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Improving accuracy of powder‐based SFF processes by metal deposition from a nanoparticle dispersion

Nathan B. Crane (Sandia National Laboratories, Albuquerque, New Mexico, USA)
J. Wilkes (Department of Mechanical Engineering, MIT, Cambridge, Massachusetts, USA)
E. Sachs (Department of Mechanical Engineering, MIT, Cambridge, Massachusetts, USA)
Samuel M. Allen (Department of Materials Science and Engineering, MIT, Cambridge, Massachusetts, USA)

Rapid Prototyping Journal

ISSN: 1355-2546

Article publication date: 1 October 2006

1597

Abstract

Purpose

Solid freeform fabrication processes such as three‐dimensional printing (3DP) and selective laser sintering (SLS) produce porous parts. Metal parts produced by these processes must be densified by sintering or infiltration to achieve maximum material performance. New steel infiltration methods can produce parts of standard alloy compositions with properties comparable to wrought materials. However, the infiltration process introduces dimensional errors due to both shrinkage and creep — particularly at the high temperatures required for steel infiltration. Aims to develop post‐processing method to reduce creep and shrinkage of porous metal skeletons.

Design/methodology/approach

The proposed process treats porous metal parts with a nanoparticle suspension that strengthens the bonds between particles to reduce creep and sintering shrinkage during infiltration. The process is tested by comparing the deflection and shrinkage of treated and untreated cantilevers heated to infiltration temperatures. The method is demonstrated with an iron nanoparticles suspension applied to parts made of 410 SS powder.

Findings

This process reduced creep by up to 95 percent and shrinkage by 50 percent. The best results were obtained using multiple applications of the nanoparticles dried under a magnetic field. Carbon deposited with the iron is shown to provide substantial benefit, but the iron is critical to establish strong bonds at low temperatures for minimal creep.

Research limitations/implications

This work shows that dimensional stability of porous metal skeletons during infiltration processes can be significantly improved by treatment with nanoparticles. The increased dimensional stability afforded by this technique can combine the excellent properties of homogenous infiltration with substantially improved part accuracy and open up new applications for this manufacturing technology.

Originality/value

The work shows how solid freeform fabrication processes can be improved.

Keywords

Citation

Crane, N.B., Wilkes, J., Sachs, E. and Allen, S.M. (2006), "Improving accuracy of powder‐based SFF processes by metal deposition from a nanoparticle dispersion", Rapid Prototyping Journal, Vol. 12 No. 5, pp. 266-274. https://doi.org/10.1108/13552540610707022

Publisher

:

Emerald Group Publishing Limited

Copyright © 2006, Emerald Group Publishing Limited

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