Selective laser melting of porosity graded lattice structures for bone implants

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

  1. 1.

    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

    Article  Google Scholar 

  2. 2.

    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

    Article  Google Scholar 

  3. 3.

    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

  4. 4.

    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

    Article  Google Scholar 

  5. 5.

    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

    Article  Google Scholar 

  6. 6.

    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

    Article  Google Scholar 

  7. 7.

    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

    Article  Google Scholar 

  8. 8.

    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

    Article  Google Scholar 

  9. 9.

    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

    Article  Google Scholar 

  10. 10.

    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

    Article  Google Scholar 

  11. 11.

    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

    Article  Google Scholar 

  12. 12.

    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

    Article  Google Scholar 

  13. 13.

    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

    Article  Google Scholar 

  14. 14.

    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

    Article  Google Scholar 

  15. 15.

    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

  16. 16.

    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

    Article  Google Scholar 

  17. 17.

    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

    Article  Google Scholar 

  18. 18.

    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

    Article  Google Scholar 

  19. 19.

    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

    Article  Google Scholar 

  20. 20.

    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

    Article  Google Scholar 

  21. 21.

    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

    Article  Google Scholar 

  22. 22.

    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

    Article  Google Scholar 

  23. 23.

    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

    Article  Google Scholar 

  24. 24.

    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

    Article  Google Scholar 

  25. 25.

    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

    Article  Google Scholar 

  26. 26.

    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

    Article  Google Scholar 

  27. 27.

    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

    Article  Google Scholar 

  28. 28.

    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

    Article  Google Scholar 

  29. 29.

    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

    Article  Google Scholar 

  30. 30.

    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

    Article  Google Scholar 

  31. 31.

    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

  32. 32.

    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

    Article  Google Scholar 

  33. 33.

    Schwanekamp T, Bräuer M, Reuber M (2017) Geometrical and topological potentialities and restrictions in selective laser sintering of customized carbide precision tools 49:

  34. 34.

    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

    Article  Google Scholar 

  35. 35.

    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

    Article  Google Scholar 

  36. 36.

    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

    Article  Google Scholar 

  37. 37.

    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

    Article  Google Scholar 

  38. 38.

    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

    Article  Google Scholar 

  39. 39.

    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

    Article  Google Scholar 

  40. 40.

    Mumtaz K, Hopkinson N (2009) Top surface and side roughness of Inconel 625 parts processed using selective laser melting. Rapid Prototyp J 15

  41. 41.

    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

    Article  Google Scholar 

  42. 42.

    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

    Article  Google Scholar 

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Acknowledgments

We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC; funding reference number 518494).

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Correspondence to Dalia Mahmoud or M. A. Elbestawi.

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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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Keywords

  • Selective laser melting
  • Porosity-graded lattice structures
  • Gyroids
  • Dimensional accuracy
  • Surface integrity