Investigation of Nozzle Height Control to Improve Dispenser Printing of E-Textiles

Abstract

Dispenser printing is a versatile way of manufacturing prototype and bespoke e-textiles that uses a robotically actuated nozzle to dispense pastes. Investigation of printing on a flat substrate, however, revealed that the nozzle must be kept between 50 and 200 µm above the material’s surface in order to print effectively. In order to maintain this clearance when printing on uneven materials, the surface topography of the substrate must be measured and compensated for. However, the accuracy of the laser displacement meter used here was reduced when measuring the translucent interface layer necessary when printing on textiles. Adding various concentrations of dye to the interface was explored. A single layer of interface with 20 mg of dye added per gram showed significantly improved results with an average error of 146 µm compared to the 550 µm for the clear interface. Crucially, the standard deviation in the error was only 31 µm, down from 101 µm, meaning that an offset could be applied to get measurements that would keep the nozzle’s clearance within the necessary 150 µm range.