Estudio de la influencia del proceso de fabricación en las propiedades mecánicas de especímenes modelados por deposición fundida

El presente proyecto ha tenido como objetivo analizar la respuesta de las propiedades mecánicas de especímenes de ácido poliláctico (PLA) fabricados por modelado por deposición fundida. Se ha estudiado la influencia de seis parámetros de impresión en la resistencia a flexión mediante un diseño de experimentos L27 según los arreglos de Taguchi. Los parámetros que se han tenido en cuenta han sido: anchura de hilo, altura de capa, densidad de relleno, orientación de capa, velocidad y patrón de relleno. Los especímenes han sido testeados mediante ensayos a flexión en cuatro puntos y ensayos de fatiga. La combinación de parámetros óptimos obtenida será la que maximice la rigidez y resistencia a flexión. Los resultados han sido respaldados y avalados con fotografías microscópicas de las secciones de rotura y posteriormente se han validado comparándolos con otros resultados de un estudio anterior. Se ha determinado la mejor combinación de parámetros. La orientación es el parámetro más influyente, seguido de la altura de capa, la anchura de hilo y en menor medida la velocidad. La densidad y patrón de relleno no muestran influencia significativa. Las orientaciones de capa paralelas a las tensiones resultan las más resistentes y las propiedades mecánicas mejoran con alturas de capa pequeñas y anchuras de hilo grande

Comparison of thermal performance of 3D printer liquefiers through finite element models

Open source 3D printers have experienced an intense expansion during the last years, mainly because of their accessibility and the vast availability of information thanks to user communities. This fact presents researchers with a perfect context for hardware innovation, by improving the overall printing process, also in terms of durability of the printing machine. A 3D printer liquefier must transmit heat to the thermoplastic material in order to extrude it, reaching temperatures above 200 degrees for some materials like ABS on the tip of the nozzle. The design of the heating process must comply with keeping the balance between proper heating of the material and controlling the temperature along the extruding body, so that the printer itself is not harmed for overtemperature. On the other hand, the design must guarantee that the melting front is located in an intermediate point between the nozzle tip and the entrance of the raw material, to minimize pressure drops in the system, and so decreasing the demanding energy to the feeding motors. An alternative design of the heating system, Twist3D, is proposed in this paper.Peer ReviewedPostprint (published version

Mechanical properties of 3D-printing polylactic acid parts subjected to bending stress and fatigue testing

This paper aims to analyse the mechanical properties response of polylactic acid (PLA) parts manufactured through fused filament fabrication. The influence of six manufacturing factors (layer height, filament width, fill density, layer orientation, printing velocity, and infill pattern) on the flexural resistance of PLA specimens is studied through an L27 Taguchi experimental array. Different geometries were tested on a four-point bending machine and on a rotating bending machine. From the first experimental phase, an optimal set of parameters deriving in the highest flexural resistance was determined. The results show that layer orientation is the most influential parameter, followed by layer height, filament width, and printing velocity, whereas the fill density and infill pattern show no significant influence. Finally, the fatigue fracture behaviour is evaluated and compared with that of previous studies’ results, in order to present a comprehensive study of the mechanical properties of the material under different kind of solicitations.Peer ReviewedPostprint (published version

Estudio de la influencia del proceso de fabricación en las propiedades mecánicas de especímenes modelados por deposición fundida

El presente proyecto ha tenido como objetivo analizar la respuesta de las propiedades mecánicas de especímenes de ácido poliláctico (PLA) fabricados por modelado por deposición fundida. Se ha estudiado la influencia de seis parámetros de impresión en la resistencia a flexión mediante un diseño de experimentos L27 según los arreglos de Taguchi. Los parámetros que se han tenido en cuenta han sido: anchura de hilo, altura de capa, densidad de relleno, orientación de capa, velocidad y patrón de relleno. Los especímenes han sido testeados mediante ensayos a flexión en cuatro puntos y ensayos de fatiga. La combinación de parámetros óptimos obtenida será la que maximice la rigidez y resistencia a flexión. Los resultados han sido respaldados y avalados con fotografías microscópicas de las secciones de rotura y posteriormente se han validado comparándolos con otros resultados de un estudio anterior. Se ha determinado la mejor combinación de parámetros. La orientación es el parámetro más influyente, seguido de la altura de capa, la anchura de hilo y en menor medida la velocidad. La densidad y patrón de relleno no muestran influencia significativa. Las orientaciones de capa paralelas a las tensiones resultan las más resistentes y las propiedades mecánicas mejoran con alturas de capa pequeñas y anchuras de hilo grande

Comparison of thermal performance of 3D printer liquefiers through finite element models

Open source 3D printers have experienced an intense expansion during the last years, mainly because of their accessibility and the vast availability of information thanks to user communities. This fact presents researchers with a perfect context for hardware innovation, by improving the overall printing process, also in terms of durability of the printing machine. A 3D printer liquefier must transmit heat to the thermoplastic material in order to extrude it, reaching temperatures above 200 degrees for some materials like ABS on the tip of the nozzle. The design of the heating process must comply with keeping the balance between proper heating of the material and controlling the temperature along the extruding body, so that the printer itself is not harmed for overtemperature. On the other hand, the design must guarantee that the melting front is located in an intermediate point between the nozzle tip and the entrance of the raw material, to minimize pressure drops in the system, and so decreasing the demanding energy to the feeding motors. An alternative design of the heating system, Twist3D, is proposed in this paper.Peer Reviewe

Comparison of thermal performance of 3D printer liquefiers through finite element models

Open source 3D printers have experienced an intense expansion during the last years, mainly because of their accessibility and the vast availability of information thanks to user communities. This fact presents researchers with a perfect context for hardware innovation, by improving the overall printing process, also in terms of durability of the printing machine. A 3D printer liquefier must transmit heat to the thermoplastic material in order to extrude it, reaching temperatures above 200 degrees for some materials like ABS on the tip of the nozzle. The design of the heating process must comply with keeping the balance between proper heating of the material and controlling the temperature along the extruding body, so that the printer itself is not harmed for overtemperature. On the other hand, the design must guarantee that the melting front is located in an intermediate point between the nozzle tip and the entrance of the raw material, to minimize pressure drops in the system, and so decreasing the demanding energy to the feeding motors. An alternative design of the heating system, Twist3D, is proposed in this paper.Peer Reviewe

Mechanical properties of 3D-printing polylactic acid parts subjected to bending stress and fatigue testing

This paper aims to analyse the mechanical properties response of polylactic acid (PLA) parts manufactured through fused filament fabrication. The influence of six manufacturing factors (layer height, filament width, fill density, layer orientation, printing velocity, and infill pattern) on the flexural resistance of PLA specimens is studied through an L27 Taguchi experimental array. Different geometries were tested on a four-point bending machine and on a rotating bending machine. From the first experimental phase, an optimal set of parameters deriving in the highest flexural resistance was determined. The results show that layer orientation is the most influential parameter, followed by layer height, filament width, and printing velocity, whereas the fill density and infill pattern show no significant influence. Finally, the fatigue fracture behaviour is evaluated and compared with that of previous studies’ results, in order to present a comprehensive study of the mechanical properties of the material under different kind of solicitations.Peer Reviewe