## 4 Results and Discussion
### Design of an Innovative Cutting Tool with a Cylindrical Insert  
Based on the concept for using a new shape of cutting insert, the original design of tool was modified. The proposed solution is equipped with a cylindrical cutting element mounted in the holder (Figure 10). The structure developed allows for the rotation of the cutting element in the socket. This ensures that the cutting properties are restored by replacing completely or partially the worn part of the cutting edge. The shape of cutting inserts used allowed for a reduction in diameter compared to commercial solutions of round inserts. The smallest diameter--5 mm--holds a round insert CoroTurn(r) 107 system RCMT 05 02 M0. Based on the design developed, a prototype of a folding tool with a cylindrical element 3 mm in diameter (r\({}_{e}\) = 1.5 mm) was prepared from sintered carbide S30. The body of the tool was prepared from C45 upgraded steel using a section that was 24 \(\times\) 22 mm (Figure 11a). The seat of the tool was located at an angle of \(\gamma_{\mathrm{P}}=-6^{\circ}\), and \(\lambda_{\mathrm{s}}=-6^{\circ}\) was used for the tip of the cutting edge (point C) (Figure 11). The holder was prepared by making a hole with a diameter of 3 mm, the positioning of the hole axis was determined according to the adopted values for angles \(\lambda_{\mathrm{s}}=-6^{\circ}\) and \(\gamma_{\mathrm{P}}=-6^{\circ}\) (Figure 11b); along the axis of the socket, a 22 mm deep cut was made. A hole with a diameter of 3.5 mm was drilled in the tool holder parallel to the axis of the cutting element socket, thus ensuring that the socket could be deformed. Perpendicular to the surface of the cut, a through-going hole was drilled from the outside and then tapped. An M5 countersunk screw with a hexagonal socket was used for clamping. The geometry of the tools was checked using ATOS II Triple Scan with two cameras 2 \(\times\) 5,000,000 pixels (Figure 12). The measurement resulted in a stereo lithography file STL characterized by a dense mesh. The average mesh vertex distance for the surface of the cutting element was 0.08 mm. The measurements were taken using Rhinoceros 7 software. An example of the measuring procedure is presented in Figure 12b for angle a\({}_{\mathrm{P}}\). In order to measure the a\({}_{\mathrm{P}}\) angle, a reference surface was determined, in this case the bottom surface of the tool body. The position of this surface was determined from the position of the extreme vertices of the mesh surface. A group of mesh surface vertices representing the  
Figure 10: A virtual model of the tool ensuring the reproduction of cutting properties using the SEWCE effect and resharpening of the rake surface (RS). A cylindrical element with a length of 35 mm was used. For the proposed tool design, this allows about z = 20 edge resharpenings, considering the part of the element necessary for attachment in the holder. This tool was used for preliminary experiments of turning on a TUD 50 lathe (Figure 13). In the experiments, C45 steel was machined, with a\({}_{\text{p}}\) = 0.2 mm, cutting speed vc = 206.4 m/min, and different feed rates: f = 0.08, 0.19, and 0.27 mm/rev. In the trials, a microscopic method with a marker was used to control the position before and after rotation. Before rotation, the cylinder was unclamped by gripping the protruding part, rotated, and reclamped. Work is underway on a practical solution to control the rotation of the component. Measurements of the surface roughness parameter Ra were performed using a Mahr Gd 120 profilografometer (Figure 14) equipped with a magnetically fixed measuring needle (MFW 250B). Results of the experiment are presented in Figure 15 and compared with theoretical values calculated using Equation (1) and divided by 4. This is the coefficient usually used. Note that the surface roughness decreases for the smallest values of feed.