# Study on the Position Deviation between the Iron Roughneck's Spin-Rollers and the Drilling Tool
## 3 Results and Discussion
### Experimental Results of the Spinner Mechanism with Single Follow-Up Roller  
The experimental results of the spinner mechanism with a single follow-up roller are shown in Table 4. The data in the table are representative data selected from many tests, covering the maximum and minimum position deviations of the drill pipe in \(x\) direction and several different position deviations in the \(y\) direction. It is evident from the test data that the position deviation of the drill pipe in the \(x\) direction ranges from 3.52 mm to 10.56 mm. When the position deviation of the drill pipe in the \(x\) direction is 3.52 mm and the deviation in the \(y\) direction is different, the spin action is completed differently. When the deviation in the \(y\) direction is 19.36 mm, the spin action is very unstable, and the rollers have poor contact with the drill pipe, resulting in obvious vibration and slipping, which affects the spin action. When the deviation in the \(y\) direction is 12.32 mm, 8.80 mm, or 5.28 mm, the  
Figure 11: Experiment involving the spinner mechanism with double follow-up rollers. Figure 12: Inclination test. spin action is smooth, the vibration is small, and there is no obvious slipping. It is evident from the experimental results that when the position deviation in the \(x\) direction is small, only when the deviation in the \(y\) direction reaches a certain value will the spin effect be seriously affected. In other cases, the spinner mechanism is in good working condition. When the position deviation of the drill pipe in the \(x\) direction is 7.04 mm, and the deviation in the \(y\) direction is 3.52 mm or 5.28 mm, the spinner mechanism can complete the spin operation, but there will be a certain degree of vibration and slipping during the working process, which will affect the spin efficiency. When the position deviation of the drill pipe in the \(x\) direction is 10.56 mm, and the deviation in the \(y\) direction is 3.52 mm or 5.28 mm, the contact between the rollers and the drill pipe is poor, resulting in greater vibration and slipping, which affects the spin action and may even render the mechanism incapable of spinning normally. From the above experimental results, it is evident that the position deviation of the drill pipe in the \(x\) direction has a great influence on the operation of the spinner mechanism, while the position deviation in the \(y\) direction has a relatively small influence. When the position deviation in the \(x\) direction of the drill pipe is small, the spinner mechanism can work normally within a certain range of position deviation in the \(y\) direction. However, as the position deviation in the \(x\) direction increases gradually, even if the position deviation in the \(y\) direction is small, the operation of the spinner mechanism will be seriously affected. This situation can be analyzed by combining the deviation relation curve between the driving rollers and the drill pipe in Figure 4c: (1) When the position deviation in the \(x\) direction of the drill pipe is 3.52 mm, it is evident from Figure 4c that the position deviations in the \(x\) and \(y\) directions of the driving roller are 2.82 mm and 6.79 mm, respectively. The offset is small, and the center position of the spin action can be guaranteed, so the spin action is relatively stable; (2) When the position deviation in the \(x\) direction of the drill pipe is 7.04 mm, the position deviations in the \(x\) and \(y\) directions of the driving roller are 5.63 mm and 13.59 mm respectively, which have a certain offset. During spinning, the contact conditions and forces between each roller and drilling pipe will be unbalanced, so small vibrations and slips occur; (3) When the position deviation in the \(x\) direction of the drill pipe is 10.56 mm, the position deviations in the \(x\) and \(y\) directions of the driving roller are 8.45 mm and 20.38 mm respectively. In this case, the deflection of the driving roller is large and obvious, which results in a certain degree of deflection when spinning.