The first successful direct 3D printing, or additive manufacturing (AM), of heat-cured silicone meniscal implants, using biocompatible and bio-implantable silicone resins is reported. Silicone implants have conventionally been manufactured by indirect silicone casting and molding methods which are expensive and time-consuming. A novel custom-made heat-curing extrusion-based silicone 3D printer which is capable of directly 3D printing medical silicone implants is introduced. The rheological study of silicone resins and the optimization of critical process parameters are described in detail. The surface and cross-sectional morphologies of the printed silicone meniscus implant were also included. A time-lapsed simulation study of the heated silicone resin within the nozzle using computational fluid dynamics (CFD) was done and the results obtained closely resembled real time 3D printing. Solidworks one-convection model simulation, when compared to the on-off model, more closely correlated with the actual probed temperature. Finally, comparative mechanical study between 3D printed and heat-molded meniscus is conducted. The novel 3D printing process opens up the opportunities for rapid 3D printing of various customizable medical silicone implants and devices for patients and fills the current gap in the additive manufacturing industry.

https://www.mdpi.com/2073-4360/12/5/1031/pdf

3D Direct Printing of Silicone Meniscus Implant Using a Novel Heat-Cured Extrusion-Based Printer.

In recent years, Aluminium Alloy 7075 plays a vital role in the manufacturing of aircraft wing and fuselage skin due to its light weight and specific strength characteristic behavior. The component...

Assessment of erosion rate on AA7075 based surface hybrid composites fabricated through friction stir processing by taguchi optimization approach

The present study aimed to improve the micro-hardness and wear properties of AA2014 aluminum alloy. Surface composite of AA2014 was produced using Al2O3 as reinforcement by friction stir processing (FSP) technique. FSP was performed by using a constant traverse speed of 40 mm/min and two rotating speeds of 1000 and 1400 rpm. After FSP, the average grain size of AA2014 was reduced from 21.9 µm in base material to 9.2 µm in FSP with a rotating speed of 1000 rpm and 3.8 µm in FSP with rotating speed of 1400 rpm. Optical microscopy showed that the Al2O3 reinforcement particles were distributed homogeneously in AA2014 after FSP. The micro-hardness test showed that the hardness property in AA2014/Al2O3 surface composite was improved after FSP and was increased with an increase in rotating speed. The micro-hardness was improved by 30% after FSP. The wear test revealed that both the wear performance and coefficient of friction (COF) were improved after FSP. The COF was improved from 0.27461 in base material to 0.22570 in FSPed samples. Surface roughness test showed that the sample with more micro-hardness showed better surface roughness as compared to the other samples.

/pdf/micro-hardness-and-wear-behavior-of-aa2014-al2o3-surface-50d5a2wmys.pdf

Micro-hardness and wear behavior of AA2014/Al2O3 surface composite produced by friction stir processing

Investigation on the thermal behaviour of AZ31B/waste eggshell surface composites produced by friction stir processing

The ultimate objective is to evaluate the efficacy of three-dimensional printers (3DP) for manufacturing a rear spoiler for radio-controlled (RC) racing cars. This research work focuses on...

3D Printing of automobile spoilers using MCDM techniques

Recently, cylinder liners of automotive and aircraft engines are encountered severe wear due to piston slap occurred by the repeated sliding stroke of piston. This research focuses on providing an ...

Influence of secondary phase particles Al2O3/SiC on the microstructure and tribological characteristics of AA7075-based surface hybrid composites tailored using friction stir processing:

Investigations on micro hardness, electrical and thermal conductivity of AA7075 surface hybrid composites produced through friction stir processing

In this work, the MAF set-up is fixed on a vertical milling machine, and experiments are performed for optimizing the process parameters using central composite design (CCD) based on respo...

Process parameter optimization for the magnetic abrasive finishing of SS310s steel

Investigations on microstructure, thermo-mechanical and tribological behavior of graphene oxide reinforced AA7075 surface composites developed via friction stir processing

The novel friction stir technology is adopted in modern automotive industries to meet the desired properties like hardness, impact toughness and tribological behaviour over the conventional techniques like stir casting, compo casting, squeeze casting, electroplating and infiltration methods. AA7075 surface composites fabricated with different volume fractions of fly ash and emery particles is said to enhance the aforementioned properties. The composites are processed through friction stir process (rotational speed −1200 rpm, transverse speed – 56 mm/min, tool tilt angle – 2 °). During characterization, the Microstructural examination of surface composites depicts fine and homogenous distribution of reinforcements in the friction stir process region owing to severe plastic deformation and dynamic recrystallization process. Substantially, good interface is formed between the reinforcement particulates and base substrate. Inclusion of Fe3O4, Al2O3 and SiO2 constituents through fly ash and emery reinforcements associated with the homogenous dispersion strengthening mechanism favours for the superior hardness of surface hybrid composite specimen 50E50FA. Decremented grain size and load bearing capacity of the reinforcements is beneficial for the crack propagation resistance that enhances the impact toughness behaviour (17.4 J/cm2) of the same specimen. Wear rate of the specimens are evaluated through pin on disc tribometer. The decrease in the wear rate of hard specimen 50E50FA is observed due to the reduced contact area between its surface and counter disc. The morphology of worn specimens using SEM analysis shows the combined abrasive and adhesive wear as the worn mechanism.

K. Suganeswaran

Papers

Influence of secondary phase particles Al2O3/SiC on the microstructure and tribological characteristics of AA7075-based surface hybrid composites tailored using friction stir processing:

Investigations on micro hardness, electrical and thermal conductivity of AA7075 surface hybrid composites produced through friction stir processing

Process parameter optimization for the magnetic abrasive finishing of SS310s steel

Investigations on microstructure, thermo-mechanical and tribological behavior of graphene oxide reinforced AA7075 surface composites developed via friction stir processing

Influence of Fly Ash and Emery based particulate reinforced AA7075 surface composite processed through friction stir processing