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Purpose Fused filament fabrication or fused deposition modeling (FFF/FDM) has as one of its main restrictions the surface quality intrinsic to the process, especially linked to the layer thickness used during manufacture. The purpose of this paper is to study the possibility of improving the surface quality of polylactic acid (PLA) parts manufactured by FFF using the shot blasting technique. Design/methodology/approach The influence of corundum blasting on 0.2 mm layer thickness FDM PLA parts treated with two sizes of abrasive, different exposure times and different incidence pressures. Findings As a result, improvements of almost 80% were obtained in the surface roughness of the pieces with high exposure times, and more than 50% in just 20 s. Originality/value This technique is cheap, versatile and adaptable to different part sizes and geometries. Furthermore, it is a fast and environmentally friendly technique compared to conventional machining or vapor smoothing. Despite this, no previous studies have been carried out to improve the quality of this technology.

We describe a methodology to obtain three-dimensional models of engineered surfaces using scanning electron microscopy and multi-view photogrammetry (3DSEM). For the reconstruction of the 3D models of the surfaces we used freeware available in the cloud. The method was applied to study the surface roughness of metallic samples patterned with parallel grooves by means of laser. The results are compared with measurements obtained using stylus profilometry (PR) and SEM stereo-photogrammetry (SP). The application of 3DSEM is more time demanding than PR or SP, but it provides a more accurate representation of the surfaces. The results obtained with the three techniques are compared by investigating the influence of sampling step on roughness parameters.

DMLS (Direct Metal Laser Sintering) Additive manufacturing allows building topological optimized geometries with good mechanical properties and low weight. These features are appropriated for the aeronautical industry because the reduction of weight involves saving costs per trip. However, the manufacturing cost using SLM (Selective Laser Melting) or DMLS, is also high since titanium alloys powder is expensive. Therefore, this work aims to explore the possibility of using 15-5PH stainless steel powder to balance the mechanical properties, weight and cost of the part.

Ti-5Al-5V-5Mo-3Cr (Ti5553) is a metastable β titanium alloy with a high potential use in the aeronautic industry due to its high strength, excellent hardenability, fracture toughness and high fatigue resistance. However, recent research shows this alloy has a limited weldability. Different welding technologies have been applied in the literature to weld this alloy, such as electron beam welding (EBW), gas tungsten arc welding (GTAW) or laser beam welding (LBW) under keyhole regime. Thus, in tensile tests, joints normally break at the weld zones, the strength of the welds being always lower than that of the base metal. In the present work, a novel approach, based on the application of LBW under conduction regime (with a High-Power Diode Laser, HPDL), has been employed for the first time to weld this alloy. Microstructure, microhardness and strength of obtained welds were analyzed and reported in this paper. LBW under conduction regime (LBW-CR) leads to welds with slightly higher values of Ultimate Tensile Strength (UTS) than those previously obtained with other joining processes, probably due to the higher hardness of the fusion zone and to lower porosity of the weld.

A novel and simple transcription strategy has been designed for the template-synthesis of CePO4 xH2O nanofibers having an improved nanofibrous morphology using a pH-sensitive nanofibrous hydrogel (glycine-alanine lipodipeptide) as structure-directing scaffold. The phosphorylated hydrogel was employed as a template to direct the mineralization of high aspect ratio nanofibrous cerium phosphate, which in-situ formed by diffusion of aqueous CeCl3 and subsequent drying (60 C) and annealing treatments (250, 600 and 900 C). Dried xerogels and annealed CePO4 powders were characterized by conventional thermal and thermogravimetric analysis (DTA/TG), and Wide-Angle X-ray powder diffraction (WAXD) and X-ray powder diffraction (XRD) techniques. A molecular packing model for the formation of the fibrous xerogel template was proposed, in accordance with results from Fourier-Transformed Infrarred (FTIR) and WAXD measurements. The morphology, crystalline structure and composition of CePO4 nanofibers were characterized by electron microscopy techniques (Field-Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy/High-Resolution Transmission Electron Microscopy (TEM/HRTEM), and Scanning Transmission Electron Microscopy working in High Angle Annular Dark-Field (STEM-HAADF)) with associated X-ray energy-dispersive detector (EDS) and Scanning Transmission Electron Microscopy-Electron Energy Loss (STEM-EELS) spectroscopies. Noteworthy, this templating approach successfully led to the formation of CePO4 H2O nanofibrous bundles of rather co-aligned and elongated nanofibers (10–20 nm thick and up to ca. 1 m long). The formed nanofibers consisted of hexagonal (P6222) CePO4 nanocrystals (at 60 and 250 C), with a better-grown and more homogeneous fibrous morphology with respect to a reference CePO4 prepared under similar (non-templated) conditions, and transformed into nanofibrous monoclinic monazite (P21/n) around 600 C. The nanofibrous morphology was highly preserved after annealing at 900 C under N2, although collapsed under air conditions. The nanofibrous CePO4 (as-prepared hexagonal and 900 C-annealed monoclinic) exhibited an enhanced UV photo-luminescent emission with respect to non-fibrous homologues.