# Experimental Comparison of Fastener Implementation Approaches in Fused Deposition Modeling
## 3 Results and Discussion
Samples with 10% have 2.71 Nm torque strength, and samples with 40% infill have 3.71 Nm torque strength. Type II samples show the weakest design for the torque test, with 1.79 Nm for 10% infill samples, 2.21 Nm for 20% infill samples, and 3.7 Nm for 40% infill samples. The results of the torque test of the type III samples are 2.39 Nm for 10% infill samples, 2.73 Nm for 20% infill samples, and 4.21 Nm for 40% infill samples. Figure 8.3 Flexural test results of samples. The results reveal that type La has similar characteristics in terms of tensile and torque tests, showing a minor relation to the infill ratio. By analyzing all three test results, the strength of type I.b is directly related to the infill ratio. In order to compare the costs of the samples produced in the study, printing times and amounts of raw materials used were compared. The used filament and approximate times for manufacturing were calculated by slicing software and are given in Figure 8.4 Type La and type I.b samples consume the same amount of material, 110 g, 133 g, and 181 g with 10%, 20%, and 40% infill, respectively. The type II and type III samples use almost the same material, both more than type I, but with a difference of less than 2%. The type II samples use 111 g, 135 g, and 182 g of PLA+, and type III samples use 110 g, 135 g, and 182 g.  
The manufacturing times for type La and type I.b samples are 48 min, 70 min, and 99 min, respectively, and for type II, they are 52 min, 72 min, and 102 min. To complete the production of type I.a and type I.b samples, inserts must be installed after the printing process. This process needs to be performed manually and takes about 4 min per sample. Type II samples also need some work after the printing process. The entrance of the nut cavity needs to be cleaned of supports or any debris, and a nut must be installed afterwards. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Type**} & **Infill** & **Material** & **Print Time** & **Postprocess** & **Total Time** & **Average** \\  & **Ratio (\%)** & **Used (g)** & **(min)** & **Time (min)** & **(min)** & **Strength (N)** \\ \hline \multirow{3}{*}{Ia} & 10 & 109.96 & 48 & & 52 & 301 \\  & 20 & 133.24 & 70 & 4 & 74 & 370 \\  & 40 & 181.37 & 99 & & 103 & 428 \\ \hline \multirow{3}{*}{Ib} & 10 & 109.35 & 48 & & 52 & 502 \\  & 20 & 132.85 & 70 & 4 & 74 & 701 \\  & 40 & 180.97 & 99 & & 103 & 1080 \\ \hline \multirow{3}{*}{II} & 10 & 111.34 & 50 & & 56 & 435 \\  & 20 & 135.48 & 72 & 6 & 78 & 594 \\  & 40 & 181.98 & 102 & & 108 & 885 \\ \hline \multirow{3}{*}{III} & 10 & 110.04 & 51 & & 51 & 547 \\  & 20 & 134.63 & 72 & 0 & 72 & 779 \\ \cline{1-1}  & 40 & 181.85 & 98 & & 98 & 957 \\ \hline \end{tabular}
\end{table} 
Table 1: Production time and material consumptions per piece. Figure 13: Torque test results of samples. The total of this process takes about 6 min per sample if there is no problem with the support structure. Cleaning the part could take time, or the part could even be scrapped if somehow the support structure is unsuccessful. Type III, on the other hand, does not need any processing after printing, meaning that the print time is also the total time. The total times for type III samples are 51 min, 72 min, and 98 min, respectively. There was no significant difference between the active printing times of the printer and the raw materials used. However, when postprocess processes were included in the total production process of the part, it was determined that the design produced by placing nuts during printing was advantageous in terms of time and material consumption. Furthermore, type III can be manufactured semi-automatically or automatically. In semi-automatic mode, the printer pauses when the fastener needs to be installed, and after installation, the printing process continues. In automatic mode, a fastener is installed by a hybrid printer, and no human interaction is needed while printing. This method is less sensitive to the human error factor, even in semi-automatic mode.