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The printing head-to-target distance is known to affect printing quality in DoD printing systems .
Quantifying this effect is important for identifying the operational window in in situ printing
applications, including the maximum distance limit to maintain a desired level of printing quality.

To address this for the mobile LIST printing head, we conducted printing experiments using a
model ink (viscosity: 18 cP), varying the distance between the printing head and the target substrate

(Figure 2a). Splatter coverage was used as the primary metric to quantify print quality.

Figure 2. a) Schematic overview of the approach used to investigate the effect of varying the

printing head-to-target distance on print quality. b) Optical microscope images of model ink arrays
printed at different printing head-to-target distance. The effect of varying the printing head-to-

target distance on c) splatter coverage, d) drop placement error, e) drop circularity, and f) drop
area.

Figure 2b shows optical microscopy images of arrays of model ink droplets printed at constant

energy per pulse (230 µJ, corresponding to 1.15-times the printing threshold energy) across
different printing head-to-target distances. The maximum range at which splatter coverage

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