Precision machining of exotic geometry prototype propellers; NMRS project for Lockheed Marine Systems.
These exotic counter-rotating propeller sets were machined from 6061-T6 plate aluminum which was UT inspected prior to machining. Each billet started out approximately 17 inches in diameter and 7 inches thick, weighing about 135 lbs. The finished propellers weighed about 5 lbs. These parts required meticulous hand finishing to a virtual mirror finish, and then a hard anodize coating for corrosion resistance.
For these parts, the customer supplied us with a fairly crude wire frame IGES file defining section contours on the blade surfaces. They also provided a drawing that detailed the hub and keyways. We synthesized all of the complex surfaces and toolpaths in house.