## 2 Materials and Methods
### Design of a High Resolution and Low Cost DLP Printer  
The use of better-quality elements directly influences the final price of the printer, so the proposal of this article is to develop a high resolution DLP printer, but whose price is equal to or lowers than the low cost models existing in the market. It is also intended that the printer be open-source, so that any artistic workshop can access the manufacture and modification of it, without additional costs.  
DLP printers have traditionally been more expensive than FDM printers; however, in recent years, there have been open-source proposals for this type of printer, as well as low-cost proprietary models. Among the open-source initiatives, the one carried out by [PERSON], creator of the Prusa3 FDM printer, stands out. The printer Prusa3 has been, for years, the printer selected as a gateway in the world of digital manufacturing, since it combines a low price with the ability to manipulate and improve the printer itself [11]. In 2018, Prusa Research launched the Prusa SL1 3D resin printer (DLP) with the same philosophy of low cost and open source of its FDM models. This printer is equipped with a high-resolution LCD panel (4K) and its current price is 1699 euros, or 1399 if you buy the kit to assemble it yourself (https://www:prusa3d.es/original-prusa-sl1/ accessed on 31 March 2021). On the other hand, there are resin printers that, despite not being open source, can be considered very low cost and, therefore, an interesting option for small art workshops. Among this type of printers is the Wanhao Duplicator 7, manufactured by Wanhao in China. This company, of recent appearance, since it began to sell out of China in the year 2012, has as the main characteristics of its low price and acceptable qualities. In particular, the Wanhao Duplicator 7 model can be obtained for around 500 euros and offers a 2K LCD panel and better resolutions than any FDM printer.  
Taking as reference these two options of 3D printers, the Prusa SL1 as an open-source model and the Wanhao Duplicator 7 as a low-cost model, we intend to design an open-source printer that combines both working philosophies, the high resolution of the first and the low cost of the second. To do this, a design is proposed that allows the printer to be built, using methods that can be replicated by any user at a very low cost. Among  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Resolution** & **Low Cost 3D Printer FDM** & **Low Cost 3D Printer DLP** \\ \hline Resolution X, Y & 400 microns & 40 microns \\ \hline Resolution Z & 50–300 microns & 35–50 microns \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparing the resolution of the FDM (Fused Deposition Modeling) and DLP (Digital Light Processing) 3D printers.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Estimated Resolution** & **DLP 3D Printer FabLab ULL** \\ \hline Resolution X, Y & 30 microns \\ \hline Resolution Z & 20–25 microns \\ \hline \hline \end{tabular}
\end{table}
Table 2: Expected resolutions of 3D printer designed.  
the chosen design options, a repository of 3D pieces of our design will be created to print in PLA with 3D printers of the FDM type. A list of prepared pieces will also be made for its manufacture by cutting machine, free control software will be chosen, and finally, the printer will be provided with low-cost open-source electronics such as Arduino. However, and in order to achieve higher resolution and, therefore, minimize the effect of the laminar texture, the printer will be provided with a 4K LCD panel, a 0.9 degree Nema17 stepper motor and a precision ball screw.  
For the design of the first functional prototype, the components of the printer have been divided into several categories: parts for 3D printing, parts for laser cutting, electronic components, and mechanical parts purchased. In Figure 2 you can see an image of the CAD (Computer Aided Design) design of the printer.