## 3 Results
### Cooling Wide  
Since no base temperature could be measured for the cooling experiments due to melting of the polymer at higher temperatures, Figure 7 shows the tensile strength of the cooled specimens at a wide cooling distance of 100 mm without a surface for base values. Again, the gradient map represents the results of the cooled samples, while the gray surface reflects the results of the uncooled samples from unmanipulated experiments.  
While the gray surface was spanned across all velocities, the strength values were determined only for samples manufactured at 0.160 m/s without any temperature manipulation through cooling. While these reference measurements were performed at distinctive chosen temperatures, the color map represents the resulting tensile strengths of the manipulated substrate temperatures, obtaining a disordered distribution of the temperatures. As briefly mentioned before, the large distance between the cooling nozzles did not allow for sample manufacturing at substrate temperatures above the melt temperature, and thus, only an excerpt of the original DoE for wide cooling was feasible, since the part size could not be sufficiently reduced to achieve the desired layer times at the given traversing velocities.  
Figure 6: Standard and nominal tensile strength of the heated specimens with the reference tensile strengths for unheated specimens at the same base temperatures and the achieved heated temperatures.  
The surface in Figure 7 and the bar chart results of Figure 8 present that the tensile strength in the transverse direction consistently yielded identical or higher results than those of the unheated counterparts. This was independent of the actual traversing velocity or the resulting substrate temperature for both the single strand and nominal bulk material tensile strength. Based on the unheated specimen, there was a significant reduction in tensile strength below the suggested processing window [12] and thus below the onset of crystallization. However, the temperatures 139 and 131 \({}^{\circ}\)C, which fell below this limit, yielded nearly as high tensile strengths as the hotter samples.  
Similar to the heated experiments, the tensile modulus remained in the range of, but slightly below, most of the target values, as shown in Figure 9. It is also noticeable that there is barely any difference in the values achieved, independent of the actual temperature, even though the reference values drop considerably when manufacturing outside of the process window.  
While no overall cooling effect can be numerically determined without a measurable base temperature, the effect of the final air nozzle was determined between \(-22\) and \(-36\)\({}^{\circ}\)C at 170 \({}^{\circ}\)C as the lowest target temperature and \(-50\)\({}^{\circ}\)C at the highest target temperature of 216 \({}^{\circ}\)C.  
Figure 8: Standard and nominal transverse tensile strength of the cooled specimens at 100 mm cooling distance with the reference tensile strengths for unheated specimens at the achieved heated temperatures.  
Figure 7: Tensile strength of the cooled specimens at 100 mm cooling distance in the transverse direction with the reference tensile strength for uncooled specimens at the final substrate temperature (gray).