  We investigate the physical conditions where 44Ti and 56Ni are created in
core-collapse supernovae. In this preliminary work we use a series of
post-processing network calculations with parametrized expansion profiles that
are representative of the wide range of temperatures, densities and
electron-to-baryon ratios found in 3D supernova simulations. Critical flows
that affect the final yields of 44Ti and 56Ni are assessed.
