Abstract
Porosity-graded lattice structures are used in bone implants to mimic natural bone properties. Rather than having uniform pore size distribution, the size distribution is gradually changed in a certain direction to achieve specific mechanical and biological properties. Selective laser melting (SLM) has been used to print uniform metallic lattice structures with high accuracy. However, the accuracy of SLM in printing lattice structures with a wide range of pore sizes and volume fractions needs to be defined. The effect of SLM process scanning strategies on morphological properties of graded porosity metallic lattice structures is investigated in this study. Three different scanning strategies are proposed, and their effect on volume fraction, strut size, and surface integrity is investigated. Characterization of the printed parts reveals that the effect of different scanning strategies on the morphological quality is highly dependent on the design volume fraction for the chosen unit cell design. It was noted that using hatching strategies results in better dimensional accuracy and surface integrity in high-volume fraction lattice structures. While the use of total fill scanning strategy resulted in significantly distorted geometries in high-volume fractions. However, in lower-volume fractions, the dimensional accuracy as well as the surface integrity are comparable to that of hatching strategies. This work highlights the importance of understanding the limitations and capabilities of the SLM process in this application, and to enhance the printing quality of porosity-graded metallic lattice structures.
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References
Cronskär M, Bäckström M, Rännar L-E (2013) Production of customized hip stem prostheses—a comparison between conventional machining and electron beam melting (EBM). Rapid Prototyp J 19:365–372. https://doi.org/10.1108/RPJ-07-2011-0067
Harrysson OLA, Cansizoglu O, Marcellin-Little DJ, Cormier DR, West HA II (2008) Direct metal fabrication of titanium implants with tailored materials and mechanical properties using electron beam melting technology. Mater Sci Eng C 28:366–373. https://doi.org/10.1016/j.msec.2007.04.022
Huiskes R, Weinans H, van Rietbergen B (1992) The relationship between stress shielding and bone resorption around total hip stems and the effects of flexible materials. Clin Orthop Relat Res:124–134. https://doi.org/10.1097/00003086-199201000-00014
Van Der Stok J, Van Der Jagt OP, Amin Yavari S et al (2013) Selective laser melting-produced porous titanium scaffolds regenerate bone in critical size cortical bone defects. J Orthop Res 31:792–799. https://doi.org/10.1002/jor.22293
Abele E, Stoffregen HA, Kniepkamp M, Lang S, Hampe M (2015) Selective laser melting for manufacturing of thin-walled porous elements. J Mater Process Technol 215:114–122. https://doi.org/10.1016/j.jmatprotec.2014.07.017
Helou M, Kara S (2017) Design, analysis and manufacturing of lattice structures: an overview. Int J Comput Integr Manuf 31:243–261. https://doi.org/10.1080/0951192X.2017.1407456
Rajagopalan S, Robb RA (2006) Schwarz meets Schwann: design and fabrication of biomorphic and durataxic tissue engineering scaffolds. Med Image Anal 10:693–712. https://doi.org/10.1016/j.media.2006.06.001
Almeida HA, Bártolo PJ (2014) Design of tissue engineering scaffolds based on hyperbolic surfaces: structural numerical evaluation. Med Eng Phys 36:1033–1040. https://doi.org/10.1016/j.medengphy.2014.05.006
Yan C, Hao L, Hussein A, Young P (2015) Ti–6Al–4V triply periodic minimal surface structures for bone implants fabricated via selective laser melting. J Mech Behav Biomed Mater 51:61–73. https://doi.org/10.1016/j.jmbbm.2015.06.024
Kumar A, Nune KC, Murr LE, Misra RDK (2016) Biocompatibility and mechanical behaviour of three-dimensional scaffolds for biomedical devices: process–structure–property paradigm. Int Mater Rev 61:20–45. https://doi.org/10.1080/09506608.2015.1128310
Taniguchi N, Fujibayashi S, Takemoto M, Sasaki K, Otsuki B, Nakamura T, Matsushita T, Kokubo T, Matsuda S (2016) Effect of pore size on bone ingrowth into porous titanium implants fabricated by additive manufacturing: an in vivo experiment. Mater Sci Eng C 59:690–701. https://doi.org/10.1016/j.msec.2015.10.069
Ahmadi SM, Yavari SA, Wauthle R, Pouran B, Schrooten J, Weinans H, Zadpoor A (2015) Additively manufactured open-cell porous biomaterials made from six different space-filling unit cells: the mechanical and morphological properties. Materials (Basel) 8:1871–1896. https://doi.org/10.3390/ma8041871
Zhang S, Li C, Hou W, Zhao S, Li S (2016) Longitudinal compression behavior of functionally graded Ti–6Al–4V meshes. J Mater Sci Technol 32:1098–1104. https://doi.org/10.1016/J.JMST.2016.02.008
Al-Saedi DSJ, Masood SH, Faizan-Ur-Rab M et al (2018) Mechanical properties and energy absorption capability of functionally graded F2BCC lattice fabricated by SLM. Mater Des 144:32–44. https://doi.org/10.1016/j.matdes.2018.01.059
Onal E, Frith JE, Jurg M, Wu X, Molotnikov A (2018) Mechanical properties and in vitro behavior of additively manufactured and functionally graded Ti6Al4V porous scaffolds. Metals (Basel) 8. https://doi.org/10.3390/met8040200
Sing SL, Wiria FE, Yeong WY (2018) Selective laser melting of lattice structures: a statistical approach to manufacturability and mechanical behavior. Robot Comput Integr Manuf 49:170–180. https://doi.org/10.1016/j.rcim.2017.06.006
Sing SL, Yeong WY, Wiria FE, Tay BY (2016) Characterization of titanium lattice structures fabricated by selective laser melting using an adapted compressive test method. Exp Mech 56:735–748. https://doi.org/10.1007/s11340-015-0117-y
Ahmadi SM, Hedayati R, Ashok Kumar Jain RK, Li Y, Leeflang S, Zadpoor AA (2017) Effects of laser processing parameters on the mechanical properties, topology, and microstructure of additively manufactured porous metallic biomaterials: a vector-based approach. Mater Des 134:234–243. https://doi.org/10.1016/j.matdes.2017.08.046
Dai D, Gu D, Zhang H, Xiong J, Ma C, Hong C, Poprawe R (2018) Influence of scan strategy and molten pool configuration on microstructures and tensile properties of selective laser melting additive manufactured aluminum based parts. Opt Laser Technol 99:91–100. https://doi.org/10.1016/J.OPTLASTEC.2017.08.015
Ghouse S, Babu S, Van Arkel RJ et al (2017) The influence of laser parameters and scanning strategies on the mechanical properties of a stochastic porous material. Mater Des 131:498–508. https://doi.org/10.1016/j.matdes.2017.06.041
Kapfer SC, Hyde ST, Mecke K, Arns CH, Schröder-Turk GE (2011) Minimal surface scaffold designs for tissue engineering. Biomaterials 32:6875–6882. https://doi.org/10.1016/j.biomaterials.2011.06.012
Melchels FPW, Bertoldi K, Gabbrielli R, Velders AH, Feijen J, Grijpma DW (2010) Mathematically defined tissue engineering scaffold architectures prepared by stereolithography. Biomaterials 31:6909–6916. https://doi.org/10.1016/j.biomaterials.2010.05.068
Melancon D, Bagheri ZS, Johnston RB, Liu L, Tanzer M, Pasini D (2017) Mechanical characterization of structurally porous biomaterials built via additive manufacturing: experiments, predictive models, and design maps for load-bearing bone replacement implants. Acta Biomater 63:350–368. https://doi.org/10.1016/j.actbio.2017.09.013
Arabnejad S, Burnett Johnston R, Pura JA, Singh B, Tanzer M, Pasini D (2016) High-strength porous biomaterials for bone replacement: a strategy to assess the interplay between cell morphology, mechanical properties, bone ingrowth and manufacturing constraints. Acta Biomater 30:345–356. https://doi.org/10.1016/j.actbio.2015.10.048
Bobbert FSL, Lietaert K, Eftekhari AA, Pouran B, Ahmadi SM, Weinans H, Zadpoor AA (2017) Additively manufactured metallic porous biomaterials based on minimal surfaces: a unique combination of topological, mechanical, and mass transport properties. Acta Biomater 53:572–584. https://doi.org/10.1016/j.actbio.2017.02.024
Heinl P, Müller L, Körner C, Singer RF, Müller FA (2008) Cellular Ti-6Al-4V structures with interconnected macro porosity for bone implants fabricated by selective electron beam melting. Acta Biomater 4:1536–1544. https://doi.org/10.1016/j.actbio.2008.03.013
Yang J, Cai H, Lv J, Zhang K, Leng H, Sun C, Wang Z, Liu Z (2014) In vivo study of a self-stabilizing artificial vertebral body fabricated by Electron beam melting. Spine (Phila Pa 1976) 39:E486–E492. https://doi.org/10.1097/BRS.0000000000000211
Walker JM, Bodamer E, Kleinfehn A, Luo Y, Becker M, Dean D (2017) Design and mechanical characterization of solid and highly porous 3D printed poly(propylene fumarate) scaffolds. Prog Addit Manuf 2:99–108. https://doi.org/10.1007/s40964-017-0021-3
Rack HJ, Qazi JI (2006) Titanium alloys for biomedical applications. Mater Sci Eng C 26:1269–1277. https://doi.org/10.1016/j.msec.2005.08.032
Mercelis P, Kruth J, Kruth J-P (2006) Residual stresses in selective laser sintering and selective laser melting residual stresses in selective laser sintering and selective laser melting. Rapid Prototyp 12:254–265
Kruth J-P, Deckers J, Yasa E, Wauthlé R Assessing and comparing influencing factors of residual stresses in selective laser melting using a novel analysis method. https://doi.org/10.1177/0954405412437085
Kudzal A, McWilliams B, Hofmeister C, Kellogg F, Yu J, Taggart-Scarff J, Liang J (2017) Effect of scan pattern on the microstructure and mechanical properties of powder bed fusion additive manufactured 17-4 stainless steel. Mater Des 133:205–215. https://doi.org/10.1016/J.MATDES.2017.07.047
Schwanekamp T, Bräuer M, Reuber M (2017) Geometrical and topological potentialities and restrictions in selective laser sintering of customized carbide precision tools 49:
Ter HG, Becker T (2018) Selective laser melting produced Ti-6Al-4V: post-process heat treatments to achieve superior tensile properties. Materials (Basel) 11:146. https://doi.org/10.3390/ma11010146
Ho ST, Hutmacher DW (2006) A comparison of micro CT with other techniques used in the characterization of scaffolds. Biomaterials 27:1362–1376. https://doi.org/10.1016/J.BIOMATERIALS.2005.08.035
Ataee A, Li Y, Fraser D, Song G, Wen C (2018) Anisotropic Ti-6Al-4V gyroid scaffolds manufactured by electron beam melting (EBM) for bone implant applications. Mater Des 137:345–354. https://doi.org/10.1016/j.matdes.2017.10.040
Han C, Li Y, Wang Q, Wen S, Wei Q, Yan C, Hao L, Liu J, Shi Y (2018) Continuous functionally graded porous titanium scaffolds manufactured by selective laser melting for bone implants. J Mech Behav Biomed Mater 80:119–127. https://doi.org/10.1016/j.jmbbm.2018.01.013
Su X, Yang Y (2012) Research on track overlapping during selective laser melting of powders. J Mater Process Technol 212:2074–2079. https://doi.org/10.1016/J.JMATPROTEC.2012.05.012
Kruth JP, Froyen L, Van Vaerenbergh J et al (2004) Selective laser melting of iron-based powder. J Mater Process Technol 149:616–622. https://doi.org/10.1016/J.JMATPROTEC.2003.11.051
Mumtaz K, Hopkinson N (2009) Top surface and side roughness of Inconel 625 parts processed using selective laser melting. Rapid Prototyp J 15
Gu D, Shen Y (2009) Balling phenomena in direct laser sintering of stainless steel powder: metallurgical mechanisms and control methods. Mater Des 30:2903–2910. https://doi.org/10.1016/J.MATDES.2009.01.013
Mumtaz KA, Hopkinson N (2010) Selective laser melting of thin wall parts using pulse shaping. J Mater Process Technol 210:279–287. https://doi.org/10.1016/J.JMATPROTEC.2009.09.011
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We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC; funding reference number 518494).
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Mahmoud, D., Elbestawi, M.A. Selective laser melting of porosity graded lattice structures for bone implants. Int J Adv Manuf Technol 100, 2915–2927 (2019). https://doi.org/10.1007/s00170-018-2886-9
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DOI: https://doi.org/10.1007/s00170-018-2886-9