Investigation on the surface integrity in electrical discharge machining of Co-Cr-Mo
Christoph Lerez, Chris Michaelis, Laura Zak, Lukas Blumenröhr, Matthias Hackert-Oschätzchen
Abstract. The electrical discharge machining (EDM) process offers significant advantages over other manufacturing methods, particularly in achieving high surface quality and tight tolerances, irrespective of the material’s mechanical properties. In industrial applications, especially in die-sinking EDM, geometric accuracy and surface quality are primary objectives. Many EDM machines allow surface roughness to be directly selected as a target parameter, reflecting its importance in everyday practice. However, focusing solely on surface roughness neglects a critical aspect: the overall surface integrity, which significantly impacts the durability and performance of manufactured parts. This can be particularly relevant for medical applications, such as Co-Cr-Mo endoprostheses, where the boundary layer properties directly affect wear resistance, crack formation, and functional longevity. Any deterioration in these properties can increase the risk of inflammation and loss of function, emphasizing the importance of comprehensive surface integrity evaluation. This study focuses on investigating the surface integrity of Co-Cr-Mo and the potential changes induced by EDM die sinking. By varying the target surface roughness settings on a commercial EDM die sinking machine, workpieces were systematically manufactured and analyzed. To link the technological parameters with the resulting surface integrity, the workpieces were examined using a range of measurement methods, including confocal microscopy, on-light microscopy, microhardness testing, X-ray diffractometry, cross-sectional analysis, and electron backscatter diffraction. This approach provides a detailed understanding of how EDM processing conditions affect both surface roughness and the broader integrity of the material, with implications for enhancing durability in critical applications like medical implants.
Keywords
Die-Sinking, Surface Integrity, Boundary Layer Properties
Published online 5/7/2025, 9 pages
Copyright © 2025 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Christoph Lerez, Chris Michaelis, Laura Zak, Lukas Blumenröhr, Matthias Hackert-Oschätzchen, Investigation on the surface integrity in electrical discharge machining of Co-Cr-Mo, Materials Research Proceedings, Vol. 54, pp 2121-2129, 2025
DOI: https://doi.org/10.21741/9781644903599-228
The article was published as article 228 of the book Material Forming
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
References
[1] E. Wintermantel, S.-W. Ha: Medizintechnik: Life Science Engineering; Interdisziplinarität, Biokompatibilität, Technologien, Implantate, Diagnostik, Werkstoffe, Business; mit 200 Tabellen. 4., überarb. und erw. Aufl., Berlin, Heidelberg, Springer, 2008 https://doi.org/10.1007/978-3-540-74925-7
[2] S. Affatato (ed.), K. L. Choy (ed.), N. Grujovic (ed.), M. Schnabelrauch (ed.), M. Trajanovic (ed.), F. Zivic (ed.): Biomaterials in Clinical Practice: Advances in Clinical Research and Medical Devices. 1st ed. 2018, Cham, Springer International Publishing; Imprint: Springer, 2018
[3] M. Engelhardt (ed.), M. J. Raschke (ed.): Orthopädie und Unfallchirurgie, Berlin, Heidelberg, zahlreiche Illustrationen, Diagramme, Springer, 2019 (Springer Nature Living Reference Medicine)
[4] J. R. Davis: Nickel, cobalt, and their alloys, Materials Park OH, ASM International, 2000 (ASM specialty handbook)
[5] S. S. Djokić (ed.): Biomedical applications, New York, NY, Heidelberg, Springer, 2012 (Modern aspects of electrochemistry 55.2012) https://doi.org/10.1007/978-1-4614-3125-1
[6] Biomaterials Market Size | Mordor Intelligence. URL https://www.mordorintelligence.com/industry-reports/biomaterials-market – accessed 2024-11-18
[7] A. Grimberg, S. Kirschner, J. Lützner, O. Melsheimer, M. Morlock, A. Steinbrück: EPRD-Jahresbericht 2024 (2024)
[8] A. Mahajan, S. Devgan, D. Kalyanasundaram: Surface alteration of Cobalt-Chromium and duplex stainless steel alloys for biomedical applications: a concise review. In: Materials and Manufacturing Processes 38 (2023), Nr. 3, S. 260-270 https://doi.org/10.1080/10426914.2022.2105873
[9] R. Davis, A. Singh, M. J. Jackson, R. T. Coelho, D. Prakash, C. P. Charalambous, W. Ahmed, L. R. R. Da Silva, A. A. Lawrence: A comprehensive review on metallic implant biomaterials and their subtractive manufacturing. In: The International journal, advanced manufacturing technology 120 (2022), 3-4, S. 1473-1530 https://doi.org/10.1007/s00170-022-08770-8
[10] H. A. Zaman, S. Sharif, D.-W. Kim, M. H. Idris, M. A. Suhaimi, Z. Tumurkhuyag: Machinability of Cobalt-based and Cobalt Chromium Molybdenum Alloys – A Review. In: Procedia Manufacturing 11 (2017), S. 563-570 https://doi.org/10.1016/j.promfg.2017.07.150
[11] M. S. Bahari (ed.), A. Bin Harun (ed.), Z. Z. Abidin (ed.), R. Hamidon (ed.), S. Zakaria (ed.): Intelligent manufacturing and mechatronics: Proceedings of SympoSIMM 2020, Singapore, Springer, 2021 (Lecture notes in mechanical engineering) https://doi.org/10.1007/978-981-16-0866-7
[12] E. Uhlmann, M. Polte, S. Yabroudi: Novel Advances in Machine Tools, Tool Electrodes and Processes for High-Performance and High-Precision EDM. In: Procedia CIRP 113 (2022), S. 611-635 https://doi.org/10.1016/j.procir.2022.10.080
[13] G. Campana (ed.), B. Cimatti (ed.), R. J. Howlett (ed.), R. Setchi (ed.): Sustainable Design and Manufacturing 2017: Selected papers on Sustainable Design and Manufacturing. 1st ed. 2017, Cham, Springer International Publishing; Imprint: Springer, 2017 (Smart Innovation, Systems and Technologies 68) https://doi.org/10.1007/978-3-319-57078-5
[14] C. Prakash, H. K. Kansal, B. S. Pabla, S. Puri, A. Aggarwal: Electric discharge machining – A potential choice for surface modification of metallic implants for orthopedic applications: A review. In: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 230 (2016), Nr. 2, S. 331-353 https://doi.org/10.1177/0954405415579113
[15] A. Mahajan, S. S. Sidhu: Enhancing biocompatibility of Co-Cr alloy implants via electrical discharge process. In: Materials Technology 33 (2018), Nr. 8, S. 524-531 https://doi.org/10.1080/10667857.2018.1475144
[16] A. Mahajan, S. S. Sidhu: Surface modification of metallic biomaterials for enhanced functionality: a review. In: Materials Technology 33 (2018), Nr. 2, S. 93-105 https://doi.org/10.1080/10667857.2017.1377971
[17] S. Jain, V. Parashar: Critical review on the impact of EDM process on biomedical materials. In: Materials and Manufacturing Processes 36 (2021), Nr. 15, S. 1701-1724 https://doi.org/10.1080/10426914.2021.1942907
[18] A. Mahajan, G. Singh, S. Devgan, S. S. Sidhu: EDM performance characteristics and electrochemical corrosion analysis of Co-Cr alloy and duplex stainless steel: A comparative study. In: Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 235 (2021), Nr. 4, S. 812-823 https://doi.org/10.1177/0954408920976739
[19] DIN ISO 5832-12. Chirurgische Implantate – Metallische Werkstoffe. Teil 12: Kobalt-Chrom-Molybdän-Schmiedelegierung (ISO 5832-12:2019).
[20] DIN EN ISO 21920-2:2022-12. Geometrische Produktspezifikation (GPS) – Oberflächenbeschaffenheit: Profile. Teil 2: Begriffe und Kenngrößen für die Oberflächenbeschaffenheit.
[21] DIN EN ISO 6507-1:2024-01. Metallische Werkstoffe – Härteprüfung nach Vickers. Teil 1: Prüfverfahren.
[22] J. X. Zou, T. Grosdidier, K. M. Zhang, B. Gao, S. Z. Hao, C. Dong: Microstructures and phase formations in the surface layer of an AISI D2 steel treated with pulsed electron beam. In: Journal of Alloys and Compounds 434-435 (2007), S. 707-709 https://doi.org/10.1016/j.jallcom.2006.08.280
“”
“”
“”
“”
