# The Simulation Analysis of Cutting Characteristics and Chip Formation Mechanism in Gear Skiving
## 3 Analysis of Cutting Angles and Sliding Speed in Gear Skiving
Therefore, this part of the cutting edge is the most susceptible to wear in skiving tools, while the cutting conditions of the approaching edge are better than those of the recessing edge and top edge. The calculation results of the working clearance angle during the skiving process are shown in Figure 5b. Contrary to the working rake angle, the working clearance angle increases from \(2^{\circ}\) to \(47^{\circ}\) as the tool progresses through the cut. Generally, the working clearance angle is small when the cutting edge cuts into the workpiece and gradually increases as the tool exits the cut. The smaller clearance angle and thinner cutting depth at the cutting-in stage are difficult to form, which leads to wear on the tool flank. The calculated results of cutting thickness during the skiving process are shown in Figure 5c. The variation pattern of cutting thickness matches the simulation results. The cutting thickness starts at zero when the tool first engages the workpiece, gradually increases during the cut, and reaches its maximum when the tool exits the workpiece. The maximum thickness occurs at the edge connecting the top edge and the recessing edge. In conclusion, single-pass skiving completes the entire tooth slot cutting, but the cutting conditions are poorest when the tool exits the slot, leading to tool wear. Therefore, adopting multiple radial feeds during the skiving process can effectively improve tool wear [10]. The results of the calculation of the tool inclination angle during the gear skiving process are shown in Figure 6a. As depicted in the figure, the inclination angle decreases from \(9.4^{\circ}\) to \(-49^{\circ}\) during the cutting process. Generally, negative inclination angles are unfavorable for chip evacuation, thereby affecting the tool's lifespan and processing quality. The figure indicates that the approaching edge has a significantly negative inclination angle when exiting the cut, whereas the top edge and recessing edge also have negative inclination angles but with smaller absolute values. This suggests different chip evacuation rates for the approaching edge, top edge, and recessing edge, with chips prone to compress at the corner between the approaching edge and top edge, negatively impacting tool lifespan and workpiece quality. The results of the calculation of the tangential cutting speed during the gear skiving process are shown in Figure 6b. The variation pattern of tangential cutting speed \(\mathbf{v_{t}}\) is similar to that of the inclination angle. The approaching edge has a high absolute tangential cutting speed when exiting the cut, whereas the top edge and recessing edge have lower absolute tangential cutting speeds, also indicating different chip evacuation rates. Since tangential cutting speed affects chip evacuation, chips are likely to compress at the corner between the approaching edge and top edge, negatively impacting tool lifespan and workpiece quality. The results of the calculation of the normal cutting speed during the gear skiving process are shown in Figure 5c. The normal cutting speed \(\mathbf{v_{n}}\) increases from 453 mm/s at the beginning of cutting to 798 mm/s when exiting the cut, with a wide speed range, shown in Figure 6c. Normal cutting speed is the primary speed component for chip formation, influenced by the tool and workpiece rotational speeds, axis intersection angle, and pitch circle radius.