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details DESIGN


Lost Foam Enables Key Features in EGR Valve Body


JITEN SHAH, PRODUCT DEVELOPMENT & ANALYSIS, NAPERVILLE, ILLINOIS CASTING PROFILE


Cast Component: EGR valve body for a heavy truck diesel engine.


Casting Process: Lost foam.


Material: High silicon molybdenum iron, grade 3. Weight: 12.1 lbs. Dimensions: 7 x 8 x 5 in.


designing the part. Lost foam off ers near-net-shape benefi ts due to its capability to produce complex castings with excellent dimensional tolerance and surface fi nish. T is process is suitable for medium- to high-volume productions, mainly due to the tooling’s higher cost and longer lead time. However, with developing rapid prototyp- ing techniques, lost foam is expanding into low volume production applications. T e EGR valve body with water cooling jacket for electronics combines multiple


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parts with reduced machining operations and machining stock. T e as-cast water jacket allowed improved cooling and protection of the temperature-sensitive valve control electronics. T e part was designed to utilize a stainless steel insert inside the casting to act as a bushing for increased wear resistance for mating components. Superior internal surface fi nish improved fl uid fl ow for better heat transfer.


rede’s iron casting facility in Columbiana, Ala., utilized the lost foam process to reduce the weight and cost of an EGR valve body for a heavy truck diesel engine. With lost foam, design engineers have fl exibility in designing and placing features, as they don’t have to consider parting plane, draft, cored holes or appendages when


Zero or negative draft features are possible with lost foam.


• T e overall impact of reduced draft , combined with generous fi llet, radii and transitions, is reduced weight and cost, and streamlined water passages.


Casting-in a stainless steel insert enhances the wear performance of mating parts.


• When the lost foam pattern pieces are assembled together, it is possible to incorporate cast-in bimetallic inserts. T is capability off ers fl exibility with part consolidation and improved performance.


18 | METAL CASTING DESIGN & PURCHASING | Nov/Dec 2012


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