Fused deposition modelling (FDM) is the most economical additive manufacturing technique. The purpose of this paper is to describe a detailed review of this technique. Total 211 research papers published during the past 26 years, that is, from the year 1994 to 2019 are critically reviewed. Based on the literature review, research gaps are identified and the scope for future work is discussed.,Literature review in the domain of FDM is categorized into five sections – (i) process parameter optimization, (ii) environmental factors affecting the quality of printed parts, (iii) post-production finishing techniques to improve quality of parts, (iv) numerical simulation of process and (iv) recent advances in FDM. Summary of major research work in FDM is presented in tabular form.,Based on literature review, research gaps are identified and scope of future work in FDM along with roadmap is discussed.,In the present paper, literature related to chemical, electric and magnetic properties of FDM parts made up of various filament feedstock materials is not reviewed.,This is a comprehensive literature review in the domain of FDM focused on identifying the direction for future work to enhance the acceptability of FDM printed parts in industries.

Fused deposition modelling: a review

Additive Manufacturing is currently growing fast, especially fused deposition modeling (FDM), also known as fused filament fabrication (FFF). When manufacturing parts use FDM, there are two key parameters—strength of the part and dimensional accuracy—that need to be considered. Although FDM is a popular technology for fabricating prototypes with complex geometry and other part product with reduced cycle time, it is also limited by several drawbacks including inadequate mechanical properties and reduced dimensional accuracy. It is evident that part qualities are greatly influenced by the various process parameters, therefore an extensive review of the effects of the following process parameters was carried out: infill density, infill patterns, extrusion temperature, layer thickness, nozzle diameter, raster angle and build orientation on the mechanical properties. It was found from the literature that layer thickness is the most important factor among the studied ones. Although manipulation of process parameters makes significant differences in the quality and mechanical properties of the printed part, the ideal combination of parameters is challenging to achieve. Hence, this study also includes the influence of pre-processing of the printed part to improve the part strength and new research trends such as, vacuum-assisted FDM that has shown to improve the quality of the printing due to improved bonding between the layers. Advances in materials and technologies that are currently under development are presented. For example, the pre-deposition heating method, using an IR lamp of other technologies, shows a positive impact on the mechanical properties of the printed parts.

Optimisation of Strength Properties of FDM Printed Parts-A Critical Review.

Biomaterials have emerged as a very important material class for wide application in medicine. Intensive research during the last decade strongly indicates that many health-related problems can be efficiently overcome with these new materials. Quality of life has been significantly increased for patients who need reconstructive surgeries, especially in comparison with old solutions. This paper reviews biomaterials in orthopedics that are used either as a support or substitute for bone tissues, from the aspect of their properties and state-of-the-art results in real clinical cases. Limitations and further directions of research are presented. Metal, ceramic and polymer materials, as well as new composites and new material structures, are reviewed, such as biodegradable porous materials and scaffolds. Nowadays, optimal selection of materials is one of the challenges imposed by the presence of many novel materials that can be used in specific applications. A general method of material selection is presented related to the hip stem and permanent metal biomaterials.

Review of Existing Biomaterials—Method of Material Selection for Specific Applications in Orthopedics

Ablation is a minimally invasive procedure used in the treatment of small tumours. Tumour sizes of about 3 cm are now been effectively treated with thermal ablation therapy using either microwave ablation or radiofrequency ablation. The impact of the slot position on a coaxial antenna on the extent of thermal lesion at the tumour site was investigated numerically in this study by varying the slot distance from the antenna tip using COMSOL Multiphysics as the modelling tool. The coaxial antenna size investigated has a diameter of 1.79 mm, with a central conductor diameter of 0.29 mm and Tefzel ETFE as the catheter material. The coaxial antenna performance was optimized at a slot distance of 6 mm from the antenna tip. The total power dissipation density and hence, the degree of thermal lesion created during the procedure is dependent on slot position of the coaxial antenna.

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Coaxial Antenna Slot Impact On Thermal Effectiveness In Microwave Ablation Therapy

Deformations in the vicinity of dental implants are affected by their design and if threshold level of 0.3 % is surpassed, bone resorption could occur. The goal of this study is to present a novel experimental approch for the analysis of effect od dental implant geometry on the surrounding structure strain values. A bone block model, with dimensions of 68x25x9 mm, was made from polymethyl-methacrylate. 3D printed block mold also provided a fixture for vertically placed Strauman ø4.0x12 mm. The sample was loaded in a three-point bending setup. The axial force of 600 N was applied on the dental implant. The Digital Image Correlation method was used for strain and displacement measurement.The highest von Mises strain of 0.7 % is located in the area of implant neck. The maximum displacement value in loading direction was 0.466 mm. Surface strain and displacement are correlated with implant geometry. This experimental methodology can be utilized to estimate dental implant load transfer characteristics.

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Experimental methodology for analysis of influence of dental implant design on load transfer

This paper investigates the opportunity of implementing FE simulations and rapid prototyping tecniques on titanium implant in maxillofacial surgery case based on osteotomy. Maxilla region was recorded by Cone Beam CT with high resolution and optimal radiation. Then, it followed the medical image reconstruction into 3D voxelized model. This model was converted both, to stl surface model for rapid prototyping, CAD modeling and FE mesh for simulation purposes with keeping good volume and dimensional consistency. Stl meshed surface was imported into CAD software, as initial 3d structure, which is used for parametric and customized design of implant. Since, the osteotomy is final application, it wassimulated the cutting and shifting of maxilla for proper correction by digital prototyping. Then, the fixation points for shifted maxilla were determined by surgeon to provide steady and tight joints between implanting screws and maxilla. Applied implant was given in initial standard flat configuration. Flat implant configuration was adapted by complex 3D bending in CAD software to be customized towards surface conformity of maxillofacial anatomy. By FE simulation in MSC Patran/Nastran, it was performed the stress analysis of implant with different thickness configurations and 3D bending, which provides the optimized implant model with best fit dimensions. Optimized implant model and corresponding body model were converted into physical models. RP model of maxilla was post-processed by cutting and boring to provide an adequate implant positioning according to digital prototypes. This approach facilitated the preparation of complex shaped implants in swept and lofted form, what had to be in high degree of conformity to anatomy surface. To approve a good practical opportunity, it was applied and tested in concrete surgery case of maxillofacial osteotomy.

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D. Djurdjevic

Papers

Implementation of FEM and rapid prototyping in maxillofacial surgery