## 4 Results
### Opportunities and Challenges of DSP  
In Question 4 (Appendix A, Table A1) that explores which opportunities of DSP are the most significant (5 = highest), according to Table 6, the highest score was reached by parts on demand production (4.2 out of 5.0), the second highest by faster production with DSP compared to conventional spare parts production (3.75 out of 5.0), followed by digital storage (3.6 out of 5.0).  
Taking the Shapiro Wilk and Chi-square tests into consideration, the aspect of 3D printing inside a company's supply chains does not have an effect on the overall normal distribution of participants' answers for part-on-demand production, outsourcing, and crowdsourcing and a faster production is achieved when applying DSP compared to conventional manufacturing. The Mann-Whitney test (Appendix A, Figure A1) indicates that outsourcing and crowdsourcing has a significantly higher relevance for micro- (mean 3.13) than for medium-sized companies (1.5; \(p=0.014\)). Moreover, digital storage as an opportunity offered by DSP is considered as more important for large (mean 4) than for medium (mean 2.17; \(p=0.011\)) as well as for micro (mean 4) than for medium-sized companies (mean 2.17; \(p=0.003\)). This aspect is also relevant for the comparison of 3D printing usage within supply chains: Companies having 3D printed components in their supply networks (mean 4.11) evaluate the digital storage as more crucial than companies without additively manufactured components in their companies' supply chain networks (mean 3.1; \(p=0.015\)).  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Economic barrier** & **Mean** & **CI** & **Median** & **SD** & \begin{tabular}{c} **SW GD** \\ **Printing Use** \\ \end{tabular} & \begin{tabular}{c} **SW (Number)** \\ **of Employees** \\ \end{tabular} & \begin{tabular}{c} **\(\chi^{2}\) **GD** \\ **Printing Use** \\ \end{tabular} & \begin{tabular}{c} **\(\chi^{2}\) **(Number)** \\ **of Employees** \\ \end{tabular} \\ \hline \begin{tabular}{c} Costs for DSP are much higher \\ compared to conventional \\ spare parts production \\ \end{tabular} & 3.39 & 3.02–3.77 & 4 & 1.37 & 0.88 (\(p=0.000\)) & 0.88 (\(p=0.000\)) & 2.55 (\(p=0.77\)) & 13.47 (\(p=0.86\)) \\ \hline \begin{tabular}{c} Investment costs to establish \\ DSF are supposed to be \\ extremely high \\ \end{tabular} & 3.37 & 3.00–3.73 & 4 & 1.36 & 0.90 (\(p=0.000\)) & 0.90 (\(p=0.000\)) & 8.47 (\(p=0.13\)) & 21.32 (\(p=0.38\)) \\ \hline \
\begin{tabular}{c} Skills of employees are \\ not sufficient \\ \end{tabular} & 2.98 & 2.57–3.39 & 3 & 1.46 & 0.92 (\(p=0.002\)) & 0.92 (\(p=0.002\)) & 7.12 (\(p=0.21\)) & 17.09 (\(p=0.65\)) \\ \hline
\begin{tabular}{c} Current supplier contracts \\ are binding \\ \end{tabular} & 2.29 & 1.90–2.68 & 2 & 1.45 & 0.92 (\(p=0.001\)) & 0.92 (\(p=0.001\)) & 4.35 (\(p=0.50\)) & 11.09 (\(p=0.94\)) \\ \hline \hline \end{tabular}
\end{table}
Table 5: Ranked economic barriers of DSP, N = 50; CI = confidence interval, SD = standard deviation, SW = Shapiro Wilk, \(\chi^{2}\) = Chi-squared test.  
Outsourcing and crowdsourcing could play a more important role for micro companies, due to their low number of employees and focus on niche tasks, which doesn't allow them to cover new tasks that easily. The digital storage is more important for large companies because they must store a larger number of products themselves. Companies that already use additively manufactured components within their supply chains appreciate digital storage as an opportunity. Part-on-demand production has a direct positive impact on decreased storage costs. If reliable part-on-demand production is guaranteed, this opportunity is significant for manufacturing companies, releasing large resources of tied capital.