## 4 Conclusions  
The transition of 3D-printing from rapid prototyping to rapid fabrication has brought into attention the requirements regarding the dimensional accuracy and the properties of the prints and, moreover, the productivity of the additive manufacturing processes.  
In case of the FDM method, the printing speed is a widely analyzed process parameter, that can lead to shorter production times. Simultaneous printing of identical parts could be as well a solution in this regard, if the reproducibility of the process in respect to the dimensions and the properties of all simultaneous printed products is ensured.  
The obtained results led to the conclusion that the dimensional accuracy of PLA prints is significantly influenced by the printing scenario, the position of the specimens on the build plate and the filament color, as proven by ANOVA statistical analyses. The effect of the printing scenario and the specimens' positions is less important than that of the filament color.  
Thus, simultaneous printing of three and respectively five specimens slightly enhanced the dimensional deviations (increase of the cross-section area by up to 3.93% compared to the cross-section area of the individual printed specimen) and led to some differences (up to 3.65%, depending on the filament color) between the cross-section area of the specimens printed simultaneous in different positions of the build plate.  
Regarding the effect of the PLA color on the dimensional accuracy of the specimens, the experiments revealed the existence of differences up to 5.71%, for the same printing scenario, regarding the cross-section area of different colored specimens (red and grey, batch of 3 specimens).  
The tensile strength of FDM printed PLA specimens is influenced by the printing scenario, the position of the specimen on the build plate and the filament color, too. Also regarding the prints' strength, the effect of the printing scenario and the specimens position is less important than that of the filament color.  
Thus, when increasing the number of simultaneous printed specimens up to five, the mean value of the tensile strength of same colored specimens, printed with the same scenario, decreased slightly by up to 3.63% in relation to the UTS of the individually printed specimen (grey PLA), under the condition of up to 5.31% non-uniformity of the UTS values of different positioned prints of the same color (natural PLA).  
On the other hand, the maximum differences between the mean values of the tensile strength of different colored specimens, printed with the same scenario, were found to be equal to: 7.70% for individual printing (between the UTS of the grey and red specimens), 10.45% for three specimens printed simultaneous (between the UTS of the black and red specimens) and respectively 7.34% for five specimens printed simultaneous (between the UTS of the grey and red specimens).  
As an overall conclusion, one may summarize that simultaneously printed specimens could be produced only if a variation up to 4% in respect to the dimensional accuracy, respectively up to 5.5%, considering the UTS, are acceptable for later application. The filament color has to be taken into account as a possible influencing factor, as well.  
Conceptualization and methodology: D.F., V.C. and G.M.; data curation and investigation: V.C., R.R.T., G.T., D.F. and N.B.; writing--original draft preparation: V.C. and R.R.T.; writing--review and editing: D.F., V.C., G.T. and G.M.; visualization: V.C.; supervision: V.C. and D.F. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Data Availability Statement: The data presented in this study are available on request from the corresponding author.  
The activities of the two students, [PERSON] and [PERSON], carried out within this research were supported by the Babes-Bolyai University through Special Scholarships for Scientific Activity.  
The authors declare no conflict of interest.