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Compared to conventional manufacturing processes, fused deposition (FD)‐based layered manufacturing processes have dramatically reduced the part design and manufacturing time. However, it is necessary to further enhance their process productivity. To this end, improvement of FD process efficiency is studied in this paper. A build time analysis is conducted and the deposition parameters that can be used to speed up fabrication processes are identified. The tool path‐based deposition planning approach is extended for ensuring layer quality when the build process is expedited under adjusted deposition parameters. A test part was built to demonstrate the proposed approach.

This paper aims to develop an integrated and portable desktop 3D printer using direct extruding technology to expand applied material field. Different from conventional fused deposition modeling (FDM) which uses polymer filaments as feedstock, the developed system can fabricate products directly using polymer pellets. And its printing properties are also investigated.

A conical screw-based extrusion deposition (CSBED) system was developed with a large taper conical screw to plasticize and extrude fed materials. The 3D printer was developed with assistance of precision positioning and controlling system. Biocompatible thermoplastic polyurethane (TPU) pellets were selected as raw materials for experiments. The influences of four processing parameters: nozzle temperature, fill vector orientation, layer thickness and infill density on the product’s internal structure and tensile properties were investigated.

It is concluded that the customized system has a high manufacturing accuracy with a diminutive global size and is suitable for printing soft materials such as TPU. Theoretical calculation shows the developed conical screw is more effective in plasticizing and extruding compared with conventional screw. Printed samples can achieve applicable tensile properties under harmonious parameter cooperation. Deposited materials are found to have voids among adjacent roads under unbefitting parameters.

The developed system efficiently improves material limitations compared to commercial FDM systems and exhibits great potential in medical field because soft materials such as biocompatible TPU pellets can be directly used.

This study aims to characterize the suitability of a direct extrusion process in the fused layer manufacturing (FLM)-method under processing of granulated plastics.

In this paper, a granulate-based direct extrusion system in the FLM method is presented. This system is characterized with respect to the strand deposition mechanism and resulting component properties (geometrically and mechanically).

The extruder output could be identified as a linear relation between the applied extruder speed and the resulting mass flow. A developed model for the material and temperature-dependent strand deposition process was validated under experimental investigations. Further, it was possible to define process windows to realize desired strand widths and strand heights. In addition, analyses were conducted to determine the tensile strength transversely to the orientation of the layer plane.

The extrusion system was characterized under the processing of materials ABS Magnum 8434 and PLA Ingeo 4043D. Due to the restricted choice of materials, further investigations are planned under an extension of the test materials. Furthermore, the degree of the geometric complexity of the test components should be increased to finally characterize the process.

By means of the characterization of the direct extrusion system, it is possible for users to classify the process and to use the process in specific application areas. In comparison to filament-based extrusion systems, significant advantages can be achieved by means of direct extrusion. These include, for example, the use of less expensive work materials (by factor >10), the use of existing test certificates and the advantage of higher mechanical properties. This makes it possible to meet modern product requirements and to produce competitive components.

This paper aims to study strength properties and accuracy of a new type of composites, in which matrix is manufactured additively, whereas infill is a polyurethane resin. The process of manufacturing these composites is invented and patented by authors.

The authors developed a method of manufacturing composites, which was then used to build samples for tensile and bending tests (according to ISO 572 and ISO 178 standards), as well as measurements of accuracy.

It was found that the method of composite manufacturing designed by the authors allows obtaining both stronger and cheaper parts in comparison with the traditional acrylonitrile butadiene styrene FDM parts.

The research was limited to static tests only, and no dynamic tests were performed on the manufactured samples. The accuracy analysis is only a basic one.

Developed method allows to shorten the FDM process with simultaneous decrease of costs (in professional processes) and increase of strength of obtained products.

Application of composite materials presented in the paper will significantly expand possibilities of using FDM method to manufacture functional, strong parts able to carry higher loads. Application of different combinations of thermoplastic matrix materials with different resin infills will allow to control properties of obtained composites. The solution is currently subject of a patent.

Material extrusion additive manufacturing, also known as fused deposition modeling, is a manufacturing technique in which objects are built by depositing molten materials layer-by-layer through a nozzle. The use and application of this technique has risen dramatically over the past decade. This paper aims to first, report on the production and characterization of a shape memory polymer material filament that was manufactured to print shape memory polymer objects using material extrusion additive manufacturing. Additionally, it aims to investigate and outline the effects of major printing parameters, such as print orientation and infill percentage, on the elastic and mechanical properties of printed shape memory polymer samples.

Infill percentage was tested at three levels, 50, 75 and 100 per cent, while print orientation was tested at four different angles with respect to the longitudinal axis of the specimens at 0°, 30°, 60° and 90°. The properties examined were elastic modulus, ultimate tensile strength and maximum strain.

Results showed that print angle and infill percentage do have a significant impact on the manufactured test samples.

Findings can significantly influence the tailored design and manufacturing of smart structures using shape memory polymer and material extrusion additive manufacturing.

This paper aims to design and test a system capable of coaxial fused deposition modelling (FDM) and assess the coaxial fibres produced for their coaxial concentricity. The goal is to achieve concentricity values below the literature standard of 15 per cent.

This research discusses the design of the coaxial nozzle internal geometry and validates the modelling process by using computational fluid dynamics to assess its flow profile. Sequentially, this paper discusses the abilities of current additive manufacturing (AM) technology in the production of the coaxial nozzle.

The methodology followed has produced coaxial fibres with concentricity values as low as 2.89 per cent and also identifies a clear speed suitable for coaxial printing using polylactic acid (PLA) as the internal and external materials.

The concentricity of the printed fibres is heavily influenced by the feed rate for the thermoplastic feedstock. This in turn alters the viscosity of the material to be printed, implying that a relationship exists between feed rate and print temperature, which can be further optimised to potentially obtain higher concentricity values.

This paper adds reliability and repeatability to the production of coaxially printed structures, the likes of which has numerous potential applications for biological printing.

The outcomes of this study will provide an AM platform to alter the paradigm of biofabrication by introducing a new level of versatility to the construction of biofabricated structures.

Examines the process of selective laser sintering [SLS] for rapid prototyping. Begins with a brief history of [SLS] then describes the main components of the SLS system, the build materials which are used and the actually process operating cycle by which models are produced. Looks at the 3‐D CAD data preparation and factors affecting the quality of the models. Concludes that selective laser sintering is a continually developing process and in particular much effort is being spent on the development of new materials for the models.

The evaluation of novel materials such as the acrylonitrile styrene acrylate (ASA) for tribological and mechanical conditions can provide a structural protection against the environmental and wear effects that results in the long-term integrity of the 3 D printed parts. Results of the experimental stage are intended to identify the influence of the printing conditions on the functional characteristics of ASA parts that results in variations of the friction coefficient, wear rate and tensile response. In addition, this study aims to highlight the relevance of printing parameters to avoid the use of chemical post-processing stages, increasing the performance and sustainability of the process.

In this research, an evaluation of the influence of printing parameters of layer thickness and temperature on the mechanical and tribological response have been carried out for ASA specimens manufactured by fused filament fabrication technology. For this purpose, a range of three different values of thickness of fused layer and three different printing temperatures were combined in the manufacturing process of tests samples. Mechanical behavior of the printed parts was evaluated by standard tensile tests, and friction forces were measured by pin-on-disk tribological tests against steel spheres.

Higher layer thickness of the printed parts shows lower resistance to tribological wear effects; in terms of friction coefficient and wear rate, this type of parts also presents lower tensile strength. It has been detected that mechanical and tribological behavior is highly related to the micro-geometrical characteristics of the printed surfaces, which can be controlled by the manufacturing parameters. Under this consideration, a reduction in the coefficient of friction near to 65% in the average value was obtained through the variation of the layer thickness of printed surfaces.

This research aims to fill a gap in the scientific literature about the use of specific additive manufacturing materials under dynamic contact. This paper is mainly focused on the influence of the manufacturing parameters on the tribological and mechanical behavior of a weather resistant polymer (ASA).

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.

This paper aims to study the interfacial and interlayer bonding of Polylactic acid parts manufactured by fused deposition modelling. Different layer thicknesses are analysed in the manufacture of these pieces and the lack of material associated with this parameter is verified. The influence of the immersion of these parts in different solvents is also studied, as they are increasingly used in the improvement of the surface finish. Tomography results are also obtained in which the increase in density of the parts subjected to these treatments is demonstrated.

The material used in this study is a 1.75-mm diameter polylactic acid (PLA) filament from fused filament fusion world. Monolayer and multilayer samples have been manufactured. The manufactured parts were subjected to solvent immersion for a period of 60 s. The solvents used are chloroform (CHCl3), dichloromethane (CH2Cl2), tetrahydrofuran (C4H8O) and ethyl acetate (C4H8O2). The pieces were then dried for 48 h. The interior of the samples was evaluated by two techniques: microscopy and tomography.

With this study, it has been observed that the thickness of the layer affects the porosity interfacial to a greater extent than in the interlayer, causing the increase in porosity as this thickness is increased.The impact of different chemical treatments (immersions in different solvents) on the internal quality of the parts has been evaluated. All the solvents analysed soften the surface as they cause the softening of the material and its possible redistribution. In the interior, however, they affect in a lighter way. The retention of solvents in the porosity of the pieces is also checked, especially pronounced in the areas close to the surface. Finally, changes are observed in the density of the pieces, related to the partial crystallization of the samples.

All that has been studied shows that the application of chemical post-processes not only affects the surface texture of the parts, or the less studied mechanical properties, but also affects the interfacial union of the parts in a very different way. This is the first study carried out on this aspect with polylactic acid (PLA) and post-processing methods.