Evaporative-pattern casting
Evaporative-pattern casting is a type of casting process that uses a pattern made from a material that will evaporate when the molten metal is poured into the molding cavity. The most common evaporative-pattern material used is polystyrene foam.{{harvnb|Degarmo|Black|Kohser|2003|p=321}}.
The two major evaporative-pattern casting processes are:
The main difference is that lost-foam casting uses an unbonded sand and full-mold casting uses a bonded sand (or green sand). Because this difference is quite small there is much overlap in the terminology. Non-proprietary terms that have been used to describe these processes include: cavityless casting,{{US Patent|4068704}}. evaporative foam casting, foam vaporization casting, lost pattern casting, the castral process, and expanded polystyrene molding.{{harvnb|American Society for Metals|Stefanescu|ASM International Handbook Committee|ASM International Alloy Phase Diagram Committee|1991|p=229}}.{{harvnb|Totten|Funatani|Xie|2004|p=357}}. Proprietary terms included Styro-cast,{{Citation | title = Styro-cast | url = http://www.efpcorp.com/markets/styrocast.php | access-date = 2009-03-29 }}{{Dead link|date=August 2019 |bot=InternetArchiveBot |fix-attempted=yes }}. Foam Cast,{{Citation | title = American Foam Cast | url = http://www.americanfoamcast.com/home.asp | access-date = 2009-03-29}}. Replicast,{{Citation | title = Replicast Process (CS) | url = http://www.engnetglobal.com/tips/glossary.aspx?word=Replicast+Process+(CS) | access-date = 2009-03-29}}. Policast. and Lost Foam Sintered Shell (LFSS){{Cite web|url=http://www.metaforecastings.com/|title=Metafore Castings Private Limited - Pioneers in Stainless Steel, Alloy Steel and SGI Castings through Lost Foam Sintered Shell Process in India|website=www.metaforecastings.com|access-date=2018-12-05}}
History
The first patent for an evaporative-pattern casting process was filed in April 1956, by Harold F. Shroyer. He patented the use of foam patterns embedded in traditional green sand for metal casting. In his patent, a pattern was machined from a block of expanded polystyrene (EPS), and supported by bonded sand during pouring. This process is now known as the full mold process.{{Citation | last = Donahue | first = Raymond | first2 = Kevin | last2 = Anderson | title = Lost Foam Casting | publisher = ASM International | url = http://www.asminternational.org/portal/site/www/AsmStore/ProductDetails/?vgnextoid=ac4266ecb9f1f110VgnVCM100000621e010aRCRD | access-date = 2010-04-06 | postscript =.}}{{US Patent|2830343}}
In 1964, M.C. Flemmings used unbonded sand for the process. The first North American foundry to use evaporative-pattern casting was the Robinson Foundry at Alexander City, Alabama. General Motors' first product using these processes was the 4.3 L, V-6 diesel cylinder head, which were made in 1981 at Massena, New York.{{Citation | last = Biswanath | first = Mondal | title = Proceedings of the National Conference on Investment Casting: NCIC 2003 | publisher = Allied Publishers | year = 2004 | url = https://books.google.com/books?id=PRYPsBr7cqgC&pg=PA169 | isbn = 978-81-7764-659-7 }}
A study found in 1997 that evaporative-pattern casting processes accounted for approximately 140,000 tons of aluminium casting in the United States. The same survey forecast that evaporative-pattern casting processes would account for 29% of the aluminium, and 14% of the ferrous casting markets by 2010.{{Citation | last = Bodine | first = Jack R. | title = From a monument to the Vega: the journey of the aluminum casting industry | journal = Modern Casting | page = 13 | date = 1999-05-01 | url = http://www.allbusiness.com/manufacturing/fabricated-metal-product-manufacturing/266328-1.html}}.{{Citation | title = Success through partnership: lost foam | date = September 1998 | url = http://www1.eere.energy.gov/industry/metalcasting/pdfs/mciof.pdf | access-date = 2009-03-30}}.
References
{{Reflist}}
=Bibliography=
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- {{Citation | last = Degarmo | first = E. Paul | last2 = Black | first2 = J T. | last3 = Kohser | first3 = Ronald A. | title = Materials and Processes in Manufacturing | publisher = Wiley | year = 2003 | edition = 9th | isbn = 0-471-65653-4}}.
- {{Citation | last = Totten | first = George E. | last2 = Funatani | first2 = Kiyoshi | last3 = Xie | first3 = Lin | title = Handbook of metallurgical process design | publisher = CRC Press | year = 2004 | edition = illustrated | url = https://books.google.com/books?id=3zjfgq8pUvcC | isbn = 978-0-8247-4106-8}}.
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