Casting conversion of railroad part puts inventory on fast track.

Many casting customers understand that multiple-piece fabrications often bring along the expense of extra machining, assembly, transportation time and scheduling changes, along with extra items to keep track of for inventory. And while design engineers know that castings often reduce or eliminate these added steps and costs, offering prototyping services to test preliminary designs allows metalcasters to physically prove the success of a new design.

Olson Aluminum Castings, Rockford, Ill., produced prototypes castings to prove out a casting conversion design for a brake adjustor component for the railroad industry, which in the end saved the customer considerable time and money.

Originally produced as a three-piece machined fabrication, the component consisted of a machined section of steel tubing, a machined forging and a turned steel ring. Additional processing included friction welding, finish machining and plating for corrosion resistance. Olson Aluminum knew that converting the three-piece part to a single piece casting would reduce the cost of these finishing operations and ease the inventory challenges of juggling multiple components. However, several criteria had to be met in order to make the conversion. Olson Aluminum, along with the customer staff, engineered and produced a prototype tool to prove out both the customer's design and the metalcasting process.

First, the adjuster would need to withstand a 10,000-lb. linear pull test with special attention given to minimum wall thickness along with the two narrow side walls located in the area of the rectangular window. The ability to consistently produce castings with a tight grain structure free from porosity and shrinkage was critical to achieving this structural specification. Additionally, an O-ring surface required above the window area needed to be free from any porous condition that would be exposed during machining and plating. These requirements fit Olson Aluminum's core competency.

Second, the surface areas of the brake adjuster would need to exhibit increased wear characteristics and remain free from corrosion in an extremely harsh environment. Hard coat anodizing was proposed and tested on the prototypes, which were then put through rigorous testing. Results from the tests demonstrated their ability to meet and exceed the desired engineering requirements.

Final design advantages for a casting were those typically associated with a conversion from a multiple-piece fabrication to a single-piece casting and included reduced cost, weight, lead time and inventory reduction in addition to simplified scheduling.

Visit www.olsonalum.com for more information.