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Optimizing Fused Deposition Modelling Process Parameters for Medical Grade Polymethylmethacrylate Flexural Strength

Obaeed Nareen Hafidh, Hamdan Wisam K.

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

349--359

EN

The production of functional parts, including those employed by the biomedical industry has been achieved a promising candidate in Fused Deposition Modelling (FDM). The essential properties of these biomedical parts which manufactured by additive manufacturing as compared to some other conventional manufacturing processes depend on structural and process parameters rather than material properties alone. Regarding to the evaluation the flexural strength of medical-grade, Polymethylmethacrylate PMMA has been received relatively very little investigation to date. PMMA is a biocompatible filament that be used in manufacturing of patient-specific implants such as dental prosthesis and orthopaedic implants. The proposed work explores the effect of three process parameters that vary with respect of three levels on the flexural strength. These levels can be specified by layer height (120, 200, 280 µm), infill density (40, 65, 90 %) and skewing angle (0º, 45º, 90º) on the flexural strength of medical-grade PMMA. Maximum and minimum flexural strength that be obtained in this work about (93 and 57 MPa) respectively. The analysis of variance (ANOVA) results shows that the most effective factor is the layer height followed by infill density. The flexural strength rises significantly with decreases layer height and the skewing angle is in zero direction. The process parameters have been optimized through utilizing of genetic algorithms. The optimal results that emerged based on genetic algorithm technique are approximately (276 μm) as layer height, (46 %) infill density and skewing angle (89 º) which maximize the flexural strength to (97 MPa) at crossover for ten generation.

2

Viscoelastic characterization of additively manufactured acrylonitrile butadiene styrene

Witek Szczepan

Computer Methods in Materials Science

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2023

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Vol. 23, No. 2

39--44

EN

The main objective of this work was to characterize the viscoelastic properties of additively manufactured Acrylonitrile Butadiene Styrene based on tensile stress relaxation tests. The stress relaxation measurements were conducted with a temperature range of 25–100°C. The two-layer viscoplastic constitutive model was adopted to describe the elastic and viscous behavior of the investigated material. The model parameters were calibrated using an inverse analysis and stress relaxation data. The model’s predictive capabilities were assessed by comparing the model predictions with experimental data not included in the calibration process.

3

The influence of Material Extrusion process parameters on the porosity and mechanical properties of PLA products for medical applications

Rusińska Małgorzata, Gruber Piotr, Ziółkowski Grzegorz, Łabowska Magdalena, Wilińska Karolina, Szymczyk-Ziółkowska Patrycja

Acta of Bioengineering and Biomechanics

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2023

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Vol. 25, no. 3

EN

The study addresses the growing need for personalized medicine and cost-effective manufacturing by investigating additive manufacturing (AM). It employs the Design of Experiments (DOE) to explore how fused filament fabrication (FFF) parameters affect porosity and mechanical properties of medical-grade polylactide (PLA) samples.

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Surface Roughness Reduction in A Fused Filament Fabrication (FFF) Process using Central Composite Design Method

Kandananond Karin

Production Engineering Archives

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2022

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Vol. 28, Iss. 2

157--163

EN

The objective of this study is to optimize the fabrication factors of a consumer-grade fused filament fabrication (FFF) system. The input factors were nozzle temperature, bed temperature, printing speed, and layer thickness. The optimization aims to minimize average surface roughness (Ra) indicating the surface quality of benchmarks. In this study, Ra was measured at two positions, the bottom and top surface of benchmarks. For the fabrication, the material used was the Polylactic acid (PLA) filament. A response surface method (RSM), central composite design (CCD), was utilized to carry out the optimization. The analysis of variance (ANOVA) was calculated to explore the significant factors, interactions, quadratic effect, and lack of fit, while the regression analysis was performed to determine the prediction equation of Ra. The model adequacy checking was conducted to check whether the residual assumption still held. The total number of thirty benchmarks was fabricated and measured using a surface roughness tester. For the bottom surface, the analysis results indicated that there was the main effect from only one factor, printing speed. However, for the top surface, the ANOVA signified an interaction between the printing speed and layer thickness. The optimal setting of these factors was also recommended, while the empirical models of Ra at both surface positions were also presented. Finally, an extra benchmark was fabricated to validate the empirical model.

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A generic method to realize long fibers filled and large polymer parts in additive manufacturing

Hascoët Jean-Yves, Authelin Olivier, Rauch Matthieu

Journal of Machine Engineering

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2020

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Vol. 20, No. 1

107--116

EN

A general manufacturing methodology for long fibers filled and large polymer (LFFLP) parts will be proposed, which constitutes the major scientific contribution of the document. The input, output, control and analysis data at each step of the methodology will be specified. Experiments realized in the laboratory of Ecole Centrale de Nantes will demonstrate the relevance and effectiveness of this method applied to a 6-axis robot and the FFF process by showcasing two light and resistant lattice structures. The latter also highlight the capacity of 6-axis robots for orienting the deposition head in order to generate complex trajectories. Finally, perspectives and future research about this subject will be discussed such as the need to develop in-depth analyses of the manufacturing methodology. The possibility of using continuous fibres composites as material feedstock for robotized large dimensions FFF will also be covered.