Morphology and surface topography of Ti6Al4V lattice structure fabricated by selective laser sintering

Abstract

Abstract. Construction of metallic implants with a porous structure that mimics the biomechanical properties of bone is one of the challenges of orthopedic regenerative medicine. The selective laser sintering technique (SLS) allows the production of complex geometries based on three-dimensional model, which offers the prospect of preparing porous metal implants, in which stiffness and porosity can be precisely adjusted to the individual needs of the patient. This requires an interdisciplinary approach to design, manufacturing and testing of porous structures manufactured by selective sintering. An important link in this process is the ability to assess the surface topography of the struts of porous structure. The paper presents a qualitative assessment of the surface morphology based on SEM studies and methodology that allows for quantitative assessment of stereometric structure based on micro-tomographic measurements.Key words: metal porous implant, selective laser sintering, surface roughness, X-ray microtomography.Morphology and surface topography of Ti6Al4V lattice structure fabricated by selective laser sintering tain an implant with a defined pore structure. An alternative to traditional methods of manufacturing metallic porous material is rapid prototyping by selective laser sintering (SLS) or selective electron beam melting (EBM). The ability to produce complex geometric shapes based on three-dimensional CAD model allows for precise control of not only the product geometry itself, but also of shape, size and distribution of pores in the proposed structure.Taking into account requirements set for porous medical implants, design, manufacturing and testing of porous structures manufactured by SLS require an interdisciplinary approach. An important role in this process is played, among other things, by verification of the accuracy of the porous implant 3d geometry and the evaluation of the surface topography of the struts. Nowadays a large number of instruments for measuring surface roughness is available [12]. Most often they operate on the basis of the profile method. Data is collected based on the points arranged in a line or based on image registration from different positions. The choice of specific method is determined by the purpose and conditions of measurement [13,14]. The measurement of surface roughness inside the porous structures manufactured by selective laser sintering is practically not achievable (without destroying the object) by conventional methods. An alternative is constituted by x-ray microtomography. The authors' [15, 16] work studies have shown that in case of a relatively large surface roughness (micro-scale) a comparable, or even better accuracy can be achieved using the mentioned method than with conventional measuring methods. For the measurements of small surface roughness (sub-micronscale) limitation may constitute spatial resolution of the images and noise. The aim of this study is to investigate the morphology and the surface topography of the Ti6Al4V porous structure produc...

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