# Application of 3D Imaging for Analyzing the Chip Groove Shapes of Cutting Inserts
## 3 Results and Discussion
This was due to the use of notch reinforcement on the cutting edge against wear. In general, the depth of the chip groove was about half that of the SF breaker (the difference between the bottom of the chip groove and its top was about 200 \(\upmu\)m). The analysis of the results showed a variability in the shape of the chip-former profile as a function of the depth of cut. For small depths of cut (\(a_{p}\) = 0.1 mm) for both inserts tested, the shapes of the designated surface profiles were flattened and located highest in relation to the insert base plane. This was due to the value of the rake angle of the rake face of \(\gamma\) = 15\({}^{\circ}\) for the cutting tools analyzed. On the other hand, the lengths of the designated profiles depended on the value of the angle \(K\). The highest values of profile lengths were obtained for the angle \(K\) = 90\({}^{\circ}\) (for example, the profile length for the depth \(a_{p}\) = 0.1 mm was more than twice as large as the profile length for \(K\) = 60\({}^{\circ}\)). The shape of the chip-breaker profile (visible convexity and elevation angle) was fundamentally changed from a depth of \(a_{p}\) = 0.25 mm. Thus, chip formation during machining can be difficult in this area of the cutting edge. The full shape of the chip breaker with its large depth and level difference was visible for depths of cut above \(a_{p}\) = 0.5 mm. This was particularly noticeable for the SF insert. Figures 5 and 6 show examples of measurements of the theoretical chip contact length with the rake face of the insert. The _Lch_ value was measured along the profile of the chip retractor. The results indicate a significant influence of the major cutting-edge angle \(K\)  
Figure 4: Determination and measurement of the shape of the SF chip-former profiles. (**a**) Determination of the breaker profiles for the insert with the major cutting-edge angle \(K\) = 60\({}^{\circ}\). (**b**) Determination of breaker profiles for inserts with \(K\) = 90\({}^{\circ}\). (**c**,**d**) Dimensions of the SF chip-former profiles for \(K\) = 60\({}^{\circ}\) and \(K\) = 90\({}^{\circ}\). In the case of an insert with the SF chip former, for an angle of \(K=60^{\circ}\), the length of the chip contact along the chip retractor profile was similar and did not depend significantly on the depth of cut (_Lch_\(\approx\) 0.44-0.39 mm). On the other hand, for an angle \(K=90^{\circ}\) and a depth of cut \(a_{p}=0.1\) mm, the _Lch_ value was more than twice as high. This is due to the flattened shape of the rake face surface of the cutting edge. In this case, theoretically, the chips are poorly susceptible to the curling process and can theoretically move along the entire rake surface. To improve the chip-curling process, the cutting depth should be increased, which would result in a more accurate filling of the chip groove by the chip material and a shortening of the contact between the chip and the tool. Furthermore, for the cutting insert with an SGF chip former, a decrease in the length of contact between the chip and tool was observed for a depth of cut above \(a_{p}>0.25\) mm regardless of the assumed value of the angle \(K\). However, it should be noted that the chip-to-tool contact lengths were larger (about two times on average) than those for the insert with the SF chip former. The variable shape of the profile, and thus the theoretical contact length between the chips and the cutting edge, was due to the convex structure that reinforced the insert structure. It should be added that, in practice, chip forming can be carried out on a shorter section, i.e., on the first concave shape of the chip former. Figure 6 shows an example of the measurements of the theoretically maximum chip displacement area on the rake face and the volume of the chip groove. It has been observed that both the theoretical contact area of the chips with the cutting edge and the volume of the chip former depend on the depth of cut.