A new methodology for design of feeding systems for iron castings

摘要

By establishing a method which incorporates correct procedures for design of rigging systems for iron castings, and by using automated software to perform the required calculations, the foundry engineer can quickly and accurately design gating and feeder systems which produce high-quality castings even in the beginning stages of production. The primary goals of the design should be to provide required feed metal during contraction and to control pressure during the expansion phase. The specific elements of this design method are: 1. Calculate the thermal modulus, based on a 3D CAD model of the casting. 2. Calculate the volumetric properties (contraction and expansion) of the cast iron based on chemistry, temperature and modulus. 3. Use the Transfer Modulus to delineate the number, size and location of feeding zones within the casting. 4. Apply only one feeder in each feeding zone. 5. Consider mold dilation as additional feed metal requirement. 6. Size feeders to supply feed metal during the contraction phase. 7. Size the riser neck to freeze when expansion begins. 8. Use hot side risers wherever possible, use sleeves on cold risers if necessary. 9. Size gate contacts to freeze quickly. This methodology will help the foundry to avoid costly trial-and-error procedures and ensure better overall quality for all castings produced.