Real time observation of binder jetting printing process using high-speed X-ray imaging

Niranjan D Parab,Ross W Cunningham,Anthony D Rollett,Tao Sun,Kamel Fezzaa,John E Barnes,Cang Zhao

doi:10.1038/s41598-019-38862-7

Niranjan D Parab, Ross W Cunningham + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-38862-7

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Abstract

A high-speed synchrotron X-ray imaging technique was used to investigate the binder jetting additive manufacturing (AM) process. A commercial binder jetting printer with droplet-on-demand ink-jet print-head was used to print single lines on powder beds. The printing process was recorded in real time using high-speed X-ray imaging. The ink-jet droplets showed distinct elongated shape with spherical head, long tail, and three to five trailing satellite droplets. Significant drift was observed between the impact points of main droplet and satellite droplets. The impact of the droplet on the powder bed caused movement and ejection of the powder particles. The depth of disturbance in the powder bed from movement and ejection was defined as interaction depth, which is found to be dependent on the size, shape, and material of the powder particles. For smaller powder particles (diameter less than 10 μm), three consecutive binder droplets were observed to coalesce to form large agglomerates. The observations reported here will facilitate the understanding of underlying physics that govern the binder jetting processes, which will then help in improving the quality of parts manufactured using this AM process.

Highlights

Additive Manufacturing (AM) is a disruptive technology that adds material in a layer-wise fashion to build complex parts
The high-speed synchrotron X-ray imaging experiments were performed at beamline 32-ID-B, Advanced Photon Source (APS), Argonne National Laboratory
Some important physical processes involved in binder jetting additive manufacturing (AM) were investigated in-situ using high-speed synchrotron X-ray imaging

Summary

Introduction

Additive Manufacturing (AM) is a disruptive technology that adds material in a layer-wise fashion to build complex parts. Binder jetting AM uses iterative ink-jet printing of binder material on powder beds to create parts[4,5]. A layer of powder is spread to a desired thickness and the binder is precisely deposited on the powder bed, applying adherent liquid that binds the powder particles together locally. Several physical phenomena govern the quality of binder jetted parts, including droplet formation in nozzles, powder flow and packing in powder bed, powder-binder interactions, binder curing, and thermal sintering of the green part[32]. Since the lines printed using DoD print-heads have been found to reside below the surface of the powder bed[22], it is imperative to obtain sub-surface information to fully understand the physical processes involved in binder jetting. The quantitative experimental data provides crucial insights into the binder jetting processes which will help reduce the defects and improve the quality of binder jetted parts, and help develop and validate numerical models

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