AnExampleofMoldTolerancesasfeaturedinMachine.PDFVIP

Printed in U.S.A., Copyright © 200 1 . Penton Media, Inc. All rights reserved. Machine De- sign (ISSN 0024-9114) is published semi- monthly by Penton Media, Inc., 1300 E. 9th St., Cleveland, OH 44114- 1503. Copies not qualified for domestic requester circulation: one year, $105; two years, $165. Permission to photocopy is granted for users registered with the Copyright Clearance Center (CCC) Inc. to photocopy any article, with the exception of those for which separate owner- ship is indicated on the first page of the arti- cle, provided that the base fee of $1.25 per copy of the article, plus $.60 per page is paid to CCC, 222 Rosewood Dr., Danvers, MA 01923 (Code No. 0024-9114/0 1 $1.25 + .60). Permission to reprint: Barbara LoSchi- avo; (216-696-7000, ext. 9607) Machine Design, 1300 E. 9th St., Cleveland, OH 44114- 1503 216-696-7000. Materials engineering Edited by Jean Hoffman A better way to cast aluminum Gravity casting aluminum in permanent molds beats conventional sand and pressure die casting. Arun Gupta Gupta Permold Corp. Pittsburgh, Pa. The mold for this 17-lb, 48-in.-diameter fan was reverse engineered from a sand casting. The fan used in an agricultural application is cast in one piece. The high oday, gravity-fed permanent metal molds can repeatability of the permanent-mold casting process produce near-net-shape parts from a variety of helps minimizes secondary machining operations and aluminum alloys. But it’s up to the designer to spin balancing processes. Tmakes sure it’s both possible and profitable to use permanent molds to produce the part. Knowing the limits of this casting process can help designers create Casting compari