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Large Scale Additive Manufacturing (LSAM) defines a system that can be used for printing components on the order of several meters at high extrusion rates (up to 50 kg/hr). The feed stock material is in the form of thermoplastic or fiber reinforced thermoplastic pellets which are almost 20 times cheaper than the filament based feedstock. The system has the potential to significantly affect automobile, aerospace and energy industries. However, the design constraints of small-scale 3D printing may not be applied to the large-scale printing due to the nature of the process. New design rules and limitations should be taken into consideration. In this study, the maximum bridging distance in large scale direct extrusion 3D printing system is investigated experimentally. A specially designed V-shaped model is used for testing. The experiments were carried out for 2 mm, 4 mm and 6 mm nozzle diameters under free- and forced-air cooling conditions. The failure of bead is determined in terms of break off and sags down. The maximum bridge distance is dependent on the printer settings (nozzle diameter, extrusion rate, travel speed, etc.), material, surface area-to-volume ratio of the extruded bead and cooling rate (thermal effects).

International Congress on 3D Printing (Additive Manufacturing) Technologies and Digital Industry
3D-PTC2019

Ömer Eyercioğlu Mehmet Aladağ Adem Aksoy Kursad Gov

Shaped metal deposition (SMD) is a relatively new additive layered manufacturing method. It is a novel technique to build net-shaped or near-net-shaped metal components in a layer-by-layer manner via applying metal wire and selection of a heat source such as laser beam, electron beam, or electric arc. SMD process is preferable as an alternative to traditional manufacturing methods especially for complex featured and large scale solid parts manufacturing and it is particularly used for aerospace structural components, manufacturing and repairing of dies/molds. TIG welding-based SMD method is implemented by depositing continuous wire melted via heat. In this study, the overhang (self supporting) angle in TIG welding-based shape metal deposition process is investigated. The overhang angles are the angles at which a 3D printer can build tapered (overhang) surfaces without the need to supporting material below the printing layer. The material, bead height, TIG weld parameters and the environment temperature (cooling rate of printed layer) are the parameters which affect the overhang angle. The results show that the maximum overhang angle is also dependent on the temperature of the previous layer. For the selected set of process parameters, the maximum overhang angle is found as 28 , if o the temperature of the previous layer is cooled to 150 C before the subsequent layer is deposited.

International Congress on 3D Printing (Additive Manufacturing) Technologies and Digital Industry
3D-PTC2019

Ömer Eyercioğlu Yusuf Atalay Mehmet Aladağ Oğuzhan Yılmaz