Molding Methods & Materials.

The presentations of the AFS Molding Methods & Materials Div. aimed to help metalcasters produce better castings through a better understanding of sand and binders.

In their presentation, "Versatile Core Sand Test Method," (04-108) S.G. Baker and J.M. Werling, Indianapolis Casting Corp., described a testing method that provides information on not only core strength, but shrinkage, sand flowability and deflection.

The authors explained that all of the information can be derived without changing the corebox, which allows one mixture of sand to be evaluated for a number of features, eliminating the variable of batch-to-batch variation. This information can be used to control or benchmark current processes, but also can be used to evaluate other resin systems, sands or sand mixes.

The test was done with a phenolic urethane coldbox resin, but the techniques are applicable to other binder systems as well.

V.S. LaFay and S.L. Neltner, Hill & Griffith Co., explored the possibility of producing green sand molds with seacoal in their presentation, "Green Sand Without Seacoal," (04-111).

The authors reviewed the casting applications of green sand molding requirements without seacoal with the theoretical and practical application of replacement materials and their benefits. The applications include the review of expansion characteristics, benefits to the molding sand and emission characteristics.

The authors explained that some within the industry would like to eliminate or reduce seacoal due to the emission characteristics. But to do that, changes in the green sand molding process are required to accommodate the molding sand characteristics when seacoal is replaced with supplements, reduced or eliminated.