José Porras

Purpose: The purpose of this paper is to analyze the aerodynamic improvements obtained in a wing section with a NACA 0018 airfoil manufactured using the fused deposition modeling (FDM) technique with regard to a smooth surface made by milling. The creation of micro-riblets on the surface of the airfoil, due to the deposition of the material layer by layer, improves the general aerodynamic performance of the parts, provided that the riblets are parallel to the flow line. The incidence of the thickness of the thread deposited in each layer – to be the variable on which the geometry of the riblets is based – was studied. Design/methodology/approach: The wing section was designed using 3D software. Three different models were designed by rapid prototyping, using additive and subtractive manufacturing. Two of the profiles were manufactured using FDM varying the thickness of the layer to be able to compare the aerodynamic improvements. The third model was manufactured using a subtractive rapid prototyping machine generating a smooth surface profile. These three models were tested inside the wind tunnel to be able to quantify the aerodynamic efficiency according to the geometry and the riblets size. Findings: The manufacture of an aerodynamic profile using FDM provides, in addition to the lightness and the ability to design parts with complex geometries, an improvement in the aerodynamic efficiency of 10 per cent compared with profiles with a smooth surface. Practical implications: With the aerodynamic advantage gained through the use of FDM positions, the additive manufacturing serves as an excellent alternative for the manufacture of lightweight aerodynamic parts, with low structural loading and with low Reynolds number (∼5·105). This technological advantage would be applied to the UAV (unmanned aerial vehicle) industry. Originality/value: The study carried out in this article demonstrates that the use of FDM as a manufacture process of end-used parts that are subject to movement generates an additional advantage that had not been considered. The additive manufacturing allows us to directly manufacture riblets by creating the necessary surface so as to reduce the aerodynamic drag.

Agustín de Betancourt and Molina was one of the most distinguished engineers of the eighteenth and nineteenth century with numerous contributions to various fields of engineering, including civil engineering. This research shows the process followed in the documentation of the cultural heritage of that canary engineer, especially in the geometric documentation of the wind machine to drain marshy grounds designed in 1789. The baseline information has been recovered from the Canary Orotava Foundation of History of Science who has spent years collecting information about the Project Betancourt, in particular, planimetric information as well as a small report on its operation and description of parts of machine. From this information, we have obtained its 3D reconstruction using CAD techniques with the cooperation of Solid Edge ST7 parametric software, which has enabled to obtain the 3D model as well as different detail plans and exploded views.

Agustín de Betancourt y Molina was one of the most distinguished engineers of the eighteenth and nineteenth centuries with numerous contributions to various fields of engineering, including civil engineering. This research shows the process followed in the documentation of the cultural heritage of that Canary engineer, especially in the geometric documentation of a machine for cutting grass in waterways presented in England in 1795 after three years researching on theory of machines. The baseline information has been recovered from the Canary Orotava Foundation of History of Science who has spent years collecting information about the Project Betancourt, in particular, planimetric information as well as a small report on its operation and description of parts of machine. From this information, we have constructed a three dimensional (3D) model using CAD techniques with the use of Solid Edge ST7 parametric software, which has enabled the team to create the 3D model as well as different detail plans and exploded views.

Would it be possible for an additively manufactured impeller of fused deposition modeling (FDM) technology to have a functional behavior and a similar performance to that of the original impeller of a close-coupled centrifugal pump? In this research paper, different tests are conducted to answer this question and to evaluate the manufacturing process of FDM functional parts. Three performance experiments with the same centrifugal pump, using an open test rig, are carried out and compared, first using the original impeller provided by the manufacturer of the pump, second using an FDM replication of the original one without post-treatment, and third using a chemically dimethyl ketone post-treated FDM replication. The results obtained in the tests demonstrate the functional behavior of both additive FDM impellers in comparison with the one fabricated by means of conventional technology (subtractive manufacturing). Additionally, analogous head-flow curves (and also with an improved performance to the one of the original impeller) are obtained. This research paper introduces significant information concerning a low-cost and low-time manufacturing process of additive functional parts. Moreover, new results are presented regarding the performance of chemically post-treated FDM parts working in functional applications. FDM impellers of high complexity and quality, which meet performance criteria, can be achieved.