## 1 Introduction  
Drilling is one of the most used processes in cutting technology, whereas using twist drills is the most common drilling method. Despite the advantages of twist drilling tools, such as low-cost and self centering, some applications have extra requirements with respect to surface quality or length-to-diameter ratio of the bore holes. Deep hole drilling is a drilling process, allowing boreholes with large \(l/D\) ratios and a particularly high surface quality. The production of deep bore holes via single-lip deep hole drilling tools utilizes asymmetrical single-edged tool designs. The asymmetrical single-edged drilling tool requires special guidance because of a resultant force coming from the process cutting forces. The guidance outside of the workpiece consists of a drill bush and, depending on the tool length, additional steady state rests. While drilling, the guide pads of the tool, which have a slightly larger effective diameter than the cutting edge, plastifies the wall of the bore hole. That interaction leads to high surface qualities and compressive residual stresses in the subsurface through forming interactions between the tool and workpiece [1, 2]. The main problem producing deep bore holes is a reliable chip removal. Therefore, a cooling lubricant is fed under high pressure through the shaft of the drilling tool. The aim of the cooling lubricant is, on the one hand, cooling down the process and, on the other hand, the chip removal from the chip formation zone. High process temperatures can also affect the marginal zones of the bore hole wall [3]. [PERSON] also simulates the chip removal process from the effective area of the cutting edge of a SLD tool. No sufficient cooling lubricant can be found at the outer edge of the cutting edge [4].  
The temperature in the cutting zones has a significant influence on the deep hole drilling process [5]. In order to determine the temperature directly at the cutting edge, a concept was developed in this work that can be used to derive determination equations from experimental temperature measurement data and simulation results that predict the temperature directly in the cutting zone. These equations can be used for real-time control in the future. Among other things, a sensory tool was used for the temperature measurements, with three PTC sensors integrated here under the cutting insert [6]. In order to investigate the temperature in a two-dimensional state, orthogonal cuts were performed presenting experimental and simulation chip formation, frictional impacts and the resulting temperatures [7,8]. To study the SLD process, several investigations were carried out. Via Lagrangian simulation, thermographic camera and PTC resistance sensors, the thermal as-is state was examined [9,10]. In addition, the influence of the thermomechanical condition on the subsurface during deep drilling was considered. A thermocouple was used to determine the temperatures on the workpiece side at various process parameters. Coupled Eulerian-Lagrangian (CEL) simulations were carried out to compare the feed forces and the residual stress state in the subsurface [11]. Further investigations studying the thermomechanical impact of SLD on the surface integrity concentrates in temperature measurements with thermocouples and a pyrometer and various cooling lubricant strategies [12,13]. Based on this, a temperature determination of the tool cutting edge during the deep drilling process is to be made possible.