Characterization of bulk to thin wall mechanical response transition in powder bed AM. Issue 5 (15th August 2016)

• Record Type: Journal Article
• Authors: Brown, Ben; Everhart, Wes; Dinardo, Joe
• Is Part Of: Rapid prototyping journal. Volume 22:Issue 5(2016)
• Page Start: 801
• Page End: 809
• Publication Date: 2016-08-15
• Subjects: Mechanical properties of materials -- Electron beam melting -- Selective laser melting; Engineering design -- Periodicals; 620.004205
• DOI: 10.1108/RPJ-10-2015-0146
• Languages: English
• ISSNs: 1355-2546

Abstract

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.