## 2 Context
Regarding the production of PPEs, face shields may be partially produced by 3D printing (see Figure 3a). In particular, the headband for the face shield may be easily fabricated via FDM and then a PVC sheet is coupled. Depending on the design, some other elements may also be required, for example, elastic rubber. Face shields protect any individual from direct contact with large droplets in the short distance (coughs or sneezes), in addition to prevent physical contact with contaminated hands (see Figure 3b). This phenomenon is known as cross-contamination [24]. Figure 2: Number of positives cases with a PCR test in Castilla-La Mancha between 16 March and 4 May 2020. The UCLM personnel involved in this project used 3D printers located in each of the four campus sites (Albacete, Ciudad Real, Cuenca, and Toledo). These printers had been used mostly for teaching tasks such as laboratory demonstrations in addition to research activities or projects involving Industry. Consequently, the number, distribution, and specifications of the 3D printing systems were rather heterogeneous, which resulted in asymmetric capabilities. Forty-nine 3D printers were relocated from UCLM centers (faculties and research institutes) to some of the volunteers' places to operate during the confinement. On the other hand, 16 industrial systems were used at the 3D printing lab at the Renewable Energy Research Institute ([[https://www.uclm.es/centros-investigacion/ier](https://www.uclm.es/centros-investigacion/ier)]([https://www.uclm.es/centros-investigacion/ier](https://www.uclm.es/centros-investigacion/ier))) in Albacete as those printers could not be moved and hence special permission was granted to some researchers to fabricate PPEs. Table 1 shows the distribution of the UCLM members, collaborating in the initiative, as well as the distribution of resources throughout the region. Undoubtedly, this dispersion of human and material resources in different geographical locations made the initiative hard to coordinate. This was a key issue, as each maker (a maker is a person who prints manufactured objects using a 3D printer; in this case the 3D printing lab in Albacete will also be included as a maker, though it could be considered as a fabrication lab), or fabrication unit was relevant within the network. The availability of each maker may vary as a consequence of different personal conditions such as teaching activities, research commitments, or family obligations. As mentioned above, the 3D printing systems covered a wide range of specifications, from DIY (Do-It-Yourself) kits to industrial models, which implied rather diverse production rates and PPEs with different properties (aesthetic, mechanical, etc). To summarize, the human resources and the equipment were rather heterogeneous and scattered in a rather vast region. Therefore, it was highly demanded to find out how to maximize the production capacity and define an efficient system to answer the requests in the shortest period of time. This further highlighted the need to use customized technology to facilitate the coordination among the volunteers and to ensure the delivery to the end-users. Customized technology implies a digital innovation and transformation, and is related to new services, new platforms, or even new business models in a given context [25]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Campus** & **Collaborators** & **Number of Printers** & **Pinters Location** \\ \hline Albacete & 7 & 20 & 4 at homes \\  & & 16 at 3D printing lab \\ Ciudad Real & 30 & 28 & All at homes \\ Cuenca & 7 & 7 & All at homes \\ Toledo & 11 & 10 & All at homes \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Distribution of human and material resources at the University of Castilla-La Mancha (UCLM). Figure 3: (**a**) Example of a face shield manufactured with 3D printing and (**b**) cross-contamination. In addition, the UCLM must address some further issues:  
* Promotion of the initiative throughout the region to reach all potential users requiring PPEs.