# Comparison of the Wear of Toroidal and Spherical Cutters in Milling and the Impact of Corrosion
## 3 Experimental Results  
Each type of damage will progress or occur in a variety of ways, depending on the milling conditions. As stated in ISO 8688 [29], wear-related damage should be used to evaluate a tool's durability. After processing the five types of surfaces at an angle of inclination of \(15^{\circ}\), the resulting tool wear is shown in Figure 6a for the toroidal cutter and Figure 6b for the spherical cutter. For the spherical cutter, the maximum edge wear length is 4.365 mm, with a maximum width of 0.136 mm, resulting in a total wear area of 0.2716 mm\({}^{2}\). With a maximum length of 2.933 mm and a maximum width of 0.226 mm, the toroidal cutter exhibits wear on the edge, with a wear surface area of 0.27127 mm\({}^{2}\). In this case, the values are very close, with an insignificant advantage on the side of the toroidal cutter. Figure 4: Microscope MM1-200. Figure 5: Positioning the tool for measuring edge wear. Referring to the processing of the five types of surfaces, with a constant angle of inclination of 35\({}^{\circ}\), the tool wear situation is as follows. Figure 7a shows the wear of the toroidal tool, which has a maximum length of 2.65 mm and a maximum width of 0.402 mm with an area of 0.44564 mm\({}^{2}\). Figure 7b shows the wear of the ball tool, having a length of 4.304 mm and a maximum width of 0.16 mm, with the total wear area being 0.35776 mm\({}^{2}\). In this case, the toroidal cutter achieves 0.08788 mm\({}^{2}\) more wear on the tool edge than the ball milling cutter. Surface processing at the 55\({}^{\circ}\) tool tilt angle results in tool edge wear, as shown in Figure 8. Figure 8b shows the wear of the spherical cutter with a maximum length of 4.463 mm and a maximum width of 0.194 mm, resulting in a wear area of 1.194 mm\({}^{2}\). In Figure 8a, the wear of the toroidal cutter is shown as having a maximum length of 2.932 mm and a maximum width of 0.255 mm, resulting in a wear area of 0.48123 mm\({}^{2}\). High tool wear at a 55\({}^{\circ}\) tilt angle, as shown in Figure 9, is the combined result of increased cutting forces, uneven stress distribution, excessive heat generation, and suboptimal chip evacuation dynamics. These conditions amplify the abrasive and thermal wear mechanisms. Figure 8: Comparison of spherical and toroidal tool wear during machining at an angle of 55\({}^{\circ}\). (**a**). Toroidal milling; (**b**). Spherical milling. Figure 6: Comparison of spherical and toroidal tool wear after machining at 15\({}^{\circ}\) angle. (**a**). Toroidal milling; (**b**). Spherical milling. Figure 7: Comparison of spherical and toroidal tool wear during machining at 35\({}^{\circ}\) angle. (**a**). Toroidal milling; (**b**). Spherical milling. At a tilt angle of 55 degrees, the axial component of the cutting force increases significantly when compared to smaller angles (e.g., 15\({}^{\circ}\) or 35\({}^{\circ}\)). This results in greater pressure on the cutting edge, amplifying abrasive wear and the risk of microcracking. Additionally, at 55 degrees, the contact between the tool and the workpiece becomes more concentrated on a portion of the cutting edge, leading to localized wear. This is accentuated by the angle that does not optimize the uniform distribution of chips, unlike smaller angles, which can facilitate more efficient chip evacuation. The spherical cutters show, on average, 38% more wear than the toroidal cutters when the wear surfaces of the two cutter types are compared. Concentrated contact, high temperatures, ineffective chip evacuation, and stronger vibrations are all blamed for this increased wear. Toroidal cutters achieve a better balance of cutting forces (tangential, radial, and axial components) due to their larger tool-workpiece contact distribution and corner radius. This equilibrium minimizes sidewall wear and chipping by lowering the chance of vibration and focused stress.