Purpose
With technology advances, metallic implants claim to improve the quality and durability of human life. In the recent decade, Ti-6Al-4V biomaterial has been additively manufactured via ...selective laser melting (SLM) for orthopedic applications. This paper aims to provide state-of-the-art on mechanobiology of these fabricated components.
Design/methodology/approach
A literature review has been done to explore the potential of SLM fabricated Ti-6Al-4V porous lattice structures (LS) as bone substitutes. The emphasize was on the effect of process parameters and porosity on mechanical and biological properties. The papers published since 2007 were considered here. The keywords used to search were porous Ti-6Al-4V, additive manufacturing, metal three-dimensional printing, osseointegration, porous LS, SLM, in vitro and in vivo.
Findings
The properties of SLM porous biomaterials were compared with different human bones, and bulk SLM fabricated Ti-6Al-4V structures. The comparison was also made between LS with different unit cells to find out whether there is any particular design that can mimic the human bone functionality and enhance osseointegration.
Originality/value
The implant porosity plays a crucial role in mechanical and biological characteristics that relies on the optimum controlled process variables and design attributes. It was also indicated that although the mechanical strength (compressive and fatigue) of porous LS is not mostly close to natural cortical bone, elastic modulus can be adjusted to match that of cortical or cancellous bone. Porous Ti-6Al-4V provide favorable bone formation. However, the effect of design variables on biological behavior cannot be fully conclusive as few studies have been dedicated to this.
Porous Lattice Structure (PLS) scaffolds have shown potential applications in the biomedical domain. These implants’ structural designs can attain compatibility mechanobiologically, thereby avoiding ...challenges related to the stress shielding effect. Different unit cell structures have been explored with limited work on the fabrication and characterization of titanium-based PLS with cubic unit cell structures. Hence, in the present paper, Ti6Al4V (Ti64) cubic PLS scaffolds were analysed by finite element (FE) analysis and fabricated using selective laser melting (SLM) technique. PLS of the rectangular shape of width 10 mm and height 15 mm (ISO: 13314) with an average pore size of 600–1000 μm and structure porosity percentage of 40–70 were obtained. It has been found that the maximum ultimate compressive strength was found to be 119 MPa of PLS with a pore size of 600 μm and an overall relative density (RD) of 57%. Additionally, the structure’s failure begins from the micro-porosity formed during the fabrication process due to the improper melting along a plane inclined at 45 degree.
The aim of the study is to predict the optimal machining conditions in electrical discharge machining (EDM) of particulate-reinforced metal matrix composites (30 vol% SiC/A359). Three independent ...machining variables viz: current, pulse-on time and pulse-off time are investigated to encompass the EDM performance in terms of induced residual stresses on the machined surface, tool wear rate and material removal rate. The L9 orthogonal array is employed as an experimental plan. The responses results are globally optimized using desirability function approach and lexicographic goal programming (LGP) approach to predict the ideal parametric combinations for the machining of selected composite material. It was observed that both the techniques give a nearly identical optimum solution, i.e. the optimal predicted process parameters value deviation varies from 0 to 1.82%. However, LGP technique is the simplest priority-based approach that can be utilized more efficiently in the complex decision-making conditions. Confirmation test on the predicted optimal results is executed experimentally, and the value of confirmation error is found to be satisfactory.
The current study develops a numerical model to investigate the nanoindentation behavior of heat-affected zones (HAZ) on glass material produced via the electrochemical spark machining (ECSM) method. ...Initially, microchannels were created using the ECSM method on soda–lime glass. Following that, a nanoindentation test was conducted to quantify the Young’s modulus and hardness of the glass sample. After that, a numerical model based on finite elements was created to characterize the changes in mechanical characteristics of HAZ. According to the findings, increasing the electrolyte concentration from 10 to 30% increases the intensity of electrochemical discharges, and thereby decreases the hardness of the work material by 16.29 to 30.58% compared to unmachined glass. The results obtained from the simulation are in close agreement with the experimental values. The maximum error obtained between simulation and experimental results is only 4.18%.
Slippery flooring often leads to unintentional slips and falls, which results in traumatic injuries. To reduce slipping risks, adequate traction at the shoe and flooring contact is essential. In ...addition, viscous slippery contaminants like water or oil reduce a floor’s traction performance and increase slipping hazards. In this work, the effect of commonly available protective floor coatings on the traction performance of safety-labelled shoes was extensively studied. The study included three floor coatings, namely acid-based etchant coating, epoxy floor paint, and polyurethane, which were tested across five safety shoes. The coated floorings were tested using a robotic slip-testing device in dry and in the presence of water and machine oil—as separate contaminants. The application of floor coatings produced varying surface roughness for the flooring. Significant traction was generated by the etchant coating for the dry flooring, epoxy coating for the wet flooring, and polyurethane coating for all flooring conditions. A comparison of uncoated and coated floorings showed a high effectiveness of generating traction with epoxy coating on wet flooring and polyurethane coating on both wet and oily conditions. The study results are novel and are anticipated to provide valuable guidelines for the selection of slip-resistant coatings for different slippery floorings, and to reduce risks related to slips and falls.
This study investigates the effect of electrolytic plasma processing on the degree of defective layer removal from a damaged layer obtained after manufacturing operations. Electrical discharge ...machining (EDM) is widely accepted in modern industries for product development. However, these products may have undesirable surface defects that may require secondary operations. This work aims to study the die-sinking EDM of steel components followed by the application of plasma electrolytic polishing (PeP) to enhance the surface properties. The results showed that the decrease in the roughness of the EDMed part after PeP was 80.97%. The combined process of EDM and subsequent PeP makes it possible to obtain the desired surface finish and mechanical properties. In the case of finishing EDM processing and turning, followed by PeP processing, the fatigue life is enhanced without failure up to 10
cycles. However, the application of this combined method (EDM + PeP) requires further research to ensure consistent removal of the unwanted defective layer.
Surface modification trends in biomaterials are focused on addressing the rise in challenges and complications in bone-related medical treatments. The review framework is based on the significant ...physicochemical modification challenges performed over the last five decades for achieving favourable conditions. With the increase in skills acquired regarding molecular and cell biology, surface engineering represents a significant impact on the cell adhesion and regeneration. This article highlights the outstanding techniques having the potential to modify the surface for improving overall functionality and lifespan of the implants. The paper also incorporates electrical discharge machining process, a possible futuristic surface modification method that is known by its versatile characteristics of high precision and ability for altering the surface topography.
•Surface modification techniques executed on biomaterials are reviewed.•Coatings of various type of bioactive material are addressed.•EDM treatment of biomaterials as a futuristic alternative.
This paper presents an analysis and theoretical model for assessing the quality and accuracy of wire-cut electro-discharge machining (WEDM) of products made from novel heat-resistant nickel alloys ...such as CrNi56KVMTYB. It is observed that WEDM processing of Ni alloy led to high surface roughness for the thick specimens, and electrical parameters such as pulse duration for the selected range depict an insignificant role in the value of surface roughness. On the other hand, the cut width of the machined surface decreases as the pulse duration increases, while the cut width is elevated for thick workpieces. Secondary discharges developed in WEDM have negative effects that cause sludge adhering and deterioration in the quality and productivity of processing. The regression model is developed to predict the surface roughness and cut width of machined surfaces, which holds significant importance in modern engineering. The workpiece is examined for surface integrity and material deposition. It is observed that an increase in the height of the specimen leads to the occurrence of secondary discharges, which in turn results in the formation of cracks on the surfaces of high-temperature nickel alloys. These cracks have a detrimental effect on the performance of critical products made from next-generation heat-resistant nickel alloys.
In the present work, the effect of tool surface roughness on energy channelization behavior was analyzed during the fabrication of micro holes by an electrochemical spark machining (ECSM) process. In ...this study, rough tools were fabricated by a rotary mode multi tip electric discharge machining (RM-MT-EDM) process. The electrical characterization was also carried out to investigate the electric field intensity over the surface of tool electrode, and it was found that the use of rough tools improves the electric field intensity by 265.54% in comparison to the smooth tool electrodes. The use of rough tools in the ECSM process forms thin and stable gas film over the tool electrode, and as a result the rough tools produced high frequency spark discharges. Energy channelization index and specific energy were considered as response characteristics. The use of rough tools improves energy channelization index by 248.40%, and the specific energy is reduced by 143.263%. The material removal mechanisms for both of the processes (RM-MT-EDM and ECSM process) have also been presented through illustrations.
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•CR4 cold rolled steel sheet has been air bent.•XRD peak broadening analysis has been conducted for different samples.•CR4 steel sheet has compressive lattice strain, in all the three ...orientation.•Lattice strain increases after air bending across thickness.•Results about lattice strain are highly useful for industries.
In this study, the effect of orientation and bending has been investigated on CR4 steel for lattice constant, crystallite size and lattice strain. The one mm thick sheet of CR4 steel was bent through air-bending. The samples were prepared by using wire electric discharge machining (WEDM) followed by polishing for X-ray diffraction study. The peaks were analysed using QualX 2.1 software and lattice constant was analysed using Bragg’s law and lattice strain using Williamson-Hall’s method. Result shows, lattice constant is smallest on rolled face and after bending it increases along thickness. Whereas, the lattice strain is compressive in nature for all three orientations. However, for 0°orientation lattice strain (0.5%) is more across the thickness as compared to 90°orientation lattice strain (0.34%). Crystallite size was analysed by Scherrer’s method and Williamson-Hall’s method. Williamson-Hall’s crystallite size is observed to be smaller than Scherrer’s crystallite size. Further, crystallite size is observed to be the smallest on the rolled face. Moreover, after bending force application, enhancement in the lattice strain is observed while the size of the crystallite is reduced noticeably.
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