A Round Robin Study for Laser Beam Melting in Metal Powder Bed

Abstract

With its ability to fabricate fully dense three-dimensional structures by selectively melting micro-sized metal powder, the additive manufacturing process of laser beam melting (LBM) is considered by many to be a significant technology that is complementary to the conventional forming and subtractive manufacturing processes. However, even with its ability to fabricate structures with characteristics comparable to conventional fabrication, the LBM process often lacks the consistency and degree of repeatability essential for its industrial acceptance for certain end-product applications. Inconsistency in the characteristics of structures is often related to a combination of variations in system technology, process, and user influence. In order to understand fully the potential and limitations of the LBM process, the paper discusses the design, methodology, and results of a round robin test conducted within the Collaborative Working Group (CWG) lasers in production at the International Academy of Production Engineering (CIRP). Observed mechanical characteristics for samples from each of the participants are presented. The experiments are designed to obtain data related to mechanical characteristics for different build orientations and processing conditions in addition to the inherent system technology variations. The paper further discusses the observed process phenomena and their association with the induced mechanical characteristics. OPSOMMINGDie additiewe laserstraal smeltproses word deur kenners as ʼn noemenswaardige tegnologie wat bydra tot die konvensionele vorming-en masjineringvervaardigingsprosesse geag, omdat dit oor die vermoë beskik om digte, driedimensionele strukture te vervaardig. Selfs met dié vermoë om strukture met eienskappe soortgelyk aan die konvensioneel vervaardigde strukture, ly die laserstraal smeltproses dikwels aan ʼn tekort aan konsekwentheid en herhaalbaarheid wat krities is tot die industriële aanvaarding daarvan. Die veranderlikheid in die eienskappe van strukture is dikwels verwant aan ʼn kombinasie van variasies in die sisteem tegnologie, proses-en gebruikerinvloed. Hierdie navorsing bespreek ʼn rondomtalie toets wat op verskeie laserstraal smelters, wat by die Internasionale Akademie van Produksieingenieurs (CIRP) in gebruik is, uitgevoer is. Die toetse se mikpunt was om die potensiaal en beperkinge geassosieer met die laserstraal smeltproses beter te verstaan. Die waargeneemde meganiese eienskappe van monsters van elkeen van die monsters word voorgehou. Die eksperimente is ontwerp om data, wat verwant is aan die meganiese eienskappe wanneer verskeie veranderlikes tydens die vervaardigingsproses teenwoordig is, te verkry. Die waargeneemde prosesverskynsels en hul assosiasies met die geïnduseerde meganiese eienskappe, word dan bespreek.

Laser Powder Bed Fusion of Polymers: Quantitative Research Direction Indices

“…The machine types and the variability between them and operators may be expected to affect processing and as-built part property variations. To control that, round-robin or inter-laboratory studies for L-PBF of metal powders study the variation in the mechanical properties of as-built parts between study partners, proving that it is much higher than the variability between the parts produced by the same user [ 117 , 118 , 119 ]. Consequently, round-robin studies for L-PBF of polymer powder feedstocks represent a promising approach to better understand the determinants of repeatability and reproducibility of the process and further control the factors that affect them.…”

Nanoparticle Additivation Effects on Laser Powder Bed Fusion of Metals and Polymers—A Theoretical Concept for an Inter-Laboratory Study Design All Along the Process Chain, Including Research Data Management

“…Note that previous ILS [50][51][52][53][54][55][56][57][58][59] started introducing commercially available powder feedstocks followed by measuring one or two properties of the as-built parts for statistical evaluation of the measured metrics' repeatability and reproducibility between different machine users. However, the ILS proposed herein includes testing NPs additivated metal and polymer powder feedstocks; hence, the ILS design needs to have additional workflows.…”

“…The tensile test is the most common method that can quantify the effect of NPs on as-built parts and can be used both for polymer and metals. Depending on the building direction within the build job volume, parts can exhibit different tensile behavior [55,57]. It is highly recommended to build test specimens in three directions: vertical, horizontal, and diagonal to the building direction.…”

A Review of Factors Affecting the Mechanical Properties of Maraging Steel 300 Fabricated via Laser Powder Bed Fusion

“…Part density is compromised by imperfections such as regions of un-melted powder, and the presence of voids/porosity and inclusions [39][40][41]. Porosity reduces the fabricated component's effective cross-sectional area and can act as stress raisers and potential loci for fracture initiation [5,39]. Lower fatigue strengths have been reported for L-PBF components due to these defects [42].…”

“…Since the mid-1990s, there have been major advancements in controlling the L-PBF technology's underlying physics, and as a result, it became less complicated to implement in practice, and has become much more prevalent in recent years [1][2][3]. Metal L-PBF systems are well suited to serial Since the mid-1990s, there have been major advancements in controlling the L-PBF technology's underlying physics, and as a result, it became less complicated to implement in practice, and has become production as they provide consistent and repeatable outputs and are capable of producing metallic components with the durability, quality, and precision suitable for industrial applications [4][5][6][7][8][9]. On account of the demand, the range of L-PBF processable materials has been expanding simultaneously, where so far, the compositions have closely followed that of standard alloys.…”