A comprehensive study on variability of relative density in selective laser melting of Ti-6Al-4V

ABSTRACT In this research, the effects of Selective Laser Melting (SLM) process parameters comprising laser power, scan speed, hatch space and scan pattern angle on the formation of porosity and subsequently density have been analysed. To improve the mechanical properties, post-processes (heat treatment) must be performed. Therefore, heat treatment was added to the design of experiment to analyse the effect of this process coupling with SLM process parameters on the value of density. A comprehensive design set with five levels for each parameter was selected so Taguchi L25 was used as the design of experiment. The significance of each parameter on obtained results was examined using statistical analysis (F-Test) and numerical model (interrogator analysis). The correlation between two process parameters was discussed by using 3D analytical and contour plots and the mechanisms behind these were discussed in depth. The contribution of this paper is a deep investigation of the relation of process parameters and heat treatment on density based on the Artificial Neural Network model. Results showed that better density is obtained with lower scan speed, laser power and scanning pattern angle. Meanwhile, for heat treatment and hatch space, the best density was obtained in their optimum range.

[1]  Ian Gibson,et al.  The effect of SLM process parameters on density, hardness, tensile strength and surface quality of Ti-6Al-4V , 2019, Additive Manufacturing.

[2]  D. C. Blaine,et al.  Numerical comparison of lattice unit cell designs for medical implants by additive manufacturing , 2018, Virtual and Physical Prototyping.

[3]  I. Gibson,et al.  Rheological characterization of process parameters influence on surface quality of Ti-6Al-4V parts manufactured by selective laser melting , 2018, The International Journal of Advanced Manufacturing Technology.

[4]  Xigen Zhou,et al.  Role of martensite decomposition in tensile properties of selective laser melted Ti-6Al-4V , 2018 .

[5]  Hong Wu,et al.  Novel Mg-based alloys by selective laser melting for biomedical applications: microstructure evolution, microhardness and in vitro degradation behaviour , 2018 .

[6]  I. Gibson,et al.  Mass transfer and flow in additive manufacturing of a spherical component , 2018 .

[7]  F. Calignano.  Investigation of the accuracy and roughness in the laser powder bed fusion process , 2018 .

[8]  Johann Sienz,et al.  The three-prong method: a novel assessment of residual stress in laser powder bed fusion , 2018 .

[9]  Kai Zeng,et al.  A review of defect modeling in laser material processing , 2017 .

[10]  I. Gibson,et al.  Production of Ti-6Al-4V acetabular shell using selective laser melting: possible limitations in fabrication , 2017 .

[11]  I. Gibson,et al.  Thermal stress flow analysis in fabrication of acetabular shells using SLM , 2017 .

[12]  M. Leu,et al.  Powder characterisation techniques and effects of powder characteristics on part properties in powder-bed fusion processes , 2017 .

[13]  Xinhua Wu,et al.  Influences of processing parameters on surface roughness of Hastelloy X produced by selective laser melting , 2017 .

[14]  I. Gibson,et al.  A survey on mechanisms and critical parameters on solidification of selective laser melting during fabrication of Ti-6Al-4V prosthetic acetabular cup , 2016 .

[15]  Moataz M. Attallah,et al.  On the role of melt flow into the surface structure and porosity development during selective laser melting , 2015 .

[16]  I. Yadroitsava,et al.  Evaluation of residual stress in stainless steel 316L and Ti6Al4V samples produced by selective laser melting , 2015 .

[17]  Chee Kai Chua,et al.  Fabrication and microstructural characterisation of additive manufactured Ti-6Al-4V parts by electron beam melting , 2015 .

[18]  Han Huang,et al.  Effect of substrate temperature on the interface bond between support and substrate during selective laser melting of Al-Ni-Y-Co-La metallic glass , 2015 .

[19]  Ian Gibson,et al.  Additive manufacturing technologies : 3D printing, rapid prototyping, and direct digital manufacturing , 2015 .

[20]  C. Tuck,et al.  Effect of the build orientation on the mechanical properties and fracture modes of SLM Ti–6Al–4V , 2014 .

[21]  J. Ziaja.  Titanium Alloys - Advances in Properties Control , 2013 .

[22]  J. Sieniawski,et al.  Microstructure and Mechanical Properties of High Strength Two-Phase Titanium Alloys , 2013 .

[23]  I. Yadroitsava,et al.  Energy input effect on morphology and microstructure of selective laser melting single track from metallic powder , 2013 .

[24]  L. Hao,et al.  Effect of selective laser melting layout on the quality of stainless steel parts , 2012 .

[25]  Ph. Bertrand,et al.  Studying the influence of initial powder characteristics on the properties of final parts manufactured by the selective laser melting technology , 2011 .

[26]  H. Maier,et al.  In situ characterization of the deformation and failure behavior of non-stochastic porous structures processed by selective laser melting , 2011 .

[27]  Gideon Levy,et al.  Influence of the particle size distribution on surface quality and mechanical properties in AM steel parts , 2011 .

[28]  Konrad Wissenbach,et al.  Ductility of a Ti‐6Al‐4V alloy produced by selective laser melting of prealloyed powders , 2010 .

[29]  Rémy Glardon,et al.  On the effect of scanning strategies in the selective laser melting process , 2010 .

[30]  Jean-Pierre Kruth,et al.  Charpy impact testing of metallic selective laser melting parts , 2010 .

[31]  B. Baufeld,et al.  Additive manufacturing of Ti–6Al–4V components by shaped metal deposition: Microstructure and mechanical properties , 2010 .

[32]  L. Murr,et al.  Microstructure and mechanical behavior of Ti-6Al-4V produced by rapid-layer manufacturing, for biomedical applications. , 2009, Journal of the mechanical behavior of biomedical materials.

[33]  David W. Rosen,et al.  Additive Manufacturing Technologies: Rapid Prototyping to Direct Digital Manufacturing , 2009 .

[34]  Jean Berthier,et al.  Microdrops and digital microfluidics , 2008 .

[35]  Thomas Schweizer,et al.  Rheology. Concepts, Methods, and Applications , 2006 .

[36]  S. Zec,et al.  The effect of annealing temperatures and cooling rates on microstructure and mechanical properties of investment cast Ti–6Al–4V alloy , 2006 .

[37]  Ian Gibson,et al.  Rapid prototyping for architectural models , 2002 .

[38]  P. V. Loocke,et al.  QNET: a quantum mechanical neural network. A new connectionist architecture and its relevance for variable binding and constraint satisfaction problems , 1995 .

[39]  E. Collings,et al.  Materials Properties Handbook: Titanium Alloys , 1994 .