Released on September 12, 2008
 
AlumAlloy Co. Inc., Ontario, California, recently completed a contract for more than 300 bunker buster bomb nose cones for the U.S. Navy.

The Navy designed the new bomb nose cone castings, which require Grade C radiography testing, to minimize machining costs. The castings were required to meet inside and outside contour tolerances of +/-0.026 in. The tolerances were verified with a coordinate measuring machine.

“At first we were hand-grinding the outer surface of the castings [to remove the ingates and risers], and it was time consuming,” said Steve Isham, the company’s general manager. “Later, machine stock was added to the pattern contour, and the castings were machined in-house to the final contour.”

AlumAlloy is a sand casting facility that serves the aerospace and automotive markets, in addition to its defense customers.

“The [nose cones’] symmetrical configuration lent itself to a vertical pour,” said David Howell, president and senior casting engineer for AlumAlloy. “We used resin-bonded sand and our proprietary technique for a modulated vertical pour. This technique effectively eliminated entrained bubbles and all other defects.”