Reuse of Grade 23 Ti6Al4V Powder during the Laser-Based Powder Bed Fusion Process

Harkin, Ryan; Wu, Hong‐Ke; Nikam, Sagar H.; Quinn, JP; McFadden, Shaun

doi:10.3390/met10121700

Cited by 24 publications

(31 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This investigation shows oxygen content is reduced by sieving, but eventually oxygen accumulates over several reuse cycles. The same analysis as reported in reference [3] showed no significant trend in nitrogen or hydrogen pickup over several cycles, therefore the sieving process shown here is essential in removing oxygen and nitrogen at each stage.…”

Section: Discussionsupporting

confidence: 83%

“…Not only does the recycling minimise the powder property deviation from the virgin state, but also a minimal amount of powder is lost during sieving. Within this study, a mean powder percentage loss of 2.62 ± 2.21 wt.% occurred across the current top-up reuse regime as reported elsewhere [3]. Provided a sufficient quantity of powder, post reuse, is available to complete the subsequent AM build, the two-stage sieving process used within a top-up reuse process is effective for rejuvenating the exposed powder.…”

Section: Discussionsupporting

confidence: 67%

“…Within the broader context across the reuse regime, the oxygen content within the ELI Ti6Al4V powder increased above the maximum limit of the Grade 23 alloy. The regression analysis presented in reference [3] gave a linear slope of 0.004 (wt.% per cycle) with a p-value of 7.84 × 10 −8 . Since this pvalue is less than 0.05, the trend in the oxygen increase over all nine cycles was significant.…”

Section: Discussionmentioning

confidence: 97%

“…The results from the study were taken from a broader top-up study [3]. This was cycle number 7 from a nine-cycle powder reuse regime.…”

Section: Discussionmentioning

confidence: 99%

“…However, prior to the powder being reintroduced back into the production stream it must first be replenished. The quality of the reused powder is intended to remain as close to the virgin powder as possible, but this is difficult to achieve after several reuse stages [3]. Therefore, it is necessary to determine a robust powder handling procedure within an AM processing stream.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Analysis of Spatter Removal by Sieving during a Powder-Bed Fusion Manufacturing Campaign in Grade 23 Titanium Alloy

Harkin

Nikam

et al. 2021

Metals

Self Cite

View full text Add to dashboard Cite

The Laser-based Powder Bed Fusion (L-PBF) process uses a laser beam to selectively melt powder particles deposited in a layer-wise fashion to manufacture components derived from Computer-Aided Design (CAD) information. During laser processing, material is ejected from the melt pool and is known as spatter. Spatter particles can have undesirable geometries for the L-PBF process, thereby compromising the quality of the powder for further reuse. An integral step in any powder replenishing and reuse procedure is the sieving process. The sieving process captures spatter particles within the exposed powder that have a diameter larger than a defined mesh size. This manuscript reports on Ti6Al4V (Grade 23) alloy powder that had been subjected to seven reuse iterations, focusing on the characterisation of powder particles that had been captured (i.e., removed) by the sieving processes. Characterisation included chemical composition focusing upon interstitial elements O, N and H (wt.%), particle morphology and particle size analysis. On review of the compositional analysis, the oxygen contents were 0.43 wt.% and 0.40 wt.% within the 63 µm and 50 µm sieve-captured powder, respectively. Additionally, it was found that a minimum of 79% and 63% of spatter particles were present within the captured powder removed by the 63 µm and 50 µm sieves, respectively.

show abstract

Section: Discussionsupporting

confidence: 83%

Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 97%

“…The results from the study were taken from a broader top-up study [3]. This was cycle number 7 from a nine-cycle powder reuse regime.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Analysis of Spatter Removal by Sieving during a Powder-Bed Fusion Manufacturing Campaign in Grade 23 Titanium Alloy

Harkin

Nikam

et al. 2021

Metals

Self Cite

View full text Add to dashboard Cite

show abstract

Direct metal laser sintering of Ti-6Al-4V parts with reused powder

Contaldi¹,

Corrado²,

et al. 2022

Int J Adv Manuf Technol

View full text Add to dashboard Cite

Ti-6Al-4V alloy is characterised by having excellent mechanical properties and corrosion resistance combined with low specific weight and biocompatibility. This material is ideal for many high-performance engineering applications. It is increasingly used in additive manufacturing (AM) thanks to the possibility of producing very complex lightweight structures, often not achievable with conventional manufacturing techniques, as well as to easily customise products according to specific customer requirements. In powder bed fusion (PBF) processes, only a small percentage of the powder is actually melted and solidified to achieve the final part while most is left after the build. Since the surface morphology and chemistry, the shape and size distribution of the un-melted particles are inevitably modified during the process, and this may affect the resulting properties of the final products, many companies tend to use virgin powders for AM builds to keep compliance with manufacturing requirements and minimise risk. From both an economic and environmental point of view, it results crucial to develop recycling methods to reuse the metal powder as many times as possible while maintaining compliance with manufacturing standards. In this work, the effect of Ti-6Al-4V powder reuse on the evolution of powder characteristics and mechanical properties of final products additively manufactured is investigated through a systematic approach based on design of experiments.

show abstract

Evaluation of the role of hatch-spacing variation in a lack-of-fusion defect prediction criterion for laser-based powder bed fusion processes

Harkin

Wu²,

Nikam³

et al. 2023

Int J Adv Manuf Technol

Self Cite

View full text Add to dashboard Cite

Lack of fusion (LOF) defects impact adversely on the mechanical properties of additively manufactured components produced via laser-based powder bed fusion. Following a stress-relieving heat treatment, the tensile properties and hardness of Ti6Al4V components were found to be negatively impacted by the presence of LOF defects. This work considers a geometrical-based inequality for the prediction of LOF defects. We critically evaluate an LOF criterion using both the experimentally and analytically obtained melt pool geometries. Experimentally, we determined melt pool dimensions by analysing a single-layer, multi-track deposition with oversized hatch spacing in order to establish depth and width from non-overlapping melt pools. Analytically, Rosenthal-based predictions of melt pool size (width and depth) are applied. To investigate LOF defects, we used hatch spacing as the main parameter variation to investigate defects while keeping all other controllable parameters unchanged. An original LOF criterion from the literature was found to be an adequate predictor of LOF defects when experimentally obtained melt pool geometry was used. Critically, however, the analytical expressions for melt pool geometry were found to be in error and this caused the LOF criterion to fail in predicting LOF defects in all cases where defects were observed experimentally. However, an adaptation to the LOF prediction criterion is proposed whereby it is recommended that a correction factor $${R}_{c}^{2}=0.7$$ R c 2 = 0.7 (or $${R}_{c}=0.83$$ R c = 0.83 ) is used with the analytically derived melt pool geometry. Furthermore, this correction is extended into the laser power versus scanning speed operating space to give minimum (corrected) line energy for LOF avoidance in Ti6Al4V components.

show abstract

Reuse of Grade 23 Ti6Al4V Powder during the Laser-Based Powder Bed Fusion Process

Cited by 24 publications

References 20 publications

Analysis of Spatter Removal by Sieving during a Powder-Bed Fusion Manufacturing Campaign in Grade 23 Titanium Alloy

Analysis of Spatter Removal by Sieving during a Powder-Bed Fusion Manufacturing Campaign in Grade 23 Titanium Alloy

Direct metal laser sintering of Ti-6Al-4V parts with reused powder

Evaluation of the role of hatch-spacing variation in a lack-of-fusion defect prediction criterion for laser-based powder bed fusion processes

Contact Info

Product

Resources

About