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CASTING INNOVATIONS


shops,” Ramrattan said. “Tis could be a rapid casting technology. We were meet- ing and exceeding the traditional build speeds that 3-D printing would allow.


Tey can cure thousandths of an inch at one time and a mold can take 48 hours. Our cure layers are a little larger than a quarter of an inch, about 8 mm, and we can produce molds in a few hours. We have an advantage in throughput.” Te molds begin as a digital model that’s sectioned into layers so a CNC code can be pro- duced for each layer. Sand is cured in a working enve- lope of a three-axis CNC mill, and the part cavity for that layer is machined. Te completed layer then is filled with uncured sand to preserve the cavity. A new layer of coated sand is placed in the apparatus and cured, and the CNC mill again machines the cav- ity. Tis process repeats until the entire mold is built layer by layer. Te uncured sand is removed, and metal is cast into the mold. Te total time from digital


model to final casting can be less than six hours. While early results are


Ramrattan continues to work on the process with help from two WMU gradu- ate assistants.


encouraging, the process faces significant challenges before it can be consid- ered commercially viable for metalcasting facilities. Surface finish must be improved, and Ramrat- tan’s team is still in search of sand coatings. Hemant Bohra and Michael Kon- kel, two WMU graduate students, are investigating coatings, as well as machin-


ing and automation improvements. “By no means is the process com-


mercially ready, but the proof of con- cept is in place,” Ramrattan said. “If we can improve the surface finish and get the right types of coatings, I believe it will be something viable.”


Tis article is based on a paper (14-062- 2) that will be presented at the 2014 AFS Metalcasting Congress in Schaumburg, Ill.


March 2014 MODERN CASTING | 83


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