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savings are likely to be off set by increased fi nishing cost or perfor- mance problems. T e function of cast parts may


require diff erent quality levels. Commercial castings normally are inspected only for surface defects. However, for critical applications, visual inspection is not enough.


T ey may require X-ray and fl uores- cent penetrant inspection for fl aws in the part. To obtain the right product at the right price, request for quotes should list all the requirements as thoroughly as possible. Good quality begins with good


design for performance and manufac- turability. In the end, the metalcasting


FROM THE METALCASTER’S PERSPECTIVE


Below are two casting cost estimating forms for typical high production metalcasting facilities, one for aluminum and another for ductile iron. Just as a buyer should be well informed about what factors impact the fi nal cost, the metalcasting facility will monitor all the variables involved in delivering quality castings. Costs will break down into three main catego-


High Production Aluminum Metal/Melting Costs


Metal (based on casting weight) Melting (based on pour weight)


Molding/Pouring/Cleaning Costs Automatic molding Pouring


Cleaning (shotblasting)


Coremaking, Dipping, Assembly Costs Coremaking


Casting Finishing Costs Trim pressing Belt grinding


100% inspection/gaging Painting


Miscellaneous Operating Costs


Heat treating (based on casting weight)


Container (based on pieces/container and casting weight)


Shipping Set-up charge Other miscellaneous costs


Selling, General & Administrative Expense Total Unit Cost


0.00%


0.24% 0.05%


1.26%


96.50% 3.50%


100.00%


Core A


ries: materials, direct labor and expenses. Materi- als may be subdivided into raw materials (primary metal and alloying constituents) and process mate- rials (coke, sand, molding materials, etc.). Automa- tion has improved productivity in the metalcasting industry, but labor remains a high percentage of costs. 


Cost


25.52% 3.40%


0.72% 1.36% 0.09% Cost


24.92%


B 19.64% C


7.67%


1.14% 2.41%


0.00% 2.06%


Casting Finishing Costs Snag Grind Bench grind


100% inspection/gaging Paint


Miscellaneous Operating Costs


Heat treating (based on casting weight)


Container (based on pieces/container and casting weight)


Shipping Set-up charge Other miscellaneous costs


Selling, General & Administrative Expense Total Unit Cost


0.00%


0.61% 0.14%


0.00%


96.50% 3.50%


100.00%


High Production Ductile Iron Metal/Melting Costs


Metal (based on casting weight) Melting (based on pour weight)


Molding/Pouring/Cleaning Costs Automatic molding Pouring


Cleaning (shotblasting)


Coremaking, Dipping, Assembly Costs Coremaking


Core A


facility is responsible for turning that design into a quality casting, which requires process control throughout the steps of production.


6


Order Quantity Order quantity is an impor-


tant factor in selecting appro- priate tooling. Production effi ciency is


Cost


9.33% 16.66%


4.06% 6.66% 0.23% Cost


4.52%


B 3.56% C


1.39% 7.95%


36.36% 0.00% 5.03%


30 | METAL CASTING DESIGN & PURCHASING | Jul/Aug 2014


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