# Prediction of Machining Deformation for Split Equal-Base Circle Bevel Gear
## 4 Experimental Section  
In the experimental part, the flatness of the bottom surface, the verticality of the left and right end faces, and the diameter of the inner and outer circles of the wheel blank are measured, and the correctness of the previous theoretical calculation and finite element analysis are indirectly verified through the analysis of the change trend in these parameters. Experimental verification is conducted using gears of the same material and specification as in the simulation. The main parameters of the split wheel blank are as follows: the inner and outer diameters are 626 mm and 804 mm, respectively, and the angle between the two end faces of the wheel blank is 36\({}^{\circ}\). In conjunction with the aforementioned simulation process, experimental verification is conducted using a three-coordinate measuring machine. The specific steps are as follows: First, the initial measurement of the processed split blank is conducted on the CMM. Second, the first tooth slot is machined for the second measurement. Third, all the tooth slots on the right side of the blank are machined, and the third measurement is performed. Finally, all the tooth slots on the left are machined, and the fourth measurement is taken. Each measurement includes the following elements of the gear blank: the flatness of the bottom surface, the verticality of the left and right end faces, the diameter of the inner and outer circles, and the angle between the left and right end faces. Figure 10 is the first measurement of the machined split gear blank. Figure 11a is the machining of the first tooth slot on the CNC machine, and Figure 11b is the second measurement of the machining of the first tooth slot. Figure 11c shows the process of machining the right tooth slots on the CNC machine, and Figure 11d shows the third measurement after machining all the tooth slots on the right. Figure 11e shows all the tooth slots processed on the left side, and Figure 11f shows the process of fourth measurement. According to the experimental design and measurement items, the gear blank is measured on the Hexagon CMM, measurements were taken multiple times at each stage of the experiment, and the data in Table 4 are processed arithmetic means. The specific measured values are shown in Table 4.  
From the measurement results, the measurement data of the gear blank during the first measurement is small because the tooth slot has not been machined at this time. But with the progress of multiple processing and the position tolerances, the shape, inner and outer diameters of the gear blanks all change significantly. The flatness tolerance of gear blank has a large variation range, which indicates that the wheel blank has a large bending deformation. During the machining process, the included angle between the two end faces keeps decreasing, and the included angle after machining is 0.005\({}^{\circ}\) smaller than  
Figure 9: Deformation diagram after all machining. that before machining, which shows that the gear blank will have opening deformation during machining. Moreover, the variation trend of perpendicularity tolerance of left and right end faces is opposite with the processing, which indicates that a certain amount of torsional deformation occurs along the \(X\)-axis of the gear blank and the deformation is mainly bending deformation after projection. The size of the outer circle is reduced by about 3 mm, which indicates that there is a large deformation in the Y direction. The data are consistent with the simulation results. The data in the third column of the table have a sudden change and do not coincide with the overall change trend, which can be the result of the measurement error.