The PoDFA technique consists of filtering, under controlled conditions, a predetermined quantity of liquid aluminum through a very fine porosity filter disc. Inclusions of the melt are concentrated at the filter surface by a factor of 10,000.

Developed by Alcan and commercialized by ABB, PoDFA is a method of metal cleanliness evaluation that provides both qualitative information on the nature of inclusions and quantitative information on the inclusion concentration.

This technology is ideal for process control and development as well as for product certification. It can help assess the effect of various operating practices on metal cleanliness.