## 3 Results
### The 2D Deviation Analysis  
As mentioned above, a study of the lateral deflections has been carried out from the analysis of the perimeter of the designed geometries. Once the manufactured specimens were analysed, the data obtained were processed. When analysing the figures, the first thing that can be seen is a pixelated effect in the case of DLP technology, something that is characteristic of this technology [17] and which is not seen with LCD technology. This effect appears, independently of the geometry and resolution, as can be seen in Figure 7.  
On the other hand, if the images are analysed as a whole, it can be seen that in the case of the LCD technology (Figure 8), regarding the positive and negative geometries, increasing the exposure time slightly improves the accuracy of the corners up to 8 s. If it is increased further, negative effects occur. In the case of DLP technology, similar behaviour occurs (Figure 9), so it follows that exposure times significantly affect figure accuracy. To study the effects more concretely, the perimeter of these figures will be analysed. In order to study these effects, firstly, the main effects graph was obtained for each of the different geometries. This type of graph provides an overview of the influence, or lack thereof, of the factors on the measured variable, in this case, the perimeter (Figure 10). Analysis of the graph shows that the most significant factors are the direction of manufacture and the type of technology used. On the other hand, it is generally observed that the exposure time has practically no effect on the measured perimeter. Figure 6: Image of the recharge effects. (**a**) DLP technology in lowest resolution; (**b**) LCD technology in lowest resolution. Figure 7: Image of the pixelation effects. (**a**) LCD technology; (**b**) DLP technology. Taking into consideration the manufacturing direction factor, there is a clear trend showing that the manufacture of shafts is able to reproduce average values of the perimeter close to the design perimeter. On the other hand, the parts manufactured as hollows significantly exceed the design values, regardless of the exposure time applied and the manufacturing equipment used. Likewise, it can be seen that the parts manufactured with LCD technology present mean experimental values of the perimeter closer to the design values, while those manufactured with DLP technology far exceed the values of the established model. It can also be seen that the average of the perimeter values obtained exceeds the theoretical design perimeter, without taking into account any of the aforementioned factors. It can be seen that the mean value of the perimeter measured in all experiments is 24.2122 mm, while the theoretical value of the designed perimeter is 24 mm. The relative error between the two measurements is 0.884%. It can be concluded that the experimental results of the average circumference obtained were above the design values, i.e., parts with larger dimensions have been manufactured, although the relative error between both values is very small. These graphs provide some information about the main effects of the proposed factors on the selected measurements. However, in order to correctly establish the significant factors of an experiment, it is necessary to carry out an ANOVA test. With this analysis, the actual significant factors of a study are obtained. The common ANOVA test has a confidence level or interval of 95%, where \(\alpha=0.05\). Table 4 shows the \(p\)-values obtained for each factor, with the aim of establishing those that are significant in this study. Figure 8: Image of the square test specimen obtained with LCD technology. Figure 10: Graph of main effects on perimeter for square geometry. Figure 9: Image of the square test specimen obtained with DLP technology. It can be seen that the significant factors in the three geometries correspond to those listed above in the main effects plots.