Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Powder characterization and part density for powder bed fusion of 17-4 PH stainless steel

Powder characterization and part density for powder bed fusion of 17-4 PH stainless steel Characteristics of the metal powder are a key factor in the success of powder bed fusion (PBF) additive manufacturing. Powders for PBF from different manufacturers may have a different particle size and/or bulk packing and flow behavior. Powder properties change as the powder is reused for multiple builds. This study seeks to measure the variability of commercial 17-4 PH stainless steel powders to determine the effect of powder variability on part density and demonstrate characterization methods that ensure part quality.Design/methodology/approachCommercial atomized metal powders from four different vendors were produced with two different atomizing gases (N2 and argon). Powder was characterized in both new and extensively reused conditions. All powders were characterized for flow and packing behavior, particle size and internal porosity. Coupons were manufactured using the laser PBF process with optimized scan strategy and exposure parameters. The quality of fabricated parts was measured using bulk density measurement.FindingsDespite differences in powder flowability and particle size, fully dense parts (>99 per cent) were produced using all powders, except one. Residual porosity in these parts appeared to result from gas trapped in the powder particles. The powder with extensive reuse (400+ h in machine fabrication environment) exhibited reduced flowability and increased fraction of fine particles, but still produced full density parts.Originality/valueThis study demonstrates that full density parts can be fabricated using powders with a range of flowability and packing behavior. This suggests that a single flowability measurement may be sufficient for quality assurance in a production environment. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Rapid Prototyping Journal Emerald Publishing

Powder characterization and part density for powder bed fusion of 17-4 PH stainless steel

Loading next page...
 
/lp/emerald-publishing/powder-characterization-and-part-density-for-powder-bed-fusion-of-17-4-ZTTtj0vWyI
Publisher
Emerald Publishing
Copyright
© Emerald Publishing Limited
ISSN
1355-2546
eISSN
1355-2546
DOI
10.1108/rpj-01-2020-0023
Publisher site
See Article on Publisher Site

Abstract

Characteristics of the metal powder are a key factor in the success of powder bed fusion (PBF) additive manufacturing. Powders for PBF from different manufacturers may have a different particle size and/or bulk packing and flow behavior. Powder properties change as the powder is reused for multiple builds. This study seeks to measure the variability of commercial 17-4 PH stainless steel powders to determine the effect of powder variability on part density and demonstrate characterization methods that ensure part quality.Design/methodology/approachCommercial atomized metal powders from four different vendors were produced with two different atomizing gases (N2 and argon). Powder was characterized in both new and extensively reused conditions. All powders were characterized for flow and packing behavior, particle size and internal porosity. Coupons were manufactured using the laser PBF process with optimized scan strategy and exposure parameters. The quality of fabricated parts was measured using bulk density measurement.FindingsDespite differences in powder flowability and particle size, fully dense parts (>99 per cent) were produced using all powders, except one. Residual porosity in these parts appeared to result from gas trapped in the powder particles. The powder with extensive reuse (400+ h in machine fabrication environment) exhibited reduced flowability and increased fraction of fine particles, but still produced full density parts.Originality/valueThis study demonstrates that full density parts can be fabricated using powders with a range of flowability and packing behavior. This suggests that a single flowability measurement may be sufficient for quality assurance in a production environment.

Journal

Rapid Prototyping JournalEmerald Publishing

Published: Dec 7, 2020

Keywords: Additive manufacturing; Selective laser melting; 17-4 PH stainless steel; Powder bed fusion; Powder characterization

References