  Metal-based additive manufacturing (AM) represents a paradigm change in
engineering and production methods across multiple industries and sectors. AM
methods enable mass reduction and performance optimisation well beyond that
achievable via conventional manufacturing, thereby impacting significantly on
aerospace and space technologies. Technologies relying on high and ultra-high
vacuum (UHV), such as x-ray photo-electron spectroscopy, photo-sensors, cameras
and cryostats, could also benefit greatly from AM. Despite recent advances in
AM processing of metals, additively manufactured UHV chambers have so far not
been achieved. Reducing the mass of UHV equipment is particularly critical for
the development of portable cold atom systems, which are expected to underpin
the next generation of sensing and timekeeping technologies and to allow novel
space-based sensors for fundamental research. We demonstrate here an additively
manufactured UHV chamber reaching a pressure below $10^{-10}$ mbar, enabling a
cloud of cold $^{85}$Rb atoms to be trapped - the starting point for many
precision timekeeping and sensing devices. The chamber is manufactured from
aluminium alloy AlSi10Mg by laser powder bed fusion and has a mass of less than
a third of a commercially-available equivalent. Outgassing analysis based on
mass spectrometry was performed and it was demonstrated that even without
active pumping the system remains in the $10^{-9}$ mbar regime for up to 48
hours.
