scholarly journals Novel Polishing Media for Finishing Hip Joint Implants

2021 ◽  
Author(s):  
Yahya Choopani ◽  
Mohsen Khajehzadeh ◽  
Mohammad Reza Razfar
Keyword(s):  
Surface Roughness ◽  
Femoral Head ◽  
Hip Joint ◽  
Substantial Reduction ◽  
Sisal Fiber ◽  
Future Application ◽  
Finishing Process ◽  
Joint Implants ◽  
Optimized Conditions ◽  
Influential Parameters

Abstract Automating the finishing process of the femoral head in hip joint implants is one of the greatest concerns in industrial and academic societies. To achieve this goal, first, a negative replica is developed for the femoral head in the abrasive flow finishing (AFF) process. Then, a novel polishing media by combining the viscoelastic carrier and coarse sisal fiber is proposed for finishing. Finally, the performance of the finishing procedure through the proposed polishing media is assessed experimentally by evaluating the influential parameters of the AFF process on the surface roughness of the femoral head, which is made from ASTM F138 (SS 316L). Experimental results prove the effectiveness of the proposed polishing media in negative replica for finishing of femoral head owing to the severe mechanical disintegration. This is validated with the substantial reduction of surface roughness in the femoral head from 134.6 nm to 36.96 nm. Furthermore, AFM results confirm the improved surface topography parameters of Ra, Rq, and Rt in the femoral head under optimized conditions by 72.54%, 70.50%, and 64.79%, respectively. Generally, it can be said that promising results for future application of the polishing media in the AFF process are obtained.

Optimal parameters of abrasive flow finishing for hip joint implants

2021 ◽  
pp. 095440542199561
Author(s):  
Yahya Choopani ◽  
Mohsen Khajehzadeh ◽  
Mohammad Reza Razfar
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Femoral Head ◽  
Hip Joint ◽  
Spherical Shape ◽  
Shape Deviation ◽  
Head Surface ◽  
Joint Implants ◽  
Finishing Processes ◽  
Abrasive Flow Finishing

Total hip arthroplasty (THA) is one of the most well-known orthopedic surgeries in the world which involves the substitution of the natural hip joint by prostheses. In this process, the surface roughness of the femoral head plays a pivotal role in the performance of hip joint implants. In this regard, the nano-finishing of the femoral head of the hip joint implants to achieve a uniform surface roughness with the lowest standard deviation is a major challenge in the conventional and advanced finishing processes. In the present study, the inverse replica fixture technique was used for automatic finishing in the abrasive flow finishing (AFF) process. For this aim, an experimental setup of the AFF process was designed and fabricated. After the tests, experimental data were modeled and optimized to achieve the minimum surface roughness in the ASTM F138 (SS 316L) femoral head of the hip joint through the use of response surface methodology (RSM). The results confirmed uniform surface roughness up to the range of 0.0203 µm with a minimum standard deviation of 0.00224 for the femoral head. Moreover, the spherical shape deviation of the femoral head was achieved in the range of 7 µm. The RSM results showed a 99.71% improvement in the femoral head surface roughness (0.0007) µm under the optimized condition involving the extrusion pressure of 9.10 MPa, the number of finishing cycles of 95, and SiC abrasive mesh number of 1000.

Nonsphericity of Bearing Geometry and Lubrication in Hip Joint Implants

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
F. C. Wang ◽  
S. X. Zhao ◽  
A. Félix Quiñonez ◽  
H. Xu ◽  
X. S. Mei ◽  
...  
Keyword(s):  
Femoral Head ◽  
Hip Joint ◽  
Spherical Surface ◽  
Elastohydrodynamic Lubrication ◽  
Acetabular Cup ◽  
Surface Geometry ◽  
Spherical Coordinate ◽  
Transient Conditions ◽  
Convolution Model ◽  
Joint Implants

A general elastohydrodynamic lubrication model was developed to consider the nonsphericity of the bearing geometry in hip joint implants, both under the steady and transient conditions. The articulation between the femoral head and the acetabular cup was represented by a nominal ball-in-socket configuration. The nonsphericity was introduced on the acetabular cup and femoral head bearing surfaces in the form of an ellipsoidal surface represented by variations of the radii of curvature given by the three semi-axis lengths of the ellipsoid with regard to a nominal spherical surface. An appropriate spherical coordinate system and solution domain discretization were used to facilitate the numerical simulations. Both the equivalent discrete spherical convolution model and the corresponding spherical fast Fourier transform technique were used to evaluate the elastic deformation of either the spherical or nonspherical bearing surfaces. A fixed-tracked method was also developed to simulate the complex morphology introduced by moving the interface of the nonspherical bearing surfaces. The general methodology for the nonspherical bearing was first applied to investigate the steady-state elastohydrodynamic lubrication of an ellipsoidal cup articulating against a spherical head in a typical metal-on-metal hip joint implant. Subsequently, the problem of an ellipsoidal head articulating against a spherical cup was considered under the transient conditions. The significance of nonsphericity of bearing geometry in hip joint implants due to manufacturing, designing, and wear was discussed. The results obtained showed that the effect of a nonspherical bearing surface geometry on elastohydrodynamic lubrication was dependent on the orientation, the magnitude, and the deviation direction of the nonsphericity. A well-controlled nonsphericity was seen to be beneficial for improving the lubrication.

Modeling of surface roughness in a novel magnetorheological gear profile finishing process

2020 ◽  
pp. 095440622097826
Author(s):  
Ravi Datt Yadav ◽  
Anant Kumar Singh ◽  
Kunal Arora
Keyword(s):  
Surface Roughness ◽  
Gear Tooth ◽  
Surface Characteristics ◽  
Spur Gear ◽  
Tooth Profile ◽  
Tooth Surface ◽  
Magnetic Flux Density ◽  
Element Analysis ◽  
Finishing Process ◽  
Gear Profile

Fine finishing of spur gears reduces the vibrations and noise and upsurges the service life of two mating gears. A new magnetorheological gear profile finishing (MRGPF) process is utilized for the fine finishing of spur gear teeth profile surfaces. In the present study, the development of a theoretical mathematical model for the prediction of change in surface roughness during the MRGPF process is done. The present MRGPF is a controllable process with the magnitude of the magnetic field, therefore, the effect of magnetic flux density (MFD) on the gear tooth profile has been analyzed using an analytical approach. Theoretically calculated MFD is validated experimentally and with the finite element analysis. To understand the finishing process mechanism, the different forces acting on the gear surface has been investigated. For the validation of the present roughness model, three sets of finishing cycle experimentations have been performed on the spur gear profile by the MRGPF process. The surface roughness of the spur gear tooth surface after experimentation was measured using Mitutoyo SJ-400 surftest and is equated with the values of theoretically calculated surface roughness. The results show the close agreement which ranges from −7.69% to 2.85% for the same number of finishing cycles. To study the surface characteristics of the finished spur gear tooth profile surface, scanning electron microscopy is used. The present developed theoretical model for surface roughness during the MRGPF process predicts the finishing performance with cycle time, improvement in the surface quality, and functional application of the gears.

Experimental investigation into polishing of monocrystalline silicon wafer using double-disc chemical assisted magnetorheological finishing process

2021 ◽  
pp. 095440622098384
Author(s):  
Mayank Srivastava ◽  
Pulak M Pandey
Keyword(s):  
Surface Roughness ◽  
Silicon Wafer ◽  
Flow Rate ◽  
Silicon Wafers ◽  
Monocrystalline Silicon ◽  
Slurry Flow ◽  
Magnetorheological Finishing ◽  
Finishing Process ◽  
Process Factors ◽  
Slurry Flow Rate

In the present work, a novel hybrid finishing process that combines the two preferred methods in industries, namely, chemical-mechanical polishing (CMP) and magneto-rheological finishing (MRF), has been used to polish monocrystalline silicon wafers. The experiments were carried out on an indigenously developed double-disc chemical assisted magnetorheological finishing (DDCAMRF) experimental setup. The central composite design (CCD) was used to plan the experiments in order to estimate the effect of various process factors, namely polishing speed, slurry flow rate, percentage CIP concentration, and working gap on the surface roughness ([Formula: see text]) by DDCAMRF process. The analysis of variance was carried out to determine and analyze the contribution of significant factors affecting the surface roughness of polished silicon wafer. The statistical investigation revealed that percentage CIP concentration with a contribution of 30.6% has the maximum influence on the process performance followed by working gap (21.4%), slurry flow rate (14.4%), and polishing speed (1.65%). The surface roughness of polished silicon wafers was measured by the 3 D optical profilometer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were carried out to understand the surface morphology of polished silicon wafer. It was found that the surface roughness of silicon wafer improved with the increase in polishing speed and slurry flow rate, whereas it was deteriorated with the increase in percentage CIP concentration and working gap.

scholarly journals Towards the prediction of surface roughness induced by the belt finishing process: influence of the workmaterial on the roughness reduction rate

Procedia CIRP ◽  
2020 ◽  
Vol 87 ◽  
pp. 210-215
Author(s):  
F. Cabanettes ◽  
O. Cherguy ◽  
C. Courbon ◽  
A. Giovenco ◽  
S. Han ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Reduction Rate ◽  
Finishing Process

scholarly journals Microvascular Density of Rapidly Destructive Arthropathy of the Hip Joint

2005 ◽  
Vol 13 (1) ◽  
pp. 40-45 ◽  
Author(s):  
T Yamakawa ◽  
A Sudo ◽  
M Tanaka ◽  
A Uchida
Keyword(s):  
Femoral Head ◽  
Hip Joint ◽  
Joint Destruction ◽  
Bone Destruction ◽  
Microvascular Density ◽  
Blood Capillaries ◽  
Secondary Osteoarthritis ◽  
Femoral Heads ◽  
Formalin Fixed Paraffin Embedded ◽  
Destructive Arthropathy

Purpose. To assess the vascularity of the femoral head and determine how it is related to the destruction of the arthritic hip joint. The process of destructive arthropathy in arthritic hip joints is variable. Some patients with osteoarthritis of the hip have rapidly progressive destructive changes resulting in the disappearance of the femoral head. Method. Six femoral heads from patients diagnosed with rapidly destructive arthropathy and 6 femoral heads from patients with secondary osteoarthritis caused by acetabular dysplasia were analysed to reveal the association between blood capillaries and osteoclasts. The von Willebrand Factor immunostaining and counterstaining with Mayer's haematoxylin were used to label the microvessels and osteoclasts in formalin-fixed, paraffin-embedded specimens of femoral heads. The numbers of immunostained microvessels and osteoclasts in selected regions were counted. Result. The microvascular density of the bone surfaces of rapidly progressive arthritic hips was hypervascular. Osteoclasts were also found in increased numbers on the bone surfaces of rapidly progressive arthritic hips. The higher microvascular density coincided with extensive bone destruction and with the increased osteoclast count. Conclusion. These findings suggested that hypervascularity of the granulation in the femoral head may be associated with bone and joint destruction.

A method for visualizing the dorsal acetabular rim and the coverage of the femoral head

2001 ◽  
Vol 14 (03) ◽  
pp. 151-155 ◽  
Author(s):  
J. Hoskinson ◽  
W. C. Renberg
Keyword(s):  
Femoral Head ◽  
Hip Joint ◽  
Prognostic Value ◽  
Degenerative Change ◽  
Femoral Shaft ◽  
Normal Activity ◽  
Degenerative Joint Disease ◽  
Joint Disease ◽  
Anatomical Landmarks ◽  
Acetabular Rim

SummaryThe authors describe a new technique to visualize the dorsal acetabular rim and the coverage of the femoral head in the nonsedated dog. The technique involves using an overhead beam, directed at an angle tangential to the dorsal rim of the acetabulum, with a film positioned caudal to the standing dog. Anatomical landmarks that can routinely be identified include: the ilial crest, ilial shaft, ischial tuberosity, acetabulum, acetabular rim (particularly the dorsocaudal component), femoral head, greater trochanter, femoral neck, femoral shaft, rectum and the tail. Because the animal is standing and is not sedated, the technique may have additional value as a means of evaluating subluxation of the hip joint. It maintains a posture as close as possible to that experienced by the animal in normal activity. If the technique has prognostic value in that regard, more investigation is needed, but it is useful in itself as a technique to visualize the area of the acetabulum.A new radiographic technique to evaluate the canine hip joint is described. The view involves tangential projection of the acetabulum in the standing, awake dog. Nineteen dogs have been radiographed to develop the technique and the method has been found to be technically simple and consistent. It allows examination of the dorsal acetabular rim and may help examine the amount of subluxation of the hip as well as the presence of any degenerative joint disease. The authors advocate additional study to determine the technique’s prognostic value in predicting degenerative change associated with hip dysplasia.

Tribological property of the cobalt—chromium femoral head with different regions of wear in total hip arthroplasty

2009 ◽  
Vol 224 (4) ◽  
pp. 541-549 ◽  
Author(s):  
C-T Duong ◽  
J-S Nam ◽  
E-M Seo ◽  
B P Patro ◽  
J-D Chang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Femoral Head ◽  
Total Hip Arthroplasty ◽  
Tribological Properties ◽  
Hip Arthroplasty ◽  
Frictional Coefficient ◽  
Cobalt Chromium ◽  
Bearing Materials ◽  
Frictional Coefficients ◽  
Wear Region

The tribological properties of engineering and biological materials have been investigated at microscale levels through the calculation of the surface roughness and frictional coefficient using atomic force microscopy (AFM). Although a number of previous studies have reported the frictional coefficients of diverse bearing materials in total hip arthroplasty (THA), the relationship between the surface roughness and frictional coefficient of bearing materials of THA have not been reported, and furthermore, the tribological properties for different wear regions of a cobalt-chromium (Co—Cr) femoral head have not been well identified. Therefore, the objective of this study is to investigate the relationships between the surface roughness, frictional coefficient, and hardness for both the main-wear and the least-wear regions of a Co—Cr femoral head 10 years after THA. The average Vickers hardness of the Co—Cr femoral head was 380.7 ± 11.3 HV. With the scanned area of 25 μm×25 μm through AFM, the frictional coefficients of the main-wear and the least-wear regions were 0.229 ± 0.054 and 0.243 ± 0.059, respectively, and showed no statistical differences between these two regions ( p = 0.449). However, differences in the surface roughness ( Rq) between the main-wear region ( Rq = 96.5 ± 26.2 nm) and the least-wear region ( Rq = 17.7 ± 4.2 nm) were statistically significant ( p<0.0001). The results of the current study suggest that the frictional property of the Co—Cr femoral head is not significantly correlated with its surface roughness, and also provide guidelines for improving the surface characteristics of metallic implant materials.

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