Cause of failure: 928TC system uses tool rest. If T 1 1, T22, T33 and T44 are used for programming, the control of the hydraulic chuck may fail, and the hydraulic chuck may detect an error and give an alarm. It may also lead to the control error of the tool rest, and it is impossible to implement the tool compensation processing method: the commonly used programming of T 1 1, T22, T33 and T44 should be changed to T0 1, T02, T03 and T04 respectively, which is determined by the internal software programming of the system. When 928TC carries out tool compensation superposition, it adds several lines on the basis of the original tool compensation. If you can't add tool compensation, write down the tool compensation, add several lines on the basis of the original tool compensation, then reset the tool compensation in the system, and then re-enter the tool compensation.