# Obtaining Various Shapes of Machined Surface Using a Tool with a Multi-Insert Cutting Edge
## 3 Results and Discussion  
### Universal Form Tool for Turning  
The design concept of the form tool presented in Figure 1b was turned into a prototype of a new turning tool. Examples of single profile edges are presented in Figure 4a. All edges have the same rake angle, \(\gamma_{o}=0^{\circ}\), and clearance angle, \(\alpha_{0}=10^{\circ}\). The values of \(k_{r}\) are presented in Figure 4a. Figure 4b visualizes the surfaces machined with the example of the proposed tool. The multi-edge tool holder clamps the single inserts in place with fixing screws. The holder also has adjustment or setting screws along the radial direction for single cutting-edge position adjustment. Assembly of the tool is possible with a set of extra screws for increasing tool stiffness. Radial adjustment of the edge position is therefore possible, while the width depends on the dimensions of the single cutting edge, which in the prototype design is equal to the distance between the screws. The height of the holder was selected for installation on a universal lathe. This innovative solution is registered under a Polish patent [39].  
The virtual model of the form tool as shown in Figure 4b is especially convenient for GKF tool analysis [39]. Changing the surface contour can be achieved by changing the position of the edges or replacing them with other edges. The number of achievable profiles is shown in the relationship (1) and is illustrated in Table 1.  
Figure 3: Screenshot of the _Tool_Shape_ software for insert selection and positioning.  
The setting screws also allow for accurate positioning of the edge in the radial direction. The geometry of the flank, however, must always be checked. The cutting edges were prepared with a rake angle of \(\gamma_{o}=0^{\circ}\), to facilitate the application of the edge and its insertion. These settings are in most cases sufficient for the machining of a variety of materials. The rake angle can be increased by setting the edge above the axis, but care must be taken to maintain the appropriate value of the clearance angle. The prototype tool was manufactured based on the CAD model using individual inserts that were machined from a 10 \(\times\) 10 \(\times\) 60 mm blocks of HSS SW18 steel.  
First, a CAD model of an object with multiple profiles was generated, as shown in Figure 4c, to validate the design performance of the form tool. Turning tests were then conducted on PA4T material at a cutting speed of \(v_{c}=100\) m/min and at a feed rate of \(f=0.067\) mm/rev. A sample outline of a machined surface (Ra = 1.02 m) is presented in Figure 4c. The tests validated that the design and the machined surfaces had the same contours. For the used feed rate, the cutting time was much shorter than for longitudinal turning (about 4 times).  
A significant value of the rake angle was used for wood processing. When using a rake surface made of single edges, this angle can be obtained by positioning the edge above the turning axis. However, the resulting shape of the surface will therefore deviate from the shape of the contour of the cutting edge. Further examples of different shapes (at least in the CAD model) using the same tool must be shown for validation of the universal form tool in the turning operation. A new problem specific for the presented tools, in the field of turning where a common folded rake face is used, is the wear of the edges in the area of contact of neighboring edges of the folded profile. This should be the subject of further research.