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A special shaft geometry makes it possible for the BigStruc furnace to handle return material with an area of up to 2.5 square meters.

'Omnivore' Furnace Accepts Any Charge

Aug. 13, 2018
A shaft melting system designed to accept the challenge of larger pieces and higher volumes that result from lighter materials

Automotive manufacturers’ lightweighting initiatives have far-reaching effects on their suppliers — including foundries and diecasters — and on those enterprises developing technologies used by the suppliers. More specifically, the increasing volume of lighter vehicles in production not only means higher demand for aluminum castings, but it triggers demand for better production technologies involved in casting aluminum components and structures.

In particular, “returns” (aluminum scrap returned to the melting stage as furnace-charge material) poses problems for foundries. Melting furnaces have to handle an increasing volume large, flat cast parts and smaller thin-walled material. That is, the returns reflect the variety of new automotive materials formed by high-pressure aluminum diecasting as a consequence of vehicle lightening strategies.

KS Huayu AluTech is an aluminum automotive foundry in Neckarsulm, Germany, that addressed the “large charge” material problem with a new melting furnace: StrikoWestofen’s “BigStruc” model. Not only can this gas-powered furnace handle return material up to 2.5 meters square, it can melt the aluminum scrap energy-efficiently, even at low bulk densities.

StrikoWestofen developed the BigStruc furnace to handle large stacks of pig iron just as well small, thin-walled return material. “After loading, the shaft of the furnace is closed with a cover called a ‘hot gas baffle’,” according to Peter Reuther, senior vice president for the equipment developer. “It keeps the heat in the shaft, preventing energy from escaping unused.

“It also keeps the melting process efficient even at high-void volumes,” Reuther emphasized.

After charging, the BigStruc shaft is closed
with a hot gas baffle that keeps heat in the
shaft and reduthermal energy loss.


These melting advantages created a convincing proposition for KS Huayu AluTech, an operating unit of Rheinmetall Automotive AG. Its “Total Productive Management” philosophy directs that production processes must be able to operate with minimal operator intervention.

The BigStruc melting furnace was selected because of its potential to reduce plant downtime significantly. Also persuasive were the anticipated low frequency for spare-part replacement, and the reduction in scrap and energy loss during melting.

The metalcaster also appreciated the furnace’s largely autonomous and hassle-free maintenance prospects, the furnace designer’s 24/7 remote-diagnosis offer, the unit’s compliance with environmental regulations, and occupational safety standards associated with the unit.

KS Huayu AluTech selected the BigStruc with an enlarged shaft geometry, a capacity of 9 cubic meters for staging aluminum charge material. This means that large-dimension returns can be melted without the need for an operator or machinery to cut the aluminum into two or more pieces before charging.

In order to load BigStruc at the optimal time during melting sequences and keep the furnace well filled at all times, fill levels are monitored constantly via a laser-tracking system. This system functions even if the shaft cover is closed, according to the developer. Data collected on filling cycles, energy requirements, etc. can be archived and evaluated easily. Data analysis of this information can be used then for continuous improvement efforts, to measure and optimize melting efficiency and productivity.

“Our ‘omnivore’ melts up to 3.5 metric tons of aluminum per hour, 24 hours a day,” Reuther gibed. “It’s always hungry, but it never gets tired.”