41 research outputs found
Tribo-corrosive behavior of additive manufactured parts for orthopaedic applications
No full textBackground: Additive manufacturing (AM) being an integral component of the production offers a wide variety of applications in the production of different components. The medical industry after the introduction of Additive Manufacturing has resulted in several advancements. The production of intricate patient-specific implants is one of such advancements which greatly assist a surgeon during a surgery. Orthopedic implants apart from possessing good mechanical strength are also expected to exhibit good tribological and corrosion behavior. As a result, the development of various orthopaedic implants and tools has become simple with the use of additive manufacturing.
Objectives and Rationale: In the current paper an effort has been made to discuss actual scientific knowledge on the tribo-corrosive behavior of additive manufactured parts for orthopedic applications. Different studies dealing with the mechanisms of lubrication and friction in synovial joints have also been considered. A special focus has also been laid down to study the corrosive effect of implants on the human body. A section dedicated to texturing of orthopedic implants has also been provided. The paper further elaborates the different research challenges and issues related to the use of additive manufacturing for the production of optimized orthopedic implants. Conclusion: The study revealed that additive manufacturing has greatly aided in the manufacture of different orthopaedic implants with enhanced properties. However, a detailed study of the effect of processes like friction, wear, lubrication and corrosion in these implants needs to be done. The performance of these implants in the presence of various synovial fluids also needs to be addressed. However, the lack of more biocompatible ma- terials, scalability and cost issues hinder the widespread use of AM in the different orthopaedic applications
Industrial Computed Tomography for Nondestructive Inspection of Additive Manufactured Parts
No full textPowder bed fusion technology is one of the additive manufacturing
methods that build up near net-shape complex parts from powder form of the
material. Direct Metal Laser Sintering (DMLS) and Selective Laser Sintering
(SLS) are primary powder bed fusion technology methods for metal and polymer
materials respectively. AlSi10Mg is one of the most widely used materials
in DMLS applications while polyamide 2200 (PA) is frequently used in high
quality functional parts production and various prototyping in SLS applications.
By developing technology, AM has begun to provide solution for generating
final products with complex geometries. Dimensional and structural inspection
of the AM parts without any destruction has become important issue in parallel
with the development of the manufacturing technology. Industrial X-Ray
Computed Tomography (X-CT) is one of the promising methods that provide
opportunity to nondestructive inspection of inner structure and porosity of AM
manufactured part. In this study, nondestructive porosity measurement of
DMLS manufactured AlSi10Mg test part and SLS manufactured PA 2200
functional part were applied by X-CT method. Density of manufactured parts
was calculated by measured volume data. Moreover, density of AlSi10Mg part
was defined by Archimedes method and the results were compared with each
other. It can be concluded that X-CT was an effective technique to define
porosity and pore distribution of the AM parts in comparison with Archimedes
porosity measurements
Polimer Esasli Kalça Protezlerinin Yüzeylerinde Sürtünmeye Baglı Olusan Sıcaklık Artışının Belirlenmesi - DETERMINING FRICTIONAL TEMPERATURE RISE ON POLYMER BASED HIP PROSTHESIS SURFACES
No full textAbstract
In this study, it was aimed to determine frictional temperature rise between cross-linked ultra-high molecular weight polyethylene (UHMWPE) acetabular insert and CoCrMo femoral head articulating surfaces. 0,5 mm in diameter dimples were machined on frictional surface of UHMWPE acetabular insert. Effects of these dimples on frictional temperature rise have been investigated. Frictional temperature rise on material surfaces were measured on custom made experimental setup by using real prosthesis samples. The results show that surface dimples served to decrease frictional temperature rise of the surfaces
Modelling and optimization of biotribological testing parameters on frictional heating of vitamin E blended UHMWPE with the help of statistical techniques
No full textIt is known from previous studies that frictional temperature rise on the surfaces of artificial joints could reach high levels that make hazardous effects on surrounding tissue and lubricant around the artificial joint. For enhancement the tribological behavior of the joints, new material combinations have been tried. In this study vitamin E blended ultra-high molecular weight polyethylene (VE-UHMWPE), which is one of the new generation material, was used for acetabular inserts. These inserts were paired with CoCrMo femoral heads. For reduction of the frictional heating, testing parameters and their effects were investigated by using Taguchi method and analysis of variance. The results were analyzed by using Statistical Package for Social Science (SPSS 15.0). Also mathematical model for the temperature rise (Delta T) was developed with the help of statistical techniques
Third-Body Wear Behavior of Orthopedic Biopolymers
No full textThird-body wear of orthopedic materials is very important parameter that affects the service life of artificial joints. Ultra High Molecular Weight Polyethylene (UHMWPE) has been the most preferred acetabular cup material for the past four decades. However wear is the primary problem waiting for to be solved. The wear debris of UHMWPE causes adverse tissue reactions and third-body wear damages which cause implant failure. For enhancement of UHMWPE tribological properties new materials such as vitamin E blended UHMWPE (VE-UHMWPE) have been developed for extending the implants life. Although many researches have been done about tribological behavior of conventional UHMWPE, there are limited numbers of study about third-body wear mechanism of vitamin E blended UHMWPE (VE-UHMWPE). The objective of this study is to determine the effect of PMMA bone cement as third-body particles on wear behavior of conventional UHMWPE and VE-UHMWPE. Pin-on-disc wear tests were applied under 60 N load and 3 hours in ultrapure water lubrication conditions. The results were evaluated for determining wear mechanism of disc materials
Determining frictional behavior of vitamin e blended Uhmwpe
No full textAbstract: Frictional behaviors of articulating surfaces
have been recognized as critical factors affecting their
service life because these behaviors play very important role
on wear of ultrahigh molecular weight polyethylene
(UHMWPE) which causes failure of artificial joint
replacements. The objective of this study is to determine
temperature rise as a function of sliding time and maximum
load for the articulating surfaces of vitamin E blended
UHMWPE acetabular component paired with a cobaltchromium
(CoCrMo) femoral component. Additionally
frictional torque between the bearing surfaces was measured
and friction coefficient was calculated. Frictional
measurements of the joints were carried out on a custom
made hip joint friction simulator. The prostheses were in 28
mm diameter. Applied static loads were changed from 200
N to 1500 N. In flexion-extension plane, a simple harmonic
oscillatory motion between ±24o was applied to the
UHMWPE acetabular component. The period of motion was
1 Hz and the tests were run up to 11000 cycles. Temperature
rise in acetabular and femoral component is recorded with
embedded thermocouples. Also the tests are repeated with
UHMWPE acetabular component. The results are compared
in terms of UHMWPE and vitamin E blended UHMWPE
Optimization of Frictional Heating Parameters of Artificial Joint Materials by Taguchi Approach
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