The Need for Powder Characterisation in the Additive Manufacturing Industry and the Establishment of a National Facility

Abstract

The characteristics of powders used in additive manufacturing can have significant effects on process efficiencies and the quality of the final products. Powder sizes and morphologies need to be optimised for a particular process, and this requires the facilities to perform these measurements as well as provide a quality check on powder batches that are purchased. The establishment of a national powder characterisation facility has been identified by the Titanium Centre of Competence (a DST-funded initiative) as a critical form of support for the development of a South African titanium metal industry. This paper discusses what effect the different powder characteristics can have on the selective laser sintering processes, as well as the state of development of this national facility. OPSOMMINGDie eienskappe van die poeiers wat gebruik word vir toevoegingsvervaardiging kan 'n noemenswaardige invloed op die prosesdoeltreffendheid en die gehalte van die finale produkte hê. Poeiergroottes en morfologieë moet geoptimeer word vir 'n spesifieke proses en dit vereis dat fasiliteite hierdie metings moet doen. Die gehalte van die poeier lotte moet ook verseker word. Die daarstelling van 'n nasionale poeier karakteriseringsfasiliteit is deur die Titaan Bevoegdheidsentrum identifiseer as 'n kritiese ondersteuningsmiddel vir die ontwikkeling van 'n Suid-Afrikaanse titaanmetaalindustrie. Hierdie artikel bespreek die effek van verskillende poeiereienskappe op die selektiewe lasersinterprosesse asook die ontwikkeling status van hierdie nasionale fasiliteit. #This article is an extension of a paper presented at

Powder Recycling Effects on the Tensile and Fatigue Behavior of Additively Manufactured Ti-6Al-4V Parts

“…2 Powder properties have been classified based on their morphology such as particle size, shape, and surface roughness; chemistry including the bulk and surface chemistry; and microstructure consisting of internal porosity and crystal structure. [3][4][5] Properties such as particle size distribution (PSD), flowability, and oxygen content have been shown to affect the properties of the AM fabricated parts. 1,[6][7][8][9][10][11][12][13][14] For example, Nandwana et al 8 found that variations in PSD and apparent/bulk density affected the porosity of the parts fabricated from Ti-6Al-4V.…”

Experimental investigation of the effect of processing parameters on densification, microstructure and hardness of selective laser melted 7075 aluminium alloy

“…Spherical, or rounded shape powder particles are more desired due to better flow behavior [27,28]. Benson and Synders [29] reported a better flow rate with spherical powder particles. Spherical particles also give enhanced compaction and structurally better parts [10,30,31].…”

Binder jetting additive manufacturing process fundamentals and the resultant influences on part quality.

“…A similar trend has been reported by Teunou [33] for flowabilty of powder materials with different particle sizes. In Binder Jetting process, high packing density of spread layers is always favorable in that it determines the subsequent mechanical properties, shrinkage, and density of final parts after sintering [38][39][40]. A high packing density depends directly upon the particle size distribution.…”