With continuing pressure of global competition especially from low labor cost countries, the US investment casting industry must continue to reduce costs with technical supremacy. Enhancing foundry competitiveness through reduction of inclusion scrap and minimizing the inclusion related rework is a challenging but achievable goal. The technical paper discusses the sources and control of inclusions in wax, shell, melting and pouring process steps. Steps in controlling inclusion defects discussed in the paper include: Tracking and characterizing inclusion defects to identify properties and trends, Correlating inclusion properties and trends to process, environment, materials and equipment properties and controls, Implementing changes that have the strongest correlation to the occurrence of inclusions, Tracking and characterizing the impact of the changes to verify a correlation, Standardizing changes that have a verified impact and Starting the next incremental improvement loop. Examples of inclusion control efforts involving implementing best practice, processes, materials, equipment and controls are discussed.
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