This paper presents the results of a theoretical-experimental study on the influence of FDM parameters (height of the deposited layer at one pass Hs and percentage of filling Pu) on the dimensions of cylindrical spur gears made of PLA (shaft diameter d and bore diameter D). In this context, we designed the 3D model of a cylindrical gear with module m= 1 and z= 60 spur teeth, which we used for FDM 3D printing of 27 PLA parts with different values of coating height deposited at a pitch Hs of 0.10, 0.15, 0.20mm and different values 50, 75, and 100% of filling percentage Pu. The 324 values obtained from measuring the diameters d and D of 27 cylindrical spur gears made of PLA and the calculated values of statistical indicators (arithmetic mean, standard deviation, dispersion) were used to determine the dimensional accuracy of the analyzed parts. The study results show that the percentage of filling has a greater influence than the shaft diameter on the dimensional accuracy of cylindrical spur gears made of PLA.

The article presents the results of the technical–economical study regarding the optimization of fused deposition modeling (FDM) parameters (the height of the layer deposited in one pass—L_h and the filling percentage—I_d) for the manufacture of Polyethylene Terephthalate Glycol (PETG) and Acrylonitrile Styrene Acrylate (ASA) parts. To carry out this technical–economical study, was used the fundamental principle of value analysis, which consists of maximizing the ratio between V_i and C_p, where V_i represents the mechanical characteristic, and C_p represents the production cost. The results of the study show that for tensile specimens made of PETG, the parameter that significantly influences the results of the V_i/C_p ratios is the height of the layer deposited in one pass, (L_h), and in the case of the compression specimens made of PETG, the parameter that significantly influences the results of the V_i/C_p ratios is filling percentage (I_d). In the case of specimens manufactured via FDM from ASA, the parameter that decisively influences the results of the V_i/C_p ratios of the tensile and compression specimens is the filling percentage (I_d). By performing optimization of the process parameters with multiple responses, we identified the optimal parameters for FDM manufacturing of parts from PETG and ASA: the height of the layer deposited in one pass, L_h = 0.20 mm, and the filling percentage, I_d = 100%.

This experimental study investigated the influence of FDM 3D printing parameters on the tensile behavior of PET-G-made parts. In this context, 27 test specimens were produced using FDM on the Anycubic 4 Max Pro 2.0 printer with layer heights applied in one pass Lh = 0.10/0.15/0.20 mm and filling percentages Id = 50/75/100 %. All these samples were tensile tested on the Barrus White 20 kN universal testing machine. The experimental results determined maximum tensile strength, elongation percentage at break, and Young's modulus. The two parameters considered, Id and Lh, influence the maximum tensile strength, the elongation percentage at break, and Young's modulus. The findings demonstrated that the filling percentage has a strong influence on the maximum tensile strength and the elongation percentage at the break of the PET-G samples, and Lh has a decisive influence on Young's modulus.

This study presents the results of optimizing FDM 3D printing parameters (layer height deposited in one pass—L_h and filling density—I_d) to enhance the mechanical performance of three-point bending specimens made from PETG and recycled PETG (rPETG). The objectives of the study are to investigate the influence of variable parameters (L_h and I_d) on the three-point bending behavior of additively manufactured specimens by thermoplastic extrusion of PETG and rPETG. It is also aims to optimize the manufacturing parameters to maximize mechanical performance, but also to evaluate the potential of using rPETG in mechanical engineering applications. The materials analyzed in this study are PETG and recycled PETG (rPETG), in the context of promoting the concept of circular economy. Using the QIDI Q1 Pro 3D printer, and the variable parameters of FDM, L_h = (0.10; 0.15; 0.20) mm and I_d = (50; 75; 100)%, 90 three-point bending specimens (45 from PETG and 45 from rPETG) were additively manufactured. To determine the mechanical strength characteristics under three-point bending stress, all 90 additively manufactured specimens were tested in three-point bending using a Barrus White 20 kN universal testing machine. The maximum bending stress is influenced by the two considered variable parameters of FDM (L_h and I_d), the parameter with the greater impact being I_d. Comparing the results of the maximum bending stresses of the additively manufactured specimens made of PETG and rPETG using the optimal parameters, it was found that the maximum bending stresses are higher in the case of the rPETG specimens, which highlights the potential of using recycled plastics in mechanical engineering applications.

This article presents the results of a study on the influence of Fused Deposition Modeling (FDM) 3D printing parameters on the compressive behavior of test specimens made of PET-G. In this context, 45 test specimens, made by FDM on the Anycubic 4 Max Pro 2.0 printer, were compressive tested on a universal testing machine Barrus White 20 kN, with the height of the layer applied in one pass being Lh = 0.10/0.15/0.20 mm and filling percentage Id = 50/75/100%. The two considered variable parameters, Lh and Id influence the compression resistance of the PET-G parts, with Id having a more significant influence. The scope and novelty of this work is to find the optimal parameters for maximum compressive strength (Cs) of PET-G samples made of FDM.

The paper brings forward the results of a study on the compression test of 28 lattice structures made of PLA by FDM, with the height of the deposited layer at a pass of Hs = 0.20 mm and 50% filling percentage Pu. The 28 samples were made on Anycubic 4 Max Pro 2.0 the 3D printer, considering 7 filling patterns: Grid, Tri-hexagon, Octet, Triangles, Cubic subdivision, Gyroid, and Cross 3D for each type of lattice structure. The dimensions of the specimens, before and after the compression test, were determined using the DeMeet 3D coordinate measuring machine. In this context, a minimum printing accuracy value of 98.98% and a maximum deformation value of 57.70% were recorded for the lattice structure corresponding to the Triangles fill pattern. For the same Triangles type lattice structure, the highest average maximum compressive force of 87.32 kN was obtained. The maximization of the ratio between the use value and the production cost, one of the fundamental technical-economic principles of value analysis, was obtained for the lattice structure corresponding to the Cubic subdivision filling model.