and 250 kg ingots. The new melting
furnace technology will be presented
for the very first time at this
year‘s GIFA with an exhibit.
Production by-products such as scrap
material and runner systems or even
aluminium chips are usually collected
and recycled externally in most foundries,
as they cannot be returned directly
to the melting process for economic
reasons. This results in high costs for
storage and transport, and the logistical
effort should not be underestimated.
“Until now, our aluminium melting furnaces
were only designed for charging
with unmixed material; a material mix
of ingots and recirculation aluminium
parts was previously only possible to a
limited extent due to the desired
boundary parameters such as melting
loss and melting rate“, reports Sven-
Olaf Sauke, head of R & D at ZPF GmbH.
“For some foundries, a pure chip furnace
is uneconomic, since the metal-cutting
share in the cast product is often
too low.“ ZPF has taken this market
need as an opportunity to develop a
new technology for melting furnaces
enabling the simultaneous melting of
chips, ingots or return material while still
keeping the melting loss values at an
extremely low level. This offers companies
greater flexibility in the recycling
process and new opportunities to optimize
the melting process.
For an optimal constructive design
“Since there are two different shapes in the case of chips and ingots, we first had to
choose the main variant“, reports Sven-Olaf Sauke, head of R & D at ZPF GmbH. “For our
prototype, we opted for chips as the main material and designed the furnace as a heel
melter (Graphics: ZPF GmbH).
of the new furnace, simulations were
used in the course of development to
be able to assess the basic system
behaviour. In addition, power and
exhaust gas measurements were carried
out under foundry conditions which
were used to determine the functional
parameters. “The decisive factor for us
was the optimum melting of the metal
and the required temperature control
in the furnace,“ explains Sauke. “In
addition to energy consumption,
numerous other factors that strongly
influence the melting result play a role
here in a modern furnace system - for
example the quality of the raw material
and the melting loss. For practical
implementation, ZPF analysed the data
collected and determined the parameters
required for simultaneous melting
of chips and other aluminium materials.
Based on these results, a prototype with
the new technology was implemented.
The melting furnace has dimensions
of 575 cm x 380 cm x 445 cm (L x W x H)
at an empty weight of approximately
28 tons. It is dimensioned for a maximum
throughput of 500 kg/h in total.
The furnace system is extended by an
automatic charging unit. This modular
unit is designed in such a way that different
types of material can be loaded
according to customer requirements.
“For the simultaneous melting of different
material forms in one furnace,
the first step is to determine the leading
material variant,“ Sauke says. “For our
prototype, we opted for aluminium
chips as the main material and therefore
designed the furnace as a heel melter.
As a result, the chips can be molten
down in combination with return material,
return wheels or ingots“. Which
variant is added to the chips can be
selected by the operator. The only
important thing is to pay attention to
the optimum quantity ratio between
chips and secondary material in order to
achieve optimum melting performance.
The new system will be presented at
this year‘s GIFA in Düsseldorf. “We will
be demonstrating the new system technology
using a furnace at our trade fair
stand. This gives us the opportunity to
present the innovations to interested
users in a detailed and practical manner,“
explains Sauke. Hall 10, Stand F59
www.zpf-gmbh.de
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