Laser jetting of femto-liter metal droplets for high resolution 3D printed structures.

M Zenou,A Sa’Ar,Z Kotler

doi:10.1038/srep17265

Abstract

Laser induced forward transfer (LIFT) is employed in a special, high accuracy jetting regime, by adequately matching the sub-nanosecond pulse duration to the metal donor layer thickness. Under such conditions, an effective solid nozzle is formed, providing stability and directionality to the femto-liter droplets which are printed from a large gap in excess of 400 μm. We illustrate the wide applicability of this method by printing several 3D metal objects. First, very high aspect ratio (A/R > 20), micron scale, copper pillars in various configuration, upright and arbitrarily bent, then a micron scale 3D object composed of gold and copper. Such a digital printing method could serve the generation of complex, multi-material, micron-scale, 3D materials and novel structures.

Highlights

Digital printing of metals is probably the single most important element missing from functional 3D printing, a technology that today still relies almost entirely on polymer materials. 3D structures made up of polymers usually lack the required mechanical, electrical and thermal properties for functional structures and devices
A laser pulse focused on the interface between the metal layer and the substrate induces local thermal heating followed by a phase change and high local pressure which drives the jetting of the print material
Droplets, which emerge from such a molten metal layer, typically have limited directionality and as a result, the print accuracy is rather low unless the donor is brought into very close proximity, typically a few tens of microns, to the acceptor substrate[16,17,18,19,20,21,22,23,24,25]

Summary

Introduction

Digital printing of metals is probably the single most important element missing from functional 3D printing, a technology that today still relies almost entirely on polymer materials. 3D structures made up of polymers usually lack the required mechanical, electrical and thermal properties for functional structures and devices. A laser pulse focused on the interface between the metal layer and the substrate induces local thermal heating followed by a phase change and high local pressure which drives the jetting of the print material.

Results

Conclusion