details DESIGN


Feature-Rich Casting Made Possible With Lost Foam


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


Cast Component: Timing gear cover for agriculture equipment.


Casting Process: Lost foam casting.


Material: Gray iron class 30. Weight: 97.1 lbs. Dimensions: 22 x 22 x 7 in.


I


n order to incorporate all the desired components and features into a part for a new engine series for reduced emissions, an agriculture equipment manufacturer partnered with Grede Holdings LLC’s lost foam casting company in Columbiana, Ga. A lost foam-based design allowed lower cost by eliminating bolt-on components and reduced weight by signifi cant


reduction in draft angles. T e overall one-piece design incorporated a water pump volute, EGR passage and coolant return passage, idler pulley mounting pedestal and alternator mounting bracket, trust washer face and various as-cast passages and openings. Cast iron off ered signifi cant noise reduction, corrosion resistance and bolt torque retention compared to the alternative aluminum design.


Generous fi llet and radii aid fi lling and solidifi cation.


• Smooth transitions by generous fi llet and radii are desired for less turbulent liquid metal fl ow into the cavity and facilitate a stronger foam pattern.


Lost foam provides the ability to make as-cast intricate cored holes and passages with tight dimensional tolerances, (e.g. true positioning).


• Conventional molding processes create hollow features by placing a core into the mold cavity, thus aff ecting dimensional tolerances and reproducibility. In lost foam, features such as holes, passages and volute areas are made without cores (as-cast), off ering true positioning.


• Near-net-shape features eliminate machining and the need for extra stock.


24 | METAL CASTING DESIGN & PURCHASING | Nov/Dec 2011


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