PSI - Issue 37

Mohammed Zwawi et al. / Procedia Structural Integrity 37 (2022) 1057–1064 Mohammed Zwawi/ Structural Integrity Procedia 00 (2019) 000 – 000

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Figure 1 : 3D printed actual Eye grab hook with different cross sections (a) model “OR”, (b) model “TK”, (c) model “AD”, (d) model “FS”, and (e) mod el “AS”.

Figure 2 : Eye grab hook models: (a) model “OR”, (b) model “TK”, (c) model “AD”, (d) model “FS”, and (e) model “AS”.

Figure 3 : Eye grab hook dimensions in mm for: (a) model “OR”, (b) model “TK”, (c) model “AD”, (d) model “FS”, and (e) model “AS”.

2.3 Printing variables The eye grab hooks were fabricated at room temperature by a commercial printer using the FDM technique. The printer was a Creality 3D Ender-3, which is completely open sourced — all files and relevant source code are available online. The nozzle temperature and diameter were 255 °C and 0.4 mm, respectively. The filament roll diameter was 1.75 mm. The Cura 4.6.2 software was integrated with CAD SolidWorks ® software to operate the 3D printer. The printer used an FDM technique that heats the filament to a molten state through a single-heated nozzle and then extrudes the molten filament and deposits it on a build plate, referred to as the platform. The nozzle had three degrees of freedom that followed the coordinates in the G-code file, which is part of the CAD model. The molten filament deposit process was set layer by layer on the build plate over and over until the desired prototype was produced. The layers cooled on the platform, hardened, and stuck together to form a single mass part (Algarni, 2021; Mwema & Akinlabi, 2020). The 3D printing parameters were fixed, as shown in Table 2 . The hook’s orientation printing was horizontal laying on the build plate. The XY layer (horizontal) resolution is the minimal movement the print head can horizontally move. Note that for simplicity, the material is considered homogeneous and solid since the infill density is 100%,

Table 2: 3D printing parameters

Nozzle diameter XY layer resolution Printing speed Heated bed temp.

0.4 mm 0.1 mm 18 mm/s 110 °C

Nozzle extrusion temp. Infill layer thickness

205 °C 0.12 mm

Infill density

100%

Number of contour layers

6

2.4 Eye grab hook simulation The five eye grab hook models were modeled and simulated in SolidWorks® to determine where the stresses concentrated during the loading process. Two initial boundary conditions were set for all models during the simulation: (1) a fixed pin support in the inner radius of the eye and (2) a stress control force towards the negative y-axis, as in Figure 4(I). The results of the simulation showed a high-stress concentration at the weak points of each eye grab hook