## 3 Experimental Results and Analysis
### Influence of Feed on Axial Drilling Force
surface temperature field increases correspondingly with the increase in the feed volume, and the degree of thermal softening of the workpiece material in the process of drilling is increased, and the axial force of plastic deformation of the drilling cap camber decreases, so that the axial force increase in the second stage and the axial force increase in the third stage are consistent. The slope of the increase in the axial force in the second stage and the third stage is close to the same. Figure 12 shows the morphology of the drilling cap and the temperature field when the axial force is maximized at different feeds \(f\). From the temperature field of the bottom surface of the drill cap formation process, it can be seen that the temperature is higher after the feed amount \(f\) = 0.01 mm/r and \(f\) \(\geq\) 0.05 mm/r. Due to the higher temperature in the cutting zone during the formation process of the drill cap, the material at the bottom surface of the workpiece corresponding to the drill tip undergoes localized softening, and the formation of the drill cap is dominated by the rotational extrusion of the drill tip on the material of the workpiece at the bottom surface of the drill tip. In Figure 12, when the feed rate \(f\) = 0.025 mm/r, during the process of top hat formation, the temperature of the bottom material of the workpiece corresponding to the drill tip is low, and the hardness and strength are high, so in the early stage of top hat formation, it is mainly the cutting of the main cutting edge of the drill tip, and therefore the change in axial force is relatively smooth. When the top edge drills through the top of the cap, the axial force decreases. It can also be seen from the morphology of the drill cap that the top crack of the drill cap is larger when the feed \(f\) = 0.025 mm/r. The characteristics of drilling cap formation under different feeds also directly affect the formation of workpiece edge defects. At \(f\) \(\geq\) 0.05 mm/r, the axial force and temperature in the process of drilling cap formation are higher, and the overall increase with the increase in feed, the critical thickness and width of the workpiece machining layer corresponding to the overall outward plastic deformation below the main cutting edge increase accordingly, and the edge of the edge by the plastic deformation caused by the crimping and other defects is larger. At \(f\) = 0.01 mm/r, the temperature of the bottom surface below the drilling tip is higher, and the exit of the hole also has obvious crimping. As shown in Figure 13, the edge of the hole is relatively flat, 0.01 mm/r, the temperature of the bottom surface below the drill tip is higher, and the exit of the hole has an obvious curling edge. At \(f\) = 0.025 mm/r, the edge of the hole is more flat, as shown in Figure 13.  
The effect of feed on the maximum axial force during drilling and the maximum value of axial force in the linear change stage at the beginning of cutting is shown in Figure 14.  
From Figure 14, it can be seen that the axial force at the stage of overall convex deformation of the thin-walled plate at the early stage of cutting increases slowly with the increase in feed \(f\). This indicates that the feed has a certain influence on the conditions of the drill bit drilling into the thin-walled plate at the early stage of drilling, and the increase in axial force at a smaller feed is smaller, and the support force required by the drill bit for drilling into the workpiece is smaller, so the drill bit can start drilling into the workpiece after the thin-walled plate produces a smaller convex deformation; with the increase in feed, the support force required for drilling into the workpiece increases, and the drill can only drill into the workpiece after the thin-walled plate produces a larger convex deformation. From Figure 13, the maximum axial force changes to see the overall maximum axial force with the increase in feed \(f\) and increase; the reason is the same as the aforementioned.