Surface plastic flow of three-dimensional printed polylactic acid in the tribological study of surface patterned polymer

The potential of three-dimensional (3D) printing in polymer tribology is poorly explored. Material alignment and composition play vital roles in altering the friction and wear characteristics of 3D printed materials. In the current study, 3D patterns made by fused deposition modelling are used to print advanced tribo-composites. Two different surface patterns (line and circular) are provided through 3D printing using white and silver polylactic acid (PLA). The deformation and distribution of white and silver PLA over the samples surface are observed after a wear test. Results showed that the coefficient of friction is not influenced by changes in the surface pattern. However, the wear rate increased for samples with line patterns on the contact surface, since plastic flow was more significant in this case. Moreover, the filling factor exhibited an influence on increasing the plastic flow of the contact surface for samples with a line pattern

Simplified local infill size optimization for FDM printed PLA parts

The great advantage of additive manufacturing is the fact that hollowed parts with a given infill can be created. However, the standardized commercial slicer software offers a uniform infill pattern creation solution. In engineering practice, the manufactured parts are functional, therefore the appropriate load bearing capacity is mostly mandatory. In this paper a simplified local infill size optimization method has been presented. Based on a Finite Element Analysis the local density of the pattern can be adjusted, according to the emerged local stresses. The results show that independently of the pattern type, if the scaling was applied, the mechanical resistance was improved to the same extent. In case of the worst-performing uniform pattern, 84% improvement in mechanical resistance was achieved with the optimization. In addition, an FDM printing problem has been highlighted, which must be eliminated if the proposed method is used

Effect of infill pattern scaling on mechanical properties of FDM-printed PLA specimens

3D printing offers a significant advantage in the production of hollow parts through the use of infill patterns. However, these patterns are typically generated by slicer software with a primary focus on providing basic structural rigidity, while neglecting other important criteria. This paper presents a simplified infill scaling technique for fused deposition modeling (FDM) and evaluates its effectiveness through tensile tests. The research question addressed in this study is whether adjusting the size of the pattern can reduce print time while maintaining the same stiffness at a given infill ratio. The methodology involves analyzing the results obtained from the tensile tests. The findings reveal that the print time can be reduced to some extent by properly adjusting the size of the infill pattern. However, it is observed that the mechanical resistance is influenced by the layer formation process. In conclusion, this research contributes to understanding the relationship between infill scaling, print time reduction, and mechanical resistance in FDM 3D printing

Part orientation optimization for Wire and Arc Additive Manufacturing process for convex and non-convex shapes

Building orientation optimization for Additive Manufacturing (AM) process is a crucial step because it has a vital effect on the accuracy and performance of the created part. Wire and Arc Additive Manufacturing’s (WAAM) working space is less limited, and the production time is significantly shorter than the other metal 3D printers. However, one of the adverse effects of WAAM is the defect at the start and endpoints of the welding beads. In this paper, an algorithm has been invented to define the optimal printing position, reducing the number of these defects by rotating the 3D object in a loop around the X and Y axes by a small constant degree and then selecting the degree of rotation that has the fewest uninterrupted surfaces and the largest area of the first layer. The welding process will be interrupted as little as possible by the torch if there are the fewest possible uninterrupted surfaces. As a result, there will be fewer defects in the production and finishing of the welding beads. In order to have a sufficient connection surface with the build tray, which will aid in holding the workpiece in place, the largest first layer should also be sought. Therefore, it has been found that a properly defined orientation relative to the build tray can reduce the number of uninterrupted surfaces within the layers, which will improve the expected dimensional accuracy of the parts. The efficiency of the process is highly affected by the shape of the part, but in most cases, the print errors can be drastically minimized

Concurrent shape and build orientation optimization for FDM additive manufacturing using the principal stress lines (PSL)

Additive Manufacturing (AM) with the consisting constantly evolving technologies is a particularly popular research area. Based on the shape forming freedom, size, shape, and topology optimization techniques can be validated by AM produced parts. However, in every manufacturing process, AM also has some adverse inherent properties. One and maybe the most significant optimization problem is the mechanical anisotropy caused by the layered structure. In this paper, a simultaneous build orientation and shape optimization method is presented. Both of the approaches are intended to increase the mechanical performance of the produced parts. Shape optimization was accomplished by varying the cross-section of the beam geometries, based on the angle between a PSL section and the characteristic load direction. To test the efficiency and validate the method 2D structures (with relatively small 3rd dimension) and their tensile properties were tested. Based on the results, we can prove that the PSL method works and help to increase the mechanical performance by 19.2% with only 7.8% size increment