## 2 Materials and Methods
During this study, more than 1500 parts were evaluated one by one. The following important facts need to be considered for this evaluation:  
* The range of size, average surface roughness after printing, post-processing, and mechanical/electrical properties, which are considered for categorizing the parts, are subject to change over time, and the presented data are based on the date of writing this paper;
* Current aluminum parts produced by sheet metal manufacturing methods are not considered in this investigation;
* The binder jetting method is also under development for printing aluminum, and it is assumed to be a cost-efficient method because of the significantly high feed rate. However, the technical evaluation of this technology is under investigation in a separate study. In addition, the currently available building size is small, and it does not cover the majority of the GIS aluminum parts;
* The proposed flowchart considers printability, so cost-efficiency is another item that is discussed in Table 5 separately. However, some logic of being beneficial with AM is thought out in Table 4 as well;
* The level of complexity is defined manually and case by case. However, there is a potential to use deep learning to classify the complexity of geometry. Here, a convolutional neural network (CNN) is suggested for this application. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Part** & **Weight (kg)** & **Challenge** & **Decision Based on the Flowchart** \\ \hline
63.9 & 1. & Large part manufactured by casting in a steel mold. & 1. & DED. \\
2. & Multiple threads. & 2. & Hybrid solutions (PBF + machining). \\
3. & Fine surface roughness. & & (PBF + machining). \\
11.6 & 1. & Large part manufactured by casting in a steel mold. & PBF \\
2. & Precise long through hole. & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Number** & **Part** & **Weight (kg)** & **Current Cost with CM Methods (USD)** & **Estimated Cost with AM Methods (USD)** \\ \hline \hline
1 & -176.500 mm & 0.767 & 14.6 & 620 (without threading) \\ \hline
2 & -132.500 mm & 0.370 & 85 & 309 (without machining of gears) \\ \hline
3  
After the feasibility study, it was clear that AM technologies are available for more than 90% of GIS aluminum parts. Although printability is not a problem, one of the most important parameters that limits the replacement of conventional manufacturing (CM) methods by AM is cost. Therefore, as the next step, some of the parts were selected for cost evaluation. The presented cost evaluation has the following considerations:  
* The cost of AM is estimated by the weight of the part, and it is considered to be USD 0.8 per gram for the SLM method and AlSi10 Mg alloy;
* The cost per part with AM is considered as outsourcing to the service provider and without any special contract for large-volume production. The current cost of CM methods is also based on outsourcing to an external supplier but under a large volume production contract;
* There is no re-design consideration, and it assumes the same design for conventional and AM methods. However, the possibility of re-designing for most of the parts was not significant.