Powder Mixed Electric Discharge Machining: An Innovative Surface Modification Technique to Enhance Fatigue Performance and Bioactivity of β-Ti Implant for Orthopedics Application

2016 ◽  
Vol 16 (4) ◽  
Author(s):  
Chander Prakash ◽  
H. K. Kansal ◽  
B. S. Pabla ◽  
Sanjeev Puri
Keyword(s):  
Surface Roughness ◽  
Surface Modification ◽  
Electric Discharge ◽  
Fatigue Behavior ◽  
Research Work ◽  
Fatigue Performance ◽  
Electric Discharge Machining ◽  
Local Factor ◽  
Modification Technique ◽  
Fatigue Endurance

The development of surface modification technique has been the subject of the studies regarding the fatigue performance and biological characterization of the modified layers. In the present research work, powder mixed electric discharge machining (PMEDM) a novel nonconventional machining technique has been proposed for surface modification of β-Ti implant for orthopedics application. The surface topography and morphology like roughness, surface cracks, and recast layer thickness of each of the machined specimens were investigated using Mitutoyo surface roughness tester and field-emission scanning electron microscopy (FE-SEM), respectively. This study aims to investigate the effect of surface characteristics of PMEDM process on the fatigue performance and bioactivity of β-Ti implants and moreover a comparative analysis is made on the fatigue performance and biological activity of specimens machined with presently used machining methods like electric discharge machining (EDM) and mechanical polishing. The high cycle fatigue (HCF) performance of polished specimens was superior and had no adverse effect of microstructure on fatigue endurance. As expected, the fatigue behavior of β-Ti implant-based alloy, after undergoing EDM treatment, is poorly observed due to the microrough surface. The fatigue performance is dependent on microstructure and surface roughness of the specimens. Subsequent PMEDM process significantly improves the fatigue endurance of β-Ti implant-based alloy specimens. PMEDMed surface with micro-, sub-micro-, and nano-structured topography exhibited excellent bioactivity and improved biocompatibility. PMEDMed surface enabled better adhesion and growth of MG-63 when compared with the polished and EDMed substrate. Furthermore, the differentiation results indicated that a combination of nanoscale featured submicrorough PMEDMed surface promotes various osteoblast differentiation activities like alkaline phosphatase (ALP) activity, osteocalcin production, the local factor osteoprotegerin, which inhibits osteoclastogenesis.

Optimization and Prediction of Machining Responses Using Response Surface Methodology and Adaptive Neural Network by Wire Electric Discharge Machining of Alloy-X

2021 ◽  
Vol 1026 ◽  
pp. 28-38
Author(s):  
I. Vishal Manoj ◽  
S. Narendranath ◽  
Alokesh Pramanik
Keyword(s):  
Neural Network ◽  
Surface Roughness ◽  
Artificial Neural Network ◽  
Response Surface ◽  
Electric Discharge ◽  
Cutting Speed ◽  
Electric Discharge Machining ◽  
Surface Method ◽  
Wire Electric Discharge Machining ◽  
Pulse On Time

Wire electric discharge machining non-contact machining process based on spark erosion technique. It can machine difficult-to-cut materials with excellent precision. In this paper Alloy-X, a nickel-based superalloy was machined at different machining parameters. Input parameters like pulse on time, pulse off time, servo voltage and wire feed were employed for the machining. Response parameters like cutting speed and surface roughness were analyzed from the L25 orthogonal experiments. It was noted that the pulse on time and servo voltage were the most influential parameters. Both cutting speed and surface roughness increased on increase in pulse on time and decrease in servo voltage. Grey relation analysis was performed to get the optimal parametric setting. Response surface method and artificial neural network predictors were used in the prediction of cutting speed and surface roughness. It was found that among the two predictors artificial neural network was accurate than response surface method.

Effects of Machining Fluid on Electric Discharge Machining of SiC Ingot

2014 ◽  
Vol 778-780 ◽  
pp. 767-770 ◽  
Author(s):  
Norimasa Yamamoto ◽  
Satarou Yamaguchi ◽  
Tomohisa Kato
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Ion Exchange ◽  
Electric Discharge ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Electric Discharge Machining ◽  
The Wire ◽  
Characteristic Features ◽  
First Time

Recently, ingots of silicon carbide have been adapted to be sliced by the wire-cut electrical discharge machining. Fast slicing, and the reduction in the loss are important for slicing of the wafer. In this paper, characteristic features of the electric discharge machining in the ion-exchange water and the fluorine-based fluid were compared for these improvement. The discharge was caused by a pulse voltage applied to a ingot of silicon carbide and the wire in machining fluid, and the slicing was proceeded. As a result, improvement of surface roughness and kerf loss was confirmed, for the first time. In addition, the improving methods for fast slicing were considered.

Structural Changes in TiO2 Films Formed by Anodizing of Electro-Polished Titanium

2016 ◽  
Vol 869 ◽  
pp. 689-692
Author(s):  
Patricia López Díaz ◽  
Marinalda Claudete Pereira ◽  
Eduardo Norberto Codaro ◽  
Heloisa Andréa Acciari
Keyword(s):  
Surface Roughness ◽  
Raman Spectroscopy ◽  
Surface Modification ◽  
Direct Current ◽  
Structural Changes ◽  
Polarized Light ◽  
Applied Potential ◽  
Granular Microstructure ◽  
Crystalline Films ◽  
Modification Technique

Anodizing is a surface modification technique that is applied to growing oxide films on Ti to accelerate the osseointegration of an implant. Besides the surface roughness, the crystalline structure of these films can affect its performance as a biomaterial. For this reason, this technique has been refined to produce crystalline films without requiring heat treatments. For this purpose, TiO2 films were grown on Ti (grade 2) by anodizing with direct current at different potentials. Images obtained by optical microscopy with polarized light revealed a granular microstructure in various colors, as consequence of different crystalline orientations of the grains and films thickness. Raman spectroscopy showed that the films crystallinity is affected by variations in the applied potential and anodizing time.

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