Mechanical and dimensional assessment of threaded fasteners manufactured using 3D printing

The fused filament fabrication (FFF) has several applications for engineering; however, a possible limitation is the few studies on thread fillets. Therefore, this work aimed to evaluate thread fillets, taking into account both mechanical capacity and geometric quality. With this aim, specimens were developed for tensile tests with variations in filling percentage (15% and 55%), number of filaments in the wall (2 and 6), material (ABS and PLA), and filament height (10 mm and 20 mm). In addition to the tests, extra test specimens were developed to observe microscopically the values of the angles reached by the printed fillets. The results demonstrated that all the parameters studied were relevant to the maximum force, especially the filling percentage. In addition, there was a high interaction between parameters, which may indicate a geometric readjustment due to these interactions. Finally, related to the thread angles, the limitation of 3D printing by FFF seems to limit the printing of sharp angles.