Influence of Raster Pattern on Residual Stress and Part Distortion in FDM of Semi-Crystalline Polymers: A Simulation Study

Abstract

In fused deposition modelling (FDM) based on the selected raster pattern, the developed internal thermal residual stresses can vary considerably affecting the mechanical properties and leading to distinct part distortions. This phenomenon is more pronounced in semi-crystalline than amorphous polymers due to crystallisation. Hence, this study focuses on the simulation of the FDM process of a semi-crystalline polymer (polypropylene) with raster patterns such as line (90°/90°), line (0°/90°), zigzag (45°/45°), zigzag (45°/−45°), and concentric from Cura (slicing software). The simulation provides visualisation and prediction of the internally developed thermal residual stresses and resulting warpage with printing time and temperature. The sample with a line (90°/90°) raster pattern is considered as the reference sample in order to compare the relative levels of residual stress and warpage in the other printed/simulated samples. Among the considered raster patterns, the concentric pattern displays the lowest amount of warpage (5.5% decrease) along with a significant drop in residual stress of 21%. While the sample with a zigzag (45°/−45°) pattern showed the highest increase of 37% in warpage along with a decrease of 9.8% in residual stresses. The sample with a zigzag (45°/45°) pattern, exhibited a considerable increase of 16.2% in warpage with a significant increase of 31% in residual stresses. Finally, the sample with a line (0°/90°) raster pattern displayed an increase of 24% increase in warpage with an increase of 6.6% in residual stresses.

Effects of anisotropy and infill pattern on compression properties of 3D printed CFRP: mechanical analysis and elasto-plastic finite element modelling

“…Specimens were characterized by a slight curvature of the face in contact with the build plate, showing the effects of shrinkage and warping as observed in past works (Tekinalp et al. , 2014; Samy et al. , 2022; Wang et al.…”

“…The lateral interface between rasters is also a critical aspect of the material’s integrity; in fact, the newly fused material is deposited in a later stage with respect to the previously deposited one, with a time delay that depends on the printing speed and strategy (Sun, 2008; Sood et al. , 2012; Samy et al. , 2022).…”

Defects and residual stresses Finite Element prediction of FDM 3D printed Wood/PLA biocomposite

“…Cooling rates in the edge regions are significantly faster than in the central areas, owing to the better exposure of the former to the colder outer environment. This temperature profile could have implications for the mechanical properties and dimensional accuracy of FDM fabricated parts [31]. The temperature data presented in Figure 18 demonstrates the comparison of the temperature history curves, taken in pre-defined measuring point in the first deposited layer in specimens manufactured with same layer thickness of 0.15 millimetres, but varying nozzle temperature (220, 210 and 200 °C).…”

Reducing the Distortion in Particle Filled Material Extrusion (MEX)-Based Additive Manufacturing (AM) by Means of Modifying the Printing Strategy

“…Samy et al [14] investigated the influence of raster patterns on residual stress and distortion using semi crystalline polymers such as polypropylene (PP). They found that the kind of raster pattern and its deposition direction influence the distortion, as thermal effects such as phase transition (amorphous to crystalline) result in density gradients, leading to stresses in multilayers.…”