## 3 Results and Discussion
### Results of Measuring the Accuracy of Dimensions and Shape of the Manufactured Models  
The geometry of the reference component was developed in such a way that it was possible to determine the influence of the tested parameters of the FFF additive manufacturing process on selected indicators of technological quality assessment. In Figure 10, the reference plane is marked in red, against which the angle of perpendicularity of cylindrical geometries (cylindrical openings and protrusions) marked in green was measured. To determine the plane during measurements on the coordinate measuring machine, points were recorded, which were then averaged, thus obtaining the plane. Cylinders were measured by recording points along the circumference at three heights, and then the result of each measurement was averaged to indicate the average value of the cylinder diameter. Figure 11 contains charts presenting obtained measurements results of the average deviation of the outer diameter of cylindrical protrusions relative to the nominal diameter (Figure 11a) and the average deviations of the perpendicular angle of the cylindrical protrusions axis relative to the reference plane (Figure 11b). Figure 9: Side surface roughness profiles recorded by stylus profilometry for selected models produced with three different layer heights: (**a**) profile of sample S1, layer height 0.12 mm, fill rate 30%; (**b**) profile of sample S4, layer height 0.16 mm, fill rate 30%; (**c**) profile of sample S7, layer height 0.20 mm, fill rate 30%. Each of the measured geometries was characterized by dimensions smaller than the specified ones, which is due to the accuracy of the print head positioning system during the application of individual layers of material and the thermal shrinkage of PLA. The results of the measurements show that the models with a fill rate of 50% (samples S2, S5, and S8) were characterized by the most accurate representation of the outer diameters of the cylindrical protrusions (dimension deviation ranges from \(-\)0.033 to \(-\)0.061 mm). In the case of angular deviation, no correlations can be found, except for the occurrence of an angular deviation significantly larger than the other models for sample S3 (\(-\)1.505\({}^{\circ}\)). This  
Figure 11: Charts showing the obtained measurement results: (**a**) average deviation of the outside diameter dimension of cylindrical protrusions from the nominal diameter; (**b**) average deviation of the perpendicular angle of the cylindrical protrusion axes relative to the reference plane. Figure 10: Measured geometric features marked on the isometric view of the 3D CAD model of the reference component: the red color indicates the reference plane against which the perpendicularity of the cylindrical geometries marked in green was measured. could be due to the occurrence of an interference in the additive manufacturing process, such as vibration of the base, unsticking of the model from the working table during the process, or deformations occurring due to cooling and solidification of PLA. It is also worth noting that the samples produced using a higher layer are characterized by larger diameter deviations of about 0.01 mm compared to the values obtained with layer heights of 0.12 mm and 0.20 mm. Figure 12 shows the results of coordinate measurements for the openings diameters of the individual samples, with Figure 12a plotting the average deviation of the hole's inner diameter dimension against the nominal diameter and Figure 12b plotting the average deviation of the perpendicular angle of the openings axes relative to the reference plane. For the openings (as in the case of cylindrical protrusions), the diameters measured on the models manufactured by the FFF method are characterized by smaller values with respect to the designed nominal dimension.