## 3 Results
### Experimental Temperature Measurement  
The drilling tests are described exemplary on the basis of test \(V001\) from the experimental design table, shown in Figure 11. It can be seen that the feed force initially drops since a force opposite to the drilling direction prevails due to the cooling lubricant pressure. Afterwards, a constant force prevails on the tool until it hits the workpiece and the feed force increases. The temperature rise starts at approximately \(t\) = 22.5 s with the start of the drilling process. Prior to this, there is a slight temperature increase of \(dT\sim\) 3 K due to the supply of the drilling oil. Subsequently, the temperature rises within approximately \(t\) = 22 s to a constant value of \(T_{1}\) = \(T_{3}\) = 320 K and \(T_{2}\) = 323.5 K, respectively. As the drill-head begins to exit the workpiece, the temperature rises further. Most noticeable is the temperature rise \(T_{3}\) of S3. The sensor S3 is placed with an offset to the rear on the outside of the cutting edge. The drilling oil conveyed through the shank is no longer transported back over the cutting insert due to the absence of the bore ground, but sprays straight out of the tool into  
Figure 10: CEL simulation results, \(\
u_{c}\) = 80 m/min, \(a_{p}\) = 0.05 mm, mass scale MS = 10\({}^{5}\), temperature \(T\) /K.  
With the approach of temperature measurement via a thermocouple, the absolute temperature of the outer egde of the cutting insert is to be measured. The slow reaction time of the thermocouple is to be relativized by the fact that the thermocouple measures the temperature from the start of the process and so it can gradually heat up with the workpiece, as is shown in Figure 15. In order to measure the temperature as close as possible to the effective point, the thermocouple is machined along with the cutting edge. By the time the thermocouple gets hit by the tool, the temperature either falls, because the thermocouple is pressed out by the cooling lubricant, or the sensor no longer supplies data, as the connection between the two materials is machined.  
Figure 12: Effective area diagram of the temperature measured with S2.  
Figure 13: Chip formation of V003 and V009.  
Based on the process parameters and the sampling rate of the temperature, the maximum occurring distance \(s\) between thermocouple and cutting edge can be calculated. This prevails when the cutting edge is slightly less than one time step from the sampling distance of the thermocouple before it is cut. With a set sampling rate of 10 kHz and due to the inertia of the thermocouple, the sensor values are sampled more frequently than new values are written from the sensor. New measured temperature values can be obtained every \(t_{delay}=0.16\) s. With  
\[s=n\times t_{delay}\times f. \tag{8}\]  
the maximum distance where the last temperature is written at is 0.003 mm \(<s<0.19\) mm. For the investigation of the temperature at the different process parameters from the experimental design, it was also possible to generate an effective area diagram. The effective area diagram from Figure 16 shows, in principle, the same behavior as the temperature measured via the resistance sensors. The measured temperature increases with increasing feed rate. Increasing the cutting speed also leads to an increase in temperature. Here, the impact of the feed rate is not as high as with the sensoric SLD-tool, while the cutting speed has a higher influence on the height of the temperature.  
Figure 14: Effective area diagram of the heat rate of S2.  
Figure 15: Temperature measurement via thermocouple V001.