## 4 Conclusions
After a careful analysis and consideration of the results, the authors established a series of findings where they all agreed that it was of vital importance to ensure high standards of quality and precision levels were being met for the factors under study. This was found to be vital in order to avoid any influence or effect related to the technological precedence of the elements involved (technological heritage or simply how the tubes or even dies had been produced before). This conclusion was of special importance for the case of the die because in the cold tube drawing process, the resulting diameter of the tubes, their wall thickness, and even their roundness itself, i.e., variables \(y_{2}\), \(y_{3}\), and \(y_{1}\), respectively, highly depend on the die's condition and, as mentioned before, on its precise dimensioning as well. In this regard, the authors also concluded that it was necessary to keep a tight control over the lubrication of the die given the proven potential for it to be statistically and technologically significant in all response variables under study. Another important finding explaining the significance of the factors and their interactions was linked to the single-pass nature of the cold tube drawing process investigated in this paper. This type of approach implied large size reductions, which proved to be significant for the drawing of the tubes, which would otherwise have been realized through a double- or multi-pass approach, a process that, even though it is more time consuming and expensive, usually offers less deviations from the product geometrical specifications. All these conclusions open several more questions to be answered in future research by the authors of this research, while at the same time, they clearly answer the initial question of whether, under the circumstances and factors defined for this research, the single-pass cold tube drawing process is a viable alternative to more expensive and time-consuming multi-pass processes. Further research will focus on analyzing these same factors under the single-pass approach, but also taking into account the recommendations and precautions mentioned above. It is also a goal of the authors to replicate what was conducted in this research under a multi-pass approach in order to compare and set clearly quantifiable differences between both courses of action. At the same time, further research will also cover the analysis of these factors in relation to other relevant response variables that are problematic for industrial practice and science. Conceptualization, M.K. ([PERSON]), L.M., J.B., M.K. ([PERSON]), and D.R.D.S. ; methodology, M.K. ([PERSON]), L.M. and D.R.D.S. ; software, D.R.D.S., M.K. ([PERSON]) and R.S. ; validation, D.R.D.S., M.K. ([PERSON]) and L.M. ; formal analysis, D.R.D.S., M.K. ([PERSON]), L.M. and R.S. ; investigation, M.K. ([PERSON]), M.K. ([PERSON]), J.B. and L.M. ; resources, M.K. ([PERSON]), D.R.D.S., J.B., L.M., R.S. and M.K. ([PERSON]); writing--original draft preparation, D.R.D.S., M.K. ([PERSON]), M.K. ([PERSON]) and L.M. ; writing--review and editing, D.R.D.S., M.K. ([PERSON]), L.M. and R.S. ; visualization, D.R.D.S. and M.K. ([PERSON]); project administration, L.M. and M.K. ([PERSON]); funding acquisition, L.M. All authors have read and agreed to the published version of the manuscript. This work was supported by the Slovak Research and Development Agency under the Contract No. APVV-18-0418. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Acknowledgments: This work was supported by the Slovak Research and Development Agency under the Contract no. APVV-18-0418 (Research on causes of geometrical deviations in the production of seamless tubes and their technological inheritance with emphasis on the shape stability of precision cold drawn tubes using metrological systems). The support and funding are both gratefully acknowledged. The authors declare no conflict of interest.