Abstract

In recent years, the application field of laser powder bed fusion of metals and polymers extends through an increasing variability of powder compositions in the market. New powder formulations such as nanoparticle (NP) additivated powder feedstocks are available today. Interestingly, they behave differently along with the entire laser powder bed fusion (PBF-LB) process chain, from flowability over absorbance and microstructure formation to processability and final part properties. Recent studies show that supporting NPs on metal and polymer powder feedstocks enhances processability, avoids crack formation, refines grain size, increases functionality, and improves as-built part properties. Although several inter-laboratory studies (ILSs) on metal and polymer PBF-LB exist, they mainly focus on mechanical properties and primarily ignore nano-additivated feedstocks or standardized assessment of powder feedstock properties. However, those studies must obtain reliable data to validate each property metric’s repeatability and reproducibility limits related to the PBF-LB process chain. We herein propose the design of a large-scale ILS to quantify the effect of nanoparticle additivation on powder characteristics, process behavior, microstructure, and part properties in PBF-LB. Besides the work and sample flow to organize the ILS, the test methods to measure the NP-additivated metal and polymer powder feedstock properties and resulting part properties are defined. A research data management (RDM) plan is designed to extract scientific results from the vast amount of material, process, and part data. The RDM focuses not only on the repeatability and reproducibility of a metric but also on the FAIR principle to include findable, accessible, interoperable, and reusable data/meta-data in additive manufacturing. The proposed ILS design gives access to principal component analysis (PCA) to compute the correlations between the material–process–microstructure–part properties.

Highlights

  • Powder bed fusion using laser beam (PBF-LB) [1] is a sub-class production technique of additive manufacturing (AM)

  • The chemical composition of an unmodified metal or polymer powder feedstock directly affects the laser interaction, process window, microstructural formations, and as-built part properties [2,3,35]. These properties can be further affected by NPs’ chemical composition, supported amount, and surface coverage levels [29,30,31,32,33,38,39]. In this inter-laboratory studies (ILSs), the chemical composition of powder feedstock is recommended to be measured by X-ray fluorescence (XRF) and inductively coupled coupled for plasma-optical emission spectroscopy (ICP-OES)

  • As-builtpart partproperty propertyanalysis analysis with related measurement techniques for nanoparticle-additivated and Figure with related measurement techniques for nanoparticle-additivated metalmetal and polypolymer parts, number of replicas for each property measurements per build job, and number of data generated for each mer parts, number of replicas for each property measurements per build job, and number of data generated for each property property metric.backscattered

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Summary

Introduction

Powder bed fusion using laser beam (PBF-LB) [1] is a sub-class production technique of additive manufacturing (AM). Previous ILSs on PBF-LB focused on quantifying the variability in an asproduced and used state of metal [50,51] and polymer [52,53] powder feedstock properties without focusing on processability and as-built part properties They included measurements of powder properties such as powder size distribution (PSD), shape, chemical composition, crystallographic phases, material rheology, flowability, and thermal behavior [50,51,52,53]. It could be demonstrated that the variability of as-build part properties between-participant is higher than within-participant [54,55,56,57,58,59,60], resulting in a strict recommendation to follow a manufacturing plan To overcome these limitations, the proposed design includes the measurement of as-produced and used powder properties and evaluates process parameter sets and asbuilt part properties, including microstructural formation with at least 20 PBF-LB process participants (10 polymers, 10 metals).

Design ofprocess
Additivation of NPs on As-Produced Metal and Polymer Powder Feedstocks
Powder Quality of Unmodified and NP-Additivated Powder Feedstocks
Chemical Composition
Powder Shape and Powder Size Distribution
Flowability
Thermal Behavior
Laser Reflectivity
Moisture Content
PBF-LB Process
Powder Quality of Used Powder Feedstocks
As-Built Parts
As-built
Microstructural Formations
Relative Density and Pore Size Distribution
NP Imaging
Static Mechanical Properties
Recommended Implementation Procedure
Design
Findings
Conclusions
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