Increasingly, Additive Manufacturing is seen as a route to manufacturing porous structures with targeted and tailored sound absorbing properties. Nevertheless, several problems have been encountered when using 3D printing for this purpose. This provides the motivation for the workshop which will review and discuss examples and experiences in 3D printing of porous sound absorbers, fundamental definitions of microstructural parameters, analytical and numerical models for acoustical properties, designs based on enhancing tortuosity and compressibility and multi-functional possibilities. The workshop provides an opportunity to discuss the way forward and the potential for joint funding proposals. There are six invited presentations, but the speakers are asked to confine their presentations to 20 minutes to leave time for discussion after their presentation.