Investigating the factors affecting the strength of parts produced by FFF 3D printers

Nowadays, extrusion-based additive manufacturing is an emerging manufacturing method that is receiving much attention and is the basis of FFF 3D printers. In this method, molten polymer is deposited layer by layer through a nozzle to create a three-dimensional object. Due to the rapid freezing of the layers, small gap and cavities may be created between the layers and lead to a decrease in the mechanical properties, including the strength of the parts. Since predicting and improving the mechanical properties is one of the challenges of this production method, the purpose of this study is to investigate the factors affecting the strength of parts produced by FFF. Investigation of the previous studies shows that the influencing factors are the nozzle temperature, filling percentage, sample alignment, filament deposition angle, layer thickness and nozzle diameter. Furthermore, it is concluded that increasing the nozzle temperature, filling percentage, and nozzle diameter and decreasing the layer thickness improve the strength of the produced parts. This is due to an increase in the contact surface of the deposited filaments as well as a decrease in the empty gaps between them. Also, considering the deposition angle in the tension axis of the part can greatly increase its strength.