Thermo-Fluidics of Solid Ink-Solid Surface Interaction Sunny Ri Li and Nasser Ashgriz Department of Mechanical and Industrial Engineering University of Toronto

Experimental setup

Major Components High-speed Video Camera LabView, PXI board and SCXI Signal Conditioner Substrate with heater mounted on a linear-movement and tilt and rotation stage Lighting Sources

Setup for impaction The substrate surface is 5 mm away from the print head..

Droplet Impaction on 23 o C Substrate Diameter: 269 microns (100 droplets) Droplet speed: 1.59m/s Diameter: 178 microns (50 droplets) Droplet speed: 1.59m/s Height: 28.5 microns Width: 51.6microns (1 droplet) Droplet speed: 0.65~1 m/s Contact angle: 70 deg. Height: 46.8 microns Width: microns (10 droplets) Droplet speed: 0.65~1 m/s Contact angle: 70 deg.

Arrest of advancing contact line Time: t (1 droplet) Time: t+3/4000 sec. (2 droplets) Time: t+6/4000 sec. (3 droplets) Time: t+15/4000 sec. (6 droplets) Time: t+29/4000 sec. (10 droplets) Time: t+117/4000 sec. (40 droplets)

Droplet Impaction on Heated Substrate Temperature of the substrate: 60 o C (20 droplets) Contact angle: 60 deg. Temperature of the substrate: 78 o C; 1 droplet Contact angle: 48 deg. Temperature of the substrate: 90 o C (10 droplets) Contact angle: 25 deg. Time: t Time: t+1/8000 sec. Time: t+2/8000 sec.

Impaction of large wax drop Drop diameter: 2.89mm; Velocity: 0.92m/s; We=70.4; Temperature of substrate: 40 o C Temperature of drop: 85 o C Drop diameter: 1.98mm; Velocity: 0.5m/s; We=14.3; Temperature of substrate: 40 o C Temperature of drop: 85 o C Wax drop impacting on an aluminum surface Wax drop impacting on another solidified drop

Setup for Visualizing Ink Ejection