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Faculté des Sciences appliquées
Faculté des Sciences appliquées
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Quality assessment of highly productive selective laser melting processes

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Ducarme, Paul ULiège
Promotor(s) : Béchet, Eric ULiège
Date of defense : 9-Sep-2019/10-Sep-2019 • Permalink : http://hdl.handle.net/2268.2/7846
Details
Title : Quality assessment of highly productive selective laser melting processes
Translated title : [fr] Évaluation de la qualité des processus de fusion laser sélective hautement productifs
Author : Ducarme, Paul ULiège
Date of defense  : 9-Sep-2019/10-Sep-2019
Advisor(s) : Béchet, Eric ULiège
Committee's member(s) : Ponthot, Jean-Philippe ULiège
Mertens, Anne ULiège
Cocle, Roger 
Language : English
Number of pages : 120
Keywords : [en] Selective laser melting
[en] AlSi10Mg
[en] 316L
[en] Highly productive
[en] Experiments
[en] Density
[en] Surface roughness
[en] Layer thickness
[en] Parameters
[en] Power
[en] Scanning speed
[en] Hatch spacing
Discipline(s) : Engineering, computing & technology > Mechanical engineering
Engineering, computing & technology > Materials science & engineering
Funders : Any-Shape
Target public : Researchers
Professionals of domain
Student
General public
Institution(s) : Université de Liège, Liège, Belgique
Degree: Master en ingénieur civil mécanicien, à finalité spécialisée en génie mécanique
Faculty: Master thesis of the Faculté des Sciences appliquées

Abstract

[en] The thesis aims at determining suitable selective laser melting process parameters enabling high productivity and sufficient part quality, for two materials: the aluminium alloy AlSi10Mg and the stainless steel SS316L.
To do that, the concept of productivity is first defined. On that basis, a strategy to optimize it is determined. It consists of finding adequate exposure parameters (power, scanning speed, hatch spacing, contour powers and contour scanning speeds) leading to a high relative density and low surface roughness, when the layer thickness is set to 0.1 mm (AlSi10Mg) and 0.08 mm (SS316L).
Experiments consisting of printing small cubes with different sets of parameters are conducted. Selecting test series parameters is reasoned using an index, which provides an estimation of the lack of fusion porosity that should be expected given a combination of power, scanning speed, hatch spacing and layer thickness.
Relative density is measured through Archimede’s method and micrography. AlSi10Mg and SS316L samples associated to a high index show lack-of-fusion pores. Besides, AlSi10Mg samples manufactured with low scanning speeds are subjected to spherical porosity, due to hydrogen bubbles that had time to grow in the melt pool before being trapped by solidification, most likely. SS316L samples present keyhole pores at high-energy-density regimes and porosity due to Plateau-Rayleigh instability at high-power-and-scanning-speed regimes.
Regarding surface quality, AlSi10Mg samples show a lower roughness when linear energy density is increased using two pre-contours, whereas SS316L samples present a better surface quality with one post-contour. Best surface roughness obtained after sandblasting is 6 μm for AlSi10Mg and 7 μm for SS316L.
Based on the conclusions of the experiments, a model is built to delimit windows of parameters leading to a sufficiently high density. Optimal sets regarding productivity are selected inside the windows. Predicted build rates are 16.5 mm3/s and 9.6 mm3/s for AlSi10Mg and SS316L, respectively. They increase current volume build rates by 58% and 159%, respectively.


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Author

  • Ducarme, Paul ULiège Université de Liège > Master ing. civ. méc., à fin.

Promotor(s)

Committee's member(s)

  • Ponthot, Jean-Philippe ULiège Université de Liège - ULiège > Département d'aérospatiale et mécanique > LTAS-Mécanique numérique non linéaire
    ORBi View his publications on ORBi
  • Mertens, Anne ULiège Université de Liège - ULiège > Département d'aérospatiale et mécanique > Science des matériaux métalliques
    ORBi View his publications on ORBi
  • Cocle, Roger Any Shape
  • Total number of views 38
  • Total number of downloads 1










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