I'm trying to machine orthopedic implants using EDM to satisfy the surface texture requirements. I would like to know the roughness range in microns required for such a surface. Also, if there is any other surface quality which needs to be controlled, kindly mention that too.
I agree with Prof. Ciftdemir that a "rougher" surface should be generated. From medical point of view it would be desirable if special materials for bone-ingrowth could be implemented in the surface. Is about us not yet succeeded to the satisfaction (EDM).
Be observed when roughness contemplation must that altered relations between the mean roughness and the roughness maxmalen made by the specific removal process the EDM, compared to mechanical machining methods.
More definitions are dependent on the material used (Ti or Steel) and the application.
I feel Prof H.P Schulze has given right suggetion regarding material.Titanium is the best, however costly. or Stainless steel. The surface roughness value of 2-5 microns Ra may suit the purpose and it can be easily achieved by EDM by controlling the input parameters like machining current and spark on time.
Dear Sundaresan, Read my papers:
1. Chander Prakash, H.K. Kansal, B.S. Pabla, Sanjeev Puri and Aditya Aggarwal, “Electric discharge machining – A potential choice for surface modification of metallic implants for orthopedic applications: A review”, Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 230(2), 231-253, 2016.
2. Chander Prakash, H.K. Kansal, B.S. Pabla, and Sanjeev Puri, “Processing and Characterization of Novel Biomimetic Nanoporous Bioceramic Surface on β-Ti Implant by Powder Mixed Electric Discharge Machining”, Journal of Materials Engineering and Performance, 24:3622–3633, 2015.
3. Chander Prakash, H.K. Kansal, B.S. Pabla, and Sanjeev Puri, “Experimental Investigations in Powder Mixed Electrical Discharge Machining of Ti-35Nb-7Ta-5Zr β-Ti Alloy”, Material and Manufacturing Process, accepted in April 2016, 10.1080/10426914.2016.1198018 (In-Press).
4. Chander Prakash, H.K. Kansal, B.S. Pabla, and Sanjeev Puri, “Effect of Surface Nano-Porosities Fabricated by Powder Mixed Electric Discharge Machining on Bone-Implant Interface: An Experimental and Finite Element Study” Nanoscience and Nanotechnology Letters, Vol. 8 (10), 815-826, 2016, Doi:10.1166/nnl.2016.2255.
5. Chander Prakash, H.K. Kansal, B.S. Pabla, and Sanjeev Puri, “Multi-objective optimization of powder mixed electric discharge machining parameters for fabrication of biocompatible layer on β-Ti alloy using NSGA-II coupled with Taguchi based response surface methodology”, Journal of Mechanical Science and Technology, 30 (9), 4195~4204, 2016.
6. Chander Prakash, H.K. Kansal, B.S. Pabla, and Sanjeev Puri, “Powder Mixed Electric Discharge Machining an Innovative Surface Modification Technique to Enhance Fatigue Performance and Bioactivity of β-Ti Implant for Orthopaedics Application”, Journal of Computing and Information Science in Engineering, accepted with minor revision,2016, Doi:10.1115/1.4033901 (In-Press).
7. Chander Prakash, H.K. Kansal, B.S. Pabla, and Sanjeev Puri, “Potential of Powder Mixed Electric Discharge Machining to Enhance the Wear and Tribological performance of β-Ti Implant for Orthopedic Applications”, Journal of Nanoengineering and Nanomanufacturing, 5(4), 261-269, 2015.
For bone growth, its less than 100 nm. And for parts where relative movement is there, its below 10 nm and preferably below 1 nm. By EDM, it will be very rough. Post processing technique has to be employed viz. nanofinishing.
Hello Tribeni,
How do you come to these values? In principle, you can also achieve a glossy surface with EDM. The question is only, I really want it. In areas where the implant is to grow with the bone, rougher surfaces are more favorable. It is best if materials can be integrated into the surface with the processing. In the area of movement, of course, fine surface structures are sensible, but not too smooth, because in the "friction area" media should be able to position stably, which improve the friction behavior and prevent "jamming". In technical systems, mini-channels are then introduced which lead these lubricants to the moving surfaces.
A fine finish on surface eradicates the possibility of chipping due to contact between micro-nano peaks. @Schulze sir, literature shows that knee implants are being nano finished with a very low Ra as possible. And the concept of nano texturing at locations where bone growth is required is concept of surface energy. With increase in surface energy of textures, the bone growth will take place rapidly at those areas.
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