The mechanical behaviour of specimens fabricated using FDM machine has been thoroughly studied and several works have been presented. However, they are focused on few materials, in particular ABS, while very few papers analysed the mechanical properties of FDM samples made by PLA filament. Even though ABS is well known for its superior mechanical properties, some applications might require materials with other properties, such as PLA. Therefore, a deeper investigation of the effect of the process on its properties is needed. In this study, at first, the influence of the main FDM process parameters, such as raster angle, extrusion width, air gap and extrusion temperature, on mechanical performance of PLA samples has been evaluated. The mechanical tests have been carried out on miniaturized tensile specimens focusing on the tensile test main properties: Ultimate tensile stress, Young modulus and elongation at break. Moreover, an experimental campaign has been carried out on the effect of a thermal postprocessing, in order to evaluate the effects of the treatment and its relation with the process parameters on the mechanical properties of the specimens.

Bioepoxy based monomers were formulated with a cure inhibitor and a cleavable amine to obtain a recyclable epoxy system suitable for resin infusion at room temperature. Hybrid flax/carbon fiber layup were used. Tensile, flexural and dynamo-mechanical properties for the composites were studied. The cured laminates were chemically recycled obtaining from the epoxy matrix a thermoplastic. The recycled was processed by fused deposition modelling (FDM) and injection molding after mixing with short kenaf fibers. (C) 2017 Elsevier Ltd. All rights reserved.

The mechanical behaviour of specimens fabricated using FDM machine has been thoroughly studied and several works have been presented. However, they are focused on few materials, in particular ABS, while very few papers analysed the mechanical properties of FDM samples made by PLA filament. Even though ABS is well known for its superior mechanical properties, some applications might require materials with other properties, such as PLA. Therefore, a deeper investigation of the effect of the process on its properties is needed. In this study, at first, the influence of the main FDM process parameters, such as raster angle, extrusion width, air gap and extrusion temperature, on mechanical performance of PLA samples has been evaluated. The mechanical tests have been carried out on miniaturized tensile specimens focusing on the tensile test main properties: ultimate tensile stress, Young modulus and elongation at break. Moreover, an experimental campaign has been carried out on the effect of a thermal post-processing, in order to evaluate the effects of the treatment and its relation with the process parameters on the mechanical properties of the specimens.

In recent years, fused deposition modelling technology (FDM) has become one of the most important additive manufacturing technology due to its capability to produce functional prototypes with complex shape in a cost effective way. Recently, the trend towards miniaturization invested also this technology, since the request of micro-component is rapidly growing due to the increasing number industrial sectors involved. Mechanical properties are fundamental in some sectors of high-quality micro-parts, so the knowledge of the influence of FDM process parameters on mechanical properties can be useful to extend its application and help the optimization of the parameter selection. In this context, the aim of this study is the analysis of the FDM capability and the room for improvement, through a comparison with a wellconsolidated industrial process, such as the micro-injection moulding. Although FDM quality cannot compete with the technologies industrially used for final products, its low cost and short time are very attractive for some applications. Moreover, the comparison can be interesting since FDM is often used to manufacture prototypes eventually made with more performing industrial technologies, so that a measure of the quality and functionality of these prototypes can be extremely useful for product developers.

3D printers based on the additive manufacturing technology create objects layer-by-layer dropping fused material. As a consequence, strong overhangs cannot be printed because the new-come material does not find a suitable support over the last deposed layer. In these cases, one can add support structures (scaffolds) which make the object printable, to be removed at the end. In this paper, we propose a level set based method to create object-dependent support structures, specifically conceived to reduce both the amount of additional material and the printing time. We also review some open problems about 3D printing which can be of interests for the mathematical community.

Purpose: The main purpose of this research work is to study the effect of poly lactic acid (PLA) addition into poly (e-caprolactone) (PCL) matrices, as well the influence of the mixing process on the morphological, thermal, chemical, mechanical and biological performance of the 3D constructs produced with a novel biomanufacturing device (BioCell Printing). Design/methodology/ approach: Two mixing processes are used to prepare PCL/PLA blends, namely melt blending and solvent casting. PCL and PCL/PLA scaffolds are produced via BioCell Printing using a 300-mm nozzle, 0/908 lay down pattern and 350-?m pore size. Several techniques such as scanning electron microscopy (SEM), simultaneous thermal analyzer (STA), nuclear magnetic resonance (NMR), static compression analysis and Alamar BlueTM are used to evaluate scaffold's morphological, thermal, chemical, mechanical and biological properties. Findings: Results show that the addition of PLA to PCL scaffolds strongly improves the biomechanical performance of the constructs. Additionally, polymer blends obtained by solvent casting present better mechanical and biological properties, compared to blends prepared by melt blending. Originality/value: This paper undertakes a detailed study on the effect of the mixing process on the biomechanical properties of PCL/PLA scaffolds. Results will enable to prepare customized PCL/PLA scaffolds for tissue engineering applications with improved biological and mechanical properties, compared to PCL scaffolds alone. Additionally, the accuracy and reproducibility of by the BioCell Printing enables to modulate the micro/macro architecture of the scaffolds enhancing tissue regeneration. © Emerald Group Publishing Limited.