In recent years there has been a rapid expansion in the number
and quality of commercially available, affordable, fused deposition
modelling (FDM) 3D-printers. These FDM 3D-printers allow end
users to design, test and construct bespoke 3D-fabricated plastic
prototypes targeted to their own individual applications [1]. Researchers
in the chemical and biomedical sciences have made
bespoke integrated reactionware [2e7], DNA adhesives [8], inserts
for cuvettes [9] or X-ray absorption spectroscopy [10] that enable
spectroelectrochemistry to be performed, surgical models and
synthetic organs [11] and microfluidic pumps [12]. However, whilst
there are a significant number of recent research success stories
demonstrating the potential applications of 3D-printers, a number
of key challenges remain. In particular the additive manufacturing
process of FDM printing has a tendency to create small gaps between
successive extruded layers, meaning 3D-prints are not always
air or watertight. This is a particular challenge for FDM 3Dprinting
in milli or microfluidic applications where the pressure in
the device is increased. Strategies for solving this leakage problem
differ, one approach is to construct devices with increased wall
thicknesses, typically 4 mm [3], although this does impose a lower
limit on the size of device that can be constructed. Alternatively,
recent work [13] has shown that many of these printing