الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 156 |  |  |
| | | from | 156 | | |
Abstract
The vast progress in modern applications requires innovative production and manufacturing methods. 3D printing additive manufacturing method is the last witness of that progress. 3D printing additive manufacturing has been proposed as a production method with high-profit margins and high flexibility to produce complex products. As a result of the appearing additive manufacturing technique, it becomes necessary to evaluate the parts fabricated by such techniques in the mechanical field, especially on spur gears. Therefore, the effect of 3D printing process parameters (infill pattern – infill density – layer height – line width – shell thickness – printing temperature – printing speed) on the mechanical properties has been studied to obtain the maximum tensile strength and modulus of toughness to design the spur gear. Besides, the effect of infill pattern (Grid, Triangles, and Concentric) and infill density (20%, 60%, and 100%) parameters have been studied in each dry and under lubrication modes. Furthermore, two similar spur gears one of them is printed spur gear with optimum values of 3D printing parameters and the other is steel gear have been tested to estimate their vibration behaviors under different speeds (70 - 120 – 500 – 1300 – 1900) RPM. In addition, the study of the generated stresses, strains, and deformation on steel, printed PLA+, injected PLA+ spur gears soft models have been performed under the same conditions using the finite element method. The experimental results revealed that the highest value of tensile strength and toughness can be obtained at infill density of 100%, concentric infill pattern, layer height of 0.1 mm, a line width of 0.8 mm, shell thickness of 0.8 mm, printing temperature of 215˚C, and printing speed of 60 mm/sec. The highest and lowest values of friction coefficient were achieved for the Grid sample with 100% infill density and without lubrication, and the triangles sample with 20% infill density and with lubrication, respectively. The lower friction coefficient is
linked with the lower infill density (20%) because of the lower contact surfaces. This could be attributed to the lower contact surfaces which are subjected to friction. And the highest and the lowest values of wear rates were took placed in the cases of Grid sample with 20% infill density and without lubrication, and Grid sample with 20% infill density and with lubrication, respectively. The wear rate behavior is attributed to the formation of the protective film which safeguards the surface from damage and wear. In the case of a low speed of 70 RPM, the optimum printed gear and steel have almost the same amplitudes and noises at the same frequencies. On the other hand, In the case of other speeds (120-500-1300- 1900) RPM, there is a noticeable effect on their amplitudes and noises at the same frequencies. The maximum stresses, strains, and deformation generated on the printed gear have been estimated theoretically and a comparison between the spur gears fabricated by different routes has been carried out.