Implementation of Metal Casting Best Practices - EERE - U.S. ...

I. Aluminum Casting Facility-1
Plant Profile
Aluminum Casting Facility-1 produces castings for a variety of products including engine
products, exercise equipment, and power tools. It produces 40 million pounds of aluminum
castings per year and employs a variety of casting processes including die, permanent mold, sand,
lost foam, and pressurized lost foam. Due to the size of this facility, the analysis focused on the
pressurized lost foam operation. However, senior management did provide the assessment team
with an example of a benefit they experienced by incorporating the results from a Metal Casting
R&D project into its die casting operation.
The 20,000 square feet pressurized lost foam facility is highly automated. The steps in the
operation process are similar to traditional lost foam, although there are a few additional steps.
The process begins with fabricating patterns from polystyrene beads. The patterns are then
coated with a carefully controlled refractory material by dipping them into a slurry. Once the
coating has dried, the patterns are placed into a drum-like flask and packed in molding medium
via a programmed vibratory system which fills the space between the pattern and the flask walls.
A robotic arm then picks up the flask and places it into one of the pressure vessels. Once inside
the pressure vessel, another robotic arm pours the aluminum into the vessel, and the polystyrene
pattern begins to vaporize. The molten metal is delivered to the lost foam pressure line using a
launder system and is held in a natural gas-fired reverberatory furnace. Once pouring is complete,
the lid of the vessel is closed and 150 psi of pressure is applied for 15 minutes as the casting
solidifies. A robotic arm removes the solidified casting from the vessel and quenches it in water.
The casting then automatically moves to the cleaning and finishing room. 60
Aluminum Casting Facility-1 has a staff dedicated to identifying opportunities for energy savings,
and implementing projects to achieve these energy savings. The annual energy bill for the entire
plant is approximately $10 million per year mostly attributable to the need to melt, hold, and
distribute molten metal. 61 The plant has an active program in place to identify compressed air
leaks and identify any other wasteful practices, and has installed high-efficiency lighting and
motors. The furnaces and the launder system were properly insulated and covered.
Onsite Assessment
The format of the site visit followed the same as the others. The facility was aware of the
services offered by IAC that are part of the ITP BestPractices subprogram. However, due to its
large size, it does not qualify for IAC’s services. As the assessment team found at other plants,
the management at Aluminum Casting Facility-1 was unaware of the free suite of BestPractices
software tools. They also were unaware of the Save Energy Now efforts. Learning about their
benefits, Aluminum Casting Facility-1 decided to apply for an Energy Savings Assessment
(ESA) of both its die casting and lost foam facilities. They were awarded however at the time of
drafting this report the assessment results were not yet available.
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