Among the several techniques for additive manufacturing (AM), fused deposition modelling (FDM) is widely used. Fused deposition modelling process uses a thermoplastic material, which is melted and then extruded layer by layer through a nozzle, in order to create a three‐dimensional object. As a result of the default setting of process parameters provided by the manufacturers, produced parts normally have a poor surface finish, low mechanical properties, low dimensional accuracy, and increased residual stresses compared to the parts produced using conventional manufacturing processes like molding (casting). Qualities of fused deposition modelled (FDMed) parts are generally affected by process parameters including the layer thickness, extrusion temperature, build orientation, printing speed, raster angle, infill density, raster width, nozzle diameter, and air gap. Increasing infill density, printing temperature, and decreasing print speed and layer thickness lead to increase mechanical strength and improve the surface finish of the printed parts. The optimal process parameters are preferred to achieve superior properties of the parts. This paper reviews the optimal fused deposition modelling process parameters on part qualities for making the stability of used deposition modelled parts for use. Various process parameters are identified in order to obtain desirable qualities in the manufactured parts. Areas for future research are proposed.

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Residual stresses induced during the layer-by-layer fabrication process affect mechanical properties and dimensional accuracy of additively manufactured components. Some of these effects cannot be corrected by post processing like heat treatment. This work aims at optimizing fused deposition modelling process parameters for the least residual stresses during 3D printing of carbon fiber reinforced nylon 12 hip implant. Taguchi design of experiment was used to study the effect of printing temperature, layer thickness and print speed on the residual stresses using the Digimat-additive manufacturing software. The results show that the optimal factor setting levels for minimizing part residual stresses were printing temperature of 255 °C, layer thickness of 0.3 mm, and a print speed of 50 mm/s. Printing temperature has the most significant influence on the residual stresses. The combination of the optimum parameter levels yielded the least simulation residual stresses of (41.75�6.53) MPa while the experimental residual stress results were (40.7�7.7) MPa. The simulated and experimental results agreed with minimal percentage difference of (2.51�0.04) %. Tensile and compressive properties of 3D printed carbon fiber nylon 12 composite hip implant matched those of cortical bone. The fracture surface of failed tensile specimens revealed that failure occurred through fiber pull-out and matrix fracture Keywords: Carbon fiber nylon 12 composite / fused deposition modelling (FDM) / hip joint implant / mechanical properties / residual stresses Schlüsselwörter: Kohlefaser-Nylon 12-Verbundwerkstoff / Schmelzschichtung (FDM) / Hüftimplantat / mechanische Eigenschaften / Eigenspannungen

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