Continuous deposition of a liquid thread onto a moving substrate. Numerical analysis and comparison with experiments

The printing of a thin line of liquid onto a moving flat solid substrate was studied numerically. For a fixed value of the Capillary number, the window of steady state deposition was explored in terms of the substrate-nozzle gap and flow rate parameter space for two nozzle configurations: a nozzle pointing vertically at the plate and a nozzle slightly tilted towards the substrate motion direction. A lower limit for the flow rate was found, below which no steady state solutions could be obtained. This minimum flow rate increases as the nozzle stand-off and the nozzle tilting do. Solutions near this lower flow rate boundary were stable under a flow rate perturbation. The process was also studied experimentally and the measurements were compared with the corresponding numerical simulations, giving a fairly good agreement, except in the advancing front deposition region.