Preventing Foreign Object Debris (FOD)

As customer demands for increasingly stringent cosmetic and contamination requirements flow into the heat treating industry, the concern for Foreign Object Debris (FOD) has gained significant attention over recent years.

The aerospace industry has long had concerns with FOD that started with airport and flight deck ingestion issues and with mechanic’s tools accountability during aircraft new build, and after maintenance. These issues have since worked their way back into the manufacturing cycle and now many industries have concerns about exactly what gets into the manufacturing stream with their parts and assemblies.  This is of special concern to heat treaters because the high temperatures and somewhat reactive atmospheres employed can create novel problems regarding outright mechanical damage on parts and furnaces to insidious chemical damage on processed surfaces.                          

FOD can enter the heat treating process from many paths.  Suffice to say that the portion of FOD sources within the physical bounds of the heat treat plant and facility should be the first line of defense.  Good housekeeping, clean organized and uncluttered workspaces control of dust and dirt, and persistent furnace hot zone cleaning are all critical to detecting and preventing FOD-related problems.

Shop floor employees and supervisors need to be aware of stray dirt and shop dust, oxidation products from used heat treat fixtures and baskets, leftover packaging entrained in parts (especially those received and processed under bulk loading conditions), and cross-contamination from unidentified tooling like fixture plates and thermocouple dummy blocks.  Even something as commonplace as wind-blown debris through open doors need diligent attention before closing the work into the furnace and committing the product to high temperatures.

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