Characterization of bulk to thin wall mechanical response transition in powder bed AM
Abstract
Purpose
In the development of powder bed additive manufacturing (AM) process parameters, the characterization of mechanical properties is generally performed through relatively large mechanical test samples that represent a bulk response. This provides an accurate representation of mechanical properties for equivalently sized or larger parts. However, as feature size is reduced, mechanical properties transition from a standard bulk response to a thin wall response where lower power border scans and surface roughness have a larger effect.
Design/methodology/approach
For this study, samples of wall thickness varying between 4.0 and 0.25 mm were built in 304L on the selective laser melting (SLM) platform and Ti-6Al-4V on the electron beam melting (EBM) platform. Samples were then mechanically tested, and fractography was performed for analysis.
Findings
This study experimentally identifies the threshold between bulk and thin wall mechanical properties for 304L SS on the SLM platform and Ti-6Al-4V on the EBM platform. A possible method for improving those properties and shifting the transition from bulk to thin wall response to smaller wall thicknesses by manipulation of scan pattern was investigated.
Originality/value
This study is a novel investigation into the effect of reduced wall thickness on the mechanical properties of a part produced by powder bed AM.
Keywords
Acknowledgements
The authors would like to acknowledge the assistance provided for this research by AM equipment technicians Kevin Davis and Justin Tannehill, as well as microscopists Lauren Elder and Brandon Cox.
All data prepared, analyzed and presented has been developed in a specific context of work and was prepared for internal evaluation and use pursuant to that work authorized under the referenced contract. Reference herein to any specific commercial product, process or service by trade name, trademark, manufacturer or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the US Government, any agency thereof or Honeywell Federal Manufacturing & Technologies, LLC.
This presentation has been authored by Honeywell Federal Manufacturing & Technologies under Contract No. DE-NA0000622 with the USA Department of Energy.
Citation
Brown, B., Everhart, W. and Dinardo, J. (2016), "Characterization of bulk to thin wall mechanical response transition in powder bed AM", Rapid Prototyping Journal, Vol. 22 No. 5, pp. 801-809. https://doi.org/10.1108/RPJ-10-2015-0146
Publisher
:Emerald Group Publishing Limited
Copyright © 2016, Honeywell Federal Manufacturing & Technologies