  Informing Additive Manufacturing (AM) technology adoption decisions, this
paper investigates the relationship between build volume capacity utilisation
and efficient technology operation in an inter-process comparison of the costs
of manufacturing a complex component used in the packaging industry.
Confronting the reported costs of a conventional machining and welding pathway
with an estimator of the costs incurred through an AM route utilising Direct
Metal Laser Sintering (DMLS), we weave together four aspects: optimised
capacity utilisation, ancillary process steps, the effect of build failure, and
design adaptation. Recognising that AM users can fill unused machine capacity
with other, potentially unrelated, geometries, we posit a characteristic of
'fungible' build capacity. This aspect is integrated in the cost estimation
framework through computational build volume packing, drawing on a basket of
sample geometries. We show that the unit cost in mixed builds at full capacity
is lower than in builds limited to a single type of geometry; in our study this
results in a mean unit cost overstatement of 157%. The estimated manufacturing
costs savings from AM adoption range from 36% to 46%. Additionally, we indicate
that operating cost savings resulting from design adaptation are likely to far
outweigh the manufacturing cost advantage.
