Modeling of Generation of Uniform Metal Droplet During Drop-On-Demand Spray Forming

Droplet deposition and solidification is vital to dimensional accuracy and mechanical properties of components prepared by uniform droplet spray (UDS) forming. In this paper, a volume-of-fluid (VOF) based model was developed to study the deposition and solidification processes of a 1 mm Al-4.5%Cu droplet generated by drop-on-demand jetting. The effects of droplet falling velocity (0.6-0.8 m/s), initial temperature (933-973 K), and substrate temperature (300-473 K) were investigated. The results show that the final morphology of the deposited droplet is largely dependent on falling velocity and substrate temperature. The solidified droplet obtained from an UDS experiment validates the numerical simulation.

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Experimental Research of Pneumatic Drop-on-Demand High Temperature Droplet Deposition for Rapid Prototyping

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.419-420.405 ◽

2009 ◽

Vol 419-420 ◽

pp. 405-408 ◽

Cited By ~ 2

Author(s):

Xiang Hui Zeng ◽

Le Hua Qi ◽

Hua Huang ◽

Xiao Shan Jiang ◽

Yuan Xiao

Keyword(s):

Melting Point ◽

Rapid Prototyping ◽

Oxygen Content ◽

Vertical Direction ◽

Metal Droplet ◽

High Melting ◽

Droplet Deposition ◽

High Melting Point ◽

On Demand ◽

Drop On Demand

Generating high-melting-point metals droplet is a bottleneck in the area of droplet-based rapid prototyping. In our research, a pneumatic drop-on-demand (DOD) generator was developed which can spray A2024 alloy successfully, and the maximum ejection temperature can reach to 1200°C. Experiments were conducted to examine the influence of the oxygen content on the metal droplet spray. The uniform A2024 droplet was ejected stably under the condition where the oxygen content was less than 25ppm. As the solenoid valve was opened once with different time span, four cases were observed: droplet stream, three droplets, two droplets and one single droplet. A2024 droplets were deposited continuously on top of each other in vertical direction to form vertical columns, which meant the graphite nozzle can be used in experiment. A simple square tube was produced by regulating the droplet generator, which showed the rapid prototyping by high-melting-point droplet deposition is feasible.

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Numerical Study on a Drop-on-Demand Micro Droplet Print Head

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.217-219.1429 ◽

2012 ◽

Vol 217-219 ◽

pp. 1429-1434

Author(s):

Cheng Jian Zheng ◽

Sheng Dong Gao ◽

Ying Xue Yao

Keyword(s):

Conceptual Design ◽

Piezoelectric Actuator ◽

Numerical Study ◽

Metal Droplet ◽

Axisymmetric Model ◽

Print Head ◽

On Demand ◽

Drop On Demand ◽

Vof Model ◽

Parametric Studies

A conceptual design of a drop-on-demand(DOD) micro metal droplet print head, which is characterized as the non-heat affection of piezoelectric actuator and a desirable controllability on droplet condition, is devised. With a 2D axisymmetric model and a VOF model, the droplet evolution is simulated for understanding the mechanism within. Parametric studies are followed to investigate relationship between droplet condition and print head parameters for realizing accurate control of droplet condition.

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