Drop-on-demand deposition of superheated metal droplets for selective infiltration manufacturing

The deposition of metal droplets is of great engineering interest because of its practical applications to such various fields as spray forming, surface treatments, and solid freeform fabrication (SFF), etc. The objective of this work is to develop a new drop-on-demand generator of superheated metal droplets that is suitable for the selective infiltration manufacturing (SIM), a new SFF process for the direct fabrication of metal parts. The developed generator comprises a solenoid vibrator, a micro-drilled 130 μm diameter nozzle, an impulse-transmitting rod, and a tubular heating element. A parametric study showed that the diameter of droplets was 301 ± 10 μm when the superheating temperature of Sn-37Pb wt% was set at 260 °C, 299 ± 12 μm at 290 °C, and 301 ± 12 μm at 320 °C. Experiments showed that the developed generator is able to deposit superheated metal droplets according to the frequency of the vibrator.